Why is there a spring in my front v-brake, but not in the rear?
#1
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Why is there a spring in my front v-brake, but not in the rear?
The fittings at the tops of the front and rear noodles are different. The rear has a smaller fitting. The front has a larger fitting with a spring down in the barrel. Anyone know the reason for this?
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You have a failed attempt by Shimano to make an antilock brake system. The spring is meant to keep the front wheel from ‘locking’ (it can’t but that’s a different discussion). It doesn’t work and makes the front brake spongy. It would be better to just replace it with a regular noodle.
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#3
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You have a failed attempt by Shimano to make an antilock brake system. The spring is meant to keep the front wheel from ‘locking’ (it can’t but that’s a different discussion). It doesn’t work and makes the front brake spongy. It would be better to just replace it with a regular noodle.
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Many OEMs called them "power modulators" and marketed them as a feature. They're somewhat common on front linear pull brakes, especially on hybrid bikes and bikes marketed towards the recreational riding crowd.
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My wife's Trek came with one of these. I had never seen one and was a bit mystified why the brake felt spongy. Now, I'm mystified why anyone thought this was a good idea.
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The spring is to stop people like that from killing themselves. It takes a while lot more effort to lock up the brake and OTB. [edit: I am not saying that it's effective, but that's the intent.]
Last edited by mack_turtle; 09-25-20 at 12:28 PM.
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Former bike shop employee here: I once had a customer return a bike because it was "dangerous." She was an unskilled rider and took her v-brakes equipped hybrid down a hill, stood up, and grabbed a handful of front brake in a panic. Went over the bar and was seriously injured.
The spring is to stop people like that from killing themselves. It takes a while lot more effort to lock up the brake and OTB.
The spring is to stop people like that from killing themselves. It takes a while lot more effort to lock up the brake and OTB.
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after test-riding dozens of bikes with those springs, I can say with 100% confidence that the spring adds some modulation into a system that is otherwise on/off only. some modulation, but not a lot. it's not enough to prevent a really stubborn person from flying OTB, but it helps. a person with an ounce of sense would feel the warning from that spring mechanism and probably back off the brakes before that. it's supposed to be the bike manufacturer's liability safeguard. it's minimally effective, but it's better than nothing when you put grandma on a bike she points her bike at a hill with no idea what she's doing.
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after test-riding dozens of bikes with those springs, I can say with 100% confidence that the spring adds some modulation into a system that is otherwise on/off only. some modulation, but not a lot. it's not enough to prevent a really stubborn person from flying OTB, but it helps. a person with an ounce of sense would feel the warning from that spring mechanism and probably back off the brakes before that. it's supposed to be the bike manufacturer's liability safeguard. it's minimally effective, but it's better than nothing when you put grandma on a bike she points her bike at a hill with no idea what she's doing.
People don’t go over the bars because of the brakes all that often and, if they do, the reason is usually less the fault of the brake than the technique. Standing up and braking on a downhill like your customer describes isn’t the fault of the brake and no little spring would have done much to have done much to prevent her from going over the bars.
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People don’t go over the bars because of the brakes all that often and, if they do, the reason is usually less the fault of the brake than the technique. Standing up and braking on a downhill like your customer describes isn’t the fault of the brake and no little spring would have done much to have done much to prevent her from going over the bars.
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after test-riding dozens of bikes with those springs, I can say with 100% confidence that the spring adds some modulation into a system that is otherwise on/off only. some modulation, but not a lot. it's not enough to prevent a really stubborn person from flying OTB, but it helps. a person with an ounce of sense would feel the warning from that spring mechanism and probably back off the brakes before that. it's supposed to be the bike manufacturer's liability safeguard. it's minimally effective, but it's better than nothing when you put grandma on a bike she points her bike at a hill with no idea what she's doing.
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for people who are used to crappy brakes who grab the lever with four fingers instead of one or two, v-brakes are too much. unfortunately, bike manufacturers have to design for the least common denominator of clueless new riders, which is why they equip these bikes with "gear indicator windows," QR levers that are "easier to use," and little springs in the brake noodles.
aren't people apparently concerned with "catapulting disc brakes"?
aren't people apparently concerned with "catapulting disc brakes"?
