Cooper STT vs Toyo Open Country 315's

Romer · 10-12-06, 04:49 PM

I doubt the coopers would rub. My 285 BFG AT KOs have no issues and there is plenty of clearance for the additional height. It's the width I was thinking about. Now you guys got me thinking about Toyo's.

But I am just comparing the specs in the first post. I think the tread pattern is similar so the specs for weight, width and height are the differences. Height isn't a big enough delta to matter. The additional weight bothers me and I am concerned that the extra 3 inches would rub the flares at certain points. These were the points I wanted to discuss.

tarbe · 10-12-06, 05:03 PM

Quote:

Originally Posted by Romer

Thanks Mike. I'm still not sure if the the 3" additional width of the Toyo is a good thing or bad thing. It would be closer to the flares. Where is MOJ when you need him.

I just measured my 315 Toyos. 10" tread and 12.5" section (317mm), best I can measure.

I don't know where this 3" additional width of the Toyo is coming from? Ain't happening, bro

3 inches is 75MM. These would be 390's!!

These tires are very quiet. Essentially the same as my 1/3 worn BFG AT KO that Citadel just bought. They track and turn every bit as well as the smaller tire.

I can tell the difference between the 295 BFG and the 315 Toyo from a power standpoint, but I don't think that will surprise anyone.

I only have 150 miles on the tires, so my views must be taken with that in mind (except for the tread measurements....they are as accurate as a half-blind man can make them).

Oh, I should mention. They are one sweet looking tire

jamisobe · 10-12-06, 05:18 PM

Ahhh, Google. Interesting article on rotating mass:

http://forums.evolutionm.net/showthread.php?t=225495

Unsprung Weight - Part 2

By: Eric Albert

Introduction

In the first part of this series, we took a look at the effects of high unsprung weight on suspension and handeling. In this part, we will look at rotating mass. Be careful not to confuse unsprung mass with rotating mass. Reducing both is good, but they are not the same. Let's take a look.

Rotational Inertia (or Momentum)

Rotational inertia is a concept a bit more difficult to deal with than unsprung weight. Inertia can be thought of as why a car wants to keep rolling once moving, or remain in place once stopped (unless you forget to set the parking brake on that hill). I believe the terms momentum and inertia are interchangeable. The term “flywheel effect” also refers to these concepts. In a car, there are a number of rotating masses which require energy to accelerate. Up front, ignoring the internal engine components like the crankshaft, we have to worry about the flywheel, clutch assembly, gears, axles, brake rotors and wheel/tire. Out back its a little simpler (for FWD) with just the brakes and wheel/tire contributing most of the mass.

The more mass an object has, the more energy it takes to accelerate it. To accelerate a rolling object such as a wheel, you must both accelerate its mass plus overcome its rotational inertia. As for braking, you must overcome its rotational inertia plus decelerate its mass. By reducing the weight of the vehicle's rotational mass, lightweight wheels provide more responsive acceleration and braking.

Before continuing with our informal analysis here, I want to point out something very important about rotational inertia. We’ve all seen the ice skating move where the skater starts spinning. She pulls her arms in and speeds up, then extends them again and slows down. Why is this? Well, the further a mass is from the center of rotation, the faster it must travel for a given angular speed (how many degrees of an arc it traverses per time unit). The faster anything moves, the more energy it has, so when the arms are pulled in, conservation of energy says that the rotation rate must increase due to equal energy being applied to the same mass over a smaller diameter. Applying this to wheels and tires, which have most of their mass spread as far as possible from the rotation center, I think you’ll agree that it naturally takes more energy to accelerate them. Example: Take a two identical masses, but one is a solid disk of diameter D, the other is a ring of diameter 2D. The ring will require more force to accelerate it (in a rotational manner). Therefore a heavier rim with a smaller diameter could have less rotational mass than a lighter rim of a larger size, and accelerate faster with the same force applied.

The effect of rotating mass can be calculated using Moment of Inertia (MOI). MoI is related to not only the mass of the rotating object, but the distribution of that mass around the rotational center. The further from the center, the higher the MoI. The higher the MoI, the more torque required to accelerate the object. The higher the acceleration, the higher the torque required.

Because of this, the weight of rotating mass such as wheels and tires on a car have a bigger effect on acceleration than static weight such as on the chassis on a car. When purchasing new wheels and tires for a performance car, it can be useful to compare the effects of different wheel and tire combinations. This is especially true when considering upgrading to larger wheels or tires on a car.

