4x4 / Off-Road TechThis section contains all discussion related to taking the FJ Cruiser in Off-Road situations, 4x4 applications and any armor modifications.
Back on thread, I used to have a '47 CJ-2A, and yes, for the vehicles that were around at the time, it would pretty much go anywhere. (Time I had it, 79-81)
If I'm not mistaken, part of the design criteria as far as the weight was that 4 soldiers were supposed to be able to lift/push it out of most stuck situations.
I don't think they had computer designed lug patterns for noise reduction either...
LOL, dick cepeks were hand cut? Gates rubber made muds back in the 70's. Back then many retreads were the way to go.
Read the link Lance posted. Also, tire companies make tires that people will buy, just like car companies make crappy cars that people think are cool. Don't tell me how many posts you've read here where people talk about the tires looking "cool" or "buff", etc. You think Nitto's look that way because their side wall performs better than a Goodyear or BFG?
And some of you people rag on savage for "reading and doing research".
Just looked it up, DC started by having Armstrong tires make wide tires for him, In 1963, fior his land cruiser. Friends wanted the wider tires so he bought enough to fill his garage and started to sell them, and he experimented with tread design hand cutting them.
OK... So what if you have an object in front of the brick? Changes things don't it? The larger surface area piles up snow that causes the tire to have to overcome gravity and this self made barrier, the larger surface area=less down force to cut thru. I've seen this and experienced this several times. Fat tires in snow=BAD Pizza cutter in snow =GOOD.
I fully disagree.
If you're in deep snow and you sink in low enough, you can drag your undercarriage and get stuck (I've pulled LOTS of people out because of this). If you have wide tires, you can float. Thats why they call them "floatation" tires!
If you're silly enough to go out in the snow with road tires or AT tires that don't have wide open voids, then nothing can help you and this is because of the SURFACE CHARACTERISTICS that we talked about in my last post. Just like under an ice skater's blade, the melted snow on the surface is an EXCELLENT lubricant and effectively zeroes "stiction".
Do snowmobiles lack for grip due to a wide traction surface? Does a snow cat have any problems?
There's nothing fantastic about "pizza cutter" widths that you don't get with a wide tire.
In the end, at the same tire pressures with the same weight vehicle, a thin tired vehicle and a wide tired will have basically the same surface area contact anyway. This is because the pressure in PSI is being exerted on the ground by the pounds, "P," of the vehicle. If the vehicles are the same weight and the tire pressures are the same, then so will the "SI", or square inches!
You can actually "weigh" a car by measuring the area of tire contacts and then multiplying each one by the measured pressure in the tires before adding them all up.
Not only is static friction independent of surface area, but you don't CHANGE surface area contact appreciably by your tire choice, wide or skinny.
Here is an extremely well written paper on tire choice, not something you see in off-road rags that bolt on the latest Big Bling and place the vendor's advertisement on the same page.
OK... So what if you have an object in front of the brick? Changes things don't it? The larger surface area piles up snow that causes the tire to have to overcome gravity and this self made barrier, the larger surface area=less down force to cut thru. I've seen this and experienced this several times. Fat tires in snow=BAD Pizza cutter in snow =GOOD.
Depends on the snow. If you are in 6 inches to a foot of snow, sinking down and finding the ground is a good thing.
Anything more than a foot of snow, you want to stay on top of. Where a wide tire is good. Where we wheel, the bigger, wider tires whoop ass. Aired down to 1 to 5 psi, you get that huge contact path. Like show shoes, it keeps you on top and onward to victory.
Where we wheel, in the deep stuff, the wider the lower psi, the better.
__________________
___________
Timber Tamers 4x4 Club
"Turning our hubs in, Where others turn back."
Quote:
FJ Tex previously said:
oh and i think i may be wrong about the physics, i think Stephen Hawking may have TSL Thornbirds on his chair.
LOL, dick cepeks were hand cut? Gates rubber made muds back in the 70's. Back then many retreads were the way to go. ... Also, tire companies make tires that people will buy, just like car companies make crappy cars that people think are cool. Don't tell me how many posts you've read here where people talk about the tires looking "cool" or "buff", etc. You think Nitto's look that way because their side wall performs better than a Goodyear or BFG?
Quote:
highbeams previously said:
you have to remeber that was top of tire technology in 1941, In fact the off road tire was not truly invented until the 1980s when Atlas Tire Co came out with the first tire to use a z pattern in it's tread, before that most off road tires were hand cut. Since the introduction of the Atlas tire the bridge has been expanded to what is offered today. 2 decades is not a long time considering the length of time tires have been made.
Quote:
highbeams previously said:
you know Dick Cepek started out by selling hand cut tires out of his garage, well documented it is, Before Allied most offroad tires where either huge lugged, in strait patterns, or had tread running strait down the center such as a average 50 dollar tire today. If you look at any modern AT tire, and Most modern MT tire today, the lugs are cut in a Z, or Z hybrid pattern. It has been found to grip better offroad offering the most amount of surface area for the length of tread gripping.
another point you may be missing is what is called a side biter, the lugs on the sides of tires are there, to help grip rocks surfaces, Yes many guys use their sidewalls a lot off road, in fact that is why guys like brands of tires with extra sidewall ply. You simply have to look at the tires a guy who wheels around rocks a lot to see that they are hammered on the sidewalls also. Yes sidebiters have a reason to be there. I personally do not run Nittos, prefering Mickey Thompsons or Dick Cepeks myself, but if that is what grabs for you, go for it.
