Bottom Bracket for BTwin Rockrider 520

MrGrumpy

Huge Member
Location
Fly Fifer
Sons Btwin MTB bottom bracket is hosed, does anyone know off hand which size fits ? Its square tapered are, these all fairly standard ?
 

Cycleops

Guru
Location
Accra, Ghana
This one should do the job;
https://www.decathlon.co.uk/neco-alu-bottom-bracket-id_8234798.html
Pull the old one out, check the spindle width.
You'll need a few tools including a crank extracter.
 
Last edited:

Ajax Bay

Veteran
Location
East Devon
Btwin MTB bottom bracket . . does anyone know off hand which size fits ? Its square tapered are, these all fairly standard ?
No - Square taper bottom brackets are not "standard" as far as shell width and spindle length are concerned. MTBs normally need a 73mm, whereas the link offered to you is for a 68mm (surely Decathlon is a more reliable source than asking here). And you will struggle to find out what the fitted spindle length is without (see below).
But if you're asking this question, you're implying you'll be replacing it yourself, in which case you'll already have the tools. Pull out the current one and it'll have its spec printed on it. Otherwise your LBS will sort this for you. BBs can be a challenge to get out, especially if the left hand side is plastic. I wouldn't purchase a BB (size/spec) based on the advice of randoms on a forum. The Shimano UN55 bottom bracket is often recommended (and the couple I've had in my current road bike have given me 15,000+km, each).
 

fossyant

Ride It Like You Stole It!
Location
South Manchester
As mentioned, check first. BB shell width and spindle length is important. Shimano UN53/54 are great. If possible, get the one with the alloy locking cup - not just looks better, but fits the tool better than the horrible plastic cups.
 
OP
MrGrumpy

MrGrumpy

Huge Member
Location
Fly Fifer
Well that went horribly wrong , combination of plastic cups and seized alloy equals an absolute @“-/)£!? frame . Looks like middle son is getting an upgrade :blush: . Just as well I have unused MTB bike spare , just needs chain and tyres.
 
OP
MrGrumpy

MrGrumpy

Huge Member
Location
Fly Fifer
BB shell is not in good shape trying to knock it out ! Fortunately he has out grown the bike and I have a spare n+1 :laugh:
 
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