Search results

D8ve - a straight swingarm would be much easier the build - although it would still have to splay from the narrow pivot and out around the wheel.

OK - I get it now. Thanks everybody... back to the drawingboard.

But aren't the hub and the wheel all of a single piece? The centre point of the torque is where the axle tries to spin in correspondence with the rest of the moving wheel (in a clockwise direction according to my diagram), but is prevented from doing so by it being fixed to the static dropout...

This is what I struggle to understand, d8veh. I can see that if torque was caused by the backward movement of the bike (if the motor was in reverse), the rod would be forced to compress (and thereby bend or bow). But it seems to me, with the forward movement of the bike the anchored rod would be...

Slimjim. The dropouts are exactly as shown in the photo I pasted up a page or so back (in fact that's my frame). The width of each dropout is 8.3mm. From my understanding, the forward motion of the wheel will place a downward force on the swingarm - as shown in my diagram below. The area shaded...

I don't disagree with you, d8veh (and I certainly respect your opinion). It's just that I like setting myself design challenges and thinking through ways to make them succeed (elegantly, if possible). The good news is the Xiongda website is back online :-)

Yup, I haven't got any of the crank/chain mechanisms attached yet, so I'm not sure if a rod would get in the way of this. I could just fit it to one arm (the non-chain arm), but that might not be effective. EDIT: The function of the rod would only be to take away (or reduce) downward, vertical...

Thanks for your considered response Slimjim. You raise some valuable points. To eliminate any 'counter tension' a taught cable might cause to the swingarm, maybe a 2mm steel rod (think coat-hanger wire) would work better instead. This could be attached in either of the ways shown in my image...

Yes I will be very careful - and I may well sort out an alu arm once I've completed this conversion to a working bike. I understand the issue here and I think a possible solution might be to run a tight 1mm steel cable from the back wheel axle down to the axle for the swingarm... this would...

I have the frame now- looks in great condition... barely used, if at all :) I've decided to keep and use the carbon swingarm for the time being - as rebuilding the item in alu will be time-consuming and tricky - with its various angles. I'm not intending to use the bike off-road at the moment so...

Well, a friend has a TIG but to be sure, I might ask in the local cycle shop if they can weld alu. If I go with rectangular box tube, I can ask the supplier to cut pieces to the dimensions I supply - or cut them here on my mitre saw. As for the initial design, I'm pretty good with Fusion 360...

chris_n... that sounds like a good solution, but I think it'd be beyond my abilities - would like to keep the welding I'll have to do to a minimum.

So far it's shaping up to be very cost effective. And - from a design point of view - I like the look of the bike... it's one of a few from that era that lends itself to conversion (CF swingarm notwithstanding).

trex - is there anything I could do to prevent this happening? Such as raising the height of the shock mount to its original position and welding the two arms together with a hefty central 'shoulder'?

A straight swing arm in the rectangular tube would be the easier option (and the preferred one in terms of my metalworking abilities). Although I'm not sure if a straight tube would clear the crank/BB.

Here's a technical drawing I found of the K2 (which has been very useful for planning out) and I'd like to shape the swing arm as closely as I can to its original shape. That's not gonna be entirely possible with rectangular tubes - and I suppose I could build the arm as a frame of round tubes...

Top drive - yes, I can see the point you're making. Even though the rear axle will essentially be a single gear, its arc (from the chain crank) will still diverge from the arc of the swing arm as suspension is brought into play. It therefore seems likely I will require some form of chain...

Thanks guys. I've been looking at some alu rectangular tube - 6063T6. I'm thinking maybe 80mm x 20mm with a 2mm wall. I'll weld some horizontal dropouts onto these (for wheel adjustment to take up chain slack) and work out what's needed for torque and disc brakes (I've heard there is a...

Again, great advice, thanks. I would, of course, reinforce both arms, equally, to balance things up. Another thought I've had is to get the swingarm remade in alu... maybe CNCed from (say) flat 12mm plate to the contours of the existing item and then welded. The frame is currently on the way to...

Thanks, Slimjim - very useful advice. I was actually thinking of wetting on a couple more layers of CF to the swingarm to give it more strength. If this is possible, I could - at the same time - bond on an alu plate for the torque arm... as well as add whatever is required to fit a disc brake...