That's the mount for the Flow Control valve on the Specialized AFR Shock.

The shocks with flow valves came stock on the higher end models of the 2007 Stumpjumper FSR like the Expert, Pro and the S-Works Carbon frame:


Sudden deflation of a mountain bike tube without a bang?

You say that both tyres deflated suddenly and you pumped them up on Sunday from flat.

I think the sun has caused this in one of maybe two ways. If both tyres were flat on Sunday because they had slow punctures, then when they were out in the sun all that time, they got hot and the pressure increased. That increased pressure made the slow punctures into much faster punctures until all the air was gone.

Or... one or both tubes were fine, but the heat from the "scorching sun" simply caused both tubes to go flat by heating up a section until something gave way. The only surprise is that you didn't hear a bang in this scenario, which would make it seem less likely.

Lesson: leave your bike in the shade.

In either case, you want make sure that there is nothing sharp left in the set up to cause further punctures. Check the rim strip to see that it is in good condition. Check the tubes to find out where the holes are. This can help narrow the search for the sharp object (that's why people line up the valve with the tyre branding). check the tyre and remove any sharp objects. Replace tyres if they are getting too thin to stop punctures.


Is a damaged BB7 inner caliper pin dangerous?

I think the only purpose of the pin is to retain the pad. So if you can convince yourself that the damaged pin isn't preventing the pad from sitting cleanly agains the "piston" and that it is prevented from dropping out, then I would be inclined to think you're ok.

I've seen instructions for rebuilding BB-7 calipers, which makes me think that parts might be available – at least in some markets. The SRAM/Avid number for the "internals kit" is A150080A and they appear to be available, I found links to the kit at shops in the UK, in the US Amazon lists the item, but doesn't have stock. In any case a whole new brake assembly isn't too expensive (considering that you get a set of pads and a disk as part of the deal), so if you have any doubts I'd just go ahead and replace the caliper (or see if you can get parts).


If you did 65km (40 miles), then after recovery (maybe 1 week) you can probably do that distance again with much less discomfort.  You should then be able to increase your mileage about 10-20% a week, if you get in one max-length ride and one about 1/3rd shorter each week.
Conveniently, I've found that you can usually, if you push yourself, ride about 50% farther than your "accustomed" ride (though you will be dragging at the end).
You do need to eat and drink on a long ride.  I'm a big advocate of this stuff called "food" for that (hopefully provided for you on your ride), though it doesn't hurt to have some sugary snacks.  And did I say DRINK?
90 RPM is probably a hair too fast.  But you do need to keep your cadence up, especially as you begin to tire.  20k/h (12.5mph) is not a terribly fast pace (even allowing for rest stops), so it's important to not burn yourself out trying to maintain a fast pace.

Ultimately, for 180km (112 miles) you will be running on empty near the end -- that distance is challenging.  But by slowly working your endurance up you can probably make it.  DON'T expect to do it with "tricks", though -- the most important thing to do is to just steadily increase your distances.


Why are chainrings 50T and larger five-bolt rather than four-bolt?

TL;DR: It's just marketing.

In the 1930's, René Herse used three-arm, 70mm BCD cranks, and you can buy 50T chainrings today that fit that specification. In 1949, Stronglight introduced the Model 49, that bolted the big chainring to the crank with a tiny set of five bolts near the spindle, and then bolted a secondary chainring directly to the first. In 1958, Campagnolo introduced big 5-arm cranks (151mm BCD!).

Mostly everyone adopted and refined variations of the five-arm design for the next four decades (TA tried six bolts for a while), until Shimano introduced the 4-arm XTR crank (112mm BCD) in 1996, followed up by more 4-arm cranks (104mm BCD) for LX and XT in 1997.  The marketing reason was that they were lighter (slightly), but it also meant that Shimano was the only company selling chainrings to fit the nascent standard.

Shimano was the 800lb gorilla of the 90's MTB marketplace, and where they went others followed. Over the next decade, 4-bolt cranks became common in mountain biking, where smaller chainrings are the norm. Hence the lack of large chainrings in four-bolt patterns.

Attempting to make the same leap again, the 2013 Shimano Dura Ace 9000 road crankset uses a non-symmetrical 4-arm crank with a 110mm BCD and up to 53 teeth. Once again, the stated marketing reason is weight - apparently this crankset saves 12 grams over the 5-arm Dura Ace 7900 crankset.

Much reviewers ink has been spilled over the stiffness of the new four-arm design and it's underlying strength, but it's not really clear that the cranksets of today are dramatically superior to those 3-bolt cranksets of the 30's, which were used to power tandems to the top of the Poly Chanteloup - and modern reproductions of those cranks are still lighter than the modern Dura Ace cranks.

More reading: Jan Heine's History of Aluminum Cranks, Stronglight 5-arm crankset timeline,  Museum of Mountain Bike Art & Technology Shimano timeline, Cycling News Dura Ace 9000 review


Faster Wheels & Tyres for my Cyclocross bike

Its not the size of the tyre, its the knobliness and the rolling resistance.

Assuming 35 is the tyre size then you have a 15-24 mm rim, based on this DT Swiss PDF  and maybe could go as far as a 20mm tyre.  This is rim width dependant though.

Realistically, a smooth 28-25 mm tyre will give you a more comfortable ride than a narrow tyre, and will roll just as fast if not faster.

CX bikes are fine for commuting - a road bike might be slightly faster but often takes away things like fender/mudguard mounts, or rack mounts which add to the overall comfort of your ride.


In track (velodrome) racing, visible cycle computer displays are generally not permitted. So the only funny looks will be from the commissaire who will request it be removed.

This is the UCI rule:

  UCI CYCLING REGULATIONS TRACK RACES

  3.2.005 Riders may carry no object on them or on their bicycles that could drop onto the track. They may not bear or use on the track any
  music player or radio communication system.

  In addition, any electronic device with display (for instance
  speedometer or powermeter) must be hidden to that it cannot be read by
  the riders.

My track bike has an SRM power meter and SRM Powercontrol bar mounted computer. The display may only be used in this manner for training. I used to use an under saddle mount for racing so I could still record the data. In the early days of this rule being implemented I was able to use a cover on the display to comply but that soon gave way to no devices permitted on the handlebars. Then we started to put computers on the top tube behind the head tube, and that was frowned upon as well. So we moved to under saddle mounting sort of like this:

GPS is of course useless on indoor velodromes, and not that great on outdoor ones as its resolution when changing direction is not that great. If you ever look at the map plot from a GPS device of a bike ridden around a tight enough curve at a decent speed, like on a velodrome or descending a twisty road, you'll see the track plotted by the GPS data cuts the corners. Speed is assumed to be the straight line distance divided by the time interval, when actual distance is around a curved path.

This is why on tracks we prefer the use of wheel speed sensor. Better precision, resolution and accuracy in wheel speed measurement. Of course wheel speed on a velodrome doesn't equal bike speed, since the wheels travel a different path to the rider (wheel follow a larger radius arc due to the lean angles involved in riding on a track).

It's possible to compensate for this with some maths and knowledge of the track's geometry. It sort of depends on what you need the speed data for. e.g. for aerodynamics testing you really want to know the velocity of the rider relative the surrounding air, and not the speed of the wheels since it's the rider that makes up the bulk of the aerodynamic drag.


Has the Mongoose Black Diamond 2 Frame been released?

Answer No (as of 2018-02-07)

There is a mongoose Black Diamond Double in 2008 which looks like this, but the pivots are in different places.

Second data point is that the top google match for "mongoose black diamond 2" is this question.  So that is a good indication that it doesn't exist by that name.

Its very hard to prove the non-existence of something.


What are some notable visual observations one can make of a cassette that indicate wear? And to what degree that wear has progressed?

Chains wear faster than cassettes, so check the chain wear first. A simple chain wear gauge is cheap and gives a accurate indication of wear - or at least it will tell you if the chain is worn out or nearly so.

If the chain is OK then there is a higher chance that the cassette has not been used with a worn chain. Riding with a worn and elongated chain accelerates sprocket wear.

I cannot see any bad wear on the cassette. Hard to say how much life it has - it totally depends on your riding style. I say install it and try it out. If it skips or you have poor shifting try a new cassette and chain. You won't loose anything by giving this one a go.


Yes there is one main trick, and some regular skills.

The trick is: if you LOWER THE TIRE PRESSURE, any tire will float over sand like magic. It should not be so underinflated as to allow easy pinch flats, but the lower the pressure, the more marked the floating effect. There are just two limitations:

If the tire is skinny (low volume) it might not be possible to have a pressure level that allows flotation AND safe riding over rough terrain on other trail sections;
It's not possible to adjust tire pressure "on the fly" ;o)  But if you know you're having a long stretch of soft terrain, it's possible to have a good trade-off.

Anyway, huge tires (2.3 +) are perfect for that (watch this Surly Pugsley video). Also, knobby doesn't help that much, sometimes slicks are better; they cause less shearing of the sand and rob you of less kinetic energy.

Now the skills are mostly help maintain speed and direction.

Speed: not so fast as to suddenly throw you over the bars in case of loss of control, not so slow that your rear wheel loses traction in order to maintain or recover speed.

Direction: plan ahead the smoothest possible trajectory, and point your front wheel firmly along that trajectory. Avoid wobbling on the pedals, major gear changes, and specially avoid sharp turns, because there is a critical steering angle above which the front tire skids sideways and the bike becomes unstable, making it almost impossible to regain control in some cases (of course the more skill one has, the more one can recover from).

Hope that helps and... PRACTICE! Few things can be more fun than that!


On the whole I think it is best to not approach drivers when out cycling.  Sometimes a 'near miss' is unintentional, sometimes it is due to carelessness and sometimes it might be intentional.  The trouble is, from a cyclist point of view it is often hard to tell which it was.

When approaching a driver after an incident it is difficult for the situation to not become confrontational.  In my experience it is therefore safest to try to remain calm and just get on with your bike ride.  Approaching drivers after an incident has never resulted in me coming away from the incident feeling better, and has never improved my enjoyment of the bike ride.  Generally incidents result from something outwith my control, and I find it best to just forget it and get back to enjoying riding my bike


Highly unlikely that a mismatch between the rim width and tire width is causing flats. I would hope that if your rim was too wide for a 23mm tire and would not seat properly the bike shop would not have installed it.

