What spoked disc/hub to use?

[nvr2late]

Not having any luck finding a suitable disc hub for a spoked rear wheel, i've seen the Omar's conversion, but would like something different.
Not much choice of anything over here in the U.K, been looking for a Yamaha XTZ 660, or 750 hub (Big trailbikes), but more chance of buying a Unicorn's horn i think, (and No, i don't want a Unicorn's horn thanks!)

 

[5twins]

I've heard some of the late '70s/ early '80s Kawasaki and Honda street bikes had these. Can't give you a specific model but it might be worth some research.

 

[XS1961]

Try a DT400/250MX . Honda CB550/750.

 

[gggGary]

The older KTM hubs/rotors/calipers can be made to work but the smallest available sprocket AFAIK is a 38 tooth. The axle is the same diameter as the XS650 axle.
Here's a pic of one with a 17" x 4.5" supermoto rim on it.

 

[XS1961]

A change of subject - just look at that exhaust..Drool, where can I get one ?

 

[gggGary]

A change of subject - just look at that exhaust..Drool, where can I get one ?

No no, no no,you can't have that no mo. Seriously the guy that one offed it ground off his usual ID mark and swore the owner to secrecy.
You could show the pic to gordanscott see if he's dumb enough to attempt it??? The can is a duck aftermarket piece $$$$$

The pipe is plain steel with multiple oil wipes when it's hot as can be.

 

[osteoderm]

This is a perennially interesting topic, and one that I've been hammering away at myself. I started with stock XS front hub/Omars conversion, and am now too deep into widening/modifying another XS front hub (thanks again gggGary!) into a bitsa frankenhub...

After much research, I'd suggest asking the question, "what would be the problem with XX hub?" rather than "what hub would fit out-of-the-box?".

Pretty much any alternative hub will require custom bearing spacers, so you might as well resign yourself to this from the start (not really such a big deal; often easier to make than to find). Next, look at bearing sizes; IMHO, sticking with the stock XS axle saves much frustration, so find a hub that will fit or adapt to some bearing that will fit the XS axle.
Bearings suitable for stock 20mm axle are easily found in 47mm x 14mm and 52mm x 15mm sizes. It follows that alternate hubs that will fit these bearings are advantageous.
Next, the brake. It's great if you can find a hub/rotor combo that works; after that, you need to mount a suitable caliper to fit. Once you just give in and commit to building a caliper hanger to suit your application, many other annoying issues disappear.
The sprocket issue seems the most annoying, but in reality is simpler than it seems. The XS uses such a small sprocket (compared to many other applications), that it may be hard/impossible to find a stock-application sprocket to fit whatever alternative hub you've chosen. However, I've found that custom sprockets from reputable manufacturers (Rebel Gears comes to mind) don't actually cost more than any other quality sprocket.

To sum up: pick any arbitrary rear disc-brake hub, then take a look to see if it will take a 47mm or 52mmOD bearing. If it's a stock-application spoke wheel/disc brake, then there will almost certainly be a matching stock-application brake caliper available. Measure the sprocket BCD, then order up a 32t-36t 520 sprocket to suit from Rebel Gears. The caliper hanger will need to be carefully made, but will be fundamentally no more complicated than any of the usual front-brake Brembo caliper adapter plates.

The hardest part is just making up your mind and accepting that you'll have to dive into some fabrication; once you commit yourself to making a handful of custom parts (rather than struggling to find/adapt bolt-on solutions), you may well find that things go more smoothly than you thought they would.

 

[gggGary]

Osteo gives good advice. One sticking point is that the diameter of the hub's sprocket bolt circle often dictates the lower limit of sprocket tooth count. That's the limiting factor on the KTM hubs for example. I found a 36 tooth KTM sprocket on eBay but I think it's a physical impossibility unless the bolts are outside the chain You may also have to have an offset front sprocket made to line up with the rear. The XS chain center line is kinda narrow.

 

[gggGary]

BIG detail pic of the bike above.

Before someone asks; stock shocks off a CB1

 

[nvr2late]

Try a DT400/250MX . Honda CB550/750.

Thanks for that, but those are hub braked models.

 

[pekka]

Pre 1998 Yamaha YZ Hub is a close fit. Smallest sprocket is 40 teeth. Will need custom brake disk. Stock axle spacers work but will need an additional spacer on the sprocket side. This is what I'm going to use. Should be done in couple of months.

Also, a Yamaha TTR250 hub could also work. Fits with stock spacers but the sprocket to disk spacing is about 5mm wider than in the YZ hub.

Pekka

 

[XS1961]

Thanks for that, but those are hub braked models.

oops..Missed that bit ..
Im not into rear disc brakes, prefer drums so must have unconsciously skipped that

 

[racerdave]

Honda's early {before 78, 75-76 maybe 77?} SOHC 750 SuperSport had a rear disc with wire wheels. Kawasaki's KZ750 twin had a rear disc with wire wheels

 

[racerdave]

The older KTM hubs/rotors/calipers can be made to work but the smallest available sprocket AFAIK is a 38 tooth. The axle is the same diameter as the XS650 axle.
Here's a pic of one with a 17" x 4.5" supermoto rim on it.

gary, is this in your stable?

 

[kestrel]

The RD250 C models had a spoked rear wheel with disc brake, I've just scored a complete rear wheel off the bay but they are as rare as hens teeth! The spindle size is 17mm, this is not an issue as I'm doing a monoshock conversion using a GPZ550 swingarm which has 17mm axle slots.
My first post by the way......

Dave
Isle of Man

 

[kopcicle]

time for a little necro posting

I was asked elsewhere so ...

