Is a "universal" rotor compatible with all types of disc pads?

Every brake manufacturer recommends only using their own rotors, so this is another case where the answer depends very much on who you ask.
In general, here is where rotor cross-compatibility can go wrong:

Some inexpensive Shimano rotors have less hardening and are designated "resin only." They in fact wear very fast if a metallic or semi-metallic pad is used.
Magura rotors are 2mm thick and more or less everyone else's are 1.8mm. Using a thicker rotor than a caliper is designed around, along with unworn pads, could get you into situations where you don't have enough air gap to play with even with the pistons all the way in. Such issues come up rarely in practice however.
Different calipers can place the size and location of the pad contact patch on the rotor a little differently. It seems like in practice there is not a ton of variance, but there is some. Someone trying to design a universal rotor would be trying to make it big enough that the top of the pad on any caliper never overhangs the rotor, but the top of the rotor can never interfere with any caliper.

The main question with the idea of a universal rotor design is whether, given an on-spec location of the brake mounts, is there a magic number for the exact outside diameter needed in the last point. I don't know the answer to that. But for practical purposes, all of the above issues are rare, most rotors are designed to capture some aftermarket sales as generic repair parts, and it's all pretty cross-compatible as long as it's not resin-only or Magura.


No, it is not. Different bikes in the same class (mountain, cross, road, etc.) may even have different bottom bracket heights even among comparably sized bikes. It is a per manufacturer design decision where to place the bottom bracket.

Mountain bikes need higher bottom brackets to clear obstacles vs road bikes or cross bikes, for example.


Is there an easy to use app for tracking my cycling performance? (iOS or Android)

There are many apps available for iOS and Android. Some of the big names:

Strava
EndoMondo
Runkeeper
MapMyRide
Sports Tracker

They all have a mobile application that tracks your ride and then uploads it to a central server, accessible via a website. The website often provides reports and breakdowns of your performance.

They also add elevation data, but I'm not sure how accurate it is.

Additional performance metrics can be added through the use of ANT+ compatible devices to allow monitoring speed, cadence, heart rate and many more metrics.

My personal favorite, having evaluated all of them, is Strava. It is free, has a unique feature of tracking "Segments" of your ride, where you can see your performance for shorter stretches of your overall ride, relative to your past performance and also to other riders.

See also:

What is a good iphone app for bikers
What map / navigation / bike direction apps are available for the iphone for commuting / urban cycling
Bicycling apps for Android [closed]


Yes - this is a known way to get stubby aerobars on a flatbar MTB, that don't stick out too far but provide some benefits of an aero position.
Downside is that you generally can't have brake levers, so your hands are a long  way from the brakes. This is definitely not for urban riding of any sort.
Likewise, you're further from the gear shifters.  Okay if you settle into a gear and stay there for a while, but not good in undulating roads.
Lastly remember that since your hands are closer together, there's less fine-control.  So to start with it will feel very squirrely, and crosswinds can have a much larger effect before you can recover.  Over-compensating is possible too.
Upshot: this is great if you have a long open road in your commute on a MTB, or if you have a gravel fire trail/track.

Normally these "Bar Mids" (instead of Bar Ends) would be attached to the bar inboard of your grips, brakes, and shifters.  So all that has to come off the bars first.
If you do races on this bike, remember that many disallow the use of bar ends, so bar mids might be disallowed in the event.


Where can I get a basic toolkit for bicycle - Walmart etc?

You can easily find a "bicycle multitool"/"multi bicycle tool"/"bike multifunction tool" that covers all the basic essentials in one tool. There's tons of brands and models and what's most readily available may vary regionally, but common brands I've seen are: Park, Crank Brothers, Topeak, Serfas.

Where? I would go to my local bicycle shop to get them, or there's plenty of places you can order them online. I have no idea what Walmart stocks.  REI, Amazon.com, jensonusa.com, etc.  The only place recommendation I'd go with is: your local bike shop, that's owned by people into bicycles and primarily sells bicycles; they're bound to have some tools for sale.

Tools

Screwdrivers - both straight/standard/slot and philips.  You probably already have some.
Hex Keys (Metric) - (drivers, bits for a driver, whatever...). Also called "Allen keys", "hex keys", "hex driver", etc. 3-8mm range, typically, but you might need 1.5mm, 2mm, and/or 2.5mm. Most of the bolts on a bicycle are hex, and they're always metric.  It's likely that adjusting your brakes, for instance, requires a very small hex bit, swapping your water bottle cage a more medium sized hex bit, and adjusting your seat a larger hex bit.  L-shaped ones where the long end has a "ball" version of the hex and the short end is straight are nice; the ball lets you work at awkward angles and when the short side is used you get more leverage.  There's also some nice Y-shaped ones with 3 different sizes that I see used a lot.  The exact sizes will depend on your bike and components.
Maybe Torx - it's unlikely but possible that there's Torx somewhere on your bike.  Apparently they're common on disc brakes.
Tire Levers - these are usually plastic (nylon), and are used to remove your tire from the wheel so that you can repair flats.  Commonly sold in sets of 3.  Experienced people can get a tire off with just one, but it's easiest if you have three.  2-10USD for a set.
Pump - A floor pump and a portable pump on the bike is great.  There's two kinds of valves, make sure your pump works with your valves. Many pumps can convert between them.  The floor pump is for when you're working on things at home, the portable pump you take on the bike (along with tire levers and patch kit or a spare tube), because a floor pump is much easier to use than any portable pump.
Rags - an old rag or two, for grasping very greasy parts, wiping off the chain after lubricating it, etc.  Cotton is good, and preferably fairly smooth (not an old terrycloth towel; the loops snag).

Except for the pump and rags, a typical bicycle multitool will have all those and cost between 20USD and 40USD.  A "standalone" version of each tool will almost always be better than what's included in a multitool, but more expensive to get a whole set.  However, you can get a decent set of hex keys for under 10USD and tire levers for 5USD and still be a bit cheaper than a multitool.

Consumables

Chain Lube - only need a very small bottle, and usually the bottle has a tip you can use to apply the lube without using another tool.  Make sure it's a lubricant intended for use on bicycle chains.  In particular, WD-40 is no good for this. Obviously not included in a multitool, generally 3-10USD for a small amount.
Flat repair kit - This is a little kit costing under 5USD (they're a common giveaway item, even) for fixing holes in a tube (the thing inside the tire that holds the air). Generally a small amount of sandpaper or sort of metal file is included in the kit. There's self-adhesive patches, but I find the ones that have a separate tube of glue work better. Usually instructions are included.
Spare tubes - The patches eventually give out, so you'll want a spare tube or two.

Really, I think that covers the basics.  You might also consider:

Less important / Less "basic"

Spoke wrench - to adjust the spokes if they're loose, etc.  Also needed if you have to replace a spoke.  If you think you'll have to replace spokes, you may also need a chain whip and a tool for removing the rear gears, but the specifics will depend on your bike and that's getting a bit beyond "basic". Truing a wheel (making it straight and perfect) without a truing stand is tricky and a truing stand is definitely beyond a "basic" toolkit.
Tire boot - bit of rubber to patch the tire if you have a big gash in the tire. However, punctures (which generally don't require a boot) are more common than gashes, and you can make a makeshift boot out of all sorts of things, such as a $1 bill.
Chain tool - for makeshift chain repairs.  Usually chain problems mean you should replace the chain, but if you're out on the road and your chain breaks, you can remove a link and reconnect your chain (shorter) and make it home (avoiding the bigger gears until the chain is replaced)
Hex sockets - (metric, under 10mm).  Less common on bikes, and another item people already commonly have, but you may need both "genders" of hexagonal wrench.  On my own bike, I've used this on the fenders and not much else. Open or box is fine, and thin is probably fine, too.


The frame damage is more cosmetic I could tell from the pictures. The quick release can be replaced at low cost. The bigger problem could be to take it out because the end of the thread looks bend and damaged. Best go to your LBS (local bike shop).


bike for surfing: hybrid vs beach cruiser vs fat

All of those bikes would be fine, at least for a while. You can find pictures of board carriers on all those bikes.

The problem is that salt water destroys bikes. It's why beach cruisers are as cheap and simple as possible, if they actually get used by the ocean they will either require washing or rust out in a year or so.

A Fat bike would be a really good choice if riding on the beach itself is part of your plans. You can't really ride a beach cruiser in deep soft sand. However, fat bikes are more expensive and you'll need to be diligent about washing the bike if you want to keep your investment. Theft is also an issue, fat bikes are more likely to be stolen than a cheap rusty beach cruiser.


Presta's main benefit is more about how the valve functions, in regards to getting pumped up to higher pressures.  Because the stem of the valve needs pressure in the pump head to get high enough before it pushes the valve stem in, and start flowing air into the tire, when you try to get to 120 to 160 lbs of pressure it works better than a Schrader valve where the valve stem is depressed the whole time, back pressure can leak out.

Otherwise I would say tomato - tomahto (potato - potaato?)


suggestions of affordable clothes for beginner rides?

For a beginner, as long as all the required naughty bits are covered, and you're comfortable standing and walking in those clothes, then they're generally fine for cycling.

A beginner is anyone tootling 3 kilometres/2 miles each way.  If you're regularly doing rides of 16 km/10 miles then that's about where cycling clothing will come in handy.

There's no need to go silly with race gear.

The first specialist items to consider are

Padded pants or shorts or bibs  like http://www.dx.com/p/top-cycling-cycling-silicone-cushion-underpants-for-men-black-l-258557#.VnPkpW_4ugo for $10 US or bibs like  http://www.dx.com/p/2012-bike-bicycle-cycling-padded-bib-shorts-black-size-xl-125561#.VnPioW_4ugo   You're after something between your backside and the seat, and ideally pants to give some compression on your knees.
High visibility top (NOT BLACK!) like http://www.dx.com/s/NJ600  Under $20 US  or http://www.dx.com/p/spakct-stylish-sleeveless-cycling-jersey-t-shirt-fluorescence-green-l-227832#.VnPknG_4ugo
Gloves, I just wear $2 white gardening gloves from the local hardware shop.

