Not your average "Who makes the best AT?" thread. This is an above average one! - Page 16 - JeepForum.com

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post #226 of 1245 Old 09-18-2013, 12:54 AM
Concolour
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Quote:
Originally Posted by Charley3


I don't like 31 x 10.5 R15C on XJ because they stick out to much (IMO), are harder to fit (tend to rub during turns with stock wheels), and I prefer the contact pressure of a 9.5" wide tire.
Contact pressure? Why would you care about something that has less of an impact on traction than surface area? The size of the contact patch will have more of an effect on how much grip you have than how much pressure is on it, that's why we air down. And before someone goes "well winter tires are narrower so ha!" Winter tires are narrow to cut through the snow and get to the road beneath instead of floating on top of the white stuff.

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post #227 of 1245 Old 09-18-2013, 05:58 AM
WXman
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Originally Posted by Concolour View Post
Contact pressure? Why would you care about something that has less of an impact on traction than surface area? The size of the contact patch will have more of an effect on how much grip you have than how much pressure is on it, that's why we air down. And before someone goes "well winter tires are narrower so ha!" Winter tires are narrow to cut through the snow and get to the road beneath instead of floating on top of the white stuff.
I'm not sure I agree with this. Tires work on the principle of friction. That's why there is no tire that works on sheet ice. But regardless of the surface, tires work based upon friction. If you increase pressure, you're increasing friction.

Surface area is important, but it's only part of the equation.

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post #228 of 1245 Old 09-18-2013, 06:47 AM
Concolour
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Quote:
Originally Posted by WXman

I'm not sure I agree with this. Tires work on the principle of friction. That's why there is no tire that works on sheet ice. But regardless of the surface, tires work based upon friction. If you increase pressure, you're increasing friction.

Surface area is important, but it's only part of the equation.
You increase surface area you increase friction more. Hence drag slicks
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post #229 of 1245 Old 09-18-2013, 10:27 AM Thread Starter
Charley3
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Originally Posted by Concolour View Post
You increase surface area you increase friction more. Hence drag slicks
It depends on the type of surface. Wider is better at some things. Narrower is better at some things. For my things I do narrower is better.

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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post #230 of 1245 Old 09-18-2013, 11:00 AM Thread Starter
Charley3
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Originally Posted by Concolour View Post
Contact pressure? Why would you care about something that has less of an impact on traction than surface area? The size of the contact patch will have more of an effect on how much grip you have than how much pressure is on it, that's why we air down.
What's best depends on conditions and terrain. For my needs narrower is better.

Also, one reason people air down (whether they know it or not) is to get the outer lugs to contact the ground more. Narrow tires already do that more at normal street pressure (have flatter contact patch at street pressure), which is part of why I don't need to air them down for Winter roads or moderate off roading. I only need to air down for extreme stuff.

Narrower certainly is better for gas mileage too.

Quote:
Originally Posted by Concolour View Post
And before someone goes "well winter tires are narrower so ha!" Winter tires are narrow to cut through the snow and get to the road beneath instead of floating on top of the white stuff.
You just perfectly described how more contact pressure from a narrow tire helps in Winter. In the same way it reduces or prevents hydroplaning at high speeds on wet highways (very wet with puddles like we have here).

===

Also, narrow tires are lighter (if comparing same brand, model, rim size, and load rating).

===

I like that narrow tires don't stick out as much and offer more clearance to sway bar and LCAs during turns.

===

In my prior post I didn't say narrow is better. I said I prefer them (for my needs).

In this post I didn't say narrower is better. I said narrow is better at some things, which are the things I care about most. Wider is better for some things. For some things it makes no difference which.

For example, a 31 x 10.5 R15 (or any 10.5) would improve my sand and beach abilities due to less contact pressure (more surface area) helping me float on top of sand, but a 31 x 9.5 R16C (245/75R16C) would improve my Winter road abilities due to more contact pressure (less surface area) helping me sink down and cut through snow to grab pavement.

Winter traction is more important to me than playing in the sand. That's just one example of why I prefer narrow. I could give many other legitimate reasons, but don't want to type more.

There are legitimate reasons why some guys prefer wider tires for their conditions and priorities. I'm not attacking their choice.

