Gearing for SV

[westyguesty]

Can anyone suggested a starting point for gearing on a cougar sv, standard gearbox.
Two motors, 10.5 and 13.5, running on small outdoors track. It for my son to get used to befoer racing, not bothered about going that fast, jsut keeping everything reliable.

How do I tell if it's gear right, motor temperature ?

Thanks.

[RandomConflict]

I'd be after any information possible aswell. Recently got myself a cougar after making the switch from a b4. Currently using the standard kit spur, which is 83 tooth I beleive with a 24 tooth pinion on an 8.5 motor. I also have a 6.5 motor and would like to know anyone's reccomended gearing for this? The 24t seems to run pretty well at the moment on the 8.5 with no overheating etc. How hot can a speedo/motor get before it is thought to be overheating? Any info greatly appreciated.

[h0m3sy]

Originally Posted by westyguesty

Can anyone suggested a starting point for gearing on a cougar sv, standard gearbox.
Two motors, 10.5 and 13.5, running on small outdoors track. It for my son to get used to befoer racing, not bothered about going that fast, jsut keeping everything reliable.

How do I tell if it's gear right, motor temperature ?

Thanks.

83t spur with 21t pinion should be fine to start with on a 10.5, never ran a 13.5 so can't help with that one.

[ian h]

Originally Posted by h0m3sy

83t spur with 21t pinion should be fine to start with on a 10.5, never ran a 13.5 so can't help with that one.

That sounds very under geared to me. For the 10.5 you should be up around 27 or 28 if it fits with the 83 spur. I would reduce the spur to 76 or 78 and then start off with a 26 pinion and go up from there if temps are ok. Last time I ran a 10.5 I used 78/27 with a speed passion motor. Temps were fine.

[westyguesty]

So if I use that for a starting point, and monitor temperatures ? When I used to race gearing was controlled more by how long the batteries would last, without that worry now, do i jsut make sure everything isn't getting too warm. How hot is OK ?

[ian h]

Originally Posted by westyguesty

So if I use that for a starting point, and monitor temperatures ? When I used to race gearing was controlled more by how long the batteries would last, without that worry now, do i jsut make sure everything isn't getting too warm. How hot is OK ?

Depends on the motor really, Some run hotter than others, but somewhere between 60 and 75C should be OK. I wouldn't let it get higher than 80 as you risk damaging the motor.

[h0m3sy]

Originally Posted by ian h

That sounds very under geared to me. For the 10.5 you should be up around 27 or 28 if it fits with the 83 spur. I would reduce the spur to 76 or 78 and then start off with a 26 pinion and go up from there if temps are ok. Last time I ran a 10.5 I used 78/27 with a speed passion motor. Temps were fine.

Remember though Ian, the young lad is just learning on a small track, he can always change the gearing as his driving gets better. The gearing you are suggesting would be too quick for a begginer in my opinion.

[ian h]

Originally Posted by h0m3sy

Remember though Ian, the young lad is just learning on a small track, he can always change the gearing as his driving gets better. The gearing you are suggesting would be too quick for a begginer in my opinion.

Yes but undergearing can cause the motor to run hot also. Easier to turn down the speed on the transmitter but have it geared right.

[westyguesty]

OK, so start with an 83 / 21 to get him up and running, no risk of thigs getting hot that way, and probably give him more run time. Thsi woud be for a 10.5 motor, so presume for the 13.5 add a few so maybe 83 / 24 and go from there.

[h0m3sy]

Instead of going up on the pinion size, just use a smaller spur. The rule I always go by with the Cougar is the total tooth sum i.e spur +pinion should not exceed 104. Some guys may disagree, but it has worked for me.

[TonyV2382]

This site has always been a pretty helpful guide for me http://www.rcgearhead.com/Gearing/Browse ...I run 13.5 boosted and liked 76/28 and I have also played with 81 tooth spurs as well...As long as your temps arent in the danger zone you will be fine, run it for around 5 minutes or so, pull it off and temp it....go by feel, make sure your car doesnt top out too early or too late on the straight without sacrificing performance in the twisties. with some experimenting you will find the sweet spot quick.

[westyguesty]

Great app, thanks. Gives me an idea if a few pinions to get and try.