replacing bottom bracket

[young Ed]

could i replace my lose ball bearing bottom bracket set up with a sealed unit like this

Cheers Ed

 

[biggs682]

cant see a reason why not just make sure you get the correct one

 

[PpPete]

or even the right one

OK we're assuming you are replacing square taper with square taper ? good move BTW - far better than any of the "modern" alternatives unless you are loaded.
First, carefully measure the width of the shell on the frame.
Is it 68mm? (as opposed to 70mm or 73mm) If so chances are it is standard english threaded (unless it is an old raleigh which is standard width but very slightly different thread)
Don't forget the drive side is left-hand threaded.
Sheldon has a complete database of all the old standards in case you have an odd-ball one.
Now you need to figure out the length of the spindle (easiest to measure with calipers) and whether it is JIS or ISO taper.

Oh yes and go for the UN54-55 rather than the UN25-26 - not much more £ and last a lot longer.

 

[compo]

Agree with @PpPete about the UN54-55. I fitted a UN26 on my hybrid that only lasted a few months. I have now fitted a UN55 and it just feels so much more solid and smooth. The UN55 also has a metal securing collar instead of the plastic found on many other units.

One problem I once had when replacing loose balls with a sealed unit on a different bike was that the sealed unit would not go through the frame. The rivet that secured the cable guide under the BB frame was protruding too far inside the frame and fouling the cartridge. 5 minutes with a dremel and grinding wheel sorted it without any problem.

 

[young Ed]

okay will start stripping whole bike soon just need to get the bike i use on road
also mum is planning to start cycling more on her years old German bike i would die for that frame a very light steely! so will give it a general maintenance/service to make sure it is ready for road
Cheers Ed

 

[400bhp]

good move BTW - far better than any of the "modern" alternatives unless you are loaded.

You mean like a Hollowtech 2 that are about £12

 

[Somewhere]

You mean like a Hollowtech 2 that are about £12

Not sure really. Can be very hit or miss at times with the reliability of ht2. Sometimes they last ages others barely 1k miles. If he went down this route be would need new cranks and probably the bottom b faced too.

 

[400bhp]

Not sure really. Can be very hit or miss at times with the reliability of ht2. Sometimes they last ages others barely 1k miles. If he went down this route be would need new cranks and probably the bottom b faced too.

20,000 miles in the last 3 years on Hollowtechs. I have replaced 3 IIRC.

 

[young Ed]

Not sure really. Can be very hit or miss at times with the reliability of ht2. Sometimes they last ages others barely 1k miles. If he went down this route be would need new cranks and probably the bottom b faced too.

why cranks and refaced bb?
if the ht2 is very hit and miss can any one recommend something more reliable?
Cheers Ed

 

[Somewhere]

why cranks and refaced bb?

Google is your friend!

 

[compo]

why cranks and refaced bb?
if the ht2 is very hit and miss can any one recommend something more reliable?
Cheers Ed

You wont go far wrong with a simple UN54 or UN55. Simple to fit and reliable in operation plus you can use your existing cranks.

 

[young Ed]

removed bolt on both sides of axle yesterday night and tried pulling cranks off with crank puller like this

and neither crank will come off! do i need a real bicycle crank puller like this

or what am i doing wrong?
Cheers Ed

 

[fossyant]

You need a puller like in the second photo but one that you can fit a big spanner to

 

[young Ed]

are they standard for all bottom brackets or do i need to get one of right diameter and thread?
Cheers Ed

 

[grimpeur]

the tool in the 2nd pic works fine- it is the Park Tools crank extractor. Although it may look small and not very strong, it is. You don't need anything else.