Brakes Dual disc brake hubs and forks

[Frankenstein]

Well, it's on there but I'll probably be doing it again because there is actually some flex in the 3mm thick steel plate. I will have to drill new IS mount holes and use the appropriate IS-PM 203 Shimano adapter, instead of this concoction of homemade IS+43 plate and IS-PM 160 adapter.
I also found (even without braking force applied) that the 3mm plate brings the caliper slightly too close to the spokes and there isn't enough outward adjustment in the PM slots to centre the caliper over the rotor, so I did a lot of grinding and filing to get it "perfectly" lined up.

Do NOT use Stupid Shimano XT precision engineered bloody racing brakes haha, there's no clearance for doing the build by hand. Be sensible and use Hope C2 #3 if you're going to mess around with a homemade adapter plate.
(Hope C2 #4 I think is the one that actually mounts direct but that limits you to I think a 165mm rotor.)

I'm Definitely leaving the right hand side for someone else.
Anyway here are the pictures of my LEFT side +43 mount for the dual disc mount Marzocchi Z1 1997 that I already know isn't the final version.

View attachment 75908
View attachment 75909
Sorry the photos are sideways and I have no idea why.

How about a piece of angle steel, a small one with areas cut out to fit flush with the caliper and fork mounts, drop the caliper bracket. Then the 2 holes that mount the caliper to the bracket can be made just a hair over sized to help you get the right movement for alignment.

Can even bring the caliper closer to the fork.

 

[FurryOnTheInside]

How about a piece of angle steel, a small one with areas cut out to fit flush with the caliper and fork mounts, drop the caliper bracket. Then the 2 holes that mount the caliper to the bracket can be made just a hair over sized to help you get the right movement for alignment.

Can even bring the caliper closer to the fork.

Yes and no, I think. It would allow the caliper to be mounted further out from the spokes which would be cool, and there'd be two less bolts in the whole construction so that's a good thing too.
But the angle iron I could get wouldn't be good at all, and using steel over an even longer span it would flex more under heavy braking. There's actually very little flex in the chunky aluminium adapters.
I think it would be great to get a second layer of plate over the outside of the fork's FS mounts and have spacers on the IS bolts.
But #2 whenever I get around to it will just be shortening the steel plate, I think, and using a longer aluminium adapter instead. It's what I should have been making the first time before I got distracted by the dimensions of the old brake plate I was using to make it from.

Here are a couple of pictures of other people's much better, aluminium, Formula Standard to International Standard mounts.


And at least the last one is steel and apparently two layers(?). Not sure about the first of these two

 

[orangeburger]

The simplest answer to double front discs is to buy 2 hubs with disc mounting, cut them in half and weld them back together again.