BB - I have searched already though...

Travs

Well-Known Member
Location
Surbiton
Hi all,
Was out for a ride - pretty damp but not overly wet conditions. Sound from BB sounds like its full of sand but only when I'm in the higher gears on the rear cassette - irrespective of which crank I'm in. Is this a classic? You can hear this when you spin the cranks backwards when off the bike. And I've occasionally felt a slight vibration through the left crank too on occasion.
I took it to my LBS who did a BB service (I assume taking apart and re-greasing although admit I didn't interrogate them on this). It was ok for one ride, but second ride after, a little damp, and its back again.

I'm not au-fait with it all and have tried to research but I have no idea what I've got on the bike. Izoard XP Ultegra's appear to have FSA MegaExo but I haven't found what design/type it is, and therefore what I need to look for to remedy - I'm thinking replacement seeing as servicing hasn't done it. If there aren't other options for me to look at? It runs Ultegra but I've just red that Shimano Hollowtech 2 aren't particuarly long-lasting. If they fit in the frame? Jeez I feel dumb...

Cheers,
Lee
 

young Ed

Veteran
firstly don't feel dumb, even those on here that are expert enough to open a bike shop (not me by a long way!) get stumped occasionally.
the problem with bad sounding sounds are that they almost always mean something is wrong but even if they sound like they are coming from for example the BB they might well be coming from somewhere completely different! try shifting to a lower gear that doesn't have this noise (to get it out the way) and then check right round the cassette to check for any damaged sprockets any where (visually check all gear especially the higher ones). is it changing in and out of the higher gear ok? if you own or have access to a mobile repair stand or other wise get someone to lift rear wheel up or even flip bike over (lay saddle and bars on an old towel or t shirt etc to protect them from scuffs) then spin the cranks to move the whole drive train and then shift the gears through every gear on the rear and check to see derailler is moving nicely and it is not damaged etc
apart from that LBS :sad:
Cheers Ed
 

Citius

Guest
Izoard XP Ultegra's appear to have FSA MegaExo but I haven't found what design/type it is, and therefore what I need to look for to remedy -
The bit you've written - ie the bit I've highlighted in bold - is what BB type you have. If it is the BB which needs replacing (which isn't clear cut, by what you have described) then that is what you will need to ask for.
 

tyred

Legendary Member
Location
Ireland
If it only happens in the high gears could the chain be rubbing the outer edge of the front mech cage (assuming you have a double or triple chainset)? Do your shifters allow you trim the front mech at all?

If you really feel bb, take off the chain and turn pedals, check for play/grittiness in the bearings.
 
OP
Travs

Travs

Well-Known Member
Location
Surbiton
Thanks guys - its not the shifting, its when I'm pedalling in the "top half(ish)" of the cassette. Gear shifts are smooth and accurate as have always been. I'm thinking replacement but just wondered whether that particular sound is particularly synonymous - or whether the fact that its only half the cassette means it may attributable to something else. I'm thinking that its take to shop and get them to investigate though, I agree chasing sounds is frustrating etc.

Citius - I know that's the model, I just wondered whether I could take the opportunity to upgrade and therefore whether there were better models that fit BB30 or PF92 or XXBXtg-something-something (I'm just making stuff up now) or whatever the design of BB it is. I don't know whether there are different MegaExo's depending on what frame they went into etc. But take on board that I will make sure its definitely that

Tyred - its a good point, I will have a good look but I'm pretty sure I've had a good look. I also get the impression the sound is slightly more solid than chain on thin metal, if that makes sense but happy not to rule anything out until I've definitely had a look.
 
U

User6179

Guest
Hi all,
Was out for a ride - pretty damp but not overly wet conditions. Sound from BB sounds like its full of sand but only when I'm in the higher gears on the rear cassette - irrespective of which crank I'm in. Is this a classic? You can hear this when you spin the cranks backwards when off the bike. And I've occasionally felt a slight vibration through the left crank too on occasion.
I took it to my LBS who did a BB service (I assume taking apart and re-greasing although admit I didn't interrogate them on this). It was ok for one ride, but second ride after, a little damp, and its back again.

I'm not au-fait with it all and have tried to research but I have no idea what I've got on the bike. Izoard XP Ultegra's appear to have FSA MegaExo but I haven't found what design/type it is, and therefore what I need to look for to remedy - I'm thinking replacement seeing as servicing hasn't done it. If there aren't other options for me to look at? It runs Ultegra but I've just red that Shimano Hollowtech 2 aren't particuarly long-lasting. If they fit in the frame? Jeez I feel dumb...

Cheers,
Lee

I think you need a BB English thread external bearings, Size 1.37 x 24tpi x 68mm is the size .
 
U

User6179

Guest
Don't buy the cheap shimano ones like this , they can be a hit or miss , but this is the type I think you need, sizing on left cup .
upload_2015-3-2_17-13-33.jpeg
 

BigAl68

Über Member
Location
Bath
Planet x normally have good deals on mega exo BB. Just get a new one fitted and get back to happy pedaling
 

Citius

Guest
MegaExo cranks have a 24mm spindle and you need a BB designed for a 68mm shell. If in doubt, just fit a Tiagra or 105 HT2 BB
 
OP
Travs

Travs

Well-Known Member
Location
Surbiton
Ok - massively got the wrong end of the stick.
It looked as though my front mech is rubbing but went on Wiggle Ashdown today and the bike mech beforehand said I've got trim adjuster on the front mech - gentle tap on left down-change releases 4mm of cable which just brings the mech over a tad. Easy.

The grinding is a little more embarrassing. Turns out when I'm cleaning the chain after a ride, I'm overlooking specifically cleaning grit off the outer side face of the teeth on the big ring. Ergo - chain is clean but it then picks up grit again and grinds away. I'm an idiot
 
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