Pinion size
 

Hi does anyone know if different manufactures of pinions, are different widths. (Not the diameter which changes with number if teeth.)
My rwracing pinion is very close, near enough touching my top deck on my T4 13.

Cheers

If it doesn't touch then surely its OK?

what size pinion are you using?

Xray make some narrow pinions. Very good quality although a bit pricey.

Will be cheaper to get a smaller spur so you can run a smaller pinion for the same ratio.

Hi I am using a 48dp 69 spur with either a 37 or 38 pinion.
Reducing the spur and pinion size down, will maintain the FDR but does it effect anything performance wise or is it just the same ?
I could flip the pinon around but it then rubs on the motor mounting screws.

Thanks for your replies.

Performance will be the same. Small change in weight distribution as the motor will be further back, and small reduction in rotating mass, but nothing you're going to feel on track. Just don't go too small on the spur/pinion or you won't be able to get them to mesh.

Loads of people run the T4 in 17.5 blinky with massive pinions, so I'm a bit suprised it's an issue. If the pinion is centred within the topdeck gap and the rotor is properly shimmed (minimal play) it should be fine as it is.

Cheers, what do you mean by shimming the rotor ? Putting shims inside the motor to adjust the rotors position or shim between the motor and motor mount.

Shims inside the motor to limit the amount of rotor end-float to ~0.5mm. Most motors come pretty good these days, but sometimes the shims get lost during motor rebuilds.

I had the same problem when running 17.5T and using the same gear ratio.

I had the motor mount milled so to allow the motor screws to be recessed into the motor mount so then you can use the big pinions without the chance of it hitting the motor screws, top deck or lipo.

Just like what's used on the Xray T4 2014.

You can fit the '14 mount onto the '13 car, although a couple of narrow pinions is a cheaper solution.

The real solution is get a 13.5 and stick a 22 pinion and boost it up :)