Mid Motor vs Rear motor

[elvo]

Does anyone know which way the engine spins on a gas truck? (GT2, AD2) I know they have 2 idler gears, but I think they're on the same axle :-(

[elvo]

Not only would the 2 'snap' in the right direction, the motor would 'snap' very, very close to the batteries and CG ===> very low polar moment of inertia ==> extreme snapage!

Originally Posted by DoughtyUK.net

definately, 2 idler gears would be ace. it would get the motor 'snap' in the same direction as the wheel 'snap'

think how much control you would have in the air!

[Chris Doughty]

Originally Posted by elvo

Does anyone know which way the engine spins on a gas truck? (GT2, AD2) I know they have 2 idler gears, but I think they're on the same axle :-(

I think they spin the same way as elec, the last exploded diagram I looked at had the i idlers on the same shaft.

[Chrislong]

Would having two idler gears have the same result as having no idle gears??? Less weight!

[Chris Doughty]

Originally Posted by Chrislong

Would having two idler gears have the same result as having no idle gears??? Less weight!

yes, its the differance between an even number of gears and an odd number of gears.

but with just 2 gears (no idler) it would be pretty hard to get the right internal ratio and get the motor to meet with the spur.

[jimmy]

I think the idler is a bit bigger than the layshaft gear, so no. But either way the spur would then hit the outdrive I think!?

[elvo]

Yep. No idler gear is impossible. Many have tried. Many have come to the same conclusion :-)

[OldTimer]

There is no idler gear in the slim2

[Chrislong]

Im sure it could be done, no idler gear I mean. but would have to have whole new gearbox moulded.

EG. If a stock diff gear is 30teeth and layshaft is 15, that 2.0:1.
These won't meet up with no idler gear as spur would hit outdrives, motor into diff etc.

But if the diff gear was 40teeth and layshaft 20, or 60teeth and layshaft 30, that would still be 2.0:1 and create clearance, more flywheel effect perhaps, less bearings, less friction???

Chris

[DCM]

It also raises your outdrives too far too, you can always go like they had on the Top Cat/Couver/Cougar II and have a belt drive rear box, this would allow you to have a low outdrive height but sufficient clearance for the spur gear.

[Northy]

Does the idler gear effect the ratio at all? How do you work out the ratio of the box?

Belt drive is ace though!

G

[elvo]

Originally Posted by Chrislong

if the diff gear was 40teeth and layshaft 20, or 60teeth and layshaft 30, that would still be 2.0:1 and create clearance, more flywheel effect perhaps, less bearings, less friction???

...and a 'XXX4 syndrome' :-D

Idler has no effect whatsoever on ratio. It cancels out. Internal ratio = diff/top gear.

[Northy]

Thought I remembered that from Physics!

Whats the XXX4 syndrome? Being pants?

G

[elvo]

Having the outdrives way too high.

[Northy]

Ah, ok. What does that do then?

G

[DCM]

for starters, you will have to have longer than needed driveshafts, so that means deeper outdrive too, as the suspension compresses, it will push further in to the diff outdrive, plus there are handling implications too, but not sure as to what.

[jimmy]

The more it moves in - the more friction there will be under power / braking so the suspension will bind up and not work as well.
maybe! haha

[Northy]

'maybe', lmfao!

[jimmy]

That was my "I dont know what the hell I'm talking about", disclaimer!

[elvo]

Originally Posted by Northy

Ah, ok. What does that do then?

G

IT SUCKS!

The XXX4 is basically a sled with wheels.

There's what Jimmy and DCM said. That sucks. Then there's the fact that you can't have your 'dogbones level' and have any ride height left. You can't even have the roll center anywhere near where it should be if you want any sort of decent ride height. So in any case: it sucks.