The HW 1S speedo is the best blinky or boosted speedo running now...its also the cheapest that comes with a built in booster.

Reedy Sonic, Thunder Power w/Green rotor or Revtech Maxzilla 17.5's are all excellent.

Run a roll out of 100mm in 17.5. That's a 56 pinion with a 76 spur with 43mm tires. Temp you motor after 2 min and gear up or down to stay lower than ~155 deg F. If you are at 100mm roll out and the motor is cool bump up the timing 5 deg at a time until you are around ~150deg.

Check your lap times as gearing up or increasing timing with no lap time improvement means you are over geared or over timed. You may never get to 150 deg if the room is cold.

If you are running on carpet cut your tires to 41.5mm F/43mm rear or your car will be traction rolling/lifting/diffing out.

I would start with a 24 pinion. If you post your speedo settings I can probably get you closer to what I am running. I am also running Orion R10 and a Orion 3.5.

Steve Dunn

Where can I get unmounted / untrued tires? Buying sets of mounted/trued tires gets $$$$. Thanks

Any track is doing vintage 1/12 racing? You know, 4 cell brushed, hehe...

these days - in the end - you'll end up paying almost as much as you would for mounted/trued tires. Mainly due to the premium that's charged for the exotic foam compounds being used these days and how few people sell those compounds in unmounted donuts.

NOOOOO, Do NOT go to 100mm of rollout in BOOSTED 17.5, the car will be a dog or burn up. If you have the murfdog 17.5, which I think is the same as a Reedy 17.5, and the LRP Stock Spec V2 ESC at full song on boost, gear about 70mm of rollout with neutral timing on the endbell, whatever comes as stock and reads zero. Set Torque/Feel at about a 3 or 4, five really only generates more heat, and in order to get more boost into the motor you will have to gear DOWN, not up, to get more boost as the LRP boost is RPM based, more RPM means more boost. I have run nearly this exact combination of ESC settings and spec motor, and it can run hard and pull RPM a long way, but it's not intuitive as saying 'gearing up gives you more heat and top end speed'.

So what's a good pinion and spur with 43mm tires to get a 70mm rollout?

42x81 comes pretty close. Get a rollout app for your phone, I think it might even be free.

Heres a great one for android

https://play.google.com/store/apps/d...eamusoft.gears

Sorry, I missed the Boost part. All we run around here is blinky.

I have 2 roll center questions, if anyone can help. It's been 10 years since I ran pan cars, and that was on an oval:

1: Where is the roll center on the rear of the car, on the middle of the axle, at the lower pod plate, or in some mysterious nether region I'm unaware of?

2: Does raising the hingepins on the front end lower the front roll center?, and won't this allow more roll? Will this be better in larger or tighter corners?

Thanks!

The rear roll center is the rear pivot ball... I know, super mysterious.
The front roll center is a function of where the angle formed by the upper and lower arms would meet, and how high that is. So making the top arm on a 1/12 car more flat would raise the front roll center.

1. Like Desert Rat said.

2. Raising the hinge pin does not alter the roll center on suspension with a fixed lower arm. Think of the lower arm as an infinitely long (pivot point to pivot point) lower suspension arm that is parallel to the ground. Changing the upper arm angle will cause a line drawn through it to intersect the lower arm's line at a different point. This is the instantaneous center of rotation. This changes the camber curve. Raising the hinge pin or lowering the outboard ball reduces camber gain. This along with the necessary increase in static camber to allow even tire wear will make the car feel smoother to drive.

Yes and No. The car rolls around that pivot, but it's not the rollcenter. If you raise the front pivotballs of the Links/T-Bar you will lower the rollcenter.