In order to fit a disc brake, you need a compatible fork and a compatible wheel, plus a compatible brake lever.

Your fork does have a disc brake mounting already designed in, it is an International Standard (I.S.) mount. Most mtb brakes now are Post Mount fittings so are fitted using a simple adapter. You can see the differences here or search around images.

To fit a disc brake you need a disc compatible wheel of the correct diameter (check the current size), the caliper and maybe a lever. If you have V-brakes now, you could add a mtb specific, cable-operated caliper to the existing lever with a new cable and housing. Alternatively you can get pre-bled hydraulic disc brakes, comprising the lever, caliper and disc, ready to use out of the box. N.B. there are two standards of disc mounting, 'six-bolt' and 'centre lock', match this to the new wheel hub.

Bear in mind that because you need a wheel change, changing to a disc brake could be expensive relative to the value of the bike (which is of course not always monetary). It's up to you to decide the best use of the money; that might mean upgrading this bike, or it might mean saving up towards a disc brake specific bike, new or used.

An interim upgrade could be a high quality brake of the same type you have; if it is a V-brake, good models are quite affordable and do make a noticeable difference over basic models. Also, with rim brakes particularly,  high quality brake pads noticeably increase performance for not a lot of money.


Giant Atx MTB rear wheel quick release not opening

You can use a pipe that you wrap around the QR to have a bigger lever, but be careful not to apply to much force (because you will have a lot more)!
If the lever is stuck against the frame (so you cannot place your fingers around), try with a screwdriver first to pry it open(but put a cloth or something to prevent damage on the frame).

Perhaps the axle of the QR is rusty? -> WD40 then :)


A 11 speed cassette would mean a new hub (probably a new wheel realistically) and likely a new derailleur to match the cable pull of the STI shifters plus the labor (this includes installation of the new cable stops, new cables, re-wrapping the bar after putting on the new brifters, etc.). You will also need to spread the frame to get a modern hub in there, which we can count under labor.

If you want to keep the bike: You're better off putting on a new 7 speed cassette or freewheel depending on what you have (I'd guess its actually a hub that takes a freewheel) and either living with the current shifters (downtube shifters are lovely and incredibly reliable when you get used to them), going bar-end shifters, going Retroshift or putting a Shimano derailleur and using the 7 speed Shimano Tourney ST-A070 (there is a double & triple version) or compatible Microshift shifters (SB-R472 for doubles/SB-473 for triples).

If you want to get a new bike: The price of STI shifters and the fact that 7 or 8 speeds is more than enough makes a new bike (or a used bike with STI shifters) a good option unless you're particularly attached to this frame (and everything else is in decent condition or good enough condition that you're willing to bring it to acceptable for you).


Shimano GRX 2x11 brake rotor compatibility

In all honesty, you can use any disc you like, and from practically any manufacturer as long as the dia. (and fitment type) is the same.


How do I clean chain grease off my clothes?

Most ordinary baby wipes will get grease out of clothing if you get to the stain quickly enough - or, at least, get enough of it out that the rest will later wash out. You can also carry spray-n-wash pads or keep them in your desk at work. However, baby wipes are also good for cleaning your hands - handy after changing a flat, or fiddling with a bike chain.

However, it's even better to avoid getting grease on your clothes to begin with, so I suggest using a pants clip or rolling your right pants leg up. A full chainguard is great for this, but it's not always practical on a commuter bike. This won't prevent the problem completely, bit it does help minimize it.

For these reasons, I found that when I was commuting, I tended to favor my black or dark-colored pants.


How much motor do I need for my electric-assist bike?

A highly trained competitive cyclist can ride at ~ 350-400 watts of power output for a 2 hour ride.  So adding a 400 watt electric assist motor is roughly equivalent to adding a competitive cyclist 'stoker' to your rig.  The speed and battery size make a big difference but here are some rules of thumb:

Some motors are measured in horsepower, rather than watts.  1/2 horsepower is roughly equal to 400 watts for this use.
A 400-watt motor will usually be sufficient for the average rider. Your rig is a little heavier, so you might want to go with higher watts.
On a typical 400 watt rig, two 12-volt, 12 amp-hour batteries will take an average rider 10 miles at 15 mph or up a hill that's 800 feet tall.
To go faster (assuming you haven't maxed out the watts) or further, you need to increase the battery - range is proportional, so twice the battery size = twice the range at the same speed.

There are companies like Convergence Tech that sell kits for motors in the 1 horsepower range that are pretty easy to add to an existing bike if you are mechanically inclined.  That range is probably more than sufficient for your needs.

Be aware that some areas limit the top speed or the available power for electric or gas-assisted bicycles.  I've seen speed limits of 25-30 mph and power limits as low as 500 watts.  You will want to check with your local road or transportation department to make sure you comply with local regulations.


This is Bicycles.SE, we're more aimed at helping you overcome practical problems.  Since its a nice looking bike, why not fix it?

Please tell us more about the problem/damage, with photos of the broken parts.


Can you run a quick release skewer with a SON dynamo hub?

Yes, they don't care, you can use any QR you want. I've used an early SON28 with the stock one, a Pitlock, an external cam light skewer, and various Shimano skewers, and a current SONdelux with the stock one and a Shimano QR. It doesn't matter.
I don't know the numbers but I believe internal cam skewers develop quite a bit more clamping force than bolt-down skewers, so in other words it's conceivable to make a hub that could care about this distinction. But Schmidt hubs don't.


Understanding how to calculate critical power curves

There are a couple of different versions of the CP model. You are looking at the earliest, simplest, two-parameter model proposed by Monod and Scherrer in 1965. While there have been modifications and expansions of the original model since then, the basic simple model has enough features that you can understand it. Although CP has been described as "the power that could be sustained indefinitely," in practice it works fairly well from durations of perhaps 3 minutes out to around half an hour -- additional parameters have been proposed to address durations before and after that.

If you have been riding with a power meter for a while you've undoubtedly seen a curve as you described, showing maximal average power in watts over durations in time. The simplest way to understand the Monod-Scherrer model is to notice that a watt is a Joule per second. So, to get Joules of work, multiply the power in watts by a duration in seconds. Monod and Scherrer noticed that if you plot Joules on the y-axis and time in seconds on the x-axis, the relationship is nearly linear for durations from around 3 minutes out to around half an hour. A linear relationship like that can be approximated by a line with an intercept and a slope. The slope is what they called CP, and the intercept is what we now call W'.

If Joules(t) = W' + cp*t, then an equivalent formulation is the one you've already seen. Since a watt is just a Joule per second, just divide the equation by time on both sides to get watts(t) = W'/t + cp. In this formulation, if you plot watts against time, CP will be the asymptote and W' will be a constant that determines a hyperbola. You can see why some people prefer the intercept and slope formulation rather than the asymptote and hyperbola formulation.

Note that because W' is the y-intercept, it describes an amount of energy in Joules; because CP is a slope in the regression of Joules on seconds, it describes power in watts. Thus, if CP were 200 watts and W' were 15000 Joules (= 15 kilojoules), then a prediction for the amount of work you could do in 600 seconds (= 10 minutes) would be 15000 + 200 * 600 = 13500 Joules over 600 seconds, or an average of 13500/600 = 225 watts. You can think of W' as a "stock" of energy (like a storage battery) that you can expend in addition to the steady state power you can sustainably produce (that is, CP). You can expend that W' quickly or slowly but once the battery is run down you have to recharge it. In this example, you were expending it over 600 seconds, so another way to think of it is this: if your CP were 200 watts and you have 15000 Joules of stored energy, your baseline is 200 watts and you can add to that 15000/600 = 25 watts for a total of 225. If you expended it over 300 seconds (= 5 minutes) your baseline is still 200 but you can add to that 15000/300 = 50 watts, so your predicted maximum power for 5 minutes would be 250 watts. This alternative way of calculating predicted maximum power is Watts(t) = W'/t + cp.

In either formulation, if you have values for W' and CP, you can calculate the estimated power for any duration from around 30 seconds up to around an hour. (If you use the Joules formulation, you just have to divide by the duration to get watts). That's how the CP curves that you've seen are calculated: using values for W' and CP, you can create a curve and plot it showing predicted power at any duration. Note that with only two parameters, the model implies a power duration curve that has an asymptote not only at CP, but also one with the y-axis at zero duration. This is why models with more parameters have been developed -- to deal with the asymptote at zero and the asymptote at long durations.

From a practical perspective, typically your curve of time to exhaustion will not be "smooth" if you base it on just a single ride -- usually, you combine the maximal durations for several rides over a few days or weeks. Also, to get reliable estimates of W' and CP you'll want to make sure you've put out maximal efforts. A typical procedure may be to do maximal efforts at, say, 3 minutes, somewhere in the range of 5 to 8 minutes, and perhaps somewhere in the range of 15 to 20 minutes. That will give you 3 data points. You want these efforts to be maximal for the targeted duration, and typically that means you want them to be relatively steady -- there will always be some variability in your efforts but you don't want the efforts to be repeated sprints of 30 seconds followed by 30 seconds of recovery. Aim for the maximal output you can sustain. I don't recommend that you do these 3 efforts in one ride or even over 3 consecutive days -- space them out over a few days.

That procedure will give you 3 data points of maximal power and durations. Convert to Joules, and calculate the regression slope and intercept. A side effect of this is that you will have the usual regression diagnostics, with standard errors for the slope and intercept and an R^2 so you can evaluate goodness-of-fit. If you do more tests, you can use more than 3 data points for your regression.


You can get hard shell bicycle storage, but they're usually heavy, expensive and fragile. These panniers on Amazon are typical. Yes, they have a rigid shell and look sort of solid, but in practice the sort of knife that will cut soft-wall panniers will also cut these. Partly because decent panniers are made of quite strong cloth, and partly because really solid panniers end up weighing more than most people are willing to carry. The motorbike "Metal Mule" systems weigh 5 or 6 kg just for the boxes.

For low-value stuff like you're talking about I suggest just using normal panniers and locking those to your bike with a cheap padlock. Make it nice and visible to discourage casual theft - someone can still rummage through them and get stuff out, but they can't just grab the whole pannier.

