I was at the factory a little earlier today and went and found Mark to discuss this. I'll give Mark his dues as he stopped what he was doing and we went over to the workshop.
The belt tension guide might work but then we'd need to make sure they were all the same scale so we opted for the simple solution. We looked at what parts were readily available but drew a blank given the weight needed.
I've got home thins evening and looked around for some weights and found the remains of one of the kids project trebuchet which had 4 x 2.5kg weights on it and a hook through the middle.
After a little bit of working it out I managed to suspend 7.5kg from the top of the belt and had a deflection of 3mm.
I rolled the car back and forth to take out any tension and then using a piece of masking tape marked the position on the splash guard.
I then placed an allen key on top of the belt and suspendend the weight either side of the allen key with two zip ties and measured the distance to the tape line.
My BB was fairly quiet but was too loose as it kept pinging the splash guide when driven hard. I think my belt is now too tight and has started whining under the new tension.
