Chain skip from chainrings?

[larsonian]

I put a new chain on an old road bike I inherited and replaced the rear cassette. I went to ride to work today and I had what appeared to be chain skipping within a few feet of leaving the garage. I knew a new chain and old cassette could cause this, but I hadn't heard of this happening in the front also. I will take a closer look this weekend when I have time, but that seems like a logical first place to start.

It's a 12 year old bike and my Dad rode it often for the first few years. Original crankset I believe.

[attachment=4067]

[DaveM]

The chainrings do look a bit worn, but you're right, this is fairly rare.
Does it happen the same on both front chainrings?
Does it only skip under high pressure pedalling?

If yes to the first or no to the second, I would suspect something else first. (stiff link in chain, need der. adjustment, etc)

[larsonian]

(04-04-2013, 08:49 PM)DaveM Wrote:  The chainrings do look a bit worn, but you're right, this is fairly rare.
Does it happen the same on both front chainrings?
Does it only skip under high pressure pedalling?

If yes to the first or no to the second, I would suspect something else first. (stiff link in chain, need der. adjustment, etc)

Ahh, good question! I put it on my trainer and set it to the highest resistance. Immediate skipping in the middle chain ring like this morning (it's an old 3 ring 105 set) but when I moved to the larger ring with the same resistance, there was no problem. I think that pretty much seals the deal on replacing the crank set. Thanks for helping me whittle down the possibilities

[Painkiller]

have you tried finding a new chainring? that would save you the expense of a whole crankset. what is the fc-xxx model number? it will be stamped on the back of the crank arm

[larsonian]

(04-04-2013, 09:45 PM)painkiller Wrote:  have you tried finding a new chainring? that would save you the expense of a whole crankset. what is the fc-xxx model number? it will be stamped on the back of the crank arm

Hey, another good idea! It's a FC-5504, 9-speed Shimano 105 41T middle chain ring that is giving me the problems. It looks like this would be a good replacement (same BCD but it's an Ultegra):

Shimano Ultegra 9-Speed Triple Chainring (Silver, 42 Tooth) by Shimano
Permalink: http://amzn.com/B001P9IQJM

I was thinking of replacing the entire crankset because this 12 year old bike probably saw 2,000mi/year for the first 6 years and it is probably due for a replacement. I was looking at the Nashbar CR2, with a new bottom bracket for a total of $90. But I wouldn't mind saving the money.

Opinions?

---

Actually, would this work:

Vuelta 130/42 Tooth Road Bike Chainring
http://www.nashbar.com/bikes/Product_10053_10052_502585_-1___

[Painkiller]

I would think the ultegra or the vuelta would suffice for a replacement
the nashbar cr2 is ok for the money but would require an isis bottom bracket
I used one on my trek commuter 14spd (double)
now that I see it again this bike is a Nashbar showcase, Ha
seat,crankset,seat post, skewers,barends, waterbottle holder

[larsonian]

(04-04-2013, 10:30 PM)painkiller Wrote:  I would think the ultegra or the vuelta would suffice for a replacement
the nashbar cr2 is ok for the money but would require an isis bottom bracket
I used one on my trek commuter 14spd (double)
now that I see it again this bike is a Nashbar showcase, Ha
seat,crankset,seat post, skewers,barends, waterbottle holder

My bikes are turning into the same thing: Nashbar tires, chains, bar ends, stem, I could go on. I knew I was going off the deep end when I looked into Nashbar brifters...

I'm leaning towards the CR2 crank since the components are so old anyway. Under $100 with BB. Will be able to ride for a few more years on this 2001LeMond since this will make a complete drive train replacement