How Tight?
 

I have a track bike with a carbon fork. The dropouts, on the fork, appear to be carbon sandwiched between a piece of metal on each side. Just curious, how much torque should I use to tighten the axle bolts? The same as I would for aluminum or steel dropouts?

Thanks.

Good design would dictate that the dropouts should tolerate full (same as for steel) tightening on the axle nuts, especially in back. It's hard enough to get rear wheels so they don't slip under chain load, so it would be poor design to force someone to back off from properly and fully securing his wheels.

That said, I'd shoot for the lowest torque that I felt i could trust to hold my wheels on, and keep the rear from slipping.

I'll let the engineers debate design goals and material limitations, but I know of a number of situations where carbon instead of steel/AL requires torque levels different then the metals.

When I first read this post earlier I was going to say that just tight enough was the best amount but in hind sight that means you need to have had slippage at least once. I don't know if I'd want the chance to gauge up a carbon drop out experimenting.

Does the OP have contact with the manufacturer or does the seller have info? The Op is wise to worry. Andy.

I agree that the OP has reason to worry, or at least may have. But he has no choice about getting wheels tight enough not to slip. So a reasonable coarse of action is to use track nuts and axle faces with good bite, so h gets the most hold for any compression, then err low on the torque, and go tighter if the wheels slip. I wouldn'y worry about the front wheel, it doesn't need an awful lot to stay put. It's the rear that may or may not be a problem.

Of course. But I'll quibble in that just as the OP had the choice to not buy this bike he also has the choice to move it along before he mounts wheels. Harsh? Maybe, but I don't have as much confidence in some of the carbon products that are in the market place as some do. Andy.

Thanks for your input, everyone.

I reread my original post and it doesn't seem all together very clear. What I meant to ask was, how much torque do you think is required, for the axle nuts, on the carbon fork?

The rear dropouts don't concern me much as they are aluminum with steel plates. My main concern is, how much torque is enough, on the front carbon dropouts, to hold the wheel in place while not harming the carbon?

Like you, I probably wouldn't buy a frame with this type of dropout, especially for track use. OTOH, I tend to be conservative and prefer bikes that are forgiving of rough treatment, and offer maximum margins of error between what's necessary, and what the frame can take.

But we weren't asked about the choice, only about how to approach axle torque. My advice is actually consistent with how I approach tightening just about everything on bike. I use enough torque to do the job, no more, no less. Torque spec can be a useful guide, but I prefer the old school of feeling, not the torque per se, but how the fastener is responding.

I'd tighten them pretty close to what I usually do, but I can't give you a number because of what I explained above as you were writing your second question. I never tighten front wheels as tight as rears anyway, but I don't stint of baby carbon forks any more that I do metal ones.

It's a front wheel, tighten it to where you feel you can trust it at any speed.

Thanks. Yes, that's what I've been doing and all seems to be fine (so far). I was just curious if there was a more "precise" way of approaching this, especially since I'm dealing with carbon.

What does the manufacturer have to say about this? They (presumably) designed it, and should be aware of its limitations, so should be the best source of this kind of information.

I haven't contacted the manufacturer about this. However I have tried contacting them about some other questions (only minor things, much like this), and I have yet to hear back from them. They are sort of...non responsive (much like many of the bike component manufacturers I've reached out to in the past). So, I figured I wouldn't waste my time trying to contact them.

Front wheels don't need to be that tight. I've had instances where I've crashed and then noticed the front wheel is out of alignment because it moved in the fork ends. No big deal, loosen it up and re-tighten in the correct spot. The thing you really don't want to have happen is it to fall out when you wheelie, or loosen up on its own. So tighten it like you would on a normal fork but no need to crank it down.

Rear wheels, of course, DO need to be tight to prevent slippage with horizontal dropouts or track ends. I tighten those about as much as I can, especially on my fixed gears (I should note I'm talking about quick release skewers on my bikes, not track nuts.)

If you don't have disc brakes, there is very little force acting on the front axle. If your track bike is actually for the track and not just a fixie for street use, the only force acting on the dropouts is the weight of the bike and rider pushing the axle into the dropouts, and so I would say they need to be good and snug, but not too tight. Sorry I have no torque numbers to equate this to.

I have two bikes with Easton carbon forks that are 100% carbon, even the dropouts, and they have no metal reinforcements. I have always tightened the qr skewers (Shimano and Campy internal cam type) to the same tension as I do for aluminum and steel dropouts and have never had any problems. After 33,000 miles on one bike and 29,000 on the other, if I was going to damage the dropouts I believe the problem would have shown up by now.

Best answer.