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I agree with you 100% on this. If I recall correctly, this was on an Electra Townie too, which is a big old barge of a bike and very difficult to crash like that. Like I said, the spring is a bike manufacturer's attempt at "liability insurance" for people who are really stubborn and foolish with their bikes. you can't make people not crash their bikes, but it's a good idea to try to make it more difficult to do so.
for people who are used to crappy brakes who grab the lever with four fingers instead of one or two, v-brakes are too much. unfortunately, bike manufacturers have to design for the least common denominator of clueless new riders, which is why they equip these bikes with "gear indicator windows," QR levers that are "easier to use," and little springs in the brake noodles.
aren't people apparently concerned with "catapulting disc brakes"?
aren't people apparently concerned with "catapulting disc brakes"?
The Consumer Product Safety Commision, by the way, doesn’t like lawyer lips. They don’t require them and think that they are not a good solution.
*”Done Falled Over”
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Last edited by cyccommute; 09-25-20 at 11:00 AM.
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I think you are dealing with a JRA situation. Without doing the calculations, I would say that a Townie would be next to impossible to do an endo...with any kind of brake and in any rider configuration. The Townie is longer and has a lower center of gravity than a regular bike which makes it next to impossible to lift the rear wheel and send the rider over the bars. It’s more like a tandem or recumbent that a tradition double diamond frame. I’d suspect that you could even skid the front wheel ...something that is impossible with a regular bike...before the rider would go over the bars. I have no doubt that the woman crashed and probably ended up on the ground with the bike somewhere behind her but she never went “over the bars”. She just DFOed* and thought the brakes were to blame.
*”Done Falled Over”
*”Done Falled Over”
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mack_turtle The thing about the disc brake ejecting a wheel is that the problem can develop over time and repeated stopping, which can cause micro-movements of the axle in the dropouts and eventually loosen the QR. The (erroneous) thinking behind Direct-pull brake 'power modulators' is that the possibility of the front brake sending you arse-over-teakettle is potentially built in to properly functioning brakes from day 1.
The solution is probably education - shops should be informing clients when they pick up their new bikes that a ham-fistful of front brake could be hazardous, and that they should be practicing using the front brakes to be proficient before attempting speed runs down a mountainside. In the early days of V brakes I tried to make each customer aware that the new style of brakes is likely much more than to what they were accustomed.
The solution is probably education - shops should be informing clients when they pick up their new bikes that a ham-fistful of front brake could be hazardous, and that they should be practicing using the front brakes to be proficient before attempting speed runs down a mountainside. In the early days of V brakes I tried to make each customer aware that the new style of brakes is likely much more than to what they were accustomed.
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Former bike shop employee here: I once had a customer return a bike because it was "dangerous." She was an unskilled rider and took her v-brakes equipped hybrid down a hill, stood up, and grabbed a handful of front brake in a panic. Went over the bar and was seriously injured.
The spring is to stop people like that from killing themselves. It takes a while lot more effort to lock up the brake and OTB.
The spring is to stop people like that from killing themselves. It takes a while lot more effort to lock up the brake and OTB.
I'd expect that your customer would have gone over the bar even with this device. Standing up and panic braking is a skill that few will ever master.
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Yeah, I get the intent, but deliberately making the brake less effective because they're concerned about their liability exposure is a questionable strategy. Better off fitting the bikes with rear brakes only.
I'd expect that your customer would have gone over the bar even with this device. Standing up and panic braking is a skill that few will ever master.
I'd expect that your customer would have gone over the bar even with this device. Standing up and panic braking is a skill that few will ever master.
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YouTube would not be as entertaining if people stopped being stupid.
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I didn't sell enough bikes to remember the specifics—I was in the shop more than the sales floor—but I recall making a customer sign something about wearing a helmet, obeying road rules, not riding in the dark without lights, etc. no one read it, they just signed it. i was all totally common sense stuff anyway.
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All Bikes came from the manufacturer with an 'owners manual', which included lawyerly words about the risks of cycling being your own, but had very little value otherwise. This owners manual sometimes got passed to the client at the point of sale and sometimes not.
Occasionally people we forgot to give them to would storm back in a few days later and demand they be given the owners manual, as if we kept it from them for some nefarious purpose or were selling them on the black market.
Occasionally people we forgot to give them to would storm back in a few days later and demand they be given the owners manual, as if we kept it from them for some nefarious purpose or were selling them on the black market.
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