Fitting brand X MC wheels to brand Y MC - Fabrication

Will Suzamahada YZF-GSX-RR wheel work on my Ducati? A short story on wheel modding.

I’ve seen this question posted on numerous motorcycle forums over the past decade. The answer is almost always yes… But the original question usually means, will the wheels be a direct swap? The answer to that one is almost always no.

My first motorcycle was a 1992 Suzuki Katana 750. I was in college and I was THE MAN ‘cause I had a crotch rocket (yes, young and dumb). It was the cats ***, the coolest thing since sliced bread etc. . The only problem (well, really one of many looking back) was the dinky rear rim (remember, young and dumb). The widest rear tire I could put on was a 150. It looked like a bicycle tire compared to a friend’s YZF 750 with the huge 180 on it. At a car show/ swap meet in Carlisle PA that summer I found a 199X GSX-R three spoke rear rim, 5.5 inches wide and would fit that beautiful 180 on it. I bought it for the princely sum of $75 (remember the college student part aka poor). I found a plugged take off at the local dealer for $25. I was $100 in and had the tire that would certainly get me more girls….
However the axle for the GSX-R was larger in diameter than the can ‘o tuna, and with the cush drive, the wheel was wider by quite a bit. This was back in the late ‘90s when eBay was still relatively small and finding parts wasn’t quite as easy as it is today. I managed to track down a used cush drive from a dealer in Arizona and sent a money order for $35 or so.

Back to the story… I found a local machine shop that would bore the swing-arm and chain adjusters to the proper diameter for the GSX-R axle (which I found at some other southwestern state and mail ordered). To solve the too narrow of a swing-arm gap problem, I put a hydraulic jack between the arms and bent the swing-arm open a few mm so the wheel fit. So at the end of this ordeal I had a katana with a 180 rear… but contrary to what I hoped, it did not rain women for me when I rode it around. I would up selling the bike the next summer and bought a 2000 GSX-R 750. The katana experience was my foray into swapping wheels.

While riding to work one day an inattentive driver made a left (coming from the opposite direction) right in front of me and I t-boned her on my pristine GSX-R 750. It happened about a mile away from the local Suzuki dealer. They came and picked the bike and me up and I bought a GSX-R 1000 on the spot. I have always had a certain lust for a set of Marchesini magnesium 5 spoke wheels. Now being a little older and wiser, and having the best Japanese superbike to date, I thought it was time to find a set of the Marchesinis. I located a 5 spoke cast 17’ front rim, but it was for a 1999 750. I got it cheap and lucked out that the bolt pattern was the same as the newer Suzukis, as was the axle diameter. The only problem was the earlier GSX-Rs had a wider hub.

By this point in time I had acquired a harbor freight mini lathe. I made a spacer to realign everything, and Bob’s your uncle, I now had a sweet Marchesini 5 spoke on the front. Some weeks later I had a wheelie go horribly wrong (not quite as young, but still dumb) and the Marchesini took the brunt of the damage. Poor wheel, I keep it hanging on the wall as a reminder of the squidly days.



A year or three later I got out of street riding and into trackdays. I converted the 1000 into a track bike and stumbled upon a set of forged marchesini 5 spokes in 16.5” diameter. They were set up for a quick change rear end and originally from a Canadian Suzuki superbike. I bought them, machined a cush drive and a few spacers, slapped on a set of slicks and bolted them onto the 1000. I can’t find a pic with the rims on the bike, but here’s one with the stock wheels.



It was a very fun bike, but way, way too much for me, and as I transitioned into racing, not a bike that was great to race on for a novice. The Suzuki sat in the corner while I raced a Honda F3. I picked up a 600RR and got to thinking about swapping the 16.5” onto it. I spent quite a while measuring and figuring and eventually the math revealed the rims would fit. New bearings and spacers on the front and the wheel went right on, but the rotors were 10mm too big. My racing team mate worked at a machine shop and machined the rotors down to fit. For the rear, I needed to make a few spacers, machine the rim on the rotor side and fab up a new rotor. The spacers were no problem on the HF mini lathe, but the rotor presented a challenge.
The mock up on the 600RR



We started with a piece of 4150.



Spent some time on the mill and came up with this:



Can anyone spot the design flaw?
Here’s the rear rim machined down a few mm so the brake will sit correctly:



The spacers, modded caliper bracket and and cush drive








And the wheels on the bike:




Unfortunately the bike in that configuration only lasted a few laps around BeaveRun before I totaled it. I keep those wheels mounted on the wall as a reminder.




I eventually rebuilt the RR, raced it for a few years, won a CCS Amateur championship and then sold it to buy a Duc.



