Cheap disk brakes
#51
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I hate rich people !
But Egads -- where on earth did i put my tall rolly ladder? I believe the help left a coo-pon for velveeta in my book on the top shelf! Just venting chaps - but when a man desireth nachos after a long ride, whatcha gonna do?
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Correct - Used 'em on mountain bikes for a long time --- Yes - thru axles are standard now, -- but when bikes as burly as a Santa Cruz Bullitt or Nomad were using QR's years ago ---they're fine for most uses
-- my '17 Tarmac had discs with QR's also - never an issue
#55
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Besides an adjustment problem, this could also be a compatibility issue. Even though the builder was a bike shop, LS could have a mis-match between the levers and the pull required by the caliper. IOW, two sets of junk parts don't like each other. But most likely, it's just the nature of the brakes to need a lot of adjustments.
Piston reversal, is typical on cheap mechanical disc brakes, possibly including bottom end Shimano ones too. The universally accepted reason to this is excessively worn brake pads or installed one of those cheap brake pads with insufficient pad thickness.
The solution is either replace the pads more often and checking your suppliers to make sure you avoid getting pads of insufficient thickness. Or adjust the caliper housing. Make the side the of the caliper with the piston closer to the rotor. It can prevent piston reversal problem and lengthen replacement interval of the brake pads. In most cases, this adjustment technique will also improve brake pad grip reducing the amount of force needed to squeeze the levers.
One thing you need to watch out for with this "offset" caliper adjustment is the stationary pad. The backing plate should NOT protrude beyond the caliper housing. If it starts doing so, then it's time to replace the brake pads or find a new source selling pads with more thickness.
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https://www.bikeforums.net/bicycle-m...d-braking.html
https://web.archive.org/web/20121005...quick_release/
A front disc brake caliper behind the fork blade generates a powerful force tending to loosen a quick release and pull the wheel out of the fork. A special hub, and a fork with a hole rather than a slot for the axle, are needed to surmount this problem.
https://www.sheldonbrown.com/disc-brakes.html
https://diskbrakesqr.wordpress.com/
https://bicycles.stackexchange.com/q...brand-new-bike
https://web.archive.org/web/20121005...quick_release/
A front disc brake caliper behind the fork blade generates a powerful force tending to loosen a quick release and pull the wheel out of the fork. A special hub, and a fork with a hole rather than a slot for the axle, are needed to surmount this problem.
https://www.sheldonbrown.com/disc-brakes.html
https://diskbrakesqr.wordpress.com/
https://bicycles.stackexchange.com/q...brand-new-bike
#57
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https://www.bikeforums.net/bicycle-m...d-braking.html
https://web.archive.org/web/20121005...quick_release/
A front disc brake caliper behind the fork blade generates a powerful force tending to loosen a quick release and pull the wheel out of the fork. A special hub, and a fork with a hole rather than a slot for the axle, are needed to surmount this problem.
https://www.sheldonbrown.com/disc-brakes.html
https://diskbrakesqr.wordpress.com/
https://bicycles.stackexchange.com/q...brand-new-bike
https://web.archive.org/web/20121005...quick_release/
A front disc brake caliper behind the fork blade generates a powerful force tending to loosen a quick release and pull the wheel out of the fork. A special hub, and a fork with a hole rather than a slot for the axle, are needed to surmount this problem.
https://www.sheldonbrown.com/disc-brakes.html
https://diskbrakesqr.wordpress.com/
https://bicycles.stackexchange.com/q...brand-new-bike
For some reason, I never had those problems on disc + QR. I brake aggressively. I ride on city and constantly hit 30 mph on the streets and often had to make full stop in the shortest distance possible from 30 mph. Never had issues losing alignment with such braking treatment.
However, I do tighten my QR quite a bit with two thumbs and then I prevent the QR skewers from opening on its own by zip-tying the ends to the dropout.
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For some reason, I never had those problems on disc + QR. I brake aggressively. I ride on city and constantly hit 30 mph on the streets and often had to make full stop in the shortest distance possible from 30 mph. Never had issues losing alignment with such braking treatment.
However, I do tighten my QR quite a bit with two thumbs and then I prevent the QR skewers from opening on its own by zip-tying the ends to the dropout.
However, I do tighten my QR quite a bit with two thumbs and then I prevent the QR skewers from opening on its own by zip-tying the ends to the dropout.
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And those tires! 40mm party in the front, 25mm business in the back? What am I looking at?
P.S. I've ridden two mountain bikes and now an adventure bike with disc brakes for the last 20 years, and never had a problem with QR and disc brakes, even with the cheapo Giant bike I had in college.
P.S. I've ridden two mountain bikes and now an adventure bike with disc brakes for the last 20 years, and never had a problem with QR and disc brakes, even with the cheapo Giant bike I had in college.
Last edited by autonomy; 05-10-22 at 01:02 PM.
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This suggests the quick release was not properly attached or tightened at that point in time. If it was indeed loose when you were riding, the wheel could have moved in the dropouts and the disc rotor then jammed in the brake caliper.