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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post #231 of 1245 Old 09-18-2013, 11:45 AM
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Originally Posted by Concolour View Post
You increase surface area you increase friction more. Hence drag slicks
True, but if you push down on the tire more, you increase friction also. Hence military vehicles having bicycle-thin tires on them since the beginning of time.

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post #232 of 1245 Old 09-18-2013, 12:30 PM Thread Starter
Charley3
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Originally Posted by WXman View Post
True, but if you push down on the tire more, you increase friction also. Hence military vehicles having bicycle-thin tires on them since the beginning of time.
Yes, preferred narrow tires before sand became their primary concern.

I've been told their tires have become wider for sand (since we're always in MidEast for a couple decades now).

Before sand became their priority, their tires were narrow.

Narrow is better for many things, but wide is better for desert (sand and rocks).

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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post #233 of 1245 Old 09-18-2013, 12:44 PM Thread Starter
Charley3
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I don't claim narrow or wide is better. Just different.

At some things narrow is best.

At some things wide is best.

Medium is best at some things (mud IMO).

At some things width doesn't matter.

The question is what is best for your needs?

For my needs I prefer tires that are on the borderline between narrow and medium. I prefer 9.5 to 10" (245 to 255 mm) width tires.

That's my preference. You may have a different preference. It's OK if we have different needs and preferences.

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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post #234 of 1245 Old 09-18-2013, 05:46 PM
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Ok so someone settle this for me....I've had a discussion at work with a guy about this for a while. Which is better in sugar sand? Thinner tires or wider tires? I've always held that a wider A/T is better in the soft deep silty type sand around where I live than a thinner tire. Now I know that wide mudders are useless in this kind of sand from experience as a meter reader when I was younger, but I had some pretty wide BFG ATKOs in my old 2wd chevy work truck and I took that through the same type of sand and have never gotten stuck....I don't have much experience with the thinner tires because I've never used them.

To me it seems that the BFG ATs allowed me to steer better on the sand and didn't shovel up boatloads on the back wheels.....I once drove a friends old, OLD jeep at his grandfather's place and I remember that yeah it went through the sand allright but holy jeez it was hard to steer and it had those really skinny army type tires that those old jeeps use.

So fill me in on the details would ya? LOL I'm tire stupid..
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post #235 of 1245 Old 09-18-2013, 05:57 PM Thread Starter
Charley3
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Originally Posted by JeepNowski View Post
Ok so someone settle this for me....I've had a discussion at work with a guy about this for a while. Which is better in sugar sand? Thinner tires or wider tires? I've always held that a wider A/T is better in the soft deep silty type sand around where I live than a thinner tire. Now I know that wide mudders are useless in this kind of sand from experience as a meter reader when I was younger, but I had some pretty wide BFG ATKOs in my old 2wd chevy work truck and I took that through the same type of sand and have never gotten stuck....I don't have much experience with the thinner tires because I've never used them.

To me it seems that the BFG ATs allowed me to steer better on the sand and didn't shovel up boatloads on the back wheels.....I once drove a friends old, OLD jeep at his grandfather's place and I remember that yeah it went through the sand allright but holy jeez it was hard to steer and it had those really skinny army type tires that those old jeeps use.

So fill me in on the details would ya? LOL I'm tire stupid..
I've owned narrow, wide, medium, and now borderline between narrow and medium tires.

Wider tires are better on sand than narrow tires. No doubt about it. AT are better on sand than MT.

BFG AT was made for the desert. So of course it's good on sand (especially in wider sizes).

That old Jeep you mentioned probably didn't have power steering. So of course it's hard to steer, especially on sand, but that would probably be true with any width tire.

A narrow tire has just as much advantage on Winter roads as a wide tire has on sand. The question is, what is your priority?

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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post #236 of 1245 Old 09-18-2013, 06:29 PM
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Quote:
Originally Posted by JeepNowski View Post
Ok so someone settle this for me....I've had a discussion at work with a guy about this for a while. Which is better in sugar sand? Thinner tires or wider tires? I've always held that a wider A/T is better in the soft deep silty type sand around where I live than a thinner tire. Now I know that wide mudders are useless in this kind of sand from experience as a meter reader when I was younger, but I had some pretty wide BFG ATKOs in my old 2wd chevy work truck and I took that through the same type of sand and have never gotten stuck....I don't have much experience with the thinner tires because I've never used them.

