Go Back   EcoModder Forum > EcoModding > Off-Topic Tech
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-24-2019, 01:01 AM   #1 (permalink)
Master EcoModder
 
Join Date: Aug 2018
Location: USA
Posts: 455

Jeep - '97 Jeep Cherokee Sport
90 day: 19.36 mpg (US)

Blueberry - '07 Toyota Camry SE
Thanks: 180
Thanked 101 Times in 77 Posts
Gearing and tire size

So I'm about to commit the cardinal sin of ecomodder and get a lift on my Jeep and bigger tires. I'm wondering how I can calculate the final gearing so I can compare my new setup to stock.

The stock specs of my Jeep are:
3.54:1 axle gears
225/75R15 tires (I think approximately 28" diameter)

How can I compare that setup to a different one?

This is something an example I have in mind:

4.56:1 gearing
33x10.5 tires

Please post how you come to your answer so I can do it myself for different scenarios. I want to pick the best gear and tire combo for what I'll be using my jeep for.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-24-2019, 10:34 AM   #2 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,373
Thanked 2,172 Times in 1,469 Posts
This site offers the formula for how to use tire size to calculate tire diameter:
https://auto.howstuffworks.com/auto-...size-chart.htm

tire diameter:

(CROSS SECTION WIDTH x 0.ASPECT RATIO x 2 ÷ 25.4) + WHEEL DIAMETER = OVERALL TIRE DIAMETER

For Example:

235/45ZR-17

(235 x 0.45 x 2 ÷ 25.4) + 17 = 25.327"

And here's a calculator for the rest of your query:
https://tiresize.com/gear-ratio-calculator/
__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



  Reply With Quote
The Following 2 Users Say Thank You to California98Civic For This Useful Post:
Fat Charlie (03-24-2019), Taylor95 (03-24-2019)
Old 03-24-2019, 12:48 PM   #3 (permalink)
Rat Racer
 
Fat Charlie's Avatar
 
Join Date: May 2011
Location: Route 16
Posts: 4,150

Al the Third, year four - '13 Honda Fit Base
Team Honda
90 day: 42.9 mpg (US)
Thanks: 1,784
Thanked 1,922 Times in 1,246 Posts
Take the tire size calculator difference and multiply all your distance related math with it. A ScanGague or UltraGague comes in handy because you can simply calibrate your odometer readings through it.
__________________

Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

  Reply With Quote
The Following User Says Thank You to Fat Charlie For This Useful Post:
Taylor95 (03-24-2019)
Old 03-24-2019, 03:03 PM   #4 (permalink)
Master EcoModder
 
Join Date: Aug 2018
Location: USA
Posts: 455

Jeep - '97 Jeep Cherokee Sport
90 day: 19.36 mpg (US)

Blueberry - '07 Toyota Camry SE
Thanks: 180
Thanked 101 Times in 77 Posts
Quote:
Originally Posted by Fat Charlie View Post
Take the tire size calculator difference and multiply all your distance related math with it. A ScanGague or UltraGague comes in handy because you can simply calibrate your odometer readings through it.
You know, I realized that I think I've been calculating my distance traveled wrong. I've been assuming that my stock tire size was 29 inches instead of about 28... So I should be multiplying my distance by 1.07 instead of 1.04
  Reply With Quote
Old 03-24-2019, 03:15 PM   #5 (permalink)
Master EcoModder
 
me and my metro's Avatar
 
Join Date: Jun 2008
Location: Oregon
Posts: 556

Economy Saturn - '02 Saturn L200
Thanks: 255
Thanked 198 Times in 156 Posts
There is a sticker in your door jam that that states what size tire came stock on your vehicle. Look on both sides if you don’t find it near the driver’s door.
__________________
02 Saturn L200 5 speed- 265k miles
84 Gmc 6.5 na diesel K30 4x4, TMU
2006 Lincoln Navigator, 215k miles
  Reply With Quote
The Following User Says Thank You to me and my metro For This Useful Post:
Taylor95 (03-26-2019)
Old 03-26-2019, 12:35 PM   #6 (permalink)
Master EcoModder
 
Join Date: Aug 2018
Location: USA
Posts: 455

Jeep - '97 Jeep Cherokee Sport
90 day: 19.36 mpg (US)

Blueberry - '07 Toyota Camry SE
Thanks: 180
Thanked 101 Times in 77 Posts
Thanks! All the replies are very helpful. It helped me realize I've been calculating my odometer wrong.
  Reply With Quote
Old 03-26-2019, 01:56 PM   #7 (permalink)
Rat Racer
 
Fat Charlie's Avatar
 
Join Date: May 2011
Location: Route 16
Posts: 4,150

Al the Third, year four - '13 Honda Fit Base
Team Honda
90 day: 42.9 mpg (US)
Thanks: 1,784
Thanked 1,922 Times in 1,246 Posts
Yeah, there's a lot of zigging and zagging and double negatives. But it does what you want it to do.

__________________

Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com