1983 Raleigh Record Sprint Headset Woes, Please Help!

[Jimmy S1]

Hi,

I'm currently restoring a MK1 Raleigh Record Sprint. I am now trying to rebuild the bike after having the frame powder coated, but I am really struggling with the headset and wonder if you guys might be able to shed any light on the situation?

The original headset (which according to the 1983 Raleigh brochure is a Tange MA60) is shot and I've bought a Tange Passage (1" ISO) to replace it. However, due to making some incorrect assumptions I think I've bought the wrong headset and selecting the correct one is proving to be a bit of a challenge!

As far as know there are four things to get right when selecting the correct size of headset: stack height, crown race ID, frame cup O.D. steerer tube diameter/ thread

Starting with stack height: I no longer have all of the old headset to use as a reference (please don't ask!) I have therefore calculated the stack height by measuring the full length of the fork steerer (including the stepped part that the crown race sits on)[. This measures 206mm.

I've then measured the full length of the head tube on the bike this measures 171mm

Therefore 206 - 171 = 35mm stack height? please correct me if I'm wrong!

Moving on to the Crown race. The step at the bottom of the steerer tube that the bearing sits on measures 26.8mm in diameter

The ID of the frame head tube is 29.95

The steerer tube is 1" in diameter and the ISO threads of my new headset seem to fit well.

Now, the problem with the ISO headset is that the crown race ID is measuring small 26.3mm (should be 26.4) There is no way that this will fit on to the stepped part of my steerer tube at 26.8mm the Frame cup ODs are 30.3 (should be 30.2). I have had a go at pressing these in, again, these are simply not going to go in!

The stack height is 30.2mm so I presume I'll be OK (I appreciate I may need a spacer)

I'm starting to think that the bike should have a JIS headset and I would happily buy one, however, the ID of a crown race for a JIS headset is 27mm,which would make it a loose fit on the stepped part of my steerer tube. (26.8mm)

I’ve had the frame fork blasted prior to powder coating, so it could be that I’ve lost a bit of material on the steerer tube.

According to Sheldon B, the threads are the same TPI on both ISO and JIS.

My thoughts are that I have three options:
1. Buy a new JIS headset and hope it fits! (any suggestions of headset appreciated)

2. Buy a new JIS Tange Passage headset(which they do manufacture), use the frame cups from that, machine the stepped part of my steeer tube down to 26.4/5mm and use the ISO Tange passage crown race, creating a kind of ISO/JIS hybrid. (I have access to a lathe)

3. Send my frame and fork to a machine shop and have the frame reamed and fork steerer turned down so that the bike will accept a standard ISO headset.

Any thoughts much appreciated!

 

[The History Man]

Machine the cup ODs cut a slot in the crown race or take .2 off the internal dia?

 

[mattr]

cut a slot in the crown race

AFAIK It's a loose bearing headset.

 

[Jimmy S1]

Thanks for the response guys, it's a cage ball bearing headset do not sure that cutting a slot would work?

I had thought about machining the cups, bit the upper one is the bearing race so is hardened and will probably kill my dads lathe!

I've read a bit more about mixing and matching of ISO and JIS components and feel a bit more relaxed about machining my fork to accept the ISO crown race and buy the corresponding Tange headset in JIS form for all other components. That way the frame doesn't need to be touched.

Still a bit confused about stack height though!

 

[Midlife]

That's really odd.... Have you got the frame number handy?

 

[torqueless]

Re:

..and just to be clear, you are measuring diameters on bare metal? i.e. metal that has not been powder coated?

 

[Jimmy S1]

Re:

Like an idiot, I didn't take a note of the frame number before powder coating! I've Just looked and I think I can make out
YC8
06B (or it could be YC8 06. There is also an 's' stamped at 90 degrees to the above number

It could be a postcode! I remember having my bikes stamped by a person who used to come in to school and security stamp your bb tube with your postcode in the 1980s

I am measuring bare metal, the powder coasters have done a cracking job masking everything off.

 

[Midlife]

Raleigh were anal about numbering frames as they were run by accountants,. Is there a number under the seat bolt running vertically ?

AFAIK all Raleigh frames leaving Notingham / Worksop would have bog standard English / ISO kit.

 

[Jamiedyer]

A while back when I was putting the Mercian back together I wanted to just knock it back roughly one weekend to just try some components. I wanted to try my bars and stem and didn't have my headset at home, which is a Mercian stamped Tange headset, so I decided to use another Tange one I have new in a box. I found that the lower race was a smidge too small and also the very top nut just wouldn't go on.
I thought I must have an issue with my forks.
Then I remembered that the one I was trying to use was a BMX one for my old 79 Mongoose and they have that slight difference, took a while to remember but once I got my other one from my inlaws then bang, it fit fine first go.
So just double check, maybe take it to the local shop and try some old ones they have lying about, just in case like mine that your headset is the odd one out.

Jamie

 

[Jimmy S1]

Re:

Thanks for the advice Jamie, will try to pop to my LBS over the wknd. Think I've found the frame number looks like NG300036 there may be a 1 at the end too! (Numbers are so faint under the powder coating)