New tire questions

[JimCT]

Truxus

Truxus, 235 or 255 85x16 siped amazing in snow and off road and pretty quiet too. Jim

[Rosie]

I gotta do my tire homework.
What do all these numbers refer to?
I can google it up and find out, but if you don't mind me being lazy, and you have the info quick, I would like to know tire measurement basics.
I'm thinking to keep the 15" tires and just get the very best roadworthy tires that can also deal with mud, ice and snow.
I have looked at the reviews for all the tires mentioned here. The reviews seem the best for the Coopers.
I like the soft vs. hard rubber concept. That makes sense.
How do you know if a tire is hard or soft, by the stuff it is made of, or the way it is made?
So many questions!!!
Since I won't be putting more than 8,000 miles on the vehicle in one year, probably way less, I may have these tires for a good long time! Want to get it right the first time. Thanks so much, this is great stuff!!!!

[Blueboy]

Truxus, 235 or 255 85x16 siped amazing in snow and off road and pretty quiet too

I had a set of the 235s on my last Rangie and yes, they were like you described.

my problem with them was I couldn't keep them in balance for any length of time.

not sure if it were just this set or a common problem with them.

Rosie,

this link is pretty good for calculating outside diameter for differnet tire size configurations http://www.moparregister.com/articles/calc/


Jaime

[Eric W S]

Does either size, 15" or 16" wheel/tire have an advantage with regard to steering tightness?
My steering seems rather loose.
Right now the rover has very old, possibly original, G78-15 Suburbanites tires.

Steering issues run the gamut. Could be float in the box, loose bolts on the relay, bad tie rod ends on and on.

Get the factory manual and start reading.

EwS

[LaneRover]

I agree that if your rims are in good shape then it makes sense to stick with the 15's. I would go for a taller 15 personally.

I find that the best way to check for looseness in the steering components is to have someone sit in the truck moving the steering through its 'loose area' while you look and see what is moving. I have had both the big nut that holds the arm onto the steering box was loose as well as the arm attached to the bottom of the steering relay. Just methodically look from the steering box on down the line. If something is moving and the thing it is attached to isn't (or isn't as much) then you have found the spot! (There may be a few spots that are a bit loose) You will be surprised at how quickly you can get your steering tightened up.

Brent

[yorker]

Does either size, 15" or 16" wheel/tire have an advantage with regard to steering tightness?
My steering seems rather loose.
Right now the rover has very old, possibly original, G78-15 Suburbanites tires.

G78-15 dia:28.0" width:8.4" load rating:1,620 lbs @ 32 psi

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=45

http://www.tirerack.com/tires/tiretech/45_conversionchart.html

I think I usually see H78 15s on 88s which have 30 year old tires on them. Most people used to replace them with 235 75 15 modern tires. Those are still small by today's style standards though. Most people now seem to prefer something around a 32" diameter tire rather than the original ~28" tires (original for an 88" 109s had ~32" tires stock, 7.50 16s)

[Leslie]

Rosie,

Ok, all the numbers.....

You've got a handle on 15" or 16" wheels, that's the diameter of the wheel itself.

Used to, when most tires were bias-ply, you can think of them as having something more-or-less of a balloon cross-section, so a 6.0x16 versus a 7.5x16, would be a 6" diameter versus a 7.5" diameter for a cross-section of one side of the tire... so, for a ballpark, 7.5+7.5 (twice, for each side of the tire), +16 (for the wheel), is 31" tall versus 28" for the 6" one.

But, they don't measure them like that now, since they're mostly radials.. instead of having a round cross-section, you have a width, and a certain amount of height, for the tire section.

If you have a 235/85R16, you have a tire for a 16" wheel, the tire is 235mm wide (I've always thought it funny that we're mixing metric and english units), and then the height of the section is, 85% of the width. If you have a 235/70R16, again, you have a 16" wheel, and a tire that's 235mm wide, but the height of the section is 70% of the width.

If you go to a 215/85R16, you have a narrower tire than a 235/85R16. And, while both are 85% on 16" wheels, 85% of 235mm is a little taller than 85% of 215mm.

Hope that helps..... makes it clear as mud, eh?

[Rosie]

Man, you guys are smart!!
So now I have too much choice!!! All these different sizes!
I am pretty sure I am going to get the Cooper Discoverer S/T's and put them on the 15" wheel.
Which size will give the best overall performance on the road, for steering and general stability of the vehicle, and for appearance? Since the 15's are kind of small, should I get taller tires to make them look bigger? Wider tires for better steering? Never thought tires were this complicated!!
I sure do appreciate all this information!!!

