I am ham fisted so want to replace the hex pinch bolts in my non-drive side crankarm with torx.

I have found some but the thread pitch looks different, is this likely to cause a problem? My instinct says yes.

is this likely to cause a problem?

nothing moar torque won’t cure 😉

but generally yes.

I’d stick with hex and invest in a decent torque wrench and some quality hex bits to go with it.

If your asking this question do not use the wrong pitch – you risk wreaking the arm.

You’ll just strip the thread on the crank. DON’T DO IT.

They’ll just be a standard M thread I’d have thought, get thee to screwfix!

You’ll wreck the threads, but apart from that, it’ll be fine…

I am ham fisted so want to replace the hex pinch bolts in my non-drive side crankarm with torx.

Gxp cranks, one bolt, do it tight forget and ride. Much prefer them for fitting, removal and general use. No hassle with pre load, even tension or any of that.

Yeah and buy a santa cruz to put them on, too. Great advice Mike.

Bolts are sized by diameter and pitch. If it’s the wrong pitch, it’s the wrong bolt.

I thank you all m’learned forumista’s

sounds great mike – until that one bolt extraction system cap strips and the cranks stayed put….. It works well on bikes that are well looked after…. the bikes that the bike shop sees only when its broken. not so much. I HATE THEM !

Gxp cranks, one bolt, do it tight forget and ride. Much prefer them for fitting, removal and general use. No hassle with pre load, even tension or any of that.

one pair that came on a bike loosened off and ended up in the bin as they lunched their splines. another pair, again fitted to a pre-assembled bike, killed it’s BB in about 6 weeks.
utter crap i’d never go near again.
i do, however, ride a santa cruz.

Er I fit them to my santa Cruz… Is that an extra bit of hate going on there? Just see them working well with less of the issues. Hope bb for 3 years seamless life, might grease it next year…

😆

No just pointing out that the OP wanted advice on two 50p bolts, not a critique of his component choice

The best solution isn’t always the answer to the question being asked. It was more a long term thought.

the best long term solution never involves sram though 😉

Indeed, I know of no one who has owned and used shimano cranks for more than 5 minutes without them exploding and showering orphans in liquid hot metal and shrapnel.

and in the same spirit – OP – you need to take a look at the potential for your pension fund and the yield from purchasing an annuity, this could be vital when selecting cable inners in 2035.

Just to expand slightly (since the main question has been answered)

1) don’t replace perfectly good hex with annoying torx
2) M6 in biking is almost always the coarse thread, 1mm. There is a .75 fine pitch but I can’t remember ever seeing one of these on a bike. This doesn’t constitute “just fire it in” though but should make finding bolts fairly easy usualyl
3) If in doubt, find a nut the same size, spin it onto the old bolt and then try it on the new.

Oh and 4, don’t buy SRAM cranks. The arms are actually OK but the BBs are mince so you’ll end up fannying around and wasting money and eventually buying a Hope or similiar replacement. This isn’t a terrible outcome, but amounts to doing deals with terrorists.

Gxp cranks, one bolt, do it tight forget and ride. Much prefer them for fitting, removal and general use. No hassle with pre load, even tension or any of that.

And it’s a good job as your BB will last about 2 rides.

since we’re expanding around the original question…

2) M6 in biking is almost always the coarse thread

Almost all bolts in common usage use the coarse thread. If an item does not explicitly state the thread pitch, it is very likely to be coarse thread.

And anyway, the M6 pinch bolts on HT2 cranks – don’t they have a slightly smaller diameter head? I’m sure I’ve tried to replace on before that was a bit rounded and gave up.

It’s Shimano – the bolts are *bound* to have some sort of proprietary quality that means they can charge a fiver a pair for replacements 🙂

It’s Shimano – the bolts are *bound* to have some sort of proprietary quality that means they can charge a fiver a pair for replacements

i think the heads are smaller than standard.

i think the heads are smaller than standard.

Echo, echo, echo, echo, echo…………….echo.

Surely the ultimate solution to this problem is square taper.

That way installation errors can mess up both the taper in the crank and the BB, the BB won’t last as long as decent HT2 BB’s, it’ll weigh a lot more and you’ll bend it going off the first drop if the arm doesn’t shear off.

But at least you’ll win internet arguments because despite the fact no one uses them any more, for some reason everyone thinks they’re great, they just don’t use them themselves……..

And anyway, the M6 pinch bolts on HT2 cranks – don’t they have a slightly smaller diameter head? I’m sure I’ve tried to replace on before that was a bit rounded and gave up.

They have a tapered head otherwise as you tighten it butts up against the wall of the recess.

OP, forget the torx bolts. The fault lies in your tools and hamfisted work as per your previous thread.

Gxp cranks, one bolt, do it tight forget and ride. Much prefer them for fitting, removal and general use. No hassle with pre load, even tension or any of that.

Yes, that works fine until one day the bolt snaps and you have to cut the cranks off! And the bottom bracket lasted literally hours of riding before I had to replace it with a Hope (which is still going strong 5 years later).

