aggressive looking 4 or 6 ply???

polock · **Posted:** Sat Mar 15, 2008 2:06 am

ok i have settled on the 235/85/16 for the size, i now what to find a tire that is really aggressive looking but in a lighter weight tire for gas mileage improvement over a 10 ply... main thing i am looking for is a good looking side wall. i was wanting to go with cooper discovery sst's but they look really heavy, and since i am not going to be trail riding much i can go much lighter on the ply

Fulltimer · **Posted:** Sat Mar 15, 2008 4:01 am

Go to www.tirerack.com and take a look around. They have the tire weights listed under "specs".

Terry

moose · **Posted:** Sat Mar 15, 2008 7:55 am

polock wrote:

ok i have settled on the 235/85/16 for the size, i now what to find a tire that is really aggressive looking but in a lighter weight tire for gas mileage improvement over a 10 ply... main thing i am looking for is a good looking side wall. i was wanting to go with cooper discovery sst's but they look really heavy, and since i am not going to be trail riding much i can go much lighter on the ply

Since this is a commercial tire size, you have to look to just find a "D". You may want to consider the 245/75, as those can be had in a "C", such as http://www.tireboy.com/dayton_timberline_at_tire.htm

jason thompson · **Posted:** Sat Mar 15, 2008 11:37 am

polock wrote:

ok i have settled on the 235/85/16 for the size, i now what to find a tire that is really aggressive looking but in a lighter weight tire for gas mileage improvement over a 10 ply... main thing i am looking for is a good looking side wall. i was wanting to go with cooper discovery sst's but they look really heavy, and since i am not going to be trail riding much i can go much lighter on the ply

You will probably not find a C load in that size
also tire weight matters VERY little as far as MPG
The thing that hurts MPG the most is a change in over all gearing ,taller tires make the over all gearing taller
taller gears means less rpm but the engine is still doing the same job so it burns more gas

stock tire hight or with in .5" their of will give the best MPG any taller and the MPG's will melt away

onejohny · **Posted:** Sat Mar 15, 2008 12:08 pm

jason thompson wrote:

polock wrote:

ok i have settled on the 235/85/16 for the size, i now what to find a tire that is really aggressive looking but in a lighter weight tire for gas mileage improvement over a 10 ply... main thing i am looking for is a good looking side wall. i was wanting to go with cooper discovery sst's but they look really heavy, and since i am not going to be trail riding much i can go much lighter on the ply

You will probably not find a C load in that size
also tire weight matters VERY little as far as MPG
The thing that hurts MPG the most is a change in over all gearing ,taller tires make the over all gearing taller
taller gears means less rpm but the engine is still doing the same job so it burns more gas

stock tire hight or with in .5" their of will give the best MPG any taller and the MPG's will melt away

Taller gearing should give you better fuel economy. It's like having a lower final drive ratio. I don't know hor this screws up the MPG calculation though as your odometer/speedometer would also be off.

InCommando · **Posted:** Sat Mar 15, 2008 12:24 pm

There are plenty of online calculators to figure out your odometer descrepency, or a decent gps works.

I honestsly think that any gains made by changing the final drive ratio would at least be negated by the additional weight of the tires & wind resistence changes. Many people swear that the biggest effect on mileage and performance is in increase in "unsprung" weight and that lighter brakes/wheels/tires are major factors. The standard in raacing is the 10/1 factor. 10#'s added in unsprung weight is equal to 100#'s added elsewhere. Althought this added weight can be great for improving traction, it probably does effect performance and economy. Besides being cheap a$$es, this is one reason why most brake rotors have become thinner/lighter and alloy wheel are preferred over the stronger/cheaper steel versions.

jason thompson · **Posted:** Sat Mar 15, 2008 4:40 pm

onejohny wrote:

jason thompson wrote:

polock wrote:

ok i have settled on the 235/85/16 for the size, i now what to find a tire that is really aggressive looking but in a lighter weight tire for gas mileage improvement over a 10 ply... main thing i am looking for is a good looking side wall. i was wanting to go with cooper discovery sst's but they look really heavy, and since i am not going to be trail riding much i can go much lighter on the ply

You will probably not find a C load in that size
also tire weight matters VERY little as far as MPG
The thing that hurts MPG the most is a change in over all gearing ,taller tires make the over all gearing taller
taller gears means less rpm but the engine is still doing the same job so it burns more gas

stock tire hight or with in .5" their of will give the best MPG any taller and the MPG's will melt away

Taller gearing should give you better fuel economy. It's like having a lower final drive ratio. I don't know hor this screws up the MPG calculation though as your odometer/speedometer would also be off.

not true
when they engineer almost any car the #1 concern is MPG and how to get the best and what works the best
the KJ gets the best mpg with a ~29" tall tire no lift over stock and ~4200# of weight
change any of those and you change MPG
now I know that others think I talk out my butt and just the fact that I said it they will argue
how ever after 15+ years of off road experience with 3 jeeps and 1 pick up truck not to mention how many others I have talked to I would think I know a little about what happens when you modify you jeep
That being said 100% of the people who lift their (enter what you want here) and put larger tires on complain about poor MPG then all they do to get it back is regear to as close to stock as they can and most times if they lost say 5 mpg
when they regear they get 3-4 back
now unless my math is off if they get back 3-4 MPG when they lost 5 that is getting back 60-80% of the lost
60-80% is more than 50% so that would be MOST of the loss gained back

Now we know that gearing back to stock gives you back most of your loss due to taller tires the other 20-40% of loss is from rolling resistance of the larger tires and the change in wind resistance by making it higher off the ground as well pushing the wider tires through the air