[bearcrawl]

Is anyone running 255 85 16. Seems like a pretty nice size. I know only a couple companies make them but I run BFGs anyway.

[Leslie]

If you're going to stick with the 15" wheels, and you've decided on the Discoverer S/T, I think your best choice is their 235/75R15 (I think it's that tire's only reasonable size for a Series Rover... I'd try to go a bit narrower and taller, but there's not one... they have a 205 width, but it's only a 70 series).

FWIW, in a 75 Series tire, for a 15" wheel, if you go with a 215 width, BFG's are available in both A/T and M/T... I like the idea of narrow for a Series. However, that 235/75R15 is a common size. You can find BFG's M/T and A/T, Dunlop's Radial Rover R/T (and the Mud Rover, but I like the R/T better), that Cooper Discoverer, several Kumho's, General's Grabber.....).

Remember: for *any* car/truck, no matter the engine or suspension or interior or anything else about it, all of its performance revolves around the relationship between the tire and the road.... those four little contact patches are what controls your vehicle's behavior.

[Leslie]

Is anyone running 255 85 16. Seems like a pretty nice size. I know only a couple companies make them but I run BFGs anyway.

A buddy of mine is running them on his Disco... had to do a good bit of work (replacing trailing arms, cutting out of body-work, etc.), but he's happy with them.

On a Series, would be easier to fit, but, if you've got a tired 2.25 churnin' it all along, that's a lot of weight....

[Rosie]

Leslie,
So basically you are saying that if I got the BFG A/T or M/T I could get a better fit for the 15" wheels, than with the Cooper tire?

[Leslie]

Well, it depends on what you want..... a 'better' fit for you might not be a better fit for me.

They're all available in 235/75R15 (looking at TireRack, just to get a comparison of available tires for a given size). For a ballpark, that's going to be about a 29" tall tire.

BFG gives you the option of going down to a 215/75R15, which will end up being a bit under 28" tall, so it'll be a bit shorter, but the tire will be about a half-inch narrower.

The end effect, all else being the same, is that the truck would feel like it'd accelerate a little quicker, it'd be a little easier to steer, but it'd lose a half-inch in ground clearance.

Also, considering price: Again, basing it on TireRack, and using the BFG A/T as a common comparison, if you go with the 235/75R15 it's listed at $117/tire, but the 215/75R15 is $104.

I've not used the Cooper, I can't personally vouch for it, but I've not heard anything bad about them, either. I did like the BFG A/T on our Disco, but, I liked the Dunlop R/T a bit better, but it's harder to find for the same price, depending on the size ( it is usually a bit more, but, is a little less at TireRack at the moment). The BFG M/T is gonna be even more than the A/T, but, would have a more aggressive look, still be fine on the street, etc.

If you like the Cooper, you're gonna go w/ the 235/75R15 size.... and can go with that size for the BFG too.... or, narrower/a little shorter, too.

Depends on what you want it to feel like driving. If you don't mind the wheel being a little more difficult to pull on, you might prefer the 235 width, as it'll give you a little more clearance, and a lot more selection (like adding in the Dunlop R/T as a possibility). But, if you've been driving your Series around a bit, and aren't overly thrilled with how much effort to steer is required, and don't have to have that extra 1/2" of ground clearance, you could go w/ the 215 width in the BFG's...

Some things for you to mull over.....

[Rosie]

Thanks Leslie,
That clears things up a bit more.
The reason I was going to get the Coopers is because they seem to have a better review for traction in snow than the BFG.
Whether that is true or not, I don't know, it is a review written by the company, so who knows.
Experience will know!!
At this point I am not really looking so much at price, because in the end, spending a few more bucks, in my experience, is worth it if the quality is better. You have to live with the choice, and over time, a few dollars here and there won't matter.

[Blueboy]

If you don't mind the wheel being a little more difficult to pull on, you might prefer the 235 width

Blueboy has 235/85 and Leslie is spot on for the difficulty in turning the steering wheel when say parking or slow speed manuevering.

If there is going to be a lot of steering turns I usually end up going to low range so I can have some movement when making the turns.

Don't get me wrong, its not that hard, yet, you will notice that you're using some muscles!

And you're definatley right in getting what you want even if a little more in price as your choice will last for years - I'm on 7 now with the TracEdges and am more concerned with the rubber cracking than wear.

It has been said a few times, yet, sipes are your friend for snow and rain performance.

You really can't go wrong (imho) with any of the brands you're considering.

Jaime