130/80-18 instead of 140/80-18?

" Looks too small and wimpy "....... M8, I buy my tyres to ride on not look at aye bro?
The 130/80 will be a little bit lower in height and obviously 10mm narrower across the tread but will work fine, infact you will probably get a bit quicker easier steering ( as the 140 will be pushing the front) and better traction everywhere except soft sand and loamy dirt.

I am assuming you have a 2.15x18 rim and not a 2.5x18.

I have been swapping between 120 and 130 section tyres on the rear of my 04 650 but I have the 2.15x18 rim.
I was getting alot less milage out of the 130 section tyres as they are pulled around too tight onto the 2.15 rim. 120 section seems best compromise....... But thats just my opinion on what works for me....

Bottem line...... Try a matched set of tyres (not T63 michy's are they?) that are designed to work with each other, its alot more important than a few mm's across the tread.

Ride on brothers...... Darryl.

Hey Bergini, how is the motoring going? I had to register to tell you this . The tyre is marked with its width and aspect ratio. This means 140 mm wide and (140x80%)=112 mm sidewall height . Also that 130 mm wide and (130x 80%)=104 mm sidewall height. Thus a 140/80 x 18 has a rolling radius of 340 mm. while a 130/80 x 18 is 10 mm narrower (about 3/8") and a rolling radius of 332 mm.(little more than 1/4") . I hope you can draw an overall formula for future reference from this? As it is a calculation we encounter numerous times throughout life when checking he tyre market for replacements. A further point to consider therefore is ,should a higher pressure be run in the smaller dimension tyre(FAIRLY HIGH @36 P.S.I.) and only 22 P.S.I. in the larger of these two you will actually arrive at a larger tyre by diameter (& raduis) in the smaller specification tyre in use ( physical application). due to the small difference in size nominated and of inflation pressures. Good luck with that,I think it may actually pay dividends to use the 130/80 in some trail conditions.

On my 2005 fs650e dirt tires I run a michelin starcross ms2 110/90/19 and love it. sure it's a little skinny but it hooks up great and turns better. besides who's going to complain that your tire looks whimpy, the guy riding behind you. 2nd place is the first loser.....

it takes me 15 min to swap out the dirt tires for my supermotard wheels. if you have a rear rim with the sprocket and rear disk and the front rim with a front disk, the swap is very easy. If you have to swap over the discs and sprocket it could take you a while.

I run the same gearing on and off road....15/38 with no problems.