The next step would be a metal luggage net that you can put over the panniers and lock to the bike. It's still pretty lightweight and makes it really annoying to get things out of the panniers.

For real security I think you'd need to make something yourself. Buy a box that can be secured and bolt it to your rear rack, probably with a bit of wood between box and rack for reinforcement. Where I live (Australia) there are a lot of those aluminium boxes you see on tradesmen's utes/trucks, and a custom smaller size one for your bike would probably cost about the same as the carbon fibre panniers above. My custom toolbox for home cost me about $200 but it's nearly ten times as big as you'd want to put on a bicycle, a smaller custom one should be under $100.


How do I calculate calories burnt using my bicycle's weight?

To be honest, you're really asking this question too late. If you had asked before your tour, I believe the easiest way you could have measured it would be to find a cycling app which takes your weight and your other physical information. Then you simply weigh your fully loaded bike and add that weight to your own, then the app would measure your total calories burned. (Even this would only be a rough estimate).

However, there is no solid answer to this question. As I said before, you would have been better off asking this prior to the trip, as there are dozens upon dozens of factors needed to give you an accurate BALLPARK of how many calories you've burned. (I.e. Speed, terrain, average gradient, food consumed while on your trip, average power output, length of time spent in the saddle, cadence, over all distance, e.t.c.)

I suppose if you wanted a very rough estimate, find a calorie calculator online, input the total weight, (you and the loaded bike), take the distance traveled, and the estimated total time in the saddle. This method would be fairly inaccurate, but without the factors listed above, I believe it's the closest you would get.


How do I keep my pants/trousers from getting caught in the gears?

There are basically four solutions that do not involve extensive work on your bike:

Roll up the pant-leg on the gear-side high enough to stay away from the gears.
Wear tight fitting cycling pants that don't flap.
Use braces as you have, or clips such as these to keep your flappy pants close enough to your legs.
Stuff the pant-leg on the gear side in your socks.

Since option 3 doesn't work for you that leaves you with options 1, 2 or 4. However, when applying the braces or clips, (or stuffing your pant-leg in your socks) are you taking care to make sure all the excess pant-leg material is collected on the outside of your leg, away from the gears?

On the bicycle side: Chainring guards might help a bit, even better is a full chainguard but these may be hard to find for your bike.


Those are just gear cables, you will need to buy brake cables and outers.

Good on you for building it yourself, it's definitely do-able with a modicum of skill and even with limited experience. But... there's quite a few things you can do slightly wrong that will make the bike unsafe to ride. I think it would be good to have someone check over the bike before you ride it.

There are lots of online tutorials showing you how to install brake and gear cables, any search engine will find them for you (I couldn't find one using the search box on the top right of this page). Similarly for most of the other steps, and finding this site will hopefully help you with the other questions you'll inevitably come up with.

Also, it's probably worth reading some of the questions here about upgrading components and building from scratch, as it almost always works out more expensive than buying a whole bike, and can be hugely more expensive. Unless you work in a bike shop or can otherwise get new components at wholesale or better, it will be more expensive. That's especially true if you compare a second hand bike to buying new parts. Note that buying second hand parts to fit an existing bike is a fairly skilled task (you need to know how all the sizing works on the various parts as well as which parts will work with what you already have).


Just bought a vintage Sprinter Gran Touring, where to find info?

'Gran Touring' alludes to 'Gran Sport' and 'Gran Turismo'. These were Campagnolo names used in former times for their derailleurs. I am not old enough to remember when those former times were, but they were decades and decades ago!

The brand means nothing if this is a department store bike. That means you have free reign to do what you like with it. You can even get it shot=blasted with braze-ons for those cables if you really wanted. Personally I would be tempted to keep the cables as is but maybe get some proper clips to hook them onto the frame. You can get them from a retro bike specialist, e.g. one that does Sturmey Archer 3 speeds.

The geometry and ride should be good, maybe put the seat back so it is mid-rails instead of inch or so forward. Thebolt holding the seat on should go behind the seatpin, not in front.

I guess you have a non-standard wheel size, treat yourself to some Schwalbe ones to fit, read the ERTRO size off the side and special order from your LBS accordingly. In that way you won't have to pay postage. Modern Schwalbe tyres will be consistent with the bike and be puncture 'proof'. This will make the difference between oddity and everyday utility bike.

Bikes of that vintage had saddlebags for carrying stuff, consider getting one as this will make the bike look better than it is, albeir doubling the price if you get a UK Carradice one.

Those 'Northroad' bars are really comfy when riding in traffic or on bumpy trails. The turning circle will probably be that of a bus with that steering rake so adjust your riding style accordingly.

If you are doing a full refurb then give yourself a whole weekend for re-packing the bearings etc. Some sizes may be non-metric, that might be to watch out for. Given the super paint quality apart from the top-tube scratches you could just ride as is and put some 'One Less Car!' stickers on the top-tube after you have got the 'gran touring' stickers off. Steal some nail-polish remover from someone female if you haven't got any useful thinners for that. T-Cut should bring up the shine on the chrome not that it really needs it.

Very nice find, definitely just a department store bike though, which is good because you can do what you want to it without destroying some notional priceless heritage.


How do you install a bicycle pedal without a wrench?

If you can get it to start on the threads by hand then you can tighten it enough that you should be able to ride carefully home. I've done this before, but its messy (as in, on your fingers).

The threading should make the pedal secure itself (or at least not back out) when pedaling forward, but might get wacky if you tend to backspin or goof off with your feet at intersections. Of course, if your cranks are on backwards...


How do I install a bike seat clamp properly?

Position the clamp so that the open section of the clamp is oriented to the slot in the frame. If the frame slot faces the rear the opening in the clamp should also face the rear.


Right Shimano SPD pedal clicks on down stroke

It's a case of systematically hunting down the source of the click. As Andrew Henle said in a comment it's very hard to understand where a noise is coming from when you are riding on the bike. Once I was convinced I had a click in my bottom bracket but it turned out to be a slightly loose seat clamp.

Try wearing normal shoes and pedal on the SPDs (awkward, but can be done). That will determine if it's the pedal/cleat interface.

If it's still there check for play or roughness in the pedal bearings. Take the SPDs out and re-install your old pedals.

If it's still there then you need to start looking at the BB or drivetrain.


I refurbish a lot of older bikes for re-sale.  The first thing I do is to pop off the wheels and manually turn the axles to see if the bearings are suspect.  If the axle turns roughly, has side-to-side play, or is hard to turn...They probably do.

There should be "no more friction than supplied by the grease" when turned by hand.  You cannot do this with the wheel on the bike.
If you have the tools; cone wrenches and such, then a wheel rebuild is both easy and cheap.  The best-grade #25 bearings are inexpensive.   If the cones are shot it's a different story.

Time?  My police patrol bike, with well over 3000 miles, still feels perfect.  If you ride in the rain a lot, or ride off-road through mud and sand and through water crossings, naturally you're going to need more frequent maintenance.
Bearings are something to check say...Yearly for most riders.


With accurate vernier calipers or a micrometer, measure the width of the outside plates.
https://en.wikipedia.org/wiki/Bicycle_chain#Width shows this table of chain widths.

Speeds
Width

6
7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)

7
7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)

8
7.3 mm (9⁄32 in) (Shimano HG), 7.1 mm (9⁄32 in) (SRAM, Shimano IG)

9
6.5 to 7.0 mm (1⁄4 to 9⁄32 in) (all brands)

10
6.0 to 7.0 mm (1⁄4 to 9⁄32 in) (Shimano, Campagnolo)

10 (Narrow)
5.88 mm (7⁄32 in) (Campagnolo, KMC)

10 (Narrow, Direction)
5.88 mm (7⁄32 in) (Shimano CN-5700, CN-6700, CN-7900)

11
5.5 to 5.62 mm (7⁄32 to 7⁄32 in) (Campagnolo, KMC, Shimano CN-9000)

12
5.3 mm (13⁄64 in) (SRAM)

So if your chain is 5.8mm wide then its probably 10 speed, and 5.6mm is likely 11 speed.   The difference is small, 0.2mm is about 8 thousandths of an inch, you're not going to see that on a ruler.
However if you had known 10 or 11 speed chain laying flat on a tabletop, and your current chain flat beside that, you should see a visual difference, or at least feel one with your fingers.

Another idea is to look for a quicklink or master link.  Many of them have 10s or 11s stamped into the sides.  You're unlikely to get an 11s master link to close on a 10s chain, but the opposite is certainly possible.


Shimano 105 ST-5500 gear sensor mechanism

Here's a screenshot of part of the instructions (Shimano pdf) that appear to match your levers.

You're right, there is a 4 pin cable in there, but I have no idea where you'd find out what the pins do. I strongly suspect it's a classic +power, +signal, -signal, -power layout but whether it's analogue or digital I don't know (it might just be a potentiometer). You would need to take it apart yourself and have a look, sorry.


What is the best breakfast right before cycling?

Entirely depends on the lenght of ride. If you're riding for less than 2 hours then your body already has everything on board that it needs. If you're working for more than 2 hours you should eat complex carbs (pasta, oatmeal) 2 hours before the ride so that they have time to digest before you actually need them.

Also eating too much just before can limit your performance as your body also has to work to digest a load of food in your stomach. Adding links to answer the comment below.

Eating and exercise: 5 tips to maximize your workouts
What to Eat Before Exercise
Eating for Endurance Running

I eat a small bowl of Cheerios with some fruit thrown in for flavour. I ride most morning at about 5:30am. If I'm working hard (either 2 plus hours or 2 hours really hard workout) I'll carry some Gatorade diluted 50/50 (I find it's easier on my stomach).

When I ride 100k+ or century length I make sure I get up and eat 3 hours before the ride. Then drink 50/50 Gatorade till the ride. During the ride I drink both 50/50 mix and water. I also start refueling with food after about 30 minutes. Small bites of energy bars, bananas, whatever your stomach can handle.

What type of conditions do you ride in? Is it really hot? Are you drinking enough fluids? If you lose more than 2 pounds on a ride you're not drinking enough. What is your exertion level? Are you going too hard for too long for your fitness level?

