1/12 forum
That doesn't really help. Why would I do that? What does that tell me about FDRs/rollouts? As a random example, a 72T spur and 47T pinion gives me the same ratio as an 84T spur and a 55T pinion. So why would I buy a larger spur when the same FDR/rollout can be achieved with the spur I have?
I'm not being a smartass but if you advise something like that, which isn't really an answer to my question then please explain why.
What is the reason for running larger pinions/spurs? I see a lot of people do it now so there must be an advantage but I can't get an answer as to what it is.
I'm not being a smartass but if you advise something like that, which isn't really an answer to my question then please explain why.
What is the reason for running larger pinions/spurs? I see a lot of people do it now so there must be an advantage but I can't get an answer as to what it is.
That doesn't really help. Why would I do that? What does that tell me about FDRs/rollouts? As a random example, a 72T spur and 47T pinion gives me the same ratio as an 84T spur and a 55T pinion. So why would I buy a larger spur when the same FDR/rollout can be achieved with the spur I have?
I'm not being a smartass but if you advise something like that, which isn't really an answer to my question then please explain why.
What is the reason for running larger pinions/spurs? I see a lot of people do it now so there must be an advantage but I can't get an answer as to what it is.
I'm not being a smartass but if you advise something like that, which isn't really an answer to my question then please explain why.
What is the reason for running larger pinions/spurs? I see a lot of people do it now so there must be an advantage but I can't get an answer as to what it is.
Tech Champion

Joined: Nov 2001
Posts: 7,191
From: Hawaii, USA
There are a few reasons. First if you change classes to a faster motor you aren't going to be able to move the motor back far enough for a smaller pinion to mesh. Another is gears are more efficient when there are more teeth engaged. And lastly it would have to do with how far forward or rearward the motor is in the pod and how that will affect grip.
As you may or may not know, brushless motors are a different breed of motor compared to brushed motors. They produce a considerable amount of torque, and that being said you'll need to covert the motors torque into speed. The only way you can really do this is by running a smaller spur gear (78) and bigger pinion (38) tooth. I've tried running a big spur (96) and (55) pinion, but as your rollout changes, so does your pinion. When the tires get smaller, you're rollout gets smaller, so you'll have to adjust for this with a bigger pinion. I've had situations with a big spur and pinion where my motor couldnt move any further back and wouldn't let me run a larger pinion gear.
Basically, bigger spur and pinion limits the amount of room to play with on you motor mount.
Basically, bigger spur and pinion limits the amount of room to play with on you motor mount.
Hello ya'll.
Below is a setup I've been running as of late.
Associated 0.40 mm front springs
4 shims under the upper arm
Standard track width 165mm
This setup worked well, but I decided to make a few changes to see how the car would handle.
Changes made were:
Increased to 167 mm track width.
1 mm shim between the upper block and bulkhead.
The changes made worked fairly well, handling was great, but it had no mid-corner steering coming off of the straight and onto the high speed sweeping corner.
I suspect, by widening the track width, and the 1 mm shim changed the camber gain quite a bit. Is there any why to keep this suspension setup the way it is and find another way to improve the mid-corner steering? Stiffer springs for example? Steering angle more swept back more? Or should I just go back to the original setup I had before?
Below is a setup I've been running as of late.
Associated 0.40 mm front springs
4 shims under the upper arm
Standard track width 165mm
This setup worked well, but I decided to make a few changes to see how the car would handle.
Changes made were:
Increased to 167 mm track width.
1 mm shim between the upper block and bulkhead.
The changes made worked fairly well, handling was great, but it had no mid-corner steering coming off of the straight and onto the high speed sweeping corner.
I suspect, by widening the track width, and the 1 mm shim changed the camber gain quite a bit. Is there any why to keep this suspension setup the way it is and find another way to improve the mid-corner steering? Stiffer springs for example? Steering angle more swept back more? Or should I just go back to the original setup I had before?
Tech Master
iTrader: (41)
Joined: Oct 2008
Posts: 1,325
From: Grand Portage, MN
Tech Fanatic
Joined: Jun 2005
Posts: 900
The track isn't big enough for temps to be the guide. More timing/lower ratio or less timing/higher ratio - work out which is fastest by looking at your lap times and 'difference' across the race. HTH



2991Likes