I have bought all these things and they work fine for me.  My longest ride was last weekend were I did 118 km.

Other than that, check this site for "what tools to carry on a ride" and nutrition/hydration questions.  However that's bike gear not clothing so only a brief reference.


max weight that the shimano Rs400 can carry ?

Shimano RS400 is pretty old now - I know my 1998 frame had the wheelset new.

Here's a photo of my rear hub.  I can't show the front hub because that was replaced with an WH-R560 by a previous owner.   Why it was replaced, I don't know - it was either a speed optimisation or a failure where a new wheel was better than fixing the original.

Generally speaking, touring wheels are built for strength not speed.  So touring wheels should be at least 32 spokes on the front and more would not be bad.


What is the use of GPS/Elevation on Bike computers

Ever had that "this has to.... be the top.... oh sh$%.... it's a crest.... there's more...." feeling. Knowing altitude lets you pace your climb and arrive the the top without over (or under) doing it.

Imagine riding flat roads without knowing speed or distance - it can be done, but to maximize training effort or race performance you need to know speed/distance on the flat and altitude/climb rate on the hills.


Why is my big chainring is so scratched form the inside?

Some damage is to be expected caused by upshifts, that said, anecdotally speaking (i.e., based on personal experience), that amount of damage looks excessive.

Speculation

I wonder if the front derailleur was misadjusted so that it could be in the upper position, but not far enough for the chain to properly catch and upshift.  If the derailleur was left in the upper position the chain could partially catch then drop back down to the lower ring.  If ignored and ridden in that position over many, many miles the chain would continual catch and drop, wearing the inner side of the ring.

In terms of upshift functionality, all that really matters is whether the ramps and pins remain functional.  That is hard to assess from the photo (although I see some intact pins).

Next Steps

The best thing to do is make sure that the front derailleur is adjusted properly.  If the upshifts are still acceptable, then don't worry about the damage as it would be largely superficial in this case (i.e., the pins and ramps can still do their job). If you cannot get it to upshift reasonably well then you should look at replacing the affected ring(s).

Finally, with that much wear it is also worth taking a look at the teeth profile the teeth themselves are excessively worn, such that a new chain may skip.  This would be a different problem than the inner surface wear discussed here.

See: Does this chainring need to be replaced?


22 inch frame mountain bike for someone who is 5'8"

Bottom line:
If the choice is between buying a bike that is too large or waiting for the right sized bike then the best choice is to wait.

Much has been asked and answered on this topic on Bicycles Stack Exchange:
How can I tell if the size of a bike is right for me?
Choosing the right bike size
Riding wrong size frame

  Would this be unsafe/unpleasant enough that I shouldn't get it? Hard to say no to a deal like this!

It's a lot like shoes.

Let's say a size 8 shoe is the correct size for you.
There is a really great deal on an amazing shoe but all they have is size 10.

Would you wear a shoe that's two sizes too big?

Can you wear a size 10?
Yes, you can. Anyone who's had to live with the wrong size shoe will be reluctant to do it again. If it was a matter of wearing a shoe two sizes too big or walking through glass barefoot then it might make sense to get the size 10 shoes.

How "unsafe/unpleasant" would it be?
Only you can answer this question because you are the only one who can judge your unsafe / unpleasant level.

The Correct Size

There are good reasons to get the right size bike:
- Comfort
- Injury Avoidance
- Safety

According to a bicycling.com article the ideal size mountain bike for someone 5'8" is 17" to 18" or "Medium"

22" is two sizes too big.

According to the linked article:

  “Investing in a bike fit not only ensures you are going to get the right bike, but you’re also going to be set up on it perfectly, avoiding injury, pain, and discomfort, which will make cycling even more enjoyable than it already is,” Erickson says.

What ever you decide - always test ride a bike before buying.


Bar diameter for Genesis Croix de fer 20 (2015)

Thanks to renesis and Batman, I used masking tape to measure bar clamping circumference.

100mm circumference => 31.8mm diameter.


What do you do when a bus stops in front of you?

The Highway Code comes in handy with this question...

In London drivers of all buses are exceptionally well trained and likely to be highly experienced. They know every part of their route and have 'dealt with' plenty of cyclists before. They will always indicate when they are pulling over and indicate again when they are going to pull out. It is highly unlikely that you will be in their 'blind spot' at any stage of your overtaking manoeuvre.

It all depends on the traffic situation, how much speed you have and how important your journey is. Sometimes you can look through the back of the bus and see how many people are to dismount/catch the bus - if the stop looks like a busy one then you should overtake the bus, in part this is to clarify your intentions to road users behind you that may be 'waiting' for you to overtake before they do likewise. Conversely, if the bus is only dropping off one person, and, if the terrain does not suit you, then it can be advantageous to let the bus go, to 'draft' it and get a good, maintainable tow along the road.

Some bus stops, e.g. on a narrow road with a curve to the left may not allow you to see the oncoming traffic. It may be advisable to hold back in these situations, even if the traffic coming the other way is bumper to bumper. This is because a motorbike or other cyclist may be using the gap between the bus and the cars coming the other way and, once you have committed to overtaking the bus, you cannot duck in to the side again.

There is the Highway Code and you are supposed to let bus drivers pull out. Normal car drivers know this better than most cyclists although not all of them will let the bus out first as they do not want to be stuck behind it. As a cyclist you do not necessarily have the same need to overtake as the bus is likely to be faster than you between stops.

Hence, as a general rule, you should overtake the bus if the general situation is safe AND the bus does not have its right hand turn indicators on. If the bus does have the right hand turn indicators on and you overtake then that is against the spirit of the Highway Code.


I use a Cateye Strada Wireless on my mountain bike. It's taken quite a bit of abuse and hasn't let me down yet. My only complaint is that it's easy to reset your trip info by accidentally leaning on the computer for a few seconds. This can be seen as a benefit as well, as it's easy to reset your distance if you're navigating and need to know how far until your next turn even if you're wearing winter gloves. It's a basic computer, no cadence, GPS, HRM, or anything like that. That stuff just takes the fun out of riding anyway.

I'd recommend that you loctite the wheel magnet, they'll come loose over rough terrain.

They get good reviews at Amazon too.


Determining front & rear derailleur compatibility

Front and rear derailers are essentially independent -- so long as the two derailers can function with the same type chain they can work together.

Derailer "fit" basically involves 4 factors:

The amount of chain that can be "absorbed" by the arm (rear derailer only)
The index "pitch" of the derailer & its shift lever -- how far it moves in one step (indexed derailers only)
The total distance the derailer can move in and out (adjustable to a degree)
The angle that the derailer describes as it moves in and out

The amount of chain that the rear derailer arm can "absorb" between the most extended chain position and the most "relaxed" is generally specified as a number of teeth, being the difference between the sum of the teeth on the largest front and rear sprockets and the sum of the teeth on the smallest front and rear sprockets.

A sprocket cluster has a number of sprockets joined together with a certain "pitch" -- the distance between sprockets, as measured from (to pick one point) the outermost surface of one sprocket to the outermost surface of the next sprocket.  The "pitch" of the derailer/shift lever must match this sprocket cluster pitch or the derailer will never be able to be adjusted to shift between sprockets.

The total distance the derailer must be able to move is the index pitch times one less than the number of sprockets in the cluster.  Eg, for 5 sprocket cluster with a 5mm pitch the derailer must move 20mm from innermost to outermost.  Note that most derailers can be adjusted with the high and low limits to 2 or 3 different numbers of sprockets.

The angle is a little more complicated, and also not always well documented for different derailers.  The rear cluster on a mountain or touring bike generally has a wide range of sprocket sizes and hence the angle that the derailer movement must describe relative to the axle is fairly steep.  A racing cluster, on the other hand, would tend to have sprocket sizes very close together (only one tooth difference in the extreme case), and so the angle relative to the axle is fairly shallow.  Derailer specifications may state this quantity as a range of sprocket sizes, or a range of teeth (or may omit it entirely).

(Obviously, "angle" is also an issue for front derailers, and here the acceptable sprocket sizes should be clearly spelled out.  Your standard front derailer may not handle that super-small granny gear, for instance.)

Most 9-speed derailers can be adjusted to work with an 8-speed cluster, so long as the 8-speed cluster is using the 9-speed pitch.  Unfortunately, the pitch of 8-speed clusters is not cast in concrete, but in most cases it's the same as 9-speed.


2 questions: What bike is this? Also is this front wheel too big?

Really hard to tell from the pictures. One thing I am certain of is that almost none of it is stock. A few observations:

The main frame is lugged, has full length brake cable housing and horizontal dropouts and starred bottle braze-ons. All of those date it to sometime prior to the late 80s. Split brake cable housing on road bikes became the norm on production bikes in the late 80s. Horizontal dropouts also largely disappeared from mass production bikes due to the introduction of indexed shifting in the mid to late 80s.
The fork is a unicrown model. Unicrown forks on massed produced road bikes didn't really become the norm until the early 90s. This one has a threaded headset so it mostly likely predates the late 90s by which time threadless became the norm on mass production bikes in the interest of cost savings.
Sintesi is an Italian company who came on the scene in the early 90s and are still around though no longer in the US market (AFAIK). That said, "Sintesi" is also Italian for "synthesis" so it could simply be a model name rather than actual brand (for example, Irio Tommasini offers a model called the "Sintesi" but this isn't one of his)
The stem is likely from the 70s. CB was a common brand back then. The brake levers likely say Universal, Weinmann or CLB. The exposed brake cable date them to prior to the late 80s at which point "aero" levers had become the norm.


How to prevent wrist pain on road bikes?

I switched bikes a year ago, and I noticed on my rides (50km - 70km) at the time that I had some numbness / cramp / pain in my hands and wrists, it was so bad on some rides that I need two hands to change gear.  The bike had slightly different geometry than my previous road bike.  I now ride frequently 100km and even up to 180km with little or no pain.

Here's what I did and what changed:

1) I took the bike to my LBS and asked them if there was something they could do.  The adjusted the shifters outwards so that I wasn't stretching so far to change gear. A good bike fit may be the only solution you need.

