Originally Posted by Cpt.America
How would the front two tires spinning at a different rate then the back two tires make the car drive better? and in what track condition?
we sometimes run it on asphalt and carpet, with both foam and rubber tires. it's depends on what else is going on with the setup, but here are some examples...
high grip, when your car is diving over the nose (digging), the smaller front diff will cause added braking bias to the front, off power (assuming no one-way is in use) and will keep the front flatter because you're actually sliding the front tires a bit off-power. on power, the pull of the front axle (which rotates more than the rear) will give more steering. if you tailor your driving to suit a car that requires you to lift early and power through, it's very effective to maintain high corner speed w/o the digging/lifting that is customary of other setups with a lot of steering.
in low grip, the same happens, but the overdriven front end will keep it from spinning out off-power (rather than digging in high grip), and give it more pull on-power.
in both cases you lose some turn-in, but you can throttle off the corner earlier. it's usually a wash, but it's a good thing to tune with if you can't get the car to stay down w/o having a massive push.
any setup that has too planted a rear end (like some foam setups) can benefit from this, since the front tires are making a larger radius turn than the rears (and will therefore bind the car up if they don't rotate faster to make up for the larger arc-length).
in r/c, almost nothing that happens in a straight line matters. it's all in the turns. if you tune for the straights, you'll never get it right.
blah, blah, blah ....
as far as the original question goes, i thought i answered it fairly effectively in my first post. assuming your ratio is 1:1 (and i'd bet that it is), you should begin to look at your suspension for imbalances...