you can get a motor hot by either being geared too small or too tall.

You need to determine which way you are at right now relative to that motor.

If you are basically at the higher end of your throttle range most of the time around the track, I would look at a bigger pinion / smaller spur gear.

If not, I would go the other direction.

These motors sound more rpm-ish than the VST series.

Well I have pinions 18-33 and a 72/75/78 spur. I would just think for a 2wd sct That 72 spur would be low

again, where are you topping out down the longest straight?

What are you seeing for around the track performance as far as throttle range you are mostly using?

It allmost doesn't seem like it's topping out. It's still gaining speed until I let off down the straght. And I am basically full throttle the whole race

okay those two seem contradictory?

To me at least I would think if its still gaining speed down the straight, then I would think I need to go with a bigger spur or smaller pinion.

If however I was going full throttle pretty much around the track, then I am under geared and need a bigger pinion / smaller spur.

This is all assuming that the motor is functioning properly.

I'm going full throttle from a lead finger. And we have good grip. Not because of the motor. I do let off here and there but the track has a good flow to it

yeah to me if I find that in general I am at the higher end of my throttle range, I would see about going with a smaller spur bigger pinion personally and check temps after 3 minutes to see how they are before the change, then after the change.

socal23, I for some reason thought you were running a stock buggy. My bad. Now that I have that straightened out in my little pea brain, I'm thinking you are probably overgeared and need to step down a tooth or two. I've actually found that Cain's method of setting the gearing for the longest straight works pretty well. Let us know what you find out.

all credit to the the Late Big Jim. It was one of the final things he told me about when I was having issues with gearing and I was in contact with him on a semi regular basis. Its too bad he passed away, it would have been interesting to see his take on the motors nowadays, etc.

Yeah. I think I'm going to run 78/22 and work my way up on the pinion. The 25th pinion I have is wore out and didn't think to buy another one as I thought it was binding issues but also my motor plate wouldn't let me run 75/24 the gears would not mesh. Tried to mill out the part a little Saturday night but decided against it as I did not want to widen thr holes and have any up/down play. So i will put a 78 spur on and start with the smallest pinion I can and go from there.

socal - do you know the gearbox ratio of your car? With a 2.6 ratio (AE/XFactory) I typically run 75/28-25. Factors that come into play will also be motor timing and rotor being used. More motor timing - less pinion, or, Less motor timing - more pinion. Every motor has a sweet spot and it can change a little as the rotor wears out. The heat cycles will at some point lower the magnetic strength, which changes how you need to run the motor or replace the rotor. From your signature - looks like you run the Durango - but I apologize I don't know the transmission ratio.

Also keep in mind that factors like battery (power and resistance), and driving style can make a big difference as well. Stock class racing isn't won on the straights, it won by getting through corners quickly and efficiently. Carry more corner speed your already going faster as you go on the straight -- your car/truck looks faster.

Hope some of that helped. Please PM me if you have more questions about our products.

Durango has the same internal gear ratio as a sc10. I understand where your getting at with the driving style. Last week I ran a trinity killshot double torque 17.5. Gearing was 75/26 timing was around 50* after a 5min heat it came off at 160*. This was with a 5300 stick pack. Now last Friday I put a be 17.5 with stock rotor at 10* and same gearing 75/26. Ean It For About 5min And It Felt lazy. So i went to the pits to check on it and it was at about 180* . I pulled the pinion off and rolled the gear box and tires exc to see if there was any binding. Nothing. I am very particular with gear mesh and I made sure it was good and it was. I upped the timing to about 30* to see if it would make a difference. Set a timer for 4min. Pulled it off. 190*. At this point I was thinking maby esc settings but in blinky mode there isn't much to change. Looked though it with the ez link and let it cool down. Set timer for 4 min and went back out. Hit about 179*. At this point I had convinced myself it was something in the gear box. I tore down the rear end cleaned every inch of the gear box and wiped clean all of the gears inspected the bearings I even took the gear diff apart and threw away the gears and put fresh ones in, cleaned and re filled the diff. Put it all back together and another 4min. 178* at 4* timing. So i figured maby bad rotor or needed more torque. Bought a brand new 12.5 ht be rotor and installed it. Set timing at 10* and a 4 min timer. 175* in 4min?? By then the races were going to start and I had no more time to test and I hadn't brought my spur gears with me. So i dropped the punch down to 80* and tryed to be as flowish as I could thought the night. Each heat it came off around 175-180* . Most other guys are running other brand 17.5s gearing them at 75/28 and coming off about 160ish. And I am usually top 5 A- Main and ended up 2nd in the b main because 2min into the race the motor would start to get lazy on me.

((Also forgot to mention that all this testing was done with a 4300 shorty pack, even less weight then the previous outing))

to be honest if the other motor had no temp issues and the new one did, I would think its nothing in the gear box of the vehicle personally as that part I would think would be consistent.

You mentioned gearing for other vehicles for other 17.5s they are running, so i am assuming you also have some durangos to go off of for your settings right and they are running torque based motors?

there is another durango he runs a reedy 75/27. And most others are running sc10's with the same internal gear ratio. Running d4's and reedys as well. D4 has plenty of torque without the 12.5 rotor and the reedy Mach 2 comes standard with a 12.5 rotor. So i know my gearing isn't far off. As to why I tested the stock rotor and the 12.5 ht rotor. I have ran a handful of 17.5s over the years and I really like viper products. The r be esc is very smooth and stays cool and the xpert servo I have in my truck is fast and strong. I never picked up one of the old orange/red 17.5's as I was told they just wernt the strongest motors. But when I saw they had released a BE 17.5 with option to use different rotors I could not wait to finally pair up a viper motor to the rest of the package. I'm not going to give up yet. I Orderd new idler gears and a new layshaft set, a new gearbox and a fresh 78t spur. Orderd a new bfast ball diff and a new ball diff ring gear. I dought I need any of it but I want to fully give this motor every opportunity to shine. I'm going to replace the large bearings on the diff and rebuild the idler gear bearings and inspect the motor bearings as well. Pull all the wheel bearings and clean the cvds. Going to start with 78/23-24 and see where That gets me.

I have been happy so far with the 17.5 VST I got. don't have much use on it from what we are doing now (carpet onroad with 2wd buggies) but I didn't feel outclassed by any means against guys running a variety of motors. Managed to win the A-main with it.

If there are other guys with durangos there I would ask to borrow a bigger spur if hey have it even if its say a 81 or 84T spur.