The use of light-weight alloys in wheels reduces rotational mass. This means that less energy will be required to accelerate the wheel. Given that each pound of rotational mass lost provides an equivalent performance gain as a 10 pound reduction in vehicle weight, the benefits of light alloy wheels on vehicle performance cannot be overlooked.
For example:
***A reduction in the weight of the rim/tire assembly of 5lbs x 4 (all around the car) is equivalent to a 200lb weight reduction in vehicle weight (thats worth 0.200 in the 1/4 mile)***

So What's the Point?

The point of this discussion is as follows: There is a great deal of rotational mass to deal with in a car and tires and wheels may only make up half of it. Estimates for weight (o.k. for comparison since they’re all in the same gravity field, therefore the mass would be a similar ratio)
Front: Rear:
Wheel/tire: 30-35 lbs each 30-35 lbs each
Flywheel: 15-20 lbs
Clutch: 15 lbs
Halfshafts: 7-10 lbs each
Gears: 5-7 lbs
Rotors: 3-5 lbs 3-5 lbs
Misc: 3-5 lbs 3-5 lbs
------------------------------------------------------------------
Total: 115-148 lbs 76-90 lbs

So a couple pounds here and there on wheels and tires will make a difference, but that difference is magnified because that weight is placed further from the axis of rotation than any other mentioned (remember the ice skater). All these masses must be accelerated, so any reduction is a good thing. Now you know why we always say don't get those 18" rims for your civic. Not only are the heavier, they have a larger overall diameter. Even with lower profile tires, most plus sizing leaves us with a slightly larger wheel.

Romer · 10-12-06, 05:58 PM

Quote:

Originally Posted by tarbe

I don't know where this 3" additional width of the Toyo is coming from? Ain't happening, bro

3 inches is 75MM. These would be 390's!!

I got it here from the toy site. Does the overall width column mean something else?

Tools R Us · 10-12-06, 06:09 PM

Quote:

Originally Posted by Romer

I got it here from the toy site. Does the overall width column mean something else?

Overall or section width is measured at the widest point of the tire, most times the sidewall, it has little to do with tread width. Toyo & Nitto don't publish tread width.

NorCalSam · 10-12-06, 06:14 PM

I really don’t think that the debate is witch tire is better and why but maybe it is witch tire is better for you. I have had Toyo mts for some time now and love them. In my opinion the to are not in the same class to compare quality wise. The Toyo in a 285 is the only off road type tire with a E load rating and the sidewall is just the strongest you will find and seems to be as good or better then the Goodyear MTR in off- road performance and yet it will last longer. The Copper looks almost as close of a copy as they could do without getting into trouble. The load rating, stronger stiffer sidewall, and heavier weight are all better for off-road and safer on road for a rig that can weigh in over 7,000 lbs fully loaded.
But the much narrower width of the copper on a almost 35” tire is good to see because a lot of people have been looking for a good tire that size that have a smaller lift like a 2.5” with ½” spacers up front or J spring because the wider 35” are hitting or rubbing.
Wider Vs. Narrow
It all depends on wow you talk to I think some like narrow some like wide. Personally I would rather have more ground clearance then width however, I am starting to see the advantage in more surface area. Again having more weigh low on the rig is a good thing.

brett76 · 10-12-06, 06:17 PM

i dnot have any discussion points. just thought id say i own the cooper stt and its awesome
thats all

Romer · 10-12-06, 06:19 PM

Thanks, I edited post 1 with the widths that seem to be pretty much the same based on what Tim measured. The means that height and weight are the only deltas.

So is the 13-16 lbs additional weight per tire a nit and a non factor.

NorCalSam · 10-12-06, 06:38 PM

Quote:

Originally Posted by Romer

Thanks, I edited post 1 with the widths that seem to be pretty much the same based on what Tim measured. The means that height and weight are the only deltas.

So is the 13-16 lbs additional weight per tire a nit and a non factor.

Pro:
Better for stability more weight down low on the rig is a good thing

Con:
Harder on the truck and some loss of power to the road.

How much? Don't ask me my friend

Sam

MoJ · 10-12-06, 07:38 PM

Ken -

fwiw

I don't have any experience with the Coopers so can't say much about them.