Someone below also mentioned protein. Many of the 'higher end' sports drinks also come in a protein variety. The reading I've done at the very least suggests that you eat protein and carbs within 30 -45 minutes after a ride to maximize the recovery/refueling of your muscles.


Do I need a new chain after 1300 miles (2100 km)?

As a general rule you get about 2000 miles out of a chain, but this depends on the chain, it's maintenance, and the use and storage conditions.

It's not out of line for certain brands of chains to need replacement in 1300 miles, since some are either cheaper (and hence more poorly constructed) or more expensive (and hence lighter, with less "meat").  And the more aggressively you ride the faster the chain will wear.

But the real test to see if a chain should be replaced is "chain stretch", using a chain wear indicator.  Generally a chain should be replaced when "stretch" exceeds 0.75%, as measured by the tool.

(In a pinch you can crudely check a chain by measuring against a ruler.  Links are exactly 1" apart when new, and if 10 links are more than 1/10th inch longer than 10 inches then that's 1% wear.)

One thing you definitely don't want to do is to run a chain beyond the point that it's "too worn" -- this causes damage to your sprockets and can cost you several times the price of a chain.


It's probably the gear cable. Over time, grease and dirt get trapped inside the plastic housing. I would recommend replacing both the inner and outer parts of the gear cable (note they are not the same as brake cables). You'll need an end cap and ferrules as well


Aluminum seatpost stuck to a steel frame

I have an identical problem, having been rinding the bike without seat clamp for more than two years now.

I suppose you have already read something about it, if not I recommend Sheldon Brown on the subject. But I must warn you that the ammonia theory didn't work for me, and I tried ammonia on some aluminum sample parts without any visible effect (corrosion, oxide removal, whatever).

The problems are:

Aluminum oxide occupies more space than pure aluminum. This, oxidation of aluminum posts create EXTRA VOLUME inside the seat tube, and this can create huge forces;
Aluminum and steel create a GALVANIC PAIR of metals, inducing electrolytic reaction between them, with dire consequences as you have already noticed.

I believe the solution, failing the chemical approach, must be oriented towards two possibilities:

Dilation, a drastic one, but TO THE COLD! Since aluminum dilates more than steel, you should FREEZE the seatpost, by pouring some very very cold substance inside. Liquid nitrogen (frostbite danger), dry ice (perhaps not cold enough) and CO2 cartridges (doesn't remain inside for too long) are good candidates. Perhaps if you wrap a towel around the seat tube, pour boiling water on it, then pour the freezing stuff of your preference inside the seat tube, you'll crack the bond indeed, as you planned.
Total mechanical disintegration. You'd look for some heavy machining tools (lathes and all) and eat the post from inside. Some damage to the inner surface of the seat tube is very probable.

I don't believe too much in brute force if the seatpost is frozen inside for too long (more than three months since last "movement"), but skilled shop owners have been asuring me that it is possible (I didn't go all the way with this for now because fortunately the current seat height is working and I don't want to risk being too many days without the bike).

Hope this helps, send some feedback if you get some result!


My rear wheel isn't properly spinning. How can I tell whats wrong?

You should take it to your local bike shop and get the wheel dished and trued. It is probably a mix of both those issues. Depending on how bad it is you may need to replace the wheel entirely.


You can easily inflate a completely flat tire (provided the tube is still good). Usually, when a tire is completely flat, you have to press the back of the tire so that the valve doesn't recess into the tire so your pump can be attached properly to it.

With a presta valve, you can use your mouth for this (well, on a clean tube, since the valve stem isn't spring loaded), but with a schrader valve you have to use a pump.

If it still won't inflate, check the tire and tube for damage and replace accordingly.


Can I replace hood covers on Shimano ST-2300 brake/gear levers?

An ST-R9150/R9170 hood is not going to work on an ST-2300 shifter.

R9150/R9170 is Dura Ace DI2 - electronic shifting.  This is an ST-R9170 shifter:

ST-2300 looks like this:

Note the significant differences, especially in the "cap" area, where the ST-R9170 hood extends forward over the top end of the shifter, where on the ST-2300 that same area is a hard Shimano logo.

Your best bet is to look for ST-2300 hoods on large online retailer and auction sites...


This is the first time I've heard of such thing. Here's my analysis of it.

I'm assuming the magnetising of the drive train is referring to the chain and rear sprocket (if it's a hub motor). These components could theoretically become magnetised through rubbing if they travel through a magnetic field in one direction (either north to south poles or vice versa). They have to contain iron for this to work.

Ebike motors are mostly brushless, which have permanent magnets inside. And also the chain and sprocket is often made of stainless steel (more below). So it sounds possible that those components could be magnetised as you would mostly pedal forwards.

However, here are some doubts to whether it needs to be demagnetised:

Magnets made from rubbing are only temporary. They lose their magnetic field over time and knocking.

The magnetic field around a brushless motor is complicated, as there are multiple permanent magnets inside arranged in a circular fashion. So any rubbing may be cancelled out by this arrangement.

Some stainless steel actually can't be magnetised. I haven't checked yet but you can by holding a fridge magnet and see if the chain and rear sprocket reacts to it.

The only debris that would stick due to magnetism is ferrous materials. Most debris in cities are not. But that  would largely depend which geographical area you're in.

In conclusion, I'm very doubtful whether this is needed at all. And as you've mentioned, there are magnetic sensitive sensors on some Ebikes. Demagnetising could potentially damage them and the motor.

Some sites I used to confirm my understanding:

https://sciencing.com/magnetize-things-6377.html
https://www.google.co.nz/amp/s/m.wikihow.com/Magnetize-Steel%3famp=1


The metal bracket is designed to fit the lugs of a water bottle cage.  If you have a bottle cage, the bracket goes between it and the frame. If you don't, it can just be mounted directly: the lugs on your frame will already have bolts in them, to stop the rain getting in. In either case, you might need or want to bend the bracket a bit, either to give more clearance for your bottle or to move the pump more within the frame. That shouldn't damage the bracket, as long as you don't bend it right back on itself or repeatedly bend it back and forth.

Mine lives on my down-tube. Unless it sticks out a long way, your legs shouldn't come close to it and, in any case, the pump will be between your legs and the bracket. If you're still worried about slicing your leg open, use a metal file to round off the edges and remove any burrs. Actually, that would probably be a good idea anyway to avoid hurting your fingers when you need to use the pump.


What would be the handling of a bike with reversed stem?

I actually have a VO Grand Cru stem angled back toward me. With the trekking bars, it works for my modest mostly-upright-posture purposes. No effect on bike handling that I can tell. If I get a yen to lean further forward someday (unlikely, with my middle-aged back) I'll flip it.

Adjustable stems can also be persuaded to do this. So it's possible, just not common.


You should not try to adjust your riding position by messing with the steering geometry. Riding position should be adjusted by replacing the stem with one that is longer or shorter of has more or less rise.

However, it sounds like you need a longer fork anyway. 375 mm axle-crown sounds far too short. I put a rigid fork on a 90's 26" wheel MTB that only had 40 or 50mm travel and the axle-crown was 420mm. I suspect you have steepened the head tube angle too much which is why the bike steering is too fast.

It's possible to make an estimate of the crown-axle measurement of the original fork by making some relative measurements on a high resolution image of the bike knowing the rim diameter is 559mm. The Trek archive page of the 2014 820 is here which provides just that. I estimate the axle-crown is is more like 460mm.


How I can see who watched my Strava profile?

No, you can't.  You can only see who is following you, not who is just looking at your profile/rides.


What percent of crashes are due to bicycle failure?

There are some statistics available from Great Britain for Contributory factors for reported road accidents. Below are the 2014 figures for Pedal Cycles, the first column is number and the second is percent.

Note that only reported accidents where a police officer attended the scene are included in the statistics. This Wikipedia article has some details of the methodology used to collect the statistics.

The complete data set is available here. The data above is taken from the table RAS50005 - Vehicles in reported accidents by contributory factor and vehicle type, Great Britain, 2014.


What is the impact of changing to a smaller chainring?

I would consider changing your crankset to a true compact, 50t/34t, and running an 11/25 rear cassette.

Campy actually made a specific derailleur for running a compact front, because they said that the 50t doesn't work well with the standard front derailleur (that may be a function of the tooth differential, so it may not apply if you leave the 39t in place).

(Edit: It does appear that my data on the campy front derailleur may be outdated. Their 10 speed Chorus and Record had an individualized front derailleur, but current product appears more universal.)

The 50t x 11t combo is a 119.6in gear, compared to 107.2inches for the 53t x 13t you're running now.

It will give you a slightly faster gear than current, a better climbing range, and slightly crisper shifting. Downside is you have to buy the crank set and cassette, not just a chain ring.

Check out UBI gearcalculator for more info on how gearing changes will affect you.

Hope that helps.


Locknut on threaded headset doesn't tighten

Well if both nut and the lock nut are skipping then chances are that thread on fork is stripped. Maybe it would be possible to repair threads on the fork, but since you have been in the accident it would be vise to get your fork and headset examined, maybe there are some other issues with it now.


Should I fight a ticket I got for riding my bicycle in a crosswalk?

According to Santa Barbara City Ordinances:

10.52.130 No Bicycles on Sidewalk.
No person shall ride a bicycle on any sidewalk except at a driveway; provided, that a person may ride a bicycle on any area designated by the City Council as a bikeway.

So, unless this was a designated "bikeway," you were clearly in violation of at least one law. I'm a little unclear on your story, but it also sounds like you crossed against the signal. That would, of course, be a second infraction.

You mention that you live on a one-way street but were crossing at a four-way intersection. This doesn't make sense. A two-way street crossing a one-way street is a three-way intersection. But I'll do my best to make sense of it.

If you were riding on the sidewalk on the left side of a two-way street, or if you were riding the sidewalk against traffic on a one-way street; the ticket for riding against traffic also sort of makes sense. It may or may not be entirely correct, but a case could be made.

In short, you were clearly in violation of some law, probably several. If you try to fight it, you may get out of the ticket you were specifically given but you may also end up with several others.

