Hey all! I discovered that my middle/36 tooth 5-bolt chainring has multiple cracks. I’ve also read that they could be shift ramps (drilled holes) and that they and the flatter teeth could be on purpose. The other two chainrings (46/26) have some wear that is even.
Im trying to "restore" the bike and keep it as original as makes sense, with minimal cost. For folks with more experience and knowledge than my virtually nothing, does this need repair? Cracks/ramps are unevenly spaced on ring.
If yes, what are my options to replace this one ring? I'll mention that I have already replaced the cassette (lightly used Shimano part) and chain (new KMC).
Do Shimano replacement parts exist for these vintage bikes with 3×7 drivetrain?
Is there another manufacturer that makes compatible parts? (SRAM etc.) Not looking to make significant changes if possible.
Is there a way for me to look up part numbers or compatibility as a newbie who wants to learn and do as much of the work as possible myself?
Pics for attention
by Expensive_Passion_80
4 Comments
Those are shift ramps, all normal there. As for the teeth, they look great. 7 speed drivetrains are very strong and can last forever
Definitely not normal and broken and worn! chainrings are available, but it might be worth it and or cheaper it to just get a new crank set, they run $30-50 depending on what you get.
Fuckin lol at these chump comments so far. Yes, that ring is extremely worn. No, that is not shift ramping or anything even remotely resembling it (the wear that is, the ‘crack’ is indeed a form of ramp’) That’s as crazy as the idea that birds are real, and not government spies.
But yeah obviously that ring is toast and needs to be replaced. Like, obvious enough that anyone looking at that and disagreeing that it is worn can just be ignored forever. On anything. Matters of taste even.
There very well may be information printed on the ring which you would need to know in order to spec a replacement. This includes BCD and tooth count, although you could simply … count the latter. And make sure you select a middle ring, otherwise your spacing will be fucked.
And also use grease. And threadlock. Know what? Just bring it to a bike shop. Or I’ll strangle you.
Lol best of luck!!!!
It is very common in steel chain rings to see this; where they drill a small hole at the end of a split so that they can build a shifting ramp on the chain ring.
The reason why it’s a giveaway that it was manufactured that way is that’s not the only place on the chain ring these occur.
Whether or not the actual teeth on the chainringer worn can be determined by wrapping a brand new chain around it. If the chain tries to climb out of the chain ring, then the chain ring is worn.