XRAY - Model racing cars

I drive my T4 only on carpet tracks in the winter. Currently I drive most of the time on a very tiny track (see attached image). I have looked into about 30 setup sheets for the T4 and some for the T3 and in 99.9% the drivers drive a spool. One fast driver at the track told me that I have to get a front diff (for the small track) and now I wonder if it is worth spending about 60 EUR (diff, putty and shipping) for a try or just keep on driving the spool. Whats your opinion?

I would use a front diff at your track for sure. Looks like you run 13.5 or 17.5? I also wouldn't lock the diff as much as usual. Maybe 200,000 cSt for a starting point. So you should get all the hairpins smoothly with even throttle applied for more cornering speed and smaller radii.

Thanks for the quick reply. You're right, 13.5/17.5 is driven by most of the drivers. I'll order the diff and oil and test. Many thanks!

It could be that you'll have excessive wear on the alu gear diff outdrives when using them in the front. Maybe with 200,000 cSt and 13.5/17.5 motors they could last but better would be to stock the alu outdrives as spares for the rear and order the steel outdrives for the front. I would try the alu ones first and check them every 4/5 runs with the above combination just to see how it works.

Thanks again for the hint. Just added the outdrives (#304971) to my order.

I have tried the gear diff today (first with 200000cSt and finished at 100000cSt) and it was way better than the spool. Thanks a lot for your hints!

The spool gives a lot more low speed and mid corner rotation. I also practice on a fairly small track and the gear diff is normally better there (with a hard putty) that is.

What diff is used in the front? Is it the same as the rear but flipped?