A bit disappointed with speed and handling of TT-02R

[Beena 253]

I recently bought a TT-02R and decided to go with a brushless setup rather than the standard brushed can that I have used in my previous models.  As I am a newbie I went with a 13.5T SkyRC Toro TS50 ESC/Motor Combo, as it says it is designed for beginners and it was reasonably priced (I have no idea of the Kv rating of it though as it doesn’t say anywhere what it is….which means it’s probably really low I guess).

I popped it in the newly built TT-02R and two things became immediately apparent.

1. It isn’t much faster than my TT-02BR with a Super Stock BZ can in it.
2. It handles like a bag of poo.  

I can barely keep it in a straight line - it handles like it’s on ice.  I have to feed the power in really slowly to get it up to top speed and even then it’s all over the place.  I’m really hoping it’s the Tamiya slick tyres that it came with and that the rally tread ones I have ordered will give me more traction.

The speed is also somewhat disappointing and I don’t know if I was expecting too much from it.  I bought a GPS module and tested it out today and it recorded my TT-02BR with the BZ can maxing out at 21MPH and the TT-02R with the brushless can and high speed gears set on (27T pinion and 64T spur) only hitting 23MPH.  

These are both on NIMh and I appreciate that LiPO would be quicker, but I thought that both cans would break the 25MPH mark at least.  Was I expecting too much and is this about right, or have I done something wrong with the build?

Any tips on getting the TT-02R to handle better would be most appreciated.  Like I said - I’m hoping it is the tyres, because I’ve tried it out on two surfaces now and it’s just no fun really.

[Twinfan 2706]

It looks like you're running an FDR of 6.16? 

 

If so, the 2590KV might be OK to run the 5.74:1 ratio with a 29T pinion.  This should give you a little more speed?  Other than that you're looking at tyres, foam inserts, wheel/tyre glue etc.

[alvinlwh 8244]

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[alvinlwh 8244]

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[Beena 253]

6 minutes ago, Twinfan said:

It looks like you're running an FDR of 6.16? 

 

If so, the 2590KV might be OK to run the 5.74:1 ratio with a 29T pinion.  This should give you a little more speed?  Other than that you're looking at tyres, foam inserts, wheel/tyre glue etc.

Yes that’s correct - 6.16:1

The tyres I have have foam inserts and are glued.  They are just like driving on blocks of ice.  I’ll see if the rally tyres are any better when they arrive tomorrow.

12 minutes ago, alvinlwh said:

A 13.5T is around 2800kv, give or take 200 either way. IIRC, yours is a bluebottle right? When I tested that with the SkyRC card and TS50 (same setup as yours), it reported the KV of that motor at around 2650kv.

According to my calculator, the speed you got is correct, unfortunately.

I too tried out BL and hit the same disappointment wall as you. Part of the problem is the TT gearing, a 13.5 can be geared to 4.8, but yours is only 6.16. If you use a 29T (FDR 5.74) pinion, you should get 2mph more, the motor can handle that ratio. You cannot go further without modification though. With "perfect" gearing, you should get about 30mph, on paper.

Another thing about brushless is there are timing, turbo, boost and angle settings to consider, enough to make your head spin. BL, unfortunately, is not a slap it in and go thing. Since I don't race, I mostly just use brushed instead. Most of the advantages of BL is lost on me, with the serious disadvantage of being very expensive.

Ok so that is about where it should be then.  That is disappointing.  I was hoping to hit 30mph at some point so I guess I’ll have to get a bigger pinion and have a rethink.  

When you say you can’t get any further without modification - what would that entail?

[Tamiyastef 3215]

Is there any room left in programming the ESC? I started my brushless life with e cheap (then € 60,00) Carson brushless set. The timing of the motor can be set from 0° to 26,25° on the ESC. Next to other settings there's also the "Start Mode" or punch that can be changed from level 1 (soft) to level 9 (very aggresive). I found playing with these made big differences in the end speed as well in the acceleration of the car. It is a 3600kv motor though. Another reason may be the Nimh can't discharge rapid enough to get the max out of the motor... I noticed a big difference when I changed from a Traxxas 8,4V Nimh to (much lighter) 7,4V Lipo. The car was quicker, more responding and more fun to drive (IMO) with the Lipo.

[ChrisRx718 4894]

Also, a TS50 is pretty low amperage. I know it says it has a current burst of 300A, but a continuous 50A ESC is never going to feel particularly quick. In order to run a Super Stock motor you already need an ESC capable of pulling more amps than that. In my (limited) experience, it's the current pull which really makes a setup 'feel' fast. LiPo power is another advantage, again because the power delivery is much more 'punchy'. 

