Sketer The Stig's Sketer adventures

[Manolis]

Overheating??

 

[The Stig]

Overheating??

She is heavy. I have 2 fans on it, 15t pinion, 2 fans and 4s only. Everything runs smooth. Tested it. And it is a kuron 825 instead of the 725. Strange thing is. Opened the jammed centre diff expecting the worse. Nothing is broken. Haven't got a clue why the diff jammed

 

[Horatio]

She is heavy. I have 2 fans on it, 15t pinion, 2 fans and 4s only. Everything runs smooth. Tested it. And it is a kuron 825 instead of the 725. Strange thing is. Opened the jammed centre diff expecting the worse. Nothing is broken. Haven't got a clue why the diff jammed

View attachment 5753

Sounds to me like it's the motor that's seized, rather than the diff. The Kuron 825 is a hot motor. It's tough enough getting it to stay cool on 13t, so I'm not sure how the temps would manage on 15t - on the Kronos at least. 13t/52t is 64mph, so just wondering if 15t might be a big ask?

 

[AngrySection8]

Sounds to me like it's the motor that's seized, rather than the diff. The Kuron 825 is a hot motor. It's tough enough getting it to stay cool on 13t, so I'm not sure how the temps would manage on 15t - on the Kronos at least. 13t/52t is 64mph, so just wondering if 15t might be a big ask?

I'd think a 15 would be okay on the sketer, shorter tire anyway so the rollout would probably be similar to the kronos on a 12t or 13t I'm guessing. What's odd about the 825 is we've all experienced the temps it produces in our corallys but I'm running one in my savage flux off an 8bl150 G2 on a pair of 4s packs in parallel, 13lb truck spinning kagama wheels/tires, geared 20/44 which makes it go 42mph-slightly slower than a stock corally truck, yet I can beat that truck hard for 20 minutes straight and to date the hottest I've seen is 108°f on the motor, 98°f on the esc, no fan on motor either due to no room, not complaining just makes me scratch my head.

 

[CCB-MN]

That is a bit of a head scratcher.

Brushless motors generally work very similarly to one another and there really are only a few things that cause heat. It’s just weird that the 825’s seem to run considerably hotter in certain vehicles. Probably in most cases, the most common heat source is going to be resistance, whether it’s due to mechanical or electrical resistance I don’t know. Mechanical is usually pretty quick to locate, there are usually some tell tale signs. I don’t notice any unusual mechanical resistance in any of my TC cars that isn’t also present in any of my other non TC branded rc’s. Seeing this, I would lean towards electrical resistance but that also opens up an entirely new can or worms. The only 825’s that I currently run are all tied to TC esc’s. This means that, while I’m assuming it’s probably a motor issue, (most likely a sub component that is failing or not working as it should or excess supply voltage that’s leading to magnetic saturation). It’s really tough to know for certain without more testing.

To be fair, I’m running the 825 in my SSTE along with a TC esc, and I'm not seeing the same heat spikes that I get in the Kagama running the same size gearing.

I’ve got a few different motors and esc’s lying around at the moment so if I have a chance I’ll try to pair up the 825 with a few different esc’s and see what I get for temps.

On a side note, I’m running the newer Castle 6S capable Cobra in my Tekno, no fans, less air flow, and it never gets anywhere near what I generate for heat in the Kagama.

Weird.

 

[Koma71]

Interne Uebersetzeng 3.31 ist zu lange !!!!

 

[The Stig]

Yeah, going back 2 14t on my big and heavy girl. Ordered new diff cups for centre diff and 2 new drive shafts for front and back. They where bad 2. If the diff is still running rough i need to replace it for a new Erik van Ravenstein version. The Kuron 825 is send to TC in Belgium. They will have a look at it. No movement it the motor at all.
Will keep you guys posted. Thanks for the help guys

 

[Horatio]

I'd think a 15 would be okay on the sketer, shorter tire anyway so the rollout would probably be similar to the kronos on a 12t or 13t I'm guessing. What's odd about the 825 is we've all experienced the temps it produces in our corallys but I'm running one in my savage flux off an 8bl150 G2 on a pair of 4s packs in parallel, 13lb truck spinning kagama wheels/tires, geared 20/44 which makes it go 42mph-slightly slower than a stock corally truck, yet I can beat that truck hard for 20 minutes straight and to date the hottest I've seen is 108°f on the motor, 98°f on the esc, no fan on motor either due to no room, not complaining just makes me scratch my head.

View attachment 5764

View attachment 5765

I think the lower, easier gearing on the flux makes it easier on the 825, which is a low-wind motor. The Kronos XTR on 13t/52t is good for 60+mph on 6S, so must be drawing a helluva lot more current - thus all of us solving the heat problems with fans, heatsinks etc.

Looks awesome btw!

Yeah, going back 2 14t on my big and heavy girl. Ordered new diff cups for centre diff and 2 new drive shafts for front and back. They where bad 2. If the diff is still running rough i need to replace it for a new Erik van Ravenstein version. The Kuron 825 is send to TC in Belgium. They will have a look at it. No movement it the motor at all.
Will keep you guys posted. Thanks for the help guys

View attachment 5767

Yes - you need to do it!!

 

[AngrySection8]

I think the lower, easier gearing on the flux makes it easier on the 825, which is a low-wind motor. The Kronos XTR on 13t/52t is good for 60+mph on 6S, so must be drawing a helluva lot more current - thus all of us solving the heat problems with fans, heatsinks etc.

