Will the friction drive kit fit a 29incher??

You might need longer rear mounting struts, since the tires would be approximately three inches taller. Longer mounting bracket too, depending on rear frame style.

Since the tires are taller, ya MIGHT have to compensate with a smaller-diameter friction roller.

Other than that, it's easily do-able.

I have seen the longer front support on the friction kits(DAX I think) and the wheel is 3 inches taller yes,but only 1 1/2 inches of that is on the top part above the axle,,,you could add a 2 inch x 1 inch flat steel extention plate to the bottom of the rear support with a bolt abd nut,which is being pulled when engaged to hold the roller to the tire