Originally Posted by
hlucn8r
Hey mate at our local track up here we are starting at a 3.5 fdr for 17.5, I'm running 48p, 65 spur - 36 pinion. I find it is on pace
Which track is that? What are the approximate dimensions? I'm guessing outdoor...
Originally Posted by
CraigM
17.5 is boosted in Australia
Craig, it is for AARCMCC classes, but there are some variations between states as 17.5 blinky seems common in QLD and that's what they're going to run for their State Titles.
It sounds to high to me. I would first check with your motor manufactures recommendations, then start stepping up from there. I run a 17.5 LRP X12 in mine. Manufacture recommends FDR of 4.0 and I'm getting most success with a fdr of 3.82 or 3.89 (depends on track).
I'm using 64p gearing - Spur 96, Pinion 49 (fdr 3.82) or 48 (fdr 3.89).
In 21.5 (hobbywing) I'm using fdr 3.5. 64p pinion 49, spur 88
Both classes I'm running in Blinky.
Somewhere in the high 3's would be reasonable for blinky 17.5, depending on track size and layout.
At SMA (and elsewhere that runs AARCMCC 17.5), we run boosted 17.5.
Matt - the biggest factor in gearing for stock is your motor and ESC. There are guys who run close to 5.0 and guys who run over 6.0. Your "style" on the throttle starts to play a big part in the picture, because often the guys running lower FDRs are probably better on throttle control, so heat is less of an issue. If you combine lower FDRs with aggressive boost/turbo and tend to mash the throttle, you'll smoke the motor pretty quickly. Quite a few went up at the ACT Indoor Titles last weekend due to the extra strain that the higher grip puts on the motor. A lot of people throw too much timing too early at the motor and all it does it get hot. Quickly.
Also, some motors like to spin fast, so you gear 'em shorter. I ran an FDR of around 6.2 at Whalan last year and the darn thing was still accelerating at the end of the straight. That was with a Fanton Ion 3 and Tekin RS and it didn't get hot
The Hobbywing speedies tend to work better with lower FDR's than the Tekin.
What motor/ESC are you thinking of running? Once you know, go hit up the guys who run that combo. In a couple of weeks, I'll be making the switch too and starting with the Ion 3/TekinRS set. I'm thinking around the 6 mark, FWIW.
Needless to say, I won't be one of the quick guys