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Lunch box gear mesh too tight?

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Hello, I'm building my first Lunch box / Midnight pumpkin and am a little stuck on assembling the gearbox. It seems like the fixed gear mesh between the pinion and the other gear is too tight. With the motor and everything installed, it's very difficult to spin by hand. Without the motor, the gearbox is very smooth. The motor on its own also spins fairly smoothly. It's only when I install the motor that the gearbox seems to tighten up.

Is this normal? Will the gears wear in? I'm used to the WR02 chassis which has a butter smooth gearbox. In comparison the lunch box is way too tight.

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Remember that when you turn the wheels the gearing massively multiplies the rate at which the pinion will be forced to spin. As the motor provides resistance it's much harder to spin with a motor than without a motor - even if the motor by itself is quite easy to spin or the pinion is freely moving.

I had a similar car that I thought for ages there was something wrong, but it was just a lower turn motor and higher gearing that I'm used too.

However if it really feels stuck, I'll leave it to some experts on the gearbox.

 



 

 

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have you left a small gap between the pinion and the motor? if the pinion is crammed up against the motor, it will be stiff.

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I would agree with what Nikko wrote. If you connect a new 1.5v AA battery across the motor wires and the wheels turn (off the ground), then you're almost certainly good to go.

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Make sure the motor mounts screws are not overtightened too . The motor can be off centre if tightened too much on one side

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Thanks for the replies. I think it may just be Nikko85 said and that I'm not used to a gearbox geared so low. I'll have to give it a run and see if the motor seems to overheat.

 

 

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The gearbox should be okay - they are good and tough. I'd be concerned about controlling it though. Assuming that the ESC and battery are up to the task, a 4.5t Bluebottle is going to be ballistic! The stock suspension is going to have its work cut out for it putting all that power down...

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Tbh, with that kind of grunt, you'd probably be able to do away with the stock pinion and plastic spacer and fit an 08mod (32dp) 18t steel pinion (if I remember right?)

Taping the inside of the tyres maybe a shout, to help stop them ballooning, make it a bit more controllable, as you head towards motorway speeds.....😏

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