Kraton Pinion gear. Max 6 hitting temp cut off

[FatCatRC]

What size pinion should I run with a 4985 1650 kv motor. I have the 29 tooth on there right now and the esc and motor get quite hot on 6s before a pack is even done and I'm running on pavement with street tires. It's only 22 degrees out (celcius). Any ideas. I have a few pinions to play with, and can order one of needed. Also anyone know of a fan and mount that will fit on the 4985 lmk

 

[Jimbobjr]

All 4985 fan mounts I have seen are home/custom made. Maybe the new k8s one could be modded or zip tied on some how. It’s made for a 46mm can) I pretty much run on dirt and grass and run a 20-22t pinion depending on the weather. The esc will still thermal but motor stays cool with my home made twin Hobbystar fans. On pavement maybe 23-25t but really don’t have any experience. @Mr.Duke has a lot of experience with that setup and has had some pretty serious speed out of his. Even runs 8s, maybe he could help with a pinion selection.
Edit: this guy might be able to help with a fan mount. https://m.facebook.com/NTFRacingRC/

 

[jkflow]

I'm using the one below but it has to be modified. You have to spread it apart to make it work and had to trim some cooling fins in the front.
I'm in FL (~35C/90F), with 20T on grass the ESC will overheat at ~ 10-15 min, motor at ~ 160F with backflip tires.

Get a temp gun and check your temps to determine what will work for you. 160-170F is as high as I would go on the motor. ESC has thermal protection and you will know.


https://www.amazon.com/gp/product/B00LXCLEXQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[JerryBoor]

You just have to gear down by 2-3 teeth at a time and test it. I would guess that somewhere between 22-25 would be about it.

 

[FatCatRC]

okay computer water cooling parts for the win!! My unused resivior mounts fit perfectly on the 4985 motor and snap in place securely. So now my question is, does anyone know of a good high speed fan at 50mm I don't care if I need to buy a bec for it too.

okay computer water cooling parts for the win!! My unused resivior mounts fit perfectly on the 4985 motor and snap in place securely. So now my question is, does anyone know of a good high speed fan at 50mm I don't care if I need to buy a bec for it too.

 

[Mr7wun8]

Will that setup do well with the heat?

 

[FatCatRC]

Will that setup do well with the heat?

I'm making metal plates that will screw onto those clear plastic pieces going horizontaly across them and attaching them togethor so I can mount 2 40mm fans on the metal plates. That way the whole unit can come off and on as one. I just lucked out and the clips that came with my resivor tube for my computer fit and snap perfectly around the motor. I'm getting two kinds of fans to try, server fans 40mm at 17000 rpm 12v .60amps and an aluminium hobby fan at 40mm 16000 rpm 8.4v .2 amp. I'm gunna see what kind keeps the motor cooler. Both will need a bec but I found one that does both 12 and 8.4 volts and can more than handle the current draw.

 

[Mr.Duke]

20/46 or 22/50 gearing works well both on 6 and 8s with that combo

 

[FatCatRC]

20/46 or 22/50 gearing works well both on 6 and 8s with that combo

Thank you!!

Will that setup do well with the heat?

And I will be replacing the stock esc fan with a higher cfm fan the stock fan is a lil wimpy

 

[FatCatRC]

I have both 50t and 46t spur gears, what do you recomend for the 20t pinion and the 22t pinion. I don't want to buy the wrong one with the wrong pitch or something.

20/46 or 22/50 gearing works well both on 6 and 8s with that combo

I have both 50t and 46t spur gears, what do you recomend for the 20t pinion and the 22t pinion. I don't want to buy the wrong one with the wrong pitch or something.

 

[FatCatRC]

20/46 or 22/50 gearing works well both on 6 and 8s with that combo

Will these work? https://www.ebay.ca/itm/Robinson-Ra...nion-25-Tooth-48-Pitch-5mm-Shaft/202973998335

https://www.ebay.ca/itm/Robinson-Racing-2022-Hard-48P-Machines-22T-Pinion-5MM-Bore/123301618559

 

[jkflow]

No, you need Mod 1 pinions. 5mm as well.

 

[FatCatRC]

No, you need Mod 1 pinions. 5mm as well.

Do you know of a 22t and 25t that will work, too many options on ebay I'm getting confused.

 

[Mr.Duke]

Search TKR4182

 

[FatCatRC]

I found a mod 1 22t and 25t from robinson racing are those any good or do you recommend tekno only?

 

[jkflow]

No experience with robinson racing pinions on my side. Tekno will last forever, I use both Tekno and Aarma ones.
Had some cheapo ones from Amazon (MakerDolt) but they are only good to right-size and experiment. They will disintegrate after ~ 8 runs, utter garbage.

This is the one I use, 24T
https://www.amazon.com/gp/product/B007KN13LK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[chrisexv6]

A general question - how are you guys running such high tooth pinions? We have a max6/4092 1730kv combo (with YR fans) and even just on the 16T pinion temps will get up to 130-ish before a 5000mah pack is done. Its a mix of running in grass (a few laps around the house), a few speed runs on pavement and mostly bashing around in a dirt area with a few small jumps.

Its warm up here in CT, but nothing like you guys in FL, etc.

Actually thinking about changing to a 14T now, just to help the temps. But 20T? I would expect it to be worthless for us after a few minutes. Am I doing something wrong?

 

[jkflow]

@chrisexv6 No you are right on. 24T was on construction site with smooth dirt (Max6/4985 combo), lots of jumping and lots of downtime (ambient ~82F). Had no issues.
20T on grass and motor was at ~160-170F and ESC cut off after ~ 8-10 min (~90F ambient).
Now on 18T and ESC still cuts off after ~12 min. Changed driving style with more cooldown time. Haven't gone out much as this is no fun being out at 95F/70% humidity. Usual down time for me during summer.
Pinion selection advice is hard to give as it depends highly on surface, driving style and ambient conditions. I do run a 30mm turbo fan on my ESC but honestly I haven't seen a difference to the stock fan.