Changing tire size for better powerband? - Honda Prelude Forum

Satan_SRV · 07-17-2003, 11:38 PM

So I have an Accord Euro-R tranny on my H22a...I did a couple test runs and did 14.5@99 or so, I had major traction issues and basically spun through 1st and 2nd, slicks are now required that's for sure.

But what I really noticed is that I'm at a really weird spot when I finish....I'm maybe only at 6500 rpms in 4th gear....the euro-r tranny is really short geared through 2 and 3, leaving 4th kinda long. My theoretical top speeds in each gear right now are

1 - 42
2 - 64
3 - 90
4 - 124

@ 99mph I'm only at like 6350rpms....my peak power is at 7200...

Am correct in assuming you want to finish the quarter at or just after you hit your peak power? Makes sense to me, just cause you're not wasting...so I was going to buy some tires and I had an idea....If I bought 215/40/15 tires my over tire diameter would make my theoretical top speeds at

1- 37
2 - 58
3 - 82
4 - 113

at about 101 mph I would be at 7100 rpms ish....that's sounds better.

So is this a good idea or am I totally missing it? The other thing I was thinking was trying to cram a 27 inch slick in there so I would top out at 102mph in 3rd....is that a better idea?

J01SH · 07-18-2003, 07:32 AM

good Questions, i went from my stock wheel and tire 225-50-16 to 205-50-15 Drag radials and my MPH Stayed trhe same 93 ish but i was about 6000 in fourth gear when with my street tires I was just shifting into fourth. The difference in 1/4 mile times was a few tenths but I attribute that to my 60's getting much better with DR's.

Satan_SRV · 07-24-2003, 06:49 AM

Anybody else?

jnkoh · 08-03-2003, 05:32 PM

I thought if you went with smaller diameter tires, you are effectively shortening your gear ratio, which increases your acceleration. For drag racing it would be good to go with smaller diameter tires. I know a guy who runs 13 inch rims on a civic hatch with a type R motor swap and ran a 13.8.

PreludeRacer023 · 08-04-2003, 11:05 PM

hey...well ...id guess your biggest problem is traction, its going to be hard to swap tire sizes to gain that much..actually biggier tires are heavier ect..also i dont think you need slick good new radials should do the trick, i cant wait to get mine, i recently ripped off a 2.0 60 on my verrrrrryyyyyy old 225/50 drag radials..there like no tread on them at all...i can easily see 1.9 on new BFGs on my car...im also going from a 225/50 to a 205/45/15 which will shorten my gears, and your tranny is kinda intersting, looks as though its really made for road racing not Acceleration in the 1/4...btw i hit 4th right at the end, i can hold third to 8200 if i want but my times are faster going to fourth, i cant wait till this winter when we get some cool weather...getting my new radials...and my nitrous, hoping to see some 12s possibly well see i guess, good luck with your setup Joel