Try as I might and even with the right tools for the job I still managed to round off the alloy bolt holding my cranks on. 54nm my arsenal, the crank bolt is way tighter than that.
So its time to get the drill out and take the head off the bolt and try a puller to get the crank off. Has anyone else done this sort of job and have any tips?
Is it this crank?
And you've rounded the 10mm socket bolt?
Not those exact ones @linusr, mine have an 8mm torx bolt. Careful with yours as I thought mine was a 10mm allen bolt as it seemed to fit ok but then I checked and found it was a torx.
If you can find a big enough step drill it will at least stay central. If it's anything like the race Face next cranks on my bike the cranks will come off fairly easily once you have the bolt undone/beheaded.
Have you got a replacement bolt yet? It could inform your drilling depth.
Good luck
The good news is that you won't need a puller as it is not a press fit. The bad news is that the "bolt" you have rounded off is not a bolt but an internal plug with a thread on the outside, and cap which fits within the self-extractor piece around it. See this photo (assuming I have the right crank...)
You are probably going to trash the crankset...
Does the bolt look like this? https://www.sjscycles.co.uk/chainsets/truvativ-crank-arm-bolt-m18-m30-alloy-selfextracting-bb30-right/
Its 1his one:
href="https://www.sjscycles.co.uk/chainsets/sram-dub-crank-arm-bolt-kit-m18-m30-self-extracting-gold/
You will need a high speed steel drill the same width as the external diameter of the threaded part of the bolt. Drilling it out will trash the crankset. Protect your bike frame with cardboard, pillows, duvet. Get a mate to hold it down on the ground and get a new HSS drill and drill it to the depth as @OldNick says above. Wear goggles. Use the right drill bit. somthing like this drill bit Get a couple. Expect to break one... Take all my advice with a pinch of salt. I haven't done anything like this for a while. Some peer review on this forum will help.
Before getting the drill out , if your cranks have a hex bolt on the other side to the damaged one that says “ do not disassemble “ you can undo that side and pull off that arm
Hopefully it won't end up like the end of this thread...
https://singletrackworld.com/forum/topic/sram-crank-removal-fiasco/page/2/
I'm just going to try and take the head off the bolt then use a needle file on the inside of the bolt to make some grooves that hopefully will weaken the bolt. Then use a small chisel and tap it into the grooves. Hopefully this will break up the bolt. The bolt is only alloy it might work.
Before drilling, try tapping the next size up allen/torx head in, failing that try tapping the appropriate size chisel in and some good pipe grips on the chisel.
Drilling would be a last resort on something as expensive as xx1!
@plop-pants if you drill the head off, it is all that is holding it together. You can then gently tap the bolt and the shaft out of the BB - I think. It should not be very tight.
@oldnick, I've got a new bolt coming so will be able to use that to gauge drill size and drilling depth. I'm going to take it very easy but the bolt is definitely alloy so all should be fine. I'll report back 😁
I had to do it with a gx1 crank - the bolt was made of Wensleydale. I was binning the cranks, though, as I'd got so pissed off with them, so I could afford to be brutal.
Even being careful, I reckon a max of 10 minutes with a normal HSS drill bit will have the head off. Not sure about extracting the stub, though, I didn't need to for obvious reasons.
8mm torx bolt.
Are you saying the extraction bolt was a torn head? I’ve had loads of SRAM cranks on various bikes and they’ve always been hex head bolts.
Whichever it is, have you tried hammering a larger torx or hex socket into the butchered one and see if it’ll bite when you try to loosen it?
I was told it was a torx fitting but I've just had a closer look at the self extractor cap and it says 8mm hex! Ah well, its chewed up and rounded now. I could try tapping a larger hex key in but the bolt wouldn't budge using a 2ft scaffold pole on the crank arm and the same length bar and socket on the bolt before it stripped.
Can you a)remove the cover that the bolt pushes against so that you can get some penetrating spray directly onto the threads and leave for a day at least or longer if poss. Then refit the cover. B)I’d also go for a larger size torx key which you hammer into the bolt (not a hex that won’t work). At that size you could probably use a large impact torx, which means it will be more robust and you can really hammer it in. Then when you come to try and remove, don’t just whack max power on it straight away but work it back and forwards. It may seem counter intuitive but you can crack the seal more easily sometimes by trying to tighten rather than loosen the bolt. Back and forth a few times - take it steady gently increasing pressure each time is the way to go.
I’d try all of the above before drilling. Drilling stuff out by hand only ever ends messily for me...
