Mag and spoke drum interchangeable?

[holeinthehead]

Hey all,
Mid-way through getting my Christmas present back on the road and I'm planning ahead for a spoke order to rebuild the crusty wheels. I may have a lead on a drum brake mag rear wheel (not sure if there was ever a rear disc brake) and may get it on in the interim - the front wheel isn't too far gone and can get by with a little scouring.

The wheel in question is a Grimeca 18" and I thought it might just take the drive and brake without any fuss. Anyone know better?
Thanks in advance.

[72degrees]

There were two rear hub/brake sizes on the spoked wheel 350 machines and two versions of sprocket carrier (5 bolt and 6 bolt). If yours is 5 bolt then a cast wheel uses the same brake shoes, spindle and cush drive rubber so I'm guessing it should fit though I've never done it. Someone who knows for sure will be along in a moment. By the way, make sure it is a 350 wheel. The 250 twin uses only a 1.85 rim rear cast wheel and a 5 bolt sprocket carrier.

[MickeyMoto]

Later bikes disc rear.

[Ming]

T...The 250 twin uses only a 1.85 rim rear cast wheel and a 5 bolt sprocket carrier.

... unless you have one with a 1.85 rim and a 6 bolt carrier...

[huub]

depends on what spoked rear wheel you have.
the 180 mm sport drum sprocket carrier fits the cast wheel, , the 160 mm strada drum sprocket carrier doesn't.

[72degrees]

T...The 250 twin uses only a 1.85 rim rear cast wheel and a 5 bolt sprocket carrier.

... unless you have one with a 1.85 rim and a 6 bolt carrier...

D'oh - quite correct! 6 bolt on the 250 and the early Strada drum sprocket carrier

[72degrees]

depends on what spoked rear wheel you have.
the 180 mm sport drum sprocket carrier fits the cast wheel, , the 160 mm strada drum sprocket carrier doesn't.

That makes sense. The 160mm Strada sprocket carrier is 6 bolt not 5.

[holeinthehead]

Thanks all, I thought it might be a specific fit. My spoked rear is a 6 bolt sprocket - I'll measure the drum tomorrow. The cast wheel I'm looking at is a E-1.85x18" DOT-D if that means anything.

[72degrees]

Thanks all, I thought it might be a specific fit. My spoked rear is a 6 bolt sprocket - I'll measure the drum tomorrow. The cast wheel I'm looking at is a E-1.85x18" DOT-D if that means anything.

That sounds like it could be a 250 cast wheel, which would be confirmed by it having 6 'vanes' on the driven side and 160mm brake, so in theory it would fit a 6 bolt spoked wheel sprocket carrier, but would be restricted on the tyre width you could fit. However, the 250 uses a completely different rear wheel spindle and the part number for the brake plate is different (though the shoes are the same) to the 350 160mm version - so there may be issues when you came to put it in.

Having said that, I did once put a complete 180mm Sport spoked rear wheel and carrier in to a 250 swing arm (for the Rotax-Morini) - but it required a bit of ingenuity by modifying the nut for the 'dummy spindle'.

[holeinthehead]

WELL - as luck would have it, I came across a 36 spoke Borrani rim at a swap meet yesterday or $20. So that takes out the refurb on the old rim out of the equation - I can just make the swap and maybe I'll come across it's narrower counterpart one of these weekends.
Will still do some measuring, it'd be good to know I can make a change if I need to.
Thanks all

[72degrees]

WELL - as luck would have it, I came across a 36 spoke Borrani rim at a swap meet yesterday or $20. So that takes out the refurb on the old rim out of the equation - I can just make the swap and maybe I'll come across it's narrower counterpart one of these weekends.
Will still do some measuring, it'd be good to know I can make a change if I need to.
Thanks all

Which reminds me that I have an old, but sound, Akront non-valanced 2.15 x 18 36 spoke holes, drilled for a Morini, alloy rim in the shed if anyone can make use of it. Can't remember for sure but probably off a 180mm rear hub wheel I had on the Rotarini racer.