The rim itself is 3.5". So, depends on the manufacturer and tire you may be able to fit a slightly larger rear tire given that it's recommended on a 3.5" width rear rim.

I've read a lot about this and i've come to the conclusion that 140 is the widest you can get and not add a lot of height to the tire. going wider makes the bike noticeably less flickable as well.

I think flickable isn't an issue because you can compensate that with changing the steering geometry, ie lower the front a bit. But I think the 2008 already has less hp, adding extra rotational mass will make it less responsive. But, if freeway stability is more important then I guess you can live with that.

http://www.2fiddy.com/2008/07/larger-tires-150-on-a-250r/

Rear: Dunlop Sportmax Touring D250 — 150 / 70 / 17
Front: Dunlop Sportmax Touring D250 — 120 / 70 / 17

Nice! But I think 150 is kind of pushing it a bit.... :scooter

Plus it looks like the left part of the swing arm is slightly bent o_O

Plus it looks like the left part of the swing arm is slightly bent o_O

that could be because you dropped it....IMO....hahaha

Thats not my bike ...

Thats not my bike ...

I can tell. I think your bike is black right? haha.....Back to subject. I wouldn't want to make the back tire bigger. This bike is known for its agility, adding a bigger back tire would sacrifice that ability. If you use the bike for commuting on the free way then it would be nice to have, it would allow better stability and traction for the high speeds (yea 70mph is considered high speed for our bikes). In the end it all depends on what you use the bike for. I personally think 140 should be the biggest anyone should go. Keep in mind the bigger the tire the higher up the bike will be.