I would also encourage you to read all of section 10.52 in the attached city ordinances as well as the California Vehicle Code Sections 21200-21212, all of which pertain to bicycling in California. For the best understanding, read the state laws first and the local laws second and look at the local laws as an addendum to the state laws.


Years ago, the US Airforce commissioned the design of a 'perfect cockpit' for a new fighter, spending millions measuring and testing pilots and coming up with the right cockpit for the perfectly average pilot. Only to find there was no perfectly average pilots to fly plane. After that, they made planes with cockpits adjustable to the actual pilots that was flying the plane.

Bikes take this further - the frame is not adjustable without making it heavy and unreliable, and unlike an aircraft, frames are relatively cheap compared to the the rest of the kit. Its cheaper and gives better bikes to make different frames.

All that aid, the bike might fit you - The US Airforce never found their perfectly average pilot, maybe the manufacturer of that E-bike has found there perfectly average rider in you.


How to mitigate the risk of riding on highways

Google is probably not the best tool for this, it's not tailored to the needs of cyclists. I would always use BRouter, here is the route it produces when I ask it to give me a safe route. The route is quite a bit longer, but I'd guess that there are pretty few major roads without bike lanes on it.
BRouter is a nice tool that builds on OpenStreetMap data, and allows you to select (or even define your own) different goals (safety, fast, walking, non-hilly, etc.) for which the route is optimized. It even allows you to generate some alternative routes. I've found the results of the "safe" optimization quite solid, there have been pretty few places where I decided that the chosen route is not safe enough for my purposes.


Does a slightly untrued wheel damage the wheels?

It won't present any immediate danger, however it became untrue for a reason. If the spoke tension has changed more than likely it will get worse over time and riding it while out of true will most certainly expedite that process. Other spokes will lose their tension and could possibly break resulting in a higher repair bill, or possible injury.

You will not immediately damage the wheel or rim but continuing to ride on it will only make it worse. It will also put stress on other aspects of the bike as well and your braking - if rim brake, will likely be slighty less effective.

All of these would be after a while though, so while there is no immediate danger it will get worse the more you ride. Hitting a curb with poorly tensioned spokes could cause one to "pop"


Such rubber rings are supposed to keep gear and brake cables from rubbing against frame tubes. That is, when the cables are mounted openly outside the frame.


How can I prolong the life of my bottom bracket bearings?

Actually, IMO Hicks is right in the comments under the question. Now, had the problem been really that the BB is wearing out:

After you have been out in the wet, on returning to base (home), remove the bicycle's seatpost and turn it upside town. You will be surprised how much water runs out!

You might also want to try sealed cartage BB or external bearing BB. By the way, ordinary (not cartage) bearing are extremely inexpensive: 0.5 euro at my area.


First I would determine for certain that the levers are compatible with the disc brakes.  They should be long-pull levers  and will be compatible with linear pull (V-brakes) rim brakes.  Being a new bike, I would think this should not be a problem if sold by a bike shop.

Next, I would check that you have proper cable tension. You may have to remove all slack from the cable by loosening the pinch bolt and pulling more cable past the bolt, effectively tightening the cable.  Also of use would be turning out the lever's barrell adjuster (anti clockwise) which also tightens the cable.  This is the rounded end of the lever where the cable exits the lever. On brake barrell adjusters there are two threaded parts that
move. The smaller one closest to the lever is a lock ring. When you've set cable tension appropriately with the longer cylinder shaped adjuster, you set this in place by turning the round part tight to the lever.  To make any adjustments after this you'll first need to loosen the lock ring. Essentially, determine if any slack exists in the cable and correct this.

The lever travel is typically set with a small set screw found on the inside (toward rider) of the lever body, the part of the whole lever assembly that doesn't move. Tightening (clockwise) this screw shortens the travel.  This maneuver, however, won't really help your problem since you experience inadequate braking  to begin with. The lever travel screw works essentially by pushing the lever toward the handlebar, and is the same as the first few millimeters of lever closure your fingers do now.  Shortening the travel won't help.  Lengthening the travel by loosening the set screw  initially puts slack into the system so without further cable adjustment, you're pulling the same amount of cable and therefore braking is unchanged.


Better to go with a longer spindle length bottom bracket or shorter?

I have just rebuilt a 1990 Raleigh bike (exact model unknown) and tried several bottom brackets to find the best. This turned out to be the one that brings the smallest chainring (in your case only chainring) closest to the chainstay without touching it. The one I've ended up with is 117.5mm whereas the original was 122.5mm. The front derailleur works perfectly (not applicable for your setup) and the chainline looks great, albeit aimed at the larger cassette ratios rather than the smaller ones.
My logic is that when on the larger sprockets I am putting a lot of pressure on the pedals, so a straight chainline is best for chain strength and wear. When in the smaller sprockets I am usually on the flat or downhill, so a bit of chain angle is not such an issue.
Thus, I would go for the shortest BB you can get away with to keep the chainline close to the chainstay, and minimise flexing forces on the BB stubs (are they called that?)


Can I use Shimano 8 speed rear deraileur (Claris) with 6 speed SIS downtube shifter (for a 6 speed freewheel)?

Proper indexing of the derailleur cage relies on two things:

Length of cable pulled per click of the shifter.
Derailleur actuation ratio (how many mm the derailleur cage moves per mm of cable pull).

If the derailleur is swapped for another with the same actuation ratio the indexing will be unchanged.

Shimano used an actuation ratio of 1.7 from 6 speed to 9 speed mountain and 10 speed road. (Source: Arts Cyclery Blog - Drivetrain Compatibility).

So yes, the 8 speed Claris derailleur should work with the 6 speed shifter and 6 speed freewheel.


What are the absolute essentials a cyclist should own?

This is what I tell everyone to get first when they get a new bike:

Seatbag, to hold the following:
Spare tube (maybe two)
Small multitool
Mini-pump or CO2 inflator
Tire patch kit
2x tire levers

That assumes you have bidons and cages.  Those six things should get you by for many miles and should get you out of any trailside emergencies.  As with anything though, make sure you know how to use them when the need arises.  For your own personal bike shop, I'd recommend a good floor pump with a pressure gauge, some high quality chain lube, and a maintenance book for DIY repairs.

Also a helmet should be entirely recommended as a required purchase, and probably front and rear lights.  Nothing hurts worse then getting hit by a motorist that "didn't see you" at an intersection.


New tubeless setup: losing air through spoke holes

It seems like there is a problem with the rim tape. The tape should seal the spoke holes without milk. Try cleaning the rim and replacing the tape if it is still loosing pressure.


Using 16 hole front rim to build a rear wheel

Sixteen spoke rear wheels do exist, but there aren't very many of them, and to function they need to have extremely stiff and strong rims. In this case, being a Dura-Ace product, it's reasonable to assume that the everything has already been pushed to around the limit in the design. In particular, making one of these a rear would require the compromise of either pushing the drive side spoke holes way beyond what they were expected to endure in terms of resisting cracking, or making the whole thing have way less tension than intended, resulting in it being weak. Just winging it and assuming you'll be fine is not a good idea here.

These limitations don't have to do with the rim being carbon per se.

Worth mentioning but pretty far down the list of issues with this plan is that the sort of rims these are (deep carbon rims in an ultra-premium prefab set) can have directional drilling that will contort the nipples around if a pattern other than intended is used.


Drum brake that fits on a Brompton fork?

70mm is the diameter of the brake drum. There is model XL-FD which is labeled as "90mm Front Drum Brake Hub" that has equal width but larger drum. The respective pitch circle diameters are 89.9mm and 109mm, which places the spoke holes 9.5mm away from the drum.

So, the OLD is 100mm, which is standard for most bikes but unfortunately does not fit Brompton.


In my experience you mainly want them to be comfortable.

But there are several considerations:

If the shoes are too short your toes will bump the ends, and this can become torturous 75 mile into a centurion.

On the other hand, if the shoes are loose your feet will slide back and forth.  Not only can this be painful, but it means that you will not have a steady foot on the pedal, but rather the relationship between the ball of your foot and the pedal's center will be constantly changing, resulting in poor pedaling (and some additional pain in the foot).


Gabe,  If you love the frame, and are willing to spend the money to keep it, start upgrading everything else.  Start with:

Wheels/tires - rotating mass will slow you down the most - go to aluminum wheels and thin/light tires size 23 or 25.

Bottom Crank - Once again rotating mass, you can get some hollow core cranks, and adjust the chainring sizes to the biggest you can push.  You can save a few grams by going to a compact crank versus a triple.

Shifters/derailleur(s) - get some aero shifters/brakes, and upgrade to a lighter front/rear derailleur.

Seat post, handlebars, stem - On an old raleigh, they are probably steel - you can get inexpensive aluminum replacements.

Seat - get rid of the OG heavy seat and get something more comfortable and lighter.

From expensive and most effective, to least expensive/effective, thats the list off the top of my head.

Good luck on your decision, and keep those old Raleighs going, they are great bikes :)


What method or algorithm is used for computing power curve on Strava?

From Strava Support:

  The Power Curve shows your best average power for time periods of 1 second up to the length of your ride. We search your entire ride and find these best efforts and you can compare them with your best efforts for your last 6 weeks, the current year, years in the past, or all-time!

  -- Using your Best Efforts Power Curve (Summit)

As you are already aware, your critical power (CP) is the maximal power you can sustain without fatigue for a very long period of time. CP is also sometimes defined as the maximal power produced over a finite time period (e.g., CP30 would be the maximal power you can sustain for 30 minutes). The Strava power curve  therefore gives a variety of CP values across an array of duration intervals.

In the past might have been done with lab experiments (e.g., you warm up, then do a maximal effort on a bike ergometer or on a power meter equipped bike for a series of set durations), where you would then infer intermediate points based on some type of interpolation or statistical model (e.g., Monod-Scherrer).

With continuous performance tracking (i.e., bike computer + power meter) this can be done empirically  by querying all data within a ride or over a period of time (e.g., last 6 weeks) to determine the maximal power over a set of differing time intervals. These independent queries are then used to build the power curve displayed.

