Warped Chainring?

I have had the same problems with campag chainrings and BB's.

I have been told it is because i turn a big gear and am a powerful rider.
I got through 4chainsets in 6months during the season.

A Record BB lasted me 6months before i blew the bearings.

Might be woth you speaking to some one though.

EagleVT94 said:

I have a question about what is considered 'normal' warp in the chainring...if any. I just dropped a size from my DA 175 cranket to a DA 172.5 and I am not sure what to think. There is no play in the bottom bracket, but as the crank turns, I'd say the chainring has about 3-4mm of warp/wobble to it.

Could the bottom bracket be misaligned? Can the chainrings be that warped? I would like some opinions before I call for a defect claim. Just put it in, haven't even been outside yet!

Thanks.

Sounds excessive to me for an expensive DA crankset....1 mm seems more like it.

I'd go back to the seller and ask them what the runout should be. If they are a Shimano-retail dealer, they should know or can find out quickly. Was this a brand-new retail part, in a box?

Thanks for the replies...I finally have had the chance to take a closer look, and it appears the large and small chainring move in unison.

So now I am thinking BB? Everything appears to be in there solid. This week I plan on taking it to a friends house to take it apart on his bike stand (he has the tools!)...Anything in particular I should focus on?

EagleVT94 said:

Thanks for the replies...I finally have had the chance to take a closer look, and it appears the large and small chainring move in unison.

So now I am thinking BB? Everything appears to be in there solid. This week I plan on taking it to a friends house to take it apart on his bike stand (he has the tools!)...Anything in particular I should focus on?

Don't believe it's in the BB, but would guess the crank isn't completely seated on the axle. Did you use grease or anti-sieze compound on the splines and torque the bolt up to specs?

If the crank is seated fine, would be a bent spider or machining defect in the crank....but that seems unlikely to me in a brand new part with warranty.