2) Good gloves with good padding in the right place, to prevent putting too much pressure on the nerves that run through your palm.

3) rotating hand position, on a road bike you have 3 (or possibly more ) hand positions.  Use them.  They are not always practical in every situation but you can often switch from the drops to the hoods or vice versa on the flat, and the hood to the tops or vice versa on climbs.  This change in position will help with cramping.

4) finger clenches and stretches.  As soon as I start to feel my wrists or fingers getting tired I take one hand at a time off the handlebars (where it is safe to do so) and clench and stretch my fingers 5-10 times.

5) Hold the handle bars loosely.  My main problem was that I was gripping the handlebars way too tightly.  If you relax your grip to the loosest possible you will reduce cramp and reduce the effect of vibrations from small bumps and rough road surfaces.  This is especially important for long fast downhills.  I would grip on for dear life (doing about 60kmph - 75kmph) clearly you want a harder grip as even small bumps can be dangerous, but squeezing very hard on the handlebars will give you cramp in no time at all.  Also when braking on the down hills its better to pump the brakes rather that keep them on the whole time.

All this takes practice and I am sure that the muscles in my wrists got used to the abuse they were getting too.  In the end I am fine.


Where can I find replacement pads for a bicycle helmet?

Visit the friendly folks at your local bike shop at a quieter time of the week and ask. Chances are that they will have plenty of spare pads tucked behind the counter. Buy something else at the same time and they might let you have them for a favourable price.

This is one area where a local bike shop can provide the service that you do not get shopping online, where it is all too easy to get the wrong bits and pay postage for the privilege.


BB spindle length standard for single speed bike?

There is no 1 standard square tapered bottom bracket axle length for track frames.
The crankset dictates the bb axle length, it's not as varied as with crankset with gears, but there is more than one.
The range is much smaller than with gears, track bb axle lengths mostly go from 103mm - 112mm (there are smaller and longer for less common cranksets).
I think 103mm and 107mm are the most common sizes, given that their respective cranksets would be the most common cranksets. Although, this doesn't mean that there aren't plenty of others.
Examples:

Factory5 Pista Lattice Chainset - 103mm
Stronglight Track 2000 Chainset - 107mm
Sugino SG75 Bottom Bracket - 109mm
Campagnolo Record Pista Bottom Bracket  - 111mm

There are many more examples, but I verified these by using the Velodrome.shop website.


How to remove an older Shimano Hollowtech crank?

Every Shimano crank has its model number stamped on the inside of the arms.

If you have an Octalink BB, all you need is either an Octalink crank puller or an adapter.

Below is an adapter type tool. It fits in to to the end of the spindle so that any normal square taper type crank puller can be used. They work as well as anything and only cost a few dollars, or at least did when they were a more commonly seen item, so if you have a crank puller already they're a good choice. There are some different ones out there that are all basically the same thing, and I believe they can all do both Octalink and ISIS. (I have a non-Shimano one that can and I think the Shimano one pictured can too, but not 100% certain.)

Some crank pullers can do both Octalink/ISIS and normal square taper, like Park's one with interchangeable bits:

There are also Octalink/ISIS-only crank pullers. They're kind of the least desirable option if you're buying tools these days because these cranks are relatively uncommon, despite the years from about 2000-2004 where there was the perception they were going to be the new normal.


This appears to be an EZ-Fire type shifter.  Shimano or copy-cat. One model number is ST-EF29.  That spring is misaligned and you'll need to get that seated properly. Then I suggest a good dousing with WD-40 or equivalent and exercising the shifter repeatedly. You may need to use a toothpick or the like to scrape out old grease and dirt.  After cleaning, follow up with some sort of wet lube and work the shifters again. I've linked to a video showing some work being done on a very similar shifter to yours.
Typically I don't find these types of shifters "broken" but rather gummed up or pieces disconnected like your spring. It's common for the junction to the gear indicator to be disconnected and/ or the little plastic connection broken. This doesn't affect the actual shifting just the gear indicator.
You have a good chance of getting this working sans the "dodginess."


It shouldn't be too different to tapping out anything else, the added difficulty being that you would normally clamp the workpiece in a vice and you don't have that option.  I'd take the wheel off and lie the bike down on a bench with scrapwood in place of the axle (try to clamp/screw it in place) to give you something to push against other than the frame.

Is the frame alloy or steel?
Especially if it's steel you really need to make sure the pilot hole is exactly the right size first - which probably means buying a drill bit specially.
Getting a tap started in steel isn't all that easy especially as you can't get the frame in a vice, in alloy it's not too bad - so a brand new decent quality tap is a good idea for steel,as is just smoothing the edge of the pilot hole with a bigger drill or countersink tool before you start. If you're buying the tap, get a taper type - they start much easier than a second, and you've got plenty of room to come out the other side with the wheel off.  A decent tap wrench is worth the extra money over the junk that sometimes comes in cheap tap/die sets: you want the tap to be held securely.

Even if the pilot hole is already the right size for your tap, running a drill down it to take the paint off won't hurt.

Chain oil should do as a cutting fluid if you don't have anything better, then once you've got a thread started remember to back the tap off every now and then (e.g. forwards half to one turn, back a quarter).

Make sure to clean up all the swarf afterwards so it doesn't get anywhere important.

I assume the chain is catching on the nut rather than the bolt itself - you can buy half nuts / lock nuts which are thinner.  You'd need to threadlock it on.


Front hydraulic disk brake is too powerful on MTB — solutions?

It's hard to say exactly what the cause is, but I see two main possibilities:

Mechanical causes

Brake pads.   If the pads are very close to the rotor when at rest, and have minimal motion to close on the rotor then that may be enough to wedge them.  Try inspecting the brake pads and if worn, replace them.  Brake pads are consumable.  Thin brake pad material will reduce your "modulation" zone, same as hard brake pads on rims do.   Could consider swapping your pads front to rear caliper temporarily as a test.
Pistons. If your pistons are a little gunked up at the sides, they may not be retracting fully.  This may be limiting the distance that the pads have to travel to be hard on the wheel.
Rotor wear and damage.  Spin the front wheel off the ground and look closely at the rotor—it should not wobble or divert side-to-side, and the friction surface should not have burrs or obvious wear.
Fluids. I doubt these are the cause of your issue.  Low fluid, or air bubbles will exhibit as spongy-feeling levers and you don't have that.  (edit) though @t_bacon points out that if the system is over-filled it will be slightly pre-pressurised, which will be pushing the brake pistons out a little all the time.     It's definitely worth checking if the fluid is over-filled, by opening the bleed screw and see if fluid squirts out at all.

Technique

When braking, your lever should have a range of motion before the brakes are wedged hard-on.  How tight you squeeze your fingers controls the level of braking effect.   There's a great answer at What does "modulate" mean when referring to brakes? Just visualise your flatbar lever instead of road brake levers, the concept is identical.
Body position for fast braking should be "arms straight and arse back"   If you try and stand up on the pedals while hard braking your center of mass is higher and theres a moment-of-rotation which robs your rear wheel of traction and imparts a forward force on the rider.

One suggestion would be to swap bikes with a friend and try some carpark laps on another bike equipped with hydraulic brakes, and to get that other rider to try your bike brakes.  Decide if its a problem endemic to your bike vs technique, and go from there.


Are there any bus companies that take bikes and go between Washington DC and Philadelphia?

It turns out that Focus Transit actually goes between DC and Philly still.  The guy on the other end of the phone didn't know what he was talking about when I called.  They take bikes.


Truvativ Firex chainset replacement middle 32 tooth chainring & bolts

According to this bike shop it takes Shimano 4 bolt 104mm/74mm BCD chainrings, so you should be able to use the Shimano rings. If you have a spare bike and the right tools, take the cranks off, remove the ring and take both into a shop. That way you/they can check the fit before you buy a chainring. It's one of those times when you're better off paying a premium for LBS service so you don't end up buying multiple wrong parts online.

I don't know how (un)common those chainrings are, but we still get them as a new stock item in Australia and there seem to be lots of hits in google


What is a good replacement for a cable end cap?

Those end-caps are quite reusable. If you take a pair of pliers and squeeze it gently so that the flattened portion opens up you can then slide it back onto the cable. Using the pliers you can then re-crimp it on the cable. Although it looks ugly and everyone will know that you are too cheap to buy a 10c end-cap.

A little bit of superglue placed at the end of the cut seems to help keep the individual wires from separating.


How to install bicycle pedals without a notch on the spindle?

You have to use an allen/hex wrench, that's why they have the hex hole in the axle. Going from the opposite side through the frame is easiest.


Fixing a flat - how to find the piercing object?

The object that pierced the tire and tube may have been left behind or it might be embedded in the tire but hidden in the rubber. This can happen with small pieces of glass, wire, or thorns, especially in thicker treaded tires such as those found on a mountain bike. When the rubber of the tire is compressed against the ground the offending object will stick back out through the inside of the tire, re-puncturing the tube and then as that section of the tire loses contact with the ground the object conceals itself again. It's almost like a bee's stinger.

First thing I would do is just slap another tube in the tire. If you have another flat in the same place then you might have something still stuck in the tire that isn't immediately obvious. If you know how the tire was oriented against the tube, inspect both the inside and the outside of the tire around where you think the puncture occurred. Do it under bright light and look for small cuts in the tread. Use a pick or tweezers to dig around in any cuts you find to ensure that nothing is hiding in there. If you find something, great! Problem solved. If not it may be coincidence.

I'm also an advocate of patching the inside of tires after anything more than a pinhole puncture. If you have a cut that is more than a millimeter or two, you probably want to boot the tire. Otherwise you've got a weak spot where debris is more likely to penetrate the tire and pop another tube. You can buy tire boots, which are expensive, or you can use the glue type (not glueless) tube patches. I've had great success with tube patches on the inside of tires, even with road tires and mtb tubeless setups. Keep in mind that this wont work on cuts bigger than a few millimeters.


Can shimano di2 be programmed to be automatically readjust shifting for different hub/wheel types?

Quick answer:

You would need to use a PC, and you would need to make sure that the wheels had reasonably close original chain line positions for this to be possible. If not, then no, you can't do this.

