riderlife

The other day i was building a 29'er with mechanical disc brakes and i naturally put the skewer with the handle on the left side with the disc brake. iv always done this cuz well on every other bike thats how it goes and cuz an other mechanic who's also a mountain biker puts his front skewer on that side and thats what an old head mechanic taught me. but then my boss gave me crap and told me to put the handle on the right side cuz it gets in the way of the brake. Is there a necessary way to put on a skewer on a mountain bike with disc brakes? as you can tell im not an avid mountain biker

FBinNY 

Which way you use a skewer doesn't matter to the skewers function either way. Rear skewers are usually inserted with lever to the left to keep the lever away from the derailleur upper body. Most people do the front the same way to be consistent, and also because with traditional internal cam levers it had the lever facing the right way.

If there's no reason to change the lever to the right side, I'd do both to the left (out of tradition). But if the disc brake body is in the way than reversing the skewer makes sense.

TacomaSailor

Interesting that you should ask the question today.

Last week I thought I had broken the cable for the rear derailleur in the middle of a ride that had me 5 miles from the car which was on the other side of a mountain. Moving the thumb lever just put more slack into the cable but the chain would not move to another gear.

I rode back to the car with the chain fixed on the 24 tooth rear gear.

Once back to the car I took a closer look at the rear derailleur. I saw that the quick release lever, which was on the gear side, had rotated 45 degrees downward and was pressing inward on the XTR cage. The lever was hard against the cage and had pushed the cage so that the chain would only engage the 24 tooth gear.

Just before I had the problem the rear derailleur had been working very well and shifting smoothly. I had just ridden thru some pretty gnarly rock with some narrow gaps between them. I had heard the wheel whack some rocks pretty hard. Somehow one of those rocks had rotated the quick release DOWNWARD and Inward.

I check the quick release levers several times while riding. About five minutes earlier I had checked both levers just before dropping off a 25% down slope that lost about 500'. The rear quick release had been pressed hard up against the rear triangle tube that extends upward toward the seat (seat stay?).

Either a rock caused the lever to rotate or ??? something else caused that lever to rotate downward, and inward,

I've never had this problem in 30 years of mountain biking but the rear lever has almost always been on the left side. The lever is now back to the left side where it can't effect the shifting.

JonathanGennick 

I like my front skewer levers pointing rearward. It's usually easy enough to angle them such that they do not hit the disc rotor or brake caliper. I prefer them to come in from the left side.

However, Shimano-brand skewers are asymmetrical. I just built a bike with the front skewer coming in from the right so that the lever can be under the cam where it can clear the fork and point backwards.

xenologer

Why argue over what side the skewer is pointed? when there's the even bigger issue of:
you shouldn't be using a quick release on a front disk hub anyway, risk wheel ejection under heavy braking.

Unless of course, this is the rare properly designed fork where the disk brake is on the frontside of the right leg so ejection isnt an issue.
Coiencidentally, that would also let you have the skewer pointed traditionally without cluttering the brake...

FBinNY 

It doesn't matter which side the brake is on as long as the it's forward of the blade so it engages a downcoming rotor. However QRs have been used on forks with rear mounted disc brakes for over a decade and wheel ejection from braking is rare (if ever). This may be due to the weight shift on braking driving the fork down onto the axle, the so called lawyers lips, or because decent QRs have tremendous holding power, rivaling and in some cases surpassing that of nuts.

As I said earlier, left front levers are more a matter of tradition, and the QRs should be installed in whichever direction makes the most sense for any particular bike.

JonathanGennick 

It's also not always feasible to avoid QR forks. My 2011 El Mariachi came with a QR fork that has *only* disc mounts. I'd have been thrilled if the matching fork had come with 15mm thru-axle support, but it comes QR, and so I must build it that way, or not build it at all.

fietsbob

Just consider the simple reason.. there is more space..

You can close the QR, fully, with out putting your Knuckles into the disc..

(my disc brake set is on the commuter, it's allen bolt skewer has no lever)

DiabloScott

The Park Tools site doesn't specify one way or the other, but it has photos showing both ways.
I conclude it's a minor issue - not worth yelling at an employee about, but any particular shop can have a standard that the owner wants to follow.

fietsbob

NB: When you hit the brakes the pad becomes the axis of torque.

that is what that arrow is suggesting.

that is also why it is better to put the lever on the right side ,
so the QR is easily closed fully, and tight,
to avoid the wheel coming out.

JonathanGennick 

I'm looking at that photo and thinking I could fix all my forks by turning them around.
...
...
...
Just kidding!

DiabloScott

Yes, that came from a wheel ejection article on the PARK website, but they weren't suggesting that the QR should be moved, they were just suggesting that you understand the issue and make sure the QR is closed properly. The two photos came from different articles, it was just me that combined them just for this thread. Neither one was about proper QR placement.

