Rear wheel with thru axle

[jimmy156]

Having never owned a bike with thru axles before and having only just having cause to remove the rear wheel, at the risk of sounding stupid... should the rear derailleur hanger be held on by more then the through axle?

I took the wheel of by bike today and the whole assembly came off with the rear wheel. Made it a pig to get it back on

Having looked, I reckon in missing a bolt (there isn’t one in the hole visible in the pic) Either it’s rattled loose or was never fitted... am I right on this



I’m assume the thru axle will hold everting in place okay and I can ride it until I get a replacement part?

[InitialDave]

There should be a countersunk screw in that hole, yes.

[jimmy156]

InitialDave said:

There should be a countersunk screw in that hole, yes.

Thanks, any thoughts on if it’s alright to be ridden without?

Is it likely to be a generic screw or something specific (like the mech hanger themselves)

[Darkslider]

jimmy156 said:

Thanks, any thoughts on if it’s alright to be ridden without?

Is it likely to be a generic screw or something specific (like the mech hanger themselves)

If I was designing that thered be a little locating tab/nub to stop the hanger rotating when the axle was tight, and the screw would just be to keep the whole lot together when the axle is removed. I'd guess you need an M5 countersunk Allen head bolt, need to be careful not to get one that's too long or it might foul on the cassette if it protrudes through the back of the hanger.

[InitialDave]

I'm not sure, I'd be amazed if it weren't just a generic metric thread though.

I'd probably ride it like that, it's unlikely the missing fastener does anything except stop the derailleur falling off with the wheel removed. I assume it seems all secure and properly aligned with the wheel in place?

[Piginapoke]

InitialDave said:

I'm not sure, I'd be amazed if it weren't just a generic metric thread though.

I'd probably ride it like that, it's unlikely the missing fastener does anything except stop the derailleur falling off with the wheel removed. I assume it seems all secure and properly aligned with the wheel in place?

I wouldn’t ride it, it’s a simple job to fix and any rear wheel change will be a right faff.

[jimmy156]

Darkslider said:

jimmy156 said:

Thanks, any thoughts on if it’s alright to be ridden without?

Is it likely to be a generic screw or something specific (like the mech hanger themselves)

If I was designing that thered be a little locating tab/nub to stop the hanger rotating when the axle was tight, and the screw would just be to keep the whole lot together when the axle is removed. I'd guess you need an M5 countersunk Allen head bolt, need to be careful not to get one that's too long or it might foul on the cassette if it protrudes through the back of the hanger.

I mean that’s pretty much what it’s like. As I say, I didn’t remove the bolt, so have been riding it for an unknown amount of time without it without any issues.

I road the bike up and down the road and went through the gears without a problem. I was a little surprised they we still indexed properly after the faff of getting it back together!

I am due to go for a ride on Sunday, I think I’ll see if the LBS have an appropriate bolt, but I think I’d be tempted to ride it even if not. The only thing would be if a get a rear puncture... it’s definitely a two person job to get the rear wheel back on as it takes someone holding the mech in place while the other slots the wheel in.

[Darkslider]

jimmy156 said:

Darkslider said:

jimmy156 said:

Thanks, any thoughts on if it’s alright to be ridden without?

Is it likely to be a generic screw or something specific (like the mech hanger themselves)

If I was designing that thered be a little locating tab/nub to stop the hanger rotating when the axle was tight, and the screw would just be to keep the whole lot together when the axle is removed. I'd guess you need an M5 countersunk Allen head bolt, need to be careful not to get one that's too long or it might foul on the cassette if it protrudes through the back of the hanger.

I mean that’s pretty much what it’s like. As I say, I didn’t remove the bolt, so have been riding it for an unknown amount of time without it without any issues.

I road the bike up and down the road and went through the gears without a problem. I was a little surprised they we still indexed properly after the faff of getting it back together!

I am due to go for a ride on Sunday, I think I’ll see if the LBS have an appropriate bolt, but I think I’d be tempted to ride it even if not. The only thing would be if a get a rear puncture... it’s definitely a two person job to get the rear wheel back on as it takes someone holding the mech in place while the other slots the wheel in.

Have you got a spare spd cleat bolt in your toolbox? You might be lucky and it's the right thread, proceed with caution though!

[jimmy156]

Darkslider said:

jimmy156 said:

Darkslider said:

jimmy156 said:

Thanks, any thoughts on if it’s alright to be ridden without?

Is it likely to be a generic screw or something specific (like the mech hanger themselves)

If I was designing that thered be a little locating tab/nub to stop the hanger rotating when the axle was tight, and the screw would just be to keep the whole lot together when the axle is removed. I'd guess you need an M5 countersunk Allen head bolt, need to be careful not to get one that's too long or it might foul on the cassette if it protrudes through the back of the hanger.