Long answer:

Shimano's E-Tube software does allow you to save presets for adjustment and switch settings.  That means you could have multiple presets saved for the electronic portion of the shifting adjustment.

However, if the difference in required settings between the wheels is more than could be adjusted for by adjusting cable tension on a mechanical system, then you will still need to adjust the limit screws on the rear derailleur.

Since those are still a manual adjustment, there is no way to ensure that swapping between wheels on an electronic system is possible using only the preset system.

Also, there is no way at present to swap between presets on the fly with the road Di2 system, so you would need to plug the system into the E-Tube software on your PC.

There is the the possibility that this might change, since the new 2015 XTR Di2 system has the ability switch between shift maps using the SC-M9050 Display Unit. At present, though, shift maps only affect the order of shifting for XTR's Synchro shift system.  They do not allow shifting between preset shifting adjustments.

Since the Display Unit is functional with the road Di2 systems, it is possible that a firmware update could enable the ability to swap between presets.  Without the ability to make the manual adjustments the preset swapping would have limited utility for this purpose.


Can i stop my frame scratching my seatpost?

Possible solutions:
  - Let a bike mechanic ream the seat tube slightly
  - Wrap some sanding paper around a broomstick or similar an grind the sharp edges


What needs to be considered when building a winter bike?

Good for you, to think of riding as a year-round activity.

I would choose an older steel frame (Specialized Rockhopper from 1994?). Steel is very durable, and the older frame is less to be worried about with salt. Put a little FrameSaver on the insides, and don't worry about it. (I'm not an expert on these, just a Grant Petersen fanboy).

You really don't want to get stranded in an Ottawa winter. Add some storage, and carry:

a plentiful toolkit, including a multitool, pump, and spare tube.
cash for bus & phone
spare batteries for your light
compact warm items, like a balaclava, gloves, and a wool hat

The trick to rim brakes in the wet is to dry them out before you need them. When you anticipate a need to stop (approaching a driveway or intersection, for example), lightly apply the brakes. After one rotation of the wheels you'll have most of your braking power back. After a second rotation, they'll be in great shape.


There are chainguards that work with derailleur bikes. Your belt might be wider than a chain, but it isn't wider than a triple :-)
Something like http://www.sjscycles.co.uk/hebie-chainguard-for-triple-ring-systems-with-a-48t-outer-ring-prod19993/
(If you've got a 52t chainring, it might be trickier to find something that will fit.)


Raising handlebars using a stem raiser on B'twin Triban 500

As mentioned in comments a steerer tube extender should not be user with a carbon fiber composite steerer tube. Less expensive CFC forks often have an aluminum steerer tube.

You may want to consider a stem with a greater angle that will give more handle bar rise before a steerer tube extender, that would be a stronger option.

Are you riding with hands on the drops of the bars, or on the higher brake hoods position? Most riders spend most of their time on the hoods. If you are riding on the  drops and that feels too low, try riding on the hoods.


Am I too tall to bother modifying my old trek?

If you adjust a bike to the max and its still significantly too small, you should sell the bike and get a new bike.

There are extra long seatposts, and extra long quill stems and what not, but in all likelihood its not really worth it if the bike doesn't fit with the normal seatpost + stem; the other parts of geometry like top tube length are probably too small anyway.


It sounds like the issue that you're having is very similar to the one that time-triallists and triathletes have with disc wheels. Luckily they've come up with a solution for exactly that. What you're looking for is called a disc wheel valve adaptor, often referred to as a "crack pipe" for obvious reason due to its appearance. The most widely used and durable one is the silca version (https://silca.cc/products/disc-wheel-mini-chuck) because of the replaceable seals and tiny head which is easy to fit in the tiny space with the valve. There are plenty of options out there for less money as well such as this one by Fast Forward:
http://www.wigglestatic.com/product-media/5360051984/ffwd-valve-adapter.jpg?w=430&h=430&a=7


The correct answer is 'no', you cannot "easily install a quick release skewer" on this bike.

The easiest way would be to buy a different front wheel that is already built with a QR skewer and swap the whole wheel out (make sure to check for correct size and hub spacing before you purchase). Alternatively, you could buy just a new hub that uses a QR skewer, but to swap-out your hubs you'd essentially be re-building your wheel (spoke by spoke) which requires a lot of expertise and specialized tools.

As an alternative, you might consider finding some vintage winged-nuts. If you can find some that fit your current axles, they will serve the same/similar function as a quick-release skewer (that is, they'd allow you to quickly remove your front wheel without the use of a tool).


It sounds like you have a slow leak, either from the valve or from a tiny puncture in the tube, like Batman mentioned in the comments.

An easy way to fix this is by simply changing the tube in the front tire. If you've never done this before, this video may help or you can take your bike into your local bike shop and have someone fix it for you. If you choose the latter of the two, ask if they can teach you how to change out the tube, since this is an invaluable skill to have.


What is the difference b/w dropout diameter(9mm) and 3/8"(9.478mm) Tpi bicycle axles

I just checked two frames and forks drop outs. They all measured at least 9.5mm. They all allowed a 3/8" bolt to pass through. If you are having doubts about your particular frame, get a 3/8" bolt and see it fits. You also need to verify that the nuts will sit correctly in the front fork.The nut must sit flat on the fork not on top of the safety tabs (also called lawyer lips).


There are a couple products that already exist for doing what you describe.

Although i think you could also probably use a tube like you said, however if dirt did get in, the tube might keep it pressed against the stanchion which could result in scratches. The tube may also balloon when the fork was compressed due to the non-breathable nature of a tube.

The first that comes to mind of existing products is the Lizard Skins Fork Boot, they also make them for rear suspension as well which i have used. I have not used the Fork Boots but i have been happy with every other Lizard Skin product i have used. They are a breathable neoprene material but protect the stanchions. Image below

In addition, in my opinion the best defense is keeping it clean and well maintained. Wiping off the stanchions when they become dusty in addition to using a proper lubricant designed for stanchions to reduce friction can go a long way for fork life. One example is Wet Seal by Miles Wide, there are a lot like it though. Wet Seal was developed in part by Suspension Experts who in my opinion do awesome fork work so it is what i would recommend but there are others available as well.

This stuff also works pretty well for stanchions, just don't get it on your brakes!


How much value do groupsets gain/loose per year?

In my experience, it depends on how much has actually changed. Usually the lower quality groups (Shimana Alivio/Deore, SRAM X5/X7) don't change too much because they are very similar to the OEM parts. However, the more expensive groupsets incorporate the trickle down method you mention. Things like clutch derailleurs are becoming available in the middle price ranges versus the top tier. Adding something like that will greatly decrease the previous year's model, while increasing the new one's.

Most of the time though, it's like a car. As soon as you drive it off the lot, the value drops. Even if it's brand new, as soon as the next year rolls around it's lost value. Marketing and hype are what sell product and new product is always pushed first.


Looks a little tight. There should be +/- 0.5 inch vertical movement of the chain possible halfway between the sprockets.

Park tool has a great video on single speed chain replacement:

             (link starts the video at the tensioning segment.)

Readjust tension and see if it makes a difference. Also make sure the wheel is parallel to the frame.

1/8 in (3.2 mm) wide chains are typically used on bikes with a singlespeeds, but 3/32 in (2.4 mm) chains are used also. Compare the new and old chain width. If it's the same it's good. ('Width' here means the spacing between the inner plates.)

Did you replace the front and rear sprocket with the chain? Check the sprockets for wear, especially the rear one.


Tiagra upshifting jumping 3-4 gears in middle of cassette

That sounds like the shifter itself is malfunctioning.

If the cable or derailleur was hanging up you would get delayed multiple upshifts after clicking the lever several times, but you are saying that a single click results in a 3 sprocket upshift.

My guess is that the pawl mechanism in the shifter has worn and is slipping when upshifting, but is managing to hang on when downshifting. To confirm this you could try detaching the shift cable from the derailleur, putting tension on the cable manually (as close the shifter as possible if you have exposed shift cables, to eliminate cable or housing problems from the test) and seeing if you can get the shifter to slip when upshifting.

If the shifter is the problem, they are not serviceable. A replacement is necessary.


Can I use long reach calipers on my cyclocross bike?

I've just looked at the Centurion website and it's not clear from the pics or the German specs whether the frame and forks have caliper mounting holes. Look for a hole in the centre of the fork to take the caliper, and a corresponding one in the centre of the rear cross-brace above the wheel.

If those are there you can use caliper brakes of some kind, if you can get ones with the appropriate reach.

Bear in mind that you may also need to change the levers to pull a different amount of cable, or use some kind of adapter.


The problem is that the metal fender (or fender bracket) has some spring in it and wants to spring back placing constant tension on the plastic retaining bits that hold the slider. Ideally, the sliders should not be under any tension or compression - they just should keep the fender from some side to side and a little of fore and aft movement.

If you have a metal fender: I would bend the fender so that it's closer to the wheel even when under no tension:

Take off the sliders
Push the rear of the fender against the wheel with enough pressure that you feel the metal bending
Release and repeat until the fender springs back to about the position you want it to stay in.
If it keeps springing back even though you've pushed it against the wheel, you might need to take the wheel off to get some additional space to push
Once the fender is about where you want it, then (put the wheel back on and) the sliders back on

Plastic fenders: If the fender is made of plastic or wood, then there is a metal  L-bracket underneath the brake calipers bolt that holds the fender on. This bracket needs to be bent just a tad so that the fender is at a better angle viz a viz the wheel. It's easier to bend this with the fender removed as you can crack a plastic or wood  fender.

Finishing Touches: After you've done all that, you can put some polyurethane or hot glue on the sliders to help them grip a bit more. I like to use glues that I can easily take off again. One brand I like is ShoeGoo. It is incredibly tough and tacky but you can also get it off hard plastics and metals if you need to readjust the fenders again.


Where to find a good bicycle-trailer lighting system...in Canada

I buy all my bike lights from http://www.dealextreme.com - they are in HongKong but have free postage to Canada.

