SOS - Help needed with Cannondale fork & headset

For discussions about bikes and equipment.
Post Reply
LuckyLuke
Posts: 374
Joined: 10 Jun 2010, 11:54am

SOS - Help needed with Cannondale fork & headset

Post by LuckyLuke »

Hi folks, am writing on behalf of my pal John. He has ?1996 Cannondale mountain bike. Name unknown.
It's a rigid frame and has a threaded rigid fork with a threaded headset.
The headset has been loose for a while and the threads have worn on the fork, so the locknut can't be tightened.
The fork steerer tube and headset are larger than I'm used too, having only worked with 1" or 11/8" forks and headsets.
The headset cup outer diameter is ~34mm, measured by my vernier callipers.
The frame headtube inner diameter is ~36.5mm, to a depth of ~9.6mm, then there is a slightly narrower metal sleeve.

Any one have any advice? Anyone with a Cannondale MTB who's encountered this problem before.
We have an unthreaded steel fork with 11/8 steerer and a 11/8 threadless headset.
Are there shims available that could fit in the frame headtube?
OR
Could the fork threads be recut to enable the existing headset to be fitted? The headset is not pitted so potentially could be resurrected.
OR
Does anyone know if forks and headsets that fit are available to buy off the shelf?
OR
Is it an uneconomic, unpractical repair?

Thanks all, much obliged for any help or ideas.

Best wishes,

Luke
Brucey
Posts: 44516
Joined: 4 Jan 2012, 6:25pm

Re: SOS - Help needed with Cannondale fork & headset

Post by Brucey »

it might be a 1-1/4" threaded headset...? You can check dimensions against Sheldon's headset crib sheet.

Cannodale have long used, uh, 'interestingly sized' headsets. You might find something useful listed here

https://qwertycycles.co.uk/collections/headsets

Repair options include;

- If the steerer is steel then the part can always built up and threads recut. But this is contingent on finding someone with the correct die (or being able to make one from an old 'all hard' adjusting race from a similar headset).
- adaptor sleeves can be made up to allow fitment of a 1-1/8" headset/fork
- various 'bodgy' approaches can be used to allow the extant headset parts to be reused, including use of chemical metal to bond the headset adjusting race/locknut in the right place. Obviously some of these won't allow subsequent adjustment in the normal way.

one bodgy approach that might work if it is only the locknut that won't grip is to shorten the head tube of the frame and this exposes more (hopefully undamaged) threads on the steerer. Likewise a different headset in the same fitting might be 'lower profile'. A locknut can be machined round on the OD, split and then fitted with a clamp (eg a seat binder clamp) so that it stays in place/can be tightened even on damaged threads.

is it 'economic', probably not. Is it 'worth it'? Dunno. It depends how much you like the bike really.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
User avatar
531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: SOS - Help needed with Cannondale fork & headset

Post by 531colin »

If this is an inch and a quarter steerer with one sixteenth of an inch wall thickness, then a length of inch and eighth steerer will fit perfectly inside it, and can be brazed in. (drill a couple of holes to introduce spelter, I would overlap the 2 tubes a couple of inches ) Then you can use the existing bottom race (which will be a bugger to replace anyway) and all the top race gubbins from an inch and eighth threadless headset, with a new inch and eighth ahead stem, star fangled nut etc. You will need to sleeve down the top of the head tube to take the smaller headset cup.
If you want to re-use the existing inch and a quarter top adjusting race, will any wear in the threads show as slack in the headset which you can't adjust out?
Somewhere among all the junk, I have a headset where the adjusting cup has a pinch bolt to nip it up on the steerer thread, there was no locknut; but its inch. I've also got a threaded inch and eighth "repair" headset for use when the steerer thread is damaged; it has a sleeve with its own thread which goes over the damaged steerer thread.
Inch and a quarter quill stems must be getting a bit thin on the ground!
User avatar
531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: SOS - Help needed with Cannondale fork & headset

Post by 531colin »

Oops! just re-read the OP....if you have a spare inch and eighth fork, headset, etc knocking about, the easiest job is to buy headset reducers....https://www.sjscycles.co.uk/headsets/1-14-to-1-18-inch-headset-reducers-alloy-black/...other brands exist.
As long as the fork length (axle to crown race seat) and offset are not too different, the steering should be OK with a different fork.
LuckyLuke
Posts: 374
Joined: 10 Jun 2010, 11:54am

Re: SOS - Help needed with Cannondale fork & headset

Post by LuckyLuke »

Hi Colin, Hi Brucey,
Many thanks for your replies. Apologies for my delayed reply.

Brucey, thanks for the link to Sheldon's Crib Sheet, it looks like a 11/4 threaded headset after all. Thanks also for the Cannondale headset link. Pal John has 3 'dales so this will no doubt come to his rescue one day.

Brucey, Colin, lots of great hacks there, most were new to me so thanks for sharing. The fork and steerer are alu, and as Brucey described the threads have gone, though the ones lower down are good. Unfortunately the headset was lowish profile anyway, and as Colin writes 11/4 threaded headsets are rarer than a Dominic Cummings' apology.

Given the age and material of the original fork, and our lack of skill and equipment, we've gone down the headset reducer route.
Thanks for the link Colin. John has ordered 11/4 to 11/8 headset reducer shims and we'll have a go and fitting these, with a 11/8 threadless headset and fork.

Many thanks both for your help!

Best wishes,

Luke
Post Reply