Join Date: Jul 2013
Location: Glendale, WI
Bikes: Franken-mountain bike, mid-90s Performance TR1000, 1990 Cannondale ST400
Crank ring spacing 7/8 vs 9 speed crankset
Hello again folks,
Back to pick your collective brains! I use my trusty ol' frankenbike for both winter as well as trail riding (and formerly for year round commuting before I got my road bike), and the drivetrain is getting pretty tired. After riding this winter, all the snow and salt has started taking a noticeable toll despite my best efforts to clean everything up after I ride. Not to mention the parts that I used when putting the bike together are 2006 Acera 3x7 components which had been in use for quite a while before I wrecked really hard as a kid and decided to take a break from mountain biking. So, I recently began investing in a 9 speed upgrade. Thus far I've got a set of SRAM X9 ball bearing shifters, with an X7 rear and X5 front derailleurs, PG-970 cassette and a chain on the way.
As money doesn't grow on trees, and the crankset being the most expensive part of this upgrade, I wonder if I can get away with using my old one for a while. Looking online, I've seen some people say a 7/8 speed crankset will work OK with this setup (with front shifting being a bit tedious but doable), while others say that it won't work at all. So, my question(s) to you:
From personal experience, can anyone confirm or deny whether such a thing will work? Or, alternatively, can anyone definitively quote the chainring spacing difference between 7/8 and 9 speed cranksets? I can't seem to locate it online, even on Sheldon Brown's site.
My backup plan at this point is to run it as a 1x9 until I can afford a decent 9 speed crankset, since I don't leave the middle chainring on the trail unless I'm fighting a particularly steep climb.
Thanks in advance for your input!