Hot answers tagged

24

It's hard to say exactly what the cause is, but I see two main possibilities: Mechanical causes Brake pads. If the pads are very close to the rotor when at rest, and have minimal motion to close on the rotor then that may be enough to wedge them. Try inspecting the brake pads and if worn, replace them. Brake pads are consumable. Thin brake pad ...


16

Depends on how "little" the accident was. First double-check that the handlebar really is "square" to the fork, and not slightly cocked one direction or the other. (Though this problem shouldn't cause the wheel to turn when you let go.) Next, oddly enough, do the same check with your seat. If the seat is slightly angled to one side or the other then it ...


13

I think you need to separate operator error from optimal mechanical functioning. Mechanical advantage By your own anecdotal evidence you have demonstrated how powerful front brakes can be. In short we have front brakes because they are the most powerful brake. When a bike (or any vehicle) decelerates weight is shifted to the front wheel. Because ...


11

A front derailer is a bit more complicated than it looks, and can be quite complex to adjust if you're starting from zero -- just having installed the unit. There are five (and a half) adjustments -- Height, sliding up and down the seat tube. Rotation around the seat tube. Low limit High limit Cable tightness Generally height is such that the derailer, ...


10

Most likely cause if the disc and pads are contaminated. What did you wash it with? Many cleaners leave a residue. Worst case the pads need replacing. The discs should be well cleaned before installing new pads - Use a solvent such as brake cleaner, methylated spirits or Isoprop alcohol, and rub the discs to be certain no contamination is left on them. ...


10

Park Tool list a number of common sizes. 3/8 inch x 24 tpi Some solid axle bikes, including coaster brake 3/8 inch x 26 tpi Solid rear axle 10mm x 1mm Most quick release rear axles 10mm x 26 tpi Rear axle, quick release, Campganolo® Note that the difference between 24 and 26 tpi is small and can be subtle, meaning that if you're using a spanner ...


10

Small children usually do not have a grip strong enough to brake effectively with brake levers on the handle bars. Neither do they have enough coordination to modulate brakes. This means if they were able to brake the front wheel effectively they would indeed be at risk to go over the bars. Typically, children's bikes have coaster brakes. These allow to ...


10

Don't - its dangerous ( Majority of braking force comes from front brakes) and in many countries illegal to ride on the road without 2 operational brakes. Likely you are using too much force and not enough control. You need to learn to feather brakes rather than jam them on, while shifting the weight back and lower. Another possibility is you are using ...


9

If you have quick-release or bolt-up front axle that is not properly tightened, then going over a bump could cause it to come out of the fork dropouts. Normally dropouts are equipped with lawyer tabs to prevent this, but they aren't 100% effective or your bike may not even have them. Once it drops out of the dropout, the fork would then no longer be ...


9

It is unusual to see a hydraulic brake described as on/off, as they are usually well known for their modulation. However I have had an experience of this before with a friends bike. He was regularly locking up the rear wheel, and initially I put it down to inexperience as a new rider - until I rode the bike myself and found the brake to be extremely '...


8

Proviso - my advise presumes you are not looking at forking out $2K or more for a bike, and probably significantly less. At a high price point I might suggest suspension. I also presume the gravel section is well maintained with average (pea - grape) size gravel (Where I ride, we sometime use logging roads, the "gravel" is stones about 2"-3" across.), and ...


8

The fork is "right" if it has the right "sag", that is, if it lowers a bit when you get on the bike. The right sag is no less than 10%, no more than 25% of total travel, for a regular bike (non-downhill, non-special-purpose); Basically three "areas" must be addressed on maintenance: Cleaning the inside, for removal of old oil/grease, water, mud, grime, rust,...


8

What I worry about mainly is the horizontal alignment of the wheels and brakes (V brakes or disks). In my experience just pressing fork down on the wheels will then "auto fit" which creates an horizontally accurate alignment. I press from the handlebars vertically to the ground and the wheel keeps an horizontal alignment with the brakes (accurately set). ...


8

So what do we need front brakes for? We need them for maximum braking efficiency and better control of the bike. Your question is flawed in the sense that it only has anecdotes from unskilled riders. Let's see some similar examples of equipment misuse: why do we have a rear brakes? They are not efficient and last time a friend of mine used it, the bike ...


