$4 to be exact.
I know the math.
I don't have the tools to perfectly drill out centers of a spur gear. It would just be nice if smaller spurs would be avail.

wonder if the mi4 spurs fit
http://www.racing-cars.com/sp/catego...nsmission.html

Where do you want to insert the slipper pad?

Wouldn't it be a good idea to use a body reamer for expanding the hole? Of course you would have to expand it carefully and stop at 8 mm.

Edit: I just had a go on a 72 and a 75 tooth AE spur. If you hold the body reamer straight and check the diameter with some calipers from time to time, it seems to work quite well. Of course, it is not absolutely true to the centre, but the deviation is not too big, approx 0.1 mm to max 0.3 mm depending on where you measure, and the pads and discs will help to centre it, too. To be on the safe side, I also ordered some AE slipper pads.

According to Muz, the layshaft will have a 8mm bore. This is not the same bore as Associated and Kyosho spurs. I think 80t with 17.5 or 13.5 will be plenty gearing around 7.5-1.

According to the exploded view and the homepage spare parts list, the spurs are identical to the CAT SX versions, i.e. 8 mm.

You are correct. I think Schumacher is thinking about alternate options for spur gears. It will all be resolved soon. I think the 80t is still going to be plenty for the 13.5 racer.

HI all
trying to set up a mates cougar.
He has a Nosram matrix with a 4.5 and a 9T motor, he wants to run the 4.5 cos he thinks he will go faster and thats better.
Anyway he has the standard 83 spur what pinion should he have if he runs the 4.5 and what pinion if he runs the 9T?

Thanks

4.5 ? Motor ? Thats wayy too hot for a 2WD.

Most of the fast lads here ( Euro A finalists fast ) use a maximum of a 6.5 in 2WD. 7.5 is normally enough for some tracks !

I got a 78 tooth spur from RW Racing for my Cougar, smallest pinion I can fit is a 22, not sure on the largest. I was just looking at a how to move weight rear-ward and this seems to have done the trick.