Determining Bent Cranks /Spider & Not True New Chain Rings
wolfsbane2k
Posts: 3,056
Hi.
Following a crash a month ago where the two outer chain rings on my triple crankset MTB got a thump because my ankle got jammed between them and the car's wheel ( and I don't know what quite happened with the crank/pedal), I've had the bike "repaired" by the drivers shop where they bend the outer chain ring straight (despite being asked for a new ring) and put a new middle ring on, and stated "The cranks fine".
However, after riding it for a 2 miles, Its felt very odd and the middle ring can be seen to be wobbling all over the place, which for a brand new ring just isn't right. I've video'd the wobble, which clearly shows the spacing between rings changing, and the chain suddenly "kinking" on a specific tooth by the crank arm. I'm not sure if the kinking is a tooth/ramp to gear changing, but seems very odd.
Is there a specific way to determine if the cranks/spiders are bent and therefore should be replaced, vs just a poor fitment of the chainrings, possibly for the purpose of solicitors/insurance claims?
Because it's an insurance job, I'm likely to get into argument with someone over "proving the job wasn't done properly", as I'm thinking of taking to a different shop and getting the BB and crankset replaced, as they originally recommended
Thanks in advance,
Following a crash a month ago where the two outer chain rings on my triple crankset MTB got a thump because my ankle got jammed between them and the car's wheel ( and I don't know what quite happened with the crank/pedal), I've had the bike "repaired" by the drivers shop where they bend the outer chain ring straight (despite being asked for a new ring) and put a new middle ring on, and stated "The cranks fine".
However, after riding it for a 2 miles, Its felt very odd and the middle ring can be seen to be wobbling all over the place, which for a brand new ring just isn't right. I've video'd the wobble, which clearly shows the spacing between rings changing, and the chain suddenly "kinking" on a specific tooth by the crank arm. I'm not sure if the kinking is a tooth/ramp to gear changing, but seems very odd.
Is there a specific way to determine if the cranks/spiders are bent and therefore should be replaced, vs just a poor fitment of the chainrings, possibly for the purpose of solicitors/insurance claims?
Because it's an insurance job, I'm likely to get into argument with someone over "proving the job wasn't done properly", as I'm thinking of taking to a different shop and getting the BB and crankset replaced, as they originally recommended
Thanks in advance,
Intent on Cycling Commuting on a budget, but keep on breaking/crashing/finding nice stuff to buy.
Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...
Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...
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Comments
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Use a rule against the base of the rings (mounting bolts) to the frame to check for a bent spider.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0
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That's what I thought - thanks.Use a rule against the base of the rings (mounting bolts) to the frame to check for a bent spider.
I had to find a small steel rule for that, but thanks - the crank spider is out in 2 places, just not sure which 2!Intent on Cycling Commuting on a budget, but keep on breaking/crashing/finding nice stuff to buy.
Bike 1 (Broken) - Bike 2(Borked) - Bike 3(broken spokes) - Bike 4( Needs Work) - Bike 5 (in bits) - Bike 6* ...0
