mightypudge

During my ride yesterday, one of the teeth on my middle chainring bent inward. When I got home I was able to use a pair of pliers to bend it back into place. No big deal.

After I cleaned the bike I inspected all three chainrings and noticed many of the teeth on all three chainring are already showing a lot of wear. Some of the teeth appear to already be worn into points. I only have 85 miles on the bike so far, and I can't imagine Cannondale would use cheap chainrings on a $1800 bike (or, would they?).

Is this kind of wear normal? What are my choices for better quality chainrings?

DnvrFox

Chain rings use different size and differently facing teeth to assist in shifting. The tooth you bent "back" was probably designed the way it was. Be careful in messing with that stuff.

sch

You have discovered one of the major innovations of the '80s: tooth shape, along with those little curved and ramped cutouts on the inside of the middle
and large chainrings greatly facilitate shifting by picking up the chain faster and allowing it to be inserted on to the chainring before it is fully lined up. A brief look at a new bike will show the different tooth shapes are present when new.
The alloy chainrings are made of is good for 8-20kmiles of riding on the road.
Mud bugs get shorter life spans. Steve

Dave Stohler

Yeah, you probably just ruined a perfectly good $50 chainring. When it doesn't shift right next time you ride, go down to the LBS and buy yourself a new one.

miamijim

I dont think you ruined the chainring. A few good firm shifts might put it back in its proper place. Would Cannondale use cheap chainrings? Hell yea they would. Unless your chainrings are forged they are cheap. I would never buy any rings other than genuine Shimanos. They are expensive for a reason. Most 'house brand' parts are cheap, thats why they use them.

mightypudge

According to the bike shop where I work, also a Cannondale dealer, the chainrings on the Scalpel 800 are sort of cheap from the factory. Most times they recommend that serious riders upgrade the crank or chainrings to something more sturdy.

The service manager at my shop checked out my ring today and I did *not* bend back the shifting tooth. When I explained what was happening yesterday he told me he would done the same thing. He also completely checked the drivetrain over to make sure it was shifting OK, which it was.

mightypudge

I was very careful to not bend back the wrong tooth. I checked out all three wheels and identifed the shifting point so that I knew I was doing the right thing.

What was happening yesterday on my ride was that at every revolution of the crank, my chain would try shifting from the middle to the small chainring. Of course it wouldn't make it because the derailleur was still in place, so it would jump back. This caused a skip in the revolution that made me hop off the bike to inspect it.

It happened when I shifted to the large chainring and simultaneously stood up to climb. I figured I'd gotten up to early and bent the tooth during the shift. The service manager at my shop said that sounds very likely.

Once again, thanks doe the tip. I'm probably going to pickup a new chainring set anyway, but it's good to know I was able to fix the current ring.

mightypudge

I'm pretty much in agreement there. Besides Shimano, would you recommend another brand? I was looking at stuff from TruVativ and Race Face. With my employee discount taking effect shortly it makes sense to go for the gusto.

DnvrFox

Wow, a pretty bad chain ring.

Your first post gave no hint that you knew what you were doing, which is why you probably got so many responses from folks who thought you did not know.

mightypudge

My thoughts exactly.

My fault. I apologize.

TrekRider

I bet you haven't been flossing after every ride have you?

Dannihilator

Race Face makes some downright indestructable chainrings.

MichaelW

The best 3rd party chainrings are probably Specialities-TA. They are available in any tooth count for any crank pattern, as individual rings or matched sets, with all the usual ramps and pins.
A lot of professional teams use TA rings on their Campy or Shimano cranks.

skdsl

I bought some Deore cranks almost two months ago, and upgraded the middle ring to an alloy one which I was told was LX/XT quality. I have done a little over 700km on them and the middle ring is toast. I was a little dissapointed to say the least. It had worn to a stage where the front of the teeth had mushroomed out and under high pedalling load it would throw the chain off the middle ring, and I would smash my knees into the headstem. I replaced the chain just after I got the cranks, and it is still OK now. The teeth that showed the most wear were the thin ones with shifting ramps, so if I destroy this one too quickly, I may have to use a DH middle ring without the shifting ramps.

VO2 MAX

dont mess with stuff u dont understand, would be my advise. If it was a new bike, take it back to the shop.

Richard D

As far as I'm aware the cheaper Shimano Steel rings last considerably longer than their alloy rings, but you do have the weight issue to consider.

Richard