Why are "singlespeed" hubs "bolt on"?
I've been wondering about this for a while. My understanding is that quick-releases can provide anywhere from about 700-1400 LBS of clamping force (depending on manufacturer and QR-style), which is considerably more than can be applied with either tradition nutted axles (full length axle with track/floating washer nuts) or "bolt-in" style axles (hope, CK, dt-swiss, etc, style hubs).
The only legitimate arguments i've seen so far are:
1: Nutted style bolt on hubs can possibly have a larger contact area with the dropout/forkend compared to many quick releases. This may aid significantly in holding power.
2: Bolt-on style hubs (not bolt-in, think surly hubs or similar) allow for easy use of chain-tugs which, when used properly, pretty much prevent any possibility of the hub slipping.
3: a bolt style hub cant get caught on something and accidentally open up. I think this mostly applies to BMX racing and track racing.
So what other arguments can anyone think of?
As far as personal experience goes, I've had both Surly hubs and Hope hopes with nutted axles and and bolt-ins, respectivly, and they both needed chain-tugs to prevent slipping.
My road bike, with 34-25 max low gearing, has never slipped in semi-horizontal dropouts with just a stock shimano QR
Last edited by Slurry; 01-16-2010 at 09:42 PM.
I use QR rear axles on both my singlespeeds.
One frame has vertical dropouts.
The other, horizontal track ends w/chain tugs.
I much prefer the former, FWIW.
i would have to agree, im just trying to figure out why many of the manufactures sell their singlespeed hubs stock with some type of bolt on/in mechanism.
Originally Posted by Sparticus
With surly, hope and paul bolt on/in hubs, I've never needed a chain tug. With quick releases, I've almost always been able to get them to slip. Good qr's too, Salsa and XT. I think the difference comes down to flex. A QR has not only a little bit of wiggle room inside the hollow axle, but can flex under load, as can the hollow axle, more easily than a solid axle or large diameter hollow axle. That flexing allows the wheel the slip more easily than the clamping force would have you believe.
DT claims that they're RWS skewer won't slip on track ends.
DT is wrong.
Originally Posted by Schmucker
I bought the RWS skewer to get away from needing a chain-tug but no such luck. I've haven't had any luck preventing any QR from slipping w/ track ends. But now that I have a bike with vertical drops I do prefer the RWS over traditional QRs.
Conversely, bolt-ons with good bolts have always stayed put for me.
Bolts can be torqued/tightened to provide greater pressure on a horizontal dropout than a QR. If you're running a chain tug, this is largely unnecessary - same for a vertical dropout/EBB. Probably influence from the track side, where hubs are nutted.
Happy in Happy Valley
I have found that with an XT quick release I need a chain tug, and with a bolt-on axle I do not. This seems to be typical around here... I assume most manufacturers sell bolt on SS hubs because that's what seems to work best in the real world.
OP: Where did you find that data on QR vs. Nutted axle clamping force? Just curious. I have always assumed that the clamping force is on the same order.
I think that the surface of the nut is critical. At the same clamping force, the friction force should theoretically be the same between the two arrangements. However, the larger surface of the nutted axle has more teeth than the QR, allowing it to bite the paint more effectively. At least that's been my theory.
Sean's thinking on axle flex also sounds logical. If the axle flexes, the nut/QR is lifting on one side, reducing the number of teeth engaged on the paint and possibly allowing slip.
Rigid Surly 1x1 650b--------Fixed CrossCheck--------Surly Pacer-------Salsa Ala Carte
Where to begin; First while a QR max'es out at your 1400 lbs, the clamping force on a 10mm axle at 30 ft lbs torque is over 4500 lbs., so your statement that a QR is more powerful than a nutted axle is way flawed. Further, QR's are rarely used "track fork ends", (BMX, Track Bikes, one speed cruisers) and it is only recently that singlespeeders have even attempted to use them with very limited success.
Originally Posted by Slurry
1. Nutted axle not only have a larger contact area, but can be tightened with 4 times the clamping force. With exception of older Campy QR's, skewers only have one steel clamping surface, while the other is usually aluminium; most the inferior exterior cam QR's have aluminium on both surfaces; aluminium is self lubricating on steel.
2. Chain-tugs came out of the Velodrome, but really aren't very popular with riders (it's the added weight) Besides track applications, the primary use for chain-tugs is ease of adjustability, and the use of QR's on singlespeeds with track- ends.
3. True, bolted axles can not accidentally "pop" loose, however since QR's are never seen on track bikes and rarely on BMX bikes, it's pretty much a none issue.
Other arguments? Well you haven't discussed that popular, non-Shimano, exterior cam QR's have only 1/2 the clamping force of interior cam QR's. Exterior QR's are so weak, they can easily fail when using disc brakes, even with fork dropouts. If you have had axle nuts slip than you either used inferior track nuts, have paint built up on track end surface, or your simply not tightening the nut hard enough.
No one said a QR will not work on a road bike with horizontal dropouts (heck that was the type of setup it was designed around), but that is a world away from track ends. With track ends, the chain forces pull on the axle in a straight path; horizontal dropouts actually face down, meaning a percentage the chain forces on the whatever is being used to hold the hub in place, is used up pulling the axle not only back, but down.
Anyway, that's my arguement. I have bikes with pretty much every configuration and I know what works on which dropout/ track end; believe what you will, but a QR is no where as strong as a nutted axle.
Last edited by aka brad; 01-18-2010 at 12:17 AM.
Just one more rep and I get the toaster!
I don't now how much a QR contact area matters. Being it has some play relative to the axle itself, a lot of the actual holding has to be coming from the axle end and inner part of the dropout, not the quick release. Some bolt setups are like this as well, but to a lesser degree.
The biggest problem is the shaft size of the quick release allows it to be more elastic. Steel is stiffer than the Ti ones sure, but the size restriction is still there (and the tensioned area is way longer than bolt setups). I would think no matter how good the QR mechanism is, it is still somewhat limited by it being more prone to "stretch" under stress.