A forum for owners of Yamaha TTR250 trail and enduro bikes!

Smoke n ride · Newbie

Supermoto wheels?

krum downunder · Veteran Member

Hey Mate, just type Supermoto into the search on this site, it gives you just about all the info there is on the subject.

TTRfan · Super Guru

A good thread here - http://ttr250.activeboard.com/t44801045/supermoto-conversion-very-easy-alternative-wheels/

The axle size is determined by the inner diameter of the wheel bearings rather than the wheel's hub. If you find a pair of wheels you fancy check that you can get wheel bearings that have the outside diameter of the hub's bearings and the id of the TTR axle wink

Be aware that you may have to get new spacers turned up to fit the TTR swing arm and forks especially to get the offset on the rear wheel correct to accommodate the TTR's sprocket and brake disc.

Brian

PS Welcome to the forum biggrin

robs · Senior Member

Thanks for the tips Brian, I started a similar thread then noticed this one got updated so deleted the other one.

I just bought some wr125 17" supermoto wheels off ebay: www.ebay.co.uk/itm/YAMAHA-WR125-FRONT-REAR-17-SUPERMOTO-WHEELS-2012-model/192555174452%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 - I tried searching but couldn't find the axle size so will have to wait until they turn up before ordering the correct bearings. Other than making some spacers I'm hoping they more or less work as-is with regards to the disk brakes.

The listing mentions 110/70 front & 130/80 rear, does anyone have any supermoto tyre recommendations?

Cheers,

robs · Senior Member

Minor update: Wheels arrived today - only did a test-fit of the front one before dropping them off at a tyre fitters to get the tyres and tubes fitted (lazy, I know). The front axle is the same size as the TTR (so with any luck the back one will fit too) and the hub looks the same but isn't, the disk mount on the WR has the same hexagon formation but the bolt holes on the WR are further from the center of the wheel, meaning that I can't just fit the original TTR disk. If the disk fitted, even then, the caliper would need padding out.

I'm not really sure what the best way to work out required spacer size is. So far my ideas are to either wrap tape around the wheel and/or to make some test ones out of wood or cardboard before getting some made up at a machine shop.

After the spacers are sorted I'm going to need to build a caliper adapter too. I think I'll start by building a template out of card and then again, make one out of wood to provide as a template to a machine shop.

If anyone has any better ideas and/or advice I'd be interested to hear it.

Moo · Senior Member

Only other option is to get the WR rims laced to TTR hubs

robs · Senior Member

Moo: I wondered about doing that but it'd significantly increase the cost (buying two sets of wheels, basically) but on the other hand in hindsight, it'd be the easier way to go.

I've just built a prototype caliper bracket (it looks awful but is functional). My first time working with metal - I used an angle grinder, a couple of clamps, a drill, and a tap to thread two of the holes. I plan to make a nicer one when time permits.

Someone reliably informed me that the bolts in these photos (8.8) have bad shear strength so I'm going to replace them. The washers are temporary until I get the new bolts which I'll also cut to length.

Both front and rear axles are the same as the TTR but new spacers are required, so that is the next job on the list.

TTRfan · Super Guru

Good work Rob! smile

robs · Senior Member

I'm thinking about remaking the bracket with stainless steel, does anyone know much about materials? Would 5mm stainless still be strong enough in this application?

Cheers,

robs · Senior Member

Finally got the spacers back from the engineers and stuck them on the bike. Two of the four are pictured:

Next task is to build a nicer caliper bracket.

Dan-in-a-Van · Veteran Member

Welcome to the Supermoto club. I got my membership thanks to the hard work of a previous owner ;)

robs · Senior Member

Nice bike Dan, out of interest what did you use to paint your tank and how hardy is the paint?

After a first ride today I'm finding the front suspension could do with being made a bit more firm, do you find the same with the smaller wheels?

Dan-in-a-Van · Veteran Member

The tank was painted in a weird rubberised paint when I got the bike so I just sanded it down to give the paint a key and rattle caned it. The paint was the cheapest primer and matt combo I could find. I'm pretty sure if I splash any petrol on it when I'm filling up it'll lift off :(

I've got the opposite problem with my front end. The forks are off a YZ so they're pretty stiff but they come in handy for off-roading. Despite the moto wheels my bike has got hybrid tyres on it so I still use it for green lane exploring .

robs · Senior Member

Nice! Did you do the same for the rest of the plastics? edit: oh, yes, looks like you did.

I'm considering trying the tank-dye method: https://www.youtube.com/watch?v=O0s6E0y8O2g - I've bought the dye, just need a big enough tank.

I went for a proper test ride yesterday and appear to be having an issue where the bike pulls to the left when braking. I've just tightened up the front axle to see if that fixes it. If not I wonder if the bracket is flexing during braking, although I'd be surprised it that was the case, although it's obviously pretty difficult to tell when riding the bike.

The new disk on the front wheel looks to be around 4.75mm thick. I've measured the old disk and it's 4mm thick. The result is that the front wheel doesn't spin freely, although it does spin about a quarter to one half of a turn. Presumably I just need to wait for the pads to wear to match the disk? Does anyone know if this is OK, or is it suicide? I'm a bit weary about how much of the pads will be left once they've worn to fit the disk..

-- Edited by robs on Friday 3rd of August 2018 10:52:56 AM

-- Edited by robs on Friday 3rd of August 2018 10:53:56 AM

Dan-in-a-Van · Veteran Member

The brake piston should adapt to suit the thickness of the disc. Is the piston seized? When I've fitted new discs on other bikes I've used a g-clamp to push the piston fully back into the caliper and used a bit of copper-slip to help it keep moving.

