Bmax gearing

[Rebelrc]

Are bmax'es limited on gearing due to the motor plate?
just looking at mine and there doesnt seem alot of scope for any more than a 20 tooth pinion
cheers

[rc_penguin]

got a 24 tooth on mates one seems plenty of room for a bigger one

[pb1]

What spur are you running. On the champ pack you can use a 81 tooth or a 87tooth

81= up to 25 i think
87= up to 22 or 23 ???

[Rebelrc]

Which ever comes with the cheap kit must be an 87?

[Yardeeee]

The standard car comes with an 87T spur gear, the 81T supplied with the champ pack is an option part, but I personally just run with the 87 fitted.

The 87 spur gear accomodates 17-20t pinions, the 81 will allow you to go a bit higher, 21-25t pinion.

However, I run mine with a 5.5 motor geared on 21/87, achieved with a slight modification to the motor mount- this is done by taking the cam (the piece of the motor mount which mounts onto the motor), which tapers down towards the lower bolt hole- If you thin down that taper a little more, you can then get a 21t pinion to mesh.

Tom

PS We've also found that the new blue aluminium motor mount from Yokomo does allow you to run a 21t pinion with an 87 spur without any modification.

[gazhillAE]

Spot on Tom!!!

To add to that, ive not modified my motor mount at all and can run 5.5T with 21/87. You have to be careful how you mesh it obviously but all you need to do is put down on a flat surface and make sure you hold the motor in the furthest position away from the spur and tighten the screws down.

Works fine and the mesh may seem to only have a tiny gap but its enough and has worked fine for me.

I tried the 81t spur few weeks ago as a trial...........jesus loads of top end way to much but at Southport i found it was picking up way to late on the straight with nothing really out of the corners either...no punch etc.

It takes the drivability and fun out of the car and makes you want to push it more to get the power out of it. On top of this it was running very warm!!!

Still runs quite warm with the 21/87 and 5.5t but no termo cut off even in 30degree heat few weeks ago.

Very good car indeed but a B44 still seems better!

[Rebelrc]

That exactly what i was going to do many thanks Tom i thought i was going mad .......a car that maxes out at 20tooth...strange
keep up the good work Tom (good sponser) Yardy

[gazhillAE]

If it helps there is a 84T spur available for the Bmax to.

Going to try one next weekend and see what i think.

I think the 81T has not enough punch and too much top end and the 87T the opposite.

So having something inbetween should work well

[fastinfastout]

are there any other manufacturers spurs that fit as well?

ie. Associated, kyosho?

[Rebelrc]

The pads look the same as an associated so i will give the b4 84 tooth a try
cheers