Identifying bearing size

wayne ashford

Hi, can anyone help me identify the stem size for my forks please as i'd like to replace the bearings, there is a little play in them.

Could i try nipping up the headset nut a little to take out the play or do i run the risk of siezing the bearings?

The bike is a Giant OCR (3?) compact of unknown age but from pictures ive seen it looks like a 2000/2001.

proto

Edit: ooops. Wrote a long reply all about headset bearings, then realised it didn't answer your question :oops:

Take the forks out and measure the steerer tube. I'll either be 1" or 1-1/8" in diameter. You might try nipping up the bearings a tad, but bearings are better loose than too tight. So proceed with care.

proto

Here's my original reply, which might help you select the correct bearing if you do need to replace it/them.

I'm assuming it's a cartridge type headset, 1-1/8". If so, take one bearing out. The bearings are defined ( for this purpose) by diamter, internal angle on one end of the inner race, and the extrnal angle on other end.

If you're lucky it will have the size and type lasered on the side. If the bearing is not marked, then measure the OD with a caliper or micrometer, which will identify it.

There are three main types, none of which are interchangeable..

1) What is often called 'Cane Creek' standard which a 41.0mm x 36° (int.) x 45°(ext)
2) 'Campagnolo' type which is 41.8mm x 45° x 45°
3) 'TH' standard which is 41.5mm x 36° x 36°

Type 3 is not that common.

Note that most brands, FSA, Ritchey, BBB and so on, make headsets in both types #1 and 2 above. You'll struggle to find a type 3, but FSA do make one - No16TH.

Interestingly, Tien Hsin (the TH in #3 above), a Taiwanese company seem to make just about everyone's headsets. They also own the FSA brand.

wayne ashford

Thats very helpful indeed, many thanks.
Giant list the 2006 bike as having Cane Creek IS headset, whether the 2000 bike does remains to be seen but i'll whip the forks out and have a look.
Cheers
Wayne