The issue I’m having is with the 70T/20mm pulley. The trans pulley change went exceedingly smooth so something had to gum up the job. I mocked up rear wheel to check belt length. Everything was going smooth until I started rotating rear wheel. Belt walks inbound until it is stopped by the sidewall. Pulled it back apart and quickly found my screw up. Stock 66T is ~29mm wide at axle and the 70T is ~15mm. Is there an OEM or Aftermarket 14mm Spacer to place behind the pulley? I’m guessing the thinner pulley was not from a 200mm swing arm set-up. If calculations are correct, with the Andrews 30T tranny and stock rear wheel pulley overall ratio is a 2.97 (stock is anemic 2.79) and the 30T/70T combo is 3.15. I hear tell of a 68T international pulley exists along with a 64T Japan pulley. Does anyone know if the 68T pulley is for a 20mm belted 200mm tire? And if so anyone know where I can score one? Sure would like to ride this season........

 

Which way did you rotate the tire?. If rotated forward like when you are riding. The belt should walk outward away from the tire. When rotating the tire backwards like when you are backing up. The belt should walk inward towards the tire.

 

Actually both directions. Did you see in picture the thickness difference of ~14mm? That missing 14mm has to be made up from between the hub and sprocket somehow for this setup to run true, right? Or am I over-thinking this?

 

What type of bike?

Dyna wise, I am running the 68T International rear pulley along with the Andrews 30T front. The hub of the 68T was .10" thinner than the stock 66T but the outer part of the pulley was .10" thicker so it seemed to offset the thinner hub and lined up well. The 68T is designed for a 1.125" belt but I am still running my stock 1" belt and it rides on the outboard part of the pulley - planning on getting a 1.125" belt.

 

200mm XBones. 20mm pulley. We're talking better than a half inch difference

 

Might have to get a pulley/sprocket spacer, not that uncommon: Ebay, Amazon, Demonscycle, CruiserCustomizing, etc.

 

the wider the tire the thinner the belt needed? And the rim is going to be wider so a pulley with less of an off set (thinner) would be needed? If I'm understanding correctly. It is normal for the belt to walk inbound when tire is rotated backwards. And also walk out when rotated forwards. If it walks inbound no matter how you rotate the tire then there is an alignment issue. the rear pulley is what guides the belt not the front drive pulley as long as they are aligned the rear pulley will guide the belt were it needs to be on the front drive pulley. As long as the belt is not rubbing the tire and the pulleys aren't shaving/wearing out the belt sides your good.

 

thanks for pointing me towards spacer - I tend to go "Dark" when I get frustermurated! Just ordered .500 spacer off ePay. one more piece to the puzzle in place......well by Thursday anyway