Crank issues....

Large, powerful riders are usually harder on their equipment. The simple answer is to upgrade to higher quality crankset with better materials and stronger fasteners and perhaps a different type of mounting system.

The cheap fix might be something as simple as a $3 bottle of blue Loctite if it's simply a bolt that keeps working itself loose.

What brand/model crankset are you currently destroying and what is your maintenance intervals regarding checking the fastener torque?

They have been initially the standard that came on the bike. Since then I'm not sure just wherever I can get a diamond offset in a dog leg in the right length. I have tried superglue but it didn't work.

FWIW. Short of buying a new crankset, you can try the following...

• Clean out (wash with soap & hot water, dry) the wallowed out crank arm's taper ...
  

• Create a two-side shim from brass stock (or, a tin can if you have snips) ... round the edges with emery cloth or a file (this is a "safety" issue)
  
• TEST FIT over the BB's DRY taper ...
  

• Take some JB WELD (~£3 ... accept NO SUBSTITUTES) & apply to the affected area of the inside of the crank arm tape in place with some cellophane tape
  

[*] GREASE the BB's taper

• Install the crank arm carefully (the tape keeps the shim from moving during THIS phase)
  

• CUT a washer for the crank bolt from a milk jug cap ...
  

• SECURE ... but, not too tight, yet ...
  

After 24 hours, tighten the crank bolt ...

If the bolt uses an 8mm HEX KEY, then (instead of Loctite) place a piece of packing tape over it & across tha portion of the crank arm to keep the head from working loose in the future ...

If the bolt uses 15mm (?) socket wrench, then you want to find a crank arm "dust cover" to keep the bolt from working loose in the future.

BTW. I have mixed feelings about various BB & crankset combinations ... my preference is for the almost obsolete OCTALINK ... ISIS is a little dodgy AND almost obsolete, too ... the MegaExo/Hollowtech-II has advantages & disadvantages. There are other types, but I believe that THOSE are your alternaive options.

What Campybob said - get a small bottle of Loctite medium strength "blue" 242 threadlock. It'll cost a few quid but it's well worth it. It'll stop the bolt from working free and the progression from square hole to round hole will be stopped and it will also prevent corrosion.

Put the thread locker on the bolt and not the BB axle flats or the crank. 🙂 Even loctite superglue and loctite threadlocker are two completely different things.

The other part of the equation is mounting the cranks properly. Just make sure that the taper on the bottom bracket axle is clean and dry and that the "flats" on the inside of the crank that face the BB axle are clean too. Mount the cranks and tighten the bolt to the recommended specs. Shimano specs are 305-391 in/lb

parktool.comcrank installation and removal square spindle typeOpen ↗

Hope the link helps.

The alloys used on the mtb square taper cranks were quite unforgiving about torque errors. Even on my scant sized frame I still went through my share of them before going Octalink and later ISIS(A race prize so who's to complain). The issue is that there are only the 4 points to take all the pressure when there happens to be a little wiggle. If you were lucky enough to have it corrode in place, as many did so effectively, you stood a chance of keeping it there. If it gets loose once it is going to be a regular scheduled thing to torque check it, plus the items mentioned. If that sounds bothersome, it is. Fortunately there are a myriad of modern era replacements both new and Ebay for the flip side. There are positives to each and negatives to each, however any of the modern varieties would suit acceptably if the bolts were torqued properly and maintained as such.