You're not missing anything, that's exactly what happens. However, the difference is so small that unless you are on a hard pack surface you don't notice it.

I always kept my KQ tires at OEM size for the front and rear, but I rode with several other KQ owners who had switched to the same tire size front and rear. They never had any problems with scrubbing.

 

Ok, I checked the KQ 300 specs. It has a 25 inch tire in the rear, and and a 24 inch tire in the front. This comes out to a 4% difference. Not something I would do, but I see what you are saying.

The difference in the circumference of the Quadrunner tires rear to front is 14%. In other words, for every 600 feet you drive in 4WD the front tire will have to "scrub" 14 revolutions.

 

You're welcome mozzer,

The diff lock is to lock the front differential so that both front wheels spin at the same speed, not to lock the front and rear differentials. Obviously there is no rear diff as the drive shafts come straight out from the engine case. This is a great feature, it saves weight, maintenance, and mechanical losses. There is no transfer case or center differential like you would see with a truck or a Subaru or Honda CRV.

I've never messed with CV joints but I know that a bad boot is the kiss of death for them.

How many KM on your new toy? And, lets see a picture!

 

Thanks for the 4wd lesson.

I think the CVs are probably shot, 3 of the boots are split but I'll try pulling the shafts and see how the joints feel.

It has 13,000 kms, has aluminum back end, a cheap winch.

 

Im trying to find some new tires for a 98 Quadrunner, where is a good site with tires this size?

 

rockymountain.com or motosport.com is good. all orders over $100 you get free shipping.