Going to the Dark Side, Mounting a car tire on the FJR's rear wheel Options

[OCfjr]

***Note for people just finding this thread***

If you want to get to the interesting parts and skip all the chatter, here are some suggested posts to read:
Read posts #9, #22, #33, #103, #172(finally mounted a decent tire to ride on), #186, #188, #194, #199(first ride on the new tire), #201, #220, #234(first, wet, day ride), #333(multi-day trip report w/hooning in the twisties included), #337, #401(tire type/spec questions), #405(darksider #2 posts), #415 (13k miles on CT), #428, #434, #445(what to say to a shop for mounting/buying a tire), #481(front tire log info), #483(two up & weight talk), #488(darksider #3 posts).

Readers Digest Condensed version - #9, #22/33 on pg. 2, then skip to #172 on pg. 9 at bottom, #234 on pg. 12, #333 on pg. 17, #401 & 405 on pg. 21, #415, #488 on pg. 25.

Also, a FAQ now exists - FAQ

Start of original thread below.
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I tried to just start this in NEPRT, but you can't start threads there. I'm sure a helpful admin will move it for me shortly, at their discretion, of course.

I read about mounting car tires on bikes years ago. Mostly cruisers and HDs. I even rode an old Pan Head with one way back in the day. More recently I caught some discussion on one of the lists about it and read some more. Recently I decided to give this a try. At least to discover if it would work on the FJR at all.

I bought a used Cooper Zeon ZXS summer performance tire for cheap to test fit and today with DougC's help we mounted the tire and installed it on the bike. Below is a short report and some pics.
Apologies if you get this multiple times. It's going out to different lists.

So, things went fairly well. First off, it's a bitch to mount a stiff performance tire to a moto rim, even with the NoMar tire changer and three people, but it can be done. It takes all the tools you have though.



More tools stuffed in the tire

NoMar in use

And a 205/50-17 does fit on the FJR's 5.5" wheel, and fits on the bike, JUST. I think it just barely rubbed off the tops of some of the lettering on the sidewall with the brake caliper arm. There was about 1/8" clearance to the side stand legs as well. FYI, it rubbed a little when flat. :-( But not so much you couldn't push the bike around.

the bike

Ready to go test ride:


What did I learn? The car tire is wider than the rim, so mounting it requires more effort to get the first bead in the 'valley' of the wheel while you work the second bead on. And since the tire sticks out farther from the wheel, that means it doesn't like to sit flush on the NoMar pads. It's dished pretty good once you have both beads on the wheel. No need to seat the bead with high pressure, they are THERE. Possibly due to the rim design, the tire sticks out at the rim edge more than on a car. Not a problem, just an observation. Think rim protector beads X2.

For dismounting, it's very challenging to get the wheel lip onto the NoMar pad clips and locked in. I had to stand on the wheel spokes to exert enough down force to allow a second person to push the wheel into the pad clips and locked down.

I also learned to check used tires better for damage. :-/ The Cooper tire I bought for testing turned out to have two vertical slits in the side wall. Same side and they didn't leak with the tire inflated and just sitting there. They only leaked when the tire side wall flexed. I got a slow speed test ride in, but couldn't do an 'at speed' test due to the severe leakage.

The Cooper Zeon ZXS has very stiff side walls. It's a summer rated performance tire, so that was expected. Not much flex at 30 psi and one side would lift off the pavement when doing turns. I suspect a softer sidewall all season tire will not be as bad in this regard, but didn't feel it was a deal breaker on it's own, and didn't get the chance to play with different pressures due to the leaks. We could have patched it, but having learned 85% of what I wanted to learn, I didn't feel it was worth the effort to dismount the tire, patch it in two places, (making a total of three inside patches), and re-mount it.

What I noticed in feel is that during slow speed turns you can do everything you always could and it feels fine, traction wise, it's just that you get feedback in the bars when turning. A very noticeable pressure against you. You push left, it wants to keep going left to a tighter turn. You have to hold the bar position you want noticeably. This is parking lot drill speeds though. On the one short ride at faster speeds, (35 mph), I noted that the bar pressure seemed less and wasn't really that big a deal. Again, not a great test, just tooling down the neighborhood and making some swerves and a few turns.

I'm going to go ahead and order a new all season tire and give the Dark Side a try. I now know it will fit on the FJR and while handling is different, it's not so different or bad that I feel unsafe. There is just an adjustment period. I don't think it's a big deal to adjust to the car tire at this point.

I'll post more when I have the all season tire on and have some miles on it.