Opinions on disc brake spoked rear wheel

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arcticXS

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All,
I have been researching alternative disc brake rear hubs for wire spoke wheels.

Finally, I found a "Talon" rear hub for a KTM MXer, which is narrow enough, and has a disc brake. This hub has bearings for a 20 mm axle (lucky!) and a width of approx. 150 mm. So plenty of space to fiddle around with spacers and caliper bracket.
It is light also, 1.5 kgs with bearings, meaning a wheel with aluminum rim and SS spokes will end up between 4.5 and 5.5 kgs. Disc, sprocket and caliper will all add to this, but a stock drum rear wheel is closer to 10 kgs...
This hub has no cush drive, but the stock drum brake hub hasn't either, so should be ok.
Talon says that they use 8 gauge spokes with this hub, so here comes my question:

Do you all beleive that a hub made for a 500 MXer, with 8 ga. spokes is strong enough for an XS?
Considering how an MXer is ridden, I tend to believe so myself, but I am interested in your opinions!
 
I haven't ordered a wheel yet, just figuring out all aspects of it before doing so. Sprocket size is one problem, as the sprocket bolt circle will not allow a smaller sprocket than 36-tooth.
I guess that would be OK with an 18-tooth countershaft sprocket. I use a 120/80-18 rear tyre, and crusing speeds here in Norway would be maximum 110 km/h. The general speed limit is 80 (90 on some roads)....
 
Hi all!
This has taken a bit longer than expected, but now I have ordered a wheel built to my spec from Central Wheel Components in the UK.
The hub will be a Talon TW632A, originally designed for a KTM500SX, the rim will be a Morad TR in 2.50x18, and stainless spokes will be used. I will need to make aluminum spacers for both sides of the hub, the RH side spacer will be an integrated part of the caliper bracket. I will use a Brembo 2-pot rear caliper from a Ducati, mounted below the disc. That way I can use the stock mounting point for the brake stay.
I did not order a brake disc with the hub, as the MX disc may be a bit too small for a heavy (ish..) road bike. Most likely I will order a custom disc from ISR in Sweden, with a diameter of 220-250 mm, depending on the clearance between caliper and spokes. As you may have guessed, I really like ISR's brake discs, I have one on the front of the XS, and also on the front of my Ducati. They have really good friction properties, and are lightweight also.

I also opted for the TR type (shoulderless) rim, and plan to get a similar rim on the front wheel later. Shouldered rims, like the stock XS rims look really nice, but just collect too much mud and water for my taste, and are harder to keep shiny.

I am at work on a ship right now, but when I get home,around the 12th of July, the wheel should be at my house. I will try to take a pic or two, and also weigh the wheel, to see how much weight it will save , compared to a stock wheel.

-Arcticxs
 
-2002 Sportster hub with stock bearings (3/4" ID)

-Sprocket from Rebel Gears (Google them) Custom cut and shipped for $70.76

-I can't remember which Harley model the axle was made for, but it was an odball model and took alot of trial and error before I got the right length. I bought it from Tucker Rocky (most local shops are Tucker Rocky dealers). But it's a "Biker's Choice" brand. I'll get the part number and price when I get back to work Monday. It was WAY cheaper than have a machine shop make me one. The axle is not too long. I just don't have all the hardware on the sides of the swingarm. It won't look like that as a finished product.

- To modify the Radian swingarm to fit the 3/4 axle is much easier than it looks. Pull the adjusters out of the swing arm. Stick them on a drill press and run them through slowly with a step-drill bit AKA uni-bit (like the ones pictured below). Make sure the bit's MAXIMUM diameter is 3/4". I bought mine at Harbor Freight. On the swing arm itself, where the axle goes through: use a straight edge an mark a line 1 mm above and parallel to the top of the slot, then do the same for the bottom of the slot. You're wanting to relieve each slot 1 mm on the top and 1 mm bottom so the axle will slide through. Carefully use a Dremel to do this after you make your marks. It doesn't have to be absolutely perfect because the adjusters will center the axle, but the more time you take the better it will look.


Step-drill bit:
214973565.jpg


The hub
rearhub.jpg
 
racerdave said:
Great setup Yardape and thanks for sharing. what are you gonna do for a brake disc and caliper?
Click to expand...

Brembo Caliper and this rotor to kind of match my sprocket:
http://www.ebay.com/itm/2000-2010-Harley-Sportster-NEW-SATIN-REAR-BRAKE-ROTOR-556-/120839344029?pt=Motorcycles_Parts_Accessories&hash=item1c22960f9d&vxp=mtr

fongbros said:
Not sure if you already know this or not, but Omars makes a conversion piece so you can use your xs disc front wheel on the back.
Click to expand...


The front hub out back is too narrow for my comfort. A guy I know did it on a wire wheel set-up and said the wheel flexed alot when he was cornering. It looks a little hood with all the adapter plates. Also for the price Omar's sells those things for, you can buy a "fo-real flattrack" Barnes-style knock off hub from A&A Racing.
 
arcticXS said:
Hi all!
This has taken a bit longer than expected, but now I have ordered a wheel built to my spec from Central Wheel Components in the UK.
The hub will be a Talon TW632A, originally designed for a KTM500SX, the rim will be a Morad TR in 2.50x18, and stainless spokes will be used. I will need to make aluminum spacers for both sides of the hub, the RH side spacer will be an integrated part of the caliper bracket. I will use a Brembo 2-pot rear caliper from a Ducati, mounted below the disc. That way I can use the stock mounting point for the brake stay.
I did not order a brake disc with the hub, as the MX disc may be a bit too small for a heavy (ish..) road bike. Most likely I will order a custom disc from ISR in Sweden, with a diameter of 220-250 mm, depending on the clearance between caliper and spokes. As you may have guessed, I really like ISR's brake discs, I have one on the front of the XS, and also on the front of my Ducati. They have really good friction properties, and are lightweight also.

I also opted for the TR type (shoulderless) rim, and plan to get a similar rim on the front wheel later. Shouldered rims, like the stock XS rims look really nice, but just collect too much mud and water for my taste, and are harder to keep shiny.

I am at work on a ship right now, but when I get home,around the 12th of July, the wheel should be at my house. I will try to take a pic or two, and also weigh the wheel, to see how much weight it will save , compared to a stock wheel.

-Arcticxs
Click to expand...

Did you post a picture of the finished wheel?
 

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