Quote:
highbeams previously said:
Just looked it up, DC started by having Armstrong tires make wide tires for him, In 1963, fior his land cruiser. Friends wanted the wider tires so he bought enough to fill his garage and started to sell them, and he experimented with tread design hand cutting them.
Okay, I'm not going to get into a "SeanK" with you... :-) Just try to clarify what I was saying. Yes, back "in the day" (I'm guessing you're not a 20 something - either am I), the only way to try a new tread design was to hand cut it. Freddie Spencer had to hand cut his tread when he first started motorcycle GP because the Americans were used to races being called for rain, not in GP, so after the pit crew stood around staring at each other, Freddie cut his own tread pattern. My point was I don't think DC sat in his garage cutting tires for 17 years. As I posted, Gates Rubber made many different "brands" of offroad tires for other companies in the '70s, don't know about the '60s, and DC-FC's were very popular in the '70s.
As far as the Side Biters, um, yes I understand. I personally run load range E BFG's, and you're more than welcome to look at the scoofs/scrapes/gashes in my sidewalls anytime (I could have just said "DUH" here, but that would have been rude). My point was look at the biters on a BFG, whether AT/MT or Krawler, very basic, and it works. Look at the "biters" on a Nitto Mud Grappler, they look "cool". Just by looking at them it appears that an argument could be made that they are actually angled improperly for maximal functionality, but, hey, they look COOL. Does the cool texturing on the sides between the biters do anything? Look at the homepage for BFG and for Nitto, marketing to two different crowds I might think.
Hope that makes sense.
Oh, not familiar with the Atlas z pattern stuff you mentioned, if you have the time could you please PM me some info/links on it? - thanks!
Depends on the snow. If you are in 6 inches to a foot of snow, sinking down and finding the ground is a good thing.
Anything more than a foot of snow, you want to stay on top of. Where a wide tire is good. Where we wheel, the bigger, wider tires whoop ass. Aired down to 1 to 5 psi, you get that huge contact path. Like show shoes, it keeps you on top and onward to victory.
Where we wheel, in the deep stuff, the wider the lower psi, the better.
X2
Very well put, couldn't agree with you more.
That first picture also shows no matter how wide, you may not be able to stay on top and moving... winch cable out...
Here is an extremely well written paper on tire choice, not something you see in off-road rags that bolt on the latest Big Bling and place the vendor's advertisement on the same page.
What is important is not their final choice but the actual thought process used to reach that choice.
As I stated above, the document is flawed. They assume same PSI air down levels. I counter that if you air down two similar height tires to the same side wall height, the contact patch will be better on the larger tire. They also failed to discuss rotational friction.
It's not a scientific paper nor site. It's an outdoor automotive site, written by someone who may or may not be a physics major. I guess on the "not" side. A search of "wikipedia" or "howthingswork" will give a different explanation. And yet, their own calculations suggest what we already know -- a 9.0 to 11.5 width tire is ideal for our rigs.
__________________
Ross Woody
Vallejo, Ca
TLCA Secretary TLCA #7704 Rubithon Kitchen Committee
72 FJ40 * "Mudrak Improved"®
07 TRD FJC
As I stated above, the document is flawed. They assume same PSI air down levels. I counter that if you air down two similar height tires to the same side wall height, the contact patch will be better on the larger tire. They also failed to discuss rotational friction.
It's not a scientific paper nor site. It's an outdoor automotive site, written by someone who may or may not be a physics major. I guess on the "not" side. A search of "wikipedia" or "howthingswork" will give a different explanation. And yet, their own calculations suggest what we already know -- a 9.0 to 11.5 width tire is ideal for our rigs.
Good points, yet, with all due respect, I don't know of a "scientific paper/study" which has been published on such a topic. If you know of one, please share. I can see the validity of doing such a project yet doubt anyone would invest the time or money to do something more than a "Mythbusters" type experiment...
And, as to width size, there are many who are running 12.5" tires and larger in width where my "pizza cutters" are in the middle at 10.5, which, in my mind is the perfect width tire for the FJ Cruiser. Yet, to argue against myself...when I was in Moab this summer, going through "Wedgy", I saw the advantage of the wider tires there. All the guys with wider tires than mine had a bit more margin of error than I did. Nothing that couldn't be dealt with but it was clear that a couple inches here and there can be helpful...
As I stated above, the document is flawed. They assume same PSI air down levels. I counter that if you air down two similar height tires to the same side wall height, the contact patch will be better on the larger tire. They also failed to discuss rotational friction.
It's not a scientific paper nor site. It's an outdoor automotive site, written by someone who may or may not be a physics major. I guess on the "not" side. A search of "wikipedia" or "howthingswork" will give a different explanation. And yet, their own calculations suggest what we already know -- a 9.0 to 11.5 width tire is ideal for our rigs.
Never said that the site or paper were "scientific". I said that they had a thought process as opposed to the usual emotional responses to someone dissing someone's elses favorite dogma.
Show me a better written white paper and I'll read it. Include airing down procedeures for different tires, rotational friction and rubber compounds. Sounds GREAT!
Attack the referenced paper all you like but they are only attacks without a framework or thought process to reference them to. If you've written a better paper please share it so that we can discuss your scientific approach to the issue.
I'm not being snippy. Please share your knowledge.
Quote:
Teotwaki previously said:
Here is an extremely well written paper on tire choice, not something you see in off-road rags that bolt on the latest Big Bling and place the vendor's advertisement on the same page.
Pizza cutter in snow =GOOD.
Linear Mode