The RPM of the Super Stock BZ (at no load) is some 26,500 @ 7.2v.
To work out the max RPM of a brushless motor, as @alvinlwh points out, multiply the Kv by the voltage - ie. 2650 x 7.2 NiMh = 19,000 

If anything, it should feel slower than your previous setup. 

I know there is a lot of reluctance due to the risk factor, but treated correctly the singe biggest upgrade you can make to both power and run time is to go LiPo 2S. 

[alvinlwh 8244]

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[Beena 253]

4 minutes ago, Tamiyastef said:

Is there any room left in programming the ESC? I started my brushless life with e cheap (then € 60,00) Carson brushless set. The timing of the motor can be set from 0° to 26,25° on the ESC. Next to other settings there's also the "Start Mode" or punch that can be changed from level 1 (soft) to level 9 (very aggresive). I found playing with these made big differences in the end speed as well in the acceleration of the car. It is a 3600kv motor though. Another reason may be the Nimh can't discharge rapid enough to get the max out of the motor... I noticed a big difference when I changed from a Traxxas 8,4V Nimh to (much lighter) 7,4V Lipo. The car was quicker, more responding and more fun to drive (IMO) with the Lipo.

There may be and I have a SkyRC Program Box on its way to me to enable me to do that.  I didn’t realise that I had to buy one of those just to get the thing to go in reverse! Seems stupid to only have forward and brake as the default out of the box.  I’m not ready to go down the LiPO route just yet and want to maximise what I can get from NIMh (plus my wife doesn’t want them in the house).

3 minutes ago, ChrisRx718 said:

Also, a TS50 is pretty low amperage. I know it says it has a current burst of 300A, but a continuous 50A ESC is never going to feel particularly quick. In order to run a Super Stock motor you already need an ESC capable of pulling more amps than that. In my (limited) experience, it's the current pull which really makes a setup 'feel' fast. LiPo power is another advantage, again because the power delivery is much more 'punchy'. 

The RPM of the Super Stock BZ (at no load) is some 26,500 @ 7.2v.
To work out the max RPM of a brushless motor, as @alvinlwh points out, multiply the Kv by the voltage - ie. 2650 x 7.2 NiMh = 19,000 

If anything, it should feel slower than your previous setup. 

I know there is a lot of reluctance due to the risk factor, but treated correctly the singe biggest upgrade you can make to both power and run time is to go LiPo 2S. 

I’m running a Hobbywing QUICRUN 1060 ESC for the Super Stock motor - would that be sufficient?

Your calculations of the BL motor being slower would make sense, as the Super Stock is in my buggy, which has an FDR of 10.71:1 and yet is only 1mph slower than the TT-02R with the high speed gearing.  I’m going to swap them over and see what the top speed on the TT-02R is with the BZ in it.  I would hope that would get it up to around 25mph?  I was hoping for around 26/27mph originally and my first milestone is to hit 30mph, with a goal of getting to 40mph eventually. 

I may well go down the LiPO route at some point but for now I’m sticking with NIMh to appease my wife and challenge myself to try and hit 40mph on it.

[Andreas W 3311]

Regarding tyres these were suggested when we had a thread about tyres for tarmac this spring. I run them on my XV-01 in Postal racing. No ice feeling on tarmac with norwegian summer temps.

 

https://www.rcmaritimenorway.no/product/ride-ride-slick-tires-belted-on-16-spoke-wheel-pre-glued-4/

[alvinlwh 8244]

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[Beena 253]

2 minutes ago, Andreas W said:

Regarding tyres these were suggested when we had a thread about tyres for tarmac this spring. I run them on my XV-01 in Postal racing. No ice feeling on tarmac with norwegian summer .

 

https://www.rcmaritimenorway.no/product/ride-ride-slick-tires-belted-on-16-spoke-wheel-pre-glued-4/

Thanks I’ll have a look into those.

 

1 minute ago, alvinlwh said:

The TS50 is very programmable, probably too much for a beginner. Also, a card (and preferably PC) is needed.

I am fully prepared to be baffled when the program box arrives tomorrow 🤣

[Beena 253]

5 minutes ago, alvinlwh said:

You can go beyond 29T if you cut up the gear cover, so so that is what I had seen. Someone who had tried it will be able to advise you further on it. A 34T pinion will give you FDR 4.89 and 30mph.

You do need BL to do that, just a chassis that allow free and crazy gearing. I got 40mph out of a silver can (it didn't last very long though).

Thank you ever so much for your help.  It’s all very daunting as a beginner and this kind of info is really appreciated. 

It would seem that my motor is pretty underpowered then for what I ultimately want to achieve.  Do you have any recommendations for a motor and ESC that aren’t crazy expensive and would allow me to hit higher speeds (bearing in mind my ultimate goal is also 40mph)?

