Which BB do i need?

cheeky_chops

Owned a Voodoo Bokor for 6+ months and the crank is making creeking/pinging noises when i apply power to both pedals... no power, goes away. Went into halford and the warranty is worth jack sh1t - frame and forks, everything else is "wear and tear". :roll: I am guessing i need to replace the bottom bracket?

Its a Shimano FC-M431 alvio with "octolink" on it. This throws up:

http://www.swinnertoncycles.co.uk/shimano-alivio-m125 - which has 4 possible all ES25's

http://techdocs.shimano.com/techdocs/bl ... ID=jg.COGL - But shimano website lists it as ES30

Either way i havent a clue what type/size i want - any advise greatly received! (ps is there a BB that is abit stronger that fits??)

jonnym5

Does it say Octalink on the arms? They do a M431 which is square taper and the M431-8 which is Octalink.

If it is definitely Octalink then looking at the instructions here

http://techdocs.shimano.com/media/techd ... 690265.pdf

you say it is Octalink which takes ES bottom brackets(splined) vs the UN which is Square taper. Reading below that you need a 126mm spindle length.

To get the 68 x 126mm size you need to go with the ES25 BB and they don't make a better one. They do higher end ones such as 105 but they are type 1 Octalink. The spines on them aren't as deep and won't fit at all. You need a type 2 version.

Basically buy this

http://www.sjscycles.co.uk/shimano-aliv ... rc=froogle

If it is only six months old I'd be arguing with Halfords, Octalink doesn't last quite as long as square taper due to the bigger axle meaning they used smaller bearings but I'd expect more. If the BB has no play in it then I'd be looking at greasing the threads and making sure it's tight as a lot of new bikes seem to have loose BBs from the factory.

Before spending the money check it's not the headset, mech hanger or bottle cage bolts that do it.

supersonic

It probably isn't the bottom bracket. Service the bike first.

cheeky_chops

Jonny really appreciate the info, yes its got octalink on the arm.

supersonic wrote:

It probably isn't the bottom bracket. Service the bike first.

You could well be right - but it doesnt sound like its the front mech if you know what i mean? I will remove it before i buy a new bb. When i say i am clueless, its just that i have never replaced a bb before - i do all the maintenance on 9 bikes (me, missus, 2 kids, 1mtb and 1 racer each and 1 tt bike). Looking forward to the day when my eldest can wield a spanner!

cooldad

cheeky_chops wrote:

Jonny really appreciate the info, yes its got octalink on the arm.

supersonic wrote:

It probably isn't the bottom bracket. Service the bike first.

You could well be right - but it doesnt sound like its the front mech if you know what i mean? I will remove it before i buy a new bb. When i say i am clueless, its just that i have never replaced a bb before - i do all the maintenance on 9 bikes (me, missus, 2 kids, 1mtb and 1 racer each and 1 tt bike). Looking forward to the day when my eldest can wield a spanner!

Presumably you've checked/tightened cranks, pedals, cables, mech, rings, headset and anything else that can creak before buying a new BB. Unless horribly abused Octolink should/could last years.
Problem is by replacing first other bits get removed and refitted and although problem may be solved, the diagnoses was wrong.

cheeky_chops

Check pedals headset, rings all fine.

Took the front mech off (well tried to, its deore and its riveted together), reseated and put it all back together. Result! Smooth as a babys bum Thanks for the advise all

I7 Extreme

hi, i was searching for info on hollowtech bottom brackets. Are all hollowtech brackets and cranks the same? and is the FSA Mega exo a hollowtech or there own thing?

nicklouse

I7 Extreme wrote:

hi, i was searching for info on hollowtech bottom brackets. Are all hollowtech brackets and cranks the same? and is the FSA Mega exo a hollowtech or there own thing?

In a word no. Yes but not exactly.

I7 Extreme

thanks, what cranksets (a few) would fit in a mega exo bb?

I7 Extreme

would an isis crank fit? http://www.chainreactioncycles.com/Mode ... elID=90241

cooldad

Fit what? The Mega Exo, or Octalink?
But neither.
I thought you were trying to replace the BB, not the cranks, so if you have Octalink you need an Octalink BB

nicklouse

I7 Extreme wrote:

thanks, what cranksets (a few) would fit in a mega exo bb?

the same as that was in there before.

I7 Extreme wrote:

would an isis crank fit? http://www.chainreactioncycles.com/Mode ... elID=90241

no.

I7 Extreme

thanks, would this crankset fit in my 68mm mega exo bb?
http://www.ebay.co.uk/itm/170981902449? ... 1423.l2649
I know its a different bb size but does the crank change?

cooldad

I7 Extreme wrote:

thanks, would this crankset fit in my 68mm mega exo bb?

Ummmmmmm

I7 Extreme

nevermind, im pretty sure it will fit anyway as they don't sell different sized cranksets on crc, i have a more important question. What crank arms will fit onto the left side of the Right hand crank i bought (looking at the title crankSET and not reading the description properly). its a gravity moto x crank ^^

nicklouse

I7 Extreme wrote:

nevermind, im pretty sure it will fit anyway as they don't sell different sized cranksets on crc, i have a more important question. What crank arms will fit onto the left side of the Right hand crank i bought (looking at the title crankSET). its a gravity moto x crank ^^

Another of the same.

And hijacking threads with stuff that has nothing to with the original is a pain in the arse.

And when refering to stuff it is best to actually link to it as who knows what you actually mean.

I7 Extreme

thanks
wont any others fit alright?

nicklouse

I7 Extreme wrote:

thanks
wont any others fit alright?

Yes if they are exactly the same.

I7 Extreme

thanks :roll: