Shimano 7710 Crank and BB, question!

[vekter303]

Hello,

Looking for a bit of help with 7710 crank and BB.

First time I will be disassembling these, to replace the BB. I have some experience with builds and maintenance, but not with these specific parts...

So, while I could simply just try, I wanted to best informed before tackling the job. Can tell me what way the dust caps, lockring and bolt that secure the crank arms are threaded?

I have all the tools needed and have checked the Shimano manuals, the manual is pretty sparse and couldn't find a dealers manual. Nothing available online either for this specific crank and BB. I had guessed it would be against the direction of pedal rotation relative to each side - drive/non-drive, in order to loosen but in watching other fixed gear builds this doesn't always seem to be the case.

Cheers!

 

[raleighnut]

If it's a square taper BB then they're all normally threaded.

 

[vekter303]

Appreciate the reply!

It's Octalink, although the BB isn't any issue. I have a replacment and so can see how that is threaded.

More an issue with dust cap, bolt attaching the crank and lockring.

Cheers!

 

[raleighnut]

Appreciate the reply!

It's Octalink, although the BB isn't any issue. I have a replacment and so can see how that is threaded.

More an issue with dust cap, bolt attaching the crank and lockring.

Cheers!

The BB is diferentially* threaded but the retaining nut/bolt are not, as I understand it Octalink can be buggers to pull off. I don't have Octalink on any of my bikes but one has a Truvativ crank that has an 'Isis drive' BB (their version of a splined BB) and the guy who fitted that said they can be a beggar to get off.

* one side LH thread the other RH thread

 

[vekter303]

Great stuff, thanks for that...

Given past experience with pedals and freewheel sprocket, I supposed left handed thread to tighten was more common. I'm always impressed that people can hold all these quirks of bike tools and components in their heads. They can seem deliberately obscure sometimes!

 

[Gunk]

I’ve got a Dura Ace 7700 Octalink on one of my bikes, no hassle getting it on and off whatsoever and a really nicely engineered crankset. They’re only hard to remove if they’ve been assembled dry and over tightened.

 

[vekter303]

That's good to hear, shouldn't be any problem in that case.

I'm curious to hear, how have you found wear on the BB, assuming it's 7710 too? I do get the miles in on it, but I am a little suprised just how much play has developed in the crank/BB...

 

[Gunk]

That's good to hear, shouldn't be any problem in that case.

I'm curious to hear, how have you found wear on the BB, assuming it's 7710 too? I do get the miles in on it, but I am a little suprised just how much play has developed in the crank/BB...

Mine is mint, very little use

 

[vekter303]

Cool. Without evidence to the contrary - like say, reality - I will continue to believe it's a colossal amount of watts

 

[Big John]

From memory just use a big allen key on the crank bolt and it pulls the whole crank off. A really simple system for crank removal. I've not had octalink for years though. I hope I'm right lol.

 

[Gunk]

From memory just use a big allen key on the crank bolt and it pulls the whole crank off. A really simple system for crank removal. I've not had octalink for years though. I hope I'm right lol.

It does, it works as an extractor

 

[raleighnut]

Aah one of those is it.

 

[Gunk]

What is important is to torque both the BB and crankset to manufacturers spec, the BB is 50-70 Nm and the crankset is 35-50 Nm

Useful reference here

https://si.shimano.com/en/pdfs/dm/MDFC001/DM-MDFC001-06-ENG.pdf