tire size and drive ratio

If I change from the stock 225-40-18 tires to 225-35-18 would I notice a
significant improvement in the launch? That change would amount to the
speedometer reading 103.7 mph instead of 100 mph, and would multiply any
drive ratio by 1.037 or very close to that. For instance, first gear would
go from, say, 4:00 to 4:15. My hunch is that that would make a big
difference in the launch. Is that correct? Thanks.
Roy

On Sat, 15 Sep 2007 17:57:57 -0500, "Lanning"
<pati_lanningREMO0O0O0O0OVE.RemoveThis@THISbellsouth.net> wrote:

>If I change from the stock 225-40-18 tires to 225-35-18 would I notice a
>significant improvement in the launch? That change would amount to the
>speedometer reading 103.7 mph instead of 100 mph, and would multiply any
>drive ratio by 1.037 or very close to that. For instance, first gear would
>go from, say, 4:00 to 4:15. My hunch is that that would make a big
>difference in the launch. Is that correct? Thanks.
>Roy
>

So you have a tire that is 25.086" tall with the 40 and 24.2 with the
35? Your first gear might be 3.89x3.45. speed at 6,000 rpm might be 33
mph with the 40 and 32 with the 35. My guess is no you will not feel
any difference unless you are easily swayed by hopes. If you are
easily swayed by hope and refuse to use a Vagcom or drag stip to
quantify then you will see 15.3% faster acceleration with the lower
aspect tires. Of course every time you hit a pothole and have to buy a
new wheel and tire then your fast acceleration will be no faster than
the tow truck.

http://www.scirocco.org/gears/