If the wheel is only spinning free for half a turn then either the disc is warped or something else isn't running true. It sounds like you need to check the front wheel is sitting square with the new spacers.

ttboof · Super Guru

Dan-in-a-Van wrote:
The brake piston should adapt to suit the thickness of the disc. Is the piston seized? When I've fitted new discs on other bikes I've used a g-clamp to push the piston fully back into the caliper and used a bit of copper-slip to help it keep moving.

If the wheel is only spinning free for half a turn then either the disc is warped or something else isn't running true. It sounds like you need to check the front wheel is sitting square with the new spacers.

Also check that you haven't over filled the resavoir if the fluid has been pushed back once it hits the cap it can't go any further

Should be able to check height with the sight glass

robs · Senior Member

dan-in-a-van: I've checked the axle is straight and the hub is straight. I bought a new front disc because the one that came on the wheel was bent but there is still a slight wobble, even with the new disk - only about 1 or 2 milimeters, I'm not sure if this is expected or what could cause this wobble but I'm assuming this is why the wheel doesn't spin freely. Is this a major issue? Also, do you live in a van? I ask because I'm building one at the moment

ttboof: I hadn't considered that and I'll check it later today, thanks for the tip.

Dan-in-a-Van · Veteran Member

I only live in my van occasionally.

robs · Senior Member

Nice van Dan.

After further investigation it looks like the TTR caliper just isn't designed to work with the large (diameter, thickness) disks. I've noticed wear to the caliper bracket after my test ride so at this point I either need to find a small disk to fit the WR hub or I need to get a caliper that is capable of working with the larger disk.

Either way I'll probably need to get new front spacers made up because I doubt the alignment will be the same in either case.

Does anyone know if TTR and WR calipers are interchangeable?

-- Edited by robs on Tuesday 7th of August 2018 05:26:43 PM

Dan-in-a-Van · Veteran Member

I can't check until the weekend but I'm pretty sure my front caliper has got a modified bracket like the one you made. I'm not sure if the front wheel on my bike is standard? The previous owner might have put a YZ wheel on it to match the forks or used a YZ caliper. Maybe someone can tell what my combination is from this photo?

Wheel rim.jpg

robs · Senior Member

Dan: at first glance that doesn't look like a TTR caliper to me, but I could be wrong. I'd definitely be interested in seeing photos of how your caliper is mounted.

I've tried to find a 250mm front disk that'll fit my wr125x front rim that has the slightly wider 6 bolt spacing than the TTR without luck.

Custom made discs seem prohibitively expensive.

So I've ordered a second hand wr125x caliper, which seems to be the only option left that I can think of.

More to come..

-- Edited by robs on Wednesday 8th of August 2018 08:45:02 PM

Dan-in-a-Van · Veteran Member

I had a quick look in the garage earlier. My caliper definitely has a similar spacer plate to yours. I've got to say my front brake works fine. It's got more feel and stopping power than the twin discs on my LC. :0

-- Edited by Dan-in-a-Van on Friday 10th of August 2018 07:17:59 PM

robs · Senior Member

Dan - that is really interesting. Do you know what mm thickness/diameter the disc is? Any idea where the original front wheel came from?

That caliper looks identical to the original TTR caliper, so I'm guessing that the disc thickness has to be less than 4.5mm in order for it to fit in the caliper and operate properly.

It'd be most interesting to know the disk diameter and the distance between two opposing bolt holes in the disk. If your bike has a thin but large disk (something I found difficult trying to locate) then it's possible people could use WR wheels with the same disc you've got, which would be another (simpler) option than what I'm doing - replacing the whole caliper/master cylinder.

If you don't have time to faff about taking measurements, could you take a pic of the whole front wheel, similar to this one? https://dust.cx/tmp/ttrf/caliper_bracket/IMG_20180723_130125.jpg - it might help answer some questions

-- Edited by robs on Friday 10th of August 2018 07:37:06 PM

Dan-in-a-Van · Veteran Member

I'll be back over the garage on Sunday. I'll measure the PCD and thickness, and see if I can find any markings to give me a clue what the front hub and disc are from.

robs · Senior Member

Great, thanks Dan!

Dan-in-a-Van · Veteran Member

My disc is approx 4mm thick. No idea what it came off originally. The size marking of the rim is below and a shot of the opposite side of the front wheel in case anyone can recognise the hub.

Here's the photo to match the view of your caliper you wanted. I un-bolted my adaptor from the forks so you can see a clearer view of it.

The mounting bolt of the disc PCD is 150mm

The disc measures about 270mm diameter (135x2)

robs · Senior Member

Hi Dan,

Thanks so much for those photos, it's starting to make more sense to me.

That is the same size disc as mine and the caliper looks the same as the wr125x one I bought. The only difference looks to be the YZ fork mounting points.

I've made another prototype adapter, this time for the wr125x wheel, disc, and with the wr125x caliper:

As you can see, there isn't much pad contact with the disc, I'd estimate it's about 33%.

I learnt quite a bit making this adapter though. The reason the caliper is angled at this angle on this bracket is because it was the optimal angle I could fit the caliper without the floating rotor mount bolts hitting the caliper on rotation.

Since I built this caliper I've learnt (if I understood correctly) that the caliper (which also floats on the caliper pins) should be mid-travel along the pins when correct axle spacers are used. I think this would give me the clearance I need to position the caliper properly on the disc.

No comment on whether I've test ridden this death trap.

New (safer) version coming soon..

-- Edited by robs on Wednesday 15th of August 2018 06:33:25 PM