roll out

gotnitro · October 21, 2009, 03:47:45 PM

hey what was the roll out for brushless last year. i have a 74 tooth spur and ordered a 35 36 37 pinion because a 29 tooth pinion wont reach the teeth.

Blake · October 21, 2009, 04:39:57 PM

It's very dependant on your motor timing (either on the motor endbell, or in the ESC). I think somewhere around 75mm of rollout is a good starting point.

12th Scale Rollout in millimeters = (TireDiam x Pinion x 3.14) / Spur

Ex: (46mm x 37t x 3.14) / 74t = 72.2mm

Blake

gotnitro · October 21, 2009, 05:44:07 PM

thanks blake

RC51 · October 21, 2009, 06:09:59 PM

... and it depends on 4-cell or 1s ...

P.

jarrodH · October 21, 2009, 11:16:16 PM

so would a 1s car be lower, like a 65 or so??

jarrodH · October 21, 2009, 11:17:42 PM

Quote from: jarrodH on October 21, 2009, 11:16:16 PM
so would a 1s car be lower, like a 65 or so??

sory ment higher..like 78 or 80?

Blake · October 22, 2009, 02:57:41 PM

Yes, I think they gear 1s cars slightly higher (larger rollout, more millimeters) than 4-cell cars. But I don't really know.

Keep an eye on your temps.

And don't go buying every single pinion gear just yet. Wait until you know what you need.

Blake

Melbatoast · October 25, 2009, 11:03:31 AM

I learned my lesson in trusting a single post from RC Tech - "We are seeing our rollouts for 17.5 1-cell in the 95-105mm range, while 13.5 1-cell is in the 80-90mm range."

I started at 98mm and ran way, way too hot. My car is also 70g overweight, but I still don't think it's realistic. Ran into the same problem with touring car, the gearing info found on those forums is weird.

From a somewhat more trustworthy source: http://www.rcracechat.com/vb/showpost.php?p=381377&postcount=107

"In the USA, with the latest software, the 17.5 guys are on about 90mm/rev, and the 13.5 guys are about 70mm/rev As a guide, for our usual 46mm daimeter rears, that's a gear set of 47/76 for 17.5, and 36/76 for 13.5!!"

I ran 44/78 for 85mm my other two races and seemed alright for speed and temps.

Matt S · October 26, 2009, 01:23:27 AM

remember, alot of people run 1/12 on a way more open track.

dajracer · October 26, 2009, 09:10:24 PM

85 seems to be the number so far. Craig, Blake and myself were running 85 or close to it.

Blake · October 26, 2009, 11:03:53 PM

Yeah, I was 47mm tire, 84t spur, 46t pinion, for a rollout of 81mm. After the main, my motor temp was 135F.

My motor endbell was at 0 degrees timing, and I had 30 (MAX) degrees added via the Tekin speed control, and I had the Turbo Boost setting at 20 (MAX), with the minimum 0.5s delay.

Blake