1000-5M-18 BELT for big wheel models only such as Chuweng Raser "Big Wheel" & xcooter thunder & Salorr & Star II & Grizzly & PanthR & THS 04, THS 05. and others using 102 tooth 5m wheel sprocket This belt will fit our "Big Wheel" Scooters, BUT!! We have even found that slight Shimming to Xcooter Thunder. Atx 1000 a.k.a. Raser Big Wheel a.k.a. PanthR models that have 102 tooth aluminum wheel sprockets with lip out can be shimmed behind sprocket to allow for running even 5m-20 belts. Not sure about Salorr Big Wheel model using 5m-20 yet without fipping both sprockets and maybe replacing wheel sprocket from plastic to aluminum 102 tooth sprocket from Chuweng.