I have a 04 2wd SE replaced the fronts with KYB gas adjust and i tow alot so my mechanic put a set of Monroe® Sensa-Trac® load adjusting shock absorbers to help with leveling out my ride when towing but the ride is harsh and on the highway it shakes and is very fatiguing on long rides.I think the rears are too stiff?New tires were also installed and aligned tires are great just the ride went to the shitter.If i put Billsteins on the back will this smooth out the ride or replace the fronts also?
I don't go offroad just city and highway driving looking for the smoothest plushest ride with control?

You say you got new tires too? What did they set the PSI to?

I have Kumos K51 great tire max pressure on tires is 51 cold.
I've tried all from 45 47 40 42 and 35 32 the truck settles at 35 but the tires feel heavy and doesn't ride well 42 and 45 is where it feels right on the road but the truck is just to stiff?

I should add that in the city it's not bad but over 55 it starts to get harsh i feel every little bump and at highway speed 65 70 it's resonates into me.It's not a tire pressure thing it's a to stiff thing.
This is what's in the rear.

http://www.monroe.com/products/sensatrac_loadadjustshocks.asp

Anyone!

i am not to sure but maybe those shocks are to stiff for you for daily driving. since he put them on to help level out when you tow, it sounds like they are to stiff when you are not towing.

You are correct sir!
Yes they did fix the level problem with towing but that's it!They feel like a jackhammer otherwize.I'm sure it's effecting the front to the trucks sits about 1.5 to 2 inches higher in the back!
Does anyone know how much better the Billsteins are compared to the KYB's or Stock?

i have the ranchos and i love them, i have heard great things about rancho and billsteins and they are both worth the money, but most people really love billsteins.

i have had monroe and stock and they both sucked so bad compared to ranchos, a lot smoother and better handling. i can't speak for billsteins but i have heard the same reports.

I have Bilsteins in the front and the adjustable Ranchos in the rear (the RS9000 5 way adjustable, not the newer 9 way adjustable).

When I go off-road or tow, I set the rears to 5, which is the stiffest. When I drive normally, I set them to 3. Unfortunately, the knobs got turned the wrong way once and now seem to be stuck on 5 which does ride harsh when I am not towing or not off-road.

The Ranchos are expensive, a good bit more expensive than the Bilsteins. Both are great shocks. I think when towing, the Ranchos set on the stiffest setting will be better than the Bilsteins.

-Michael

Thanks

I'd say cross-check the part numbers with Monroe and make sure they're the right shocks for your X, then take a look at your tire pressures. They sound high. Use the placard pressure (it's 26 lbs for my '01 V6 4x4) as a starting point, then maybe do the chalk test or contact Kumho for a recommendation.

Well, what's the rebound/compression valving on the shocks that might be too stiff?

They have a coil that ADDS preload...so, the shock is going to require valving to:

1) Control the weight/motion of the axles, tires, etc (Unsprung weight)

2) Control the weight/motion of the frame on up (The sprung weight)

3) Control the compression and extension of that COIL. (Spring rate)


It could also be that the valving is not responsive to the road, so that even if the #'s work, the shocks have too narrow a response curve to be able to be comfortable for both towing and unloaded conditions.

The Bilsteins use a state of the art monotube shock with digressive valving, and they ride really nice, whether loaded or empty.

Another issue that the tires may simply be a poor match for your truck.

This can happen too.

You say 51 psi is the max psi...that's an odd number....are you SURE?

How many lb does that support at that max psi?

Here are the spec on the tires.

http://www.tirerack.com/tires/tires.jsp?...1&tab=Specs

As far as the rear shocks they were not made for the truck but have the same sizing as other replacements so they fit without any modifications just bolted on.But they may be just to stiff and not the right suspension curve for the X but they keep it level when towing which is only a 18 foot flats boat!

Tire pressure is 35 front & rear on the door panel but I think running them that low they feel the best no vibrations but the truck feels slugish and i don't think they will wear right!

My take is to replace the rears with Bilsteins and see what happens leave the front KYB gas adjust on the fronts and see what happens then replace the fronts with Bilsteins if it's not riding right then!

what year is your xterra??? my door pannel says to keep the tire pressure at 32 psi, i run at 35psi though.

2004 SE 4x2 3.3

Anything above 32 - 35 psi and you are just looking for a harsh ride.

I actually had some bone head at the tire shop put 50psi because "thats what is said on the sidewall"

No matter what the tire max is?
i'm running 42 f 45 r

No, it matters what the max for the tire is...there is NO universal PSI that is perfect, no matter what rig or tire.



For the tires actually under consideration:

It DOES say 51 psi Max pressure, and, that the max LOAD is 2,469 lb at that psi.

If your X's GVWR is ~ 5,200 lb, you take 35% of that, and say you need each tire to be inflated enough to support 1,820 lb

1820/2469 = ~ 0.74

So, we need the tire to support ~ 74% of its max capacity....so, we need about 74% of its max PSI to get that, or ~ 38 psi.



Not all tires ride well at every psi though, as they are often optimized for a particular range of rig weights....and if YOURS is on the light side of that, or less, YOUR ride might be too harsh...even if the psi is "right".

The same way a really heavy f350, etc, may bitch that the SAME tire, even at HIGHER psi, is too wishy washy, and so forth.

So i spoke to my dealer about the shock we put on the back the Monroe load adjust with the coil over springs.I logged over 3000 miles so far and i told hime i can't take the ride it's to harsh at highway speed so he is going to swap them out for the KYB gas adjust tomorrow like whats on the front and will see if that fixes it!
I did solve my trailering leveling problem but the ride was just to harsh i will report back!

Let us know...

You could try air bags if you tow a fair amount. That would allow you to have shocks that would be good for when you're not towing and then have something to help when you were under load.

As for the tires, that does seem high. Do you get uneven wear ?

yeah, hope he has a better chance of finding bags for an 04 than I did for mine.

So i had the shocks switched out to the KYB's gas adjust they are way better than those monroe coil overs the truck feels stiff like it was when it was new if not better.The truck sits prety level with my boat towed it today 3 hours it only dips 2 inched in the rear and comes up only 1/2 inch in the front.It is stiff i need to put a few more mile on them to break them in and i hope they soften up a little.i don't know how much better the ride would be with the bilsteins front & rer compared to the KYB's but owell.Anyone have a fix for the passenger seat shake on the highway while it's empty?i need to mess withthe tire pressure i ran them 34 f 37 rear one way and reduced them to 32f 35r for the way home.i liked it better before i'm going to put it back up to 42 where my dealer had them when i pulled ou and see how it rides.The tire are wearing well i have 3,300 mile on them and did a rotation on them when they switched the shocks.if anyone has some info for me please offere it.

Phil

Have you thought about getting a weight distribution hitch system? They distribute weight to both axles and keeps the truck more level. The rear of the truck should not dip at all, that can cause the trailer to sway. A weight distribution hitch will keep the rear of the truck from dipping and the front from raising up.

-Michael

That is not needed.My boat only weighs 3500 lbs.