geepondy

I have a Specialize Roubaix, first experience with a thru-hole axle (no quick release levers). I recently had the bike shop change out my tires but one of them wasn't holding air so I thought I would investigate/change the tube myself. Using a standard 6mm hex wrench, it seemed the axle was not very tight - perhaps a quarter turn past the hand tightening point. I haven't put it back yet but it seems like there was plenty of room before it would start to get difficult to turn with the hex wrench and one would have to "force it" to further tighten (which I assume one does not want to do). From what I read it seems like typical axle torque settings are 10-12 Nm which seems like that is a lot higher than what the axel was tightened to. In absence of a torque wrench which I think costs about $100 (plus would not have on hand anyways for a field repair), roughly how tight should the axle be tightened to? To the point of where it gets difficult to turn the hex wrench further without "wrenching" it (no pun intended). If one were to over tighten and strip the threads, is the fork ruined? I recently raised my seat post and I know I tightened the clamp way higher than what the thru axle was tightened to.

shelbyfv

From your description, it should be much tighter than it was. In fact, I doubt you would strip it using a multi-tool. If you aren't confident, go by a shop, let them torque it with a wrench and get a sense what that feels like with your own tool.

frogman

what he said ! Good suggestion !

geepondy

Thanks. If I do, I should go to a different shop then the one that changed my tires, lol as it seemingly obviously was not torqued at all.. FYI, I'm using a regulars 6mm hex wrench, not a multi-tool.

FYI, what kind of grease should one use on the thru-axle? It seems like it's more of a petroleum jelly consistency.

cpach

TBH the torque on thru axles tends not be particularly sensitive. There are a lot of threads of engagment on most forks/frames and it's a pretty coarse thread. That said, if it didn't loosen on you, and the axle wasn't shifting at all, it was as tight as it probably needed to be. Modest force on a normal hand tool is honestly generally about right.

Grease on the thru axle is mostly to reduce the odds of corrosion. Any sort of sane, reasonable grease you would use on a bicycle will be fine applied lightly.

Barry2 

My first suggestion is buy a torque wrench. But failing that….

12NM is kinda abstract. I’ve never held a newton (fig excluded).
But 12NM = 8.8 foot pounds
8.8’lb is a number I can work with.

So you can extend your wrench to make it a foot long and hang 8.8lb off the end.
Or a 6” wrench and double the weight.

I would not expect you to do this every time, but once in a while to recalibrate your hand might be good.

I own a gun where the manufacturer provided wrench is the correct length so that the weight of the gun provides the correct torque.
Maybe you could use the weight of the bike with a correct length wrench to achieve the same.

Barry

Iride01 

So you are thinking that your thru-axle that wasn't giving you any problems needs to be tighter than it was so you have some difficulty next time you want to remove it?

I wouldn't try to judge how well something was tightened by how easy it is to loosen.

jp911

My personal technique is to use my multi-tool to install and remove thru-axles, checking with a torque wrench the first time I install, so that I have a good feel for what it will take if I need to get the wheel off to change a tire mid-ride. If you want a visual reference as to whether or not the axle is moving/loosening, you can use the mechanic's trick of marking the bolt head and frame with a paint pen (auto mechanic...usually race mechanic).

Calsun

With a 8 inch or shorter wrench it is difficult to apply more than 10 ft lbs of torque. Now with bike part manufacturers specifying the torque settings so a novice bike shop mechanic can not do damage, there is now a felt need to have a couple of torque wrenches available. Park Tools with their 6mm and 8mm hex wrenches for pedals and cranks the length of the handle prevents overtightening.

geepondy

I tightened it more than the bike shop but not what I think excessively. Using a regular 6" hex wrench, I would estimate I had another 1/8 to a 1/4 turn until it would require more than a modest effort to tighten further. I think I probably tightened my seatpost more. I was realizing, it's really just a bar to hold the hub which does the turning. I can't see how it's going to loosen up even if just modestly tightened.