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Yeah, I read enough at that link to see the same thing: lots of casual cyclists don't know how to us QRs properly, and even plenty of regular riders don't know the difference between an internal cam and an external cam QR -- much less understand why the former is superior to the latter. User error does not equate to poor design.
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Back in the 90s I was leading a group on our club century to Brooklyn. After about 25 miles with ups and downs we stopped for water, etc. As we were leaving a guy picked up his bike out of a rack and his front wheel fell off. He had forgotten to engage his QR. I think that was in the days before lawyer lips were as common.
#63
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Riders on tight budgets, will try out a new tire one at a time. Consider yourself lucky if you can replace both tires on a whim. like I already have long, big cracks on my tires (tires have made around 5000 miles) and have no money for replacement so I have limited my outdoor rides to slow recovery rides only. My real training only happens in the stationary bike for now.
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#64
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LarrySellerz you might find this helpful
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Bear in mind that most cheap mechanical disk brake calipers are of the post mount variety with cheap, low quality IS adapters. It is those adapters that can make it impossible to get the caliper positioned properly for decent braking, even by an experienced LBS mechanic. To keep costs down, the mating surfaces that the actual caliper bolts onto are left unmachined; to make matters worse, some are countersunk too aggressively after they had been drilled and threaded leaving little or no mounting surface to to keep the caliper in proper alignment. Perhaps it was this that the bike shops you took the bike to were experiencing.
With single-piston mechanical disk brakes, it has been my experience that the ideal way to adjust caliper positioning is to use an old, worn brake pad first. Allow me to explain.
Slip the spent brake pad into the non-piston (stationary) side as you normally would. Now, turn the adjustment bolt in so that the back plate of the pad (the metal part) sits just a little recessed from the inner surface of the caliper (directly facing the rotor.) Now - assuming that your IS adapters will cooperate (see above) - position the caliper so that what's left of the spent pad's braking material barely touches the (perfectly trued) rotor - leaving a little daylight in between, just so - and tighten the two bolts down.
Now back the non-piston adjustment bolt all the way out, install the first new pad, and then turn it back in to get the braking material as close to the rotor as possible, with just a little daylight between the two (with no rubbing.) this will ensure that the rotor won't flex much when the other, piston-actuated pad presses on it from the other side.
Slip the other pad in; make sure that the actuation arm is released all the way to its resting position, pull the cable tight by hand and tighten the anchor bolt.
Don't forget to readjust the non-piston pad ad it wears down every so often.
With single-piston mechanical disk brakes, it has been my experience that the ideal way to adjust caliper positioning is to use an old, worn brake pad first. Allow me to explain.
Slip the spent brake pad into the non-piston (stationary) side as you normally would. Now, turn the adjustment bolt in so that the back plate of the pad (the metal part) sits just a little recessed from the inner surface of the caliper (directly facing the rotor.) Now - assuming that your IS adapters will cooperate (see above) - position the caliper so that what's left of the spent pad's braking material barely touches the (perfectly trued) rotor - leaving a little daylight in between, just so - and tighten the two bolts down.
Now back the non-piston adjustment bolt all the way out, install the first new pad, and then turn it back in to get the braking material as close to the rotor as possible, with just a little daylight between the two (with no rubbing.) this will ensure that the rotor won't flex much when the other, piston-actuated pad presses on it from the other side.
Slip the other pad in; make sure that the actuation arm is released all the way to its resting position, pull the cable tight by hand and tighten the anchor bolt.
Don't forget to readjust the non-piston pad ad it wears down every so often.
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#66
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And those tires! 40mm party in the front, 25mm business in the back? What am I looking at?
P.S. I've ridden two mountain bikes and now an adventure bike with disc brakes for the last 20 years, and never had a problem with QR and disc brakes, even with the cheapo Giant bike I had in college.
P.S. I've ridden two mountain bikes and now an adventure bike with disc brakes for the last 20 years, and never had a problem with QR and disc brakes, even with the cheapo Giant bike I had in college.
Last edited by LarrySellerz; 05-11-22 at 01:17 AM.
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For some reason, I never had those problems on disc + QR. I brake aggressively. I ride on city and constantly hit 30 mph on the streets and often had to make full stop in the shortest distance possible from 30 mph. Never had issues losing alignment with such braking treatment.
However, I do tighten my QR quite a bit with two thumbs and then I prevent the QR skewers from opening on its own by zip-tying the ends to the dropout.
However, I do tighten my QR quite a bit with two thumbs and then I prevent the QR skewers from opening on its own by zip-tying the ends to the dropout.
As we go into the future all of the good bikes will be sold with thru axle. QR will be reserved for department store bikes and entry level bikes.
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Yeah, I read enough at that link to see the same thing: lots of casual cyclists don't know how to us QRs properly, and even plenty of regular riders don't know the difference between an internal cam and an external cam QR -- much less understand why the former is superior to the latter. User error does not equate to poor design.
#72
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That's totally fine with me. But never really had issues with QR and disc. Maybe it has something to do with the drop out design. Some keeps the QR from moving around.
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nah cubewheels, he was under the impression that the manufacturers "limit" on the tire pressure means that if you exceed it you risk malfunction. This is just untrue, unless you double the max pressure or something