Gearing xb4 4wd
 

Hi! Could some one suggest a starting point for gearing for medium / large outdoor track running a 6.5t

Thank you

18 or 19 with kit spur (xb4 2014).

gearing
 

I use 19 with kit spur at my track "Torch" which is an astro track. Works great for me.

Bernie

Oh Eco my speedo must be way off I'm running 23

You're not far away from me, I run 22 with kit spur in the wet and 21 in the dry, just check your temp is not too high

i would suggest , try to go with the smallest pinion possible, but make sure you reach your desired top speed on the possible long stretch . for example , i run a 20t with turbo function . if i run a 19t i will have not enough top speed on the long strait at my local track.

At silverstone indoor I was running a 19 as people said it was right but I lacked both punch and speed on the straight with a 6.5 speed passion.

I then went up to a 21 which was better and kept increasing until the temps got to high but I ended up on a 23t which I use indoor and out. Indoor I added boost but outdoor I don't run any extra. This is at Coventry which is a big outdoor 1/8 track

Thermaling
 

Help required please

We have recently moved to the XB4's running them in 4wd, I have 2 buggies both with 6.5t orca motors, orion R10 pro, I am running a 19t pinion on stock spur at surrey & Hants, however if the driving gets a bit aggressive on the throttle side the car thermals:(. At both Silverstone & Telestar I ran 21t pinion and the same result. I moved to an 8.5t orion motor and it has been better but not 100%. Both cars drive trains are free with no binding with the pinion removed, Is there something in the meshing or the slipper I am getting wrong?

Any suggestions please

Thanks in advance

Orca TX ?

I run a 20t on mine, it did get hot but it won't thermal on a run, maybe lower the punch a tad and remove any timing/turbo, I'm on 5 punch on my XB4 2wd but I use an Orca speedo (with fan) with a 120deg thermal cutoff.

I put ceramic bearings and alloy plate on my motor and lost 15deg overall.
I'm still considering running a 19 to lower the temp a bit