BB Advice Please

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Spoons47

Well-Known Member
I think my BB is quite noisy and was wondering about cleaning and greasing or would just buy a new one if that is better. Its a felt F95 that I have only had a month or so and is in very good condition. The number on the bottom of frame is FT40. I really don't know where to start but am keen to have a go, seeing as I have a friend round the corner who can help me if I get stuck, who also has all the correct tools.
thanks in advance.
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JhnBssll

Veteran
Location
Suffolk
Looks like a square taper, so a UN55 would probably be your best bet. They don't tend to be serviceable so if it's noisy and feeling rough it's time to swap it out.
 
Location
Loch side.
I think my BB is quite noisy and was wondering about cleaning and greasing or would just buy a new one if that is better. Its a felt F95 that I have only had a month or so and is in very good condition. The number on the bottom of frame is FT40. I really don't know where to start but am keen to have a go, seeing as I have a friend round the corner who can help me if I get stuck, who also has all the correct tools.
thanks in advance.
You say you think the BB is noisy. Why not first find out if that is the case, before dealing with it? There's no use for all the speculation until you've actually diagnosed the problem (or not).

To isolate all other drivetrain noises from BB noise you have to remove the chain or, shift and maneuver it so that the chain is off the chainrings and lies on the BB shell, without touching any crank parts. In other words, if you now spin the crank, the chain is not involved and not even touching.
Now spin the crank and hold your ear against the frame somewhere where the pedals won't remove your teeth.
A good BB says "shhhhhhhhhh leave me alone".
A bad BB says "rrrrrrrrrreplace me".

Do that and report back.
 

I like Skol

A Minging Manc...
As YellowSaddle says & also just grab one of the cranks then push & pull it sideways (not rotating the cranks) to see if there is any play, there shouldn't be any. Don't hold the pedal to do this as you might get a misdiagnosis if the pedal has any slack (which it also should not have).
 

Outlaw Hobbs

Senior Member
Location
Herts
Assuming your bike is not only a month old and it is definitely the BB that is noisy or rough then replace it. As the chainset is FSA then the BB will likely be branded 'RPM' which I think is same company. My advice regarding removing the old BB would be get your friend to show you how to do it first time as it is easy to make a Horlicks of the job and get yourself into a world of pain. The replacement must be the same axle length exactly in order to keep your chainline correct. Obviously it must also be the correct shell length probably 68 mm and the same square taper probably JIS.
I recently wanted to change my FSA cranksetted BB and found it was branded RPM and an odd length (103 mm) and could find few suppliers that stocked this size.
 
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Spoons47

Spoons47

Well-Known Member
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Thanks for all the quick replies. Amazon have the un55 under £12 that I can get delivered tomorrow, so no brained really. these are the sizes they have. I’m going to need to phone my son to measure it as I’m on my way to work. Can I have some instructions for measuring and I can text them to him.
Cheers All
 

rogerzilla

Legendary Member
The protrusion on the RH side is critical. Some BBs are symmetrical and some not, so axle length alone is not necessarily a good guide unless it's rhe same model. It will be JIS taper, which is most BBs these days; only a few European manufacturers use ISO taper.
 
Location
Loch side.
OK, so you've made up your mind. After a month your BB is worn out and noisy. Good luck with the next one. I hope it lasts longer than one month. Better check the headset bearing as well.
 

midlife

Guru
In just a bit confused, is it a used bike that you have had for a month...... Or a new bike that is a month old?
 

midlife

Guru
As far as I am aware UN55 are measured by the width of the BB shell (of the bike) and the length of the axle itself.
 

Milkfloat

An Peanut
Location
Midlands
It says quite clearly in the post I have had the bike for a month. I love a bit of banter but absolutely no need for sarcasm !!

Only one minute before this post, so it was not clear at all. You ignored the first chance to let us know the bike was not a month old. As YS says, you still don’t know if the BB is knackered.
 
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