6 inch rear wheel question

[airhead749]

Picked up some Marvic wheels but got a 6 inch rear wheel with the set for a 749. Been reading a lot of contrasting viewpoints on this subject. Anyone have any experience running a 180/55 or 180/60 on a 6 inch wheel or should I go to a 190/55. Seems like some people say its a non issue and others say that you should stick with the manufacturers recommendation to get the best geometry for the tire and that a 180 on a 6 inch wheel will flatten the tire and have a negative effect on corner grip. Thinking about switching to Dunlop since the manufacturer that I have now does not offer a 190/55 at the track. But, is it worth the trade off of loosing the nimbleness of a 180? Thanks.

[Paul_E_D]

Try it out and let us know what you discover!

[CBR929RE]

I'd worry less about a 180 vs 190 and worry about the 6" being off center since the bike was designed for a 5.5" (if I'm reading between the lines correctly). has that been adjusted or is the Marvic made to fix that issue?

[airhead749]

I'm pretty sure the rite spacers were provided for the 749/999 but the first thing I'm gonna do is get a sprocket on there and check alignment. My biggest concern is which tire on the 6" wheel provides the largest contact patch at full lean and/or best handling.

[CBR929RE]

biggest contact patch varies from manufacturer to manufacturer based on construction. a 190/60 Dunlop GPA may or may not have a bigger contact patch than a Pirelli Supercorsa 180/55. its really hard to give a definitive answer because everyone puts a different load on their tires than the person next to them.

[airhead749]

I hear that, guess I'm wondering how absolute the manufacturers recommendations are for particular wheel widths and how much wiggle room there is. Thought maybe enough people have experimented with that to shed some light but I'll probably have to do my own experimenting. Just don't want to find out I picked the wrong size tire on my head.

[Paul_E_D]

Correct, you have to find what you like. All those tires will work on a 6" rim. If one is a little stretched it's not going to dump you. It likely won't dip into full lean as easily or something. You really have to try. The "good" news is that tires don't last long in this category. LOL

[SVRACER01]

Wirelessly posted (GS3)

Personally, I would probably run the 190 at nhms just because the profile of the tire would stay as intended versus "stretching " a 180 on there. With that said I would probably opt for the 180 at someplace like njmp where stability at higher cornerspeeds would be relevant.
When I first started racing I was running (on my sv) a 120/60 and a 150. That bike never turned faster. It was great on the track that I ran in AZ but it was a bit too much at nhms so I eventually switched to the stock tire size.

[airhead749]

Well, I talked to a Dunlop rep and he said pretty simply that their 190/55 race tire is the same width as the Pirelli 180/55 race tire. That must be why those manufacturers don't offer those other sizes respectively in their race tires at the track. Go figure. So I guess its a wash. He actually recommended I go to a 200 but at 105 hp at the rear wheel I think thats overkill for Loudon.

[SVRACER01]

Wirelessly posted (GS3)

Its less about width and more about profile of the tire when mounted.
A 200 may be a bit more pointy and therefore change directions faster.

[TTD]

As mentioned, the 180, 190, 200 designation is an estimate. Stand all three next to one another from different manufacturers and you'll see a wide range.

If you wanted to run a Pirelli tire, the new 180/60 is the way to go. It is wider than the 180/55, and will fit nicely.

Bottom line... don't get hung up on the numbers on the sidewall!

[KB]

Size doesn't matter.

[ZX-12R]

FWIW, my 12R has a 6" wheel and came stock with a 200/50 which I never really cared for due to it's sluggish handling. I've also tried 180/55, 190/50, and 190/55 and have liked the 190/55 the best so far. The 190's gave me the turning characteristics I was looking for. The 180 was better than the 200 but I was never confident on it near the edges.

The 749 is a lot lighter and less powerful so your mileage may vary!