Bearing Damaged in Bottom Bracket

A_Sober_Paddy

So out on a spin today and noticed my front chain ring didn't look straight as i looked down as cycle so got off and inspected it. Small bit of give in it, nothing major and only when the drive side pedal was down.

Stopped into the LBS and they said it seemed like a bearing, but were unable to take the bike in as they were full and it wasn't a major issue. Was told to use lower gear, avoid getting off the saddle and you should be fine, but if it gets any worse to bring in back in.

As it stands i'll be dropping it in next friday for it to be sorted...

But was just talking to a friend who said i shouldn't cycle on, it will break, now there isn't much give in and if i follow the instructions of the LBS i should be ok right?

nilhg

It really depends on what the problem is, if the bearing is just slowly failing then it could go on for quite a while (or collapse tomorrow) but if it's seized and the shaft of your crank is turning inside it then you could do some expensive harm.

It's really hard to know without pulling off the crank arm and slipping out the crank.

WillyFXP

If it's so far gone you can see the chainring being out of alignment then I'd say its fairly dodgy, I personally wouldn't ride it.

magicmonkeys

To be honest, you're better safe than sorry. A BB is less than a tenner new on Amazon and if you can't do it yourself, the LBS should install it for a reasonable price too.

A_Sober_Paddy

WillyFXP wrote: »

If it's so far gone you can see the chainring being out of alignment then I'd say its fairly dodgy, I personally wouldn't ride it.

Only noticed it because of the deraileur just noticed a little,

Mechanic365

Depends on what kinda bb and cranks you have, if you tell us we can tell you what to do.
Bearings in bottom brackets nornally get stiff rather than ware out because cranks never go over 140rpm and dont get hot but ive found that cartridges bb's ware out faster than most, if it is one of these then its fine to keep using because its only the bb that will get damaged.
The only big concern is your health, heard of knee problems from bad cranks and bb.

A_Sober_Paddy

Mechanic365 wrote: »

Depends on what kinda bb and cranks you have, if you tell us we can tell you what to do.
Bearings in bottom brackets nornally get stiff rather than ware out because cranks never go over 140rpm and dont get hot but ive found that cartridges bb's ware out faster than most, if it is one of these then its fine to keep using because its only the bb that will get damaged.
The only big concern is your health, heard of knee problems from bad cranks and bb.

Well the lad in the bike shop was the guy who fitted it, also he could have taken the bike in but he'd not have gotten to it until late in the week, his on his own for a few weeks for some reason.

With regards to bad knees, is that from constant use of using a poor condition crank...Like i just went and had a look at it again, there really isn't much movement, you need to use two hands and really use some force to move it by hand

Mechanic365

A_Sober_Paddy wrote: »

Well the lad in the bike shop was the guy who fitted it, also he could have taken the bike in but he'd not have gotten to it until late in the week, his on his own for a few weeks for some reason.

With regards to bad knees, is that from constant use of using a poor condition crank...Like i just went and had a look at it again, there really isn't much movement, you need to use two hands and really use some force to move it by hand

Aragh if thats the only play in it then its fine.
The bad knee problems ive seen are from using a bottom bracket thats litruly falling around the place.
If you take a quick picture of one of the cranks I can tell you what you need to replace the bearings and if theirs any chance that the cranks will become damaged from using them

A_Sober_Paddy

Mechanic365 wrote: »

Aragh if thats the only play in it then its fine.
The bad knee problems ive seen are from using a bottom bracket thats litruly falling around the place.
If you take a quick picture of one of the cranks I can tell you what you need to replace the bearings and if theirs any chance that the cranks will become damaged from using them

Mechanic365

A_Sober_Paddy wrote: »

If thats only rocking side to side it could be just not tightened properly, id say you can keep using it as long as it isnt hard to turn the cranks (they shouls be very free) if they are hard to turn then you need to change it.

If you have a few allen keys and the aldi bike mechaics set you can change it anyway, heres the bb you need (you can get whatever leval bb you like such as tiagra, 105, ultegra...) but this one eeems very good value
http://www.chainreactioncycles.com/mobile/ie/en/shimano-5700-105-bottom-bracket/rp-prod50450

And theirs numerous guides online on how to replace it

JPWOctane

Quick and easy enough job. If you don't have a BB tool yet, don't buy the Aldi one. I had one and it stretched mid-job, just like the cone spanners did. I bought a much better one in Halfords to finish it.

Here's a good, clearly explained guide. Only the beginning and end are relevant (the middle is about maintenance of the bearing but prob too late for you!).

Can't post the link but if you search eighteenbikes and bottom bracket on YouTube you'll find it.

Juan More Time

What you have there is a shimano hollowtech 2 bottom bracket with an english thread.
There are plenty of instructional videos on youtube if you fancy attempting the repair yourself. The only specialist tools required is the splined spanner to remove the worn out bottom bracket cups. This tool usually includes the special star shaped widget to undo the compression bung on the left hand crank arm, before you can unfasten the two 5mm allen screws that secure the left hand crank arm to the bottom bracket axle.

The spanner is usually about twenty euro.

If you are the least bit unsure of your mechanical skills, it's safer to have the repair done at a reputable bike shop.