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Hmm, I’m in a pickle! Not sure how, as it’s been off several times, but I’ve managed to round off the main crank bolt on my SRAM GX cranks! The one that needs 50nm to undo!
someone suggested trying to access from the non drive side but that doesn’t work so I need expert help I think!
I'd remove the extraction cap so you're only trying to get the bolt out. Drown it in plusgas and then hammer the biggest torx driver bit you can in the knackered bolt.
Good luck!
How does the cap come off? That’s the first bit of knowledge - didn’t know it did 😂
You can use the four holes unscrewing as a LH thread.
See last page
Weld an Allen key to it carefully (if you have access to welder) assuming it's steel.
If not perhaps try JB Welding (epoxy resin) Allen key into rounded hole
Don't forget to swear a lot
I did this . Hamfisted tightening stripped the thread on the bolt / crank.
knew the whole thing was toast as its not really fixable. Looked at removing the cap and couldnt get that to shift so eventually I used a hole saw to remover the cap from the crank . Cant recall what size it was but had to carefully position the centering bit to stop it dancing till it scored a grooove allowing the centering bit to be removed.
and then hammer the biggest torx driver bit you can in the knackered bolt.
Good luck with that. It can work with a bolt that's not too tight but I completely mashed the head of a crank pinch bolt done up to 14Nm using this approach, at 50Nm (albeit a larger bolt) I think you're going to struggle although maybe there's nothing to loose.
Do you know how long a bolt it is? I think I'd be looking at trying to drill it out. It can be a slow laborious process but may get the bolt out without damaging the cranks or BB.
Good luck!
-- Edit --
A quick Google suggests that the bolt isn't that long & possibly aluminium rather than steel both of which are useful traits if you decide on drilling it out.
If you get fed up I’d remove the pre tensioner and the saw through the axle. It’s aluminium.
You might as well try the drilling the bolt first. But as anyone who has removed these cranks knows the threads will need to be good to get the cranks off
Actually, the length of the bolt's irrelevant as you're just drilling the head off. You'd still need to unwind the shaft from the threads but it won't be under any tension once the head's off.
Can you get a reverse thread extractor big enough? That some plusgas and a proper long breaker bar would be my approach
I now have a 1m breaker bar just for sram cranksets
Try the following
Order a new crank bolt.
Remove the extractor cap & use one of these These to remove the bolt.
Reinstall bolt & extractor cap.
Thanks everyone - it’s a task for later today so I shall follow the advice and update!
I think you might get away with packing the gap with tin foil or paper. Wrap the allen head in tin foil to sapce it out , or try decent weight paper as the packer .
Can work , and iver seen paper clips being used on the corners as well , just takes up a tiny space and allows enough torque to break the nut loose
I now have a 1m breaker bar just for sram cranksets
I already had one, but just had to use it for the first time yesterday on a SRAM Crank Bolt myself!!! Absolutely staggered at just how bad a design this is, but also just how every manufacturer seems to put everything together dry too in the understanding it will all cold weld itself together, but at least it's not gonna fall off...
I had to use the 1m breaker bar, with my not insubstantial weight leaning on it (and the crank arm tied to the chainstay with an entire 700c inner tube wrapped around and around it and the GF holding it all steady and leaning on it too... This was AFTER I'd had a go at getting it off with my 300Nm Makita impact wrench, which did sweet FA!!!
Absolutely staggered at just how bad a design this is,
Yep, but there are ghetto work rounds, this one works every time......
And I fancy PhilH's hex extractors for OP.....
https://youtube.com/shorts/spQLj_vf8Ss?si=r-dczalT4Cy6-0Qt
I’ve bought the hex extractors on Amazon, delivery due this evening - we shall see! I got the cap off so that’s a start…
the suspense is killing me.....
Ha sorry - fighting with it right now, shall update soon…
Not going well - the hex extractor doesn’t seem to work - it’s not biting the bolt and just spinning like the original Allen key. The annoyance is rising, I can see me wielding power tools soon!
Left handed drill might get it out. I have had success on a similar arrangement in the past somone else had tried an extractor on, by drilling it out, tapping a thread in it, then fitting a bolt with a nut on it. Tighten the nut down to lock the bolt in place, then undo the bolt, taking the offender out with it.
Good luck.
F***! So as expected I’ve gone through the swearing frustrated phase into giving up for the night - I’m in ‘destroy it all!’ mode! The bolt will not let go, still… Time to breathe and try some more tomorrow evening! I am close to just cutting through the axle out of frustration, and it’s pretty likely I’ve damaged the axle threads anyway 😡😩
So suspect that you need to go big w the extractor, maybe drilling out a bit so a bigger one can get purchase.....