I rode the 749S a few times and liked it a lot after it was fully set up but a too good to be true deal for a 749R fell into my lap, so out with the S and in with the R.

So now I have one of my dream bikes (the other is a Kawi KZ-900P done up in the CHiPs theme. I loved that show…) but I still lust after a set of 16.5” magnesium rims. They’re kinda like my unicorn (reference Gone in 60 Seconds remake). I search eBay every now and then for a set and recently stumbled upon a Marchesini front and Marvic rear 16.5 for cheap, but they’re intended for a 2002 Yamaha R1. My experience says they’ll fit with some work.

How to fit 2002 Yamaha R1 aftermarket wheels to a 749R.

I got very lucky with the front, the hub is narrow enough to fit without machining and the bearings are for a 25mm axle. After a lot of measuring and calculating, the front will need a 12.5mm spacer on the left side, and no spacer on the right side. That’s all there is to it. Here’s the spacer being machined out of titanium:










Now with the wheel centered we can check how large of a rotor will work (with the small wheel diameter a 320mm rotor will not allow the clearance necessary to remove and reinstall the calipers). The 2002 R1 rotors are 298mm as opposed to the 320 for the 749R. New R1s have a 310mm rotor. I can remove the radial spacers and get pretty close for it to work with the 298s, or make smaller spacers to go to 310. The R1 rotors will need to be spaced out 2mm each from the hub plates.

I made a few different size wood templates to check clearances. 320 is too large, 310 and 298 will fit. The benefit of the 298 is I don’t have to make new hub plates, but without machining the calipers a little there will be a portion of the pad outside the rotor diameter. I think I’ll try the 298s and later make new hub plates to work with the 310mm rotors. This pic shows the templates, one with a hub plate in the middle.


Here are the templates bolted up to the bike:



So back to eBay for some rotors, ronayers for the bolts and I’ll be set with the front.

On to the rear.
I have a bunch of measurements so far on the rear, but I still need more and need some higher tech stuff that what’s currently at my house. I did get the rear 749R rotor on a CMM to layout the hub diameter and bolt pattern. The rear Marvic wheel will need a new hub plate for the rotor. I’m hoping the cushdrive will work. I’ll know next week when I get the rest of the measuring finished.

Here’s the rotor on the CMM. Please excuse the poor quality; I took this with a phone camera.







Continued

Part 2

I measured the stock forged aluminum rear wheel and the Marvic magnesium wheel to see what needed to be changed. Sorry, no photos of the set up this time, but picture this micro hite:


on a 4’ by 8’ granite surface plate.

Good news. The rear will work. I will need to make a new hub plate to align the rotor. I’ll be using a stock Ducati rear rotor which is 240mm vs. the R1 which is 220. The Ducati rotor has a 5 bolt pattern, so regardless of the alignment issue I knew a new hub plate was necessary.

The Marvic cush-drive will need to be shaved 4.3 mm back on the sprocket mounting face to align the front and rear sprockets. I’ll need to press out the sprocket mounting studs, then put them back after machining. Hopefully the studs can be reused, but I have a line on a set of replacements if not.

The cush-drive will need new inner and outer spacers and a new bearing. Marvic made the cush-drive with a captive spacer, I will duplicate this with the new bearing. With the stock Ducati method there is a possibility that the drive side spacer gets cockeyed or falls out, but the captive spacer prevents that from happening. The wheel needs two new bearings and a new inner spacer and finally a new out spacer for the rotor side. The stock caliper bracket does not need any modification.

The most complex part will be the rotor hub plate, I’ll get as many photos as I can of the process from raw stock to finished part. I am searching for a block of magnesium. If I can’t find it, I’ll use 6061 which is plenty strong, but also 50% more weight all else equal.

So on paper, with slight (or maybe moderate) modification, Yamaha R1 wheels will work on a 749. The proof of the pudding will be in the taste…

To make up for lack of photos, here’s a shot of the bike on the MotoMFG stand with a black 749S cast rear. My forged wheels are white and I like the color quite a bit, the black is growing on me.







Let’s go to the front wheel first. Last we left off, the bearings and spacers were all finished and the wheel centered perfectly between the forks. The only remaining issue was rotors. The R1 rotors are 298mm diameter, the Ducatis are 320. The Ducati rotors are also 4mm farther apart than the R1. By machining the calipers where they sit on the fork legs I can accommodate the smaller rotor. To space the R1 rotors to the correct distance while utilizing the Marchesini hub plates, there are two options. Space the rotors out, or space the plates out. By spacing the plates out, the extra mass of the spacers is closer to the hub having a smaller effect on the wheel inertia. To do this two 2mm thick 64mm ID and 100mm OD spacers are needed. I used 6061 for this for the sole reason that I had a piece of stock in 4” diameter sitting next to the lathe. I forgot to take in process pics, but here is a photo of the finished parts.