Note that on a trainer you have a much greater margin of error with tire sizes because the rear wheel isn't taking very much radial load, and no lateral load.

The first thing to check for if you are getting frequent punctures is a problem with the rim tape exposing the spokes or nipples or another sharpe surface inside the rim, or a foreign object embedded in the tire that is abrading the tube. As you have a new trainer tire that has never been ridden on the road the latter should not be the case.

Lining the tire logo up with the valve and keeping track of where punctures occur on the tube can help track down the location of whatever is damaging the tube.

You say that you are getting flats, but not specifically punctures. If the tube is just deflating either a small slow puncture or a faulty valve is likely the culprit.


You can get explicit cycling knee warmers - I have a pair of these which see a lot of use (and sometimes go under jeans, very comfortably, if I'm out of an evening too). They are great for the morning commutes where it is cold but likely to be warmer by the time of the return journey, but also for the longer rides where you start colder than you'll finish and you need the flexibility to remove bits of kit. You can get fleece lined versions which are even warmer.

They're not cheap - but there are other cheaper alternatives designed to a similar style.

They don't offer explicit knee support, but if you need support for your knees when going about your day, then I doubt a cycling Q-and-A site is the best place for your question.

Similarly, if you think your cycling is causing your knee pain, I'd recommend a visit to your local bike shop and ask them about whether your bike is fit and adjusted properly.


What to prepare for a long distance ride (1600km)

I took part in a charity ride from Scotland to Italy in June last year, and that was made a lot easier with the use of a support team to help carry everything. Since you are going it alone, you need to consider quite a lot of things:

Directions

It's fine planning a route, but they often don't go to plan. Always be prepared to make alterations at the last minute. A detailed road map of the area / GPS device is essential for this.
Know roughly where you're going to end up at the end of each day. Plan ahead and maybe pre-book your accommodation. Most places allow you to reserver a room for free and pay when you leave, so it comes at no initial cost. If you don't make it to a given town, find somewhere else to stay. You suggest camping in a tent - although feasible, bear in mind the amount of kit you may already be carrying.

Nutrition

Undertaking long mileage takes its toll on your energy levels, so its important to replace the calories and replenish water loss. You can carry sandwhiches or even pop into cafés, but another alternative is the use of energy gels and flapjacks etc. These are easy to carry and provide enough fuel to keep you going.
Hydration is really important, so carrying water or some other hydrating fluid is essential. Try mixing it with energy drink powder to hydrate and keep your energy stores up.

Spares / Tools

Long-distance cycling takes it's toll on your bike, but also increases the likelihood of hitting a problem along the way.
Carry a set of bike tools such as a chain link tool, spanners, hex keys to help you make adjustments and repairs along the way.
Inner tubes, tyre levers and a puncture repair kit (and a pump!) are also vital. You can always find a petrol station or another cyclist to help, but be prepared and be self-sufficient with repairs.

Clothing

Take a variety of clothing to help with the different weather conditions. There's nothing worse than getting into wet clothes when you could have had a dry set to hand.

Waterproofs

Hot-weather gear
Base layers

If I think of anything else I will add it to the list, but these are some of the main things to consider that I can think of.


Is there a possibility to mount a 2014/2015 Croozer Cargo trailer hitch onto a 2012/2013 model?

Maybe.  It depends on differences beyond the hitch system for the trailer.  Best bet is to find the model you want to upgrade to and take measurements and compare.

Typically you will find that the trailer tongue is made of plain tubing (be it square or round).  I doubt that this will change much between model lines and years.  What will change is probably the various bends in it to give the tire some clearance.  The important part is that it is the same size tube on the inside (or really close).  The hitch parts are then inserted into the tube and secured with a nut and bolt.  If the inner diameter is good and the securing bolt is in the right place, make the swap.

I have done such swaps on both of my trailers.  My kid trailer is a Pacific Voyager 2 and the other is a generic cargo trailer (happens to be a Asom Wonderer, but other sell it as well).  Both trailers had a spring that came out of the tongue into the quick release assembly which then attached to the component that is mounted on the bike.  It ends up that both trailers have tubing that is the right size for the Burley systems so it was a quick swap.  All I did was undo the bolt, slide out the spring, then add the flex connector and bolt.  Here is a picture of the setup from my cargo trailer:


Because wind resistance is proportional to velocity squared it takes more power to go from 30 to 32 than from 15 to 17.  So you get more bang from your pedal power at lower speeds.   If it is a relatively short downhill and you have considerable speed you are typically better off coasting and then pedal when you get to a flat or flatter section.

So you are better off exerting yourself on the lower speed ascent.  Then recover on the downhill.  It might be 2 minute recovery or 20 minute recovery.  If you notice racers typically go all out on the ascent.

If you went up the hill at 8 mph and down the hill at 13 mph compared to a constant 10 mph you would have about 5% more wind resistance.


Training fasted: just about weight loss?

Advice in book Racing Weight by Matt Fitzgerald goes something like this, paraphrased:

Yes, training without carbohydrates will train your body to use stored fat better. But your capacity to train will go down (not enough fuel!), and net result will be less improvement.

It references this study, which compares two groups of athletes on hi-carb and low-carb diet during a hard training block.

One of the general themes of the book is, you want to improve your performance and body composition, not your weight per se.


I have seen numerous people riding down the path with a sound system on their bicycle. Without exception they use the simplest and most portable solution: a bluetooth speaker. This meets all of the requirements of outdoor usage:

Self Contained
Waterproof
Long Battery Life
No wires to run
Lightweight and portable
Inexpensive

Tie it to your bike rack and pair it with your phone. I've done it myself once, but be warned, you will need a louder one outside (especially at a critical mass ride). So you may have to invest in one of the larger models.


How to relate wind chill, temperature, and cycling

Ok, let's start with wind chill.  The faster the wind, the more chill Wind Chill chart from the National Weather Service Read along the top for the temperature without wind, then down for wind chill at different speeds.  So, for example, at 15 degrees Fahrenheit (-9°C) in a 15mph (6.7 m/s) wind, effective temperature is 0 degrees Fahrenheit (-18°C). (chilly!) That chart only works up to 40 degrees F (4°C), but it gives the idea! This Wind chill Calculator allows you to put in any value, and speed of air

Of course, that's if you're standing still.  If you're cycling you almost always have a headwind, Here is a link to a page with masses of detailed information about headwinds.  The faster you go, the faster the effective windspeed, and the lower the temperature felt.  This can be really helpful on a hot summer day, or really chilly in a cold winter!

When cycling you have to take this into account - in the winter, layer up (and find a wind proof jacket if possible.)  In the summer, it means that you can actually go up that big hill without totally overheating! I remember one hot day, on a steep incline, I rounded a bend, and came straight into the lee (wind shielded) side of the hill - in seconds I was feeling way too hot, without the cooling breeze.


Require seatpost size of Dahon Vitesse D7

Go to a bike shop and get it measured.

They'll have some seatpost measuring tool like this:

You basically stick it into the seat tube and it tells you what size seatpost you need.

Alternatively, you could use a vernier caliper to measure the seat tube diameter on the inside (this is key!).

Note that the seat tube diameter is only one dimension; you also need to know what length tube you need. Most seatposts have the same clamp type as well, but you may want to get one with extra fore/aft adjustment or whatever. So, going to a shop and buying one isn't a bad idea if you don't know what you need.


Trying to purchase the correct handlebar faceplate bolt in advance for Schwinn S2713TR

You really need to take the remaining bolt to the hardware store and get them to match something with the appropriate length and thread pitch.

This isn't a standard length or size, but its likely M5 or M6 with length somewhere between 15-25 mm. You'd probably end up buying at least 6-8 packs of bolts to find the right one without measuring the existing one.


On sand you'll need wider tires that do not dig into sand as easily as well as some tread pattern to prevent sand grains from rolling under your tires. 23mm is too narrow.

Measure the forks, if they are wide enough you can use cyclocross semislicks. I have seen an old Trek road bike with cyclocross tires used in a race, so it might be possible for your bike too. Narrower touring tires are an option too, get the widest that you can fit.


How can I ride a bike having severe spinal disease and pain?

I would think some sort of a tricycle would be the best choice for you, probably a recumbent.

Something like this is the first thing that comes to mind:

You lay in a reclined position and pedal with your feet in front of you.  These come in several variants, from fully reclined (such as the above) to more upright.

There are also numerous variations of the hand-powered cycle, and some that are operated with both hands and feet such as this one:

Some of these are "stock", while others are fairly highly customized "one-off" bikes.  (But several versions of the basic tricycle recumbent are available "off the shelf" at relatively reasonable prices.)

I never seen any of these bike styles with an auxiliary motor, but I'm sure there are some.  Several battery-assist systems are available for standard bikes and could be easily adapted to a recumbent.  A full-power gasoline engine would be a bit more complicated.


Preventing my trunk-mounted bike rack from being stolen

The metal brackets that clip on the edges of the trunk lid cannot be removed when the trunk is closed and locked, so no-one is going to casually unclip the rack and walk off with it.

I suppose someone could lever the brackets out, but that would damage the trunk lid and surrounding bodywork, so you would have a bigger problem and an insurance claim.

Also the straps could be cut, but what is the point of stealing a ruined rack?


What is a good way to keep my tires from going flat easily?

There are a number of things you can do:

Puncture resistant tires.  These have kevlar/aramid belting in the tire, thicker rubber or other features that make them harder to puncture. Would need to know more specifics about your bike (especially wheel/rim size) to be able to suggest specific tires, but Specialized, Continental, Schwalbe, and pretty much every other major tire manufacturer have a wide range of puncture-resistant tires. You can probably just go to your local bike shop and ask about puncture resistant tires, or you can order them online a number of places. There's a bunch of good suggestions here for specific types: What type of tires can prevent goatheads?
Puncture resistant tubes.  These seem to be harder to find.
Slime/goo in the tube.  Personally I don't care for this, but some people swear by it.  This is a sort of thick goop that goes inside the tube; small punctures will get filled in by the goop.
Tire inserts.  These are kind of like a belt that goes between the tire and the innertube, stopping sharp pointy things from going into the tube.
Keep tires well-inflated (near the top of the recommended pressure).  This reduces the size of the contact patch and makes it more likely stuff will glance off the tire. You didn't mention them in the question, but this also prevents pinch-flats.
Avoid riding over sharp pointy things, especially when there's water around.  It's much easier to cut or puncture rubber when wet, since dry rubber tends to grab glass and metal.

