graemevw

Brushless lunchbox gearing

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I have ordered a speed passion 13.5 for my lunchbox. Im wondering what pinion to fit.

I have read brushless has more torque so you can gear them up some. The lunchbox currently has a technigold in it with the 10t. I want it faster (top speed). I know stock options are 10t or 18t, is 18t pushing it a bit? Worth trying it and see? I might be able to adapt an adjustable motor mount, not sure yet.

I dont know what the rpm will be for this motor, i am using 2s lipo.

With the technigold in it it doesnt even get warm. I ran it flat out for maybe 40 mins and the motor was almost cold, so i figure even that combo would be good for 13 or 14 tooth pinions, if im right in thinking brushless relyes on gearing to make use of the torque rather than motor rpm then 18t doesnt seem too much of a stretch.

If it is, 16 may be achievable with adjustable motor mounts.

This is my first leap into brushless!

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Just had a quick look at the manual and the final drive ratio on the 10t is 14.9. On the 18t its 8.33. The 13.5 will pull a 6.7 gear in a buggy, so the 18t gearing will be fine for the motor given the bigger wheels, but whether the speed would be a bit much for the truck is another question, but a hornet pinion isn't going to cost much to give it a try. I have the same motor in my comical hornet with the 16.5 gear ratio and its pretty easy to tip over tutning in at speed! 

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14 minutes ago, ThunderDragonCy said:

Just had a quick look at the manual and the final drive ratio on the 10t is 14.9. On the 18t its 8.33. The 13.5 will pull a 6.7 gear in a buggy, so the 18t gearing will be fine for the motor given the bigger wheels, but whether the speed would be a bit much for the truck is another question, but a hornet pinion isn't going to cost much to give it a try. I have the same motor in my comical hornet with the 16.5 gear ratio and its pretty easy to tip over tutning in at speed! 

Thats good news. I dont mind it being too fast. I want it to be somewhat idiotic but not completely unusable. I just thought with the extra torque, keeping the lunchbox 10t pinion would make it only want to backflip.

Thanks

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Jeez, all you guys trying to be the first one to put a Lunchbox in low orbit... poor things... What did Vanessa ever do to you?

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22 minutes ago, markbt73 said:

Jeez, all you guys trying to be the first one to put a Lunchbox in low orbit... poor things... What did Vanessa ever do to you?

Thing is, once you do a few mods, you realise its now too slow. With a few mods they are too capable for a silvercan to be fun. I go to a local ish track thats quite challenging and even with the technigold in it its not that hard to do clean laps and on the back straight it could happily be alot faster. 

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I built up a Lunch Box for a friend with 10.5 brushless motor. Used a Hornet 18t pinion. The thing was mental on 3s, 30mph roll on wheelies no problem whatsoever.

I don't recall ever having the thing flat out for more than a second or two though. It was completely stock bar the ,motor, esc and pinion. Fun times!

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With the 13.5 you have, try the stock 10 tooth gear and see how you like it. Depending on your kv rating it might be just what you want. 

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I'm running mine on a little 3200KV outrunner with 10T gearing and it's pretty well balanced on 2s, it's a good all rounder. With 3s it has a decent boost and is good for more open spaces and I especially like it at the beach. It's definitely a bit more of a handful though and I don't need full throttle as often unless I have loads of space.
 


Traction can be an issue on sand with 3s, the diff makes the wheels spin up alternately with pulls the truck side to side. I'm going to try a diff locker next time.
 

 

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Everyone loves a picture, 13.5 speed passion fitted. Ive put the 18t on it first, see what happens. Put some spikes on the back to try and get some traction. Shimmed the play out the front axles too. Just need to make some shock set up adjustments and tweek the front camber and toe again and its ready for some more track abuse next month 😎2LautM5.jpg

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Just did a quick systems check and it looks like this is going to be a bit nuts 😎

I havent really managed to give it proper full throttle with the wheels off the ground as it ballons one tyre more than the other and feels like its going to shake itself to bits. It still pops wheelies in the kitchen even with the 18t.

