Contour Enthusiasts Group Archives Forums Modifications Duratec Performance can i get a shorter (numericly larger) gear my svt?

Glad you guys mentioned tires, as I've been meaning to post about my recent experience. I acquired a set of used 16" wheels with Yokohama A520 205/50/16. Some of you already know that the proper size for our cars is 205/55/16, so the Yoko's that I have are 3.7% smaller in diameter. This effectively raises the final drive from 4.06 to 4.21. And I will tell you, the difference is quite noticeable.

The first thing I noticed was the increased effects of engine braking while coasting in gear. This really confused me at first - the car was slowing down more quickly when coasting however when accelerating hard it felt faster. The second thing I noticed was that I could use 5th gear in city driving and have it pull smoothly from as low as 1500 RPMs (whereas before the tire change it would lug). And on the highway there is more responsiveness.

The downsides of doing this are as follows. Firstly, your speedo is going to be off (by 3.7%) however this is not that big of a deal IMHO. Just remember that your speedo is reading a couple of MPH higher than your actual speed. Secondly, since the RPMs will be higher for a given speed, highway mileage will probably go down. But, in the city it should stay the same or even improve due to greater use of 5th gear. Lastly, an aesthetic issue - there is going to be more fender gap. This is more of an issue on cars without side skirts. The remedy for this is to get lowering springs and/or install side skirts. Or just not worry about it.

By the way, the Yokos are sticky enough that I can launch @3k RPM without wheelhop and minimal tire spin. Too bad they wear so quickly!