You mention the sidewall is thicker on the Toyos - I didn't see how much - is it enough to make a difference? They're probably both great tires but if the sidewall thickness difference is significant than that would make the choice easy for me. The tread that extends down the sidewall on the Toyo's is pretty thick stuff. Just a swag but it looks like the Toyo siping might be a little better.

I've been happy with the Toyos 315's because they're very well mannered on the road and balanced out great. They don't feel any different than my 305/70 BFG A/T's did as far as handling. I did notice a power loss but it wasn't enough to concern me. If I lived in your area I'm sure I'd regear. If my 80 was my daily driver it might be more of an issue. Bet it won't be a problem with your SC. They weigh more but I figure the Japanese engineers didn't just accidently make that happen. Kind of like our heavy 80's, I assume it was necessary to achieve what was considered a superior design. I like that they're true to their sizing but it doesn't sound like that's a big issue for you. Mine measured 34 15/16th's when mounted on the rim with no weight load. Oh yeah, they're also pretty.

As far as rubbing - I have ome 2.5 medium all around with Mr G 1" up front. The rears will rub at full stuff, no denying it. At first I thought they were just rubbing on the inner flare lip and the mud flap. I trimmed a portion of the inner flare lip and the mud flap, both easy to do with a dremmel. I sanded the inner flare lip smooth with some fine paper. It takes a very close eye to tell that it's been done.

However, after all that they still rubbed. Finally figured out it was rubbing at the top of the wheel well cavity. I sorta expected that all along but wanted to avoid dropping the rear bump stops if I could. I installed Slee's 2 inch rear bump stop extensions and the problem went away. I haven't experimented yet but it may not be necessary to drop the bump stops a full 2". I'd like to play around with some shorter bump extensions and see if I can get back a portion of the rear flex that I lost when lowering the stops. It's probably not that big of a deal as I don't think anyone has ever complained about 80 series being short on rear flex. Despite trying like hell I've been unable to get the fronts to rub which amazes me.

Good Luck!

EDIT: Noticed the first post listed the Toyo load range as D. Just went and looked at the sidewall and mine are marked "LOAD RANGE E"

jamisobe · 10-12-06, 07:47 PM

Quote:

Originally Posted by Romer

Thanks, I edited post 1 with the widths that seem to be pretty much the same based on what Tim measured. The means that height and weight are the only deltas.

So is the 13-16 lbs additional weight per tire a nit and a non factor.

"Given that each pound of rotational mass lost provides an equivalent performance gain as a 10 pound reduction in vehicle weight, the benefits of light alloy wheels on vehicle performance cannot be overlooked.
For example:
***A reduction in the weight of the rim/tire assembly of 5lbs x 4 (all around the car) is equivalent to a 200lb weight reduction in vehicle weight (thats worth 0.200 in the 1/4 mile)*** "

I read somewhere else where they said every pound of weight on the wheel lost was like 8 lost from the chasis.

jamisobe · 10-12-06, 07:52 PM

The weight is a big deal for me, but I want a solid tire. I know that the Toyo is a great tire from my research, but I don't know enough about the Cooper. Luckily, I can wait for a while longer before I have jump.

jamisobe · 10-12-06, 07:54 PM

But on the other hand...

that extra 1300-1400 of tire load capacity could come in handy if I need to tow a load.

jamisobe · 10-12-06, 08:23 PM

Peterson's four wheel article:

http://home.earthlink.net/~jandastavola/cooper-stt.jpg

The web:
http://www.swindolllaw.com/news/CooperTire.htm

g8mfzj80 · 10-12-06, 09:36 PM

After seeing both these in action on the rocks, mixed dirt, desert tracks several times and talking with the owners I would take the toyos. The sidewalls are tougher and some of the baja guys I known run and rave about them.

For what I’ve seen the coopers are not nearly as sticky on rocks and you have air down more. On the higway the coopers seemed louder than say a typical AT like the BFG KO's while the toyos are about the same.

I personally think wider tires add some stability as you go higher so the toyos help in that area IMO.

Other one that looks good (same price as the coopers) but I have'nt heard too many reviews on is the MT Baja Radial MTZ

Romer · 10-13-06, 07:52 AM

You guys convinced me, I'm going with the swampers

No really the Toyo Open Country. The fact they stick on the rock a bit better, stronger sidewall and are quiet (Comparatively) on the highway. Looks like I'll be putting those L shocks I have on.

