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Bike wheel convertion to split rim
Benzine - 1/2/12 at 10:29 PM

For my reverse trike I'm using some old honda comstar wheels. Originally I was going to take them apart and make a new center section that would mate up to my car hubs. Now that I've taken them apart I thought it would make more sense to make a whole new wheel center that could bolt on (like a split rim wheel). This would be better than a modified center as I could keep the width of the trike down by a few inches.













My questions are, how's the best way of doing this? Single circle of aluminium? If so what thickness? 12mm? Laser cut steel? thinner metal and re-enforcing? The original spokes are 3mm ally, 2 sets of 5 (second pillar drill pic shows 5 gone and 5 remaining)

SausageArm - 2/2/12 at 12:22 AM

Sorry i can't help you, i just posted this do i can keep an eye on how these wheels turn out! Best of luck!

v8kid - 2/2/12 at 08:43 AM

Can't you keep the old Comstar "spokes" and make up a smaller disc for the center? It would be lighter and cheaper. Plus thats the bit that takes most bending load so you know it wil be as strong as the original (if that is strong enough for your application).

Split rims use around 12mm thick castingsar the outer edge rising to 50 to 75mm thick in the center - but this has more to do with offset I think.

It may be easier to centralise a smaller disc than a larger disc - just 'cos its easier to work with and if you foul up there is not so much stuff wasted.

My split rims have steel inserts where the nuts locate and the alloy has to be thicker there. Bearing in mind your low weight it should be possible to replace the studs with 10.8 bolts and washers so you would not need the thickness and could use 12mm alloy. In this case you will need to centralise the wheel, not on the studs, but on the lip provided for just this purpose on the hub.

All in all I'd turn them up on a lathe rather than laser/water cut as I feel it would be more accurate at cetralising the boltholes to the center cutout. Just a feeling I guess there is at least one expert on here who can confirm or otherwise

Interesting

Cheers!

Benzine - 2/2/12 at 09:08 AM

Thanks for the info!

quote:
Originally posted by v8kid
Can't you keep the old Comstar "spokes" and make up a smaller disc for the center? It would be lighter and cheaper. Plus thats the bit that takes most bending load so you know it wil be as strong as the original (if that is strong enough for your application).


I could but it would be like the diagram I just made:



It's a bit exaggerated to show that the original center bulges out, and the disc brakes are too big to fit inside so they'd have to stick out (disc brake in grey) With a split rim they could sit inside the wheel and I could have longer wishbones/shorter vehicle width overall

[Edited on 2-2-2012 by Benzine]

Bluemoon - 2/2/12 at 10:36 AM

Humm. No real advice, but I would be worried about getting this correct, I guess the old motor cycle spider is not suitable as on a bike I guess all the force is along the spokes you don't really get any sideways forces (or you would fall off, though centripetal forces might cause some??)?? So I guess you can't use the original spider anyway on a car/trike??

[Edited on 2/2/12 by Bluemoon]

v8kid - 2/2/12 at 12:13 PM

quote:
Originally posted by Bluemoon
Humm. No real advice, but I would be worried about getting this correct, I guess the old motor cycle spider is not suitable as on a bike I guess all the force is along the spokes you don't really get any sideways forces (or you would fall off, though centripetal forces might cause some??)?? So I guess you can't use the original spider anyway on a car/trike??

[Edited on 2/2/12 by Bluemoon]


Good Point. It is a lightweight 3 wheelet I suppose but compared to the bike it's heavy and has axial forces.

How about conventional 13" split rims but using two outside sections? I think you can set down to 1.5" or so and they are available on 2nd hand market if you look for a while. You could then fit square edged 145 section tyres.

Don't think a disc of 12mm to fill the whole inside would be strong enough you would need reinforcing ribs of some sort and the cost would be far higher than second hand bits.

Cheers!

Benzine - 5/2/12 at 04:11 PM

quote:
Originally posted by v8kid
Don't think a disc of 12mm to fill the whole inside would be strong enough you would need reinforcing ribs of some sort and the cost would be far higher than second hand bits.


that wouldn't be difficult, I got the wheel for 99p

looks like i need to give this more thought/start again from scratch

v8kid - 5/2/12 at 04:19 PM

99p! You were done not worth a penny over 97p

Why can't I get these bargains?