Speedometer error - JKowners.com : Jeep Wrangler JK Forum
 
LinkBack Thread Tools Display Modes
post #1 of 10 Old 09-24-2008, 10:53 AM Thread Starter
jct
Wheeler
 
jct's Avatar
 
Join Date: Jun 2008
Location: PGH Pa
Posts: 29
Feedback: 0 reviews
Speedometer error

I plan on putting larger tires on my JK soon and was wondering if the dealer can re-flash the computer to adjust the speedo to the larger tires? Anyone have any idea?
J
jct is offline  
Sponsored Links
Advertisement
 
post #2 of 10 Old 09-24-2008, 10:55 AM
Granite Guru
 
Join Date: Aug 2008
Location: Sparks, NV
Posts: 326
Feedback: 0 reviews

Ive heard yes and no. I talked to one of my local dealers yesterday and they said they didnt think they could change the speedo past the factory tire sizes, but said bring it in and they will play around with it. It makes me think that they dont have a clue.

Of course this was the same dealer that said getting the u-connect to work in my JK would be impossible
Imkunfused is offline  
post #3 of 10 Old 09-24-2008, 10:55 AM
Newbie
 
Join Date: Sep 2008
Posts: 7
Feedback: 0 reviews

Just had 35in rubber put on and the Dealership recal'ed the speedo for me.. Cost about $45 on my end.. I trust that it was done correctly... All it took was about 15 min and a computer..
Explore is offline  
Sponsored Links
Advertisement
 
post #4 of 10 Old 09-24-2008, 11:27 AM
Granite Guru
 
tgrt's Avatar
 
Join Date: Apr 2008
Location: Carrollton, GA
Posts: 441
Feedback: 0 reviews

The answer is "no" unless something has changed with the systems that the dealer has. When I first investigated this I sat down with the service manager and their Starscan tool and it only provided a limited set of choices for tire sizes and gear ratios.

Based on that information in order to get a correct speedometer you will need to go with an aftermarket programmer like the Hypertech Max Energy. I believe there are others out there, but I went with the Hypertech.

2007 JK Rubicon
Clayton Offroad 3.5" | 35" Nitto Mud Grapplers | Cragar Soft 8s | JE Reel 1350 drive lines | Alloy USA front axle shafts
tgrt is offline  
post #5 of 10 Old 09-24-2008, 01:02 PM
Rock God
 
Bigjerm's Avatar
 
Join Date: Oct 2007
Location: GA
Posts: 1,071
Feedback: 0 reviews

Quote:
Originally Posted by tgrt View Post
The answer is "no" unless something has changed with the systems that the dealer has. When I first investigated this I sat down with the service manager and their Starscan tool and it only provided a limited set of choices for tire sizes and gear ratios.

Based on that information in order to get a correct speedometer you will need to go with an aftermarket programmer like the Hypertech Max Energy. I believe there are others out there, but I went with the Hypertech.
x2. My first JK came from the dealer with a lift and 35's yet they had no way to re-flash the computer past the Rubicon 32" tires. If I were you Explore I would be going back and asking to see their program to program to 35's and get your money back.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

2006 LJ - current
2007 4dr Rubicon - sold Project- JK
2007 2dr X - sold JK-forum
Bigjerm is offline  
post #6 of 10 Old 09-24-2008, 01:23 PM
Granite Guru
 
JeepThing's Avatar
 
Join Date: Oct 2007
Location: Nevada City, CA
Posts: 428
Feedback: 0 reviews

[QUOTE=tgrt;38953]The answer is "no" unless something has changed with the systems that the dealer has. When I first investigated this I sat down with the service manager and their Starscan tool and it only provided a limited set of choices for tire sizes and gear ratios.QUOTE]


x3 The dealer could not program for 37's and 5:13 gears. I went the Hypertech route.
JeepThing is offline  
post #7 of 10 Old 09-28-2008, 10:58 PM
Rock God
 
yoda13's Avatar
 
Join Date: Sep 2008
Location: Texas
Posts: 1,087
Feedback: 0 reviews

Yeah, you will need the Hypertech...Explore, you should go get your money back...
yoda13 is offline  
post #8 of 10 Old 09-30-2008, 08:16 PM
Newbie
 
CGScotty's Avatar
 
Join Date: Sep 2008
Location: Spring Lake Michigan
Age: 44
Posts: 3
Feedback: 0 reviews

I bought the hypertech when I went to 35's.
CGScotty is offline  
post #9 of 10 Old 09-30-2008, 09:07 PM
Granite Guru
 
TEEJ's Avatar
 
Join Date: Nov 2007
Location: Lawrenceville, NJ
Posts: 275
Feedback: 0 reviews
Talking

Last time I heard, the dealers can't go larger than a 32" tire.

There are aftermarket solutions, and, its quite possible that an individual dealer invested in equipment that can perform additional calibrations.

An easy way to check for free, to see if you are calibrated...

Just hit the hwy, and look for those mile markers every 1/10 of a mile...

Go an indicated 60 mph on your speedometer, and, see if you go one mile according to the mile markers (NOT your odometer!) every 60 seconds.

If you are going a mile a minute at an indicated 60 mph...you're golden.



If it takes closer to a mere 55 seconds (Anything less than 60 seconds per mile...), well, you are NOT golden.

If for example the dealer calibrated for 32's, and you have 35's...you'd be going about 8.6% faster than the speedometer said you were, and about 8.6% further than the odometer said you were.

So - instead of 60 seconds to go a mile, you'd cover the mile 8.6% faster, or , in about 55 seconds.



Hope that helps!

PS - finding one of those unmanned speed trap sign things...or, using a GPS that gives your ACTUAL speed, and comparing it to what the speedometer says, would ALSO answer the question.

You'd need to be going at least an indicated 60 mph to be going fast enough to tell the difference with any reliability though.


- TEEJ

2008 JK 4 Dr X. 5 Speed, LSD, JKS QD, 3.73 Diffs. Husky Liners and Daystar Hood Wranglers. Pine Stripes.

Last edited by TEEJ; 09-30-2008 at 09:11 PM.
TEEJ is offline  
post #10 of 10 Old 10-01-2008, 08:10 AM
JR
Rock God
 
JR's Avatar
 
Join Date: Oct 2007
Posts: 541
Feedback: 0 reviews

We work very closely with a local dealership who does alot of modding to JK's right off the lot.

Their answer is the same, 4.10's and 32's are the furthest they can go (existing factory programs)

Jason from RJR Off-Road

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

coupon code = JKOWNERS
JR is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JKowners.com : Jeep Wrangler JK Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome