CorvetteForum - Chevrolet Corvette Forum Discussion

C6 Tech/Performance LS2, LS3, LS7, LS9 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace
Sponsored by:
Sponsored by:

speedometer correction

   
Old Oct 11, 2006 | 02:24 AM
Share
  #1  
Stingray23's Avatar
Stingray23
Thread Starter
Le Mans Master
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2006
Posts: 8,721
Likes: 707
From: New York
Default speedometer correction
will larger wheels and tires throw off my speedometer? i'm upgrading to 19's and 20's with 305-25-20 tires out back.
Reply
0
Old Oct 11, 2006 | 02:55 AM
Share
  #2  
cbrf4i1's Avatar
cbrf4i1
Drifting
 
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
Default
Originally Posted by Stingray23
will larger wheels and tires throw off my speedometer? i'm upgrading to 19's and 20's with 305-25-20 tires out back.
yes, you new combo will only give you 26 inch in over all diameter. you speedo will be 4% from before.
Reply
0
Old Oct 11, 2006 | 03:02 PM
Share
  #3  
Stingray23's Avatar
Stingray23
Thread Starter
Le Mans Master
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2006
Posts: 8,721
Likes: 707
From: New York
Default
Whats the best way to correct that? Tune?
Reply
0
Old Oct 11, 2006 | 04:18 PM
Share
  #4  
LS1LT1's Avatar
LS1LT1
Team Owner
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Feb 2001
Posts: 27,246
Likes: 130
From: Short Hills, NJ
Default
Originally Posted by Stingray23
Whats the best way to correct that? Tune?
Yes, it's actually the ONLY way...doesn't need a full dyno tune of course, just the basic laptop in the driver's seat thing.
I thought the manual C5s corrected for gears/tires automatically, not sure about the C6s...I know autos needed the tuning software to do it though.
Reply
0
Old Oct 11, 2006 | 05:07 PM
Share
  #5  
cbrf4i1's Avatar
cbrf4i1
Drifting
 
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
Default
or get taller tire / wheel combo.
Reply
0
Old Oct 11, 2006 | 06:15 PM
Share
  #6  
Indy-hp's Avatar
Indy-hp
Le Mans Master
20 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Nov 2005
Posts: 6,099
Likes: 64
From: Houston TX
St. Jude Donor '09
Default
Originally Posted by cbrf4i1
or get taller tire / wheel combo.
When going to a larger wheel size, the best thing to do is to compensate with a lower profile tire so that the overall diameter does not change and the speedometer will still be accurate. Good tire shop will know what size tire is needed for 1" larger rims, and some tire websites I've seen even have a calculator for that.
Reply
0
Old Oct 11, 2006 | 07:07 PM
Share
  #7  
Stingray23's Avatar
Stingray23
Thread Starter
Le Mans Master
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2006
Posts: 8,721
Likes: 707
From: New York
Default
well, I think the stock rear tires are 285/30/19. the new tires are 305-25-20. does that make up for the difference so i wont need a tune? would anyone with experience please lend a hand. there are a lot of guys on this forum with upgraded wheels and tires. thanks.
Reply
0
Old Oct 11, 2006 | 07:10 PM
Share
  #8  
Stingray23's Avatar
Stingray23
Thread Starter
Le Mans Master
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2006
Posts: 8,721
Likes: 707
From: New York
Default
BTW, the rear wheels are 20x12(if that helps)
Reply
0
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old Oct 11, 2006 | 07:13 PM
Share
  #9  
cbrf4i1's Avatar
cbrf4i1
Drifting
 
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
Default
Originally Posted by Stingray23
well, I think the stock rear tires are 285/30/19. the new tires are 305-25-20. does that make up for the difference so i wont need a tune? would anyone with experience please lend a hand. there are a lot of guys on this forum with upgraded wheels and tires. thanks.
stock rear is 285/35/19....see if you can find 305/30/20 tires. that will get you almost exactly oem over all hight.
Reply
0
Old Oct 11, 2006 | 07:50 PM
Share
  #10  
mlongo99's Avatar
mlongo99
Le Mans Master
20 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Nov 2004
Posts: 6,566
Likes: 2
From: Goleta CA
Cruise-In VIII Veteran
Default
Originally Posted by LS1LT1
I thought the manual C5s corrected for gears/tires automatically, not sure about the C6s...I know autos needed the tuning software to do it though.
C6 does too, but they cannot compensate for tire changes. Vehicle speed/distance is calculated by measuring rotation of the wheel, therefore the gear you're in or the differential ratio is irrelevant to the calculation. But the calculation is based on the factory tire circumference, so changing that will affect the speedo/odometer.

This is the same with automatics, they just require tuning to correct the shift points.
Reply
0

Get notified of new replies

To speedometer correction

Back to Subforum
C6 Tech/Performance
View Next Unread
Pressure sensors/ Track tires


Thread Tools
Search this Thread
Search this Thread:

Click for Advanced Search

Click for Advanced Search
Reply Closed Thread Share
Forum Jump
Trending Topics

All times are GMT -4. The time now is 05:07 PM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE