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These are the pilots cranks off the tandem. Got to be 20 years old. Clearly there is some wear but there are no obvious ridges or grooves to create stress raisers and we are hardly stressing them with big jumps etc nowadays.
would you replace them?
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Problem is they are octalink and I think no longer available. can't use external BB cups 'cos of the eccentric so I would need to go to square taper so replace the two BBs as well
thoughts?
It's a solid crank? Wouldn't concern me at all.
hollowtech octalink
It wouldn't worry me unless the front of the crank has clearly been flattened and lost a bit of material... It's probably just the anodising that's worn off.
Ta
I might polish the rest of it.
I think a bit of material has gone but not much
I've had external BB on an eccentric BB.
I'd just polish them, no grooves or ridges so can't see the issue.
Also wondering why you can't fit ht2 or similar to the eccentric, have had eccentrics on singular swift and charge cooker?
I think the cups would cover the screw for the taper wedge. Maybe not. a set of external BB tandem cranks are a huge amount of money as well
Hols2 - not tandem cranks tho are they? Tandem cranks you need 4. two lefts with spiders and one right with a spider and one right with no spider!
£500+
So, can you buy three regular cranksets and have two of the RH cranks (with spiders) helicoiled to take LH pedals?
And cut a spider off one right hand crank?
Oh, and helicoil one of the LH cranks to take a RH pedal.
Either polish them or paint them black. Either way I wouldn't replace them just yet
They don’t need replacing 🙂
Well if it breaks the stoker has to pedal you home. So the answer entirely depends on which you are.😊
No but I might rethink my cleat position
1. I wouldn't be changing those.
2. You can still get octalink BB.
3. I have a v similar looking ebb and fitted HT2 (external bottom bracket).
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Possibly daft for reasons I've not considered or teaching you to suck eggs, but I'm sure I've seen Tandems with two normal chainsets? They just run a set of double chain rings at the back (granny and middle) then a couple of DH chainrings in the outer position from pilot to stoker?
I think an external BB would fit that fine, could make an interesting experiment to see if they really don't last as long as cartridge BB's!
Hols2 – not tandem cranks tho are they? Tandem cranks you need 4. two lefts with spiders and one right with a spider and one right with no spider!
£500+
Can’t you just by the one chainset with tandem bits from spa cycles looks about thirty quid without rings and bb?
https://www.spacycles.co.uk/m2b0s109p3951/SPA-CYCLES-TD-2-Tandem-Left-Hand-Crossover-Crank
Obviously tandem chainsets are a mystery so I could be talking guff!
One sided drive is possible but I could not get a decent chainline when I tried to do it
I have a very similar EBB shell, External BB actually have a very small 'lip', I reckon one would fit.