Also a 2 foot scaffold pole is not really that big, I have a 5 foot Stilson in the garage, but I don’t use it on my bikes 😀
Right I’ve just popped out and recovered my impact torx bits. The bolt below is GXP but still 8mm hex which is what matters. T50 should do the job perfectly, or if you’ve really seriously mashed it try a 55 after you’ve drilled/ filed a bit more to get it to fit. Be amazed if that doesn’t shift it.
[url= https://i.postimg.cc/gJzDqgTC/106-AC770-2-A90-4-DEC-BB4-B-38-FA8-A3-D5198.jp g" target="_blank">https://i.postimg.cc/gJzDqgTC/106-AC770-2-A90-4-DEC-BB4-B-38-FA8-A3-D5198.jp g"/> [/img][/url]
[url= https://i.postimg.cc/1tvKWpxf/DFA982-F8-C67-B-4472-8-AD3-BDB460-FBB70-F.jp g" target="_blank">https://i.postimg.cc/1tvKWpxf/DFA982-F8-C67-B-4472-8-AD3-BDB460-FBB70-F.jp g"/> [/img][/url]
Ooh serious stuff there @timbog160. What do you use on the tool to turn the bolt?
Rather than use a drill bit I was thinking of using a rotary grinding bit. Hopefully a bit gentler and easier to use.
It’s a half inch socket so just takes any ratchet or breaker bar. If you don’t want to buy a whole set you can get the bit on its own for less than a tenner, but I guess you run the risk of it not fitting. Or you can borrow it but you’d need to be near Huddersfield 😀
I've got this to come with a nice X01 dub crankset that is only a few rides old yet clunks going past top centre on the drive side.
After messing with a 4 foot bar I have bought an impact driver and an impact bit set and hopefully that will sort it.
Plop, if you're near the midlands you're welcome to make a visit and see if we can get yours free.
Blimey what a nightmare.
Good luck op!
Thanks for the offers of help! I'm in tier 3 Kent sadly.
^^ Ditto to on the Kent thing.😟
Any of these should do it and are all that Sram cranks or indeed any Sram components deserve.
https://www.powertoolworld.co.uk/brands/makita/makita-grinders-polishers/makita-angle-grinders
This is why I stopped buying sram carbon cranks
I’ve had it on the original xx1 as pictured near the top, sram descendant carbon, x01 carbon and even under torquing it too around 40nm it still seized on.... I even had it on a emergency set of gx alloy ones that were only on for 2 rides!! Infuriating and down right dangerous when you try to remove them, the amount of force is required is ridiculous
That said I’ve never had them use a torx bit every single set has been 8mm hex
Best way I found was as long as possible 8mm and clipped into the pedal drive side and use that leverage of your foot to go the other way
Needless to say I’m now on shimano cranks and will never go back
Why don't you drill in slightly and then use one of those left hand thread self tapper extraction thinggymejobs. It's the sort of thing I'd use on my classic bikes. As you drill in, possibly with a hammer drill [though I' try without first] it bites in and undoes the centre of the bolt
It was a consideration but after trying several times with bars etc I'm worried I'm putting a lot of strain on the carbon frame. Besides that seeing nothing else has budged it I don't think my drill will come off well or ill end up flying around the garage looney tunes style. I'm going to used a dremel stone bit and take the head of the bolt. Hopefully I can then remove the cranks and get to work getting the rest of the bolt out of the axle. Failing that I'll be buying some shimano ones.
@plop-pants you're right. If you couldn't get the bolt out with all that leverage, then you will have no chance with an extractor tool. A stone bit will probably clog with aluminium - I doubt you will get very far unless you drill it with an 18mm bit. Paraffin is the best fluid to use when drilling aluminium with a HS Steel bit. Failing that just drill it dry. But as long as you have someone holding the frame and opposite crank arm steady (and lots padding on the frame) you should be ok with the drill. High speed, steady grip with both hands and try to keep it perpendicular to the bolt.
Thanks @linusr, I've got half a dozen sacrificial stone bits lined up so will see how they go first but i have a new drill bit ready too. Just waiting for the new bolt to arrive so I can get some measurements off it beforehand.
I was thinking about doing that 😁
In case its helpful, I've just been in aldi and they had a bewildering range of drill bits and disc attachments for wreaking destruction on stuck stuff. Some of them scary looking.
If you've got a Dremmel I recommend using one of the deburring heads if you have one as the stones, as mentioned above, will clog very quickly and become useless. A bit of WD40 will work as lubricant if there's nothing better to hand. I actually use it at work with great success when tapping Alu Bronze.
