Wanting to switch to 285/75R16 or 255/85R16???

[TBarrett]

My 285's

I have 285's from 265's on my late 01. Its an auto 3. 55 quad short 24v diesel of course. Came with 265's on 16x8 alum rims. The 285's were within 1/2" taller and wider. On the auto I noticed a 200 to 300 lower rpm @ 65 and the shift patern was alittle diff too. I still am below 3000 miles on truck still. It starts alittle slower for the stop to rolling and the driving and turning is alittle heavier. Generally comes on alittle slower. I had just got to 19. 7 mpg @ 1700 miles and changed tires, then went to 18. 5. I have determined its because the increase tire size threw the actual speedo mile off @ about 1 1/2 mph slower @ 65. I havent put any box or whatever in for the computer because I have the extended warrenty to 100,000 for everything and dont want to void it. Im happy just the way my truck is. What gets me, I can light up the back tires at any time. Is that power or what!!!!!. Oh, I have a friend that did the 245 to 285 on a 1996 and he lost 3 to 4 mpg. He did have on 6" rims and rounded the tires alittle. Also, for the ride, I have the tow and camper pk on mine. I run 60 front and 40 rear psi cold, the ride is so nice. My rims on the 285's are after market with 4" to 4" off set or 0 offset for 8" rims and the trucks stance is 5"s wider too. Hope this helps you.

 

[Bigramguy]

We have several trucks,which all run 285\75\R16 BFG M\T's,with the 3. 54's. You will lose a little bottom end,but the cruise RPM is a little lower on the highway. I found this was the perfect combo,as it gets a little better fuel economy,and got rid of the exhaust drone in the cab,for the speed I usually cruise at. You will have no problems running on the stock rims. I actually prefer it,as when off-road,or plowing,it gives you more protection against damaging the rim,because the tire will hit the obstacle first. I have noticed no signifigant centre wear using the narrower rims,even with 80 PSI in the tires at all times. BFG MT's are an awesome tire.

 

[TRodney]

Thanks for all of the input!!



It looks like the 285/75R16 is the tire to buy if you want a larger diameter.



Thanks,

Tim

 

[drawson]

255s

I actially got better milage running these at higher speeds 80+. I was also able to change the speed o gear and get the speed o right on the money.



It has been my experience the the type of tire effects milage also. Big mudder types are moving alot of air as they roll. The best milage should come from rib type tires.

 

[RON'S RAM]

I have 285 75 R 16's on the stock steel rims. My mileage has changed, but I believe the odometer is off with these tires, so I'm not sure how accurate the mileage is. I document every fillup with dates and mileage. That's in the truck now, but I know with the stock tires, I could go around 500 miles before re fueling, now it's a little over 400 miles. Best I've gotten with stock tires was around 21MPG, Best with new tires is around 18 MPG. I bought Cooper all season radials. They're wearing kinda even, but they're wearing too fast for me. I've heard talk of Michelin's holding up well on our trucks, but I haven't seen an all season tire from them yet. Hope your not more confused. The bigger tires definately make the truck look better.

Ron

 

[Dave MacArthur]

Ryan-



Yes they do have a 60K warranty. I bought mine from NTB. I will find the receipt tomorrow and double check. I'll let you know. I really like these tires and they look great. I think 255/85 is the perfect size. They give the the truck more of a "military" or "industrial" look. After all, I don't think we can float our front ends (weight) over mud or snow so it's best to be able to dig down and not have as much resistence. I've been very impressed with the traction in snow, mud and rain. Much improved over the stock Michelins.



Dave.

 

[Cooker]

Thanks Dave.



I have had my eye on a set of the RV's (255/85) for quite some time now, but these damn little (245/75) Michelins I have on here now just won't wear out.



-Ryan

 

[Swamp Donkey]

I will give you some of my experiences.