You are just buying the same made in China stuff in the shops direct from the makers in China.  Avoid the very cheapest stuff (destined for a Dollar store near you!) and check the reviews.

edit: specifically for your trailer you can't beat this superflash from mec

edit2: Lights switching off is normally a problem with the batteries not the switch. The flashing LED lights are microprocessor controlled and a fraction of second interuption in power resets the CPU. Check the batteries are a good contact, especially rechargeables which are a tiny bit shorter than Alkalines. You might have to bend the battery clips to make a good contact.


There are good Campagnolo parts on it which may be collectible, and it is a Masi frame, which held quite a bit of value for some time. It's not in bad shape, but not so good as to justify mint condition collector value.

I doubt it has any serious value even fully restored unless it was actually ridden by Fausto Coppi or Eddy Merckx (which is understandably unlikely), but if you take the time for a restoration, you may get a couple thousand or so dollars from a collector with a particular interest in Masi.

Anything beyond that would require a specialist in the subject, and provenance on the frame.


What do I need to research to switch to an internally geared hub?

The first thing you should be looking into is gearing to ensure that an internally geared hub will work for you! The more you pay, the more gear range you get out of a hub, but even the nicest internally geared hubs don't match the spread of standard mountain bike gearing.
If you've decided that an Alfine 11 hub is for you then to answer your questions in order:
-the axle size shouldn't be an issue.
-the hub spacing is 135mm. That's mountain bike spacing typically. Apparently it can be adapted down to 130mm but I'm not going to detail how to do that here
-sell it/keep it/ use it as a paperweight
-The hub will have a dedicated shifter. I seem to remember that there are both trigger and grip shift options. Should fit without issue, though you'll probably have to take your grips/bar tape off.
-Yes, unless you have an incredibly nice rim with the proper drilling that you want to re-use.
You will also need a chain tensioner if your bike does not have horizontal/track-style dropouts, which I doubt it does. I believe there's one that goes along with the Alfine that Shimano sells as an accessory, though I don't think you have to have that particular one.


It will damage the frame long term, or rather shorten the life expectancy for the rear triangle. Short term… it depends how short the term is.
Wheels are typically have standardized widths, as are frame's inner distances between the dropouts made to match them. Unless the frame is already damaged and bent or has a manufacturing defect, as the comments above suggest, you are likely trying to squeeze a 130 mm road hub wheel into a 135 mm MTB-frame (or maybe a 135 mm MTB wheel into 147 mm Boost-QR? does not matter, really)
Note that you may also have problems with adjusting the rear derailleur, as the cassette will also be off its intended position. It may not be possible to shift into the biggest rear cog.
If I were stranded somewhere far from proper components with only a 130 mm wheel to have, I would rather have attempted to add some sort of spacers taking up 2.5 + 2.5 mm at either side of the wheel, rather than compressing and stressing the dropouts.


How can I stop air leaks unscrewing a tire from compressor?

These compressors are intended for cars, and because of the much higher volume of air in those tires, they won't lose enough air to matter when unscrewing them.  As noted by another poster, you can get a replacement head with a Schrader valve.  Some of these compressors have a crimped-on end fitting, so to replace them you would also have to get a suitable crimp and crimping tool, although a barb-type with a hose clamp will also work.  These compressors can work well for bikes, as most won't compress above around 125 psi, which, while much higher than is appropriate for many tires, is not likely to blow the tire off the rim if you get distracted while inflating.  However, some go as high as 200 psi, so you will have to pay attention.  I would agree with another poster, though, and get a good floor pump and throw it in the car.  I think the Silca Super Pista is the best out there for bicycles.  They are not inexpensive, but will last a lot longer than the car inflators, and they provide a bit of upper body exercise in the process.


How can I inflate a tire to the correct pressure?

One term: Mechanical advantage.

You need a pump with the correct mechanical advantage. In the case of an air pump, the size of the piston defines how fast it does its job and how high a pressure you can put into a tire.

Let's say your pump has an effective piston area of 1 square inch (6.5 cm²). That would mean that in order to pump 100 psi (pounds per square inch; 690 kPa = 690 N/m²) you would need to exert 100 pounds of force (or in SI units, 690 kPa * 6.5 cm² = 450 N) onto the pump.

A pump with a smaller piston area will give you an advantage, requiring you to push less hard in order to achieve the same pressure inside the tire, but it also will be slower, as every piston stroke will push in a smaller air volume.

That's why there are some pumps better for low pressure, high volume (like fat MTB tires) and other are better for high pressure, low volume (like skinny road tires).

There are also some pumps with dual mode. They have a mechanism to switch from high volume/low pressure to low volume/high pressure.

The other parameter of a piston is its travel (length of the stroke). A pump with small piston can be "faster" if it has longer stroke, as each stroke will push in more air.

A 700x38c tire is usually wide enough that can be used at lower pressures (I use a set of those and keep them between 40-60 psi (280-410 kPa). Remember most tires have a marking stating the maximum pressure, not necessarily meaning that you must use that pressure. You have to consider your weight, the desired comfort, and the quality of the roads you use.

If you have been setting your tire pressure by hand, and have got good riding performance/ride quality/comfort, and have not had pinch flats (snake bites), then most surely, that pressure is the right one for you on that bike.

If you seriously need to be able to pump your tire higher, consider investing in a pump better suited for higher pressures.

A track pump is the best option to have at home or carry in the car, as it is big and allows you to apply all of your weight to it, they are more comfortable to use and may have an integrated pressure dial. A hand pump is more oriented to be an emergency device to get you out of trouble in case of a flat.

Just in case: Have you calibrated the gauge? If not, compare it with another measuring device. Take several readings to check whether it is giving you the correct reading.


What is the maximum input torque on Sturmey-Archer internally geared hubs?

A pro cyclist putting out 1.4 kWatt at 60rpm at the starting sprint has a torque of almost 2000 lb-in or 222 N-m.

A recreational bicyclist may be normally only be capable of just 1/10th that but even an out of shape Clydesdale (heavy but strong rider) just getting off to a start on a hill may momentarily hit that level. If they weighed 200kg but jumped on the pedal and momentarily put 800 newtons of force on a 170mm crank, that’s 136 n-m, or still a lot of torque.

If I was an engineer, I’d want to make sure that my components could handle that level peak on an occasional basis. If you’re really worried, get a Rohloff as they’re really well designed.


Is shimano ct-s500 chain tensioner supposed to move around its bolt?

Yes, no problem. When there's no chain in place it's normal for rear derailers and this type of chain tensioner to be able to rotate like that.


Spokes bent like that can't take any load (tension), so it would not work. However, bending multiple spokes around each other can produce a feasible wheel with non-straight spokes, like the last photo here. Note that in this particular wheel a single broken spoke will cause multiple others to lose tension, most probably rendering the wheel unrideable.


What kind of bike rack can go with this bike?

Your bike looks like it comes equipped with a full-suspension frame, and the suspension mechanism is located where one would usually attach the rack stays. This will make attaching a rear rack extremely difficult, and almost certainly less secure.

I don't recommend attaching a rear rack to this bike, particularly not one that will be holding a child seat.

Instead, you could look into a child trailer. (For more information on child seats compared to child trailers, have a look at this answer.) Please note that pulling a trailer with any full-suspension bike can cause problems (see the comments).


It does look like the cable has missed the channel it should come up through the mechanism vertically, i.e. it is at the yellow arrow but should be at the blue arrow aperture (if I'm identifying the cable correctly):

Little differences like that often mean that the force is incorrect, or that the cable is restraining the movement of the derailleur.  If it's otherwise correctly routed, you might get enough slack another way, to guide it into the open aperture i.e. by moving the derailleur out by hand. Superglue is quite effective at tidying up a frayed cable if you need to re-route it. Twist it so neat and then dab in superglue. Not too much glue tho or it's too bulky.
Double check the support screw is doing work against the plate as well.
Shimano tech doc extract:

If you haven't made use of the Shimano Dealers' Manual then give it a study. Set up on this style is quite different to traditional designs. There is even a mark to show when cable tension is correct and advice on which trim position to use for setting the high limit.
There is a kind of in-buit barrel adjuster, that outward facing Allen bolt on the top assembly. I think you would loosen it off when the cable is undone and once cable is in again, tighten the bolt to add tension.


There are sizing cranks that are primarily used by fitters. They're expensive and heavy and usually intended for a fit machine more than going on an existing bike. Ones I'm familiar with are square taper so getting them on to modern bikes would involve jumping through some hoops, but there may be a 24mm one out there.
Trying all the lengths in a short amount of time and with minimal contrivance would be a good thing to find a fitter's help with. Crank length and saddle fore-aft are numbers that play off each other, so you want to get your fore-aft dialed at the same time if you can.


Replacing Crankset. Do I need to replace chain? Then do I need to replace cassette?

If you replace the crankset you almost certainly get new front sprockets.  Compared to the cost of the crankset and sprockets a new chain is chicken feed, so get a new chain.

Whether you need to replace the rear cassette is a whole 'nother question, pretty much independent from the front.  If the cassette is badly worn it may cause your chain to wear slightly faster, but not enough to worry about.  And you may find that the rear shifts poorly with the new chain, or suffers some "chain suck", but probably it will be OK, if it is now.


Replace hub from old cassette to new fixed

I've seen this done and mostly work out ok, but I still wouldn't recommend it for the commented reasons.  If do want to attempt to reuse the spokes, you'll need to buy a hub with as close to the same flange size as possible.  If you go with a wider flange, you'll end up with spokes poking through your rim that you'll need to cut and possibly rethread.  If you go with a smaller flanged hub, the spokes may not be long enough.

Spokes are the answer to a question involving the effective rim diameter, flange width, pattern and a few other variables.  If you change any of those variables, the answer will be different and you'll need different spokes.


It's entirely plausible that you are experiencing muscle pain and fatigue on a bike with a substantially different and more aggressive riding position.

If riding on the drops is very unfamiliar and difficult, try riding on the hoods most of the time and switching to the tops to get a different hand position occasionally. (A lot of riders spend most of their time on the hoods rather than the drops.)