Thanks @swavis, they look a bit more capable. I guess tungsten carbide rather than HSS?
Yep, definitely the way to go. Just take your time and periodically use the hoover to remove all the swarf 👍
Well, I did it! I used a cylindrical rasp drill bit which took the bolt head off cleanly. I then tried using a puller to get the crank off but was finding it difficult to centre it so I started drilling into the decapitated bolt to provide a better seat for the puller head and noticed the bolt turned. I reversed the drill and it undid the bolt easily! Maybe the heat from the drilling softened whatever substance they put on these bolts. I put the new bolt in with the extractor cap too and was able to then take the cranks off. Happy days!
Well done! Very satisfying when it works. Now you need to crack that bolt every 6 weeks to stop it happening again!
As the bolt came out easily it suggests there wasn't any thread lock, perhaps it was just torqued way too tight.
It might sound counter intuitive but a bit of thread lock can* prevent it working its self too tight.
*might, possibly but not always
Thread lock does work to prevent bolts seizing - the bolt is unlikely to have been overtorqued - more likely a chemical reaction was holding it in place. Thread lock creates a barrier to minimise the chance of this happening. That’s why you should always use it on cleats too. This is also why a stuck bolt can sometimes be shocked loose by slightly tightening it rather than just loosening it..
Now you need to crack that bolt every 6 weeks to stop it happening again!
Good advice that. I've just loosened and re-tightened mine after 300 miles. It was flippin' tight!
I've set a reminder on Pro Bike Garage.
Nicely done OP 👍
It is indeed very satisfying when it all works out well 🙂
Might not make any difference but I fitted the ti nitride coated version of the bolt. Here's hoping!
good, now chuck the POS in a bin and fit some Shimano.
good, now chuck the POS in a bin and fit some Shimano.
You mean XTR ones? Plenty more expensive and also heavier?
Just stick to using the correct tools and this is unlikely to happen again.
Now you need to crack that bolt every 6 weeks to stop it happening again!
I’ve seen quite a few and have had two sram crank bolts of my own shear off. Cranks been on and off multiple times. It’s an aluminium bolt and at 55nm, it’s asking a lot from it.
SRAM gxp bbs are awful, press fit ones marginally better strangely! Quite why a stepped axle was necessary is bizarre and dub, well that can get in the bin. Shimano cranks on both bikes now, no cinching bolts down with the big torque wrench.
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Free Membergood, now chuck the POS in a bin and fit some Shimano.
You mean XTR ones? Plenty more expensive and also heavier?
Just stick to using the correct tools and this is unlikely to happen again.
So totally bypassing my post, previous page stating I’ve had everything from gx to xx1 both gxp and dub and they have all done the same, regardless of what you put on them or how long they’ve been on! It’s clearly a terrible design
They seem to a good job of torquing themselves up to, and beyond, 55nm themselves.
When I installed mine I did them up tight but without a torque wrench / breaker bar / combining my weight and gravity etc.
They certainly felt a lot tighter coming off then they did going on!
I've got a power meter "spider" on mine so I'd prefer to retain the SRAM cranks and manage this quirk by regular slackening off and re-tightening.
So totally bypassing my post, previous page stating I’ve had everything from gx to xx1 both gxp and dub and they have all done the same, regardless of what you put on them or how long they’ve been on! It’s clearly a terrible design
OK, but to counter your anecdote with anecdote, I have GXP cranks on two of my bikes (XX1 and X01) and both are fine. The set that I've had longest have been taken off the bike perhaps 5 times in 5 years (to change chainrings or BB) and I've not run into problems with getting them on or off.
Whenever people suggest preventative maintenance on high torque deformable interfaces (in this case with Alu bolts)it makes me squirm. I'm not sure the interface on any press-fit cranks (Shimano included) is made to be reassembled 10 times a year. It seems like a hassle that might shorten the lifespan of cranks, not extend it. IANAME 🙂
Aaand this is why i never use sram products.
Aaand this is why i never use sram products.
The cassettes, mechs and shifters are really good in my opinion.
The cranksets are best consigned to landfill.
Sorry @linusr, I did think about it but I had my hands full doing this job. Besides that the screeching from the drill and my boring commentary wouldn't have made exciting watching. It took me half an hour in a loop of drilling and measuring to get the head off. I do wonder if I'd just poked the end of a hot solder iron into the bolt for a minute or two that it might have softened the lock tight on the bolt and made removing easy.
Thanks for your help though!
Once the heads off the loads of the threads which is why its loose.