Hobbywing QuicRun 10.5 T Combo Really Slow So Frustrated (Correction, it Literally Flies!)

[Snaab9-2]

If you're concerned about overheating, putting larger diameter tires on AND going with a bigger pinion gear will increase the chances of overheating...just saying. You're already pulling wheelies, so try reducing the punch a notch or two, and lessen the drag brake setting. I wouldn't mess around with timing until everything else was running pretty much the way I liked.

Yeah, I am going to turn the punch down for sure. I might try 5 next tine out. I am not worried about it overheating at this point, I was trying to say that I felt I could run taller gearing and be OK (on road is all I am doing right now). You think I should try a different pinion before trying to adjust the timing?

[Snaab9-2]

I'd be careful with the gearing. For off-road applications, that esc only looks to be rated down to 13.5 turns.

I might end up putting the ESC in my Big Brute or Turbo Raider at some point as I didn't fully appreciate it isn't the most robust ESC but so far it seems adequate for what I am doing. It was about 60 out today so on a hotter day I will have to keep a closer eye on things. The little fan on the ESC seemed to help keep things cool even when I ran it non stop as hard as I could for about 5 min straight.

[RC10th]

Find a buggy that lists a recommended FDR for 10.5T and calculate the gear radio backwards. You can use any buggy, doesn't matter.

Spur ÷ pinion x transmission ratio = FDR


Use this as your starting gear ratio.

[Snaab9-2]

Find a buggy that lists a recommended FDR for 10.5T and calculate the gear radio backwards. You can use any buggy, doesn't matter.

Spur ÷ pinion x transmission ratio = FDR


Use this as your starting gear ratio.

So I come up with 11.4:1 if I have a 76 tooth spur, 22 tooth pinion and a 3.3:1 trans ratio.

Maybe I will try a 31 tooth pinion to get close to 8.0:1

[RC10th]

The RC10 says 8.68:1with 10.5

So.....

If that's the case I would start with a 28 or 29 tooth pinion

76 ÷ 28 × 3.3 = 8.96 FDR
76 ÷ 29 × 3.3 = 8.65 FDR

[Snaab9-2]

The RC10 says 8.68:1with 10.5

So.....

If that's the case I would start with a 28 or 29 tooth pinion

76 ÷ 28 × 3.3 = 8.96 FDR
76 ÷ 29 × 3.3 = 8.65 FDR

I already picked up a 31 when I was near a hobby store but if it is too much I will try a 28 or 29! Thanks!

[RC10th]

The 31 may be too much but you can at least try it to see how it compares, just beware of heat or cogging as that's a sign of being over geared.

[Snaab9-2]

The 31 may be too much but you can at least try it to see how it compares, just beware of heat or cogging as that's a sign of being over geared.

Sorry guys, I am making all kinds of mistakes here. So I was working on the car before work this morning and I seem to have confuse the spur gear teeth with my son's Bandit. Mine has somewhere around 63 teeth (I may have been off a tooth or two but couldn't be bothered to count them again).... so yeah, a 31tooth pinion would be really tall gearing. I really want to get the car running and I remembered my son's bandit just happened to come with an optional 28 tooth pinion. While the gearing will be pretty tall, I am going to give it a try tomorrow morning.

It turns out the I could not quite fit the 31 tooth pinion in the Ultima (well it just fit but there wasn't enough adjustment to get the proper mesh). The 28 tooth fit perfect! You might be able to fit a 29.... but I don't think any more. I was thinking about getting the Dremel out and making the motor slider adjustment area a little longer so the 31 would fit.... but that is before I realized the spur gear was smaller that 76 teeth! My FDR will be 7.4 but I am only running it on pavement like this and the 22 tooth seemed too darn short so it may end up being just right.

Wish me luck! I am going to turn the punch down to 4 or 5, put the braking down to 25%, and try that for now. I may add some timing the run after that if things stay cool.... we shall see. And that 31 tooth can still be used in the bandit for high speed runs!

[terry.sc]

Does the esc have timing function?

Yes it does. By default it is set to 0. I have not tried to adjust the timing as I figured even at 0 it should be pretty darn quick.

This will be your problem, there's a reason the ESC comes with the default timing set at 15 degrees. 0 degrees timing is only really used for crawling, where you need the maximum amount of low speed torque and top speed is irrelevant. Zero timing will kill your top speed and give you tons of low end torque which is why it reaches top speed quickly and the wheels lock up when you are braking. I use 10.5T motors for vintage racing, and looking at the base settings I use for them I start with about 25 degrees timing to start with, then using boost and turbo timing in a race ESC it's using about 40 degrees of advance timing down the straights.