I’ll have to get the Drexel out on that gear cover it would seem and find a larger spur gear and pinion.

[alvinlwh 8244]

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[Beena 253]

13 minutes ago, alvinlwh said:

Before you start posting questions, I already did that. 😁 And I am still none the wiser!

 

 

Thanks for that link.  I think I am slightly less baffled, but still pretty clueless 🤣

[alvinlwh 8244]

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[Beena 253]

3 minutes ago, alvinlwh said:

You replied before I got a chance to edit my original post, which some bits don't make sense.

There are still Speed Passion 4.5T motors going for <£20. However you will need to pair it with at least a 120A, 160A preferably, ESC. I got a Hobbywing 10BL120 to go with it, about £40?

You have to be careful about gearing that one (checking my notes...) to FDR 8 - 10. So looking on the TT-02 speed gear chart, 22T + 68T.

Popping all the numbers into my calculator...

56mph, or a speeding ticket if driven in town. Note that these are all "in theory" as you will need a high C battery to run that motor. I suspect your NiMH will blow if you try to connect them to it!

Ok….so my options are reduce my FDR with a less powerful motor to get higher speeds or increase the power of the motor.  That calculator you have is very useful.  I’m guessing that is an Android app and not iOS?

If I wanted to stick with NIMh, what considerations do I need to make in terms of battery power when it comes to choosing a motor and ESC? You said I’d need a higher C battery - what does that mean exactly?

[bRIBEGuy 3426]

I've generally had pretty poor results with Tamiya road tires as far as traction with any amount of power.  Can be fun with a mild brushless setup like yours if you want to rally/drift/hoon around... but it gets old quick if you actually want to drive (or go fast without the risk of sliding into a curb).  The stock "treaded" tires in my TC01 kit feel about as "on ice" as what you have described.

For better grip/handling: Try better tires.

For more speed, you're likely looking at going LiPo, and to a faster motor (and or ESC).  Brushless is more efficient than brushed, but not necessarily faster.  A 13.5t motor is pretty mild (as you have discovered).

[bRIBEGuy 3426]

12 minutes ago, Beena said:

Ok….so my options are reduce my FDR with a less powerful motor to get higher speeds or increase the power of the motor.  That calculator you have is very useful.  I’m guessing that is an Android app and not iOS?

If I wanted to stick with NIMh, what considerations do I need to make in terms of battery power when it comes to choosing a motor and ESC? You said I’d need a higher C battery - what does that mean exactly?

The "C" rating of a battery is it's ability to charge/discharge power at a given rate.  A 5000mah pack with a 20C pack can safely put out 100amps peak.  A 40C pack would double that.  Most NiMh packs don't even list a C-rating for discharge, as it is comparatively VERY low compared to LiPo (typically under 10C).

[alvinlwh 8244]

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[alvinlwh 8244]

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[Beena 253]

5 minutes ago, bRIBEGuy said:

I've generally had pretty poor results with Tamiya road tires as far as traction with any amount of power.  Can be fun with a mild brushless setup like yours if you want to rally/drift/hoon around... but it gets old quick if you actually want to drive (or go fast without the risk of sliding into a curb).  The stock "treaded" tires in my TC01 kit feel about as "on ice" as what you have described.

For better grip/handling: Try better tires.

For more speed, you're likely looking at going LiPo, and to a faster motor (and or ESC).  Brushless is more efficient than brushed, but not necessarily faster.  A 13.5t motor is pretty mild (as you have discovered).

I’ve ordered some Fastrax rally block tyres that will hopefully solve the handling problem.  The slicks that came with it are next to useless - even after warming them up.

Yes I didn’t realise that the 13.5T was so mild.  I mistakenly thought that it would be a lot more powerful than my BZ can because that’s a 23T.  I have a lot to learn!

[bRIBEGuy 3426]

1 minute ago, alvinlwh said:

From the information I can find, NiMH produce 1 - 2C. Race packs can produce up to 10C. Not sure how accurate the info is though.

Yup, that sounds about right.  Plus they have a much steeper discharge curve, so you're really only getting "full power" for a brief period at the beginning of a run.

Swapping a decent quality NiMh pack (3700mah) with a crappy 20c 3300Lipo in the same car is a NIGHT AND DAY difference when I've done it.  Using a better LiPo makes that even more apparent.

 

Just now, Beena said:

Yes I didn’t realise that the 13.5T was so mild.  I mistakenly thought that it would be a lot more powerful than my BZ can because that’s a 23T.  I have a lot to learn!

Part of the hobby is learning.  And part of learning is making mistakes!  Any of us who claim to have never goofed up are clearly lying!

[Sogogi 3364]

Maybe go for like 3.5t / 4.5t BL motors…. (Will require much beefier esc too)

[alvinlwh 8244]

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