Can’t seem to put the wheels back on the frame

That's not the correct skewer for the wheel. I think you likely are using the rear skewer in the font wheel. Front hubs are typically 100mm between the drop-outs, rear are 130 or 135mm (or even 145mm on some mountain bikes that have stronger through-axle designs).


Probably ISIS splined. That’s the only one with splines of that length with the smooth end.
https://www.sheldonbrown.com/bbsize.html


Which tires (and rear fender?) for Bianchi Metropoli Uno hybrid bike

Fenders/Mudguards are more important on a commuter bike than any other style of bike.  That's because it helps keep you clean for wherever you're commuting to.

So the features you're looking for in a mudguard / fender are

Length - a rear mudguard should stop water and muck flinging off the back tyre from hitting you or your bags.  To do that, the rear mudguard should be long enough to finish at-or-below the level of your rear axle.  The front guard can be even longer because its job is also to protect the bike's BB area from road muck.  Its not uncommon to see front guards dropping even lower.Some have a leather or rubber "curtain" or mudflap that continues down where the guard stops, increasing its effective length.  Also, the front of the rear mudguard should ideally finish below your BB.  The longer front stops road-water from hitting you in the face while turning.

Example of an overall excellent design for mudguards. The silver L brackets at the top go into the stackup of your rim brakes, either on the nut or on the brake side.  So they will require a bike frame with a brake bridge.   Also see the two stays in a triangle.  They help support the guard.  Some designs simply flap in the breeze, which lets them rub the tires but does look slightly more sporty. The guard is also a great place to add reflectors, sticker-reflectors, or lightweight lights.

Good front guard example (note its not well-fitted to this bike, because the stays are curved, and there's an inconsistent gap between tyre and guard, and its mounted so the front edge is too high... it should bend down more on the leading edge.)

Clamping system - you need to inspect your dropouts and look for a spare hole for mounting the stays. Examples:
 The two yellow holes to the left are for stays.  Some bikes might have one, two, or even three holes.  Some have none.

For your bike, I can't see any but they may be hidden by the trailer mount.

If you don't have holes for mounting, you'll need either P Clips which look like this:
Or you may need to limit your mudguards to those which attach to the stays.  Downside of these is there's a lot more unsupported length so they flap a bit, and don't last as long.

Notice this one is too short in the front, and should have a second piece that goes from the brake bridge down to the bottom bracket.

Width - a wider tyre needs wider guards.  You should have guards that go further sideways than your tyre so they can catch water flung.
Material and colour - its completely up to you.  Steel, Aluminium, and plastic are the two common materials for guards, and you can get combinations like "chromoplast" which is a chromed plastic, being lightweight.  Some people have made wooden guards, but they tend to have one curve whereas a good guard is curved in two directions to follow the tyre.
As for Colour, whatever suits your bike.  Black, bright chrome, and matt chrome are common, but you can paint them any colour you want.  Matching or contrasting your frame to suit your taste.

Less-good mudguards there are times where compromise is required.  You should avoid "ass savers" because while they're better than nothing, they're not anywhere near as good as a full guard.

There are some designs that attach to your saddle - I have one and road water still drenches the back of my thighs.

Motor-cross style - these are intended to stop mud from packing up between the tyre and the fork bridge on a MTB.   Instead they help ease mud through the gap to be thrown off.  No practical use on your commuter.

Further information and reading here:   Very basic mudguard question and https://www.sheldonbrown.com/fenders.html


No saddles exist which are unsafe for mens' health. What exists are saddles which do not fit particular bodies and, most importantly, misconfigured saddles and bad riding postures which can give a man some health issues.


Is it possible to install a gas engine kit on the bike's existing speeds?

Generally speaking, no.
A liquid-fuel engine wants to turn a lot faster than a cyclist would turn the cranks.  That's why a retrofit engine often has a small drive cog and an enormous cog on the rear wheel, to decrease the revs and increase the effective torque.
The optimal speed of a small capacity liquid engine is somewhere between 1000 and 2500 RPM.   A cyclist would do 60-90 RPM on the crank, with 120 being possible-but-abnormally high.
If you want a motor bike, its often cheaper to buy a 50cc motor bike and leave your normal bicycle unmolested for riding.
Also, if you remove the ability to pedal, then your ride becomes a motorbike no matter what displacement limits you're under.

Additionally - these liquid engines cannot generate enough torque to pull away from stopped.  So the rider has to pedal up to a minimim of 10-20 km/h and then can release the clutch.  Trying to start a small displacement motorbike from stopped is impossible without stalling.
You need the pedals working to get them moving.


26 inch wheels and fork on a 27.5+ frame

Overall its probably cheaper and certainly easier to sell the bike you have and buy the one you want. Building a bike from a 27.5 frame with 26 components you may end up with a bike geometry that is 'out' and handles worse than you already have.

The new frame is likely a though axle, and may have a wider (Boost) spacing, meaning the rear hub will need adapters or replacing. The bottom bracket and seat post are unlikely to be compatible. You may need a new chain as the chain stay length could be longer.


The advice I have seen for a stuck piston is  a) hot soapy water, followed by Isopropyl Alcohol, followed by a small amount of brake fluid (Use the same that is in you brakes - mineral in your case) to lubricate the piston. If you google for "Stuck Bicycle Disc Brake piston" there is quite a lot of useful advise

Warm soapy water on it's own cannot hurt. Although I have never needed to do this, I would use a syringe to direct the water at the pistons to waste away as much crud as possible. Move pistons out (being extremely careful not to drive them out too far - put a pair of old pads in before squeezing the lever... When pushing them back in, do it gently) Watch for a piston moving more than the other. If one is not moving, hold the other in to get it free.  Then squirt water over them and wipe them off with a clean rag.

If the crud contains too much in the way of oils, the water may not be enough  - resort to the IsoP.

Wipe a clean rag soaked in a small amount of brake fluid over the pistons. If desperate, a normal mineral oil, but what every you do, don't use too much. You need just enough to put a thin layer over the piston, and more and you risk getting it on the pads (very bad for them).

Finally, and most importantly, get a clean dry rag and wipe the whole assembly down as clean and shiny as you can. Install pads and see how you got on.


What is the best way to improve my cycling distance over mountainous terrain?

You and I are in a similar place.  I can do 150 km flat rides with no problem, but 1000 metres of elevation increase wears me out.

So the longterm solution is to practice by doing more.  I've set a climbing goal in strava of 50 km vertical for the calendar year 2017.  As of Jan 15 I have done 3,435 metres, which is well on track, but its summer here.

Technique helps - learning to gain momentum from any downhill or flat bit and then carry that momentum as far up the next slope as possible.  Don't coast down grades.

Pacing is a big thing too - working your body to a point that is not your maximum, so you can maintain a speed up the whole climb.  No point going mad for the first quarter and then needing a rest stop.

Equipment - climbing is hard work.  I have an unfashionable road bike with a triple front, and a low gear that's below 1:1   (ie 26 teeth on the front and 28 on the rear cassette largest cog)   Roadies look down on triples, but this is about YOUR performance, not theirs.   Many MTBs had triple chainrings too, but 1x have become more popular lately.

In short, you might benefit from adding bigger gears, so that you can increase your cadence while climbing.  Mashing is not as efficient as spinning up a steep grade.  This might mean changing your cassette for a larger one, or having a choice of rear wheels available.

Weight - If you're lugging 2 bottles of water up, do you need them?  Its hard to justify carrying stuff that you might need, but some things like pumps are non negotiable.  Are you carrying too much food?

On the same vein - your bike's weight.  I changed from a 20 KG steel MTB to a 12 KG aluminium road bike and my segment times all dropped by 10% immediately.

This image shows how much of your energy goes into different things as the slope increases.  This one is aimed at MTB riders, road is worse.

Timing - riding in the heat takes energy out of you.  Consider riding when its cooler, like earlier morning rather than noon or afternoon.  Also, looking at the local weather forecast for a nice tailwind could help your climb.

Training - Doing specific training to target climbing, like hill intervals where you go hard-out up a grade for 30 seconds and then 2 minutes of relaxed climbing.  Repeat 6-10 times.

Motivation - go out riding with someone who is better than you.   Track your progress on climb segments in Strava, to see your progress. Here's an 800 metre segment at the top of a climb, where I got a PR today.  You can clearly see a decrease in my times over the last 20 months.  A bit more work and I might get to half the initial time, which would be awesome!

Other than that - practice.   You can't improve without doing.


Selecting a compatible BB: spindle offset

With Shimano there are "E" and "K" variations of bottom brackets that refer to coaxial mounted front derailleurs and chain guards respectively. The BB variations provide for enough space on the drive side spindle to build in another "ring" of the derailleur or the chainguard carrier.

For exact paramenters Sheldon Brown could be helpful too.
http://sheldonbrown.com/bbdrop.html


Sun protective clothing interfering with bike mirror

This is complicated.  The farther from the eye a mirror is, the larger it must be to provide an adequate field of view.  This is one of the (several) reasons that bar-mounted mirrors are often unsatisfactory.

Assuming you stick with helmet-mounted, you do want to get the largest mirror you can find, and one with a relatively long arm, so you can get it as far out to the left as possible.  But I find that even without any helmet covering, this doesn't quite allow me to see around the helmet.

What I do is aim the mirror so that, when I'm looking straight ahead, the mirror gives me a view of the left shoulder of the road.  Then, when I want to observe traffic behind me, I turn my head slightly to the left.  This give me a view behind, and the turning of the head adds sufficient leftward extension to the mirror to allow me to clearly see past the helmet.


How does the Pog Security Washer work when using it with the Pinhead wheel locks?

As I was writing the question I realized how they work, so I'll do this Q&A style. The Gator Grip Socket works by forming to the Pinhead lock no matter the lock positions. However, it's larger then the key, so when you put it on, if there's something else blocking the way that doesn't turn (like the pog security washer), then it won't work.

So technically if they created a new tool that was like the Gator Grip Socket but smaller, you might be able to still unlock the Pinhead locks with it. But even that would be unlikely because of the way the pog security washer juts out that would block you from getting a secure seal on it.


Identifying features of a mountain bike specific to a tall and heavy rider?

I would be looking at bikes with frames made of steel. A cro-moly frame will be most likely to meet the requirements you are looking for on your budget, and there are a lot of bikes with cro-moly frames available in different price ranges. Companies like Trek and Diamond Back make high quality bikes in every price range, you would just have to look at how each bike specs out for weight limits. Dont rule out alloy bikes, I just think they tend to fatigue faster under rigorous use. There is a company called Zize Bikes that might interest you, although they look pricey.


How do you evaluate and choose chain lubricants?

I've talked to a lot of folks about chain lube.  I've met quite a few people with strong opinions, and they vary wildly.  Some folks swear by paraffin wax based lubricants like the White Lightning line of lubricants.  Other folks swear by oil-based lubricants like Phil's Tenacious Oil.  Still others won't ride without a teflon based lubricant like Tri-Flow.  Everyone who swears by one of these three types of lubricants will tell you the others are terrible and will destroy your chain or some other nonsense.  The rhetoric is silly -- each of them works well enough.  I've had good and bad luck with different products in each category.

When it comes down to it, you just need to find a lubricant you like and use it.  The biggest deal, according to some very experienced mechanics I've talked to, is to keep your chain clean.  Your chain needs lubricant on it, but it doesn't take much to keep it lubed.   The big thing that destroys chains is dirt.  If you clean your chain frequently, it will last a lot longer.  When you clean it, you should be able to run your finger along the links (the top or bottom, not the sides) and have your finger come away with a little bit of lubricant on it.  If there's nothing there, you should lube your chain.  If you do this, what lube you choose won't matter nearly as much.

That said, there are some differences to take into account.  The two things I think most about are waterproofness, wetness, and application instructions.

Waterproofness: If you ride your bike in the rain, you need a lube that will resist washing off.  A lot of the inexpensive lubricants you can buy are not very waterproof, so by the end of your ride the whole thing has washed off.  That's bad for your chain.  If you look at the lubricants you're considering, the bottle should explicitly say if it's waterproof.  For this condition, Phil's Tenacious Oils work pretty well, as does Boshield's T-9 lube.
Wetness: Some lubricants leave the chain with a glistening wet surface.  When you put it on, you should be able to wipe this off a lot, but some lubes (like oils, and some of the teflon-based lubes) will leave an oily sheen whenever they are present.  This oily sheen can pick up dust from the environment.  If you're riding in a dusty environment you want something that will dry completely and still work.  For dry conditions, Tri-Flow makes a product that dries completely and leaves a teflon lubricating layer.  Boshield's T-9 is good here too -- it dries and leaves a parafin wax lubricating layer.
Application Instructions: Different lubricants require different rituals to apply them.  Some of them suggest you put them on the chain, wait 30 min, and wipe off the extra.  Others suggest you lube the chain and immediately wipe off the extra.  Some even suggest putting it on the chain, wiping off the extra, and then letting the bike sit in a warm space for 12 hours before use.  Depending on what you're doing, this may be impossible.  My girlfriend and I accidentally bought a bottle of the "sit in a protected place for 12 hours" stuff on a bike tour, and it was terrible.  We were camping, we had no protected place for it to sit.  When you apply the stuff "wrong", it works very poorly; we were applying it every 2 hours of riding, and still getting some nasty wear and squeaking.

So there you go: there's no one answer.  If there were, you wouldn't see so many products on the market.  If you give it some thought, and do some experimentation with a couple of the products that suit your needs best, you should settle on something you can use well, and go through slowly.  Chain lube doesn't need to be a big expense.


Solar charger for iPhone whilst on a bike tour - is it worth it?

I have actually used both 2 different sized solar panels and a lithium backup battery on Ragbrai. Whether any of these will work for you depends on:

How many days long is your ride?
How sunny will it be and how much time will you have to do a solar charge?
How many devices you need to charge.

For solar charging. The first lesson is you can not charge your device with a solar panel while you are riding. Solar panels need to be pointed directly at the sun to provide any kind of real power. The little solar chargers you see advertised are utterly useless. They might charge a phone if they were pointed directly at the sun for an entire day (15 hours). The larger solar charger I have is 14" x 12" with an adjustable mount so you can keep it aimed at the sun. I could recharge my phone (when off) in 4 - 5 hours.

Small charger (useless)

10 watt panel (works)

What worked the best was a large backup battery. They are not physically large- just large capacity. (15,000mAh or more). I used this for an entire Ragbrai. It charged my phone once a day for 9 days with power to spare. Note you turn your phone off at night, plug it into the charger, and the charger automatically turns off when the phone is charged. The phone saves power by being off all night. Wake up, turn the phone on and it's good for the entire day and evening.

Sample 15,000mAh battery

You can fly with these batteries in your luggage and probably in your carry on luggage. But the TSA often makes up its own rules on the fly and might decide to confiscate one in your carry on. I would keep it in checked bags.

TSA rules

Note that it takes about 2 full days to charge one of these batteries. You should probably test charging all your devices at home to see whether you can make it on your trip. You also need to remember that your battery is just as dangerous as an equivalent sized container of gasoline. You do not want to puncture it or expose it to high heat.

If all that information is confusing, I only take my backup battery on Ragbrai now.


What should I look for when purchasing a helmet?

In the US you need to look for one of three certifications:

CPSC sticker for the US Consumer Product Safety Commission standard
American Society for Testing and Materials (ASTM) has a F1447 standard that is is identical and may be more common internationally
Snell B-95 used to be more common, but as a higher, more rigorous standard I don't think you see it any more.

It's likely that helmets available online and for the UK market will carry one of the US certifications as well as a similar EU certification.  I know there is a "CE" certification but I don't know about what it entails.

Any helmet meeting one of those certifications will provide the basic level of protection you are looking for, even if it is just $15-$20 US.  Beyond that comes the world of look, style and performance. As helmets increase in price, they decrease in weight, increase in vents, and sometimes increase in adjustability.

I know you mention that you want to buy online, but you may want to purchase your first one at your local shop for the following reasons.

Different manufactures/brands fit different shapes and sizes of heads better.  For instance, I like Specialized helmets because they tend to fit my head shape and size better than either Bell or Giro.
The shop technician can help you adjust the padding and retention straps for a correct fit.  It's not hard, but it is critical for the helmet to provide the desired protection. I see people every day riding with poor fitting or maladjusted helmets.
It's always a good idea to build a relationship with your Local Bike Shop (LBS). You never know when you are going to need a quick or emergency repair, and your LBS is more likely to help out a regular customer.

After the first helmet you will have a better idea of what you like and what fits, and you can shop around online.  You will want to replace your helmet every couple of years anyway, as it loses structural integrity overtime.

The Bicycle Helmet Safety Institute is my favorite online source for helmet info.  Start with the How To Buy page, but be sure to surf around on the site.


It is important to understand that spokes work in tension rather than compression. What that means is that the spokes at the bottom of the wheel are not 'doing anything'. The load is shared by all of the spokes to varying degrees and, particularly with cross-laced spoking patterns, that load gets dynamically transferred to use the strength of the available spokes. You can actually knock out a chord of a dozen spokes on the cheapest of steel rimmed wheels and the wheel will still be able to support your weight and get you home, albeit with gingerly riding style with no kerbs or potholes attempted...

Therefore, even quite seriously mangled wheels that are as true as a poppadom are surprisingly strong when riding on paved roads in a straight line. As other contributors have noted the problem comes with the brakes and stability at speed. You really do want to make sure your brakes are not hitting the tyre or falling off the bottom of the rim. If you have the slightest doubt then you can ride the bike using the other brake as your primary, using the brake on the affected wheel for 'emergencies only'. This should not be a problem if the weather is dry and you know what you are doing.

Straightening out the wheel need not be something that you need to get the bike shop to do. Consider doing it yourself, with a spoke key on the wheel in situ. Here is a handy page on how to do just that:

http://www.kenkifer.com/bikepages/skills/spokes.htm

As for getting a spoke key, go into the bike shop with the bike and ask. There are a couple of common sizes and you will need to get the correct key for your bike.


Are there statistics on cycling trip distances?

Here's an article focusing on some of the most active cycling cities around the world, and this is reporting averages, not maxima. The source data they link to at Strava isn't available to me (redirects to the Strava login page, and I don't have a Strava login).

The data is probably biased towards more serious cyclists--I'd be surprised if the average commuter in Amsterdam is bothering to log in to Strava every time they go out.


Why are barrel adjusters different for brakes and gears?

The top one is to be threadded into a brake lever where the first flexible housing starts. This one is for a smaller hole size.  There are similar ones which have chunkier threads too, and they're not interchangeable.  Smaller ones again are found on older style caliper brakes right on the arm of the brake body.

Your second photo is for the downtube stops - where the first piece of flex housing ends.  It has serrated edges to hold against vibration, and a small spring to stop the round grip from rattling.  You may also find these directly on the rear derailleur, and very rarely on a front derailleur.

So short answer, they're for different locations on the bike, for different wire-driven systems.

Brakes have to cope with higher forces than gears.  This is why the brake inner is thicker than the gear inner cable.  So an adjuster for brakes has to resist those braking forces and has a lock or jam nut to hold position once set.

Brakes also sweep a range from relaxed to taut so it has a lot more "analogue" usage.

The gears need to position on one of 5~13 positions accurately, so by comparison its a more indexed or "digital" position.   Friction gears didn't use adjusters like these because the adjustment is in the rider's fingers.

As such, the gear adjuster needs to be more "dialable" and there are even people who will adjust their gears while riding, so on the downtube is more accessible than the rear mech.


This is a Cannondale frame, and i believe its from the model year 1990. The serial number reveals it was made July, 1990. Your bike does contain an aspect of the 1991 models which I'll discuss in a sec.

From 1986 to 1992, Cannondale used two versions of serial numbers, one of which was located on the bottom of the left chainstay as we see in your pics.  Your serial number version breaks down like this: First digit=rear dropout width.  0 correlates to a dropout width of 130mm.  Is this correct? The next two digits reveal the frame size. 20 inches in your case.  The subsequent four digits (here, "0790") are the month and year of manufacture.  The final four digits are the production sequence number, which i take to mean this is the 2204th bike of this model* made.  *It may refer to a sequence differing in detail than what i assert here (for instance, 2204th 3.0 Aluminum frame, size 20 inches, etc).  Reference: Vintage Cannondale.

It appears to me based on perusing the 1990 and 1991 Cannondale catalogs, that you may be riding a 1990 SM2000 Mountain bike from Cannondale.  Original paint scheme was  metallic blue rear 2/3's fading to silver in the front.  The decals were pink. This was the last year for the crimped chainstays, going to oval model year'91.

Your crankset appears to be a flavor of Deore and the '90 M2000 sported Deore XT crankset 48-38-28.  Looks like yours may have a 46T or 44T large ring, and several of 1991's models used Deore LX 46-36-24 cranksets. Other anomalies to my proposed model include your bike having an after market suspension fork; most models this year came with center-pull cantilever brakes, where yours are linear pull; the top tube of most 1990 mountain bikes sported 3 cable stops along the top. Yours appears to have only two. Is there evidence of a missing middle cable stop on yours?  At any rate, I do not believe any of these differences are fatal to my speculation. Even the lack of a third cable stop can perhaps be explained by production changes related to going into the next model year, 1991, where only two cable stops were on the top tube.  Being produced in July 1990, your bike was created at the beginning of the '91 fiscal year and it would be typical to start producing 1991 models the summer of 1990.  (I base this on my experience in manufacturing at Winnebago Industries--motor homes and John Deere--farm equipment). You have aspects of a '90 SM2000 (XT components, crimped chainstays) and 1991's model (namely, 2-cable-stop top tube).

Note that I do not believe your frame is the SM800 (the venerable "Beast of the East") based on your top-tube being level and not angled as the SM800.   The components are wrong for the SM700 and SM1000, however its possible your frame is these.  Measurements would help the case, and these figures can be found in the catalog.  "Mountain Frame Geometry" 1991 on page 15 and 1990 on page 31.  Here's the link to them via Vintage Cannondale

You have an excellent ride. Enjoy


Should I seal the open spoke holes on my front rim?

It would be best if you could get 16 hole rim (yeah I know the may be hard to find). Holes on the rim go in the zig-zag pattern, and since you skip every second, all your spokes are on one (zig) side of the wheel. This is less than ideal, and in my humble opinion bigger concern than rain coming in empty holes.


Please check which one refers to internal diameter and which one to the outer.
If the seat tube (the one on the bike) has an inner diameter of 27.2 and the seat-post has an outer diameter of 27.2, obviously they will match.
You can expect tolerances (variances, as more correctly mentioned by @weiwen-ng ) on the order of +-0.2mm, unfortunately.
Don't forget grease, especially when installing aluminium seat-post in a steel seat tube.


Conversion to horizontal dropouts (for fixed gear), V-brake

V-brake calipers have a radial (with respect to the wheel) adjustment range, so they can accommodate the wheel axle moving fore or aft a little.
What you need to do is make sure that the placement of the new dropouts does not place the wheel axle such that the brake track on the rim is outside the range of caliper adjustment.
You could do this with a simple cardboard template that marks the axle to brake track distance.


Switching from 3x8 to 1x11 would be an expensive upgrade, well beyond your budget unless you get lucky hunting for used equipment, and may require a cascade of upgrades you hadn't planned on, which increase the cost further.

You'd probably be better off saving up for a new bike--bike manufacturers are able to get parts at much lower cost, so when you buy a complete bike, you're getting the parts more cheaply than you could get them as an individual.


Does seat post suspension reduce efficiency?

Seat post suspension is not designed for efficiency.

It is designed to add comfort to a hard tail mountain bike frame. There are only a few really good suspension seat posts, and they are rarely used on hybrid bikes. Almost always, you will find that the suspension post on a basic hybrid is just a spring in a tube.

Occasionally, they add the ability to pre-load the spring to make it feel stiffer, and that is a slightly better option.

On that type of suspension post, you affect your efficiency when the post is active because your seat height will change as you ride, and as the post compresses. This will change your position and leverage, and usually, not for the better. It will detract from the amount of power you are getting out of the system, while still using the same or more energy to put in that power.

A true full suspension will account for most of these factors, and is therefore generally a more efficient choice, but weight, cost, and designed riding style for a bike will also affect the efficiency.

To directly answer your question, yes, you would be more efficient without a suspension seat post, assuming all else was equal.

However, most hybrids are lacking in any number of areas in regards to efficiency, and you may not feel the actual difference in efficiency from the seat post given the bike you are riding.


Job completed - it worked well.  Starting off with the finished product:

Start by measuring accurately.  I put a bottle in each cage and then tested placements, considering the band-on clamp for the FD and the toolbag I have in the front of the frame triangle, which lead to a slightly high seat tube position, and a slightly low downtube bottle.

Then I used a self-powered punch to put a divot in the center of the tube.  Be accurate!

Upper seattube hole is drilled, lower one is part drilled.  I started with a 2mm bit, then stepped straight to a 5mm and finished with a 7mm.  Probably better to go 2mm, 4mm, 6mm, 7mm.  I tried to catch the swarf with grease, which was only moderately successful.  I also tried a magnet, and a greasy paperclip in the hole to fish out swarf and chips.   See painting comment.

Close up of hole.  The edges are slightly raised, and as Mikes pointed out its not a flat contact area.  So (no pic) but I gently filed that lip off, and flattened the edges of the hole at the 12 and 6 oclock position to help the insert sit flatter.  It worked well.

Here's the nutsert / rivnut / insert about to go in.  Its got a light coating of clear epoxy on it, which may not have been needed.

When drilling, it was easy to drive a bit hard and clonk the drill bit into the far side of the tube.   The tapered reamer didn't work for the same reason.   So to protect the bare steel I sprayed some zinc-based paint on the edges, and into the hole to hit the far side.

Finished fitment.  The paint's not great (okay its pretty awful) but the insert sits really close in and has no problem with M5 bolts.

Here's the top-side of the downtube before bolting on the cages.

Last comments

if you're going to buy the tool, don't buy a cheap one.  Mine was $30 and the circlip failed on the last insert. leaving the tool's axle loose.  Aim to spent at least double what the cheapest tool costs.
David points out that its possible to do this with a QR skewer - but I had to use a lot of force on the end of a 250mm arm.  A 30-40mm Quick Release lever wouldn't be capable of this.
Drill the minimum-sized hole possible.  Use vernier calipers to be sure.  I ended up wiggling the drill bit fractionally to get a tight fit without stepping up to the next drill size.


Is there something particularly wrong with exclusively riding a mountain bike in a city setting?

The question of big box bike quality to one side, the question should be not whether it's "appropriate" to ride this bike, but whether you like it.

Are you physically comfortable riding the bike? If so, great! If not, there are several questions here about bike fit that may help you get comfortable on the bike. A bike that doesn't fit you will never be a good bike for you.

Is the new bike reliable and in good shape? Things to check: Do the brakes work reliably? Does the bike shift well? If not, bring it to a bike shop and have a mechanic look at it.

Mountain bikes are great at navigating potholes and are good city bikes because they accelerate quickly. (That last is great for when the traffic light turns green - zoom!) They're also easy to outfit for snow and ice.

If you're concerned with other cyclists' thoughts on what's "appropriate"... well, that's their problem and not yours at all. If you like the bike, I suggest you ride it and enjoy it.


E-Bikes - Is it bad for the bike to run out of battery?

Most rechargeable batteries have a certain voltage threshold below which they will get permanently damaged. Li-ion cells should never drop below 3.0V (slightly higher at 3.2V for LiPo). Smart batteries have integrated systems monitoring remaining voltage and will have a way to at least tell you they're getting too low.

In your case, it seems the system has a way to shut off electric assist but keep low-energy functions going for some time. I'm surprised the manufacturer could not give you a definitive answer, but I would expect the battery to be fine.

If you can get the specifications of your battery pack, you can divide the total voltage by the nominal voltage of one cell. For li-ion, that's 22.2V in a 6S pack so 6 cells of 3.7V in series. Multiply 3.0V by 6 and you get 18.0V. So if your E-bike has a display with remaining voltage and you're still above 20V, you shouldn't have a problem. If the system's smart, it will cut off the assist well before it gets to a critical point anyway.

Just make sure to recharge the batteries and not let them low when in storage.


what features do I give up if I buy the mechanical disc brake caliper costing one fourth that of another manufacturer?

It depends a lot which specific brakes you are comparing.
If you are looking at $100+ brakes they are probably hydraulic. The high-end market for cable disc brakes is limited because hydraulic seems to be taking over. You can still find boutique brakes like Paul brakes, and there is the Hy/Rd brakes from TRP which cost slightly more. The question of whether to use hydraulic brakes is a discussion unto itself. Hydraulic is favored for low lever effort and not having to be adjusted under heavy use. However hydraulic is also more expensive and has disadvantages of more complicated setup and requiring more special tools and parts.
Within cable disc brakes, the biggest disadvantage of very cheap (generic) cable disc calipers is that sometimes they don't work well, and you may have a hard time finding pads that fit once your current pads wear out. I'm talking about truly generic calipers here, meaning they came with a bike, or they are $10-20. The low end offerings from Shimano and Tektro are in the $40 range, and they work fine. Then again some types of cheap calipers use common (i.e. Shimano) pads, so it really depends on your specific brakes.
Anecdotally, I bought a cargo bike with unbranded mechanical disc brakes. The brakes required too much lever effort for my taste, so trying to improve them, I first replaced the cables with compressionless cables. Then I upgraded to oversized rotors. The brakes were better, but then I installed Shimano cable disc calipers, BR-M375. The brakes became immediately much better and I am very happy with them several hundred miles later.
I bought a different bike with Tektro mechanical discs and the brakes are great. I would say equal to the Shimano. Neither the Tektro nor Shimano calipers are very expensive..$40-50 each. For $60 each you can get TRP Spyre or Spyke brakes which have some nice features but won't really work better than the $40 Shimano.