Today I went to our local Hollister Hills State Vehicular
recreation area. They have a number of trails for 4x4s,
and a special 4x4 obstacles course. There were lots
of vehicles, but I was the only one with "import" vehicle !
All others were Jeeps & GM trucks.

I have 31" A/T tires, 3" lift, Ranchos 9000X, my rear sway
bar is removed.

I went thru about all trails. Everything was fine.
Then I went to the obstacle course, made several obstacles
without problems, then approached the stairs, and there
I had a problem. I could not get up stairs on slickrock.
I tried hard, but no way.

Several vehicles made the obstacle relatively easy. All of
them had open diffs and monstrous mud tires - around 35".
Now I wonder what was the main reason why I did not make it:

1. My tires are A/T tires. Is it so important on slickrock ?
I thought that A/T is better than M/T on rocks.

2. My tires are just 31". Is it the difference between
diameters of 35" and 31" which let larger tires to get over
staircase much easier ?

3. Others vehicles were noticably heavier than my Rodeo.
For example, I saw a pretty silly Suburban, without any
obvious mods except 35" mud tires, which make the stairs
very easy. Is it the weight pressure which makes the
difference ?

4. I have open diffs. Probably, locked diffs would help.
But as far as I could see, others vehicles also had open
diffs and still did it.

5. I have stock 2.05 TC on my Rodeo. May be, this ratio is
too high and I could not control the vehicle properly ?

6. May be, I am just a bad driver ?

To CA, Bay Area guys: was anybody able to make those
stairs in Hollister ?

Oleg
Rodeo 4WD 2002

Well Oleg, I'm probably the least experience wheeler around here, but I can say that the larger tires make a big difference. Mountain bikes with 29" wheels/tires are starting to become the new "thing" (as opposed to the regular old 26" tires). I might not have busted some teeth a few months ago if I'd had 29s. <img src="/forums/images/graemlins/notooth.gif" alt="" />
Of course, locked diffs and a lower crawl ratio would help, too. All those little things contribute in a big way.

I made it up last week with my troop (29'' tires) no problem...did you air down?

1. A/T vs. M/T...A/T's should do just as well as M/T's on rocks and moderatly packed surfaces. The difference between the two is that M/T's 'shed' mud and debris more easily, which keeps the treads blocks clean for a better contact surface.

2. Larger diameter tires roll over obstacles more easily than smaller diameter tires. A smaller diameter tire may have to 'climb'/'pull' itself up and over an obstacle, while the larger diameter tire 'rolls' over the obstacle.

3. Typically low ground bearing pressure is better. Larger diameter and wider tires, which are aired down will greatly enhance your traction, no matter the weight of your vehicle. A lighter vehicle will typically fair better than a heavier vehicle with the same ground contact area.

4. Yes, locked diffs would probably help...just have to convince the wife <img src="/forums/images/graemlins/shiner.gif" alt="" />

5. Perhaps, but a slush box can also yeild more control during a climb to a driver...presuming that you don't have a super low crawl ratio...then it's a push.

6. Live and learn and keep trying. <img src="/forums/images/graemlins/kewl.gif" alt="" />

The thing im wondering is did he bog down the engine going up, as it is a steep climb, or did he just slip everywhere. Next time I go over there again in about 3 weeks, ill have some pics of it.

Chris, I did not air down. I had no air pump with me to
air it back. My tires have 35 psi. May be, this makes big
difference.

Oleg

There is an airing station that you can air up for free about 1 mile down the road where you pay for your entrance...if you did pay LOL! Its over by the dirtbikes at the ranger station. Air down and you'll climb, I didnt airdown the first time and all I did was spin.

I just simply slipped. I had lots of engine power,
no problems in this department, but regardless when and
how I applied the power, I just had no traction.
It was very hot day, the surfice was very dry, covered with
sand - very slippery. I have 265/70-16 tires which is 31".

Thanks, Chris ! I'll do it next time when I'll be there.

Oleg

Simply put, wheel base!

I have only made it up that dam hill once and that was with a bit of momentum, which is almost impossable now with the huge dug out area at the start. 32" MT's at 18psi and a lot of wheel spin is just about all I can get. That hill has the stairs set about 100-115inches apart which is a killer for a rodeo. Even my friends toy pick-up in low-low with 230:1 and 35" had to give up and put it in 4 high and use momentum. The sand doesn't help either.

Your not the only one, I have done tons of trails with no problems, but forget the stairs it just makes me look like a suck <img src="/forums/images/graemlins/butwiggle.gif" alt="" /> driver.

Scott F.