Joost K.

Well... Smaller spur = higher topspeed & lower acceleration

So yes, you are right... Rollout = just a matter of pinion:spur:tire ratio...

BUT...

To get a proper rollout with a very small spur means often you need a very small pinion too.

The advantage of a larger spur (and therefore a larger pinion) is that there is less tooth-friction in the rollout and that is what you want on a pancar, smoothness...

So in order to get the rollout you want, always try to get to it with the largest possible spur and pinion to keep that tooth-friction to a minimum.

swerv512

iTrader: (21)

Lightbulb moment! That makes very good sense. Thank you.
I've only run 64P onroad - I'm a TC guy and TC pinions and spurs don't seem as susceptible to debris (rocks) as pan car designs, so what brand 48P gears do you recommend? I'm using an IRS axle with a xenon spur? now and the diff ring seems small. Will running larger (diameter) spur gears (48P versus 64P) mean that i'll need larger diff rings?

liljohn1064

iTrader: (17)

The diff rings and ball placement in the spur are pretty standard. You should be ok no matter which brand you run for rings, diff balls and spur gears.

G-rem

iTrader: (2)

Go with Kimbrough 48dp spurs, these are the only ones capable of managing Pan Cars torque, others are too weak

For your IRS axle, use TKO diff rings, these are the best for diff! And also ceramic balls, you'll get the smoothest diff with them

Joost K.

Almost all IRS style diff rings will do just fine. I believe that the TKO rings are already sanded which is good. Definately go with ceramic diff balls and if you can, mount a slapmaster thrustbearing or one similar...

liljohn1064

iTrader: (17)

+1 Mine are 48P Kimbrough spurs.

Joost K.

Definately Kimbrough for me too... Best spurs, good second place are RRP spurs...

Pro10noob

iTrader: (13)

Same as Joost
After switching to Kimbrough, never stripped a spur again.

Regards Roy

swerv512

iTrader: (21)

I have a serpent 84T 48p spur gear and the gear is almost as big as my rear wheel- but I guess I'm use to the compactness of 64p... Won't that make it more susceptible to rocks being so big?

1spunspur

iTrader: (1)

I have a TC and a pan car. The spur on the pan car seems to be in better shape than the TC. Go figure. I guess it's just random luck.

RoyU

iTrader: (2)

John, what size spur gear, pitch and teeth, are you using?

swerv512

iTrader: (21)

Maybe i've just been lucky because i've been on the same 64P set of gears for months in my TC and i run on mildly-prepped asphalt in a parking lot mostly. I'm gonna look for some 48P kimbrough spur gears.. All this 235mm talk has me neglecting my TC threads lol.

racenut123

iTrader: (32)

Its rare to kill a spur in TC because of debris. Its usually caused by a crash and motor moving.

BTW, do you only run at Brisbane?

swerv512

iTrader: (21)

Pretty much... Just getting back into the hobby a few months ago after almost a decade away. Looking forward to getting back into the race scene. So much has changed in the past decade lol. Brisbane is a great place to get some low pressure wheel time re-acquainting myself with setups and driving technique.

On another note:
I found some 48P kimbrough spur gears online. I don't want to get too big here. But I can get a 90, 93, or a 96T. Any reason one is better than another?

1spunspur

iTrader: (1)

TC's are great for bashing. There's a huge lot near my house my TC4 has taken a beating. Spur & chassis, the worst...I quit going there.