[Top Down]

Don't want to change the standard 27t crown but advised 10t pinion needs changing to improve acceleration and braking. 

Suggestion was 9t but I have a LOT more brass 8t pinions available so question is, go with the the 8t, which I have more of, or the suggested 9t.

Is the 8t more beneficial anyway on a track with a 30' straight?

[Kevan]

Yeah try the 8T, rollout will be longer for a truck as the tyres are much larger diameter so car gearing won't work as expected.

[Phil Kalbfell]

We run 9 :28 or 9:29 with tyres sanded down to about 25mm.
This was the common gearing for the Proxy trucks some years ago.
Most if the Proxy trucks were very heavy, around 160 grams.

[Top Down]

Just about spot on with the weight then. 163-166gms across all four. 10gms added up front behind the guide and 5gms either side, slightly ahead of the motor. 

I'm sticking with original tyres, which I haven't touched yet, so 25mm sounds like a good reference point. 

I have lowered the front end by about 4mm by extending the axle slots up into the wheelwells. 

Gearing is what I had most readily available at 8:27 or 3.375:1, although I COULD at a push change that to 9:27 or 3:1 - but I'd want to do that before gluing in the motors and axle bearings, so maybe I'll run them on the club track before doing any more in that area. 

Braking has definitely improved as it was previously non-existent.

However there is one odd issue. 

A couple of the trucks will occasionally do a 180 on a curve and gallop off in the opposite direction! Seems to be no travel limit on their guides but I can't see any difference between the four, all having stock sprung Fly guides!

[WilkFrisk]

If you've got a bunch of 8t pinions, give them a shot. It might help with acceleration on that track.