The Strava Power curve, is therefore an empirical curve based on cherry picking your best efforts for a series of durations, dependent on context (i.e., current ride or past effort(s)).

If you never put in a hard effort for a given duration in your ride, or in the past, then the empirical curve will underrepresent (i.e., biased low) your actualized potential if you were to do a real maximal effort. That said, if you didn't put in an maximal effort over a given duration (e.g., a 5 minute interval) you will clearly see it in the power curve associated with the ride, as the curve at the 5 minute mark will be lower than your historical best.

What About Statistical Model Fitting?

Another possible way to generate the curve is to assume that the true power curve of the athlete (what you would like to estimate) follows a particular mathematical form (i.e., parametric) and estimate the parameters associated with that mathematical curve based on your observed values and some sort of objective function (i.e., likelihood).  The problem with this approach is that you have to get the form of the latent curve correct, which can be difficult as people do not have uniform abilities across differing timescales.

For example, some athletes may have very strong short-duration power (e.g., 30 second CP), but lousy long-duration (e.g., CP60, otherwise known as functional power threshold [FTP]). As such correct form of the parametric curve will depend on the athlete, making a generalized fit routine problematic.

There are of course other alternatives that are more flexible with regards to the shape of the curve. Some of these include fitting splines, general additive models, or kernal smoothing. These are all computationally expensive and come with their own set of assumptions and drawbacks.

Given the volume of available data, an empirically based curve is simpler and likely more robust.  You typically start fitting parametric statistical models when you are more data starved and each individual data point is more trustworthy.


Can't find the B-tension screw in rear derailleur

As other comments have stated some older derailleurs did not come with a "B" screw. This is also true of newer low end components.


This depends how much it was assembled before going into the box. I've had one bike that just needed the stem bolts to be loosened and the stem rotated, plus the pedals fitted (using tools provided). The one I bought recently needed a little more work but still only using tools you'd carry on the road plus a pedal spanner. That was a used bike, and had been dismantled just enough to go back in the box.

The seller should be able to tell you exactly what is required. It's well worth asking them.

Important things to be aware of:

Some bolts need to be done up to a specific torque.  On many bikes this can be quite roughly approximated but on carbon fibre and light alloy you shoudl really get a small adjustable torque wrench (sometimes sold as a torque screwdriver).  The parts should normally be marked when the torque matters.
The left pedal has a left-hand thread.  Double check that you've got the pedals the right way round, then grease the threads and do them up with your fingers for severalturns before finally tightening with a pedal spanner (a thin 15mm open-ended spanner)


Waterproof overshoes on Platform Pedals with pins

You're right that most cycling shoe covers are made for clipless and only have a small cutout for the cleat. They'd get shredded by walking too much or using platform pedals. You could use hiking gaiters instead.

Alternatively, these delightful DIY shoe covers are open on the bottom, waterproof, and made with things found around the house.


A pin punctured my tyre. Should I only replace the inner tube, or patch the outer, rubber tyre?

The size of the puncture really dictates whether a new tire is in order... that being said, if you patch your tube and inflate the tire (the one with the puncture) you want to make sure the tube is not exposed through the puncture hole.

If you need to ride and the tyre is questionable... an old trick is to put a dollar bill or power bar wrapper on the inside of the tire over the puncture hole... then install the tube and inflate.  The pressure from the inflated tube will be distributed across the wrapper resulting in an extra barrier keeping the tube from protruding.

Good Luck.


Can I jump from small heights on my bicycle?

Your bike is designed for riding on rough terrain, like forest trails, roots, take an occasional drop. It should not break after a few drops from low heights, if you apply the technique correctly. Of course, it will shorten its life, so if it becomes regular practice, you should switch your bike from entry level MTB to something more appropriate.

You might find stickers on your bike that it is not designed for racing, but just recreation usage. This may put limitations on warranty.


I have recently just done the same thing and switched from suspension to rigid forks, although with a much older bike. There are a few things that you need to know.

The first is your type of headset, it will either be threaded or threadless. If you have a stem that clamps on the steerer tube and then your handle bars clamp onto the stem, you have a threadless headset. I can tell by the picture you have linked too that you do have a threadless headset.

The second thing you need is the diameter of you headset, which is generally 1 1/8 inches for modern mountain bikes but if you can find a specs sheet for your headset it will specify. If you cant find the info for your headset, just measure the steerer tube with a set of calipers and look at this page (http://sheldonbrown.com/cribsheet-headsets.html) under "Threadless Headset / Steerers" and reference the measured dimension to identify the size of steerer tube.

Last, and probably most importantly, you will need to know the axle to crown measurement. This is basically the measurement from the middle of your front axle to the top of your forks. There is plenty of info on the internet on how to take this measurement but the important thing is sit on the bike and get someone else to measure or get a friend of similar size to sit on the bike while you do it, this will ensure the slack is taken out of the suspension. This measurement will help you to get forks that are a suitable replacement length for your current ones. This is important because your frame has been engineered to work with forks of a given length and altering that geometry by a significant amount will alter the handling characteristics of your bike.

One thing that can help make it easier to select forks is to buy models that have been specifically made as replacements for suspension forks with a given amount of travel. If you know the amount of travel of your current suspension you can buy some forks that are specifically made to compensate for that amount of travel (i.e surly instigator 1.0 forks are made to replace shocks with 100mm of travel). It is still worth checking that the axle to crown measurement is similar to your current setup as they can vary in size by manufacturer. For example my original forks (2002 Rock Shocks Judy C) originally only had 80mm of travel but they are relatively long and I needed the Surly instigators to get the correct length. (They work awesomely well, by the way).

When picking new forks also make sure that they have the correct brake mounting fixtures. You will often need to specify for disc, or cantilever, or both. When you get the forks, it is probably easiest to take them to your LBS and get them fitted as they will need to take the fork crown race off your current forks and move them onto the new ones. This is best done with specialist tools, you can do it yourself, but it is not worth risking the damage to components as the crown race is specific to your headset and you may be up for a new headset if you damage it.

Also make sure the new forks are made for your size of wheels, 26, 27.5 29 etc.


What is causing this chain clicking noise?

A couple of things I see:

I think your derailleur is a bit out of adjustment and is "leaning" towards the lower gears.  It's grabbing on the ramps of the lower gear as it goes by.
Your B screw adjustment is a bit too far away from the cassette.  I would try to get it within a link or link and half.  It looks from the video that you are about 2-3 links away.  See section 4 of this link: http://www.sheldonbrown.com/derailer-adjustment.html

Lastly, is it possible that 9 speed chain (or less) is on that 10 speed cassette?  If the chain is too wide, it would have the same symptoms (grabbing the ramps)


Which mountain bikes are purposefully built to be 27.5 and 29 compatible, similar to Rocky Mountain Pipeline

27.5x2.8 and 29x2.4 have approximately the same outside diameter of the inflated tire. Same with 27.5x3 and 29x2.5-6ish. All 27+ bikes can run 29; it's implicit whether they're marketed as such or not, although many are. In the other direction, bikes presented as native 29, there may not be enough side clearance for a 27+. Older 29ers would typically not have that kind of clearance to spare, but the whole 27+/29 interchangeability thing got big around 2016 and many made since then have it.


Bike making random noises after being lubricated

First, what you have is a bike with derailleur gears. The derailleur itself is the mechanism that moves the chain onto one of several sprockets mounted on the rear wheel hub to achieve different gear ratios. The sprockets can be referred to as a sprocket cluster. Many people also call it a cassette (although that properly refers to sprockets mounted in a particular way).

The sprockets themselves do not need lubricating, only the chain does. Excessive lubrication can be dangerous if oil gets on the tires, braking surfaces on the rims (or discs on new bikes) or brake pads. It also tends to make a nasty mess, getting on the frame, wheels, legs and clothing.

What I would do is give the bike a good clean, using a degreaser product to remove the excess oil on the sprockets and chain. There are decent citrus based ones available that work well and are not expensive. There are many Youtube videos out there that will show you how to properly clean a bike including the sprockets and chain (example below).

Buy some bicycle chain specific lubricant and re-lube the chain. Bike chain lube may seem expensive but it lasts a long time because you only need a drop on each joint in the chain.

From you description it's hard to say what's causing the noise, but it seems likely it's connected to the freewheel ratchet mechanism if it only occurs when freewheeling. I doubt it is due to excessive oil on the sprockets. If you are not mechanically inclined I'd have a good local bike repair shop check the rear wheel. Even if the noise isn't dangerous it's super annoying for a part to break on a ride and leave you stranded.


Carbon 700c Wheels: What does 33/50/60/88 mm refer to?

That dimension refers to the depth of the rim.  See this article on some particular carbon rims, that includes a cross-sectional diagram.  Deeper wheels tend to be more aerodynamic, though they are heavier, and handle worse in crosswinds.  Thus, different rim depths are more suitable for different types of races.  88mm rims are almost exclusively used in time trials and triathlons, while shallow rims will be more popular for races with lots of climbing.  For riders without the luxury of multiple wheelsets, 38-60mm seems to be the standard depth.

The life span of carbon rims (or any rim, for that matter) depends greatly on the type of riding done.  Typically, a wheel will need to be replaced because the braking surface has worn down.  This means that the wheel's longevity is dependent on the type of riding done.  Long descents with lots of braking will accelerate the wear.  Riding in the rain will accelerate the wear.  Keeping the brake pads and rims clean will increase the longevity.  Also, some carbon wheels have carbon braking surfaces, which are more sensitive, while others have aluminum braking surfaces, which are more durable.

So I am hesitant to give an exact number, but I'd say a reasonably-well maintained wheelset should probably last 10,000-20,000 miles.


Shimano road shifters have to be matched with road front derailleurs, and mountain shifters have to be matched with mountain front derailleurs (technically, you could use a pulley like a JTek Shiftmate, but thats a dumb solution due to price reasons). Theres no compatibility difference in the rear (update: see the comment - the following holds up to 9 speed between mountain and road), except mountain derailleurs are normally long cage and can take bigger cassettes (and thus are favorable in a touring context). Stick with one brand for shifters, front derailleur, rear derailleur (crossing brands is possible, but more complicated as there is no standard for how much cable shifters have to pull, and you may need pulleys to change the cable pull to get things to work).

