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Discussion Starter #1
Does anyone have one that wants to trade or have an 18 for sale?
USA Wisconsin 54144
 

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I have a set of original not reversed wheels, 18 inch rear. They have useful tires on them and come with a matching rear end. The front has dual discs. Have perfect fork set to match. Look on the site for pictures and let me know if trouble finding them.
Capt Frank
 

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Discussion Starter #3
How much and location
 

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Will these fit a cx500. I’m really just looking for a rear 18 that will be a direct fit
 

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Tony, They are the wheels shown on my avatar, not reverse Comstars. They are off a cx500. I ran them thousands of miles since I put them on the bike. You can pick up some RPMs because the tire that fits the 18 inch rear is larger diameter.
I have them in SW FL, 33907, crated with useable Michelin tires (was running them till last year when I switched to Turbo wheels). I have them crated with a rear end pumpkin to match. The crate is 220 pounds.
The front wheel has been modified for twin discs.
BTW, the bike won AMCA first prize with these wheels two years ago at Barber.
The rear will bolt right on. The front will need new dual brake forks which I have available.
I never liked my single disc GL500 front end. Not enough stopping power IMHO. So I changed to this setup I'm offering. After running it for 5 years or so I changed to Turbo wheels (with rear disc) and a front end from a 83 GL650.
Wheels, tires, brake discs and rear end $200 plus shipping.
GL 500I forks in perfect condition (new seals, no leaks, some small pitting which have been filled) (without calipers) and will bolt right on (may, may not need head bearings) are $100 plus shipping.
Capt Frank
 

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You can pick up some RPMs because the tire that fits the 18 inch rear is larger diameter.
This is not quite correct information. I've posted this countless times before but here it is again so that you will know too:
Honda originally specified a 3.75-18 (theoretical diameter = 25.5") for the back of the CX500 and a 130/90-16 (theoretical diameter = 25.2") for the GL500 and other 16" wheel models. The difference is about 1.2%. In other words, the rolling diameter of a 16" GL500 wheel with the stock tire is almost exactly the same as the rolling diameter of a 18" CX500 wheel with the stock tire so the difference in engine RPM will be insignificant.

If a 130/90-18 (theoretical diameter 27.2") will fit between the swingarm (some brands might but I wouldn't count on it) that would be 8% larger than the 130/90-16 with 8% reduction in RPM (6500 RPM becomes 6020 RPM) &c. BUT you would be mounting the tire on a rim far narrower than it is designed for so the contact patch could be smaller than that of the 3.75" tire AND there is also the issue of fatter tires being harder to lean into a turn.

If you change from a 130/90-16 to a 120/90-18 (theoretical diameter = 26.5") the 18 should have 5% larger rolling diameter with the subsequent 5% reduction in engine RPM (6500RPM becomes 6190 RPM) and a slightly smaller improvement in fuel economy. Most brands of 120/90-18 should fit and the handling should be better than with a 130 section tire so I believe this is the best compromise.
 

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Thank you Sidecar Bob, just like I said, only more detailed. Thanks!
I did notice an RPM reduction with the 18-inch wheel. Been too long and have forgotten how much but 5% would be my guess. Also don't know what tire I was running. It is a Michelin but I'm not going to open the crate to find out the size. I do remember it was a close fit in both diameter and width. It was an older tire. I bought it NOS, but it was still wrapped and looked OK to me so I ran it several years including an 1800 mile run to Big Bend and back.
At about a year or two later, I bought on this forum a gear set from a 650 and had to do some mods (inside lathe machining) to make it run but it lowered my RPM's almost by 1000. I now get 75 with 6500RPM's but around town, my gas mileage is down about 10% probably due to using more throttle making up for lower engine speed and higher load ratios. I don't mind because a bit more fuel results in lower head temps on hot summer days, something I learned in the aviation industry. On the highway, even at 80 or 90 I can still downshift when needed to get more power for a long hill, like in West Texas. Highway mileage is comparable to what others report for their unmodified 500's.
All's Well,
Capt Frank
 

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I should add, I didn't change the 16 inch rear to the 18 for RPM's. I did it because I like the look of the spokes better and also like the look of the 18-inch rim far better on this bike.
 
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