[Closed] My latest hare brained scheme

It's your face, crack on 😉

Forks, you say?

Sorry, I haven't got the tine to think of anything witty to say.

re glue the dropouts/brake mount on

Geoff, ever thought about what holds dropouts/brake mounts on to On one, exotic, Pace carbon forks?

Deeez r' trendin' a da mo'

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Ben? is he gentle? ask for a discount?

No, Ben is a real rat.

Just to keep you on your toes, I think Brompton have quite short rake forks. So that needs to be taken into account too. Too much rake will lead to right twitchy steering.

This sounds like a recipe for toothlessness or a serious head injury.
Why not just make them out of Papier mache and post a before, during and after video.

You're so funny 😐 try thinking, if you can.

Thanks Brant, more twitchiness not good.

Wo tabout, this.. angle grind the centre prong out and weld some lugs on the end, a jubilee clip for attaching bars and job, is jobbed.

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nah it one of these he needs ...... bromptons are only little.

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needs a front disc

For better braking? As an alternative can you still get ceramic coated rims? Back in the day they made a fantastic difference to braking especially in the wet and would maybe be a more practical solution.

Drill a couple of holes in your fork and use a couple of nuts and bolts to attach a flat mount brake on there. Sorted 🙂

make a mount out of a spoon and carbon wrap it on ?

Make it a fixie and you'll not need a front brake.

Fwiw

I'd be nervous of most alloy steerers for threading that I've seen (the one on my roadie doesn't look like the most robust material). Cannondale might have threaded them 25 years ago but I reckon they would have been a fair bit thicker then.

Do they internally "butt" carbon forks? If so you could have a thinner leg end to contend with post cut that needs some beefing up. You may know better than i.

One other controversial alternative approach. If you could find a suitable donor fork could you get/make up a crown+steel steerer then shorten the legs from the top and fit/refit leaving disc mount and dropouts in place?

RB ceramic rims...20 years ago in 700c and 26" maybe!

GD your last solution would be ideal but I could spend forever waiting for something.

Pretty sure Cannondale did thread theirs, and, think about it, steerer diameters and thicknesses were the same then.

Are you suggesting threading carbon?

Anyway I got a pair of Suntour forks for £10. The weight will be offset by my new rear rack, 140gm of chinois aluminium 😀

threaded alloy steerers of days of yore were thicker.

cannondales often had oversize forks even.

cut down some carbon or aluminium forks and re glue the dropouts/brake mount on

Glue, eh? Surprised nobody's tried that before, what could go wrong?

Glue, eh? Surprised nobody's tried that before, what could go wrong?

Glue could de-bond, but it's not a new thing, look at any number of carbon forks (On-One, pace, exotic are all glued). Lotus actually glue the elise chassis rather than weld as it's stronger, along with several superbike manufacturers bonding their frames.

And carbon fibre is about 30% 'glue' itself.

Lotus do it - so it must be robust, right

Lotus do it - so it must be robust, right

CCM use it in their MX bikes too.

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Gluing is fine if the design was based on glue, like the Elise chassis. I don't think it would work as well trying to glue a standard mild steel chassis that was designed to be welded.

Gluing is fine if the design was based on glue, like the Elise chassis. I don't think it would work as well trying to glue a standard mild steel chassis that was designed to be welded.

True, but then most forks with carbon elements are designed to be glued together.

what about a steel Pace steerer with a bolt on/in crown? Marzochhi Bomber crown and steel steerer?

Old Alan and Vitus CX and road bikes has 1" threaded aluminium steerers.

trail_rat - Member
threaded alloy steerers of days of yore were thicker

How? A 1 1/8 headset screws on the outside, a 1 1/8 stem fits inside?

No, Ben is a real rat.

Hey!

Cut-down Pace forks would be very cool - might not fold that well because of the wider crown, and you'll need a fitting for the handlebar catch, but they'd look brilliant.

You can use a threadless headset on the Brompton if you use a USE Ring-Go-Star.

I built a double disc for a Brompton once, that was silly...

Or if you just want something a bit better than the rim brakes, how about a drum? Greenspeed used to make a special narrow drum for Bromptons, not sure if that's still available, but the standard Brompton forks are also persuadable out to 100mm for a standard drum.

Interesting. I had a SA drum, not that powerful, heavy.

Ringostar could be a winner too.

Yup I wondered if the width.of the fork might be an issue, I'll check it all out when I return form this trip.

Cheers!

cynic-al - Member
Interesting. I had a SA drum, not that powerful, heavy.

Depends which era it was. I find they work much better if you use good cables, ie incompressible.

As for weight, I reckon you could shave quite a bit off in a lathe without hurting them.