Front derailleurs are normally also matched to if they are double and triple and are specified for what range of chainwheels they work most favorably with (you can find this on the data sheet for the front derailleur - this is less important with friction on the front, but brifters can be finicky). In choosing a front derailleur, you also should make sure that the front derailleur can be mounted on your frame and the cable pull is in the right direction for your frame.

The particular crankset you pick's compatibility will be determined by if you have a bottom bracket that matches it in the bike, along with if its a double/triple (matching the front derailleur) and within the appropriate tooth range and has appropriately sized tooth jumps. To quote Sheldon Brown (article linked later): "Shimano's "10-speed" triple front derailers are optimized for a 13 tooth difference, typically 52-39. Most other Shimano front triple derailers are optimized for a 10 tooth difference between middle and large ring.". The speeds on the front derailleur are marketing term - you don't really need to stick to them since the speeds are determined by whats in the back(but obviously, Shimano wants you sell you an entire groupset, and 10 speed systems use narrow chains, so you should have a 10 speed FD, 10 speed RD, 10 speed chain (you could use a lower speed FD, but it might not be as crisp) ).

I recommend reading this article for seeing what goes into selecting a front derailleur and this one as well.

In terms of price, the shifters will be the biggest expense and will determine the FD. Regarding the RD see the comments, so you don't need to worry about it. Once you pick the shifters, you can pick a relevant FD and crankset.

Also note that a 2x10 or 3x10 setup is pricey relative to many 2/3x8 or 2/3x9 systems- the chains don't come with master links by default (and are pricey), and since things are narrower, they can be more annoying. Will the extra 1 in the rear buy you anything? Probably not.


How to turn off Live Segments on Garmin Edge 520 for good

You can disable popular segments in Strava under Dashboard -> My Segments:

Then as long as you don't star any segments none will be synced to your device.


In general, when you see oddly shaped teeth or variations on a cassette/chainring, its there to facilitate shifting (such as Shimano Hyperglide, and ramps/pins you see on chainrings/cassettes; see this link for some examples).

In this case, SRAM calls it their "Open Glide" technology. To quote them:
"OpenGlide tooth ramping allows for faster chain transition between cog postions. We employ OG on the radical OG1090 cassette for sure and higher shift speeds."

And here is a figure SRAM provides:

The marketing blurb from Art's Cyclery says:
"SRAM's open glide technology refers to the shift gates created by removing teeth at key spots on the cogs to facilitate fast, effortless shifting going up or down or under power."

Whether it actually shifts better or not is a matter of debate, but a quick search says that generally not. I'd guess SRAM also found that to be the case, because they don't do this on cassettes in their current product line.


Why would the tension screw on a Brooks saddle have unscrewed to zero? What negative effects?

Checking the tension on a Brooks saddle is part of the regular maintainance. Any bolt that doesn't have sufficient tension on it will move due to random road vibration.

From

http://www.brooksengland.com/getting-in-touch/faqs/saddle_maintenance/

  Q: Why have the Rails / Tension Pin / Backplate on my Brooks saddle
  broken? By far the most common cause of breakages of the Rail,
  Backplate and Tension Pin is insufficient leather tension. Brooks
  recommend a routine six-monthly check of the tension, and adjustment
  where required.

A bolt stays in place due to the friction applied to the threads by the tension in the bolt. In effect you are "stretching" the bolt so it constantly pulls on the threads
to create the friction to hold the bolt in place. In the Brooks saddle case the force
is actually a compression, but the principal is the same.

As long as you put the tension back and check it on a regular basis, I don't think there should be any long term damage to the saddle.


No, this sounds like way too much play, even though the lock-ring is tight it  could be tightening up against the freehub and not the cassette. If you can wiggle the sprockets apart a bit, or slide them along the freehub then the cassette is not being held properly by the lockring. Then you just need to add some spacers. Shimano lock-rings should "click" loudly as you tighten them up usually. I install several a week and would be concerned if even the cheap ones had as much play as you mention.


Name of a certain modern rear-derailleur part at upper end of pivot

If it's the part I think you mean, Shimano label it as either the Bracket Axel Unit or the B-Axel depending on if it's the direct mount or standard mount variant.


Outside of Schrader valve is inflating. This isn’t right, is it?

I haven't come across this before but it's not right. It sounds like the valve coating is coming unstuck from the metal part of the valve. If that fails it would be quite likely to fail suddenly which could be painful. Time for a new tube


Advice on what to buy for someone who snaps rear axles often

You almost certainly have a 7 or 8 speed freewheel hub. They can do this, especially 8. Google those terms along with broken axles.
8 speed freewheel hubs had some years of prominence circa 2000-2001 and then were rejected by the industry because of these problems. They have now made a return due to manufacturers answering the pressure to fit so many other name features into a low price point. They're cynical trash.
If the above surmising is true, get a compatible cassette hub wheel and a cassette, plus a new chain.


How to tell if compression damping settings are working?

Try taking all the air out so you can feel just the damper’s resistance. Low speed compression will be noticeable when doing body movements such as preloading, weight shifting, or braking. High speed compression is for events such as hitting big drops and large square edge impacts. The easiest way to test that is to smash into a square curb (perhaps with a bit of air to prevent fork damage).
Remember that the “speed” here is shaft speed, not bike speed. Shaft speed is how fast the damper shaft is moving through the oil column. Smashing a curb at walking speed is a high shaft speed event, just as pumping through a compression at 40km/h is a low shaft speed event.


What are the advantages of having a aluminium frame?

I suppose you mean "apart from price"?

The other important differences are:

Lightness: Carbon is generally lighter, but not always.  It is possible to buy alu frames that are lighter than some carbon frames.
Comfort: Generally, alu bikes are stiffer and less comfortable than carbon bikes.
Strength: Simply, metal bends and carbon breaks, but both can be repaired equally successfully these days!
Price!!  Generally, like for like carbon frames will be more expensive.

The real questions is "will a carbon bike make a difference to YOU".


That's a freehub body.

Look on the hub for the model of hub you have, and then you can use that to find the appropriate freehub body model by looking at the documentation of the hub.


Why are my gears moving but my wheels not turning?

Inside your rear wheel is what is called a free hub. It has a ratcheting mechanism that allows you to pedal backwards while conversely engaging when you pedal forward so to transfer pedal force to the wheel. I've been stuck on a trail more than once due to a free hub failing to engage.

Unfortunately your free hub is generally not servicable. Depending on the quality of the wheel, it is sometimes cheaper to just buy a new wheel vs paying someone to re lace your existing one.

Other than a broken chain, which would be obvious, I don't know of anything else that would cause your wheel not to move when you pedal forward.

Cheers.


You can get in-line cable housing adjusters.

A pair is listed on http://www.sheldonbrown.com/harris/cable-hardware-brake.html, part CAH32. I think those are made by jagwire, and they should be available at virtually any bike shop.

edit: those inline adjusters are for derailleur cables only. Use this http://harriscyclery.net/product/qbp-mickey-cable-barrel-adjuster-1061.htm for brake cables. It goes in the cable stop. Being a QBP product, you should also be able to obtain those at virtually any local bike shop.


diference between 170mm 172mm 175mm crank arm length on road bike

Believe it or not in the range of lengths you are looking at there is very little scientific support for there being any real discernible differences in performance (both in absolute power and metabolic efficiency).  For the lengths you are considering I would suggest this is largely a personal preference choice.

Crank length and maximal power

If we are concerned about maximal power output,  there appears to be no significant difference for the crank length range commonly (Martin and Spirduso 2001). The study used 16 male cyclists were tested for maximal power across crank lengths of 120, 145,170,195, and 220mm.  Only the extreme (120, 220mm) showed a significantly lower maximal power, but the effect size is small (around 4%).

Figure 1 - Maximal power as a function of  crank length (reproduced from Martin and Spirduso (2001)).  Be careful of the Y-Axis scale, the effect size is actually small and error bars are large indicating a lot of individual variability.

Choosing a crank length for optimal power

Martin and Spirduso (2001) also attempted to create a formula for optimal crank length based on fitting a 2nd-order polynomial regressions to the subjects best power (response) as a function of the ratio of leg, tibia, and femur lengths to crank ratios (think inverse U cuvrve).  Leg and tibia lengths had support ($R^2$ of 20.5 and 21.1%), but the effect size was small (around  3%) and the relationship had a number of outliers.  That said, the regressions suggested a crank length that is 20% of your leg length or 41% of the tibia length.

As a side note, in terms of effect size, you can gain 5% through gear selection, using larger cogs (see Spicer, 2000).

Crank length and metabolic efficiency

Most cyclists are not producing maximal power on their ride.  Instead we tend to spend most of our time at sub-optimal output levels. In this case we might be more interested in the metabolic cost of cycling, and optimize the setup to be the most metabolically efficient. McDaniel et al 2002, investigated the impact of a number of factors (including crank length) on metabolic cost. 9 cyclists were used in the study.  A smaller number of crank lengths were used (145, 170, 195 mm) compared to Martin and Spirduso (2001).  Pedal rates were also investigated (40, 60, 80, 100 rpm).

Overall, mechanical power strongly predicted metabolic cost (R^2 = 0.95; not surprising) and the authors used the metabolism residuals (left over variability) to investigate the impact of crank lengths, pedal rates, and pedal speed.  The used step-wise regression to attempt to build the best descriptive model (personally I think small-sample sized corrected AIC ranking would have been more appropriate).  They found independently each had some descriptive power, but overall the best descriptor was pedal speed (combination of crank length and pedal rate (cadence)).  Once pedal speed was accounted for the other factors (e.g., crank length) provided little descriptive power. Note that all of these factors will be related (i.e., multicollinearity) so it is not surprising on their own there would be some descriptive power.

In terms of metabolic cost, it would seem your pedal speed is what matters.  To quote the author:

  The main finding of this investigation was that mechanical power
  output and pedal speed accounted for 99% of the variation in metabolic
  cost at intensities below LT.