For gearing with a 10.5T I usually start around 8:1 and adjust from there, going for a smaller pinion if it's getting too hot.

That being said, even they the motor is called a 10.5T I think that is misleading. It is only 3600 kv. They sell another motor that is 10.5 T that is 4,000 KV (I almost got it but was worried it was too hot).

With sensored systems the number of turns is the actual physical number of turns of wire around each pole, just like brushed motors are described. The kv numbers that sensorless motors use is more misleading as it isn't a fixed number and is only measured on an unloaded motor so doesn't take into account the torque of the motor so no comparison of how it will work when in use.

With a 10.5T motor there are 10 and a half turns of wire around each pole of the motor. The thickness of the wire used, magnet strength and built in timing all effect what the kv of the motor will be. A more expensive sensored motor will have adjustable endbell timing as well, so while a 10.5T race motor might have a 3200kv rating at zero timing, when you adjust the timing on the motor it could end up with 4500-5000kv. Throw in timing advance in the ESC and it could end up acting like a 7-8000kv motor when at full speed.

The 3600kv motor you have is built for general use, it will have more torque so less current draw and a wider range of gearcratios it will be comfortable with, so it can be abused a bit more. The 4000kv motor is designed for spec class racing, so designed for maximum speed first. It will rev higher, but has less torque, higher current draw, and you will need to get your gearing right or you can cook the motor.

[KidAgain]

May I suggest the HobbyWing BL120 esc for $54.00, I have 4 of these and they are a great enrty level powerful esc's. Ive been over 60mph in RC drag racing 132' with them, bashed with them and run between a 3.5-10.5 motors without issues. Just buy the correct programmer for the $11.00 and have fun.......................

[Snaab9-2]

May I suggest the HobbyWing BL120 esc for $54.00, I have 4 of these and they are a great enrty level powerful esc's. Ive been over 60mph in RC drag racing 132' with them, bashed with them and run between a 3.5-10.5 motors without issues. Just buy the correct programmer for the $11.00 and have fun.......................

That probably would have been a better option..... if I look to get another brushless setup maybe I will get that ESC.... IDK. WIsh I would have before but I think my 60 amp one might be just enough. I am kind of torn as even at punch level 1, my Ultima does wheelies. I want to get a brushless setup at some point for my Raider but that is WAYYYY too much torque for it (weaker gear box and it is a lighter car). I am thinking as my Raider is limited to a 15 tooth pinion, I may be better off to get one of the cheap sensorless setups out there that is a 380 sized motor in a 540 can, put the punch does low, and get a higher KV motor to get some low torque speed in my Raider (maybe like 4,000 or more KV). I want something that revs high but has low torque.....

[Snaab9-2]

I had to let my Ultima Pro XL sit a week or so as I was so frustrated. I needed to process another long repair on a car that I was not familiar with.

I took it out last week with the 28 tooth pinion and I dialed the timing up to 15 (if I recall correctly) and the thing was fast!!! Easily faster than my son's Bandit on 2s. I turned the punch all the way down to 1 but it was still pulling wheelies if I went to full throttle below about 20 mph or so.... I was awesome (thought I wish I could turn the punch down more).... but my old school radio was glitching like crazy! I should have stopped but I tried to keep it close to me and hope for the best but it gliched really hard a few times and then something let go in the trans....

When I got home I took everything apart and the gears and diff looked good which was a relief. I think what happened is the metal gear in the trans box that has the grub screw that holds it to the shaft loosened up and was spinning on the shaft (I had issues with this gear before). It scored the shaft a bit but with a socked and a mallet I was back to get it apart. I serviced the ball diff while I had things apart (that was the main reason why I waited as I was intimidated but it turned out to be easy!). I just got the gear box back together and I am calling it a night. I put some thread locker on that grub screw and got it nice and tight so hopefully I don't have to worry about that again. Another 30 min of work or so and I should have it back in running shape and I think it is OK! (I was thinking hard about selling it and getting something that is more durable)

Thinking back I think that transmitter has always been kind of glitchy but it got BAD! I guess I may try the crystals or maybe the receiver out of my Raider and its transmitter and see if it is any better. I suppose may be better off getting a modern transmitter but that is a ton more research I have to do to make sure it is compatible with my old school servo.... and the wife is going to lose her mind if I spend anymore on my cars so I need to make an Ebay sale first of some vintage stuff I am selling.

