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Disc brake ejection redivivus: Shimano solves it?
Somehow I didn't notice this earlier, but James "Angry Asian"* Huang
reported on some early 2009 Shimano component updates: http://www.cyclingnews.com/tech.php?id=tech/2008/features/shimano_09_08 One of the biggies is a new through-axle standard aimed at the cross-country set. It's called E-Thru. They have a bunch of vaguely-defined advantages for this new structure, but here's the thing: -it's a design clearly aimed at eliminating slotted fork ends from all mountain bikes, even light ones. -it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Share & Enjoy, *No really: www.angryasian.com is James' moribund site -- Ryan Cousineau http://www.wiredcola.com/ "My scenarios may give the impression I could be an excellent crook. Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing |
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Disc brake ejection redivivus: Shimano solves it?
On Mar 4, 1:58*am, Ryan Cousineau wrote:
-it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. |
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Disc brake ejection redivivus: Shimano solves it?
Marz Jennings wrote:
-it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. You must have missed the discussion of this issue in which I think the effect of a trailing caliper causing a separation force was established beyond doubt. What was not established was how many riders failed to secure the QR adequately to have a separation. The argument that "It never happened to me" is not proof that it is not a reasonable possibility. Interestingly, some of the folks who claim there is no hazard with such disk brakes are at the same time for helmet requirement laws. Jobst Brandt |
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Disc brake ejection redivivus: Shimano solves it?
Marz wrote:
On Mar 4, 1:58 am, Ryan Cousineau wrote: -it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. It actually has been a recurring problem. See "http://www.singletrackworld.com/article.php?sid=1063" |
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Disc brake ejection redivivus: Shimano solves it?
Marz wrote:
Ryan Cousineau wrote: -it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. Maybe you don't think disc wheel ejection with a properly tightened skewer is a problem (FWIW, I have observed shifting of the front wheel from braking), but how about solving the problem of automatic ejection of wheels whose QRs were not adequately tightened, or not tightened at all? A through-axle can be left completely loose with almost no chance of the wheel going astray. With more and more low-priced/high-volume bikes coming equipped with discs these days, I think it's a perfectly reasonable thing to introduce a safer, structurally sounder front axle system. I don't know why an interchangeable refinement of a 20mm through-axle won't do the job, but then it seems Shimano don't want to manufacture anything whose design they can't own outright. Chalo |
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Disc brake ejection redivivus: Shimano solves it?
On Mar 4, 1:00*pm, wrote:
Marz Jennings wrote: -it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. You must have missed the discussion of this issue in which I think the effect of a trailing caliper causing a separation force was established beyond doubt. *What was not established was how many riders failed to secure the QR adequately to have a separation. The argument that "It never happened to me" is not proof that it is not a reasonable possibility. *Interestingly, some of the folks who claim there is no hazard with such disk brakes are at the same time for helmet requirement laws. Jobst Brandt I lurked through most of that conversation and while I agree that a 'downward' force does exist during braking. I've not seen anything to prove that this force is sufficient to eject a wheel that's tightly held in place by a QR. Having read Ben's research before... http://www.kinetics.org.uk/html/disc_brakes___qrs.shtml ... I may concede there's a problem for loose QR's, but would addressing this problem be just pandering to incompetent folks who fail to tighten QR's correctly (i.e. lawyer lips again)? If a 15mm through axle does fix such a problem you'd have thought Shimano would have promoted such a feature. They have nothing to loose by admitting such a design flaw as they don't make any forks themselves. ttfn, Marz |
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Disc brake ejection redivivus: Shimano solves it?
On Tue, 4 Mar 2008 12:10:31 -0800 (PST), Chalo
wrote: Marz wrote: Ryan Cousineau wrote: -it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. Maybe you don't think disc wheel ejection with a properly tightened skewer is a problem (FWIW, I have observed shifting of the front wheel from braking), but how about solving the problem of automatic ejection of wheels whose QRs were not adequately tightened, or not tightened at all? A through-axle can be left completely loose with almost no chance of the wheel going astray. With more and more low-priced/high-volume bikes coming equipped with discs these days, I think it's a perfectly reasonable thing to introduce a safer, structurally sounder front axle system. I don't know why an interchangeable refinement of a 20mm through-axle won't do the job, but then it seems Shimano don't want to manufacture anything whose design they can't own outright. The first time I leapt aboard this particular train, I noted that even DH caliber 20mm through axle hubs only added a couple of ounces over a similar quality 9mm QR hub, so there certainly doesn't seem to be a need to re-invent the wheel. There's no good reason why 'XC20' shouldn't use exactly the same interface dimensions as 'DH20', just with smaller wall thickness on the axles and axle clamps, for example, to reflect the lower expected loadings. I expect Shimano's 'problem' was that, although a standard 20mm hub will take a standard 6-bolt IS disc, it won't take the original Centrelock, so they had to invent a bigger, incompatible, Centrelock for Saint and Hone. I'm guessing a 15mm through axle will work with XT/XTR type Centrelock rotors. Kinky Cowboy* *Batteries not included May contain traces of nuts Your milage may vary |
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Disc brake ejection redivivus: Shimano solves it?
On Mar 4, 1:11*pm, SMS wrote:
Marz wrote: On Mar 4, 1:58 am, Ryan Cousineau wrote: -it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. It actually has been a recurring problem. See "http://www.singletrackworld.com/article.php?sid=1063" I don't think dragging up a 5 year old article qualifies as recurring. |
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Disc brake ejection redivivus: Shimano solves it?
On Mar 4, 2:10*pm, Chalo wrote:
Marz wrote: Ryan Cousineau wrote: -it doesn't mention anything about disc-brake wheel ejection, but it will clearly fix that. Yes, that's nice that you think a 15mm through axle will fix a problem that didn't exist in the first place. Maybe you don't think disc wheel ejection with a properly tightened skewer is a problem (FWIW, I have observed shifting of the front wheel from braking), but how about solving the problem of automatic ejection of wheels whose QRs were not adequately tightened, or not tightened at all? *A through-axle can be left completely loose with almost no chance of the wheel going astray. With more and more low-priced/high-volume bikes coming equipped with discs these days, I think it's a perfectly reasonable thing to introduce a safer, structurally sounder front axle system. *I don't know why an interchangeable refinement of a 20mm through-axle won't do the job, but then it seems Shimano don't want to manufacture anything whose design they can't own outright. Chalo So the problem is really with riders who fail QR 101. Fair enough, this is why we have lawyer lips in the first place. I'm all for through axles as they address a whole bunch of torsion issues for front forks, I ride a 66 with a 20mm axle myself. The maxle from rockshox allows you to run a 20mm and still have a QR wheel... http://www.pinkbike.com/photo/410099/ And I suspect you're right about shimano not wanting to integrate with existing technology. Take for example their approach to disk brakes and the use of centre lock. |
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