8

There are more factors than just the front brake that contribute to the flipping accident. I myself got into the accident once. It happens so fast that you never have time to lean your body backwards and provide more tractions for the rear wheel like other have stated. I should list some of the factors that contribute to the 'flipping'-style accidents: ...


8

Put the 3/16" bearings back in, even if you have to buy some fresh ones. Your quarter-inch bearings are not sitting in the bearing raceway right which is causing the too tight/loose problem. They will never sit right, and if you do ride on them the bearings will run on the wrong parts of the cup and cone races. This will lead to early failure of the cup ...


7

We have front brakes in order to stop. In an emergency stop there is hardly any weight on the rear tire, and the rear wheel has very little traction. In each of these cases, the bike would not have stopped where it did, and there are certainly situations where rolling further would be more dangerous. There is a proper technique which is get back and low, ...


7

This is inexplicable and we're missing some details. Any modern bike tyre will be 20mm wide as a bare minimum. Your electric scooter appears to have approximately 2" or 50mm tyres from the photos. As such a 5 mm bump will be no more than a quarter of the tyre - its not even going to snake-bite at normal pressures. At 10% the height of the scooter's tyre ...


7

The front wheel itself (for rim brakes) should be symmetric and can be installed both ways, unless you can find direction marks printed directly on its rim. The tires, however, can have recommended direction printed on them, which you should follow. For fully slick tires both directions are equivalent. For tires with tiny tread it is not as important as it ...


6

Yes - one or two torque arms will help. Otherwise all the impulse is being send through your dropouts, which will be steel and will flex. This undoes the wheel nuts over time. This also fretts out the dropouts whih will cost you a new fork. Do you have anti-rotation washers in the fork dropouts too? Even my 250W motor needed them. More info: From ...


6

Its impossible to answer this for you. The LBS who fixed the wheel is in the best position to give the advise you seek. My motto here would be 'If in doubt, throw it out'. If it was the rear wheel my answer might be different, but front wheel failure tend to be more catastrophic and most often occurs when you load the front wheel - think what happens if ...


6

The lever pointed down is in the closed position and is how the manufacturer intended for the brakes to be used. The brake pad clearance should be set in this position. If the brake cable is routed correctly and the lever fully closed (and not damaged), tension on the brake cable will further lock the mechanism in place as it is on a slight angle causing the ...


6

Can anybody suggest where to get these small plastic parts? Buy a new shifter. Shimano does not sell replacement shifter parts, so the only way to get parts is to buy another shifter. And it's a lot easier to replace the old broken shifter with a new one than it is to take apart the new one, remove the needed parts, and reassemble the old shifter with the ...


6

Found out those "clamps" are called conduit hangers: https://www.homedepot.com/p/2-ACC-Conduit-Hanger-67820/202077114


6

To cold set a regular fork by 30+ mm would no doubt weaken it far too much to use. The better starting point would be something like a 135 mm fat bike fork, common sizes are also listed in the Sheldon brown table you linked. Notice however, that three of the four pictures you found feature extensive modifications to strengthen the fork or supporting frame ...


6

You can do it with files. The chrome does make the surface harder but it's not a big deal. This is usually seen when the fork was originally slotted to take a 5/16" axle. I'm not a Raleigh historian but I'd be a little surprised were that the case on a Grand Prix. It's also possible that it's a fork that fits a 9mm front axle very tightly, and you're trying ...


5

Rear derailleurs don't care whats up in front and vice versa. Rear derailleurs don't care about the number of cogs in the back, but front derailleurs care about the number of chain rings (you can get a triple derailleur to play nice with a double chainring, but you should probably get the right part to begin with). Speeds are mostly marketing though, as ...


5

Wow what a horrible guide. Tightening the gear cable while in the highest front gear is very tough and will only hurt your fingers. I recommend putting the front dérailleur into the lowest gear and tightening it that way. This is much easier! As for your specific problem, in all my experience you can never not get 'rubbing' (if by rubbing you mean the ...


5

with a bigger chainring you may simply need to install the front mech higher up the seat tube.. The outer part of the 'cage', if correctly positioned should be just a couple of millimetres above the biggest chainring when you change up.. Not sure this answers your question but i hope so...!


5

There are two types of caliper brakes, the side-pull and the center-pull. You have the center-pull but are used to side-pulls. Side-Pull You're used to the side-pull. There, the cable comes to one side and squeezes the arms together. Because it's not symmetrical, it uses the pressure of the brake shoes when full-squeezed to center itself around the single ...


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