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Discussion Starter #1
I'm currently running stock 235s on my truck. Trying to figure out how much taller I should go, or how much a taller tire will help my highway RPMs. I realize I have to go wider as well. I'm thinking of going 285-75-16s. Does anyone currently run that size tire with 4:10s? If so what do your RPMs look like at 65? And 70 mph?
 

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I'm on 315/16's that physically measure 33" in their now late life. My speedo is about 9% lower than reality. I try to keep my tach in the 1900-2100 rpm range and that puts my speedo around 60 which in reality is around 65 mph. Not sure about 70. I know you're not asking but I like this setup because I like to drive slow anyway and my mpg/speed ratio is just about perfect for me. If I drive any slower I do not increase mpg and if I go faster it goes down a little.
 

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I've had 2557516 size, then just bought new 2857516. I think perhaps the perfect size would be 315/16's. I drive a lot of up and down hills about 45 to 50. I'd like to have a little lower rpm's when out of overdrive. The 315/16 would have some slight overdrive affect to them. When the 2557516's were on a relatively stock truck I pulled down 22mpg a couple times driving between 60 and 65 mph. I then made some new mods and installed new 2857516's and I can't keep my foot out it. It's much more fun to drive with the new found power. I don't care about fuel mileage. I have checked twice, been 14 to 16 mpg all around driving with a smile on my face.
 

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I am running 315/75/16 and they work well for the highway, I have noticed that the increased rotating mass has impacted my braking distances. The next set I'll be back down to a 285.
 

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Terminator Nation
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I ran Brdigestone 265s and 285s with about the same rpm as the stock 235s. About a 1/4" difference in size between the three tires. The change in aspect ratio made them about the same overall diameter. The speedometer was actually more accurate with the 285s than with the stockers when checking with a GPS. The larger sizes were wider so the milage did drop off using the larger tires compared to the stock tires due to increased rolling friction.
 

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At 70 mph im screaming at 2400rpm....305-70-16, 4.10s.....i do alot of highway driving more then anything and itd be nice to not be running it that high...
 

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Currently running 285 75R 16 dedicated winters on the white/silver and it has 4.10s much better than the 265's that the PO had on for highway driving. Thinking I'll (in time) be swapping to 3.55 or 3.73 when I do the D60 install on it. Or the other option is to go with 36" tires.... I don't tow lots so for me the 3.55 gears work best for what I do. The 97 sig truck has 315's and 3.55 and with the mods (more power) I really like how it lopes down the hiway in 5th. Conversely in the white truck you think you're just ripping along due to engine sound (based on the 97) and then you look at the speedo (and in the mirror) and you're actually holding up traffic..... I really like my 3.55 and 315 tires.

jrc
 

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I have to second the 315's with the 3.55. I think with heavy towing it would be too much, but with light towing and cruising it is nice, especially since i added the WW2 and put the 1.0 housing back on.
 

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STILL LEARNING
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I could not imagine 3.55s and towing. There are times I wish I had 4.30s in my tow rig.

But just cruising down the highway with no load, yes 3.55s would be nice
 

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I tend to prefer the lower 4.10's. I can drive 65 or less for optimal fuel economy. If I want to go faster I'll just burn a little more fuel.
 

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I like my 4:10s for everything but the interstate then they suck & I limit myself to 65. Id like to take a 355 ring or pinion & 410 ring or pinion and make something in the middle
 

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out in northern Utah its 80 mph...I need about 2 more gears in that e40d
I know right...

My buddy that lives in georgia has a 2wd version of my truck and he says he has 3.73 gears... i thought obs only came with 3.55 or 4.10...
 

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Do u have auto or stick?
 

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Discussion Starter #20
Will 315's fit a stock height truck? Will they also fit the stick 16" rim?
 
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