I can't drive it if it is glitching though.... it was a run away and I was able to get it to slow down to about 10 mph before hitting a curb two different times (by turning off the radio).... but the hard glitching is really hard on the car so I can't do that again.... it was upsetting.

So for running on pavement, do you guys think my ball diff is going to let go? IDK, it seems like it was good. Do they tend to hold up better if you have them looser or tighter? I have mine kind of in the middle now but before I took it apart it was pretty tight (not sure if that is good or bad).

Thanks!

[Snaab9-2]

Well, got the first shake down run after servicing the trans... she is a ripper even with the punch on its lowest setting (1 out of 9)!!! The torque of the Hobbywing 60 EZRun setup is almost too much as I can make it any weaker. There is a BIG difference from with the original gearing (22 tooth pinion)! I am running a 28 tooth pinion for now. The darn thing still did a couple of wheelies (even on low traction tires.... see 35 seconds into the 2nd video) which I’m trying to avoid as it’s tearing up my motor guard (I need to get a piece of metal to protect the guard as it is getting nicked up pretty badly). Last time out with the glitches from my vintage Futaba transmitter it stripped the 12 mm hexes in the wheels and the grub screw that holds one of the gears onto the shaft spun so a trans teardown was needed. While I had the trans apart I lubed everything and am now a lot more familiar with the car. The best I could tell the ball diff looked OK.

I had changed the battery this morning hoping to run it earlier as I was so excited to finally try the car after hours of working on it (it is going to rain tomorrow) but had to settle for a small lit lot to get a quick shake down run in the dark (had to take my daughter to the hospital for most of the day after her finger got broken at the park). The lot was a bit small for high speed runs but I made it work for the most part.

https://www.youtube.com/watch?v=IL0RfwBUd-U
https://www.youtube.com/watch?v=HV6HMb4cLWY&t=9s

The new Dumborc transmitter worked so good! No more tranny ripping glitches. Well worth the investment to get this car running right! The motor and ESC were only warm to the touch after nearly 10 min of running.... very happy! Can't wait to run it with my son's Bandit VXL. I think it is quicker than his Bandit (his is 100% stock - no doubt with some different gearing his could be at least as fast and on 3S it would blow mine out of the water).

[R6cowboy]

Nice that you have the setup in your Ultima Pro XL up to par. I'm now thinking to replace the stock Reedy 540-SL4 3300kv motor and SC600-BL sensorless esc with the Hobbywing Quicrun 3650 10.5T motor and 10BL120 sensored esc for my RC10T4.3. Previously I was thinking to go with the EZrun 3652 4000kv motor and EZrun Max10 SCT 120A sensorless esc, but I'd like to try a sensored setup. Yesterday I ran the truck on 3s with the recommended factory 18T pinion, 87T spur gearing running 50/50 on grass and pavement, and that stock Reedy motor got scorching hot. So hot it immediately burned my finger touching it for a split second (don't really care since I was already planning on replacing the stock setup). The run ended after power suddenly quit going to the tires during mid-donut. Haven't checked out exactly what went wrong yet but guessing the pinion screw came lose, happened once before with that same pinion gear. At that point the truck was running pretty hard continuously for 30-40 minutes and the motor felt like it came out of the oven, so I was done anyway. Was pretty surprised the battery (Reedy 3s 4500mah 35C) lasted that long and it wasn't showing any signs of slowing down.

[Snaab9-2]

I have never had a sensorless setup but one think (I think) that makes sensored better is the ability to jack up the timing using the ESC (though I guess you can still do it on the endbell with some sensorless ones?). I had my timing up at 15 degrees and it made a significant difference! I just turned it up to 22.5 degrees but haven't run it yet.

I thought I stripped out the hexes in my taller wheel/tire setup but I didn't.... so when I put them back on the thing just flew!!! It was slightly slower accelerating than my sons bandit (punch at 1) but up top slightly faster (with the smaller tires). With the bigger ones it was decently faster than his. Now with the timing bumped up at bit more, I put it is close to 10 mph faster.... but we shall see (of course if he changed his gearing it would probably be close again and he could run 3S but that would just be too fast IMO). Next time I take it out I am going to try to GPS it... I am guessing 45+ mph.

My 60 amp ESC runs nice and cool as does the motor (I guess because the punch is low and the car is fairly light I guess?) so I am really happy. I will have to report back when I run it on a hot day but I think I will be OK. I really don't need the thing any faster..... it rips compared to what I am used to!

That is crazy you battery lasted that long! I don't think mine would last nearly that long! Please keep me updated as to what you do and how you like it, I am curious! How heavy is that truck?