New tire questions

[JimCT]

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/tirete....jsp?techid=45
http://www.tirerack.com/tires/tirete...sionchart.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.