916 Wheel Alignment

[squirrel_hunter]

Let me start by saying I'm not a Mechanical Engineer, I do however have access to a large sharp hammer. And you might be able to as well, check out your local Makerspace/ Hackspace. Anyway I'm fitting a Ducati 916 3 spoke wheel to my NT400 project bike. I tried first with a 848 hub but have came to the conclusion that its not possible, so I've gone for option 2 the 916 hub. A little checking on here and some measurements of my own I've made a sleeve and spacer to align the sprocket carrier (98mm ID 105mm OD for the main body but 115mm OD at the spacer. 80mm overall length 5mm spacer so 75mm at the main body giving a wall thickness of 3.5mm for the main part of the body, and finally a 2.5mm slit to allow for clamping. Your measurements may vary).

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So with that all in the swing arm I wanted to measure the wheel alignment to ensure the 916 wheel is centred. And I dont think it is.

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It was a fairly funky setup I used to get the measurement, a spirit level was the closest and longest flat edge I had laying around and making marks on some masking tape isn't ideal but it does give me something to work from. And I get a 3mm difference when comparing the centre line of the NT400 wheel with the 916 wheel. Now I do remember seeing reference to different wheel offsets and 3mm was a number that I think I remember so that adds up. However I cant find any reference with a solution.

So with 3mm being needed to move the 916 wheel away from the swing arm I can see two options, either a spacer between the axle and the wheel on the engagement spike side or a spacer between the axle and the hub. The spacer on the wheel side will be harder to make and might also require changing the spike bolt lengths as I would like to keep their length within the wheel the same. The spacer on the hub side will be easier to make but will move the bearing surfaces slightly though looking at the wear polish I dont think this will be a problem. I'll try and turn one up in the next couple of days to see what it looks like when fitted.

But I'm wondering if others can confirm my thinking and what solution is recommended?

[rpm10k]

IIRC my kit from WW for a duc wheel came with a 3mm thick spacer that went between the wheel and spindle, he may have a photo in one of the threads about the spindle mod if you search.

[riot]

Start here, with the OG mod:

https://www.hawkgtforum.com/forum/honda-hawk-gt-bros-discussions/mechanical-and-technical/12289-sneak-peek-ducati-wheel-on-stock-spindle

IIRC, you just need to move the drive pins and fit a spacer. You may need a custom wheel cone.

[squirrel_hunter]

From what I've seen in that thread in it being the WW mod its not the same setup as I've gone for. That one modifies the original spindle and then adds a spacer to it, I'm using a complete 916 hub, spindle, and wheel, so slightly different. Has anyone with a complete 916 setup found this issue?

I turned a 3mm spacer down earlier today for the hub side but only noticed when I got home that I didnt account for the radius at the end of the bearing running surface so its a little more than 3mm at the moment. I'll still stick it all together to see and then look to make another to allow for the radius, but I think I'll need to order a little more metal so probably need to design a caliper hanger and order the metal for that at the same time...

[squirrel_hunter]

So while I wait for the stock to create the spacer I thought I'd look at the caliper hanger. To get the hub and axle I bought a complete 916 swing arm and this also came with the caliper hanger for the 916, which was nice. So using that I made a few measurements and popped it into Fusion360, I had the hub and caliper mounting points at they are the same as thats not a point of modification, but hanger mounting pin to stop the rotation of the assembly was going to be different. I made an educated guess and turned to rapid prototyping to get what I wanted.



Using a laser cutter and some 3mm ply via 7 iterations I ended up with a caliper mount that would keep the caliper roughly horizontal against the arm in all degrees of rotation. There is a little nod but to account for that it would be an interesting ellipse that would then not be snug on the pin or I'd really have to design something well outside of my ability. So I'm happy with the key points being where they are.

I should note the Brembo P2 34 caliper I am using for mockup is from another project and is not the actual caliper to be used as it has a chuck taken out of it on the other side (thats how I got it). Additionally the pin is something I quickly turned down to centre it in the mounting hole as I have an M10 x1.0 die on order to create my own (I also need to design that for tightening purposes as well).



Now I'm happy with the relative positions of all the important parts but looking at what I have its a fair chuck of metal so I need to modify the design to add lightness and then somehow make one in ally, those curves are going to be interesting...

[6]

So while I wait for the stock to create the spacer I thought I'd look at the caliper hanger. To get the hub and axle I bought a complete 916 swing arm and this also came with the caliper hanger for the 916, which was nice. So using that I made a few measurements and popped it into Fusion360, I had the hub and caliper mounting points at they are the same as thats not a point of modification, but hanger mounting pin to stop the rotation of the assembly was going to be different. I made an educated guess and turned to rapid prototyping to get what I wanted.



