[donalson]

i've got 2 cranksets on 2 different bikes, both use the same bolt patterns (truvativ stylo, and stock redline d440 crank made by RPM)

on the center ring the chainrings don't sit properly, they seem to have a different "cut" at the edges so they don't lay flat against the crank... my thoughts are this notching is to distribute the pressure away from the little bolts and apply it to the crankset itself...

so the question is... would it be safe to take a file to the chainrings to get them to sit properly or is that a no-no...

and 2nd question... if i buy an aftermarket ring, will I have the same problem?

figured you guys would know
thanks
mark

 

[FBinNY]

Absolutely no problem filing the rings. Regardless of other points of contact, the main load (torque) is always taken up by the bolt set. You;ll note that most inner rings are only supported by the bolts.

You might, but shouldn't have to file other rings the same way in the future. The diameter of the shoulder on crank arms used to be pretty standard, but nowadays lots of companies are doing their own thing, maybe in an effort to capture the replacement ring market.

Lastly, if the chainring has pick up pins, ramps, or cutouts, look for a "timing" reference, to orient the ring for best shifting performance. Otherwise you have a one in five chance of getting it right.

 

[mtnbiker72]

Even though the bolt pattern is the same, different manufacturers flanges on the crankset are different. For instance, when I put a Shimano middle ring on my last set of RF cranks, I had to file quite a bit of the chainring flanges to get it to fit. It worked perfectly fine after I did it, but over the years I've found that the Shimano rings don't fit well with RF and Truvativ cranksets...even though they use the same bolt pattern.

 

[donalson]

thanks guys... just what i wanted to hear ... the redline crank is a little heavy... but it's beefy... and the stylo crank is a little flexy under me.... so perfect