ORANGE P7 Aheadset fitting problem

[panantukan]

I wonder if anyone can help. I've got a retro P7 (96ish) and am trying to get a new aheadset fitted. The shop have tried about five 1 inch aheadsets to no avail. The problem seems to be that the inside diameter of the head tube is too large for the Aheadset, therefore meaning the outside surface of the Aheadset shell doesn't sit flush against the inside of the head tube, causing there to be play between the component and the frame.

Have u guys heard of this before?? It seems very strange to me. All of the older P7s are 1inch and I'm sure the bike shop would have tried a 1 1/8" if they though for some reason that would fit.

JD

 

[Andy R]

Is it the top or bottom bearing cup that is loose and was the headset that was taken out (the old one) loose too?
And how loose is it - is it just less of an interference fit than it should be or does it just drop in?

If four or five different headsets are all loose then one has to assume that the headtube is reamed slightly oversize or else ovalised - depending on how oversize (ie, not much, maybe .0015") then Loctite 641 would be your friend
Or see if you can get a deep insert headset and use that in conjunction with 641.

Any more than that and you're looking at shimming.

 

[Anthony]

There are two standards of 1" headset, one of which is for 30.0mm tubes and the other for 30.2mm tubes. The smaller ones are for cheaper, more mass-produced bikes, but could the headsets your LBS has tried be for the smaller standard? JIS rather than ISO, or something like that?

 

[Mossy]

I have a 97 P7 (same as 96 in many respects) I've just overcome a similar problem. JIS and ISO is likley to be the problem.

See my thread for further information that may be of use.

http://www.retrobike.co.uk/forum/viewto ... ight=mossy

regards, Mossy

 

[jimc101]

Have you tried measuring it with a caliper, as Anthony, there is the ISO and JIS standard, but would have though a decent quality frame would be an ISO.

Would go to a good LBS for their advice if it's ovalized

 

[Andy R]

There are two standards of 1" headset, one of which is for 30.0mm tubes and the other for 30.2mm tubes. The smaller ones are for cheaper, more mass-produced bikes, but could the headsets your LBS has tried be for the smaller standard? JIS rather than ISO, or something like that?

I completely forgot about JIS being 30.0mm as opposed to 30.2mm

.

Good point Anthony .

 

[panantukan]

Many thanks, I'll have a look at your other thread!!

 

[clownfish]

I do vaguely remember someone mentioning a problem with very early P7 headtubes going out of shape; hence the external strengthening rings (for want of better description) top and bottom.
Is your headtube 'plain' (constant external diameter) or does it have the external butting?

 

[panantukan]

Here's a pic - It's got the band around the top and bottom of the headtube. PS this is the old aheadset ie the one which is shot and can no longer be used. The bike shop said they've tried to fit several other units to no avail.

 

[clownfish]

yep - I'm sure its the JIS/ISO issue then as suggested above.