Ultimately/realistically the axle and cranks are toasty, so cut (ha) your losses and do what you need to do
Ooft. As above it’s a crap design. I choose shimano whenever I can now but sram is oe on most bikes
Assuming the bolt is steel, weld a hex head bolt to it so that you can get a socket on.
The heat will help break the bond
It’s (was!) an aluminium bolt - there’s not much left of it now, but it still won’t let go. I don’t have access to a welder anyway, but thanks for the help…
At this point I think I'd be drilling it out, you'll want a bit that the same diameter as the bolt shaft. Once the head's gone (and assuming that the bolt's not seized) you should be able to unwind the shaft.
The axle threads may well be fine.
If you end up trashing everything & need to replace, Merlin might be worth a look (depending on your needs).
https://www.merlincycles.com/shimano-slx-m7100-crankset-with-chainring-12-speed-180723.html
It’s probably a bit late now, and I’m not sure about it as a solution on ‘lightweight” materials and at that torque level, but in my good ole motorbike days
- with a sharp centre punch or small sharp chisel, hammer an indent into the outside of the bolt , once the indent is created use a blunt punch/screwdriver etc to punch the bolt in the undo direction. (So shape the indent accordingly and in a nice place to make the first few blows easy) , I’d also try soaking it in plus gas or another penetrating oil before.
so I need expert help I think!
Take the bike to local bike shop, hand over your credit card and walk away quickly before you hear anything from the workshop. Go back later to retrieve bike. Works every time for me.
I’ve ended up ordering a new crankset from Merlin, accepting that it’s officially knackered! Now I can attack the axle to get it out!
@nickc Whilst occasionally I do that, although not a mechanic, I do like to do most of the work myself if I can! This has beaten me and I thought it might, but all is left is to get the bar steward off! Thanks everyone for reading and helping!
Last time I had stuck cranks I just accepted the inevitable and cut them off with an angle grinder.
Yep, same here, I try to do as much as I can, but after a while, you have to admit defeat before you do something stupid and permanently break something - and let some-one else (who has probably seen this before) do it for you.
The SRAM bolt is a dumb design, and even with the 'right' tools, like others on here, I've a 1m breaker bar just for this job, it's not something I look forward to do. I'm hoping the SRAM crank will break so I can replace with Shimano, but after 8 years, the bloody thing keep on working. I think it's doing it to spite me.
Different type of crank, but going at them with an angle grinder was almost therapeutic.
I'm actually replacing the crank arm bolts on both my Hollowtech cranks this week with these Jtek jobs because there's one on each feeling like they're rounding out, and that's a whole world of pain I don't want to enter.
I'm actually replacing the crank arm bolts on both my Hollowtech cranks this week with these Jtek jobs because there's one on each feeling like they're rounding out, and that's a whole world of pain I don't want to enter.
Bookmarked those!
Nice one. Assume you removed the junky plastic preload and just attached with a hacksaw?
@munkyboy yes, exactly that - unscrewed the preload ring, peeled it off (easily!) then got the hacksaw on it. Went through it very easily!
A length of M10 stud and a couple of nyloc nuts and you could be back in business 😀
Well it’s off! Took the nuclear option and got the hacksaw out! Thanks for all the advice, hopefully installation of shiny new parts will be simpler!
I'm glad that's sorted.
Do not under any circumstances be tempted to have one last go at the bolt "for experience". It will immediately come loose leaving perfect threads for immediate reuse 😆
Obviously far too late for these cranks, but I’ve always put copper slip grease on the threads of both gxp and dub crank bolts and never had an issue. Given the torque you always need a big ish lever (I use an old Lidl torque wrench that’s really long that I replaced with something more accurate), but always come off ok for me so far. Just foot on the pedal and lean weight on the torque wrench.
@joebristol Good advice - this surprised me as these cranks have been on and off a few times (quel surprise- the BB needed replacing a few times) and it's always been ok. I too have a long breaker bar just for this job, but this time the bolt just rounded off in one go and became unrecoverable. I've gone for a different extractor bolt solution this time - an 'ejector cap'. We shall see how it works on the new cranks (if I can get the extractor bolt off the new cranks when they arrive!!!)
Oak Components | Crank Ejecter Cap Set fits SRAM DUB & OAK | M18/M30LH – Cykel House
Well it’s off! Took the nuclear option and got the hacksaw out! Thanks for all the advice, hopefully installation of shiny new parts will be simpler!
I'm instantly curious as to how tightly your pedals are attached.
Not to 50Mn, that's for sure! They came off no bother at all - hope that satisfies your curiosity... 😎
