Choosing gear ratio.
 

As it sits right now I have 3:31's but with the upgraded 20's It has fallen some. Judging by the Tire size calculator Im ruunng somehwere around 3:19's or so. I originally wanted 3:55's so with this difference Im gonna go 3:73's and hopeflly my ratio will end up somewhere in the 3:60's.

Any input on this? Im also buying OEM Ford gears and not Ford Racing as they are made by a different company. I can get gears and bearing brand new from dealer for $152.00.

Depends on your goal for the car. strip? autox? road race? roll race? I have 3.31 but with the shorter tires I will be running with my track wheels it ups my gear ratio right where I want it so I will likely not change mine.

Mexico mostly with very little Drag time. 3:19 is extrememly high and i hate it.

then I would go with 3.73 if you plan to keep those wheels

I do for the forseeable future. Car takes awhile to climb the RPM band now. Its noticable.

4.10s!

Jesus Christ!!!

No that's 4.30s. LOL

LOL I think 3:73 is more then enough.

I had 4.10s in my 5spd GT and they were awesome.

If your long term plans include a turbo(s), keep the 3.31s.
Otherwise, 3.73 is a good street, strip, 1/4 choice.

No F/I. Maybe juice later on but mostly motor.

I'm in the same boat as you with 20's and 3.31's and yea....it take a while to climb. I'll be getting 3.73's here in the next month or two. If I get mine done before you I'll let you know how it is.

Just add boost, that will help it climb faster. Lol

That 3650 also had much different gear ratios.

Yep I had 4.10 in my Mach and they were perfect but would be way too much gear in a 5.0 unless all you care about is 1/8th mile race

My car has a 3.15 rear end. Came with the gay 18s with 235/45/18s. I am lowered an inch with 285/35/19s, anyone know how that would effect my gear ratio?

-Alex

Really good tire size calculator at this website. http://www.miata.net/garage/tirecalc.html

Gives you a visual of how the tires are sized differently, and a percentage of how far off your tires are. Yours are only 2%, so not that big of a drifference. You'll actually be going 2% faster than what your speedometer says, but thats such a small difference it will never matter.

Alex, it's probably now around a 3.13-3.14 effective ratio.

Ah thanks guys. I didn't think the change was too drastic. I noticed my speedo hasn't changed at all.

-Alex

Are your new wheels slightly shorter or taller than the old wheels?

If shorter, it's a slightly shorter effective ratio. If taller, it's a slightly taller effective ratio.

Posted this above.

http://www.tacomaworld.com/forum/tirecalc.php

I like this tire calculator cuz it shows pics

Alex , your new wheel and tire combo is 0.53 inches taller

No mine was a T45 :party36:

Missed that. I didn't realize the 18s came with such short tires.

Haha, thanks for second guessing, I had to check again. They were 235/50/18s stock.

-Alex

That's what I was thinking. These cars come with at least 27" wheel/tire combos.

Your rear wheel is now about 1/4" shorter than stock, so your effective ratio when a little shorter to probably a 3.16. Lol

So now I should run 9s all day!

-Alex

This.:mexsmoke:

Oh ya I went from 27.68 on stock 19s to 27.58 with the 20s on a slightly shorter tire. Heck ya I'm running like 3:31.5s now! On a serious note I'm definitely looking at doing 3:73s