Older Dawes horizon headset size

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ellietwed
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Older Dawes horizon headset size

Postby ellietwed » 13 Oct 2010, 9:31pm

Hi folks,
I have an old Dawes horizon that's in need of a new threaded headset but I'm unsure what spec I should go for. I'm unsure of the bikes age but early 2000 at a guess, it's got a 1 inch steerer tube. All advice much appreciated!
Many thanks
D

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gaz
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Re: Older Dawes horizon headset size

Postby gaz » 14 Oct 2010, 8:10am

You need to establish the stack height of your current headset. That's basically the height of the visible headset parts from the top of the fork crown to the bottom of the head tube plus the height of the visible headset parts from the top of the head tube to the top of the head set lock-nut.

The replacement headset must not have a larger stack height. Take particular care if you have a front brake cable hanger as part of your stack. You'll need to add that in to the height of the new stack.

Stronglight A9 is a great choice but has a fairly big stack at 38mm. Available in steel or alloy.
There'll be tarmac over, the white cliffs of Dover ...

ellietwed
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Re: Older Dawes horizon headset size

Postby ellietwed » 14 Oct 2010, 10:27am

Many thanks for the reply Gaz, much appreciated. It appears the headset has loosened and when attempting to tighten the upper lockring the steerer tube has threaded. Mind you it appears the lockrin has not had a lot of thread available to make any purchase on the tube. Theer is a cable hanger and a very think washer sitting above that. I'll measuer up and see whats available. I want to use the bike as a winter hack/commute bike so don't want to spend the earth on a erplacement headset and fitting.
Cheers again
D :)

Edwards
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Re: Older Dawes horizon headset size

Postby Edwards » 14 Oct 2010, 10:49am

The lock washer above the cable hanger is available in different thicknesses. If you use a thinner one it should have more thread's. Make sure the tab is in good condition.
Keith Edwards
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ellietwed
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Re: Older Dawes horizon headset size

Postby ellietwed » 14 Oct 2010, 1:37pm

Cheers Keith,
Now to find somewhere that can supply one !
I've had a dig about and found an interesting earler CTC post about someone in a similar predicament, if I need a replacement headset its gonna have to have a low stackheight to accomodate the washer and cable hanger, oh the joys...
All the best
D

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gaz
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Re: Older Dawes horizon headset size

Postby gaz » 14 Oct 2010, 2:02pm

Shimano 105 threaded is famed for a low stack height. But as it's only for a hack you might do fine spending less on something basic.

You could also consider replacing the hanger with a fork crown mounted uphanger. That will gain you a little more room for the stack.
There'll be tarmac over, the white cliffs of Dover ...

fatboy
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Re: Older Dawes horizon headset size

Postby fatboy » 14 Oct 2010, 3:02pm

I have a 105 headset on my Horizon (2004 model) which seems fine. I let an LBS fit it and it was the only threaded headset that they had.
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly

rjb
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Re: Older Dawes horizon headset size

Postby rjb » 14 Oct 2010, 6:21pm

The other problem you may have is that older Dawes frames were made to the jis headset standard, ie head tube of 30.0mm and fork crown race of 27.0mm. This is the size on my Dawes Galaxy of 1994. (Current iso standard is head tube of 30.2mm and crown race of 26.4)
New 1 inch jis headsets are very difficult to find now.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin, Raleigh 20, Falcon K2 MTB dropped bar tourer, Longstaff trike conversion on a Falcon corsa. :D

ellietwed
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Re: Older Dawes horizon headset size

Postby ellietwed » 21 Oct 2010, 5:34pm

Thanks again for all your advice folks, after inspecting the races etc I've decided to replace the 5mm spacer with a 3mm one to give my locknut some extra thread to grip. Should keep me going for a while longer !! :D

Jhpugh13
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Re: Older Dawes horizon headset size

Postby Jhpugh13 » 3 Oct 2018, 1:45pm

Hi I to am looking to replace the headset on my 1998 Dawes Equinox. It is also a 1" threaded but my local bike shop are having trouble getting the Crown Race that sits on the forks to fit properly!?? Any advice?
Cheers Jon Pugh

Brucey
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Re: Older Dawes horizon headset size

Postby Brucey » 3 Oct 2018, 3:28pm

it is probably takes a JIS sized crown race (27.0mm) rather than an ISO one (26.4mm)

The normal method of dealing with this is to machine the crown race seating to 26.4mm. Of course you can open up the crown race instead, but this just postpones more misery the next time the headset needs replacement. JIS headsets are the exception these days.

BTW if you want a shallow stack height headset, the Tange Passage is worth a look; it can be used without the tab washer (provided you are happy to tighten it using two spanners) and then the stack height is that bit less; about 28mm without the washer.

I also advise that you use loose balls in place of the clipped ones; this gives a stronger headset.

cheers
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peetee
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Re: Older Dawes horizon headset size

Postby peetee » 3 Oct 2018, 10:22pm

Brucey wrote:it is probably takes a JIS sized crown race (27.0mm) rather than an ISO one (26.4mm)

cheers

Just this week I have changed the forks in a circa 1990 Dawes shadow. I still have the old ones and will check the crown seat size tomorrow.
Winter had arrived in the land of Kernow. Along with it came wet roads and cool winds.
“Oh, my wheels and coupling rods!” Peetee exclaimed.

peetee
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Re: Older Dawes horizon headset size

Postby peetee » 5 Oct 2018, 9:26pm

Just this week I have changed the forks in a circa 1990 Dawes shadow. I still have the old ones and will check the crown seat size tomorrow.


I can confirm it is 27mm
Winter had arrived in the land of Kernow. Along with it came wet roads and cool winds.
“Oh, my wheels and coupling rods!” Peetee exclaimed.

Brucey
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Re: Older Dawes horizon headset size

Postby Brucey » 5 Oct 2018, 9:35pm

FWIW although we presently refer to the 27mm crown race dia. as 'JIS' this size is actually the traditional British size; when threaded 1" headsets (as we know them today) were still a fairly new idea crown races were nearly always this size on british bikes of the 1950s and 1960s. If you examine an old bayliss-wiley or TDC headset it will most likely have a crown race of this sort.

cheers
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Chris Jeggo
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Re: Older Dawes horizon headset size

Postby Chris Jeggo » 5 Oct 2018, 11:16pm

If it surprises you that a 27mm crown race dia. is a traditional size on British bikes of the 1950s and 1960s, then note that 27mm exceeds 1 1/16 inches by a gnat's wotzit (half a thou in this case).