The side of the tire Max Pressure is simply that, "Max Pressure" or the designed maximum
that the tire was engineered for.

The correct tire pressure is dependent on the size of the tire and the load it has to carry, I
run a 33 13.5 Swamper, the load capacity of 1 tire is greater than the weight of my whole
truck, and running it at the maximum pressure would be like having rocks for tires.

I ran the Swampers as a daily driver at a pressure of 12 PSI and got about 25K miles from
them, not bad as these are not known for being a high mileage tire.

When I go wheeling I run them at 3 PSI and there is really not much difference in ride
height than at 12, that is until I crawl over rocks, then they wrap around the rocks and
really dig in

Wild

Typical! I guess to post a reply on this forum you really need to be a professional professional. Based on what I read in the original post, I gave a suggestion from my experience on my vehicles and BAM! just like every other post on this forum someone chimes in has to make THE correction so that this chap and his bride can move along down the HIGHWAY with nothing to fear.

Typical! I guess to post a reply on this forum you really need to be a professional professional. Based on what I read in the original post, I gave a suggestion from my experience on my vehicles and BAM! just like every other post on this forum someone chimes in has to make THE correction so that this chap and his bride can move along down the HIGHWAY with nothing to fear.

If your suggestion is so far out of whack that it's likely to lead folks astray, then expect to get called on it - and yes, I understand it's your experience, but, I have to assume it's not experience with a Suzuki - none of the Suzuki 4WDs I've ever seen run the factory size tires anywhere close to max pressure.  As an example the max pressure on my tire (Dunlop Grandtrek AT3) sidewall is 51 psi - I run them at 26 psi, just about half the maximum rating, which is what Suzuki recommends for that size tire.

What was it you said - too much below - 25 psi sounds like too much below to me, those tires have been there a year, rotated them just last weekend, the tread wear looks nice & even to me.

Like Wild says - the max pressure is the design maximum - the "DO NOT EXCEED" and bears absolutely no realtionship to the preesure to be used - one is set by the tire manufacturer and the other by the vehicle manufacturer.

Well let's see, I was the first to reply to this post, and by the looks of it I pegged
the problem and then offered a solution, albeit a lower one than was suggested,
(15 PSI Vs 20-25 PSI) and I take no offense to that suggestion, I run a big heavy
wall tire, and it stands up to lower pressures better than many tires others run.

I actually don't see any suggestions you offered to solve the problem, only a "much
lower pressure" advice that many here have learned is still much too high of pressure
for these very light trucks, as I stated the OEM tires at 205/75-15 were called out
on the tire placard on the truck to have 23 PSI(sidewall called for 36) roughly 30%
lower than the sidewall called max, a much larger tire like the ones the question was
asked about surely could go lower than that.

This is why I also suggested using the chalking method, it most accurately shows
how the tires are going to wear before you do cause wear problems, but if you feel
that on your vehicles staying close to the sidewall max pressure is best, that is your
choice and I'll let you make it.

I was only giving advise from my personal experience of logging over 250,000 miles in
a lifted Sidekick with oversize tires, I started with 235/75-15, and went to 31-10.5-15
and then I jumped to 33-13.5-15 Swamper LTB's and I love them, loud noisy and 
kick lots of sand and dirt when I play.

Ohh, and the chiming in and making a correction, that's actually what you did correcting my post

Sorry you took offense to my explanation of what the Max pressure is there for

Wild 

My 2 Bits,

I am running Good Year ATX Wrangkers 31x10.50x15's on stock rims on a 87 sammy.
Fronts at 22 psi, rears at 26 psi (I carry a lot of Trail Gear along).
Cruise on highway no promblems other than what a very short wheel base give you for ride.
KD to 12-16 psi on trails (Not much lower, I don't have "Bead Locker's)
and get around great.

CAPT

I'm assuming bead lockers allow you to go with less pressure??

This i know --  My tires are rated for max 55 or 58lbs....  I had 38lbs and the bumps were servere enough that I would have sold my samurai if I would have been told "that's just how it is"...   based on recommendations I'm running 22.5lbs and the difference is night and day and I can now see why there is a love and following for the beloved Samurai. 

This weekend I'm performing the chalk test and we'll see if i can go to 15lbs like what Wild does.

So my wife and I were riding in our new to us 90 Samurai SJ SPOA and we couldn't help but notice the bone jarring bumps...  Is there something I should replace/upgrade on the Samurai to ease the bumps --

If you have not discovered it yet, you probably will, all of the modifications we make to our Zuke's will have compromises. I think this is especially true in tires and how our SPOA is setup. As you have discovered, the tire air pressures are the easy to change when looking for a softer ride.  I run 31x10.5x15 tires, with about 25 psi as a DD, and on trails, I might run 12 psi. My wheels are 8-inches wide. I have lost a bead two times running 8-psi.