To me it seems that the BFG ATs allowed me to steer better on the sand and didn't shovel up boatloads on the back wheels.....I once drove a friends old, OLD jeep at his grandfather's place and I remember that yeah it went through the sand allright but holy jeez it was hard to steer and it had those really skinny army type tires that those old jeeps use.

So fill me in on the details would ya? LOL I'm tire stupid..
bald hiway treads , drag slicks , or sand paddles are best for sand
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post #237 of 1245 Old 09-18-2013, 08:16 PM Thread Starter
Charley3
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Originally Posted by 970001zj View Post
bald hiway treads , drag slicks , or sand paddles are best for sand
Agreed. Especially in wider sizes.

Highway tires and all season tires are good on sand, and they have other uses too.

However, All Terrain tires are good enough on sand, and they have many other uses too.

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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post #238 of 1245 Old 09-19-2013, 09:17 AM
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Originally Posted by WXman View Post
True, but if you push down on the tire more, you increase friction also. Hence military vehicles having bicycle-thin tires on them since the beginning of time.
Let's see every Military Tactical Vehicle in the last 20 years has had wide tires.They upgraded the old 5 ton series trucks from duals(thin tires) to wide super singles long ago.Even the HMMWV's use 12.50" wide tires,which is the thinnest tires used by the military now as most are 16" to 18" wide.

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post #239 of 1245 Old 09-19-2013, 11:40 AM
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Originally Posted by tjkj2002 View Post
Let's see every Military Tactical Vehicle in the last 20 years has had wide tires.They upgraded the old 5 ton series trucks from duals(thin tires) to wide super singles long ago.Even the HMMWV's use 12.50" wide tires,which is the thinnest tires used by the military now as most are 16" to 18" wide.
Aren't HMMWV tires 37s? 12.50 width is thin for a 37. And the other vehicles you mention are increasingly larger and heavier and have taller and taller tires now days. You didn't see 53" tires much in the old days. So from a relative standpoint, the tires they use are still narrow. You don't see them running around on ag tires like monster trucks use. They have special built tires that are narrow relative to their height.

For the guy asking about sand.. wider is better. But MTs are terrible for sand because that's one terrain where you do not want to dig in and bite.

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post #240 of 1245 Old 09-19-2013, 12:21 PM Thread Starter
Charley3
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Funniest and saddest thing I ever saw at the beach was a new Chevy Suburban with skinny stock tires sunk to the frame rails in sand at low tide. No other 4x4s present had the weight to pull it out soon the tide was coming in. The Suburban owner was on his first ever off road adventure. More sad than funny. It did not end well.

My LJ as at the beach that day with 11.5" wide tires and was easily driving on the sand without spinning or sinking at all. It was to easy.

===

The funniest, saddest, most humiliating and frightening thing I ever saw on a mountain road in Winter was my LJ with 11.5" wide MT slipping, struggling, stuck, sliding sideways off road while a soccer mom in a Ford Explorer with 9.25" (235) wide AT tires easily drove past me with no slipping.

I switched my LJ to 10.5" wide AT and then it did well on that same mountain road in same Winter conditions.

My 96 XJ with 9.25" (235) wide AT was excellent on same mountain Winter road, same conditions.

I haven't yet tried my 99 XJ on that road in Winter, but I'm sure it will be excellent with its 9.5" wide AT.

===

The reason 10" wide tires are my favorites (for an XJ or any similar weight SUV) is just wide enough to be good on sand, and just narrow enough to be good on Winter roads, ideal for mud, and good on highway. I think 10" (255) wide is ideal for all purpose use.

I have 9.5" wide tires because I couldn't find a 10" wide tire in a tread I wanted. So 9.5" is close enough for all purpose use. It's ideal for Winter roads and highway use, and adequate for sand (for my near stock weight XJ).

Warning: I often edit my posts a few times to get them complete, or to correct errors.
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