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 ...


21

The 'noodle' (the curved silver tube the brake cable passes through) has slipped through the holder on the right-hand (in your picture) brake caliper. The noodle is designed to come out of the holder to spread the calipers to enable the wheel to be taken out. The proper configuration looks like this: Squeeze the calipers together and free the noodle from ...


21

The return spring on the right hand caliper (from the point of view of sitting on the bike) has come out of its stop in the caliper. The spring in the left hand caliper is pulling both calipers to the left. You can see the return spring sticking horizontally out of the right hand caliper. It looks like about 10cm of stiff wire. The spring wire should be on ...


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 ...


14

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 ...


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

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,...


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

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 ...


8

Here's an annotated rotated version of your photo: To get the wheel in: Pull the RUBBER BOOT to the right, slide it along the INNER CABLE toward the PINCH BOLT Squeeze the BRAKE ARMS together at the top. This allows the NOODLE to move to the left, permitting the YOKE to swing away from the NOODLE. When the bike is upside down like yours, it may need a ...


8

A further thing to watch out for when following Argenti's (correct) advice: Check the end of the noodle holder very carefully. I've seen some old, cheap V brakes in which this was too soft and opened up allowing the noodle to slip through in a similar way to the photos in the question, when you squeeze the brakes very hard. Here's a sketch of the end of ...


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 ...


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