I mean that’s pretty much what it’s like. As I say, I didn’t remove the bolt, so have been riding it for an unknown amount of time without it without any issues.

I road the bike up and down the road and went through the gears without a problem. I was a little surprised they we still indexed properly after the faff of getting it back together!

I am due to go for a ride on Sunday, I think I’ll see if the LBS have an appropriate bolt, but I think I’d be tempted to ride it even if not. The only thing would be if a get a rear puncture... it’s definitely a two person job to get the rear wheel back on as it takes someone holding the mech in place while the other slots the wheel in.

Have you got a spare spd cleat bolt in your toolbox? You might be lucky and it's the right thread, proceed with caution though!

I did think that!!! Spare bolts I have are m5 (and M4 is needed) they are also too short to be of use!

lBS didn’t have a bolt of the correct size/thread and I don’t feel like doing loads of trial and error visiting different bike shops, particularly as we are in tier 4 here.

I will contact canyon on Monday through their live chat and check the spec of the bolt I need to order. Annoyingly they are currently not shipping to the uk! So will have to buy from somewhere else!

[IroningMan]

jimmy156 said:

I did think that!!! Spare bolts I have are m5 (and M4 is needed) they are also too short to be of use!

lBS didn’t have a bolt of the correct size/thread and I don’t feel like doing loads of trial and error visiting different bike shops, particularly as we are in tier 4 here.

I will contact canyon on Monday through their live chat and check the spec of the bolt I need to order. Annoyingly they are currently not shipping to the uk! So will have to buy from somewhere else!

Is there a fasteners shop/supplier locally? There won't be anything magic about the bolt. Somewhere like these guys: https://www.wentinfasteners.co.uk/

You might even find suitable in a B&Q or Halfords.

[jimmy156]

There is a really handy little diy shop, but they have a sign in their window saying they are waiting for a COVID test.

That supplier you linked to are currently not delivering to tier 4 areas...

But a quick google turned up pro-bolt, who seem to supply parts for motorbikes and they will sell single adonised bolts of pretty much and size and colour! Winner! I’ll order a few different sizes and pick the best fit!

[gazza285]

An anodised bolt would be aluminium? Fine for holding motorcycle fairings on, but not for anything serious.

I would get either BZP or stainless, liberally dosed with threadlock. they are ten a penny from a proper bolt shop, or eBay.

[jimmy156]

The note on the frame says a maximum torque of 1nm, so i assumed it didn't need to be super strong.

My thinking of aluminium over steel was that there would be no chance of rusting (or an kind of corrosion caused between the two types of metal bolt / frame)

I think it will probably be okay for this purpose (I have ordered them now ) the bolt really isn't doing anything much... I rode for 16km today (and possibly thousands before i knew it was missing) without it even there.

The maximum it needs to withstand is the weight of rear mech when the wheel is off.

Happy to be corrected if any engineers on here tell me I am wrong!

Edited by jimmy156 on Saturday 2nd January 20:28

[IroningMan]

gazza285 said:

An anodised bolt would be aluminium? Fine for holding motorcycle fairings on, but not for anything serious.

I would get either BZP or stainless, liberally dosed with threadlock. they are ten a penny from a proper bolt shop, or eBay.

The OP's pic suggests a tightening torque of 1nm - I don't like aluminium fasteners, but that should be survivable...

[gazza285]

Not for me, but it's not my bike.

[jimmy156]

A little googling suggests that people use aluminium bolts for this, and they are supplied as standard from some manufacturers, so should be fine. fingers crossed that either 15mm or 20mm long fits!

[Darkslider]

jimmy156 said:

A little googling suggests that people use aluminium bolts for this, and they are supplied as standard from some manufacturers, so should be fine. fingers crossed that either 15mm or 20mm long fits!

Looking at that you might find they're both too long, keep peeking at the back side as you're tightening it up to make sure it's not gone right through and is clamping your cassette lockring, hitting the smallest cog or otherwise bottoming out.

[gazza285]

Darkslider said:

Looking at that you might find they're both too long, keep peeking at the back side as you're tightening it up to make sure it's not gone right through and is clamping your cassette lockring, hitting the smallest cog or otherwise bottoming out.

Being aluminium, it will be easy to cut down...

And it is a sprocket, not a cog.

[jimmy156]

I think it maybe deceptive, the chap at the bike shop actually said they would need to be "quite long" he tried one that looked the length of a cleat bolt (so 10mm) and it didn't even reach the thread on the hanger. I see what you mean about going too far though. I won't know until i try it!

[Darkslider]

jimmy156 said:

I think it maybe deceptive, the chap at the bike shop actually said they would need to be "quite long" he tried one that looked the length of a cleat bolt (so 10mm) and it didn't even reach the thread on the hanger. I see what you mean about going too far though. I won't know until i try it!

Now you mention it it's got to go through the thickness of the dropout which could be 6-8mm itself so hopefully the 15 will do the trick