Gearing for stock classes
 

Hello there, I just got a x4 pro and wanted to run 17.5t non boosted class. However I couldn't get the gearing right with the 85t spur, are there any other spurs which fit? Currently need a 5.5-6 fdr according to the guys that run.

Looking at a gear chart

Your gonna need a 40t pinion to gain a 5.52 fdr or a 36t for a fdr of 5.97

The spur for the x4 seems the same style as the Mad Rat/Mad Monkey which are 80t so you could go 38t to gain a fdr of 5.47 or 34t for 6.12 fdr

Search for Mad Rat Spur (JE Spares) and there should be a pic of the MR/MM spur

Hope that helps?

The problem is that it looks like the biggest pinion I could get in there is a 25-28t. And it doesn't look like a 80t will be small enough? Is the internal ratio 2.437?

Thanks for the help.

If that car uses the same layshaft as a Mad Rat you can use t4 spurs which are available in 78t. I think a 75t is also available.
Losi Kevlar Spurs also fit.
Again, if the transmission is the same as the Rat it's a 2.6:1 ratio.
When I had a 80t spur fitted to my MR the largest pinion I could fit was a 30t unless I slightly modified the motor plate.
This gave me an fdr of about 7:1

But my car is the x4 not the mad rat, the 4wd Ansmann car.

Sounds like you might struggle getting the fdr required for that type of motor without moding the motor mount/a spur from another buggy!:confused:

I got 7.1fdr lowest and am trying an x12 with max timing see how that goes.

You can just get a 28 in there but with a bit of modification the 80 from the madrat will go in and you may just get a 32 in there

You can get the AE spurs to work BUT it takes a fair bit of modifying :thumbdown:
PM me if you want instructions.