Skorpion on steel spokes

[tigcraft]

So everyone talks about swapping the heavy alloys for lighter rims which of coarse make perfect sense but what about a real traditional steel spoke cafe racer retro look? Has anyone done it as I fancy the look? I have a spare pair of mz125sm (lighter than standard incidentally)rims but the shafts are wrong so I want to borrow beg or steal some 17" baggys. Any viewpoints as brake calipers need to be different too? Eric

[edfmaniac]

I have mentioned the topic before with little response. I even contacted Talon hubs. They have the MZ and CCR bikes that use the same wheels listed on their site but they don't produce hubs for them, only a few other little parts. A friend just put motard wheels on his XR650R and I plan on borrowing his stock wheels to see how close they come to fitting the Skorpion. Any findings will be posted here but don't expect them any time soon.

[Bill Jurgenson]

there have been a few such rebuilds. I loolked for some photos but found nothing at the moment. I did find this of a modernized SRX

which would come very close.

I would not waste time trying to find wheels that might fit from other bikes, especially not from enduros. Rather find hubs first, used of new that fit the fork (rotor side and alignment) and swing arm. At the back there are many drum brake possiblities from newer japs with wire wheels. Before I would begin to change everything up front to accomodate an ill-fitting hub, I would make my own hub to fit as is; it is a very simple exersize at the lathe and drill press (or milling machine , better is available). Once you have reasonable, light hubs, lacing in decent rims is the smallest problem and definitely better than finished OEM wheels. In particular that lets you fit a narrower rim at the back for a 130 or 140 tire. All of the 17" enduro or supermoto wheels are much too wide. there is absolutely no reason not to use a drum at the rear.
If I were doing it, I would seriously consider fitting a drum brake in front as well. A good drum, well maintained ( and that is the crucial point) is at least as good as a disk. It's biggest problem is fading and that is not an issue on the street. That and maintenance; a drum need regular attention and the best in cables.
Maurizio has a some very nice ones:
http://www.motocicliveloci.it/italiano/catalogo/frenitamburo.htm
hubs for disk brakes as well (bottom of page):
http://www.motocicliveloci.it/italiano/catalogo/frenidisco.htm

Motocicliveloci has lots of goodies.
Two or three japanese OEM drums - a Honda duplex come to mind - would be fine as well.
As I said, if I were doping it.
I would not, however, because wire wheels are too heavy and need too much care for everyday use. They are not used on any street bike and that since decades for very good reasons, the least of which is cost. they are used off road becuase they are flexible and forgiving but this is not an argument for street use.

[samandkimberly]

Bill, I 100% agree that the best way to put a disc wheel on a modern bike is to fit/build the hub and work up from there, but have to disagree on several points regarding drums. Drums can be made to engage as easily as even the best disc wheels; I can make the 4LS brake on my TR500 road racer a one finger brake, and on that beast fading is no problem. But even the best brand new cables don't give you the feel of hydraulics, and more importantly, the combination of stiction and camming action of a drum makes it impossible to lightly decrease braking force when they are already applied - if you have too much brake you have to back off conpletely and reapply. This isn't much of a problem for even sprited street riding but is a major PITA when racing.
These two things can be mostly mitigated - I regularly ride a drum braked bike on the street and the brake is fine, but you just cant get a drum to perform nearly as well as discs on the race track. Then there's maintenance - drums take a world more, what with lubricating pivots, and multiple adjustments...and they *need* to be maintained in order to work well. That all said, I do agree they're fine for the rear where braking feel is not as important, and the consequences of forgotten maintenence not as dire.

As far as weight - spoke wheels, they can be made lighter than all but the lightest of cast wheels, particularly if you build your own. But they cant be made as stiff, and the lighter you make them, the more maintenance they need: thin spokes and alloy spoke nuts weigh practically nothing, but stretch.

I looked at putting spoke wheels on my skorp, and didn't find any bolt in solution, for what that's worth.

Sam

[Bill Jurgenson]

I have raced drums, Oldani and Fontana (real ones, not replicas) and am well aware of their ideosyncrasies.
A good drum is very much a 1-finger brake, much better than say any of the contemporary disk brakes, e.g. the Brembo 08s on the Laverdas (and Ducs and...) that repalced the the rather good Laverda drum. Those 08 calipers are two hand brakes (one fist is not enuf) along with a (beathtaking in the strictest sense of the word!) long stopping distance; I have had more scary moments with those than I care to think about.

the cable and its routing is all-important. And the angle of the arm(s) on the brake plate. the is important for control. And the maintenance, not just the greasing of the cams and oiling of the cables. We checked and if necessary refiled the shoes, checking with chalk, between each run. You have to if you want the drum to brake right.
Although the late double duplex monsters like that of the Yamaha 250 are real killers,

I prefer a good double simplex myself, much more controlable.
The Morini 3 1/2 brake is a really good example and one that with luck you might actually find.

or one from a Laverda.

Or lacking that, an Oldani

[radiograf]

Have a look at the following for pattern drum brakes: http://www.ajs-shop.co.uk/acatalog/copy_of_Grimeca.html

[Bill Jurgenson]

there are two of them but they are not very good. Of course, they only cost about 1/4 of the good ones.
Maurizio offerd them as well as better side plates to upgrade them:


The catalogue page now has "nondisponible" so I must assume that they are no longer available.

[DAVID THOMPSON]

all my drum brake use has been the units fitted to the bmw /2 1955 to 1969

i fussed with them for many years and found they worked good when you changed the shoe material
for a newer type
there big fault was the bike you were trying to stop was a bit over weight
and they need proper adjustment

and the big scare was stopping on an uphill grade
when you stopped you had to hold lever pressure firm if you let off any
they would unlock and not hold going backwards
and over the hill you went
i stopped the wife on a steep hill in Pennsylvania once when this got her by surprise
by placing my front tire against her rear fender.... and holding her till she could get sorted the problem
she was having with the shiftier on the gear box

rode a bike once the brake was similar to the BMW but had 4 shoes 2 on each side of wheel center
it was so good you could scare your self with it a stopie at 40kph with the rear wheel off the ground is not a good
feeling when your a careful rider
but if i custom build a bike i want that brake
dave

[tigcraft]

I did look at the link for grimeca drums which look impressive (thanks radiograf) and I see everyone's getting giddy over traditional drum brakes although it's discs I'm going to be using and in the real world im going to work on a budget as these bikes as rare as they are, are really only cheapies at the end of the day.
The thing is...... The current brakes I have are seriously good and out stop every Ducati I've ever owned so part of me doesn't want to let go of them but they just will not fit spoked wheels as they need to be offset pistons. So the debate continues............

[Phynoddery660]

Please forgive my ignorance here, but cast wheels were an option on the Mastiff and looking at the pictures they apear to be the same as the Skorpion Wheels, therefore must be possible to interchange?
CCM r30 also use the same Grimeca alloy wheels (fitted with 320mm discs) and also came available with spoked wheels the hubs being made by TALON.
Just my thoughts Allan.

[tigcraft]

I did buy some mz spoked wheels on the chance of them being mastif at staffordshire show recently and had same thoughts as you Allan although they were 125sm ones. But I think your thinking down the right channels to confirm my thoughts so I'll see what turns up. Eric