Headset probs...

[CTK]

I'm baffled...

Recently bought a 1" aheadset and I'm struggling to fit it...

Basically the bottom race that should press fit is loose on the forks, about 1-2mm of a gap around bottom of steerer tube.

I've tried it on 3 different 1" forks!

& its def. not a 1 1/8th headset as its too small...

Can anyone shed some light?




:?

 

[cherrybomb]

What forks?

 

[cherrybomb]

D'oh!

I should learn to read! :roll:

 

[CTK]

I've tried it on a set of groovy forks, and 2 diff steerers on a pair of Bonty forks (1 threaded and 1 ahead) Its not close on any of the steerers. I've also tried it on a set of 1 1/8th tange forks which it is too small for...

 

[Elev12k]

There are two types 1" headset. JIS and ISO. Maybe that is the reason? Do some Google'ling. I know there exact difference can be found somewhere.

 

[Elev12k]

Okay, from the ParkTool website:

One-inch Japanese Industrial Standard (JIS)
Common on many Asian manufactures bicycles, both road and MTB
Fork column outside diameter- 25.4mm (1")
Head cup race OD- 30.0mm
Acceptable head tube ID range- 29.75mm to 29.9mm
Fork crown race ID- 27.0mm
Fork crown seat OD acceptable range- 27.1mm to 27.2mm
Stem diameter at quill- 22.2mm

One-inch "Modern European" Standard
Many road bike and some MTB bikes
Fork column outside diameter- 25.4mm (1-inch)
Head cup race OD-30.2mm
Acceptable head tube ID range- 29.9mm to 30.1mm
Fork crown race ID- 26.4mm
Fork crown seat OD acceptable range- 26.5mm to 26.7mm
Stem diameter at quill- 22.2mm

 

[CTK]

Thanks very much for the info, was not aware there were 2 standards, could be possibly down to that then... I'm going to buy another headset and keep my fingers crossed!

 

[Elev12k]

CTK,

A 2nd thought: JIS is by far most common. It seems most likely your forks should be ready to accept JIS standard. JIS is the wider standard ...and you complain about the race fits loose :shock: From this perpective the JIS vs ISO theory seems a not so logical explanetion for what you are facing.

 

[one-eyed_jim]

A 2nd thought: JIS is by far most common.

That may be true numerically (I'm not sure), but most better-quality bikes - particularly those not made in the Far East - use ISO. My '92 Stumpjumper was JIS, but Bontragers, Ritcheys, Kleins etc. are all ISO.

CTK's problem is almost certainly that he has a JIS headset and needs an ISO.

 

[CTK]

The thing is that we're not really talking fractions of mm- Its at least 1mm- on different steerers too. The top cover (the bit that sits just below the stem or spacers) is actually a better, tighter fit than the bottom race!!!