Discussion in 'Chassis - Suspension - Wheels and Tires' started by NitroChemist, Sep 17, 2017.
Wow, that sucks. Sometimes I wish there were limits!!
Can the dealer program 245/70R16 into the ECM? Or do tire size 30"? Another trans flash wouldn't be to expensive. The ECM is learning the new tires. I notice it shifts differently. RPMs are down. It will take a few tanks to see mileage is affected. For now, I'm using a +2.4% difference between stock and new tire sizes.
I bet there won't be difference. While you may have slightly better mileage on HWY, any acceleration will be worse due to "heavier" gear.
There are only 3 tire size options that a dealer can program into the computers. P225/75R16, P235/65R17, and P245/50R20.
Of the 3, the 20" has the largest diameter at 29.65”.
I don't think they need to be programmed. Circumferences are almost identical for all 3 tires. (within 1-2% what is less than the resolution of the speedometer)
Programming should be advanced to install any tire size we wanted. EPA
The torque converter is very loose. It's bad. I've driven all kinds of vehicles and this one has it the worst. A tighter converter would help but some people wouldn't like it. I had a GMC Jimmy programmed to lock the converter above 45 MPH instead of 50+. It gained 1 MPG in the city. The Nitro has similar weight. The main differences are first gear and 3.42 (GMC) vs 3.73 gears (Nitro). If I ever replace the trans, I'll definitely look for a better converter.
Do you have 42RLE or NAG1?
42RLE. It was flashed shortly after I bought it. One udpate was added. It make a nice difference. Shifts were better and firmer. Once in a while it will bang the gears hard on WOT.
What is the correct offset for a 16X8" wheel to be fender flush? I found some 16" Mickey Thompson's that will fit.
Good question. You may have to measure your current wheel backspace and extra distance needed to get to the well flair. Then use an on-line wheel calculator to compare the 2 setups.
Scar0, just purchase the tires outright. Then bring them back and ask if they'll install tires you purchased elsewhere. They'll usually do it. I had to do that a couple times at Sam's Club. This sue-happy world keeps companies from wanting to install other than OEM size tires on anything!
Found a local company willing to sell and install them. They came with in $100 of Costco price, and being local I can have my tires rotated for free here in town.
My Baby Has New Shoes
Finally went to purchase a matching spare tire. 245/70R16. Discount tire guys could not get it tucked up under the Nitro.
Told them to throw it in the back and I would mount it at home. WTH, yup the new slightly taller tire will not fit. The aftermarket Class III is a problem. After a few tries, I deflate the tire then wrench it up. I had to push on it to get it up. It fits once it's all the way up. I had to inflate it back up. Coming down shouldn't be easier. I hope.
When it's warmer, I drop it down again by deflating the spare. I'll trim a little off the hitch square tubing sticking inward toward the spare. Not much, just enough to wrench the spare back up.
Does anyone know the square size on the wrench mechanism? I tried several sockets but some would spin under weight. I might need to find a square socket to use a ratchet.
Your OEM jack handle extension should work on the spare lift mechanism.
You can measure that for size.
I've never been a fan of the 'under-the-rear' spare so I just mounted mine vertical, in the back,against the drivers side. It JUST fits inside without rubbing the rear hatch.
The OEM handles are about wallowed out. If I force the spare tire up, without trimming the hitch inside, I could break the mechanism. Or worse, wallow out the flimsy stock jack sticks. I want a socket size since I was trying to wrench it up and move the spare tire around at the same time. It's not easy reaching up high to turn the stock setup. I used a socket and ratchet to raise the deflated spare using the stock stick.
I agree with KansasNitro. Mines worse since I have a cargo area weather mat. I have to fold it over or take it out to wrench up the spare tire.
Now what size are the lugs? I'm heading to harbor freight for a breaker bar and one socket. They'll be stored with the other stock jack equipment.
Quick reference guide
Lugnuts: 3/4" socket, Thread size is a 1/2" X 20 TPI (threads per inch)
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