OP, forget the torx bolts. The fault lies in your tools and hamfisted work as per your previous thread.

This is the nub of the issue, those bolts are fairly lightly torqued;
1) how on earth did you manage to mangle them?
2) how on earth did they not strip out of the alloy threads before the hex key gave up?

Torx is actually pretty rubbish, you’ll bend the splines on a torx key long before you round off a hex head/key. 90% of the time it’s used on plastic bits (and for some reason, mountain bike brakes)

What’s the worst that could happen?

Oh.

thisisnotaspoon – Member

1) how on earth did you manage to mangle them?

Bad tool, or bolt head full of mud, most likely. (incidentally, fixers-of-other-people’s-****ups-everywhere- if you do get a stripped socket cap bolt on a mountain bike, before you do anything else, see what happens when you clean the mud out- often it’s only the top that’s stripped, because the owner’s tool only touched the first couple of mm, and you can still get adequate engagement).

Link to previous thread anyone?

thisisnotaspoon – Member

90% of the time it’s used on plastic bits (and for some reason, mountain bike brakes)

****ing bastarding mondeo rear wheel bearings, is all I can say to that. T45, special long shaft tool, engaging into a bolt made of rust which has basically welded itself to the hub.

There’s another **** of a torx in a focus front hub IIRC, it can **** off too. It’s like everywhere they found a bolt that was totally exposed to road salt, which you’d only want to remove after 75000 miles, they used a torx. It’s because of that thing I said about Henry Ford’s mum.

i aint got an issue with torx … ive not had any difficulty removing any…including those holding the rear side seats into the boot of a 1990s land rover discovery……

Most of the time when i see folks having issues with them its because there using some tool they got in an xmascracker/ikea furniture package or free with their avid brakes……

Get some wera torx plus keys you wont look back.

I’m eternally perplexed with how ford’s are put together, take the OH’s fiesta’s air filter.

1) undo 2 fair sized bolts on the top, they’re huge, but do nothing except loosely hold the plastic airbox in place.

2) figure out how the **** your supposed to undo the two hard to reach rubber coated dome headed nuts inside rubber grommets so they doesn’t spin, on the back. Realize that many before have probably tried and actually they now just pull out as they’re broken.

3) dismantle air box, it’s held to together by torx headed screws, about 12 of them.

Who designs this stuff, seriously, 3 screws would have done it. There’s even a nice big empty bit of engine bay you could put the airbox in.

Hyundai’s aren’t much better. Daughter needs the sidelight bulb replacing on her I20, got to take the whole headlight unit out (and undo bits of the grill and bumper) as there’s no space to get your hand in to just remove the bulb!

I long for the days of working on a Mk3 Cortina!

There’s even a nice big empty bit of engine bay you could put the airbox in.

Only in your model. I would guess (actually, it’s more than a guess) that in many other versions of the car (that use the same airbox) that the “empty space” is full of hardware, most of which will take priority over an airbox…..

Update for you all. Having taken on board your comments, I’ve bought an Effetto torque wrench and promise to unwind it when I’ve finished using it.

I may also buy better hex fittings for said torque wrench, what do you all recommend?

sealey premier have stood me well for a few years if its 1/4″ you need – which i hope it is for bike use….

This may have been answered but why torqs?

You can transmit more torque through a torx headed bolt before failure of the head.

So you can either go to a smaller fastener, or a softer/lighter material.

unless your tinas apparently :D:D:D

Torx is actually pretty rubbish, you’ll bend the splines on a torx key long before you round off a hex head/key

Although i know where hes coming from as most folk dont own decent torx and a shit torx is more damaging than a shit hex key.

Any numbers to back up torqs being better? Never been able to find any myself but happy to be shown.

One of the advantages of Torx is that the contact angle means that more of the force used to turn the bolt goes into actually turning it, rather than acting radially.

Wiki explains it quite well….

https://en.wikipedia.org/wiki/Torx

Where I work we have some fasteners that undergo high temperatures (several hundred degrees) and quite a lot of thermal cycling. They tend to bind & become hard to remove, which causes breakages, damage & issues during maintenance.
A while ago we swapped to Torx headed fasteners in these locations & now have much less reports of issues getting these fasteners undone.

Torx are a better bet than hex due to less chances of rounding or cam out of the head.
The usual issue with Torx is someone choosing the wrong size bit for the bolt in question and ending up damaging the head of the bolt. With MTBs the chances of there being dirt in the bolt head are quite high and if this isn’t removed then proper engagement will not occur and likely damage to the head will result.
As for bits, personally I’d recommend Wiha or Hazet bits. If it’s torx keys then Wiha or Bondhus would be good. If you’re pockets are deep enough then PB Swiss get high praise but I have no personal experience of these.

don’t replace perfectly good hex with annoying torx

As someone who frequently undoes and retightens these bolts on my Stages, I can tell you that the inboard one is in quite a fiddly position and that this with the particular combination of shallowness and cheese consistancy has led to me have to reach for the drill.

The reccomended torque is 12-14. I for one would prefer torx.