Nay · 10-13-06, 09:23 AM

If money is not the issue I don't see what the debate is about. The biggest issue with MT's this size is balancing, and the Toyos from all the reports appear to have that nailed. I bet you will like the Toyos for road use better than your BFG AT's.

You have a supercharger...so tire weight should be a non-issue. Look, I lug around 35" load range E trxus on 4.10's without forced induction, and when I went from 285 BFG AT's to 33" trxus when I first bought the rig, which is a much heavier tire, it didn't make any difference (sucked before and after). This question is splitting hairs on a rig with 35" tires.

As far as front end component wear, an unbalanced tire is going to be far more problematic than a heavier tire. That is the reason to buy the Toyos, and I would absolutely pay $25 a tire for this.

Plus, the smallish 315's are a negative in my view. The 80 can handle a true 35" tire. Go for it!

Nay

kennyv0826 · 10-13-06, 11:34 AM

I think the Toyo is your best bet even though they are both excellent tires from all accounts I've heard. I don't think the extra weight will make a big difference in the way you 80 drives. And that weight is there for a reason. It makes the tire stronger, and I think we'll all agree that is never a negative (especially off road).

Let us know how you like them. I'm gonna install some 37" Toyo's pretty soon. I'm excited!

jamisobe · 10-13-06, 02:32 PM

I am agreeing on the weight issue. The extra weight may have something to do with the Toyo being a more streetable tire as well as load capacity. Maybe when I switch my 33s to 35s I will sell my 4.88s and go for the 5.29s. That should more than compensate for the added rolling mass. I don't want to be a slug.

MoJ · 10-13-06, 02:40 PM

Quote:

Originally Posted by jamisobe

I am agreeing on the weight issue. The extra weight may have something to do with the Toyo being a more streetable tire as well as load capacity. Maybe when I switch my 33s to 35s I will sell my 4.88s and go for the 5.29s. That should more than compensate for the added rolling mass. I don't want to be a slug.

The general recommendation by many for re-gearing when going to 35's is 4.88.

jamisobe · 10-13-06, 02:44 PM

Quote:

Originally Posted by MoJ

The general recommendation by many for re-gearing when going to 35's is 4.88.

I have read that. I think it is a good way to maintain a somewhat accurate speedo. However, I have a tru-speed calibrator that makes it really easy to adjust for different gearing and size tires.

I am amazed at how quick my truck is with exhaust mods, 33s, and 4.88s

Conserving gas isn't as important to me as throttle response or acceleration on the road. Afterall, have you seen gas prices? They are all the way down to 2.20 a gallon. That's practically free!

Romer · 10-13-06, 07:19 PM

I ended up with the 315/75/R15 Toyo Open Country MT's. Even though they were siped, I had the tire dealer sipe them some more as I thought it could use a bit more. The tire guys said they were really heavy tires and two guys lifted up the spare.

Everyone was right about the highway behavior. I was concerned because driving Rachel's 4ruuner with Goodyear MTRs, I thought they might be loud. I really didn't notice the difference between them and my BFG ATKOs (Now Sarah's Tires).

I did notice a difference in the power loss. Not sure how much is attributable to the weight or the 2" larger tire.

Tomorrow, I will be installing L shocks. Since you are close to what needs to be done to swap or modify the springs, I went to visit Christo (Should try it Shotts). We put it up on his ramp and he showed me were to trim it. We talked about adding more lift (spacers/Springs). I wanted to know if it was necessary. He basically said if my plans are to wheel in the same kind of stuff I am now, then no. I do need to add bump stops and he suggested I wheel it and if where they hit the bump stops bothers me, then add lift, but otherwise leave it alone.

He said if because I have bigger tires I start to get bored and want to try harder stuff, then I should add lift. Adding a lift adds other concerns with the drive line, etc. so leave it alone if I am happy with it.

They drove great, I am real happy with them. Can't wait to wheel with them.

Note : first pick with 285's, 2nd pic with the Toyo's

jamisobe · 10-13-06, 07:34 PM

Those are some sweet lookin' feet. I've been looking around and the Toyos are seeming like the way I will eventually go even though the heavier, taller tires will sacrifice acceleration on the street. I must start thinking 5.29s, 5.29s, 5.29s.

Congratulations!

NorCalSam · 10-13-06, 08:21 PM

That looks sweet!
What lift do you have and are you now hitting or rubbing in any way?
Are you thinking of installing L shocks to a 2.5" lift? And If so let me know what you think of that wondering if the 2" of lost up travel will be missed.
later.

