Singlespeed & Fixed Gear - DA cranks 7701 vs 7710, what's the diff?

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PDA
Renz
05-08-06, 11:40 AM
As I understand the 7701 is for road, while the 7710 is for track, but on a fixed gear can the 7701 serve just as well as the 7710? I can't tell any structural differences, chainline issues maybe? Is the 7710 supposed to be stiffer? Please enlighten me.

baxtefer
05-08-06, 11:59 AM
7701=road double
7710=track

The problem is chainline. The 7701's are a road double which have a "chainline" of ~43mm measured *between* the two rings. The inner ring is at ~39mm and the outer is at ~45mm. The 7710's will have a "proper" 42mm chainline. And since the 7701's are Octalink there's no way to dial in the chainline with a different length Bottom bracket spindle, since 109.5 mm is the shortest one available
Renz
05-08-06, 12:06 PM
Thanks baxtefer, that makes sense, but I still don't understand why the 7710 cranks would be almost double the price of the 7701, is it stiffer or is it just because they can? I know, it must be the NJS stamp! :)

baxtefer
05-08-06, 12:36 PM
2 reasons really:
- less demand for the 7710 to offset the increased tooling costs.
- 7701's are discontinued. The 7701's and 7710's were priced about the same when 9-speed DA was still being produced. The 7701's were over $300 new, the price you see now is the discounted "let's get rid of this 9-speed crap that nobody wants anymore" price.
shishi
05-08-06, 12:40 PM
2 reasons really:
- less demand for the 7710 to offset the increased tooling costs.
- 7701's are discontinued. The 7701's and 7710's were priced about the same when 9-speed DA was still being produced. The 7701's were over $300 new, the price you see now is the discounted "let's get rid of this 9-speed crap that nobody wants anymore" price.

You can get them and go crazy with spacers/washers if it is going to be for a conversion. Life is easier when everything lines up to 42mm though.
Renz
05-08-06, 07:48 PM
2 reasons really:
- less demand for the 7710 to offset the increased tooling costs.
- 7701's are discontinued. The 7701's and 7710's were priced about the same when 9-speed DA was still being produced. The 7701's were over $300 new, the price you see now is the discounted "let's get rid of this 9-speed crap that nobody wants anymore" price.

I didn't know they were discontinued, thanks for the info baxtefer.