Also, if you do get a flat, make sure to check both for remaining pointy bits and gashes in the tire large enough for the tube to herniate out through.


Would a IGH drive train last longer than a derailleur drive train?

A chain used in a single sprocket configuration should outlive a chain used in a derailleur system because it always runs straight between aligned chainring and sprocket.

A 1/8" single sprocket chain will last longer than a 3/32" derailleur chain because it has larger bearing surfaces between pins and bushings.

A cassette is likely to last longer than a single sprocket because wear is spread over multiple sprockets. Same applies for multiple chainrings on a crankset.


Can I swap out an Ultegra 6750 crankset with a 6700?

The spindles should be the same width and diameter. Seeing as how you already have an Ultegra crankset, you should be able to use the larger Ultegra crankset without switching the BB or getting an adapter. But you will have to move the front derailleur up and probably re-cable it. Switching will make you have to constantly move it so you'll have to leave enough at the end when you're in compact so it'll fit when you move to standard.
If you're looking for more gearing but don't feel like switching everything back and forth, you could always switch to mid compact chainrings (52 x 36).  They use the same BCD as compact and it should be once and done without having to move your derailleur every time you switch.


Chain size designations e.g. 1/2 x 3/32 : how to measure?

a) the thickness of the spacer between the inner links
b) the distance between the inner links

Those two measurements are the same thing. The roller (spacer) sits between the inner plates, so its thickness is the spacing between the plates.
If you look closely at the inner links the inner edge is chamfered, making it difficult to measure the actual distance between them - I guess that's why you are coming up with different measured widths. Measuring at the roller is more accurate.
So, I guess you have a 3/32 chain.


What is the difference between race/road and cx bikes?

Cyclocross bikes will have a slightly different geometry. More like a relaxed road geometry with a higher bottom bracket than a road bike typically. You'll be stretched out a bit less and more upright. Cross frames also will have wider tire clearances for 32mm to 35mm tires, but it varies by model as some can fit 38mm to 45mm tires.

Traditionally, brakes tend to be wide profile cantilever brakes for good tire clearance and less chance of clogging with mud on cyclocross bikes.  However, disc brakes are now readily available on many cyclocross bikes.  Road / Racing bikes tend to use caliper brakes which have better modulation, but typically have small tire clearances, which may be too restrictive for cross tires, especially when they are covered in mud.

The new standard rear wheel size for disc cross bikes seems to be 135mm, so it's the same as mountain bike disc hubs. Non disc cyclocross bikes tend to have rear hubs which are spaced at 130mm, the current road standard hub spacing.

Tires on a cross bike are going to be different as well.  Road bikes will typically have skinny 23mm to 28mm slicks.  On a cyclocross bike, you will typically have knobbier tires which may not last as long and provide more rolling resistance when compared to road tires, which is a tradeoff for having better handling on dirt / grass / mud.  You can always swap out tires to match whatever style of riding you prefer. Depending on how serious you are about racing, you can find both cyclocross and road tires available as glue on tubular tires.  However, some people have been adapting mountain bike tubeless technology and mounting cross tires as tubeless to run lower pressures for better offroad handling. It is not common to use the mountain bike style tubeless setup on a road bike, and generally not desirable.

Road bikes and cyclocross bikes tend to use STI shifters and similar groupsets (chainrings / cassette / derailleur combinations), however sometimes people prefer to use bar-end shifters for cyclocross (or retroshift shifters which mount bar end shifters on brake levers).  Additionally, some cyclocross bikes have an extra guard on the outer chainring to prevent injury when mounting / dismounting frequently. These guards are typically not as heavy duty as mountain bike bash guards.

Cable routing tends to be different on cyclocross bikes due to the need to shoulder a  bike during the race, so under the top tube routing is typically avoided.  Sometimes 3 cables on top of the top tube or internal cable routing strategies are used.  Often times full housing will be used to help prevent cables from getting contaminated with mud as easily.


Is it possible to set this fork steerer / stem higher?

This is a traditional quill stem, meaning it's shaped like a "7", with the vertical part fixed inside the steerer tube by a wedge bolt.
There should be an allen bolt at the top--it looks like it might be covered by a rubber plug here. Loosen that and give it a light tap with a mallet to dislodge the wedge. You should then be able to raise the stem. If you can't raise it as high as you want, you could replace it with a new stem that's taller.


How to store tires in dry California summer

UV rays and ozone are the main factors behind rubber "drying out" -- look at how the Air Force stores its airplanes in the desert: all of the rubber bits are carefully protected from the sunlight.

So try to keep it in a dry area out of the sun, and not near any ozone sources (mostly electric motors such as an AC unit).

Note that it's also important that the tire not be subject to any stress or folding that might deform it. For example, if you left the tires on your bicycle over a long period of time, they would self-deflate (due to air migrating out of the rubber) and the very bottom of the tire and tube would deform against the floor - potentially damaging the tire and its casing.

Under the bed is just fine as long as it isn't subject to any pressure or deformation that might come from it lying horizontally while deflated. Hanging the tire (while on a rim) vertically on a hook off the ceiling in a dark place is perhaps the best but might not be practical for you.


Are there safety differences in helmets with ce marking?

Helmets sold in Europe generally must meet the CEN EN-1078 bicycle helmet standard that limits the amount of energy transmitted to the head during a series of tests using weighted head-shaped forms (around ~5kg) dropped from various heights onto flat or curved surfaces at different locations on the helmet. While helmets with the CE certification must meet EN-1078, manufacturers can choose to exceed the standard and have their helmets protect your head at even higher impact energies. A similar standard, the CPSC standard, applies to helmets sold in the US: all helmets must meet the CPSC standard but manufacturers can choose to exceed them and sell safer helmets. Although the CE and CPSC standards are similar enough that many manufacturers will aim to satisfy both standards so that their helmets can be sold either in Europe or in the US, there are subtle differences that mean that a few helmets may be certifiable under one standard but not the other. Larger manufacturers will test their helmets in-house, and swear to the CE and CPSC that their helmets passed; smaller manufacturers will often send their helmets to third party certification laboratories to do the tests. In that case, the certification laboratories swear that the helmets passed.

So although the CE and CPSC certification tells you a helmet met the standard, it doesn't tell you whether the helmet exceeds the standard (and, if so, by how much). In part, this is because testing is not done until failure; that is, manufacturers typically don't increase the height of the drop or increase the weight of the head-shaped form until the helmet fails. They drop the helmet at the standard height and weight and measure the energy transmitted to form. If that energy meets the certification standard they are satisfied and do no further testing.

Worse, you cannot use the price of the helmet as an indicator of "safety." Helmets are generally marketed by how much they weigh, how many ventilation holes they have, the colors available, how aerodynamic they are, whether they come with visors, celebrity endorsements, and, of course, how much they cost -- but not how much they exceed minimal standards of energy transmission. That is, manufacturers will gladly provide information about almost every characteristic of a helmet except for how well it will protect your head.

In the US there are a few independent research institutes that will test bicycle helmets but they tend to test expensive helmets, not the least expensive ones. There may be similar helmet testing institutes in Europe.


From your photo I think the bike is a bitser, and without decals/names/markings its very hard to identify.

The front fork is clearly labelled Giant and has straight tines so its relatively modern.  Possibly a carbon or aluminium alloy fork, it doesn't look like a steel fork.  Fork is also painted completely different to frame, so they're not originally together.  Fork is also threadless at the top, which is quite modern.  The frame would have had a quill stem when new.

However the hoods and brake levers are 80s or possibly early 90s.  They're not combined brifters, the shifters are on the downtube which is completely 80s.

The horizontal top tube looks 90s when considering its aluminium alloy.  Thicker walled aluminium was used when it was a new material for framebuilding, and hydroforming wasn't possible so strength was added with bulk.

The rear wheel cutout in the seat tube is for aerodynamic reasons - it smooths the airflow a bit, but the main advantage was to permit a shorter wheelbase while retaining 700c wheels.

The road double chainrings are not a compact, instead they're quite close together in size.  Not sure what that implies, other than few hills.

Identifying steel is easy - touch it with a magnet (like an old hard drive magnet) and see if it attracts.   Aluminium or titanium won't attract a magnet.  To tell Aluminium from Titanium is harder - neither require painting.  Titanium will spark a lot, bright blue/white when touched with a grinder, and aluminium won't really spark at all.

If you can get to a bare piece of metal, apply a moist cathode (paper towel) to the positive-attached metal. 9v should do to get a slight tan tinge. 18v (2x9v batteries) will take you to dark violet.  Some of these requires taking off a patch of surface coating, so not a first option.

Heres a 1998 mongoose road bike that shares a lot of features with your frame's design.  This one is aluminium, and has the original fork still.


What Bottom Bracket for a 2007 Rush Hour frame?

The frame is almost certainly a 68mm English-threaded shell.  Beyond that, the cranks you're using and the desired chainline determine the bottom bracket spindle length.

If the rest of the bike is stock, BikePedia claims that the crankset is a TruVativ Touro Track. The Truvativ Crankset docs specify a 108mm bottom bracket with that crankset giving you a 43.5mm chainline. Reducing that by a half millimeter or so by switching to a 107mm bottom bracket should be just fine.


Compatibility between Shimano 105 crankset and Shimano Deore derailleur

If you want to switch from a MTB triple to a road double crank you'll need to replace the front derailleur and shifter to get the correct derailleur movement.

Putting a road crank on an hybrid frame designed for MTB components is problematic:

You'd have to find a road groupset that also has compatible flat-bar shifters. 105 5700 does not, the latest lower end road Shimano groups do.

I think (from looking at old reviews of the bike) you have a Shimano Hollowtech II bottom bracket. You very likely have the wider MTB version that fits on 73 and 68mm wide shells. A road crank spindle is made for the narrower road BB version for 68mm shells only and is therefore 5mm shorter.

There is also the problem of clearance between the larger chainrings and the right hand side chainstay.


