27mm Crown Race for an oldish Raleigh - can anyone help?

[casper-d]

Hello - I wonder if anyone can help, although I am not sure if I have posted this in the right place..

I am in the process of rebuilding an 80s Raleigh town bike. However the lower crown race on the forks has pitted, and I haven't had any luck on finding a new one. It has 27mm internal and 37mm external diameters, respectively.

If anyone has any ideas where I might get a new one I would be very grateful to know.

Many thanks,

Casper

 

[fossyant]

You'll need to buy the whole headset assembly - you don't get any bits individually.

I.e. frame cups, bearings and upper and lower crowns

1 inch headset, the only worry will be the stack height - i.e. how much steerer you have. Stronglight cheap, but seals rubbish. Shimano 105/Ultegra's can be got for about £30 - then they need fitting.

 

[PapaZita]

How accurately did you measure that 27mm? The usual dimension is 26.4mm, so it's possible that the crown race from a standard 1" headset will not fit. I've been caught out by this when I didn't realise that I was trying to replace a JIS (27.0mm) crown race on an old bike.

As always, Sheldon Brown has all the information.

PZ.

 

[casper-d]

Fossyant and PapaZita - thank you for both of your replies.

It will be a shame if I can't get just the part I am after. After all, all of the rest of the headset is in good nick having cleaned up well. I did go into Holdsworth yesterday and the helpful guy there also said that it would be hard to get just the crown race, but suggested that, if I looked everywhere, it might not be impossible!

PZ - I measured the crown race with some digital callipers and it is 27mm. Thanks for the SB link. I have looked at the page quite a bit recently! Tomorrow I will measure the other parts.

Thanks again, Casper

 

[casper-d]

Hello again,

I have looked at the SB headset dimensions link and I can't work out the exact type of headset I have! Could someone more knowledgeable than myself please have a look at the pictures below and offer some kind advice? Many thanks!

25.4mm OD fork steerer tube

27mm crown race seat

27.3mm ID lower head tube cup

40.6mm OD lower head tube cup

37.7mm OD upper head tube race

26.7mm ID upper head tube race

 

[PapaZita]

You have a one inch steerer tube (25.4mm), and a 27.0mm crown race seat. The other measurements aren't so useful, as the only dimensions that are standardized are the interfaces between headset and frame. The missing measurement is the inside diameter of the frame tube, for which you'll need to remove one of the headset cups.

Fortunately, knowing that it's a 27.0mm crown race is enough to narrow down the choices. From Sheldon Brown's table, the only standards to use 27.0mm are JIS or Italian. From your description of the bike Italian seems unlikely. It's almost certainly JIS.

I reckon your best options will be either to find a JIS headset, or convert to the modern ISO standard. I'm not sure how easy it is to find JIS headsets. I went for the conversion option. A good bike shop will be able to reduce the diameter of the fork crown race seat to 26.4mm and skim a little bit of metal off the head tube to open it up to 30.2mm.

PZ.

 

[fossyant]

1" headset.... you need to buy a new whole assembly, believe you me..... very common on older frames (3 of my 4 bikes use the older headsets).

You'll spend an age trying to get a match...just not worth it. I have 2 high level frames running shimano cartridge headsets, brilliant. You can get a 105 one for somewhere around £20 - Dura Ace are about £50.

Once fitted you'll only ever need to change the cartridge bearing (standard) but it's near on impossible to find just bearings, so you buy the whole lot, just fit the bearing you need, and keep the rest as spares.. With cartridge systems, the races (the bits that fit the frame) don't wear.

 

[fossyant]

And, the old headsets were poorly sealed.........

The other option, is to fit loose bearings to the pitted race, rather than the caged bearings - you'll need to add a few more bearings, but this will get over the clunky feeling...it's a bodge, but may just work, especially if the bike's not that 'mission critical'....... loads of grease.......

 

[PatrickPending]

i had a 105 headset fitted to my 1974 carlton which I use for commuting as the bearing race was pitted like yours - one thing to watch - the locking nut on the 105 is a fairly poor alloy - gave way 3 months in. Replaced with a steel one - no more problems.

 

[casper-d]

Thank you once again for all the replies - they are extremely helpful.

There is some difference in the diameters of the head tube races, I presume this helps to get a good tight fit into the frame tube. Nevertheless, I think that based on the above advice and the SB site I am confident to say I have a JIS headset My only worry is that on the SB site it says these headsets are normally found on "Older or lower-quality bicycles from Asia" - yet my bike is a Raleigh. So shouldn't my forks have 26tpi, rather than 24?!

It is all slightly confusing !

30.06mm OD head tube lower race (lower cup??)proximal edge

30.29mm OD head tube lower race distal edge

29.96mm OD head tube upper race proximal edge

30.03mm OD head tube upper race distal edge

 

[Joe24]

Is that digital measurer thing your new toy?

 

[fossyant]

Don't precision measure it - it's a 1"........

 

[fossyant]

Is that digital measurer thing your new toy?

£8.99..or so credits........

The Aldi system..........next Thus............. young Padawan.....this Jedi will be purchasing one for that amount of credits....... ...just need a star fighter to get me there..........

Just something else to add to the tool box......

 

[casper-d]

"Is that digital measurer thing your new toy"

Oh dear. Someone realised! Sincere apologies. I am really sorry about the blatant posting of my new silver measuring device I have always wanted one for years... how sad its that?! And now I have one...

So, to conclude, I have a 1"er.. no jokes, the measuring device confirmed it!

I have had a search for the Shimano 105 headset, but not found it in stock anywhere yet.

Thanks again