Speedometor/mileage change w/ 35" tires?

[JBoone]

My 05 4x4 373 gears had 265's on it and I put 35x12. 50's on. I don't know what I need to do to get my speedometer and mileage to be correct with the 35's. I'm going on about a 1000 mile trip this weekend and want to know how fast I'm going and my mileage (approx. ) Has anyone put on 35's that knows the true readings of speedometer and mileage? Thanks a lot for the help.

One more question. If I travel 1 mile with 35's. About how far have I really traveled?

 

[67guzzler]

My 05 4x4 373 gears had 265's on it and I put 35x12. 50's on. I don't know what I need to do to get my speedometer and mileage to be correct with the 35's. I'm going on about a 1000 mile trip this weekend and want to know how fast I'm going and my mileage (approx. ) Has anyone put on 35's that knows the true readings of speedometer and mileage? Thanks a lot for the help.

For me, 70 was about 63. 5 mph before I got mine done. I got mine done at the local dealer. See:



https://www.turbodieselregister.com/forums/showthread.php?t=138223



Good luck!

 

[Bob4x4]

Its just a matter of programming the correct pinion factor into the c. a. b.



Bob

 

[JVolpe]

This tire calculator is pretty accurate.

http://www.1010tires.com/TireSizeCalculator.asp



It shows your tire change variance is: Speedometer Difference: 10. 03% too slow.



Your new RPM shows 598.



Dealer can reprogram the "Pinion Factor" in about 5 minutes if they know how and are willing to do it.

 

[JCleary]

I had mine reprogrammed for 593 revs/mile (as per Toyo spec)



It's about 2mph fast on the speedo at 70mph indicated.



I'm switching back to my 285's for the snowy season. Time to reprogram again. Only bummer is that the local dealers all want one hour minimum at $120/hr.



I lost 1. 5 to 2 mpg with the bigger tires, hand calc.

 

[AndyMan]

I put on MasterCraft Courser C/T 35x12. 50x17. Measurements, calculations and TDR searches turned up 601 revs per mile. I have a friend with a repair/performance garage, he used a SnapOn tool to set my pinion factor. After changing it, a fellow TDR member had a portable GPS. My speedo was dead accurate all the way to 80mph (fast as I could get the truck in this particular area).

I think my mileage has actually improved. I'm only turning 1900RPM's @ 70 MPH, whereas with the 265's I was turning 2000 @ 70 MPH. I have the 3. 73 R&P 11. 5" axle

 

[JBoone]

Thanks for all the help. The info. helped me a lot. One more ?. If I travel a mile how far do I really travel with 35's. ?

 

[4xquadrod]

I took my truck to a speedo shop after installing 35s. I was accurate up to 40mph. At 70 mph I was acutually at 73 mph.

 

[67guzzler]

Thanks for all the help. The info. helped me a lot. One more ?. If I travel a mile how far do I really travel with 35's. ?

Prolly around 9/10 of a mile +/-

 

[Giachino]

for those with a 610, 3. 73. , auto and 35" tires... . what was the perfromance impact for loaded / unloaded? I like my gearing as is 265's/3. 73... but also want to get bigger tires without changing my gearing $$$

 

[NLamke]

I've got 610, 373's, auto transmission, and 35's. I love it! If your odometer says you have traveled one mile, you have really gone 1. 1 miles. If you have covered an actual mile, your odometer will say 9/10 mile. Everything will be off 10%. I installed the Edge Juice w/ Attitude, and use that for speed correction, verified with GPS, I'm within 1/2 mph accurate. The juice also put my overhead mileage back on to accurate readings. I really haven't noticed any performance difference, especially with the chip. If you don't recalibrate the speedo, just add 10% to what the speedo is saying and you'll be within one mph accurate. ie if speedo says 60, you're really going 66, if it says 80, you're really going 88, if it says 20, you're really doing 22. Simple enough?

 

[Giachino]

Did you put a leveling kit or anything else on your truck for the 35's? Do they rub lock to lock?

 

[strokerschmoker]

The superlift truspeed calibrator is another option if your one who changes tires alot. It is a little expensive but its a nice piece

 

[67guzzler]

Did you put a leveling kit or anything else on your truck for the 35's? Do they rub lock to lock?

My 315's (34. 86" diameter) rub at full lock. Moreso to the righ than left. It's controllable & avoidable tho.

 

[JVolpe]

I have 315s on stock 17x8 Dodge rims with a DayStar 2" leveling kit. Mine have never rubbed. Over 30,000 miles. I do have Rancho 9000xs set on 7(stiff) in front, whether that helps at full lock or not I doubt it. I try not to do full lock if at all possible, just seems hard on front end.

 

[makelemen]

Until you get a fix, for this trip, you can use the highway mile markers. Go 10 miles and compare that to your odometer. If 10 highway = 9 odometer miles, you are 10% off. You can assume 90 mph speedometer = 100 real mph. My ex-wife got pulled over after I put 31's on a 88 toyota truck. I told the cop that I forgot to tell her the speedometer was off. Didn't work.

 

[NLamke]

My 35's rub very slightly. It was a little worse before I put the leveling kit in, but still not bad, only rub them once a month or so, and it's so slight I hardly notice it. That's on stock rims. I have a bunch of different pics in my gallery too if interested, both before and after leveling kit as well.

 

[Matt400]

Any independent repair shop that uses the Snap On Modis, Solus or MT series scanners can now do the reprogram if they have the latest 04 software.

All they need to do is tell the scanner its an 04 model and it will let you into the 05 software for pinion factor recal. Tire RPM or size can be chosen.