Looks awesome btw!


Yes - you need to do it!!

I don't think it has "lower, easier gearing", what I'm saying is the flux does 42 on 4s, per the chart @Koma71 listed the corally does 43 on 4s, pretty close in my eyes and my kronos on 4s/stock gearing running twin fans on the motor typically sits in the mid 130°-140°f range, that's why I scratch my head as to why it runs a solid 30° cooler in one vs the other

 

[AngrySection8]

Yeah, going back 2 14t on my big and heavy girl. Ordered new diff cups for centre diff and 2 new drive shafts for front and back. They where bad 2. If the diff is still running rough i need to replace it for a new Erik van Ravenstein version. The Kuron 825 is send to TC in Belgium. They will have a look at it. No movement it the motor at all.
Will keep you guys posted. Thanks for the help guys

View attachment 5767

For what it's worth I ran your numbers (assuming you're running stock tires or a tire of the same height) through a speed calculator and your current setup put you at 38.7mph, a kronos on a 12/52 gearing was 39.4 so depending on the weight of your rig and the terrain you're running you're probably safe running the 15t, this is where a temp gun is your friend, only way to truly know for sure.

 

[Horatio]

Interne Uebersetzeng 3.31 ist zu lange !!!!
View attachment 5766

13t input / onto 43t crown is 3.307 - it's taller than typical race Truggy gearing which is normally 10t / 46t = 4.600.

Ultimately, no one can really say this Corally internal gearing is too 'long' (high) if people insist on using bigger pinions than the stock suggestions by Corally for the 825.

It's a very 'hot' motor - 2050kv and no slouch on 4S or 6S.

It's a mystery why the 825 should run cooler in a Flux than in a Corally rig. If the rollout works out about the same, perhaps the driveline might be nice and free in the Flux?

 

[The Stig]

Well, the bearing from my Kuron 825 is totally wasted. I send it to corally and they found it. Great service because they can fix it and send it back to me for only 20 euro's. For that price i cant fix it myself (time spend) Again, there customer service is great. Motor is 1 year and 8 months old.

 

[The Stig]

Sketer is back up and running. Went back to 14t pinion, changed the front and rear drive shafts, replaced 2 outdrive cups from centre diff, replaced all the bearings that i could find and changed the centre diff fluid with mixture of 2/3 100k en 1/3 500k. On the picture you see the old cups, drive shafts and old 15t pinion. They where work down.
Hope that will make my heavy girl run a bit colder and less ballooning of the tires. Everything runs smooth again. Next mission: change Asuga cvd (lost 1), same mixture for centre diff and some titanium Erik van Ravenstein steering rack.

 

[The Stig]

Does this centre brace sits normal? seems to be sitting a bit crooked.

 

[shortround9191]

Luckely i got the manual. Gonna have a look what i need. Target 2 order more so i have stuff in stock when something else breaks Had stuff arrived 2day. Including the toolkit wich Comes in handy now. And there i am ordering again

I’m new to the car side of RC broke my Spark lower control arm also but also lower shock mount. I ordered a replacement spare along with a set of the HD short lower shock mounts. Like you I keep manuals for part numbers from it all good to go now. You can also check out TC’s vids on repairs there pretty good showing what to do

 

[The Stig]

Question, Sketer steers a bit rough, how can it be fixed? Changed the pivot balls, steering hubs etc. So when i tighten the screw from the Basherqueen (m2c) carbon steeringdeck (side where servo arm is) the steering is getting harder. If i tighten it all the way, you cant steer at all. So i think the carbon flexes to much. So, of i change it to the alu version, will the flex stop? Part number C-00180-673 I did put some shims under the plate allready. Did not work.

 

[shortround9191]

Question, Sketer steers a bit rough, how can it be fixed? Changed the pivot balls, steering hubs etc. So when i tighten the screw from the Basherqueen (m2c) carbon steeringdeck (side where servo arm is) the steering is getting harder. If i tighten it all the way, you cant steer at all. So i think the carbon flexes to much. So, of i change it to the alu version, will the flex stop? Part number C-00180-673 I did put some shims under the plate allready. Did not work.

Something I noticed on the Spark is the steering rack was rubbing on the front driveshaft input collar. I’m running the TC Swiss 7075. My spare that I may install on the Kagama

 

[The Stig]

Something I noticed on the Spark is the steering rack was rubbing on the front driveshaft input collar. I’m running the TC Swiss 7075. My spare that I may install on the Kagama

View attachment 8746

Thanks but i allready got Erik his steering rack. That is not the problem. I think it is the steering deck but i want to know what the rest is thinking. Replace the carbon one for this? https://corally.com/nl/product/C-00180-673/team-corally-stuurdeck-xtr-aluminium-zwart-1st

 

[shortround9191]

Thanks but i allready got Erik his steering rack. That is not the problem. I think it is the steering deck but i want to know what the rest is thinking. Replace the carbon one for this? https://corally.com/nl/product/C-00180-673/team-corally-stuurdeck-xtr-aluminium-zwart-1st

No worries good luck, I have machined and made many many upgrade parts for the RC air side over the years thousands using my upgrades was just trying to help. I just don’t utube who I am

 

[The Stig]

No worries good luck, I have machined and made many many upgrade parts for the RC air side over the years thousands using my upgrades was just trying to help. I just don’t utube who I am

No problem buddy. All the help is welcome. I just cant figure out what is the problem. Trial and error i guess