Congratulations on the new rubber.

Romer · 10-13-06, 08:23 PM

I have 850J's in the front and 863's in the back. With all the goodies I have, that gives me about a 3" lift. Chrsito showed me via the ramp that I will need to trim a little off the inside of the flare, you won't be able to tell. I will be putting L shocks on in the next few days.

tarbe · 10-13-06, 08:27 PM

Now you need to go back and do that black trail with the Toyos!

We are twins, once again

ps - your body man is fast!

Buckru · 10-13-06, 08:30 PM

The truck looks frikin sweet Romer. Did I miss the thread about the "Flat Nasty Passenger Side Repair"?

Buck

Hayes · 10-13-06, 09:03 PM

Those look sweet.
Your rig looks very nice.

After all this talk of 315's and MT's, and now that my 80 is no longer a daily-driver, I've been daydreaming of 4" lifts and 35" tires for the first time ever...

...it'll never fly with the wife...

Quote:

Originally Posted by Romer

I ended up with the 315/75/R15 Toyo Open Country MT's. Even though they were siped, I had the tire dealer sipe them some more as I thought it could use a bit more. The tire guys said they were really heavy tires and two guys lifted up the spare.

Everyone was right about the highway behavior. I was concerned because driving Rachel's 4ruuner with Goodyear MTRs, I thought they might be loud. I really didn't notice the difference between them and my BFG ATKOs (Now Sarah's Tires).

I did notice a difference in the power loss. Not sure how much is attributable to the weight or the 2" larger tire.

Tomorrow, I will be installing L shocks. Since you are close to what needs to be done to swap or modify the springs, I went to visit Christo (Should try it Shotts). We put it up on his ramp and he showed me were to trim it. We talked about adding more lift (spacers/Springs). I wanted to know if it was necessary. He basically said if my plans are to wheel in the same kind of stuff I am now, then no. I do need to add bump stops and he suggested I wheel it and if where they hit the bump stops bothers me, then add lift, but otherwise leave it alone.

He said if because I have bigger tires I start to get bored and want to try harder stuff, then I should add lift. Adding a lift adds other concerns with the drive line, etc. so leave it alone if I am happy with it.

They drove great, I am real happy with them. Can't wait to wheel with them.

Note : first pick with 285's, 2nd pic with the Toyo's

Romer · 10-13-06, 09:14 PM

Quote:

Originally Posted by Buckru

The truck looks frikin sweet Romer. Did I miss the thread about the "Flat Nasty Passenger Side Repair"?

Buck

http://forum.ih8mud.com/showpost.php...8&postcount=61

ginericLC · 10-13-06, 11:08 PM

Romer,

I'm running the Js with a 1" spacer in the front with the 315 Toyos. I have about 10k or so on them I'm guessing. They do get a little louder as they wear but my tire guy says at about 20k they will quiet back down. My friend with brand new Cooper STTs says my tires are quiet. I think they are acceptable for what they are.

I rub on the PS rear flare under full compression. I think if I took a 1/2" off the lip of the flare I'd be OK. I'm not running any additional bumpstops over factory. I didn't drop them at all. Front has never been an issue. I have not relocated my panhard bars. I think if I did I would have zero rubbing through the whole range.

They are heavy. I have noticed a decrease in mileage and stopping ability. I went from 315/75/16 BFG ATs that didn't even have 5k on them.

I like that they balance well. I have one with only .5 oz of weight.

Mine are chunking but that is expected for our lava rock. Other than a Swamper SXs everything pretty much chunks in our rock. I've had zero sidewall issues. I've run them as low as 10psi. Mostly I try to run about 12 psi or so on the trail. On long trips I've run them as high as 42psi. Sidewalls are a big deal here. MTRs have issues, BFGs are any easy pick in the sidewall too.

If it weren't for price I probably would not even consider another tire. For awhile they were almost $300 a pop. They've come down a little in price again. I paid $204 or 206 for mine. In Idaho, they are running right around $270 right now. At these prices I've considered going to two sets of wheels and tires. A cheap BFG AT for the highway and a Swamper Bias for the trail. Longevity wise I think I'd come out ahead with the two sets but it would be a PITA to swap all the time.

I'm happy with the dual role that they play very well. We will see how they handle this winter. If good, then I'll be conviced they are the best all around tire.