With the release of the new Rancho 5000x shocks, we are seeing a lot of people recommending that shock for every setup. I put forth my opinion in another thread that you will have a better setup if you match the Rancho shocks to the Rancho springs or at least a spring that has a similar spring rate. It is my opinion that spring rates and shock valving work hand in hand and you will have your best results running a spring and shock combo that are designed to work together. Pairing the Rancho shocks with a spring that is much more firm than the shock was designed around will result in poor control of the suspension travel.
I have arrived at this conclusion through my own experience. About 10 years ago when I put my system together the new adjustable Rancho 9000XL was all the rage and everyone on jeepforum recommended it. Wanting the best I could afford, I paired the Rancho shocks with BDS springs. The setup in front was fine, but the rear end would dance across pot holes and the body would spring up uncontrolled after dips in the road. It seemed the shock simply could not control the suspension in the rear. Most notable was the lack of rebound dampening. Compression felt fine.
After 2 or 3 years of aggravation, I finally decided to drop the coin for some Bilstein 5160s. I decided nothing would change ride quality more than shocks and they should last 50,000 miles. So I would just spend the money and get what I determined would fit my needs the best. Sure enough, it worked. The Bilsteins handled the rear end perfectly. This was the proper solution in this scenario. (Your situation could be different)
To provide additional information: Nothing else changed. Only the shocks. I simply swapped out the Rancho 9000Xls for the Bilstein 5160s with no other changes. I think the shocks had about 25,000 miles on them. So they were not new shocks, but still had plenty of life left in them. In fact, they are in good enough condition that I just put the front Rancho shocks back on because I over extended my Bilstein and needed a quick replacement. But the spring rates in the front don't vary as much as the rear springs. So the front was never an issue. It was always the rear shocks that couldn't control the downward movement of the unsprung weight or the upward movement of the sprung weight. This makes sense when you consider the shock was designed for a spring with a rate of 150lbs and it was trying to control a spring rate of 200lbs. That is a a 35% increase in spring rate.
I suppose travel bias changed slightly. Compressed length of the shocks are nearly identical, however because the Bilstein are remote reservoir they extend an inch further in the rear and 1 1/2" further in front. So the Rancho probably had a better 50/50 up/down bias. But I don't think the extra length when extended would matter. Particularily when driving on the road. Which is where the Ranchos had the most trouble. Slow travel offroad I did not notice the issue so much. So I attribute the improvement solely to pairing the spring to a shock that was designed to handle a stiffer spring.
So that is my experience. What is the experience of others who have changed out nothing but shocks. Can a good shock work with any spring or do shocks and springs need to be paired to work together? I know what I have found out. Whats your experience.
I have arrived at this conclusion through my own experience. About 10 years ago when I put my system together the new adjustable Rancho 9000XL was all the rage and everyone on jeepforum recommended it. Wanting the best I could afford, I paired the Rancho shocks with BDS springs. The setup in front was fine, but the rear end would dance across pot holes and the body would spring up uncontrolled after dips in the road. It seemed the shock simply could not control the suspension in the rear. Most notable was the lack of rebound dampening. Compression felt fine.
After 2 or 3 years of aggravation, I finally decided to drop the coin for some Bilstein 5160s. I decided nothing would change ride quality more than shocks and they should last 50,000 miles. So I would just spend the money and get what I determined would fit my needs the best. Sure enough, it worked. The Bilsteins handled the rear end perfectly. This was the proper solution in this scenario. (Your situation could be different)
To provide additional information: Nothing else changed. Only the shocks. I simply swapped out the Rancho 9000Xls for the Bilstein 5160s with no other changes. I think the shocks had about 25,000 miles on them. So they were not new shocks, but still had plenty of life left in them. In fact, they are in good enough condition that I just put the front Rancho shocks back on because I over extended my Bilstein and needed a quick replacement. But the spring rates in the front don't vary as much as the rear springs. So the front was never an issue. It was always the rear shocks that couldn't control the downward movement of the unsprung weight or the upward movement of the sprung weight. This makes sense when you consider the shock was designed for a spring with a rate of 150lbs and it was trying to control a spring rate of 200lbs. That is a a 35% increase in spring rate.
I suppose travel bias changed slightly. Compressed length of the shocks are nearly identical, however because the Bilstein are remote reservoir they extend an inch further in the rear and 1 1/2" further in front. So the Rancho probably had a better 50/50 up/down bias. But I don't think the extra length when extended would matter. Particularily when driving on the road. Which is where the Ranchos had the most trouble. Slow travel offroad I did not notice the issue so much. So I attribute the improvement solely to pairing the spring to a shock that was designed to handle a stiffer spring.
So that is my experience. What is the experience of others who have changed out nothing but shocks. Can a good shock work with any spring or do shocks and springs need to be paired to work together? I know what I have found out. Whats your experience.
