Reflash for larger tires...help

[MartyK]

I thought I once read a thread, that reflashing the computer for larger tires was a simple 10 minute job. Can anyone point me to that thread?

I stopped by the dealer this morning that I bought my truck from and he told me it would take the technician about an hour and would cost me $80. 00. I told him I have the revolutions per mile, which is 593 for my 35" Toyos. I believe this info is entered into the abs section. The write-up guy looked at me like I was speaking another language.

Does this sound right or am I all screwed up?



Thanks.

 

[JVolpe]

Well you are right, it is about 5 minutes at the most after the DRBIII is connected to the truck. Four or five menus in, somewhere in the ABS stuff is a place to change the "Pinion Factor" to the corrected rpm.



My dealer service manager did it for free in about 6 minutes. I said what do I owe you, he said "just remember where your service work is done", and I do.



I have seen similar posts about dealers charging that and more. I suspect the hour talk is just to make you think it is worth the cost. Just my . 02.

 

[AlexWV]

The dealer where I bought my truck said they'd charge 1. 5 hours and that they have to first get in contact with STAR to get the right info to program and also to inform STAR of this change. Who's STAR anyway? I told him I had it done for free on my Hemi at another dealer - no STAR bs and no 1. 5 hours - and I expect the same treatment from this place since I bought my truck here. No dice.



So I went to the other dealer and they did it for free again, while I waited, and they were busy that day. I'd say it takes less than 5 minutes.

 

[Cattletrkr]

I paid $32. 50 to get mine done, 0. 5hr labor. Ain't so bad when you consider that a few months later same dealer warrantied and aftermarket u-joint for me.

 

[Blakers]

Unless you have an automatic I don't think it's worth doing. The tires will throw the speedometer off a little, but check it with a hand held gps and go from there.

 

[AlexWV]

Depending on your tires, it could throw it off a lot. I ran BFG 315 for a while and it was off 9. 1% verified with a GPS. With 285s it was off 4. 3%. With the 35" Toyos, you are going to be over 10% off.



If anybody is interested, the BFG285 revs/mile listed is 634 which I used and am now off by 0. 6% which means if my odometer says I have travelled 1000 miles, I have really gone 1006 miles. A number like 630 or 631 should get you very close to bang on.

 

[JCleary]

I thought I once read a thread, that reflashing the computer for larger tires was a simple 10 minute job. Can anyone point me to that thread?

I stopped by the dealer this morning that I bought my truck from and he told me it would take the technician about an hour and would cost me $80. 00. I told him I have the revolutions per mile, which is 593 for my 35" Toyos. I believe this info is entered into the abs section. The write-up guy looked at me like I was speaking another language.

Does this sound right or am I all screwed up?



Thanks.

I had my dealer do it for my Toyos, and I think 593 is a bit too little. The speedo seems close at low speeds, but I think it reads a few mph high at highway speeds. It *is* programmed in the braking circuit, by setting the pinion factor. Enter pinion factor into the search feature and you'll find some info. The tech has three choices. Two tire sizes, and a third where he/she can program revs per mile. It is definitely a 10 minute or less job if the tech knows what they're doing.



If my morning fog brain is working right, I think a higher number will bring the indicated mph down. Next time I'll have him program for 600 and see what happens. I'll be swapping for my BFG 285's when the snow starts (I'll have them set to the stock size), so next spring I'll know if I'm right.



off topic---Those Toyos are sweet, but wearing faster than I anticipated, even with 5k mile rotations...

 

[BHolm]

On my BFG 285's I used 632 and the truck is within . 5mph according to my gps. I would think that with 315's it is definately worth doing, the difference has to be a good 5mph and that can get you a ticket if you forget. My dealer also did it for free with no appointement. I guess I should be thankful I have a good dealer, $80 :{ thats crazy.

 

[Greg Boardman-RIP]

Tire Size Product Code Rim Width Range (inch) Tire Weight (lbs. ) Tread Depth Tread Width Inflated Dimensions Static Loaded Radius (inch) Max Load (lbs. ) Max Pressure (PSI) Revs Per Mile

Overall Diameter (inch) Overall Width (inch)

35x13. 50R15 114 C/6 361000 8. 5 - 11. 0 84 21 34. 8 14. 4 15. 2 2600 35 596

33x13. 50R15 119Q C/6 360290 8. 5-11. 0 75 21 33. 1 13. 9 15. 4 2270 35 628

37x14. 50R15 120Q C/6 360260 10. 0-12. 0 94 21 36. 7 15. 6 17. 0 3080 35 566

LT265/75R16 123P E/10 360320 7. 0-7. 5-8. 0 58 19 31. 8 10. 8 14. 8 3415 80 651

LT285/75R16 126P E/10 33x11. 50R16 360280 7. 5-8. 0-9. 0 68 19 33. 0 11. 6 15. 4 3740 80 628

LT315/75R16 127Q 360230 8. 0-8. 5-10. 0 76 21 34. 9 12. 9 16. 2 3860 65 595

38x14. 50R16 129Q D/8 360250 10. 0-12. 0 99 21 37. 7 15. 6 4080 50 550



35x12. 50R17 125Q E/10 360310 8. 5-10. 0-11. 0 83 21 34. 8 13. 2 16. 2 3640 65 596



