Gearing a brushless XV01

[Julezy 0]

Hi everyone,

 

This is my first post so please be gentle!

I'm building the XV01 and I've bought an 8.5T Tamiya/LRP motor and LRP ESC.

I'm a real newbie so I have no idea what I've got myself into as far as gearing, and a whole lot of hurt (according to the hobby guy who doesn't want to know me).

Can anybody please help me with the number of pinion, spur, and any other advice you're prepared to give time sharing, when it comes to this set up.

I have bought a front one way unit, and about to order the slipper clutch and a few other things that I don't really understand to be honest, but they appear to be upgrades!

I also rapidly ordered some 70mm shocks, without being sure whether that will suit the model or not.

So if you're not totally disgusted with my lack of knowledge while impulse buying on eBay, I'd appreciate any help turning it into a mean rally car that will make me and the mates laugh even if it is over powered.

Thanks for reading :)

[Big Jon 684]

With a motor that hot, I'd aim for about a 9:1 FDR for rally use. The slipper is a great plan with that much horsepower. Pay attention to heat! 

All brushless motors have a "sweet spot", and different brands can vary wildly. One might be a dog at 6:1 and a monster at 4:1; the same wind from a different manufacturer might melt down at 4:1 and be a rocket at 5:1, and run ok at 6:1. 

Rally cars are really interesting to get set up. Everything is a compromise because of the varying surfaces we run on, and every driver has different preferences.

[Julezy 0]

On 6/29/2020 at 12:29 PM, Big Jon said:

With a motor that hot, I'd aim for about a 9:1 FDR for rally use. The slipper is a great plan with that much horsepower. Pay attention to heat! 

All brushless motors have a "sweet spot", and different brands can vary wildly. One might be a dog at 6:1 and a monster at 4:1; the same wind from a different manufacturer might melt down at 4:1 and be a rocket at 5:1, and run ok at 6:1. 

Rally cars are really interesting to get set up. Everything is a compromise because of the varying surfaces we run on, and every driver has different preferences.

Hey Jon,

 

That's some very valuable info for me mate.

Really appreciate you taking the time to get back to me.

I've also ordered some metal diff gears and anything I can see to avoid cooking plastic pieces which will hopefully help in the long run too.

https://www.ebay.com.au/itm/Tamiya-54517-RC-XV01-Front-One-Way-Set-52T/273863058646?hash=item3fc382a4d6:g:HhYAAOSwqrtWpgdc

Do you think getting this front one way be a good option? Or will that not work with the ratio you suggest? TBH I need to do a little homework on how to achieve the 9:1 ratio you suggest, I've never been good with maths.

 

Thanks again.

[Big Jon 684]

No problem! To figure FDR, (spur teeth÷pinion teeth) times internal ratio.

The internal ratio is the ratio of the non-adjustable drivetrain (transmission or pulley ratio). The XV-01 is 2.6 to 1. 

I run a 13.5 with a 28t pinion and a 72t spur in 48 pitch, so:

72÷28=2.57

Multiply that by the internal ratio.

 

2.57 x 2.6=6.68

Nice and moderate for my motor. It's very fast for the driving that I like to do, never has heat issues, and gets long run times.

[Julezy 0]

Man thank you so much. Most of the parts have arrived including the slip clutch etc so I'll just go forward slowly and let you know how I go. Thanks again Jon. I really appreciate your time.