This is going to be fun! Luckily i havent glued the rear tyres yet so ill tape the insides first as the tyre foams cant keep the tyres under control. 

Looks like this may need a locked diff afterall, anything that provokes a bit of understeer might be a good thing anyway!

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Looking at the vibration again, the tyres are so out of balance the wheels are bending the gearbox case at anything over 1/2-2/3 throttle. Guess id better try and sort that!

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I tried a 17.5t motor with 18t pinion and it was a bit fast for my liking, and didn't wheelie very well. I switched to a 13.5t with the stock 10t pinion and it is perfect for me. I have the FX10 front conversion, solid rod mod on the rear, tires with foams and glued, AW grease in the diff. Oh, CVA's too.

It works for me. YMMV.

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2 minutes ago, Biz73 said:

I tried a 17.5t motor with 18t pinion and it was a bit fast for my liking, and didn't wheelie very well. I switched to a 13.5t with the stock 10t pinion and it is perfect for me. I have the FX10 front conversion, solid rod mod on the rear, tires with foams and glued, AW grease in the diff. Oh, CVA's too.

It works for me. YMMV.

Your lunchbox sounds exactly the same as mine. Higher top speed and less wheelie is what im after really, ill find out soon enough if ive over done it though. I tend to drive it on track a fair bit and the straight is long. There are also some slow, steep short uphill climbs i dont want to backflip it on all the time. Ill try it with both pinions. I can order an adjustable mount too if need be, gives me pretty much full range then.

Im not sure what rpm the motor will do on 2s so i dont really know what to expect. It seems more controllable than lower turn brushed motors though, smoother. 

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3 minutes ago, graemevw said:

Your lunchbox sounds exactly the same as mine. Higher top speed and less wheelie is what im after really, ill find out soon enough if ive over done it though. I tend to drive it on track a fair bit and the straight is long. There are also some slow, steep short uphill climbs i dont want to backflip it on all the time. Ill try it with both pinions. I can order an adjustable mount too if need be, gives me pretty much full range then.

Im not sure what rpm the motor will do on 2s so i dont really know what to expect. It seems more controllable than lower turn brushed motors though, smoother. 

Depending on the motor mount, it may not let you lower the pinion, despite being sold as such. I could go up with mine no problem, it hits the gearbox when trying to go lower. I could get a 17t pinion on and it  worked, but it wasn't fully meshed with the spur.

If you're running on a track, you probably won't want the stock pinion due to the extra torque and it being a "wheelie" chassis. Mine is still running 6-cell nimh's, so lipo will make it even more prone to standing up on the rear down the straights.

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7 minutes ago, Biz73 said:

Depending on the motor mount, it may not let you lower the pinion, despite being sold as such. I could go up with mine no problem, it hits the gearbox when trying to go lower. I could get a 17t pinion on and it  worked, but it wasn't fully meshed with the spur.

If you're running on a track, you probably won't want the stock pinion due to the extra torque and it being a "wheelie" chassis. Mine is still running 6-cell nimh's, so lipo will make it even more prone to standing up on the rear down the straights.

Thats a very good point. 

Im sure i saw one which came with a motor shaft extension and a thick mount like the original, cant find it now though.

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I'm curious to see how that one is installed. It looks like it extends the motor shaft so you can use a regular pinion, rather than finding long ones like the stock pinion. What I have is similar, but the main disc doesn't have the side cutout like that one, which is why it won't work for smaller pinions. The disc hits the gearbox and can't move closer. I use one on my GrassHornet to run a 21tpinion, and it works great. I didn't try it with the stock motor mount on my Midnight Pumpkin, just direct on the gearbox like the GrassHornet. Here's the one I have.

https://www.ebay.com/itm/Tamiya-Hornet-Adjustable-Motor-Mount-Kit-Gear-Cover-Lunchbox-Grasshopper-16t-22t/303110480944?hash=item4692cae430:g:15oAAOxyVLNSo-FR

 

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