Bicycle Mechanics - Smallest chainring is scratching the frame with a new cartridge bottom bracket.

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Senkarst
05-20-09, 05:49 PM
Hi,
i just got my bottom bracket change on my hybrid at a bike shop.
And when i tried to put back my cranks set, the smallest chainring is so close to the chain stays it is really hard to spin the crank and scratching it.
I know that before changing the bottom bracket, the crank was fine, and tried a other crank set and same result.
So can it be the bottom bracket ?
Can a cartridge bottom bracket been adjust ?
I'm new to repairing bike, and from what i understood it can't.
Is the crankset a triple?
If so is the bottom bracket for a triple?
Al
Senkarst
05-20-09, 05:57 PM
Yes it is a triple crankset.
How could I know if it made for a triple ? (without removing it)
The mechanic at the bike store, showed me a bottom bracket, told me it is the same thing I had.
And he told me to come back when it would be done, so I assume he got the right one.
I guess my mistake was to remove my crankset at home to fit it more easily in the car.
I should have bring it with me, and that whole thing most likely wouldn't have happen.
johnknappcc
05-20-09, 05:58 PM
Sounds like the BB spindle is too short for your crankset. If you previously had an aymmetrical spindle, the cartridge BB would need to be longer (symmetrically) to compensate for the difference. For example I have a 121.5 asymmetrical spindle for a triple. A similar cartidge BB would need to be 127mm to compensate and still give me the appropriate chainline/clearance. More info would be helpful
Torchy McFlux
05-20-09, 06:00 PM
The bottom bracket spindle length is wrong for your crank.
Take it back to the shop (with the crank) and have them install one with a longer spindle for you.
Senkarst
05-20-09, 06:10 PM
Thanks all, gonna head back to the bikeshop, as soon as I can to see what they can do.
Yes it is a triple crankset.
How could I know if it made for a triple ? (without removing it)
The mechanic at the bike store, showed me a bottom bracket, told me it is the same thing I had.
And he told me to come back when it would be done, so I assume he got the right one.
I guess my mistake was to remove my crankset at home to fit it more easily in the car.
I should have bring it with me, and that whole thing most likely wouldn't have happen.
Did you give the old bottom bracket to the mechanic and ask for the same one?
Did you tell the mechanic it was for a triple?
It sounds like the mechanic made the mistake. Learning to do your own wrenching is a good thing. The only thing you may have done wrong was not offering enough information. I think you did the right thing.
merckx_rider
05-20-09, 07:56 PM
Hi,
i just got my bottom bracket change on my hybrid at a bike shop.
And when i tried to put back my cranks set, the smallest chainring is so close to the chain stays it is really hard to spin the crank and scratching it.
I know that before changing the bottom bracket, the crank was fine, and tried a other crank set and same result.
So can it be the bottom bracket ?
Can a cartridge bottom bracket been adjust ?
I'm new to repairing bike, and from what i understood it can't.
Sounds like the shop installed the wrong BB
johnknappcc
05-20-09, 08:38 PM
Oh, one other thing. If it is a square taper, make sure he used the proper taper (either JIS or ISO). But most likely, the spindle length is wrong.
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