Tell me this can't be true guys . My new dealer whom which is pretty good with taking care of customers told me today that on the 05's you can't recalibrate the speedo for the 315's i'm running . I remember reading on here that you just have to reset the revs per mile to 606 . I told him i'll check with my " Cummins Buddies " and print him out the directions on how to do it . I hope i'm not wrong . I did a search on here and found a few posts that say it can't be done on an 05 but i swear i also remember reading it can be done . Any help guys ??????

 

Hey,
I'm pretty sure it's 601 revs per mile. Maybe someone else will chime in on that.

Whoever you talked to thinks that the 315 tire size is not in the computer so it must not be able to do it. WRONG. Have the tech click on "other" under the tire sizes and then choose revs per mile and punch it in. Takes less than five minutes.

hope this helps

Jamie

 

Just had my 05 done today for my new 315's, cant remember the revs but we looked it up on www.tirerack.com. It was either 601 or 606, took him all fo 2 minutes. Keep the faith

 

Thank you very much gentleman . Now i know why i love this site Its kinda sad though when you have to go to the dealer with proof and show them how to do something BTW it is 601 revs for the record . Thanks again

 

O5CT, The website may say 601, But some have found 606 to be more accurate when the tires are new. As the tires wear of course revs change. 18/32 tread depth means that 1/2 worn radius is 9/32 less. ks

 

are 315's the biggest they can go? how about 38's? thx

 

They set mine and I'm running BFG AT's 37X12.50's

Checked with my GPS it's dead nuts accurate

 

I recall reading on here about some guys with the 06 trucks having trouble getting theirs calibrated.

I had mine recalibrated when I went to 285's. Mine is an 04.5, but I don't think there is any differences between the 04.5 and 05 as it relates to that.

Something changed on the 06 trucks causing that problem and I bet your dealer is confused between the model years.

 

u guys should have a dealer like prebul of chattanooga. he wouldnt do it. said it was against federal law. couldnt quote the statute though. guess when my wife buys her new jeep we will pass up the"prebul" group of chatt town.

 

It is sad, but doesn't it make you feel good that you know more about your truck than the guys that work on it. . . Wait that should scare you, not make you feel good. . . I need more sleep

 

The 06 uses the Starscan and I've heard guys say it can't adjust tire sizes, the 05 however used the DRB. Under tire sizes there is an option for "other" sizes, select that and enter the revs per mile and your all set.

 

06 you can set the tires as long as they are one of the ones listed in the scanner...and the largest it has is 285x70x17 which also happens to be the largest tire they offer OEM on the Powerwagon....to my knowledge.

My dealer thinks they can get them to fix it so they can manually enter....I guess I will go by tomorrow and see how much pull they actually have with the software guys. If not then mine will either stay 285x70x17 or find another tire size that has same revolutions but in different ratio like 275x50x20 which i am told is a 33 inch tire....same as 295s almost.

Oh well....

 

The 315's are 606 per mile. Measured loaded roll out of tire and did the math. Had truck recalibrated to 606 revs per mile. Checked with two different GPS's and its dead on. Remember 606.

 

OK, so how come when you look up the 315 on BFGs website and check the specs it shows 601 revs per mile??

I might need mine recalibrated to 606?

That might be why I'm only getting 14.6 mpg!!!!!!!!!

Jamie

 

The 06 computer has 305's in it. I just had mine done. There is no 295 though which I put on so it was either 285 or 305. I went with the 285 and just add about a mile an hour.