Using a laser cutter and some 3mm ply via 7 iterations I ended up with a caliper mount that would keep the caliper roughly horizontal against the arm in all degrees of rotation. There is a little nod but to account for that it would be an interesting ellipse that would then not be snug on the pin or I'd really have to design something well outside of my ability. So I'm happy with the key points being where they are.

I should note the Brembo P2 34 caliper I am using for mockup is from another project and is not the actual caliper to be used as it has a chuck taken out of it on the other side (thats how I got it). Additionally the pin is something I quickly turned down to centre it in the mounting hole as I have an M10 x1.0 die on order to create my own (I also need to design that for tightening purposes as well).



Now I'm happy with the relative positions of all the important parts but looking at what I have its a fair chuck of metal so I need to modify the design to add lightness and then somehow make one in ally, those curves are going to be interesting...

Very cool. Cant quite comment on the work, or how to make that out of aluminum because its above my ability level. I would be doing it with a drill press, angle grinder and band saw.. (I'm sure you will do better than that) but i'm deff impressed. Great progress!

[eyhonda]

Nice work! I went down the same path a couple years back. You are on the right track.

https://www.hawkgtforum.com/forum/honda-hawk-gt-bros-discussions/mechanical-and-technical/member-build-threads/794777-eric-y-s-build-project-taka-92?p=794780#post794780

[squirrel_hunter]

Very cool. Cant quite comment on the work, or how to make that out of aluminum because its above my ability level. I would be doing it with a drill press, angle grinder and band saw.. (I'm sure you will do better than that) but i'm deff impressed. Great progress!

Thanks. Yep I have a plan on how to make it, basically a new machine turned up at the space, however it might not be big enough so will have to work around the constraints. Also as its a new machine I've go no idea how to use it so thats going to be interesting. I'll give it a go with a smaller part for another project first and take it from there. But for now I modified the design a bit with a couple of speed holes:

[squirrel_hunter]

Nice work! I went down the same path a couple years back. You are on the right track.

https://www.hawkgtforum.com/forum/honda-hawk-gt-bros-discussions/mechanical-and-technical/member-build-threads/794777-eric-y-s-build-project-taka-92?p=794780#post794780

Cheers, yes I've read that build thread, very useful and very nice work, great looking bike you've built there.

One question for you, did you use a chain roller? I've seen that come up a couple of times but I'm not totally sure on whats needed if at all.

[squirrel_hunter]

I've also reworked the spacer.



64mm OD, 42mm ID. As for the radius I used a bit of solder wire to get the shape with the intention of grinding a form tool out of some HSS, but then I remembered about a set of corner rounding end mills we had. And as if by luck a R3 matched perfectly. So I managed to mount that into a tool holder on the lathe and it worked perfectly.

I made it 3mm thick but also a 2.5mm one just to see. The 2.5 is closer based on my measurements which are not easy to get so there is a little error expected. But I'm going to get the micrometer on it to see what I actually have (I made a couple) and I think there might be a little additional offset from the wear in the original eccentric adjuster. So I'm still thinking 3mm is where I want to be and I might just have to take another stab at making the spacer, thankfully I bought a good amount of stock for this very reason...

[eyhonda]

Cheers, yes I've read that build thread, very useful and very nice work, great looking bike you've built there.

One question for you, did you use a chain roller? I've seen that come up a couple of times but I'm not totally sure on whats needed if at all.

Thanks! Yes, I have a chain roller on mine. It is used to keep the chain from rubbing on the lower part of the swingarm. The same function the factory slide does but most of these are now worn out with high mileage. frinesi2 makes one.

[frinesi2]

squirrel_hunter if you're interested I have one bracket kit left to do exactly the brake install that you're working on. I think it'll fit.

[frinesi2]

Also I think FFWD has a bunch of useful pics and dimensions and other general notes in his build thread. He and I went back and forth for a while working out which is which as far as donor parts, etc.

https://www.hawkgtforum.com/forum/ho...d-1#post832580

And for what it's worth, my duc swap is a turned-down eccentric, so it CAN be done. No idea on wall thickness, though. I bought it already modified and just slapped it on there.

There's some more discussion in my Suzondacati build thread.

[squirrel_hunter]

squirrel_hunter if you're interested I have one bracket kit left to do exactly the brake install that you're working on. I think it'll fit.

I might come back to you on that, going to give it a go with my design and the machine I have here first as it will be an interesting thing for me to try.

As for the 848 hub, yeah everything I read said it was possible but once I got one here to look at and worked some numbers the side wall thickness would be similar to tin foil. What I think has happened is Ducati changed the design or supplier at some point as I have seen the hubs with different part numbers on them. I posted it all up over here. But I'm in with the 916 hub now so just need to make that work...