Here, an inexpensive upgrade on eliminating that narrow 130mm and getting a 150mm on your stock 3.25" rear rim.

1. Purchase a 1 1/8" wide belt which matches the length of you stock 1 1/2" belt.

2. Purchase a 150 x 16 tire of your choice. That is the largest tire you can mount on your stock wheel. I initially tried a 160mm but could"nt get the bead to seat/seal.

3. Use your existing pulley but follow the these suggestions:
A. The 1 1/8" belt will give you approx 1/4" clearance between it and the tire.
B. You must carefully align the belt on the in the rear pulley.
C. when adjusting the belt tension make sure you set the right axle adjuster a 1/32"
further back then the left one. This will allow the belt to favor the left side of the
rear pulley and not float inward and rub against the tire. Be real carefull not to go
any more then + 1/32" as the bike will not track correctly and you'll chew up the
tire pre maturely.
D. Make sure you remove the caliper and pads, leave the caliper mounting bracket in
place.
You'll get a little PO'd trying to get the axle spacers in so dont give up, I've always
had issues ever with the 130mm tire.

4. Not sure if my pics will show up.
Its pretty straight forword and the 2 tire up size looks massive. Sort of like going from a
20ft boat to a 22ft boat.

5. This is the real deal, my trial & error. All the larger tire bull I've read is bull. Any larger
tire must be put on a wider rim.

Good luck and go out there and smoke a fatty.

 

Do you have a straight on shot from the back of the bike? Maybe a before and after shot?

Thanks

 

I follow your logic and have made that change myself, but I used a 1 1/8" pulley, instead of using your approach. The narrow pulley comes spaced with the belt away from the tyre, to achieve what you describe. I now have a Deuce wheel with 160/70 in......