Who's Right??

My 05 999S Ducati has 190 Pilot Powers on the rear with a 5.5" rim (OEM).  This being contrary to any and all info I have gathered for the proper application for said tires - rims etc.  Michelin states a 6.0" rear for their 190's.  What the h***is going on.  The edge of the side wall is verticle and near impossible to scuff in if that means squat.  But it took more than a bit of effort to get things scuffed in.  I think I should have a 180 on the rear with a 5.5".

Any advice etc. would be appreciated.  

That does seem strange, and your description matches when I squeezed a 190 onto my old ZX-9R that had 5.5 rims. It was a mistake and I was much happier when I returned to the 180. Which is what I suggest to you. Try a 180, it will almost certainly turn better, besides, they're cheaper.

I don't know why Ducati would do that.  

When we were at the press launch for the '05 999 I asked one of the engineers that exact question. He said that part of the reason they use a 5.5-inch rim is so that the wheel is shared with the 749, reducing parts count. It's also a tiny bit lighter, and the wider tire is a bit of a style thing too. He said that the bike was designed to work with that combination though.

We tried a 180/55 on a 999 at a track day once, and it didn't work so well. At another day we used the big tall Dunlop 190/60 DOT race tire, and that worked good although we had to add a link to the chain.

Definitely it's an odd setup and goes against a lot of recommendations from tire manufacturers and what we would normally suggest. However, in this particular case I'd go with using the same 190/50 as stock.  

Andrew, I know I probably don't have to ask you this, but did you adjust ride hieght when you used the 180/55? Theoretically you're looking and .3" increase in rear ride height with that tire.

Also, I'd like to point out that it's really lame of Ducati to do that. At the price you're paying, they can afford to put a 6" rim on the 999. If anything, the compromise should be made on the 749, not the big bike. Gixxers share more parts than anybike I know, and even they have different rear rims, and Suzuki's cost a hell of a lot less.  

Yep, we tried all kinds of things.

Whatever the explanation, you can't deny that the bike works good with the 5.5"/190-50 combination.

AT  

Hmmm, strange. Oh well, if it works, do it. That combination was certainly not desirable on my '98 ZX-9R, but if Ducati says it was planned for...