How to reduce brake lever rattling sound at the pivot pin either by a fix or by replacement?

The lever of this specific model is not replaceable. So you can try your luck with a thick grease, or by "inserting" some layer of foam, or gluing little patches of old tubes in between the lever and the housing, close to the rivet.
The rattling is happening because of some play between the parts. The weight of your finger is enough to keep the parts in contact ---> replicate that by putting some material in between.


Derailleur-shifters compatibility Shimano GRX

The rear pull ratios used by Shimano are:

SIS v1 for Dura-Ace 7400 only, which was about 1mm cable to 1.9mm derailleur movement
SIS v2 for everything excluding that, up to the introduction of 10-speed MTB (i.e. including 10-speed road, which came before 10sp MTB), which was about 1:1.7
Dynasys / 'New MTB' - which was introduced for 10-speed MTB and kept for 11 & 12-speed, which is about 1:1.2
'New Road', which was introduced for Shimano 11-speed road, and subsequently used for all 10-speed road (which includes gravel) products introduced since the introduction of that, which is about 1:1.4

Essentially with ever more closely spaced sprockets, it emerged that while pulling less cable means a shift requires more force, it makes shifting more accurate/precise/easier to setup. Hence after the introduction of 10-speed MTB which pulls more cable per shift, and the introduction of hidden cabling for second-generation 10-speed road, which adds more right-angles/friction, Shimano came up with an intermediate shift ratio between MTB and the previous standard. Since the old ratio didn't work that well with hidden cabling & 10-speeds or more, they essentially have one standard that is used for all new 10 & 11-speed, and probably will be kept for 12-speeds as well.
So the RX812 is not '11-speed', since the RD is not indexed. It will work with shifters that use Shimano's new road pull ratio, which is anything GRX (10 or 11-speed), anything 11-speed, and Tiagra 4700 10-speed.
There are some older 10-speed road shifters using the standard-for-everything-for-a-quarter-of-a-century-pull ratio, but they are no longer in the Shimano range.
The thing specifically with RD-RX812 is it's marked for a 1x drivetrain, and Shimano don't have 1x levers for road (only for gravel), so they only show it compatible with the GRX levers, since these have brake-only levers. There's however nothing stopping you using it with, say, SL-4700-R, which is a flat bar 10-speed lever, and a Deore 10-speed 11-42 cassette.


Rebuild or replace rear wheel on Giant Escape 2 (2016)?

You're not peloton-svelte, so I'd recommend a 36 spoke rear wheel/rim that otherwise duplicates all the measurements of the stock rim.

More spokes is a stronger-better wheel.  40 and 48 spoke is also possible, but they're a bit more rare.

A $500 USD bike is better than a BSO, but it will still have average wheels at best.   An upgrade to the rear wheel is a good idea, if you like the bike and it fits you well.   Shop around, you might find a pair for fair price, being not a lot more than a single.

The other option is to buy a rim/spokes/hub separately and have a good LBS build it for you.


A 3x8 crank will work with a 7 speed system. 7 and 8 speed chains are the same, as is the spacing between the chainrings.

The Claris crank specification can be found on the Shimano Manuals and Technical Documents site   here. The FC-R2030 seems to only come in 50-39-30. If that is larger than you current crank you'll need to check that you have sufficient clearance with the drive side chainstay.

The specification says the FC-R2030 works with either a 68 or 73mm bottom bracket shell, so that will work whatever your bike has. Note it also says what bottom bracket you need (BB-RS500) that will fit either shell width.

The FC-R2030 provides a chainline of 45mm - that's the standard for road triples. You'll definitely want to check that that is what you bike runs as there's a chance it runs the mountain bike triple standard 47.5mm. Measure from the center of the seat tube to the middle ring. More info here https://www.sheldonbrown.com/chainline.html.

If you have 47.5mm chainline you'll need to look at a mountain triple crank instead of a road triple crank.


Using only the brake lever, separated from an integrated shifter/brake

You can use the brake lever without the shift portion just by disconnecting the shift cable. Then, you can attach a bar end shifter or a downtube shifter or similar to shift instead.

You won't be able to replace just the shifter portion of the brifter (without probably canabalizing another brifter anyway and actually manage to put the old one together).

You can also buy a 7 speed or so brifter from Microshift still which is Shimano compatible, or the Shimano Tourney 7 speed brifter.


How to get the rear wheel off Pure Cycles bike

The nut in the orange circle is what you need to remove on either side of the hub, there should be no use for a hammer in this application. Simply use an adjustable wrench on either side and remove counter clockwise.
The yellowish green arrow points to a tensioner screw, which helps to tension the chain and properly space the axle in the dropout so that it is equal distance on either side.
The blue oval is an issue, your chain should not be doing this and i'm not sure how that happened. Is the chain off the front chainring so that it is loose i assume? I would roll the wheel forward and fix this chain hang up before removing the wheel so that your not fighting it when you try and slide the axle back and out of the dropouts,


The best upgrade is the one that solves a specific problem or replaces a worn out part.
Changing out any part on your bike should be done with a goal in mind. Your goals should be determined by identifying some specific way your bike could work better for you based on your riding style, terrain and personal goals. A "good" upgrade for one person could be a terrible modification for you.

Based on this premise you need to evaluate what specifically disappoints you about your bike? Here are some examples:

My riding position is not comfortable
I don't seem to have the correct gearing to meet my needs
My bike has a very rough ride.
My brakes are not performing to my expectations
There are many possibilities.

Once you identify the need, or the goal you can ask a specific question and gain specific answers. The other benefit is that you can know if the change you made met your goal.


A total spacer height of 30mm below and 5mm above is quite typical, and certainly nothing to be worried about.  The most important thing, since you have a carbon steer tube, is to make sure you use the proper compression plug and the specified amount of torque when assembling it.  Also make sure the top of your top spacer is just slightly higher than the top of the steer tube, because the top cap needs to rest on the spacer (or stem), not the tube.

Don't forget you can achieve some bar height adjustment by flipping the stem, too.


Help figuring out make/model/year of this bike?

Given the bottom bracket type, the thin pressed dropouts and the type of seatbinding bolt used, this was not originally a particularly special bike.

It looks like a well-done refurbishment. Look after it, enjoy it, but if it gets bent or stolen, don't worry too much about saving it or restoring it again.


That's Shimano's C050 rear derailleur. It is comparable to Atlus and Tourney in quality and I believe only came as a 7 speed, like yours.

I've attached the technical manual so you can see how to set it up properly. If you're looking to replace it, Shimano provided a lot of high end 7 speed rear mechs. For a mountain bike that would include things like exage, deore lx, and so on. The same time period for road and commuter bicycles would be exage, some rsx.


Standing on cottered crank scuffs bearings?

My experience in general with bearings (Wheel hubs mostly, and some bottom brackets) is that if they wear out too quickly in spite of being well lubricated and adjusted is either the ball bearings are poor quality or the races and cones are already damaged, or both.
Substituting caged balls with free balls allows for somewhat longer maintenance periods but not much (1.5x longer aprox).
When the races and cones are pitted, corroded, or deformed they wear the balls faster.
The other factor is that the bearing must be correctly pre-loaded (that is, the cones correctly tightening the balls against the races).
The only times I messed around with bottom brackets It has been square taper axles, and was having a similar issue as the one you described. At the time I used a low quality bike and the only replacements available locally where low quality parts. At first I thought the cups where unscrewing themselves, but took note of their position and no movement was apparent. However the axle developed play in about six months of about 4 days per week use, around 2-3 hours. (teenager, riding up and down small paved hills).
At first I tried using only the balls, without the cage, using as many balls as they would fit without the cage. But then I noticed the cups had small holes in the race (the channel where the balls roll) and also, the "cone" part of the axle had a "groove" made by using the worn balls too much.
The solution was to replace all the parts (cup set, axle and bearings)
My adjustment was to tighten the cups all the way until I felt resistance when trying to rotate the axle by hand, then receeding a quarter of a turn, then tighten the locknut. I had to try a few times until I got it right. (No play on the axle was perceivable by hand when forcing the crank arms, slight resistance to rotation due to the grease)
That was the last setup that I performed on that part of the bike and it where good for at least a year, when I "grew up" to MTB and got a new, better bike.
I would argue that standing on the cranks should not wear then any faster, at least if they are well adjusted and in good condition. On the other hand, using them while out of adjustment definitely makes them wear faster. (I had a bad experience with a cheap bottom bracket cartridge. It developed play but kept using it for commuting daily. After a month or two, the cartridge failed catastrophically leaving me unable to pedal and in the middle of a street right after an intersection)
Just for reference: here is an image showing the terminology I use. Please excuse me if the labeling is not correct.


"Tinking" Sound on my Force 22 PF 30, Ridley Fenix?

NEVER put grease on the seatpost of a carbon frame. CARBON FIBER ASSEMBLY PASTE is to be used there to prevent corrosion, seizing, and slipping. Grease inside the seat tube will make the post slip. Anyone who tells you to do that is not qualified to give ANY advice.

WARNING: NEVER overtighten anything clamped to a carbon fiber component.

Check tightness of socket head fasteners that secure the chain rings to the crank arms.

Make sure that THREADS of seat clamp screw are lubricated and that fastener is properly torqued; NO lubricant on post or inside seat tube, please.

The following is safety critical; a broken steerer tube can kill you.

Remove stem from steerer tube and take fork out of frame. Inspect steerer tube for scratches or cracks using bright light. Check for sharp edges on contact surfaces of stem opening and round them off with a file. When reassembling, use assembly paste on stem to steerer contact surfaces.  Make sure that steerer tube expansion plug is correctly installed and apply correct torque to stem cap bolt before tightening the stem clamping bolts. Lightly lubricate threads of stem clamping bolts and torque to specifications.

Take handlebars out of stem. Check for sharp edges on contact surfaces of stem body or cover plate and round off any such edges with file. Lubricate threads of cover plate bolts but don't get any oil or grease on contact areas between stem and bars.

Check for correct torque on pedals.

Check WHEELS carefully..
Borrow a set of known good wheels from a friend, and see if noise goes away.

