Hi everyone,
I own a Surly LHT with a 22/32/42 "MTB" IsoFlow Truvativ triple chainring set. I run a 9 speed cassette. The middle chainring is likely due for replacement - some of the teeth have sharp and irregular shapes. The largest and smallest chainring seem ok. Does SRAM still make this model or are new Isofolow Truvativ chainrings available somewhere? If not, can I readily substitute a different brand chainring?
Thanks,
Neil

Which version do you have? With only three mouse clicks you can search and find lots of info on line. You need to know if the rings are bolted onto the arms, the number of bolts (4 or 5) and the bolt pattern diameter. I pasted IsoFlow Truvativ into my search box and got many links to photos and sellers with specs. What we can't do for you is to see yours or know it's version. Andy.

Hi Andrew,
Thanks for your response. Sorry for being vague - I am new to bike repair and working my way up up the learning curve. There is no model number on the crank arms or chainrings that I can see. Looking at the outer/ largest chainring, I see 4 bolt on the outer edge of the chainring. Those bolt holes are empty. Looking at the middle of the outer chainring, there are 4 bolt holes which are bolted to the middle chainring. Looking at the smallest/ inner chainring, there are also 4 bolt holes. The bolts shoot through all 3 chainrings. The crank arms are as far as I can see bolted onto the outer chainring. They look a lot like the AKA crankset on the SRAM website, thought my set was purchased new in 2010.

Brooklinebiker- no, the outer and middle rings share a mounting bolt. The innrer ring has it's own set of bolts. Looks to be a 4 arm 104 for the mid and large rings. You need to learn to look closer at the interfacing contacts of parts and figure out the aspects that don't relate to the rest. Now you have a guide to find your middle ring. Thing is if you had been able to go to a LBS this would have taken only a few minutes to figure out. Andy.

Thank you Andy.