Now I am not an expert but who really is?
I can give you the numbers to 4 local 4X4 shops and I can promise you that they will all tell you that if you put on larger tires you will change your final gearing and thus loose MPG regear to stock and you will gain it back

If the taller final drive really would give you better MPG then I would have gained MPG in the 4 rigs I own/owned
my brothers would have gained MPG in their rigs and about 95% of the people who I wheel with would have gained MPG
when they put larger tires on their rigs but THEY ALL LOST MPG and EVERY ONE who did a regear got MOST of it back

tjkj2002 · **Posted:** Sat Mar 15, 2008 7:58 pm

Quote:

If the taller final drive really would give you better MPG then I would have gained MPG in the 4 rigs I own/owned
my brothers would have gained MPG in their rigs and about 95% of the people who I wheel with would have gained MPG
when they put larger tires on their rigs but THEY ALL LOST MPG and EVERY ONE who did a regear got MOST of it back

^^^^^Agreed^^^^^

The key factor in going to a taller tire,or over-inflating your stock tires, is you either need to regear or(for certian vehines only) be able to produce enough low end torque to be able to turn the bigger tires(mostly only applies to larger deisels only).

dloc_jeep_KJ · **Posted:** Sun Mar 16, 2008 4:19 am

yes rear gear to around 4.10s and you will get most of ur MPG back with a 245/75/16. after i put my 245/75/16 10ply tires on the KJ i lost a ton of gas millage. more so than the lift or rack combined or even all the extra weight i have added to the thing. with all the hills where i live this hurts me even more. i plan to have the KJ regeard to 4.10 by the end of the summer to gain back some of my MPG. if you are worried about ur MPG this is the best way to get it back and yes if you put a larger tires on ur KJ(or anything) you will lose gas mileage. FYI i lost around 5 MPG from my tires (MT/Rs)

jason thompson · **Posted:** Sun Mar 16, 2008 10:31 am

dloc_jeep_KJ wrote:

yes rear gear to around 4.10s and you will get most of ur MPG back with a 245/75/16. after i put my 245/75/16 10ply tires on the KJ i lost a ton of gas millage. more so than the lift or rack combined or even all the extra weight i have added to the thing. with all the hills where i live this hurts me even more. i plan to have the KJ regeard to 4.10 by the end of the summer to gain back some of my MPG. if you are worried about ur MPG this is the best way to get it back and yes if you put a larger tires on ur KJ(or anything) you will lose gas mileage. FYI i lost around 5 MPG from my tires (MT/Rs)

did you account for the error in the speed O
remember that it was set for 29" tall tires not 30.5" tall tires
so you will travel further then what it says
I found ours to be off by nearly 7-10%

KJ04 · **Posted:** Sun Mar 16, 2008 10:37 am

The 235/85/16 is a basic tire replacement for pick-ups with dual rear tires and come with a standard E-10 ply rating.

dloc_jeep_KJ · **Posted:** Sun Mar 16, 2008 11:05 am

jason thompson wrote:

dloc_jeep_KJ wrote:

yes rear gear to around 4.10s and you will get most of ur MPG back with a 245/75/16. after i put my 245/75/16 10ply tires on the KJ i lost a ton of gas millage. more so than the lift or rack combined or even all the extra weight i have added to the thing. with all the hills where i live this hurts me even more. i plan to have the KJ regeard to 4.10 by the end of the summer to gain back some of my MPG. if you are worried about ur MPG this is the best way to get it back and yes if you put a larger tires on ur KJ(or anything) you will lose gas mileage. FYI i lost around 5 MPG from my tires (MT/Rs)

did you account for the error in the speed O
remember that it was set for 29" tall tires not 30.5" tall tires
so you will travel further then what it says
I found ours to be off by nearly 7-10%

yes i did it is off by around 3 mph at 60 mph

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

4.10 gears do not affect the speedo. Different diameter tires definately do though. I seem to have taken a rather large drop in fuel economy by going to the 245/75R16 6 ply load c's from the 245/65R17 passenger tires. I'm not sure how much of it is larger diameter, how much is heavier weight, and how much is from winter mix gas and letting it warm up longer. Once we get switched back off the winter mix, I hope it goes up a few mpg like it usually does. I just cleaned the throttle body, changed the plugs, ran some injector cleaner through it, and changed the air filter. If it doesn't go back up some, I'm definately going to have to get a 2nd vehicle with much better milage. Averaging 10 mpg in town hurts when the Jeep likes 93 at $3.49 per gallon.

The easiest way to adjust the speedo is to go over to the dealership and have the tech read the computer to see how many rotations per mile it is set for. Check your tire pressure, and get out on the highway and set the cruise at 60 mph and use your GPS to see your actual speed. Then pull over, do a little math, and have the tech adjust the RPM setting. Check it at 60 mph again, and make another adjustment if you're not close enough.

polock · **Posted:** Mon Mar 17, 2008 12:25 pm

i think i like the kumho road venture A/T'S they are getting great reviews and are lighter than a lot of the others. now

the size i am wanting is 235/85/16 weights 44lbs

the 245/75/16 weights 34lb's

will there be a big gas mileage difference in the 2??? that will also help me with my decision

KJ04 · **Posted:** Mon Mar 17, 2008 1:22 pm

polock wrote:

i think i like the kumho road venture A/T'S they are getting great reviews and are lighter than a lot of the others. now

the size i am wanting is 235/85/16 weights 44lbs

the 245/75/16 weights 34lb's

will there be a big gas mileage difference in the 2??? that will also help me with my decision

You will get far better milage with the 245/75/16 and less rubbing.

aggressive looking 4 or 6 ply???

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