Check own wheels for defects:

Look for rim cracks near nipple holes. Squeeze pairs of spokes to see if they are clicking at crossing points. Take wheels off, place on ground horizontally, and gently but firmly push down on rim at opposite sides of wheel.


700 is the size of the wheel and tire which the tube is intended to fit. In this case, 700 means 700c, or ISO diameter 622mm rims. If you are unfamiliar with tire sizes, take a look here.

28/32 designates the min/max range of width of the tire which the tube is intended to fit, in mm. So in your case, your tubes are designed to fit tires of width 28mm (minimum) to 32mm (maximum). This range should correspond to the width of your rim as well.

Edit: From @Benson's comment on this answer (in case it gets deleted)

  Using a tube that's too big will mean it's exceedingly hard to get your tire back on, because the tube will have to fold out of the way. You'll risk pinching and damaging the tube as you put your tire back on. If you use a tube that's too small, you'll risk the tube stretching too far, which makes it much more vulnerable to popping.


We don't usually supply lists of resources here, because they don't really fit with the general SE question-with-one-best-answer approach.

Interest in retro bikes and cycling gear is at an all time high, and so is the amount of information available.

I'm answering because I hope to give you, and others who end up here, an example of how this information can be found

In this case I Googled "1981 bianchi catalog" (press enter after following the link) and got a bunch of hits.

The best seemed to be Bianchi 1981 Catalog. It should answer a lot of your questions.

Many old catalogs have been digitized and can be found in a similar way.


brand new fixie, different sized dropouts - send back?

If the issue was just the 1mm difference in the dropout, I would personally just file it out and note it in the Ebay feedback.

With this one bent, contact the seller and see if there is a replacement/return option.  Failing that you could try to get a shop to bend it back and bill the seller.  If the seller gives you a lot of grief then take it up with Ebay right away.  Whatever you do, be sure to reflect it in your ebay feedback.

If using a nutted axle, it shouldn't be a safety issue but may take more effort to get the wheel on/off.


How to get the tyre back on to the rim easily?

I always use levers to get the tire off. Never to get it back on! You'll most likely pinch the tube if you do and have to start again.

The Schwalbe Marathon Plus tires are one of the most notoriously difficult tires to get on.
 This youtube video shows you how to do it without levers and without hurting your hands or getting blisters.

You only need two toe straps or a similar strap, to push the tire bead into the well of the rim on the opposite side to the last bit of tire you're trying to get back onto the rim. As you'll see from the video, just keep working the tire bead into the well of the rim on the opposite side and you'll get it on, no problem.

This was a saviour for me, since before that I'd get blisters and sore hands and it could take me an hour to change the Marathon Plus. Now it takes me a little over 5mins, with no blisters or sore hands.


Why does the glue in a puncture repair kit dry up so quickly?

In my experience:

You only need to apply a drop of glue a bit larger than a pea (about 7mm diameter) per patch;
Glue inside eventually dries. If you only have a puncture once a year, most probably the glue remaining from the last puncture would be dry "no matter what". Also, there is an expiration date of around two years, but I think it's two years if you didn't open it yet;
(IMPORTANT) When you attach the cover of the tube, BE SURE TO REMOVE ALL THE AIR INSIDE by pressing its bottom untill half a drop shows up in the opening, otherwise the glue will evaporate inside the very tube (happened to me a lot of times until I figured it out...).
These glues have a volatile nature. I wouldn't buy it in large amounts, but rather to buy new spare glue tubes (without the whole patch kit). The kind of patch I use also have this problem: the patches (a small roll I have to cut with a scissor) last much longer than the glue.

Well, hope it helps!


Best place to shop for parts in Canada (used parts)

Have a look at PinkBike's Buy/Sell pages.

This is a site for hard-core bikers, there are always parts of various qualities and conditions up for sale.


Shimano BR-MT520 brakes are hydraulic discs. The alignment can be adjusted by loosening the two mounting bolts. The bolts typically have Torx T25 size heads, so you need a basic T25 wrench at least. If your rear caliper is mounted between the seat and chain stays the bolts can be difficult to get to, so a L-shaped rather than a T-shaped wrench is necessary.

The basic short-cut technique for aligning the calipers to loosen the bolts so the caliper can move but is not loose, pull the brake lever hard, tighten the bolts. See this Park Tool page for more details on caliper alignment.

If your pads are rubbing periodically as the wheel spins, your rotors are probably warped. They can be straightened fairly easily. There are special tools for this but an adjustable wrench works reasonably well. See this Park Tool video.

Update:

I read through the BR-MT520 Dealer Manual and it seems the mounting bolts are in fact 5mm hex heads.


Will carbon fork make a huge difference when commuting?

Not much difference in ride from carbon to Cr-Mo.  Over 13km not much of a factor. The carbon is going to be lighter, more expensive, and less durable.  Same bike on a budget I would go Cr-Mo.  You list two different styles of bikes and a purebred road bike in a comment.  Pick the style of bike first.  I don't think purebred road bike is the right bike for that picture.  I personally think drop bars are more efficient and comfortable for paved commuting. And on a budget used might be more cost effective.


Options for servicing Speedplay Zero pedals

There are various rebuild kits available on the web, the site Excel Sports has various options, from replacing just the bowties if the main pedal is sound, or the entire pedal surface.

I have custom length spindles to accommodate foot splay, so I have used both a couple times to avoid the big outlay on replacement.


Why are bicycle tires incapable of maintaining pressure over time, while car tyres seem to have less of a problem?

A car tyre has much thicker rubber than a tubeless bike tyre, thicker still than a tube. The steel wires in the belts of a car tyre are impermeable to gas and occupy a significant fraction of the area of that layer.  So there is a material difference.  In both cases the rim can be regarded as impermeable, and the sidewall more permeable than the tread.

Car tyres, despite their much squarer cross-section, have a larger ratio of volume to surface area.  The volume determines the remaining pressure, while the surface area determines the leak rate.

Even taking that into account, car tyres don't really hold enough air for a year.  The fact that they may give acceptable handling for months on end has a lot to do with how forgiving driving a car can be compared to running on two wheels.  Try asking a motorcyclist (dimensions and construction close to car tyres) how often they top up the air.  But still, a few months should be OK on a car, though topping up once a month should improve your fuel consumption.

I don't run tubeless, so the following assumes tubes.  My tourer and hybrid, pumped to the max pressure, gives an acceptable ride for about 3 weeks on ~32mm tyres with cheap tubes.  That's starting from nearly 6 bar (85 psi) so over twice what most cars take.  My MTB doesn't get ridden much at the moment, but again with cheap tubes (though obviously fatter) can hold trail pressures for a little longer than that.  In practice I pump it up almost every use, because I tend to ride on road to the trails then let out some air.


In short: it depends.

Chainrings tend to be much more compatible across gear counts than anything else in the drivetrain. It amounts to "does the chain fit", and when you're talking 8/9 speed the chain width is the same anyway, so yes, that will work.

The real question is whether the bolt pattern is compatible between the two, because that's where the real variation is. But it's probably obvious - look at it, try it. Pull one chainring off and hold it next to the other bike. If the bolt holes line up you're good to go.

If you're asking whether you can swap the cranks with chainrings attached, that's harder to answer. The first question is whether the bottom brackets are compatible. There are several sorts these days, with the traditional square taper being superseded by larger diameter axles of various shapes. If those are the same, the next question is clearance between the chainrings and chainstay. The only reliable way to test that is trying it, for which you'll need the right tool(s) to pull the cranks off. With many modern bottom brackets that's as simple as undoing the bolts and pulling them off by hand, with square taper you need a special tool. When putting the other chainring on, watch that you're not pressing the chainring against the frame as you do the bolts up. Then make sure there's a few mm of clearance between frame and chainrings.


Windows Phone as a Bike Computer - What is the current State of the Art?

Having considered between unsing my android phone as a bike computer and buying dedicated computer, I noticed some points that could serve you.

Using cell phone:

You need a bike mount to be able to look at the data while you ride,
moreso for navigation, and they are somehow bulky, just like a cell phone compared to the dedicated bike gps you mention.

Cell phone battery will drain quicker, specially with sensors attached.
Usually, phone GPS is usually not as good, and for instance, I don't think I can connect to GLONASS satellites from my phone (Russian satellites for extra gps accuracy).
Bluetooth only allows for one sensor connected, so if you want to link a heart rate band, you could not link a cadence sensor.
If you want to connect sensors via Ant+ your phone need to be able to receive the signal, which is not the common thing, or buy an ant+ receiver

Usually phone apps give their best stuff on payed premium plans.
Phone apps usually take a good while deciding you stopped, which means a big time increase when measuring city commutes with all red lights etc. This can be avoided with speed sensor

Using dedicated bike computer

There are less expensive units that can connect to a phone to use it as their gps sensor, while the unit serves as smaller cockpit display with ability to plug in more sensors (basically HR, cadence and (more accurate) speedometer), but they won't show navigation maps.
Deciding between bike computers is already very complicated. The main difference is if you need navigating maps your options are less, and the better you need your navigation (i e you plan on using the gps unit on touring bike expeditions) the more clear it is that you need a big screen unit with plenty of battery time and good maps.
If you really like strava you may consider some devices that show strava segments live, but keep in mind this needs strava premium membership.
I found out something about gps recording: some units will record more data points of your traject than other. This could affect shorter strava segment times :P, but looks like it's not a big deal otherwise.
Some units have barometric meters on them, offering  more accurate elevation gain
Some units can display a great amount of data on the same screen
Some units have several training features that could be useful

I don't like and it seems it's not welcomed to give product recommendation, but since you mentioned it, I bought the gps unit you looked at. Still haven't used its follow track feature, but I bought it because of that. If you are not interested in maps, probably the competitor polar m450 is a better choice. For some reason I don't like the scheme that goes "no gps bike computer with connection to phone for gps" but it doesn't look like a really bad idea and it is way cheaper. Since I wanted a christmas gift i didnt check the cell phone bike mount, but I would have given it a try.

Also, keep in mind that for the price of a gps bike unit you probably can get a new cell phone with bluetooth and ant+, look that it has a good gps and battery life over camera quality or memory for instance, look that it is not very big and use it as a dedicated unit, but that would require research effort, and just getting a bike gps is more convenient.