One of the suggestions of the wheel ejection prevention squad, was that the caliper be moved to the front of the fork so that the torque would tend to keep the wheel in the dropouts, so you're not that far off.

IthaDan 

I have NEVER heard this. Seems a little paranoid to me. I guess on a Walmart bike, coupled with improper QR use, it MIGHT be an issue, but...

JonathanGennick 

It's been a known issue for many years now. Here's a link to some information: https://www.ne.jp/asahi/julesandjames...quick_release/

riderlife

Wow iv never even heard of wheel ejection from braking i can see something like that happening from improperly tightening a skewer. i wonder if anyone has had that problem with the dt swiss ratcheting skewer and for those of you wondering y i was putting a skewer in the front, it came like that out of the box it was a trek marin s/s from the gary fisher line

JonathanGennick 

Am pretty sure the risk is low. However, I believe it is why many modern forks have forward facing dropouts.

FBinNY 

You probably never heard of it because it's one of those things that could happen ....in theory, but doesn't in practice.

The holding power of QR's is pretty high so it would take a significant force to over come that and rip the wheel out. Also consider that during a hard braking of this type the fork would be driven down onto the axle by the braking weight shift.

Then consider that there's a cap on the amount of braking force that can be generated in the front wheel. Long before there's enough braking force to eject the front wheel, the engine will be ejected over the front wheel.

onespeedbiker

Have you actually read any of this. It assumes that you never re-check your QR to the point that the non-lever side loosens so much it is able to slip over the safety tabs! Of course using the same logic, the same thing would also happen with axle nuts.

Again, if there is a problem here, it is failure to properly use a QR; gee I always check my QR's before a ride. How about you? OTOH I did have a disc wheel slide on the track forks of my Bianchi SASS until I switched out the QR's from the outside cam crap that Stan's uses with their wheels to a generic inside cam version (Velo Orange) and I've not had and problems.

oldbobcat

Some riders like it on the left because that's conventional. Some like in on the right because it reduces the risk of carelessly squeezing the rotor with your hand while tightening down the quick release. In our shop we leave it on whichever side we find it.

Regarding the danger of quick release hubs and disc brakes, the evidence looks pretty specious. While the experts cited in the Gennick link have specific areas of expertise, their significant work was done decades agon, and none are especially qualified in the area of disc brakes. In this context, I would even venture to label them blowhards. The Cannondale memo isn't helpful because it doesn't describe the braking system used in their test. Five pounds of pressure on the lever is quite insufficient for a some cheap mechanical systems, but this can be significant force on the hydraulic systems that advertise "one-finger braking." The author's own writing is full of inflammatory language, such as "shocking" and "eureka," and the story of the actual case focuses more on the cyclist's injuries than what actually happened.

It doesn't make sense to me. First, the braking force needs to somehow undo the cam on the quick release. Then it needs to loosen the nut enough to get it around the safety tabs on the fork. Sure, a case was settled in the UK, but that doesn't rule out the possibility of user error or mechanical failure outside the realm of the quick release.

JonathanGennick 

Yeah, I agree. The author of that site really does his credibility no favors.

Here is a more thoughtful discussion with some interesting comments from Jobst Brandt:

https://yarchive.net/bike/disk_brake_qr.html

Here is an anecdotal account that could be as much the result of a loose skewer as of braking forces:

https://forums.mtbr.com/29er-bikes/ri...ke-172820.html

I also note that it's become common for fork dropouts -- in the mountain-bike world -- to be made facing forward instead of downward. That's done to resist the downward forces from braking. The above discussion thread mentions that at the end. The guy from On-One / Titus gives a clear warning against downward facing dropouts.

Really, I'm sure the risk is quite low else we'd be hearing all sorts more anecdotal accounts. Forward facing dropouts probably help a lot. However, I am still happy at the move towards thru-axles all around. And if I must use a QR fork, then I prefer one with the forward-facing dropouts. (I also am happy to have the lawyer lips).

MichaelW

The main reason for putting the QR lever on the non-disc size is to avoid contamination of the disc by grubby-pawed workshop-monkeys and to avoid the risk of burning your hand when you remove a wheel with a hot rotor.
The wheel ejection problem may be Low Risk but the consequences are Really Bad. It makes sense to use internal cam QRs from Shimano/Campagnolo rather than the external cams lightweight ones with nylon bearing surfaces. Lawer lips and forward sloping fork dropouts will help.
In the UK, one small brands puts the disk mount on the front surface of the right leg. Braking now forces the wheel into the dropout.

JonathanGennick 

Really? I am just curious -- do you remember the brand?