Tire question?

No, it is a Heathkit hilltopper. The info I got was wrong. The rear rim is 12 1/2 " wide on the axle support tube. The rim is 8.50 inches wide x 8" in diameter.
I bought the tire on a recommendation which was wrong.
I cannot convert to a CT200 as the rear end is much wider than the Coleman by several inches and the drive sprocket will not align with the jack shaft.
Can you make a 19 x 7.00 x 8 tire fit a 18 x 8.50 x 8 wide rim?
YES it will fit. It will just take some creative manipulation.

You will need to make the rim stable where it will not move or rotate while you do this. It really needs to be locked down to a table or a tire changer. A tire changer is best as it allows the tire to be free when you are pushing down. Cut some 2 X 8's or the like to act as a spacer if you need to do this on a flat table top. The trick is to get the rear bead to bite on the rim. I have been successful at this by using WD-40 to mount the tire onto the rim and then either clean the rear bead which is a pain or just leave it overnight for the WD to dry. Once it is clean twist the tire as you push it down onto the rear taper of the rim. You have to get it to bite so that you can pull up on the tire to seat the outer bead without the rear bead coming loose. It usually takes a couple of tries but can be done with a little patience. Its a pain but once you figure it out its really pretty straight forward.

You can do this with a vice if you have a couple of bolts to clamp in the jaws straight up and then bolt the wheel down using the lug holes.

I mount ALL tires with WD big or little. It works great and goes away all by its self. Plus you never have rim rust issues from water based lubes. I mounted a set of tires on my truck while I was in school and they had this "super duper" tire lube. Slick as snot for a couple of months... We road force balanced the tires and you have to mark the tire where the weight goes. And then adjust it until the machine is happy. Well the tires ended up rotated probably 8 or 9 inches after about 6 weeks. Still balanced unbelievably but the marks on the tires are nowhere near the weights anymore... Had to constantly air up the tires until they stopped moving when this junk finally dried.
Here is my concern, please bare with me as the tire, once it has been mounted cannot be returned and it was not cheap.Being retiredd on a fixed income, I hate to throw money away.
I removed the original tire from the rim,which was a very good thing as the tire was rotten and the rim was badly rusted on the inner surface of the rim.
I was able to remove all of the rust with only one pin hole found in the rims surface which I was able to seal up.
The rim will not hold air for a tubeless tire, it was never designed to do so. I have a heavy duty 18x8.50x8 rated inner tube which should seat the beads.
The original tire is 8.50 " wide fitting onto the rim which is 7" at the bead seat.
The new tire,at rest is only 4 1/2" wide at the beads ( uninflated) The tread width is just slightly over 6".
The diameter is not an issue ( 19 vs 18")



Rob cut some scrap wood that will hold the tire bead at the 7'' width of the wheel and then get a better idea of the tire fit. The bead is always narrower on a new tire as they usually get stacked instead of racked on the tread. This just flattens the section width and closes the bead. Space it open and look again. You can mount a tall tire with 6''s of tread width on a 10'' rim with no issues so your 6'' on a 7'' rim should not be an issue. You should actually like the 6'' tire on a 7'' rim as it will be more stable through the sidewall giving less movement with lower pressures. Should handle your terrain better.
I cut three pieces of wood to 6 1/4" to comp for the tire wall thickness and eyeballed the expanded tire to see if it would fit and seat the tire beads. It looked like it would work. I mounted the new tire and inflated / deflated the tire several time, each time banging the tire on a hard surface to allow the inner-tube to fill the tire properly with no folds or pinches.
I then took the tire up to 28 PSI and ran the bike up/down my back road several times at different engine speeds making sure to hit as many rocks and boulders as possible to help seat the tire beads.
I then dropped the tire down to the recommended tire pressure of 7 PSI and repeated the trip on my back road. ( 6 ply rated tire)
I then climbed a very steep hill to see it the tire was spinning on the rim, and it was not.
The rear tire has much better control on leaning the bike into a corner. It can get a little squarely if one of the tire lugs hit a large loose rock while in a turn. Just something for me to remember in the future.
I want to thank FOMOGO for convincing me to try the tire as it really looked like it would not fit the rim.
The rim is exposed on the left side of the bike a little and that too will have to be remembered as getting a replacement rim is darn near impossible these days.
I'm hoping the new tire will give me the traction the original lawn mower tire could not.
The tire is 19 "vs 18" in diameter. The top speed of the bike was increased a couple of MPH, which is a plus but were I ride your not going to be riding flat-out anyway.( 57.15" roil vs 60.32" roll )

New vs old tires

New tire mounted on rim and inflated to 28PSI


Tire mounted back onto bike and inflated to 7 PSI.