Kraton Safe pinion size for speed runs on standard electronics?

[Warby]

Attn Speed gods,

Got the urge to push my Kraton 6s to its limits. Want to test its top speed for a bit of fun (please don't tell me its top speed, i want to find out myself). I'm running the standard BLX 6s 2050kv electronics, standard spur and GRP 98dia wheels. I have currently fitted a 20t pinion to get roughly 72+km/h but it wasn't a very successful run as kept loosing bluetooth connection with speed tracker and also pinion kept coming loose. At what stage is the pinion size going to be too much for the standard electronics? I don't want to kill it, nor do I want to upgrade the electronics at this stage.

Note: I'm only using this gearing for speed runs on road, not bashing and I do have a temp gun if required. Also the motor has a full heat sink with 2 fans and new bearings fitted.

Your input would be welcomed.

 

[3d-rc.myshopify.com]

25t? watch those temps

 

[jkflow]

With GRP a 25T should work. Careful with 'bashing'. Check your temps every 2-3 min.
With stock tires don't go above 20T, they will blow up quickly.

 

[Warby]

With GRP a 25T should work. Careful with 'bashing'. Check your temps every 2-3 min.
With stock tires don't go above 20T, they will blow up quickly.

yep no bashing, maybe a couple of donuts at the most. Actually I've got some old worn Minokawa's which I was going to try for at least one speed run as I don't really care if they fail.

 

[jkflow]

You will be probably be faster on the Mino's, make sure they are glued.

 

[SrC]

yep no bashing, maybe a couple of donuts at the most. Actually I've got some old worn Minokawa's which I was going to try for at least one speed run as I don't really care if they fail.

And they definitely will fail at some point.
Any speed over 60mph (96.5kph) and you will see unbelted tires balloon like mad. Watch diffing out also. And the rig will become unstable. Been there. I run SR Belted terrain Crushers for those higher speeds. I don't like to ruin my off road tires any more for speed running. ?‍
Hey its all fun anyway pushing the limits. I did this in the mid 60's. GPS'ed. Only wish I had my cam mounted on my Kraton when this happened. It wrecked and skated on its roof for 30 feet. No other damage though, just road rash.

 

[Warby]

And they defintely will fail at some point.

what better time to fail then at high speed

 

[SrC]

Actually I cry when it happens to my Lim. Carnage just costs way more.

 

[FatCatRC]

I got mine up to 106kmh with belted street tires and 29t with a 4985 max6 combo. I could go faster but my front end won't stay down. Gunna rig up a spare center diff with thicker oil but not lock it and see what I can get.

 

[Warby]

I got mine up to 106kmh with belted street tires and 29t with a 4985 max6 combo. I could go faster but my front end won't stay down. Gunna rig up a spare center diff with thicker oil but not lock it and see what I can get.

yeah at the moment i'm just trying to max out the original blx system without destroying it.

 

[Spoc85]

Stock Electronics on the Kraton with Katars is good for speeds above 75mph/120k/hr

 

[Warby]

ordered ??

 

[jondilly1974]

I believe you will want to hear from @LibertyMKiii as he maxed his Kraton out on the stock setup on GRPs. He might remember his gearing.

 

[performula]

Where do you get the GRPs?

 

[jkflow]

GRP:
https://www.hobbyheroes.com/collections/grp-tyres
https://nitrohobbies.com/rc-cars-trucks/tires-wheels/wheels-tire-sets/

 

[performula]

GRP:
https://www.hobbyheroes.com/collections/grp-tyres
https://nitrohobbies.com/rc-cars-trucks/tires-wheels/wheels-tire-sets/

Thank you, 1/5 or 1/8? Compound for 85 degree weather?

 

[jkflow]

No idea what you are trying to accomplish ?‍
GRP 1/5th require special wheel adapters but have a larger diameter. On the 1/5th you can go 24T with a 46T center diff and you get to ~ 72mph.
1/8th are a direct fit but smaller diameter = lower speed. You can't go higher in pinion size due to motor mount limitations. You could try a limitless spool in the center. You can do the math on pinion size

With stock tires and speed pinion (20T) you will get to ~ 68mph. Neither setup is for bashing and you will burn out the motor quickly. Only on road surface, no dirt or grass. Stock tires will blow out quickly above 65mph.


https://www.arrmaforum.com/threads/street-tire-recommendations-needed.19398/

 

[Spoc85]

I initially thought I hit a bird before I realised it was just the foam of the tyre shooting up.

I believe you will want to hear from @LibertyMKiii as he maxed his Kraton out on the stock setup on GRPs. He might remember his gearing.

I think he hit 98 with a spool.

 

[LibertyMKiii]

Because the Kraton has the 4.3 ratio diffs you need a lot of gearing, and I don't think my speeds would have been possible without switching to a spool.
The Limitless 34t spool setup is a direct drop in. You can find them on eBay. Be sure to red loctite the set screw for the outdrive cups on them. I have had several come lose.

It did 94mph with the rear wing and 96 without. I considered it "maxed out", but you can always try different things and see what yours will do. Each motor is a little different. With a Typhon 6s it didn't want to get over 94.5 mph despite its smaller size and better aerodynamics. I wouldn't consider this "Safe" as the ESC will eventually go up in flames as it was never intended for this sort of use.

My 96 mph setup was the following:
37t pinion
34t limitless spool
BLX185 esc
blx2050kv motor
Turnigy panther 6s 5000mAh
GRP 1/8 tires
Nero BLX springs (to help stabilize the car)

 

[Warby]

UPDATE:

Finally got time to speed test the Kraton with 20T pinion and the original large Minokawa tyres.

110 km/h I'm happy with that. Yes I know I'm not breaking any records but as an speed amateur I'm stoked. May have got a little faster but was running out of road with a curb fast approaching.

Had trouble keeping the front end down and it got quite unsettled over 100 km/h. A slightly buckled wheel didn't help. Only damage is a wheel came off wheelie bar and some bark off the body and wing. No overheating issues. Did not blow any tyres either.

Next: the 25t pinion with the GRP 98dia wheels.