servo_fan

My 97 4Runner SR5 V6 4x4 has 15" wheels and I guess what amounts to 28" tires with 3.909 gears. I know most 4Runners that came with 16" wheels/31" tires have at least 4.10 gears, and those with the locker have 4.30 gears.

My confusion lies in that new gear ratio calculators suggest if I wanted to upsize to 31" tires, (equivilent to what the Runners with 16" wheels have), I'd want to run 4.23, (rounded up to 4.30?) gears.

Now if this is true for me to regain "stock" driving characteristics, why would Toyota originally supply 4.10 gears in rigs with 31" tires? Shouldn't they all have had 4.30 gears?

I'm confused...thanks for any help.

marko3xl3

Check this out, it's a pretty accurate chart for you to compare which gears give you the best power/milage (or a combo of both) on different size tires.

http://www.4lo.com/calc/geartable.htm

What you have right now is the best of both worlds basically.

As you can see, 29" @ 4.10 gears give the truck slightly more power but less fuel ec. I always thought those 29" looked horrible on 4Runners, and always prefered the 31".

Marko

servo_fan

Thanks for the quick reply. I've seen that calculator and all the others, they just use a standard equation to figure the new ratio, but I was confused because if I want to upsize to 31" tires it says I should run lower gears than Toyota supplied from the factory, unless you had the locker with 4.30s. That's the confusing part to me. If I did upsize the tires I probably wouldn't spend the ~$1000 to go from 3.909s to 4.10s, although the calculators all say to run 4.30s.

Gears plus the speedo being off might be more trouble and money than it's worth.

marko3xl3

I didn't even know 4Runners came with 3.9's, I thought all of them came with 4.10's?

As you see by the chart posted above, 4.10's are perfect for 31" wheels. I guess toyota thought that if people wanted the e-locker option, a bit higher of a ratio would be appropriate.

Anyways, I have a 3rd gen (like you) with 31" and 4.10 gears and it runs perfectly, I couldn't ask for anything more.

I don't think that just because you want to switch to bigger tires that you should worry about re-gearing if you have 3.9's, unless you want that extra power. For me it wouldn't be worth the bother, but that's just my opinion.

Why would you like to switch to bigger tires anyways (besides the looks of course )?

servo_fan

Well honestly looks are a big part of it, plus after I got stuck in some icy snow when 4 wheeling in May, I swore that if I had just like and inch more clearance that I wouldn't have had to be pulled out. Silly I know, but thanks for your input.