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

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.

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

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"

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

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

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

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.

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.