Stock tires and rims for about 1000 miles. Put on Dunlop mud rover 285/75/16. After about 5,000 miles I noticed I was getting quite bad wear in the center of the tires. This is on the stock chrome rims. Checked my air pressure and they were 65 or something crazy like that. I lowered my air pressure in the rear to around 35-40 and always kept my front's at around 50 psi and never had any problems again with them wearing in the middle. I do believe that because I run quite low air pressure compared to some that this additional drag does decrease my mileage. I would think at least 1-1. 5 mpg. The Dunlop Mud rovers ended up lasting my 20,000 miles. Kelly Safari MSR 285/75/16's lasted me about 40,000 miles and I am currently running Bridgestone Duelers M/T 285/75/16 on Eagle 16 x 8 rims. This is a nice set-up IMHO. I have never went back to the stock 245/75/16's So I can't say how much my mileage was effected. But I firmly believe something is causing me to burn fuel because the best I ever see is about 15 with mostly highway miles.

 

[Dave MacArthur]

Ryan-

I had the same problem. My OEM Michelins were still in great shape at 47K miles. I always check the pressure and rotate. I finally just changed them anyway!

 

[Posm]

I switched from 245/75 to 235/85. I can tell that I have less take off power and the milage was not helped. I adjust my milage by 5. 03 percent as this is the amount that I am off when I check it against the mile marker posts. With the stock tires I was right on with the mile markers. If I had 4. 10s I would go to bigger tires. With my 3. 54s I will probably go back to stock tires when I replace again. I got 56K out of my stock Mich A/S tires and expect 70K out of my Mich. M/S tires.

 

[Kingram]

Calculations

Someone else above may have mentioned this, but thought I'd stress it again.



Once you change out the tires to larger ones, your speedo/odo won't be correct any more unless you reprogram. If you put on larger tires, you are actually traveling further than your odo shows. Thus, you "appear" to get worse mileage because you are going more miles down the road (the taller tire turns less revs per mile) than your odo thinks. So the only way to really know your mileage difference is to use a conversion factor based on past/present tire size.



Make sense?



This had me confused for a while... .



Chris

 

[bubba_zanetti]

OK,



along this line of thinking... what is the largest tire that will fit in the stock spare tire location.



I have 265s right now, but I need something that fits the wheel wells better, probably 285s, (the 295s and 305s are tempting)



Thanks.

 

[MCummings]

Re: Calculations

Originally posted by Kingram



Once you change out the tires to larger ones, your speedo/odo won't be correct any more unless you reprogram. If you put on larger tires, you are actually traveling further than your odo shows.



Chris

This is also known as "The Poor Man's Extended Warrenty. "

If your Speedo is off 1 MPH for every 10 MPH aprroximately.



If at 10,000 miles, your truck would have gone about 11,000 miles. at 100,000 miles your truck would have gone 10K more than indicated.



MerrickNJr

 

[Chipstien]

315 75/16

I have 315's on the stock rims and love them. Have 25 k's on them and still no uneven wear. I got the 4. 10 specifically for the reason that I would put this size on. Mileage is the same and only a slight rub at full turn left only.

 

[BK]

Chipstien ... .

Arent your stock rims are 8"?



I know 99 and younger were 6. 5" , it was either '00 or '01 DC finally got smart and widen the stock rims.

 

[Chipstien]

You may be right for I haven't checked them and am not really sure. Maybe I should go out and see.

 

[bubba_zanetti]

Any of you big tire guys (285/295/305) use the stock spare tire location with a big tire spare?

 

[DieselDoghouse]

Early this summer I switched to 16 x 8 ARC Baja rims and 285 BFG's. One of the smartest tings I did. MPG's is essentially unaffected!! Why? who knows!! Bigger footprint and larger rubber should drop MPG, BUT... Lighter rim and dropping rpm's (by about 200 at 65 MPH) should raise MPG, so... What I got was a better ride (lower pressure tires??) on a greater load capacity (by almost 300 lbs/tire) with hopefully longer life (more rubber) and much better handling especially on rough roads. Quick word on speedo error - I went with the Truspeed unit in case I wanted to retro-fit smaller tires (switchable ranges), but there are several units on the market. Since I am severely allergic to Scotchlock-type connectors I used automotive type Duetsch connectors all the way (see you MSD dealer). No ABS lights, wagging speedo, etc. Per police radar and GPS speedo correct to 0. 25 MPH.