yes you do need longer bolts, they used to come with titainium chainringbolts IIRC - that's what mine look/feel like anyway. You simply put the rock ring on the outside of the big ring. They protect up to 50 tooth round chainrings.
From the logo I think the cranks are straight Deore ones from about 88/89 before the split to DX LX etc - They should have a date code stamped on the back along with a model number. I love them.
Hi!
The modification is due to the fact that these were originally sold as deore DX tandem cranks and would have been mounted on the opposite side to normal (for the stoker at the rear) hence the pedal threads being the opposite way round. The mod was carried out by a pro engineering company in the states and according to them is totally reliable (they have had no complaints in all the time they have been caryring this modification out). I had a full deore DX groupset on my 92/93 Diamond Back Apex and as far as I am aware DX cranks never said DX on them, just Deore. Hope this helps mate.
He's been trying to sell them for probably a year now. Every week, same auction, $37 BIN. Nothing. I really am impressed he hasn't given up.
They really are nice cranks, but they're not that special or rare. 60quid is way too much IMO. I if needed these for a project, and didn't mind the modification, then I would pay about 7quid.
Not trying to offend.. I'm just sayin
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