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Discussion Starter · #1 ·
These wheels are off an early 2000's Derbi GPR 50 wheels, rotors tires. My plan was to use them for a mini-gp conversion.

These are 16” wheels. As you can see in the pictures I bought them for a conversion project on a CR85. They fit pretty decent right out of the box, but it was going to take custom spacers to get them on. The bearings in the wheels are the same as the rear axle of the CR85. The 16” size let the rear wheel fit with a little bit of clearance to allow chain adjustment.

I recently acquired a bike all set up for mini, so this project is up for sale. The CR85 in the pictures is also for sale.

The wheels are dead straight and in great condition…there are a couple marks from tire changes but otherwise the rims are mint. The rotors are also flat and smooth with little wear. The front rotor is 260mm. The rear rotor is 220mm. The sprocket is a 420 size chain, 42 teeth. I have identified the mounting pattern with AFAM, and other sizes are available as well as offsets to help with your application.

The tires are practically new Michelin A39/M39…still have the nipples on them. Sizes are 90/90/16 front and 120/80/16 rear. Before I bought these I found that much of the good rubber available in 12’s is available as 16’s. The size of the front rotor and being tubeless was a bonus for what the set cost me. I am half tempted to keep them for a future project cause they are so neat.

I’ll ship them anywhere in the 48 states for $350 just as you see them. Trust that I will pack them carefully to ensure they are still round when you get them. Pick up for $300, located in Greenville, WI. I will likely be able to overlap at Road America or Shawano/US Air. I can probably have arrangements for them to get to Sugar River.

I'm subscribed to the thread or you can PM or email direct at [email protected].
 

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Discussion Starter · #3 ·
In 16's you can get just about anything thats is available in 12's....except Vee's. Of course you aren't going to find extra soft GP slicks or rains. But, the Europeans take their scooters adn 50/125 cc gp replica bikes pretty seriously.

Here's the tucker rocky tire finder page for 16's....page 111. And thats only the list they carry.

http://www.powersportrider.com/cgi-bin/zcatjpg
 

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Discussion Starter · #5 ·
Now that I have some 2.75x17's to compare to, I'll weigh them monday on the shipping scale at work (I'm curious myself)...I doubt my bathroom scale will have enough accuracy to capture the difference. But due to tire/rotor sizes and such, they still won't be "apples to apples" so to speak.
 

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Discussion Starter · #7 ·
Here's the comparison of the front wheels:

16" Mag front, 90/90 tire with a 260mm rotor - 16.9 pounds
17" 2.75 sun rim, 110/70 tire, cr80 sized wave rotor - 17.7 pounds

So the mag front is actually lighter...even more so if the rotors were the same size....but as I mentioned, its not apples to apples becuase of sizes.

And being a smaller diameter it less of a HP drag besides....maybe I should keep them...
 

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can you tell us what the axle diameter and or bearing dimensions are?
most bearings are stamped- for example- 6202
also- the width of the mounting space from bearing to bearing is... F/R

doesn't need to be exact- just a close range to use as reference.

the rotor spacing is an issue as well...
 

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Discussion Starter · #9 ·
Hey Mookie...you are sure hard to please...

Front and rear wheel are both 15mm ID bearings (same as the rear of a cr85). While not marked, they measure up as a 6202

Front wheel bearing width (outisde) - 3.925-ish
Rear wheel bearing width - 5.375

Here's what I was planning for fitting on my cr85....

Rear - would need roughly an .080" spacer on the caliper side. I was going to cut the OD of the rotor down to match the CR. I was going to mill down the mounting surface for the rotor to get its lateral placement right. The sprocket seemed to line up well, and another spacer for the sprocket side. The bolt heads for the sprocket were close, but switching to a pan head allen would give more insurance....or pocketing into the sprocket was possible also.

Front - something needed to be done to get it centered - it needed to go about 1/4" toward the caliper side. Perhaps a 6002 bearing or milling off some of the fork leg axle boss. I was also expecting to have to take down the rotor mounting surface on the front wheel as it and the screws would be close to the fork leg after getting it centered...perhaps a different style screw head would suffice. I was going to have the front wheel spacers make up the axle diameter difference so I could go back to dirt wheels....machining the fork legs for a larger axle crossed my mind.
 

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:popcorn:
 

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Discussion Starter · #15 ·
well, at least this is free bumpage.

Mookie - if you are coming to USAir or Road America, I can swing by there and bring wheels along to look at...but my motor will not be reassembled by Tuesday/wednesdya next week so won't be riding. Mike travels down to sugar river and MKE and I think I could put them in his truck if I ask nice.
 

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well, at least this is free bumpage.

Mookie - if you are coming to USAir or Road America, I can swing by there and bring wheels along to look at...but my motor will not be reassembled by Tuesday/wednesdya next week so won't be riding. Mike travels down to sugar river and MKE and I think I could put them in his truck if I ask nice.

the trip to the national will deplete my mad money supply....:rolleyes:
 
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