Note that LT stands for Lactic Threshold (aka maximal aerobic capacity).  More importantly, they follow up and state (emphasis added):

  Mechanical power output alone accounted for 95% of the variation in
  metabolic cost, suggesting that, even with our wide range of
  pedaling rates, pedal speeds, and crank lengths, muscles’ ability to
  convert chemical energy to mechanical work was remarkably stable.

Choosing your length

The take home is our body will adapt to the commonly used crank lengths, so you need to select base on other factors. While some will argue that  performance gains are possible,  these for the most part appear to be small, on the order of small drive train efficiency gains (e.g., using larger rear cog; see Spicer, 2000).  A common theme to me is that individual variability seems to be a much larger effect, therefore you will need to consider your personal situation.

If I had to suggest one potential selection criteria I would suggest considering if you like to spin or mash your gears.  If you like to spin, you will likely want a shorter crank length so you can turn your legs over faster.  If you like to mash, a longer crank length will likely feel better as you have more leverage.   As an aside, spinning can also be more efficient as you tend to use a larger cog in the back, which is known to be more efficient (Spicer, 2000). Why on earth modern cassettes use such small cogs I have no idea! I suspect weight at the cost of efficiency.

Other SE questions covering this subject.

What is the effect of changing length of crank arms?
Why such a tiny difference in crankarm length?

External Reading

A good summary of the science, in a readable format, is available on the Cervelo website:

http://www.cervelo.com/en/engineering/ask-the-engineers/crank-length.html


MTB freewheel not moving back wheel after change of tyre

Halfords Apollo 7 speed bike, likely has a freewheel unit screwed onto the hub. For this repair that would be beneficial in its simplicity.

As the rear cogs are turning, while the wheel does not and you can pedal freely, it seems the freewheel has stopped working. It is not cost effective to try and repair this because replacements are so cheap, so you need to replace the freewheel with a similar spec - temporary workarounds exist. You'll want to know that it is seven speed (check) and then the number of teeth on the smallest cog and the largest cog of the freewheel. Maybe something like "11-28" or "14-28" -  you just need to count them or look for a model code yours. Most freewheels you come across now, with the age of your bike, are standardised enough that you can buy any matching spec you come across, touch wood.

Replacing a freewheel instructions are easy to find, or you might be able to find a shop open at the moment... Not guaranteed! There is (naturally)  a very good page on Park Tool's website here.

If it happens to be a freehub design then it's the freehub of the wheel that needs replacing to achieve the same fix, which is a little bit more involved but instructions should be simple to find. The harder aspect would be finding a freehub that matches your existing one, designs vary more, and the way to find it out is by dismantling the wheel some.


Having just one bolt to bear the load isn't enough. The main good option would be to replace the stem. It's chunky so helicoiling would likely also be fine if you found a shop to do it cheaply enough.


how is the middle of a folded Brompton supported?

From a phyics or engineering point of view, I don't know, something on the order of 20/30 kgs, maybe?
From the warranty and manufacturer recommendation, the answer is 0.
A folded Brompton (and other foldable bicycles) are not supposed nor meant to carry any weight.
You can still revert the order on your trailer, put the heavy stuff on the bottom (which is  in any case a meaningful thing to do) and then the Brompton on top, fixed with some bungee rope or with some other kind of band/belt.


Is 2kg static cross-load dangerous for a carbon frame?

Opinion, but a frame bag won't cause any problem for a normal bike frame.  If it were an ultralight hillclimbing bike with no paint or something specialist, then I'd worry.
If you're concerned about fretting of straps on the clear coat, get some of those clear frame-protection stickers and apply to the frame under any retention straps for your bag.  Also cinch velcro straps down firmly.


Why is it important to keep bearing sets when greasing a campagnolo hub?

In almost all cases when servicing a hub the bearing DO need to be replaced.

You may not be able to see it without the aid of a microscope, but the bearings will be slightly pitted after any appreciable period of use. As one user points out, high grade ballbearings in case hardened steel, even grade 25s are very cheap - why cut the corner?

Case hardened are preferred as they are less brittle, BTW.

Bear in mind that in correct bearing design, as it's difficult to get an exactly consistent rate of wear on the three components, you will generally find that the balls (being the cheapest and easiest to replace part in the assembly) will wear first. Then the cones. Last will be the internal bearing surfaces (in the case of the hub) as these are the most difficult to replace. Cones and cup wear rates may be the other way around if the cone is integrated with another component or part of the assembly that is difficult to access or change - not normally the case in any conventional cycle application.


Is it normal to have some soreness in your knees after cycling with SPD?

If your bike is set up with a proper fit to your body, and your pedal's cleat position is set up for your body, soreness in your knees like you describe is not normal.

Whether the discomfort you are experiencing is simply muscle soreness, as in "I exercised heavily and my body noticed" or whether it requires corrective action, is harder to decide.

If the discomfort is only after heavy exercise, like 40+ km rides in a headwind, I'd be inclined to say its because the pedals are new to you, and you're building the muscle you need to use them, as your body adapts to pulling up, not just pushing down on the pedal.

However, if this continues to be an issue for more than a few weeks, consider having a bike fit done which includes cleat positioning.

Also, if you are not riding off road, and you have purchased mountain bike style SPDs, rather than the road version, consider getting the larger and more supportive version. Unfortunately, this would usually also require new shoes, but many riders report cramps, hot spots, and muscle soreness when riding longer, uninterrupted distances on MTB clipless pedal designs.


This frame is manufactured by Giant.  The G0583 is a date code from Giant.  The serial number is on the other dropout.
Giant was contracted to make frames for many brand names in 1983.


Any good 18 speed gear shifters for drop handlebars?

You have several options:

integrated shifter/brake units (brifters) which are modern road bike style.

bar end shifters. These are not brakes

Downtube shifters - these would be common on bikes from the 70s and early 80s.

Stem shifters - a relocated downtube shifter, mid 80s to early 90s.  Image is a single, but duals were common.

rotary - this one I've never seen.  It appears to be a MTB style "web-of-thumb" rotary control on a bracket mounted to the stem.   Could be unique to Rolhoff IGH.

Another option is to not go to drop bars, but to shorten your existing flat bars.  Its cheaper, but you won't get the variety of hand positions that a drop bar will give.  Its also impossible to revert, once you've cut some off there's no going back.  However you can use the existing controls, just shuffled inward a bit.

Any gear lever system you get will be either indexed or friction.  If its indexed, it has to support the number of cogs on that end of the bike, probably 3 for the front chainring / left hand shifter, and 6 for the rear / right hand shifter.

If you chose a friction shifter, then its up to the rider to get the chain into the right place, and then friction holds the lever.  Bar end shifters are often friction based.  Brifters are always indexed.

Please do let us know what you ended up doing.

EDIT OJS makes an excellent point - road brake levers for caliper brakes than V-brake or a centerpull brake or a cantilevered brake; they will require more cable pulled than a caliper brake.  So you may be fitting rim caliper brakes to your conversion as well.  Does the frame have mounting holes straight over the tyre?

If you have hydraulic disk brakes, then this is getting really expensive quite quickly.  Cable-operated disk brakes may or may not work with road brake levers... the cable pulled to activate them must be the same as the flat-bar brake levers.

So my suggestion is - don't.  Look for a road bike that is like your requirements, and buy it.  The red one in the first image is my bike, which cost $123 NZ.  So I have a MTB still for towing the trailer or for wet weather or for biking on anything a little rough.   Remember, N+1 is the correct number of bicycles to own.


Ask the guys you ride with and also complete strangers you meet on the trail, what they use and why. My guess is 9/10 times it was on the bike already, or it was on special.

I have ridden for years, have a range of tires I have tried. Some I have liked better than others, mostly its a trade between speed, traction for braking and acceleration (not my strongest point anyway) and cornering.

A tire is a compromise of the following

weight
cost
Straight line performance (one and/or both directions)
Cornering (Predictability and maximums)
Puncture resistance

Add to this the types of terrain being ridden (the list gets bigger)

Rock
Dirt
Sand (soft)
Hard pack
Pavement

Then add

Wet
Dry

If you are a casual weekend warrior like me, you got to the LBS, ask them for a tire for the trails you regularly ride (which they should know) and hope they gave you something half decent.


What are the good ways to maintain the bicycle while raining season?

Use fenders with good coverage! They will keep most of the dirty spray water off your bike. You'll be surprised how much less oiling your chain needs with proper fenders.

Proper fenders means:

a front fender with a mud flap that reaches within a few centimeters of the road
a rear fender that starts some centimeters below the chain stays, so that water dripping off does not end up on the chain


No, that's a BB386EVO bottom bracket. There is no way to do this with a normal BB30 crank because the spindle isn't long enough.

BB386EVO cranks are 30mm spindle cranks with longer spindles that can go in both BB30 frames and threaded shell frames with BBs such as the ones you link to.


Difference between "Track Frame set" and a "TimeTrial/Triathalon frame set"

You seem like you want three different bikes all smashed up into one, and the result is not going to be good.

First, the time trial frame is not intended to be a track frame. If you're going to race at the track, use a frame and components that are designed for the track. For starters, the time trial frame will have a lower bottom bracket, dramatically increasing your likelihood of a pedal strike, which can be disastrous.

Second, bikes at the velodrome are not allowed to have brakes. Period. You will also likely not even be able to mount brakes on the Planet X Track frame.

Third, a belt drive won't really improve the reliability of a track bike. Track bikes use significantly thicker chains due to not having to fit between tightly-packed cogs in a rear cassette. Having raced a few years at velodromes, I have yet to see anyone snap a chain.

Fourth, you probably won't even be able to install a belt drive. Belts can't be disconnected/reconnected like chains can, so you will have no way to route the belt through the frame to mount it around the chainring and cog.

Fifth, aero bars are explicitly disallowed from any mass-start events at the velodrome. Unless you only plan on riding pursuits, you will need standard drop handlebars.

My advice? Save the creativity for your second bike. The fact that you have to ask this question tells me it's probably your first build, and you're very likely to end up with a frankenbike that's not actually what you were hoping, not race legal, and likely not even possible to build given the requirements / parts you've named.


How to avoid hand strain when landing with a road bike?

