I've used blue and green belts in my XX4 and they didn't last long when I went to BL power. The first BL system I used was a Mamba Max with a 6900 KV motor. You can hear the belts skipping when you punch it specially the rear one. When I shifted to the Tekin R1 Pro with a 448 motor, the skipping was minimized but was still there. I was also running out of original Losi green belts so I had to find alternative belts to keep me running.
Fortunately enough, I was able to get it from a fellow XX4 racer who was in the same boat as I am. The rear belt we are using now is made by BANDO from Japan and the front/mid belts are made by Gates from the USA. It is used in Xerox machines (I think). They are black in color and have the same dimensions of the Losi ones. We've done some track time with these belts and they are holding up very well. There are three of us using these belts but the mid belt is still skipping a bit that's why I did the belt tensioner mod.
Here's a picture with the black and green belts for comparison. The rear green belt is toast with a lot of missing teeth in it. Sorry guys for the bad resolution of the picture. I'll try to get a better camera.