37x13. 50R17 131Q E/10 360270 8. 5-11. 0 93 21 37. 1 14. 6 17. 2 4300 65 560

38x15. 50R18 128Q D/8 360180 11. 0-12. 0-13. 0 106 21 37. 7 15. 9 17. 5 3960 50 550

35x12. 50R18 123Q E/10 360090 8. 0-10. 0-11. 0 81 21 35. 0 13. 2 13. 7 3415 65 593

38x15. 0R18 128Q D/8 360180 11. 0-12. 013. 0 106 21 37. 7 15. 9 17. 5 3470 50 550

33x12. 50R18 118Q E/10 360340 8. 5-10. 0-11. 0 75 21 33. 0 12. 7 15. 3 2910 65 630

37x13. 50R18 124Q D/8 360300 8. 5-11. 0 93 21 37. 0 14. 2 17. 2 3525 50 523

33x12. 50R20 114Q E/10 360330 8. 5-10. 0-11. 0 72 21 33. 0 12. 6 15. 3 2600 65 630

38x15. 50R20 125Q D/8 360190 11. 0-12. 0-13. 0 101 21 37. 7 15. 9 17. 5 3640 50 550

35x12. 50R20 121Q E/10 360240 8. 5-10. 0-11. 0 80 21 35. 0 13. 0 3195 65 592

37x13. 50R20 127Q E/10 360220 8. 5-11. 0 94 21 37. 1 14. 0 3860 65 560

40x15. 50R22 127Q D/8 360200 11. 0-12. 0-13. 0 110 21 39. 7 15. 9 18. 5 3860 50 522

37x13. 50R22 123Q E/10 360210 8. 5-11. 0 90 21 37. 1 14. 0 3420 65 560

37x13. 50R24 120Q E/10 360350 8. 5-11. 0 89 21 37. 0 13. 6 17. 2 3085 65 561





Bold designates measuring rim width. All Toyo brand tires are subject to continuous development. Toyo Tire (U. S. A. ) Corporation reserves the right to change construction, materials or specifications without notice or obligation. Contact your Toyo dealer or Toyo Tires for current information.

 

[Greg Boardman-RIP]

The last number in your tire size is the correction number.

 

[MartyK]

Thanks for the help. I'll let you know what happens.



Marty

 

[BHolm]

Keep in mind that all tires do not measure equally. Get the revs/mile for your exact tires.

 

[mdepot]

Unless you have an automatic I don't think it's worth doing. The tires will throw the speedometer off a little, but check it with a hand held gps and go from there.

If you have ABS, can't not having the right value in there cause the ABS to activate too early or too late?

 

[Matt400]

Good news-



I just received my latest scanner software update from Snap-On and its in there!!

I can program tire size or plug in a tire RPM figure.



This means local independent shops that have current Snap On software will be able to do this function without a DC specific DRBIII.

 

[Blakers]

If you have ABS, can't not having the right value in there cause the ABS to activate too early or too late?

It does't bother mine at all.



It did throw my speedometer off a little, but I just use my GPS. BTW, with the stock 265 tires, the speedometer was showing about 3 mph too fast.



Blake

 

[rbattelle]

I just received my latest scanner software update from Snap-On and its in there!!

I can program tire size or plug in a tire RPM figure.

Oh, man I wish I lived near you. I'm going to upgrade my OBD-II system to be CAN-BUS compatible... I wonder if I might be able to do the same thing...



-Ryan

 

[JasonP]

Speedometer ok fuel mileage sucks

the speedometer accuracy is not the biggest concern it is close cnough to my gps, the drop in fuel mileage is unacceptable (18-19 to 14-15) The tires are 285-70-17 goodyear wrangler mtr. would a less agressive tire be better or would resetting the pinion factor help?

 

[tgbol]

MartyK

Where do you live. I am in the Los Angeles area and I will do it for you. Tom

 

[rbattelle]

would a less agressive tire be better

Probably.

would resetting the pinion factor help?

No.



That change in mileage is awful severe for just 285-series tires. I would expect little or no change in MPG going from 265 to 285... am I wrong? What pressure are you running?



-Ryan

 

[mdepot]

... the speedometer was showing about 3 mph too fast.

Note when speedometers are off, they are not off by a fixed MPH value. It's a common misconception that you can just add or subtract a certain MPH value back to the reading to figure your real speed. It actually works more like a percentage error, so if it's off by 3 MPH at 20, it might be off by 6 MPH at 40 and off by 12 MPH at 80.