I used to experience this when I switched from doing a lot of mountain biking to BMX - you really have to learn precisely how to absorb the impact. I thought I was doing it right until I no longer had a suspension fork. Simply absorbing with your legs isn't all there is to it.

You want to land flat and carefully set the bike down. What I mean by that is extending your limbs - just like suspension travel on a full suspension bike would extend once airborne. As you land, the bike needs to touch down the front and rear wheel simultaneously, or ever so slightly tail heavy (touch much and it will slap the front down though, and that's no good!) And the moment before impact your should already initiate absorbing the impact; this is the "careful set down" part. As for the absorption part, we're talking 95% in the legs. Get your weight back. The picture below really shows what I mean. If your weight is way back, the front wont impact as hard. Yes, the rider would've landed very tail heavy to absorb the initial impact of a drop of that magnitude, but the point here is shifting your weight back. His hands/arms are not in a position to absorb much of anything, rather, they're a pivot in the suspension system that is his body.

Of course, you've always got the disadvantage of the road bike geometry and proper riding position. But, you can also see in the photo how much space is available in the cavity between the rider's body and the frame. There's plenty of space for a road frame in there!

Hope this helps you!


It looks a lot like this Bianchi / Nealeco

Apparently this style folding frame was quite popular in Europe during the 1970s - many small boutique bike companies imported them [from Yugoslavia?], slapped their own identifying marks (decals) on them and sold them to their urban, and urbane, clientele. At least that is what I have read about them.
CLR Effect

Here's a 12 inch wheel version in not quite Bianchi green
The chain stays and rear dropouts are a little different

It also looks like this Chiorda Safari

Slender Fungus Cycling Association

The brand is Chiorda and it is a old italian bike. They made a high end road bike ridden by the famous Felice Gimondi. The company was later bought out by Bianchi who also bought out the Famous Legnano.

It looks like there were various wheel sizes with various brand stickers on this bike over the years.


Best setup for lightweight cycle touring with Ti road bike

I would avoid a trailer.

On rear rack you are going to have heel clearance issues.

It may seem extreme but get a front fork with braze-ons.  Braze-on on the inside and outside for really solid rack mounting - check out the Salsa Vaya.  Not going to cost you more than a trailer and ride a lot nicer.

Also consider frame bags. Check out http://www.revelatedesigns.com/. See this set up http://moots.com/our-bike/cross/routt-45/overview/. You can put water bottle cages on the axles.


Freshly inserted pin on a new Shimano chain causes a stiff joint

It happened to me several times and the most reliable way to fix it was to actually push the pin back a bit, i.e. use the breaker tool from the opposite side engaging the chain link on the other bits of the breaker tool, see the picture:

Red is the chain breaking tool
Black are the chain parts
Blue is the pin you are driving in

First you drive the pin (usually from the outside towards the frame) just to see it flush like the other pins on the frame side (middle figure). Since the whole link was resting against the massive part of the breaking tool, it gets somewhat compressed (towards the frame).
You then reposition the chain breaker tool so the chain link rests on the tiny leaves of the breaker tool (see the right-most figure) and drive the pin further relieving the link.

I've found a youtube video titled Bike Assembly and Repair - Chain Breaker Tool that shows the whole process as I've described it above.


What are the safety concerns of a high vs a low mount trailer hitch?

The higher the hitch the easier it is for the trailer to push the bike sideways or lift the rear wheel of the bike under braking.

With the high hitch you can generally only do one of turning and braking at a time. So if there's a problem and you need to swerve and brake to avoid it, you will end up lying on the road with a canoe on top of you. And a bicycle. And a trailer. And they will all still be moving.

The solution is to disconnect the rear brake of the bicycle and use that lever to operate the the trailer brake, but few people do that because it's not trivial and in practice it's not really necessary. Most people find that the "tow my canoe" rig is big, heavy and unwieldly, so they only actually tow for short distances on flat ground. That makes riding slowly and carefully quite practical, and often they can choose quiet streets as well.

One other option is a three or four wheel trailer which you could do as a rear dolly and a front, pivoting pair of wheels. Handling will be better than a central dolly if you can work out how to attach the front solidly to the canoe. Or have a spine to the trailer.

This question is much more important for touring trailers and work trailers, where the distances covered are greater and there are fewer opportunities to avoid bad roads. That means the consequences of a crash are more severe as well. But at the point where you're building a trailer with brakes and suspension (because there are 4 wheels) it becomes worthwhile modifying the towing vehicle as well. Most people start down that path and end up with with a trike as the load vehicle or the towing vehicle, or a quad bike. It's much simpler to build and ride a single vehicle than a trailer.

Answers like this Burning Man Trailer one deal with the general details of heavily loaded trailers. It's also worth mentioning Richard Guy Briggs and his canoe carrying tricycle


How much does non-ideal frame size matter?

First, note that frame sizes aren't standard - you may ride a 55cm in one model, but a 52cm in another model (say, comparing road racers to cross bikes). And, you do pick your model based on preference - I prefer a larger bike than most people of my height, since I have relatively long legs and long arms.

Most of the time, you can go about 1 frame size above or below the ideal frame size (thats around +/- 2 cm in model numbers, typically ) with part tweaking - the most important measure being top tube length, which can be drastically different between similarly labeled models (This can be offset with saddle and stem replacements to some extent, but the adjustment ability is relatively limited). This is why getting good bike fit is important (and why people have to try bikes before buying them) - the geometry chart isn't super useful unless you know how that chart fits you (and some relevant swappable parts like saddles come into play as well). Of course, you have to be careful with this, especially for bikes which will be used off road (you wouldn't want to hit the wedding jewels on the top tube for example).

This is a good article on the topic of frame sizing.

For what its worth, if I had to intuitively place a 55cm, 60cm, and 50 cm road bike, for males, I'd guess a 50cm being for people closer to 5'2" ish, 55cm for people closer to 5'6", and 60 cm for people who are probably 6'1" ish. But again, this is completely useless without trying the bike.

To add, most likely, a wrong frame size (or misadjusted frame) will lead to back pain or knee pain. Both are not fun to deal with once you're past being a teenager.


It mostly depends on the thickness of the tube.

Chainstays and seat stays tend to be quite small tube, so drilling them takes a larger percentage of metal away.  I would not drill a stay unless I had a welder to add metal- instead I'd use a clamp-on fitting.

For downtubes and seat tubes, the tube itself tends to be wider.  I've successfully used a nutsert or rivnut to add bidon mounts to a steel road bike.  This involved careful drilling, then using a special tool to mount and crimp a special insert into the frame.


Are Shimano jockey wheels compatible between groupsets, provided same speeds?

They are often compatible between different companies. Certainly between different groupsets of the same companies. The manufacturer normally states where they can be used and often that is multiple systems (like both Shimano and Campagnolo, some provided spacers may need to be used and may only work for some range of speed counts). Of course, if you buy a Shimano product, they will tell you it is for Shimano only. 10 speed Shimano should be compatible with other 10 speed Shimano.

But before replacing the wheels, I would try to service the current ones. I think 105 generally has pulley wheels with bushings. They can be easily services and likely need that more often than pulley wheels with bearings. How to do that is in the video below

You can of course consider ceramic bearings but the jump from bushings to any sealed bearings is likely more important than the jump from metalic bearings to ceramic bearings.


Which option; cx bike or mtb and road bike?

I want a bike that will allow to me ride on the road and on the rough trails

I guess we can't be sure what you mean by "rough trails", but if you're talking about what I call "rough trails", a CX bike just isn't going to do it.

  i don't want the relaxed geometry. I want to go fast.

Relaxed geometry and high speed often go together off-road (think DH bikes).

On the road, a $1200 CX is not going to be as good as a $800 roadie, but that's only because of the knobby tires.

I think your best option is the road-mountain combo.

If you wanted one bike to do both jobs, I think a mountain bike with ~1.75" semi-slicks would be better than a CX. Plus, that won't cost you $1200.

A side note: No matter what you end up getting, you should buy used. You'll get much more bike for your money.


Pretty much all front and rear lights, except very cheap and simple ones, have a flashing or pulsing mode. Some have a harsh, strobe-like flashing, some have a softer pulsing effect.

Running a front light in flashing mode is good for daytime use where you need to be visible.

Flashing mode is horrible if you need to see where you are going at night. If you want to run a flasher at night, get a small additional light in addition to a main light that has a decent main beam.


Can you open the trunk with the Saris Bones 2 trunk rack attached?

I have a different Saris rack that has one top foot and two lower feet like the one you show, but I didn't find it on their website now.  It has six straps, two top, two side, and two bottom.  I use it on the hatch of a Lexus CT200h, same as Prius C.  The lower feet sit on the bumper for me, not on the hatch.  I can open the hatch when no bikes are installed with no problem.  In fact, I open the hatch to install the rack because the side and bottom clips are hard to get on with the hatch closed.  I had a previous Thule rack with the same experience except that you have to keep your head out of the way when closing the hatch.  All the feet of that one sat on the hatch.


Brake lever compatibility between disc and v brake

It should work. They both require the same amount of cable pull.


@Michal,  I can't be certain from your picture, but your fork looks a lot like mine.  If it's the same kind of design, then the caps are simply plastic plugs, not threaded, simply friction-fit into the openings.

Here's a picture of the cap area of my fork.

If mine were missing I'd do just what @RoboKaren said, either make a plug out of a genuine cork champagne cork or maybe one of the plastic ones or (probably what I'd do) just duct tape over the area after cleaning the area with soapy water then mineral spirits to remove all surface contaminants and make sure the tape sticks.  You can get black duct tape if you want it to blend in.

BTW I'm assuming my suspension fork uses elastomer "springs" for the shock-absorbing effect, but I'm not positive because I've never been inside.


Can my cantilever brake pads not being centered lead to a problem?

On rim brake calipers the cable pulls the two sides towards each other to 'pinch' the rim. If one pad contacts the rim first it will not exert any significant force until the opposite pad contacts the rim.

Centering the calipers allows the distance between the pads and rim to be minimized, thereby reducing the distance the lever has to be moved before braking force starts to be exerted.