Four candles?

Aren't we over complicating the whole issue here? Why not just get a disc mount professionally welded onto the existing fork? Wouldn't cost much.

Brian, a recent one. It's 500gm over a disc brake/dynohub shitmano set up. I don't have a lathe.

PP - STD fork is 70mm OLD so disc would foul fork leg.

Well, errrrrrr, yes?
CCM use it in their MX bikes too.

Glue can be very useful stuff if an assembly is designed to use it, but it's probably not wise to point to CCM as a shining example of build quality...

cynic-al - Member
Brian, a recent one. It's 500gm over a disc brake/dynohub shitmano set up. I don't have a lathe...

Nor do I, but as a fellow bodger you may appreciate how I plan do do just that.

Remove the axle and bearings, run a big bolt through it and attach to my drill press and spin it up.

I was planning using abrasive paper glued to a stick rather than a cutting tool just to minimise the effects of loonie H&S type incidents. 🙂

There's a lot of meat on the rhs flange for a start, and I reckon the drum could do with a few big holes on the vertical parts (we used to do that with motorbike brakes to improve cooling), then notch the flanges between the spoke holes.

The brake plate could be drilled out extensively or part removed. The structural part is between the pivots, the rest is just to keep the weather out.

The brake shoes could handle a few holes through the webs and removal of any metal not actually supporting brake lining.

Then there's the brake reaction arm. I've seen less metal on a full sized motorbike one. TY Yamahas were dead light - I may even still have one rattling around somewhere. Remove the arm and replace with a light alloy one.

Finally for more power I'd be tempted to spend some time dressing the brake cam.

I could take it to a mate and get him to do it "properly", but where's the fun in that?

Have you ever tried sandpaper/Emery on aluminium?

You have too much time on your hands...

cynic-al - Member
Have you ever tried sandpaper/Emery on aluminium?

It's how we got motorbike rough cast crankcases to a mirror finish back in the days before diecasting. It did take time, but the end results were very satisfactory.

Because cannondale threaded alloy steerers were 1 1/4" OD with relevent headsets to suit

Talking of steerers, the threadless steerers I've seen all look a bit on the thin side for threading, even the steel ones.

There's a quick and easy way to make a fork.

Get an old suspension fork with clamp on legs. These were either cheap BSO jobs or early mtb suspension. Most have a threaded steerer. That gets your fork crown and steerer sorted in one hit. It also lets you use 100mm OLD hubs.

Then for fork legs, find an old segmented fork with round legs (eg an Inbred) and cut the legs off.

The diameter of the fork legs is very close to the diameter that fits the above fork crown. Clamp them in and you're good to go.

The offset may be wrong, but that can be fiddled with by reversing the fork crown.

Trail can be altered by working out what length of fork leg to use. If you leave a bit extra in you can adjust up and down until it feels right, then cut to suit.

I think have an old fork crown and steerer if you want to try it.

Alternatively, you can use a later type fork which has bonded stanchions. Then cut down a set of sliders to suit. It would be heavy for a wee folder.

I did that here to make an adjustable rigid fork experiment with trail and head angle for fatbikes.

I used seatclamps to clamp the legs, and had an internal spacer so it couldn't collapse on to the tyre. click on this link to see the process.

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trail_rat - Member
Because cannondale threaded alloy steerers were 1 1/4" OD with relevent headsets to suit

Yes that's right. STD 1 1/4 stems tho no?

Brian you're basically admitting your sandpaper idea is time consuming even for polishing, and you want to use it for material removal?

I see your idea, but if you mean by "segmented" forks modern CSU style ones the the "stanchion" part is way larger diameter than what you'd find on old cheap suss forks (28.6mm etc like Judy's have a price premium I think, I guess there are RSTs).

the threadless steerers I've seen all look a bit on the thin side for threading, even the steel ones.

In the early days of threadless, even the late 90s, steel steerer were the same guage for threaded.

https://www.flickr.com/photos/7693620@N05/shares/pCh369

That doesn't look at all lopsided... Well done...

Where do the spoons come in?

Assuming Daffy is joking, it's intentional

Good job! It didn't go so well when I once tried doing that with a titanium fork...

Ooh thanks.

It's well dented, I'm hoping this won't be an issue. If I fill them in at least I might forget about them 😀

I never know whether to admire you or just take out life insurance on you when you do a project 😉

I admire the endeavour, and the ambition to save money on toothpaste 😉

What's the tyre clearance like none disc side?

Ta.both, tyre clearance will be good, the dork is wider than normal now.

I've got to build up a wheel as the original won't fit - and sort a brake mount and get it brazed on. Hopefully won't take me long.