104BCD crank/chainring compatibility issues issues

[Seat Sniffer]

I wanted to share my experience with this issue incase anyone else has had similar or for future knowledge to those who don't already know. I run Truvativ 104 bcd 4 bolt cranks and recently needed a new chainring because I bent my 32T. The bike came with Sram rings but I wanted to try Shimano since my Sram cassette ended up with some teeth broken off after just a couple months. I bought an XT 104mm 32T chainring. no other specs on the package. While attempting to install it, the mounting holes lined up perfectly, but the tabs would overlap the recesses on the crank so it would not seat at all. Instead of grinding them down which would have compromised the integrity of the part, I returned it to the bike shop thinking it was defective. Not the case. Every other shimano ring LX, XT, etc., had the same profile on the mounting tabs. Weird. My guess is that Shimano cranks have a 2-4mm difference in their recesses, which is about how much it was off by. Bought a race face instead and mounted just fine with plenty of room to spare. Anyone else buy 2 different parts with the exact same specs which would not work on the same application? I mean, I really think they should specify "for shimano cranks only" or "not for use on Truvativ cranks" on the package to save people the hassle.

[2wheel_lee]

I hear your frustration. However, keep in mind that Shimano only designs parts to fit their own components, hence the name Shimano on the packaging. They would never have options that say - as far as I could imagine - "for Shimano" or "for non-Shimano."

By the way, I've never heard of this problem, but that's not to say you didn't experience it. I regularly interchange Shimano and other brand rings on Shimano and other brand cranks (including Truvative cranks). Apparently, I've never encountered the same mismatch that you have.

[autoduel]

I had to grind down my Ritchey big ring to fit a profile spider on a M950 crank
Well, I guess that was to be expected with that hodgepodge of parts..........
Have dremel, makes compatible.

[nintense]

And every shop should know it.
If it makes you feel better, Shimano new XT rings are not even compatible with old XT cranks.
P.S. Race Face rings are much better.

Originally Posted by Seat Sniffer

I wanted to share my experience with this issue incase anyone else has had similar or for future knowledge to those who don't already know. I run Truvativ 104 bcd 4 bolt cranks and recently needed a new chainring because I bent my 32T. The bike came with Sram rings but I wanted to try Shimano since my Sram cassette ended up with some teeth broken off after just a couple months. I bought an XT 104mm 32T chainring. no other specs on the package. While attempting to install it, the mounting holes lined up perfectly, but the tabs would overlap the recesses on the crank so it would not seat at all. Instead of grinding them down which would have compromised the integrity of the part, I returned it to the bike shop thinking it was defective. Not the case. Every other shimano ring LX, XT, etc., had the same profile on the mounting tabs. Weird. My guess is that Shimano cranks have a 2-4mm difference in their recesses, which is about how much it was off by. Bought a race face instead and mounted just fine with plenty of room to spare. Anyone else buy 2 different parts with the exact same specs which would not work on the same application? I mean, I really think they should specify "for shimano cranks only" or "not for use on Truvativ cranks" on the package to save people the hassle.

[genusmtbkr5]

Happened to me the first time I replaced my middle ring on my Truvativ cranks. I ended up with a race face as well. BTW, some FYI, Shimano rings will not work on Race Face cranks either.