Is there a tool to calculate how taller tires well affect final drive ratio?

[4RunnERD]

I have seen and used a lot of great tire calculators to figure out tire/wheel size deminsions and how the speedometer will be affected. But I am curious as what a 265/65/18 tire size will do to the final drive ratio compared to the stock 265/60/18 size? I have heard people say they definitely notice a difference in acceleration with 275/65/18 (even people with V8's) so curious how much I would notice the smaller increase in size with a V8? Thanks.

 

[4RBob]

4Lo.com :: Final Gear Ratio, Crawl Ratio, Tire Size Calculators

 

[4RunnERD]

Thanks for the link, although for me it is kind of confusing... asking for input of some numbers that I have know clue of.

Maybe I mis-prashed in my original post, perhaps "final drive ratio" isn't the right term, but here is what I trying to gauge...

Right now I believe my stock 4Runner has 373 gears. When I accelerate from a stop at a red light on a paved road I know how these gears with the stock tire size feels in terms on torque and the feel of acceleration.

If I increase to a 265/65/18 how much loss of torque and acceleration will I feel with that small increase and having a V8? What will that tire size essentially be making my gears? For example instead of feeling like I have 373's it will now feel more like my gears are ___ ???? Does this make sense?

 

[chaz]

Gears Needed After Adding Larger Tires How to Change the Gear Ratio With Tire Sizes | eHow.com 4x4 Connection - Gear Ratio / Tire Diameter Chart Gear Ratio Guide for Larger Tires probably wont help but interesting anyway.

 

[4RBob]

For simplicity, use the calc in my link above and plug in 32 for tire size, 3.73 diff ratio, transmission and transfer case ratios of 1, and 50 mph. Calculate. Now replace 32 with 31 tire size, clear out diff ratio field. Calculate.

Answer: 3.61

 

[4RunnERD]

Gears Needed After Adding Larger Tires How to Change the Gear Ratio With Tire Sizes | eHow.com 4x4 Connection - Gear Ratio / Tire Diameter Chart Gear Ratio Guide for Larger Tires probably wont help but interesting anyway.

First link worked great only had to input three thing which I knew the numbers of to get my answer.

For those of you curious if you bump up to 265/65/18 from 265/60/18 instead of maintaining 3.73 gearing you will now have the equivalent of 3.61's and you would need 3.86's to achieve the orignal gearing feel. Of course you would have to round up to the next actual size available.

 

[4RunnERD]

For simplicity, use the calc in my link above and plug in 32 for tire size, 3.73 diff ratio, transmission and transfer case ratios of 1, and 50 mph. Calculate. Now replace 32 with 31 tire size, clear out diff ratio field. Calculate.

Answer: 3.61

Thanks, I appreciate it! I figured it out eventually, wasn't sure what numbers to plug in intially.

 

[4RBob]

Thanks, I appreciate it! I figured it out eventually, wasn't sure what numbers to plug in intially.

The transfer case ratio is always going to be 1 unless you are in 4Lo. The transmission ratio depends on what gear you are in. If you were doing 65+mph, you'd probably want to plug in our OD ratio (I don't know what it is off the top of my head, but less than 1).

 

[4RunnERD]

The transfer case ratio is always going to be 1 unless you are in 4Lo. The transmission ratio depends on what gear you are in. If you were doing 65+mph, you'd probably want to plug in our OD ratio (I don't know what it is off the top of my head, but less than 1).

Good to know. I noticed in your signature you have a V8 4th Gen with the taller Revo's. Were you able to notice a difference in in torque or acceleration while driving?

 

[4RBob]

Good to know. I noticed in your signature you have a V8 4th Gen with the taller Revo's. Were you able to notice a difference in in torque or acceleration while driving?

It was so long ago I upsized, it's hard to remember. I think I remember "barely" noticing a difference, but the low end torque of the V8 is MORE than adequate to handle such a small difference in tire size.