Is there any loss of braking power associated with the noise? Does it feel that the brakes aren't working fast enough? Brakes do make a similar sound when water gets on the rotor for no loss of power.

From what you are describing and because you have realigned the caliper I would suggest your pads may have become contaminated or glazed and therefore not engaging properly. Check the pads for chips, hard spots or a glassy appearance (there may be a toe formed at the leading edge of the brake which is ok). Sand the top layer of the brake pad off until it is rough and dull again.

Also check the rotor for any greasiness (make sure your hands are clean and dry). Wipe the rotor with isopropyl alcohol or other non-residue type solvent to remove any decontamination.

Hopefully this will remove any scraping sound and take you back to the turkey gobble and squealing normally associated with Avid Elixirs.


It is likely the bike frame will not allow you to put 26 inch wheels on a 20 inch bike frame.  They simply will no fit.  Sorry.  At this point, try to sell it as is and get a 26 inch bike.


Increase your budget until you can afford second hand pedals with cup-and-cone bearings, then spend a few bucks servicing them.

DMR's V8 and V12 models are very popular and have been the same for years. The V12 typically has better seals and lighter materials than the V8, but both are serviceable.

Here's a guide on servicing the DMR V8:
http://steveukmtb.wordpress.com/dmr-v8-pedal-overhaul-cup-and-cone/

I got Wellgo's V8 clones via eBay for 7GBP delivered (about 10USD?). I don't know if they're the same internally but they might be an option if you cant get pre-loved DMRs.


Coaster brake: concave sprocket orientation

Your guess is right, it's a way of dialing chainline. Most commonly you use it in the more outboard position. It's easy to just measure front chainline and both rear chainline options and see which position is optimal.


Your chain skipping/dropping could be the result of a few things, so I'll lay them out briefly:

Your chain/freewheel could be worn out. If you recently replaced your chain, the worn out teeth of the freewheel won't mesh with the new chain and will cause skipping. Simply examining the profile of the freewheel teeth with pictures of a new one will give you a sense of whether this is a possibility. (Worn out teeth are sharper at the tops and, in serious wear, form little waves or shark-fins.)
It is possible that the chain installed is too narrow for the freewheel teeth (though it would be a very noticeable problem.) Muti-speed chains are typically 3/32" wide, while some single speed chains are 1/8" wide. Freewheels are manufactured in both widths. Where one can run a 1/8" chain on either width freewheel, a 3/32" chain will bind noticeably on a 1/8" freewheel.
The singulator installed on your bike may not be providing enough chain tension. The actual alignment of this component won't cause the chain to skip as it it on the slack side of the chain. This is an unlikely scenario but could occur if it has been in service for a while or damaged in some way. Replacing the spring will bring it back to original tension specs.
The most likely thing I can imagine is that your chain-line is off. Your chainring is set further out from the center-line of the bicycle than the freewheel is, causing it to catch on the freewheel teeth and be thrown off. If the bicycle is a homebrewed single-speed, chances are you reused the original crank and bottom bracket spindle that were designed for a multi-speed bike. If this is a store-bought bike, it wasn't set up properly. Here is Sheldon Brown's article explaining the chain-line and how it is adjusted. In a nutshell, you will use different BB spindle lengths, BB spacers, and/or chainring spacers to line up the chainring with the freewheel. This can be done easily if you have the right tools and some patience. Here is a SE question relating to adjusting chainlines. Good luck!


9-Speed Ultegra (6500) with Mountainbike Derailleur

All nine speed Shimano shifters index with all pre-ten-speed Shimano MTB derailleurs.
All nine speed long cage MTB derailleurs with long (SGS) cages will have total capacity sufficient to run any cassette they can clear with a double in front.
36t large cog cassettes came out late in 9-speed mountain's life. Only a very few Shimano 9 MTB derailleurs are rated to clear a 36t for their largest cog spec. Most do 34 and a few only 32.
The SRAM you have is a 1:1 and has no compatibility with the shifter.


I've almost done this, and its not "easy" but it should be possible.

However a non-stop 100 km is much harder than simply doing 100 km.  Try working up do it.  I don't know what your current distance is for a "big ride"  but start with 25 km non-stop, then work up to 50, 75, and then 100 km.

Leave early in the morning on your big rides - it seems to help the distance go by easier.  Having twilight close in is a bad feeling.

Also, its cooler in the morning and you can stretch your water further.  Pre-hydrate, carry food, eat the food (!), and pace yourself over the distance.

Weather, specifically winds could be a big difference between a fun ride and a torture.  Consider reading your local meteorological service predictions that morning, and try to pick a route that should have a tailwind out, and a tailwind back.  This

If you can go with a group, that will help your speed, but increases the chance of someone having a reason to stop.   You could lay a challenge, something like *"Ride from Zeros to Little River and back to Zeros without putting a foot on the ground and I'll buy coffee for everyone who does it."

Climbs will cause you problems, and a route that is significantly more downhill will feel like cheating.  An Out-And-Back will make rises equal descents.

I'd also draw a distinction between stopping because you need to and stopping because you have to.  Red traffic lights means you have to stop,  You might be able to drift up to the stop line at minimum speed and stay in the saddle till the light goes green, but that's chancy and duplicated for each set of lights you pass.   If there's an accident, you stop and help and forget the challenge.

Personal stories - I've done a 100 km ride called Le Race.
https://www.strava.com/activities/520613679/analysis
It has over 2km of climbs too, and while the first half was great, the last half turned into an endurance ride instead of a race.  I had one stop at a red light before leaving town (despite roads being "closed") and one long stop with a puncture.  After halfway I stopped at every water station because I went through 12 full bottles of water, but was only carrying 2.

Separately, I did a road ride by myself for 146 km that was a "great loop" around Christchurch, Rangiora, Oxford, and back via the Waimakarerei Gorge.
https://www.strava.com/activities/694129685/analysis
I had one big stop in the middle of that at my Nana's house at about 75 km.

The takeaway is, can you sit on your bike for 5-6 hours solid ?


Race organizers: how much does it cost to put on a stage race?

If that event truly folded because of financial pressure one could assume the total cost of the stage race approached the revenue generated by the race which was likely between $65,000 and $80,000 based off the pre-registration numbers shown for the race on BikeReg.

With that said, I can roughly estimate some fees based off the USAC fee schedule, my personal experience with races my team produces and conversations I've had with other Race Directors:

$1500 - Volunteer food/drinks (~$10 per volunteer. Estimate this event needs 125-150 volunteers based on size of circuit and road race courses)
$225 - USAC Permits (Class D event, $75 per day)
$3359 - USAC Per Day Per Racer Insurance ($3.60 per racer per day)
$300 - USAC Chief Ref ($100 per day)
$240 - USAC Chief Judge ($80 per day)
$420 - Additional USAC Non-Moto Refs/Judges ($70 per day each)
$80 - USAC Chief Timer (Time trial. $80 per day)
$1260 - USAC Moto Refs ($70 per day per each)
$875 - USAC Officals Per Diem ($35 per day requiring overnight)
$2500 - USAC Officals Hotel Expenses (will depend on local rates, assumes 25 nights at $100 each)
$???? - USAC Offical Travel Cost ($.046 per mile)
$550 - USAC Additional 4mm event liability Insurance
$950 - USAC Non-Owned/Hired Motorcycle Insurance ($100 each named driver for first 5, $50 each after. Need 14 refs to cover stage 3 road race)
$600 - USAC Non-Owned/Hired Automobile Insurance ($30 each named driver, need 6 for stage 2 circuit race, 14 for stage 3 road race. Assume no overlap of drivers between day)
USAC Offical Travel Cost ($.046 per mile)
$1890 - Leader Jerseys (Voler Full Custom $63 each)
$1500 - Neutral Support (Sram $500 per day for 1/2/3 field, cost might actually have gone up)
$9320 - Prize List
$200 - Bib Numbers
$350 - Timing Chips (passive, $0.70 each)
$3300 - Timing Services ($3 per racer per day, $1,100 minimum per day. Note: Timing for the time trial may be higher.)
$1800 - Portable Toilets ($100 per day each. 4, 6, 6 needed)
$933 - Local Association Fees (Varies for different LA's but estimate at $1.00 per racer per day)

The following items will also need to be considered but could vary greatly based local:

Trophies
Other Hotel costs (Think Key race personnel/volunteers)
Onsite Medics (2 each day)
Onsite Ambulance (if required)
USAC Fees for any additional named parties on the insurance certificate
USAC Fees for any pre-race meetings with Officials
Fencing
Police Support
Generators
Tents/Tables/Chairs
City/County/State Permits
Traffic Saftey Plan
Announcer
Sound System Rental
Misc Office Supplies
Volunteer Safety Gear
Water/Sports Drink for Participants
Vendor Permits
Trash Removal
Traffic Cones/Saftey Tape
Signage
Street Sweeping
Road Repairs
Venue Rental fees
Fuel costs for pace cars/wheel vans

It is worth noting the way a stage race is composed can dramatically change the cost of putting on the event. For instance the Tour of the Catskills is a 3 day event but only has 3 stages. If the race was held as a 2 day event a number of costs such as those for officials, permits, medical support, neutral support etc. would be lower.

Additionally the sheer number of race categories and the fact all of the Stage 3 races are on the road at the same time increases the cost quite a bit. In stage 3 you have 7 separate fields racing at the same time which means you need to find and pay insurance for 14 moto refs, 7 pace cars, 7 wheel vans.... A more typical Amateur 2 day, 3 stage race composed of a road race, time trial and criterium or very short circuit race would be much less costly to produce than the Tour of the Catskills.

One thing not included above is an estimate of any in-kind sponsorship support received. At the very least you would want to make sure you have enough sponsors to provide prizes for any of the fields that are receiving merchandise prizes instead of cash prizes. Ideally you would want to find in-kind sponsors cover as many of the misc. services required by the race as possible. This can have a dramatic effect on the profitability of a race.


Suggestions for protecting jeans from saddle clamp bolt

I would suggest cutting off the extra threads. If you have access to a Dremel or similar tool it wouldn't be too difficult. Doing it with a hacksaw could be a real pain. Alternatively you could check your local hardware store for acorn nuts. The smooth ends should cover the threads which is likely doing the most of the damage.