My Zuke only has about 2-1/2 to 3-inches up travel in the front, and 2-inches in the rear. With this short up travel, I do get more bone jarring bumps than I would with increased up travel. It is a compromise. I have the Trail Tough YJ SPOA kit on my Zuke. You may find this of interest, it will explain my short up travel.

Shock and Shock Mount Placement   http://www.trailtough.com/index.php?option=com_content&view=article&id=56:shock&catid=36:techinfo&Itemid=60

I run the Doetsch DT9000 shocks with built-in bump stops. They were included in my TT SPOA kit.

http://www.doetsch-shocks.com/2.asp

I was to told to buy new shocks that are 2" longer than the ones on there now?  I can only imagine how it's going to be off-road.

I don't know how much you want to know about shocks, but this link will give you much valuable information, including how to measure for the length of shocks, and how and why they should be mounted. It is my understanding, if mounted incorrectly on the axle, you might have issues with axle wrap.

Be A Genious - Shock Absorbers  http://www.4x4review.com/Features/Tech/BeAGeniusShockAbsorbers/tabid/307/Default.aspx

What do SPOA people do to cushion the blows?

I don't have anything fancy...  the only modification it has is a SPOA.  

As has been posted, lower air pressure is the least time consuming, and expensive. From what I understand, longer springs with fewer leafs also cushion the blow, as does the type of shock. YJ springs are very popular, have a relatively good ride with good flex. They all have compromises.


Wayne

I have never ridden in anyone else's Samurai other than mine but I haven't stop making changes to it since it came home. I have however ridden in a bazillion off road vehicles thoughout my time.

I run 34 x 9.5 TSL Swampers and will attest to the lower pressure / better ride comments. It also might have something to do with the ply of the tire. A 6 ply sidewall isn't going to flex and be as forgiving as a 4ply.

As far as shocks are concerned length is only a significant factor depending on the amount of flex desired. You can buy different shocks with varied dampening abilites and reservoirs as well as ride selection abilities. The latter will allow you to make some subtle changes to the ride quality.

Currently I have a RUFF set up but plan on going SPOA so I watch and read with interest any commentary post on several forums concerning SPOA set ups.

Another thought I have is with your springs in relationship to what they are and how many leaves you have. Stock springs shouldn't give you many fits but if additional leaves were added for more lift or if add a leaves or overloads were installed these could be part of the problem. If they would happen to be aftermarket springs again these could be effecting the ride as well.

NOW..... Let the bashing begin....   J/K actually I think the folks on here have some pretty sound advice and experience to back it up. I know that I appreciate Wild - Fordem - Drone & JLuck for their posts.... they have helped me out with their words of wisdom about Zuks in their posts!!!    

remember me telling you that you have to break the swampers in correctly? you never asked me how? (for tuxblacray)

Yep.... sure did!!!

LOL... they aren't new so I figured the were broke in....   at any rate they are fine. I had them balenced and I thought for sure I would need to peel the weight off and and replace it with ball bearings.  I am going to install  high steer mercedes arms next. (Although I have no bump steer issues.) I am doing this as a precautionary measure pre-SPOA.)

I am considering going with add a leaves to give me the necessary clearance vs. SPOA. I am only struggling with if this will be enuff clearance to provide enuff bounce distance... Something tells me yes but my mind says naw go for the SPOA to be sure!  

Right now if I bounce the front end it will reach up and grab the rear of the front fenders. I believe that add a leaves will give me about 2" and would eliminate this issue while leaving me SPUA.

I'm not all that concerned about clearance issues given the frequency and places I would be wheeling. a couple of other positive reasons would be it keeps my center of gravity lower reducing the tip factor and I wouldn't have any driveline issues or have a need to modify my shock mounts any further. Likewise I am not sure I wanna be 3" - 4" higher and build some special rock rails to enable me to get in.

ya spoa is great on a Sammie, you get rid of the u-bolts hanging down and catching everything, and it gives you way more flex.

What do you use in place of the u bolts ?

What do you use in place of the u bolts ?

He didn't say you get rid of the U-bolts....... The U-bolts face up instead of down. Therfore the spring plate and the nuts are on the top. That is what he meant by them as not catching up on everything.....

Ahh...thanks!

So thankful i found this thread. My sammy was a tooth jarring ride. I took out the pressure gauge today. I run 235/70.15. The front tires had 38PSI and the back was 32!!!!

Using the chalk method, 24 seems to be the magic number for my tires. The ride quality is HUGE difference. I wouldn't want to try surgery in it while going down the road but it is definitely better.

Thanks to all who contributed to the thread your help is always appreciated.