This is how they fit on the wheel to space the rotor hub plates out 2mm.



I still need to drill the 6 thru-holes on each piece.


On to the rear. The sprocket on the Marvis cush-drive needs to move closer to the wheel 4.3mm. I chucked the drive after pressing out the drive studs and took off the necessary material. For what it’s worth, magnesium is really awesome to machine, like a hot knife through butter. Here are a few photos of the process.
The drive indicated in and ready for cutting:



And an in-process cut:




I need to press the drive pins back and new nearing back in and the drive is finished.

Finally, the last major piece is the hub plate to carry the rear rotor. The Marvic piece for the Yammi rotor is a 6 bolt pattern and the R1 rotor is 220mm diameter, while the Duc is 240mm diameter and 5 bolt. The rotor also needs to move 27.4mm away from the Marvic hub. I designed a part that should accomplish this:



I started with a 6.5” diameter piece of 7075 aluminum. The aluminum is approximately 50% heavier that magnesium, but it’s also stronger so I’m not worried about it holding up to race bike abuse – also I rarely use the rear for any heavy braking.

Here’s the large chunk indicated in and a clean up pass on the end and OD:



Be careful about how long the chips get, it’s no fun when they wind around the part and start whipping around.



Here’s the OD and rotor lip finished:



And test fitting the Ducati rotor:



And what the pile of chips looks like so far on this piece




Continued

I left off with the rotor adapter bores and locating flange finished. The next step was to part the adapter from the bar. My el cheapo band saw didn’t have the balls to cut it, so I enlisted some outside help for that.

Next, turn the back side of the adapter to get the critical thickness, which sets the rotor at the correct distance to center in the caliper.

The next step is to machine the 6 bolt holes and counter sinks for the adapter to wheel hub mounting and drill and tap the 5 holes to mount the rotor to the adapter. Here are a few shots of the set up and drilling of the 6 smaller holes. The critical part of this setup was to determine the center of the bore; all the bolt holes are referenced from this point. A little off and the bolt holes will not line up on the wheel. Fortunately I got the alignment correct and both the rotor and adapter are concentric on the wheel.




With the completion of the rotor adapter, the remaining pieces for the rear wheel are the inner and outer cush spacers, inner wheel spacer and rotor side spacer. I didn’t get any in process pics of these parts, they were all turned from aluminum and relatively simple. I made the inner and outer cush spacers captive so there is no risk of them falling out or becoming misaligned when trying to install the rear axle. Once I test fit everything I realized the sprocket bolts are too long. I threaded a nut on each one and parted off 5mm which gives plenty of clearance.




Here’s a shot of the trial fit of the rim on the bike, and another of the final fit with a tire on the rim. Everything lines up perfectly. The rear is a 195, I have a 205 around somewhere to check clearances with but based on the fit of the 195 it should also work well.






The rotor spacers are the last component for the front wheel. Each disk will need 6 holes so the mounting bolts can pass through. The disk is only 2mm thick and I couldn’t come up with a great way to hold it down on the mill without causing distortion. The method I used to layout and drill the holes was to put the spacers on the rim and the rotor plates over it. I made up a drilling guide to center in the rotor plate and allow a small pilot drill to pass through and drill the spacers. I made one hole to size from the pilot hole, then bolted everything to the wheel and finished the pilots for the remaining 5 holes. Here’s a shot of 5 holes drilled to size and the 6th with a pilot hole. Repeat for the other side and the front wheel is finished and ready to mount up.




So start to finish it took about 15-20 hours of work which includes the measuring, calculation, machining, and test fitting. That’s basically what is involved in fitting Brand X wheel to a brand Y bike. If anyone has any questions I’d be happy to try to answer them. If there’s any interest I can post up some photos of my garage where the majority of the work took place.


Ryan

Very cool.

Very nice machine work. Please post
up pics of your shop.

jhn9840
John

Nice work on the machining. You mentioned early in your posts that you got a HF mini-lathe. What lathe were you using when machining the titanium wheel spacer for the R1 rim? The finish on it looks really nice.

Also, I knew this looked familiar. I remember reading it on the Ducati.ms forum previously.

Anything cab be made to fit vanything,just depends on fab skills or check writing skills!

I give up - what was the design flaw? I've been in the middle of a similar wheel swap for what feels like forever and at some point I'll have to make a new rotor.

What was the material you used?

jhn9840 said:

Very nice machine work. Please post
up pics of your shop.

jhn9840
John

Click to expand...

I'll get some photos this weekend if I can get the place cleaned up.

Ryan

You got skills Ryan, Very nice work.