Rear tire sizes info.

[dragxs11]

I know that I'm not the only one trying to get the widest tire I can jam into my swingarm, so I did a little research and I thought what I found might be useful to some other people. First of all, I was bummed out to find that my last new tire (130/80h/17) was narrower than my fathers 130/90h/17, and my project Special fills the swingarm well with a Cheng Shin 130/90/16. So I realized that a 130 varies in width. I bet this is why some of you have said that you can get a 140 in there and some say you can't. Bridgestone has a great site for exact sizing. It shows the tire widths to a tenth of an inch. My dads Bridgestone Spitfire s11 is 5.3 and has a little room to grow. The narrowest bridgestone 140/17 has a width of 5.7, so it might barely fit. Anyway, I ordered a bt45 130/80h/17 with a 5.2 width and I'll see how that works out. Unfortunately I couldn't find the same info for my current Metzeler, so I just had to eye-ball a tape measure and say that it's about 5.0. I hope this answers some questions for you guys as it did for me.

[TopCatGr58]

Hey there DragXS11,

As I understand it, the width varies by manufacturer and tire style also. The Dunlop 491's I have on mine, 140/90/16 seems to be very close to the 5.7" width of your Brigestone 140/??/17. The center rail for my trailer is 5.5" wide, and the tire was slightly compressed/squeezed into this space, rubbed on the sides a little, but I wanted a snug fit in the trailer. I'm running a Special, but I had just checked the part #'s for the trailing arms and final gear boxes for the standards and specials, and they are the same #, so the space should be the same for standard or special! Also, just FYI!
T.C.

[dragxs11]

The big point I wanted to make is that a 130mm can vary between 5 and 5 1/2". A 140mm starts at about 5.6". I didn't know that before and I thought the info would be useful. By my ruff measurements, a 5.5" should work safely, but a 5.6 or 5.7 could be stretching it closer that I may want to go. Unfortunately, I couldn't find a battlax that would fit my rim with a 5.5" width, and the only one with a 5.4" width was a 70H... to low profile for a bike that already is to low geared(I think).
here are some height #'s I found too that show the big difference in overall diameter(may vary a bit with manufacturer) for the bt45's
130/70-17.....24.3"
130/80-17.....25.1"
130/90-17.....26.2"

[Dennyz]

Keep in mind the 17" rim (2.5") is 1/2" narrower than the 16" rim (3.0"). The exact same make and model of tire will look fatter on the 16" rim over the 17".

It is possible to gain about 2-3mm by spacing the drive unit on the rim. This will move the rear tire to the right the distance of the width of the spacers (washers).

The swing arm can then be adjusted to the left to bring the tire back in center. This will get enough room for a 140 to fit and still clear the swing arm.

I tried it and successfully ran a 140.90.16 for a while. It was a lot of trouble for the small gain. A 140 still looks weeny on the XS (IMHO).

I won't be happy until I get a 150+ under there. It is my opinion that it can't be done (safely) without frame, middle drive, and swing arm modifications.

[Geezer]

Originally posted by Dennyz
I won't be happy until I get a 150+ under there. It is my opinion that it can't be done (safely) without frame, middle drive, and swing arm modifications.

Be sure and let us all know when you figure it out. I'd love to run a tire like that on either of my 11s.

Geezer