The rear caliper is bone stock 2F0 . I was careful to leave as much of the conversion stock as possible . With the un-modified KZ750B LTD M1 twin 18" disc brake hub and rim the Honda disc centers in the caliper once .200" is taken off the diameter . Now one caution , the disc was "marked" CB200C but I did not take it off myself so I won't swear to it . I'm told that the KZ305 is very similar also so ya pays yer money and takes yer chances . I did turn down one side of the rear hub and I believe it was the sprocket side . I'll know more in a week or so . As the project stands the disc is centered in the caliper and the sprockets are so nearly in alignment that I may be able to let it go . I did have to futz with spacers for hours but it fits . I should say almost fits . I'll have to pull the wheel toward the drive side about .250" to put it on center line but with all else falling into place I'm far beyond complaining. I had considered the modification of the front hub to carry sprocket and disc but going without the dampener was more than I or the gearbox and transmission could tolerate .

~kop

 

[gggGary]

GS750 1000 spoke rear wheels are a fairly easy conversion and lighter than the Kwak.
The only thing I don't like is the spoke flanges on the hub are kind of close together I would guess this will allow a more flexy wheel....
The stock rim is 2.15-18 alloy





Sprocket bolt circle is different and the Zookies used 630 chain but custom sprockets aren't that bad

 

[kopcicle]

Lighter ? Possibly but I don't know by how much . If you don't have both I guess I'll have to weigh my junk . I'm lucky I have one of the best in my neighborhood thewheelmaster.com so I didn't have to worry about lacing the 2.50 Borrani to the hub . It was a little tricky as the holes didn't perfectly line up and had to be reamed slightly . The "Kwack" is also a 2.15x18"
I planned on putting some serious torque to a significantly larger contact patch so Morrie and Jim didn't waste any time on small spokes . Even the harder compound K180 Dunlop is much softer than most street compounds so grip isn't an issue . The swing arm may be a question mark though .

1976 KZ750-B1
1977 KZ750-B2
1978 KZ750-B3
1979 KZ750-B4

The aluminum H-D rims are all made by Borrani and first appeared in 1960. There are several different types, '60-'63 front in 18 or 19, '64-'69 front in 18 or 19, '60 -'69 rear in 18. Any of these interchange with the steel rims for the same type brake. The '60 and '64 types do not interchange with each other, the spoke drilling is different. In '70 the rims changed to a deep drop center type, much stronger but heavier. The spokes on the deep ones are shorter so a pre'70 rear and '70 up rear do not interchange unless spokes are also changed. The front also changed again with the arrival of the disc brakes. Once again they do not interchange with the drum brake type and no rim was made for the '73 style hub, only the '74 and later. All the original equipment rims have the part number stamped in them near the valve stem hole. There are no markings on the outside like normal Borrani rims. There are also several variations that are race bike models (different numbers) and even a few for the US made lightweights (identifiable by having only 36 spokes)! Normal tires fit them all.

There is one other difference between the pre '70 rims and the '70 and newer aluminum rims and that's the bead seat profile. The earlier ones are all WM profile. The '70's ones are CM profile.

The CM profile rims are made for use with Goodyear Taper Bead Base tires. I think it was an attempt on the part of Harley and Goodyear to corner a part of the motorcycle tire market.

It doesn't mean you can't use them. I have an 18" steel CM profile rim on the back of my '96 Sportster, with a Continental SuperTwin 120/90-18 tire. And am about to lace up a 19" disc brake front aluminum rim to a mid star hub to use on the back of my Pan project with a 4.00 x 19 Sears copy of a Pirelli MT53.

The rear Sportster 18" rims as well as both styles of the front 19" rims are 2.50 at the bead seat, so the width is OK to use a front on the rear. You want to use the one for the disc brake though, because it's drilled for a smaller diameter hub. The 18" will be part number 43008-70, and the 19" will be part number 42998-74.

Here's a link to a tech piece that has more details.

http://www.jockeyjournal.com/forum/showthread.php?t=22085

Thanks to RubOne and M.O.ther from the "JJ" for hitting on all the weird about the Borrani hoops .

I have had the "Kwack" hub resting inside D.I.D. , Akront , Takasago , and recent copies of the classic valanced/shouldered rim and whether originally drilled for drum or disc , front or rear , they are all off by a little bit but usable .

any questions ?

~kop

 

[gggGary]

I have both zookie and kwak set ups (naturally) I think I have a 305 front rotor on the KZ750 hub. I'll do a weigh up.........
Some e-bay vendor from spain was advertising a wide 2.75? 18 "Akront" but it looked REALLY crude, enough to scare (even) me...
I would like a nice 2.50 to 3.00" alloy 18" preferably shouldered and with a bead hump. A guy ebayed a wide rim on the suzuki hub a while back but it was 17" and rather TOO wide for my taste. A Radian arm is nice upgrade, even the TX750 arm is better than the 650 arm but that brace kit sold by Joe??? out your way looks very trick.
This arm was fabbed by a one man shop down south somewhere.

 

[XSLeo]

I often think about this very thing. Couldn't someone with a bit of skill take a mag disc wheel, cut out the hub, Then turn down the area just inside the disc rotor and sprocket so that you could mount a flange that could be drilled for spokes. This way you could turn mag hubs into spoke hubs.
If this could be done You could drill 36 holes in these flanges for using stock 18 inch rims or drill it for any number of spokes so you can use any rim.
If this could be done then the hub would definitely use bearings and axle's as well as spacers that fit our swing arms. No problem with sprockets or rotors. Anything that would fit a stock wheel would fit this hub.
It might be easier to get a new hub built to use as such. This might prove better if it could be built to use a cush drive.
Leo