Have been trying to figure out how to get the right tire size figured out forever and everything I've tried doesn't seem to be working unless I'm missing something. Truck is a 98 k1500, every time i go into the tire/gear wizard its setup as followed tire tire: .74 with gears: 37.3 if i punch in the correct size 34.6 it wants to multiple by 46. Speedo is out about 10 on highway and 5 in town i should mention, any help would be appreciated
Hey wouldn't it be cool if there were a way for you to post your file so other people could look at it and maybe spot the issue?
my bad completely forgot lol
Are you putting the decimal in the wrong place for your gear ratio? In your post you have 37.3 and actual should be 3.73.
Well I just tried to goof it up as bad as I thought you may have but, it won't let you get it that far off. When I input the numbers you gave, the multiplier goes to 29.43.
Last edited by abc; 3 Weeks Ago at 08:05 AM.
VSS pulse per rev should be 40.Originally Posted by Tkasprick
Did you accidentally change it to 1? Do you have your stock file to compare to?
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Yea that was a typo sorry, yea just started digging into it again too an nothing works haha
Haven't touched that, its still set to 1 in the stock file as well
What is the actual tire size on the tire, not the tire height.
315/75r16 comes to 34.6
What was the stock tire size on the truck?
I think 265/75 r16 I'm pretty sure
Give me a little time and I'll have something for you to try. I don't use HPT to correct gear/tire size on 98-99 black box PCMs. It doesn't work very good.
Yea it's pretty shitty honestly, be switch to 0411 pretty soon. Appreciate it man!!
Load this as a compare file. Copy over all the speedometer settings. If you have already scaled the shift and TCC lock up tables, return them all to their stock settings. Then use the manual scale function in the tire wizard and use 1.095 as a multiplier.
Thank you man! I'll give that a shot when I get home
And don't go my what your cluster shows for MPH. There are free speedometer apps for your phone that use gps. Compare what the scanner shows for MPH vs what the gps shows.
Will do! I appreciate the help I'll get it loaded to the truck tomorrow and get back to you, could not for the life of me figure out how to go about it
I use Tunercat to make the changes, then flash it to a PCM, then read it back out with HPT. It is not based off your file, Just another 98 K truck. That is why you need to copy the settings to your file.
Been meaning to ask. What does the multiplier do? Why would you change it from 1.0, instead of just modifying the tire size to more closely match the actual diameter?
It is manually scaling the shift and TCC lock up tables up or down by the tire size difference. The wizard doesn't work well on 98-99 black box PCMs entering tire sizes. In this case he is manually entering the parameters in the speedometer tab.
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