The info I have gathered on line suggests your bike is equipped with a 3x7 speed drive train. If that is the case the most likely axle is a 9mmx135mm QR (quick-release). You have apparently discovered the weak link in 7 speed freewheel drivelines. The issue with using a freewheel set-up is the drive side axle bearing is about 1.5 inches inboard from the edge of the frame. Unless you modify your riding style the axle is likely to break again. You can try to locate  a used 27.5 wheel with  an 8 speed cassette. Cassette wheels use a freehub not a freewheel. Freehub wheels mount both the bearings at the ends of the axle. You can have the rear derailleur adjusted to use only 7 of the rear gears. This will save the expense of buying an 8 speed shifter.


Do helmets really lose their quality with time even if kept in package?

A lot will depend on the construction of the helmet. For example the basic material in the helmet will be some sort of sponge or foam which relies on its texture to absorb sudden impacts; does this degrade over time? For example, a loaf of bread gets its texture from the tiny air bubbles formed while rising and proving, but if left to prove too long, the structure collapses, or, once baked, the bread will harden and not be as flexible.

So it might be with helmet foam; at least, that's the concern, in particular when subjected to sustained UV/sun light. It's certainly not been a concern that manufacturers have been quick to dispel.

But there is another side to this question, not just whether you should not buy an older helmet because it has lost its ability to do its job? Have the helmet construction methods moved on since that helmet was made, simply, are newer helmets better? Are they lighter, stronger, more absorbent, better value, more adjustable?

Many reputable organisations, e.g. the Bicycle Helmet Safety Institute, say not to worry

  Most manufacturers now recommend that helmets be replaced after five years, but some of that may be just marketing. (Bell now recommends every three years, which seems to us too short. They base it partially on updating your helmet technology, but they have not been improving their helmets that much over three year periods, and we consider some of their helmets since the late 1990's to be a step backwards, so we would take that with a grain of salt.) Deterioration depends on usage, care, and abuse. But if you ride thousands of miles every year, five years may be a realistic estimate of helmet life. And helmets have actually been improving enough over time to make it a reasonable bet that you can find a better one than you did five years ago. It may fit better, look better, and in some cases may even be more protective.

The Snell foundation concurs:

  Hair oils, body fluids and cosmetics, as well as normal "wear and tear" all contribute to helmet degradation.

Although I would hesitate to buy a helmet which can't stand up to sweat, this suggests that it is use that affects the longevity of the item, not its storage.

I'm not a scientist in this area, but while there might be evolutionary reasons in the helmet's construction to merit buying newer ones, just being stored for a few years probably won't be reason enough.

But as I asked in an answer to a related question, why are you planning on wearing it? If you're looking for a cheap helmet because you don't really want to wear it, then an old one will be fine, but if you're genuinely concerned for your safety and you really want something to do the best job, then should you be quibbling over the few dollars/pounds/{currency units} difference?


Preventing use of low gears while training

You can probably turn the limit screw far enough in to prevent usage of at least the largest cog. Maybe even the second largest cog.

You could also stay on the larger chainring. Depending on your specific cassette and chainrings it’s roughly equal to not using your three largest cogs.

All that being said, in the end cycling is about power output. Using hard gears doesn’t automatically make you faster. Power is force (or more precisely torque) multiplied with rotational speed. Easier gears may allow you to pedal faster, resulting in the same power output over – possibly – a longer duration.


How do I tune up the shifters/derailleurs on my mountain bike?

You said to explain it as if to a child so here it goes.
Basic Shifter/Derailleur concepts: The derailleur spring is always pulling to the smaller ring(s). Assuming your bike has Trigger shifters since you said it was a MTB, the big thumb lever will push the derailleur to the bigger ring(s). This is true for both front and rear (left and right respectively). The trigger is basically a "catch release", letting the spring pull the derailleur to the next smaller ring.
Setting the Rear Derailleur (RD):
Preferably with the bike in a stand, but can be done upside down, get the RD into the smallest ring (pull trigger until it stops clicking).
Start turning the pedal with your one hand and push the thumb lever to shift to the next bigger ring. If it shifts smoothly and quickly, push the lever again, etc.
If, after you shift, the chain doesn't bump to the next cog, find a barrel adjuster and turn it as if you were loosening it (CCW) while still turning the pedals. You are, in essence, lengthening the cable and pulling the RD toward the bigger cog (inboard).
Once you get to the biggest cog, pull the trigger so that it starts to shift toward the smaller cogs.  If it doesn't drop down, you'll have to turn the barrel adjuster as if you were tightening it (Clockwise) effectively shortening the cable and letting the spring pull it farther outboard.
Front Derailleur (FD):
The process is similar to the RD. Shift so that it's in the smallest ring (pull the trigger).  Once there, inspect the cable.  Note how much slack there is. If the cable has a lot of slack (no tension), try to find the barrel adjuster and turn it CCW (loosen/lengthen) until there's only a very slight amount of tension. If the cable it still taut, I like to shorten the cable (turn Clockwise) until there's very little tension.
From there, turn the pedals with one hand and push the thumb lever on the left shifter.  If it goes to the next ring, sweet.  If it's having difficulty, I stop pedaling, turn the barrel adjuster CCW, then shift back to the small ring (pull the trigger), then start pedaling and push the thumb lever again. Repeat until it shifts cleanly.
Adjusting the limiters:
Both RD and FD have limiter screws that limit (obviously) the boundaries of the the derailleurs.  They will most likely be Phillips head.

They keep the RD from going into the spokes or dropping the chain between the cassette and the wheel. On the FD, they keep the chain from dropping in off the small ring or out off the big ring.
FD: Shift to your hardest gears in front (biggest ring) and back (smallest ring). Many derailleurs will label the screws with "High" or "H" and "Low" or "L". High = Hardest/Outboard, Low = Easiest/Inboard. The way the gears are now, you'll be adjusting the "H" screws.  If they aren't labeled, you'll have to look and see which screw is actually hitting, or nearest to hitting, another part of the derailleur. Adjust the FD so that the outside of the FD is about 1mm from the chain or as close as you can get it without rubbing. (The latter for cheaper cranksets that develop wobbles in the chainrings).  Adjust the RD so that the cage and pulleys are parallel with the smallest cog.
Now shift so that the RD is in the Biggest Ring and the FD is in the smallest. This is your easiest gear or fully inboard.  Now using the other screw ("L"), again, adjust the FD so that there's about 1mm space between the derailleur and the chain or until there's no rubbing.  Adjust the RD so that if you pull the cable with your hand it moves no more than 1/2 the width of the chain.  Just enough so that it can shift to the big cog easily and stay there effectively.
If there are still issues, there could be other things at play. You might have to replace housing or cables.  Maybe your RD hanger is bent.  Maybe your FD is askew

Hope that helps.


Is stem cap redundant after tightening stem bolts?

Yes this is correct. Once the stem bolts are tight, they hold the system together. The top cap can be loosened without releasing the preload. You could try it out and you should find that the stem remains fixed and no play will develop.
You'll still need the top cap next time you want to preload the headset, so perhaps not redundant... maybe furloughed is a better word ;)


That looks a lot like the bikes in some bike-sharing programs (take a look at this one, from Stockholm City Bikes). The two "prongs" at the end of the front "basket" would be used to lock the bike in place at one of the stations. The panels in the back are often used for advertising.


What kind of upgrades to a BMC AC02 hybrid?

The best upgrades would be a set of clipless pedals, compatible shoes, and some nice cycling clothes and helmet. And maybe a good set of lights. You can carry all these over to your next bike.

Another nice upgrade is a bike repair stand and a basic bike repair toolkit.

Finally, a good GPS bike computer or GPS watch will set you back a few hundred dollars.

I think you get the idea. There are no "upgrades" to an essentially new bike itself that need to be made. Only buy things that will encourage you to cycle more (Strava premium membership!) or that you can take with you to the next bike.


Dimensions of Mudguard suitable for Fuji Absolute 1.9D 700mm or26.5 inch tyre

I'm going to try and answer generically.  You can apply this to your own bike.

A mudguard/fender has one main task, to stop water and muck from transferring from the tyre/tire to the bike and the rider.

ROAD

So, the best-performing mudguards you can buy will be "full" ones, something like this:

Points to note:

guards are pretty close to the outside of the tyre.
front edge of rear guard goes right down to the bottom bracket.  This protects a lot of the bike's transmission
rear edge of rear guard trails behind the whole bike - its a good place for mounting lights and reflectors.  Also protects other cyclists behind you from the taste of road water.
front guard is only a quarter circle, but there's nothing in front of you to protect.
front guard also allows the suspension to work as normal.
neither guard messes with the function and performance of the brakes, whatever is on the bike.
both guards are supported by two additional struts, as well as the brake mount point and the rear's chainstay mount.  More support means less rattling.

Materials - some people prefer plastics, some chromoplastics (plastics that look like metal) and there's also steel and aluminium/aluminum options.  Probably have a hard time finding carbon fibre/fiber ones, but they may exist.

MTB

These ones are primarily for off road or muddy use.  They flap around a bit more, weigh less, and catch a lot more air.  They also tend to snap off in any form of accident, which is not altogether bad but they're also not overly durable.  Almost always made of plastic, these MTB ones don't have a lot of support other than one bolt or clamp.

MTB ones may not provide a lot of protection for the drive chain - this picture has an additional one down low on the rear wheel, but in really serious mud this could clagg up with grass and pog.

Significant plus is that these are a lot cheaper than full guards.

Emergency

This is an Ass-Saver (tm) (etc)   There are many emergency guards, but this one has the cheesy name.
They clip into the saddle rails and jutt out the back.  That's all.

They're short but on a road bike that's okay.  Downside is that they're so far from the wheel that roadspray still flies up and hits me in the back of the thighs anyway.  These also do nothing to protect the bike or the components of brakes or transmission.  For a tenner they're overpriced.

I've also been known to slip a medium flattened cardboard box between my back-side and the saddle.  It worked.  This chap has wedged cardboard in the back seat stays.

If you have a rear carrier, you can put a layer of cardboard or reuse something made of plastic.  This is what I have on my wetbike, and it works well enough, no photo sorry.


