Help with Tire Question

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Mar 28, 2005 | 09:03 AM

fish4bass

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From: TN

Help with Tire Question

I have been running stock 265's and speedo shows about 3 mph faster than actual speed. Tires are currently stock BFG Rugged Trail (stock). I have heard that if you go up to 285's the speedo is about right and the look is better. I am looking at Michelin LTS/MS.

Sure would appreciate any comments.

Mar 28, 2005 | 11:25 AM

Crash687

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From: MI

Quote:

Originally Posted by fish4bass

check you factory speedo with a GPS. most facorty speedos are +/- 2 mph across the scale (that will change slightly depending on speed) and a jump from 265 to 285 will only change your about 2.2 mph and add about an inch to your diameter.

Mar 28, 2005 | 11:43 AM

tristankc

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From: Second star to the right!

Both of my SuperDuties were 2-2.5 mph off (depending on speed), running on the factory tires. Putting 285's on corrected the speedo on both vehicles. I have checked both against a GPS and the portable radar/speed signs. Beware though, when you switch expect to see about a 1 mile per gallon drop in fuel economy. Doing the math, the speedo correction alone drops (or should I say, fixes) the mpg 0.7. The bigger tires are good for the other 0.3 mpg. Both of mine got 0.9 mpg less when I went to 285's. So really, you are only losing a couple of tenths of fuel economy, but it look like a lot more when you calculate it out each time you fill up. I personally think that is main reason the speedo is off to begin with, to inflate the fuel economy.

Mar 28, 2005 | 12:14 PM

psmith338

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From: Parrish, FL

Mine was about 2 mph off (faster than speedo) at 65mph with stock tires. I went to 305's (Goodyear AT/S's) and it is now about 2 mph slow at 65mph. (Speedo says 65mph, my {cop} friend's radar shows 63.

However, keep in mind, it's a ratio. The faster you go, the more the spread.

Also, you'll find significant differences in actual measurements from one manufacturer to another. I don't remember the exact numbers, but I measured the circumference of my 305's the day I bought 'em & then measured a friend's tires (same "size", different brand)(his had about 500 miles on them) and found that there was a difference of about an inch...

Mar 28, 2005 | 12:24 PM

rstokes

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From: Birmingham, AL

When running the original BFG 265's my speedometer was about 2 mph fast. After changing to Bridgestone Revo 285's it is dead accurate as checked by stopwatch/mile markers and with GPS. This switch also seemed to change my mpg slightly for the worse but I haven't proven if this is true and by how much. The 285's certainly look better to me. Make sure you realize that when you switch to 285's from 265's, you will probably be switching from load range E to load range D. I don't know if this would affect what you might load the truck with or not in your particular case. Good Luck!

Mar 28, 2005 | 10:40 PM

fish4bass

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From: TN

Thanks gentlemen. Tristankc, do the tires actually hurt milage or just change what shows on the overhead? Several of you mentioned going to 285's...does anyone run Michelins? Again, thanks for input.

Mar 28, 2005 | 11:23 PM

Rescue Ram

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Joined: Jan 2004

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From: Lookout Mountain, CO

The last set of tires on my dually were LTX M/S. I rotated and balanced every 6k and was able to get 94,000 miles out of them (A mixture of towing 9-10k lbs on highway and off-road use). I have since switched to XPS Traction's, because they are made of a heavier rubber compound, and will hopefully last longer.

I have the LTX M/S on my 3/4 ton. They have right around 35k miles on them and are at 12/32 depth. The sidewalls are a bit squishy with a payload. Snow and mud traction is very good. Overall, an excellent choice, IMHO.