[rtarh2o]

I have a friend who just bought a new bike from a very reputable bike shop. He wanted to swap his k-force carbon cranks on in place of the ultregra cranks that came on the bike. The salesman asked him about how many miles he had on the cranks and he said about 6,000. The salesman said he wouldn't risk using them with that many miles and that the ultregra were just as good. I assumed carbon cranks would last as long as anything else, 6,000 miles isn't that many miles for most any components. I won't argue the quality of the ultregra cranks but I am just guessing the salesman didn't want to hassle with swapping the cranks for him and fed him a line about his carbon cranks to keep him from having to swap them out for him, or at least this is what I am hoping since I have carbon cranks on 3 of my bikes!
Anyone have any ideas on this?

 

[Ventruck]

Carbon cranks, carbon frame, carbon wheels, etc. will last as well as they were made and ridden - with occasional, exceptional weight restrictions. Since it's still new compared to aluminum and especially steel, people still question its longevity.

Best guideline in that case is if you put the miles on a carbon component or frame, you should have a sense of whether or not you were beating it up the whole time. Friend of yours would have to have been quite the abusive rider to ruin such cranks imo. As for the salesman trying to back out of more labor, I don't think so; he's probably one of those people paranoid about carbon fiber - unaware that it's been tried and tested on airplanes and space shuttles.

 

[Juanmoretime]

Sounds like he didn't want the cranks although nothing factual about it. I have about 15,000 on my current Zipp SL cranks and would expect to easily double that.

 

[orange_julius]

I have a friend who just bought a new bike from a very reputable bike shop. He wanted to swap his k-force carbon cranks on in place of the ultregra cranks that came on the bike. The salesman asked him about how many miles he had on the cranks and he said about 6,000. The salesman said he wouldn't risk using them with that many miles and that the ultregra were just as good. I assumed carbon cranks would last as long as anything else, 6,000 miles isn't that many miles for most any components. I won't argue the quality of the ultregra cranks but I am just guessing the salesman didn't want to hassle with swapping the cranks for him and fed him a line about his carbon cranks to keep him from having to swap them out for him, or at least this is what I am hoping since I have carbon cranks on 3 of my bikes!
Anyone have any ideas on this?

I don't think this bike shop is reputable.

I had a lower-end FSA Carbon Pro cranks with about 13,000 miles on them with no problems at all, and now have Campagnolo UT carbon cranks with about 4,000 miles and they still look and feel brand new.

And I know plenty of people with even more mileage on their cranks without any problems.

 

[rtarh2o]

Funny thing is that my friend bought a specialized Tarmac carbon frame, he should have warned him about the longevity of the frame
My friend is a pretty large guy, has a lot of weight and logs a ton of miles but still 6,000 miles seems minimal.
As for the shop being reputable, i should say it is one of the largest in the country and has a lot of history behind it but I guess it all depends on the sales person you happen to get, they probably have at least 20 sales people on the floor at all times and they are all busy.
Rusty

 

[orange_julius]

Funny thing is that my friend bought a specialized Tarmac carbon frame, he should have warned him about the longevity of the frame
My friend is a pretty large guy, has a lot of weight and logs a ton of miles but still 6,000 miles seems minimal.
As for the shop being reputable, i should say it is one of the largest in the country and has a lot of history behind it but I guess it all depends on the sales person you happen to get, they probably have at least 20 sales people on the floor at all times and they are all busy.
Rusty

I hear what you are saying, but it's still up to the bike shop to quality-control their employees and by extension their brand name. After all, "expert recommendation" is one of the key benefits of purchasing from an actual shop rather than going online ...

We can't judge whether the motivation of the "recommendation" was to get our of having to spend time/effort on labor, but if it were, that is totally unprofessional.

 

[MR_GRUMPY]

Carbon cranks will last forever unless you ride them in the rain or direct sunlight.

 

[rtarh2o]

I am guessing the sales person really has doubts about the longevity of carbon cranks. It could be the fact that my friend is a pretty big guy (I meant to say he had lost a lot of weight) but not huge, maybe about 220 lbs?
Again if that is the case why didn't he show the same concerns about him buying a carbon frame, seems to me he would have the same doubts. Either way I would be put off by him as a buyer.
My friend is happy though, took the bike out for it's first ride today and was really impressed. He by the way wasn't bothered by the sales person not swapping out the crank, he mentioned it to me and I thought it was strange so am just looking for opinions for my own good and my 3 carbon cranks.
Rusty

 

[frdfandc]

Quit worrying about your carbon cranks and ride. The "guy" at the bike shop is full of crap. Just because its the largest in the area, doesn't mean its the best.

Find a new shop.

 

[Peanya]

Probably saw one person who had cracks in his carbon cranks on the internet and assumed that all carbon will fail in a couple of years. Because if you see it on the internet, it must be true!!
Oh, what cranks are on that bike? I'm looking for some 6700 compact...

 

[rtarh2o]

It is not a bike shop I buy from much it is a few hours away, just go occasionally to see some cool stuff that you don't get to see often. I guess this is one of the reasons I do all my own builds and wrenching, I have never bought a complete bike, instead I prefer to build up frames myself and can re-use anything I want without anyone telling me I can't.
Anyway, the bike came with new ultregra and he decided to keep it on as far as I know.
I am planning on riding my carbon cranks until something better comes along so I hope they last!
Rusty