Ease of Continental road wire bead tire mounting and dismounting

In my experience, Continental-brand tyres are neither difficult nor easy to fit when new.  They certainly require leverage tools like tyre levers or similar, but they're much easier than a Schwalbe Marathon.

I've fitted both GP4000 and Gatorshell tyres in the last year or so.

Personally I prefer kevlar bead tyres now over wire bead for weight, ease of fitting, and easier postage.


No. Can not, must not. Fluid type mismatches in either direction can make seals and other non-metal parts degrade, swell, and/or fail. Mineral oil, being the less caustic and reactive one, will generally do it more gradually when this mistake does get made, but it still does it or at least can.


You can get a close approximation if you have access to a trainer. Install the bike in the trainer with the fork and headset installed. Using a front wheel riser block will make the fit closer to your actual riding position. You can now install the stem at any height you like. When you find something close measure the gap between the bottom of the stem and the top of the headset. I would get a variety set. Most come with a 2mm,5mm,10mm and 20mm. I just did this myself and I got an extra 20mm that I installed above the stem.This allows for some flexibility later. The spacers can be shifted for a different fit for different riders or resale. It is easier to cut the steerer later than try to make it longer.


Why rear derailer has limit on front chainring difference?

It is not directly connected to the difference between the front chainrings.
Instead, a Rear Derailleur will have a "capacity" which is the total amount of chain it can take up before bottoming out.
The RD also has a value for the small cog (often 11 tooth) and either a maximum-sized cog, or some of the new specs give a maximum and a minimum tooth count for the big cog.
For example, that specs page linked in your question says

Low sprocket_Max. 36T
Low sprocket_Min. 32T
Top sprocket_Max and Min. 11T
Total capacity    43T
Max. front difference 22T

The cassette can "eat up" between 21 and 25 links, and the total capacity of the RD is 43T.
43T less the 21T consumed by the smallest allowed big-cog is 22 T
So your bike might have a 48T big chainring, and the smallest chainring is 26T.  Any middle chainring has to be between those.
You could have a 53 tooth big chainring, but your smallest could be no smaller than 31 tooth.
summary  The chainring difference is easier to understand for consumers, its just processed the other values.

Putting this another way: Imagine your hardest gear is 48:11 and easiest gearing is 26:32.  The rear mech will be almost flat, pointing forward and the chain through will be near straight.
Changing chainrings releases ~22 links of chain, which adds to slack.  Your rear mech has to fold up and take up ~22 links, now its in 26:11.
Then changing up the cassette uses 32-11 = 21 links of chain.  Thats the lower boundry.  If you had a 36T max on the rear, it would use up 36-11 = 25 links of chain.  Those two values of 21 and 25 straddle the 22 tooth number quoted in the spec.
Note that Shimano's specs are notoriously conservative too, you can almost always add 2 teeth to any maximum and still have perfectly good performance.

If you had far more difference between your chainrings than 22T, it wouldn't shift very well.  16T is quoted as a reasonable maximum between adjacent chainrings, and 22T would imply a triple crankset with a third chainring.
So if you exceeded the front difference of 22T with (say) 30T, then moving from big chainring to small would release ~30 links of chain, the extra 8 links has to go somewhere.  This might let the derailleur rub the chain back on itself in a small-small gearing, or would not put enough tension on the chain resulting in sloppyness and possibly chain slip.
Example: This chain is too long, and is rubbing on itself.  The gear is a small:small combo so there is the most "spare" chain outside of the chainrings/cassette.
  From Is my chain too long?


Product recommendations are off-topic on this site because they are geography-specific, taste-specific and quickly go out of date. However, there are several questions in your question that can be answered (and as such, they should have been submitted as individual questions to the web site in the first place). Let me address a few of them.

The need is reliability, longevity and cheap maintenance.

In these terms, nothing beats a single speed bike actually. There are fewer details to wear and to damage on it. A bike with internal gear hub comes next.

I'm not sure, but the far I know, they just get the wheel coming to a rather sudden stop,

Brakes in general are meant to stop a bicycle, and the faster they can do it, the better. It is up to their operator to control them properly; after all, you can fall off your bike even without brakes, being perfectly still. Any type of brake requires proper rider technique. There are a lot of materials about proper braking on the Net.

and are also harder and more expensive to maintain. Aren't they?

No, not really. Mechanical disc brakes are as complex in maintenance as mechanical rims brakes. Hydraulic disc brakes are even simpler in everyday's use, until you need to bleed them, and then it becomes somewhat tricky.

What I also want to ask is, say, I get the Munich itself, is it a good idea to swap components before I begin?

No, it is not a good application of your budget. New aftermarket components are more expensive to get than if they came with a complete bike (bike manufacturers get a huge discount on bulk purchases, compared to us mere mortals)

Different websites told me that TX series is better than TZ series, hence the question.

Both of these series are pretty much budget components, to be honest. It is very unlikely you will feel a difference between then. Instead, learn how to tune your existing derailleurs in order to get the best value out of them.

I'm not sure if I should be buying online either

Going with a second hand higher-tier bicycle is also an option; it may be more comfortable to use because of the quality of frame/components to start with. Unless you are 100% sure about the size of a bike you need, you should not buy online simply because you might get a too big or too small a frame.

I've read various reviews that talk about how much more they've had to spend because of multiple problems with the bike (broken rims, problems with the cassette, derailleur, etc).

These problems are not specific to the online/offline markets. It is up to the people who assembled the bicycle in the first place, and the customer service they provide. Make sure you buy at a reputable place in the first place, regardless of whether it is on the Net or offline.

I'm also unsure whether triple chain rings are a good idea and would like to know if I should swap them out for something else or if I should just get a bike that's got a single chainring.

Triple chainrings are usable; people have used such setups for decades. At the budget limit you have, it is unlikely you will find any new bike with 1× setup; a used bike, quite possible. 1× setups have many advantages: weight, simplicity and reliability, fewer components related to shifting. Their disadvantages are: price of new setup and replacement parts, single point of failure upfront, "sexier" look and as such proneness to being stolen.


Switching a 11 speed cassette+wheel with a 8 speed freewheel+wheel. Any compatibility issues?

No sorry, this is not practical.  Freewheels mostly stopped at 7 speed, and 8 speed was rare because of excess unsupported axle causing bent axles due to leverage.

Your suggested plan would require fitting 8 speed shifters and an 8 speed rear mech.  That's too much faffing about when you want to swap wheels.

Instead, you could find an 11 speed hub with the same spoke count, and buy an 11 speed cassette.  With luck the donor wheel's spokes will suit, and you can reuse the 8 speed wheel's rim in a new wheel.

The front wheel should be a direct swap, other than checking brake pad alignment.


Compression ring not holding top of fork in place

There's often a very thin intermediary washer/spacer piece that goes between the compression ring and the top plate. Some headsets have it and some don't, but on one that was intended to have it, leaving it out would cause the exact problem you're talking about, as the top plate would bottom out on the bearing cup or headtube before it makes contact with the compression ring.


Depends on how extreme the wobble is.  It takes very little lack of trueness to cause rim brakes to drag, but in a pinch you can usually disconnect the cable or some such and still manage (assuming the brakes on the other wheel are OK).

After that, the wobble of wheel is distracting and will make the bike unpleasant and tiring to ride at high speed.  Also, of course, it impacts the stability of the bike, making falls more likely.

If the wobble gets worse, the wheel can begin to rub against the fork or stays, and it gets unrideable.

One does need to be wary if, say, a single spoke is broken, causing wobble.  This situation puts additional stress on other spokes, making a second failure more likely, and a second failed spoke in the wrong place could cause the wheel to become suddenly quite "loopy", resulting in a crash.


Will shimano 10 speed triple shifter work with compact chainset?

While Shimano does have one shifter (2010 ST-5603 105) which will work with either triple or double drive trains, no 10 speed shifter works with a 9 speed cassette, at all.

There are cam adjusters which claim to correct cable pull and allow you to use mismatched equipment, but how well they work is open to debate.

You should maintain as close to matching specs as possible.  All 10 speed or all 9 speed equipment is pretty much mandatory.

Mixing brands is likely to degrade performance to some degree, although it will work, usually.

Bottom line is, if you need to ask the question, you don't have the necessary experience to make sure that everything comes out ok at the end.

On the other hand, you'll learn a lot if you try it, and if you can afford to experiment, it could be fun to try to make it happen.  Be prepared to buy everything 2 or 3 times, if you do try it.

Hope that helps.


I'm no racer so I'm probably speaking from a very different point of view than you were interested in. I have used Sram 9-speed chains for years on my touring/commuting bicycles. I have used the 971, 981, and 991 and haven't been able to see any difference in performance or longevity, either. With my wet-weather commuting here in the Seattle area where it's pretty nearly wet every day from October through March, and then there's plenty of rain in April and May, too, I have been able to wear out chains and cassettes very quickly.

I'm not a mountain biker--or at least not an avid one--so I have never really hammered the chains in the muck but I have never had one of their chains break. I've just managed to wear them out over time.

I do greatly appreciate the master link because it makes it easy to take the chain off the bike and put it back on again. Before I switched to a bike with a Rohloff internally geared hub for my commuting, I would keep two chains in rotation on my bike and take one off, soak it in cleaner, and let it dry while I put the other clean chain on my bike.


What are the most effective exercises to improve stamina and speed on my cycle to/from work?

There's nothing bad about maintaining a steady pace but at some point you'll want to increase that pace. For a while you will be able to improve significantly by just informally "trying harder" and getting more skilled with the bike. After a while, however, you will plateau and it will seem like it is impossible to get much faster and you'll wonder how people on mapmyride (for example) can do the same route at unbelievable average speeds.

Of course it is possible to get much faster! And the most effective way to do it is with some type of regular interval training. This same concept applies to all endurance sports. The idea is that you have to push your exertion to at or above your lactate threshold to stimulate improvement. It is the aerobic analogy to lifting weights.

I am not going to attempt to lay out a program, but roughly it is going to be a series of efforts that last a couple of minutes with a few minutes of rest inbetween. During those intervals you really have to max out to get the benefit of the workout. A "real" interval workout is HARD and draining. It is not something that you'll want to do everyday.

Alternatively, just riding with fast group will do the same (albeit in a longer time) as guys tend to naturally compete and "put the hammer down" at every opportunity.