Gentlemen,
I apologize for not responding sooner, but we’ve been very busy lately.
I’ll try to answer all your questions with this post.
Q: Will T. Rex offer a system for the 4x2?
A: We’ve been working on it, but we’re not sure if it’s possible due to the design limitations of the vehicle. We know 4x2 owners need excellent suspension too; it’s just hard to fit everything where it needs to go and still have it work properly.
Q: How does T. Rex suspension perform on the road?
A: Worlds better than OE or any aftermarket system. The difference between OE performance and aftermarket performance is roughly 10 – 15%. And sometimes running an aftermarket shock can be a step backwards in performance because aftermarket shocks were not designed specifically for your Dodge but for many vehicles.
Because, for the most part, suspension is more art than science and therefore subjective, I can’t use concrete empirical data to convey just how good T. Rex suspension is. For example, with engine performance, one can say, “I can boost your horsepower from 300 to 500. ” That can be measured on a dynamometer. You can also measure and compare shock performance on a suspension dynamometer, but the results are meaningless unless you’re familiar with all the concepts upon which that information is based.
Since max-performance street handling of a truck of this size is largely limited by weight, CG, and tire squirm – not to mention speed laws - it’s really hard to generate a hard numbers to convey the amount of improvement we offer. But I’m confidently able to say that the seat of my pants tells me that T. Rex suspension improves high speed stability, cornering flatness, bump isolation, and steering feedback on pavement by roughly 150% over any other suspension product ever offered for this vehicle.
Off-road performance is improved by at least 300% - sometimes more. This statement can be better quantified because of the multiplication of speed our suspension allows. Over most nasty, continuous washboard roads a T. Rex equipped truck can travel at least three times faster than a truck equipped with any OE or any aftermarket suspension product currently offered. In fact, if you were to drive off-road the way many of our clients drive off-road you would break your stock truck in half. I’m not sure what percentage of performance improvement one could attribute to preventing complete destruction of a frame or axle, but I’m sure it would be large. Anyone who has ridden in a T. Rex equipped truck will corroborate these statements.
Q: What about freeway expansion joints? My truck is beating me up on the freeway and my wife won’t speak to me any more until I get it fixed.
A: This is a huge issue. We’ve spent many hours studying this phenomenon. Filming, testing, retesting. We’ve changed everything on trucks just to get them to ride smoothly over expansion joints. It comes down to this: Engineers have to design a pickup truck to handle safely when it’s full of cargo. They devote very little time to designing a comfortable ride when it’s empty; they think about safety when it’s full. They know that the consumer is not going to weigh the load of pea gravel or concrete he’s filling his bed with then shovel some out to match the GVWR of his truck. Whatever cargo capacity your truck is rated for, the factory designs it to handle much more. Your rear springs are hopelessly overbuilt, and to compensate, since you ride closer to the front of the truck, the factory makes your front springs hopelessly soft – so the small, non-repetitive road impacts seem plusher. Because the factory is working within the limitations of low-budget, low-technology OE shocks which have very concrete limitations concerning the dampening characteristics they provide, the heat-related consistency of their performance, and their longevity, the truck’s springs are designed to do most of the work. All this translates into a terrible, unbalanced ride when the truck is empty – and sometimes a terrible ride when the truck is full. Most of our time is spent in an empty truck, so what do we do?
The following is extracted (with explanations added for this post) from the expansion joint study we did two years ago:
This data was generated by filming an unloaded 1999 Dodge Ram 2500 CTD 4x4 LWB with stock suspension while it crossed expansion joints on the 405 freeway near Long Beach, California at a speed we determined to be outside its “sweet-spot. ” The sweet spot is the best speed (by feel) for functioning of the suspension. The speed we used was the worst speed (by feel) - 67mph. We played the tapes back in slow motion and watched the axle movements relative to the chassis and the pavement. Then we made changes to the suspension based on our assumptions. The changes we made allowed us to scientifically determine what was really going on under the truck.
Event 1 – Front axle hits joint 1, rushes through travel [spring too soft] shock blows off [OE shock provides insignificant high-speed compression dampening]
Event 2 – Rear axle hits joint 1, deflects chassis upwards [spring too stiff], chassis unloads partial weight on rear wheels
Event 3 – Front axle hits joint 2, still riding low in stroke [OE shock is holding front axle up because of too much high-speed rebound dampening] – even less available travel to absorb impact
Event 4 – Rear axle hits joint 2, now downwards momentum of bed forces minor leaf compression. Leaf pack responds, unloading chassis to a higher degree than manifest by Event 1 [spring rate overcomes shock’s rebound dampening]
Event 5 – Front axle hits joint 3, axle touches bump stop, effectively bottoming [no available travel left due to excessive rebound dampening – also known as “packing”], bump stop compression vaults axle away [not enough rebound dampening to keep axle from springing back in a controlled manner]
Event 6 – Rear axle hits joint 3, more downward momentum results in more perceived impact
Event 7 – Front axle hits joint 4, chassis still in upward momentum – lower perceived impact
Event 8 – Rear axle hits joint 4 - replicates Event 6
Event 9 – Front axle hits joint 5 - now has downward momentum [light spring, low compression dampening] axle bottoms harder on bump stop, rebounds faster
Event 10 – Rear axle hits joint 5 – replicates Event 6 but perceived impact is reduced due to weight now biased towards front, since front is deeply loaded
Event 11 – Front axle hits joint 6 – less perceived impact due to lower effective weight on axle – more travel to absorb impact
Event 12 – Rear axle hits joint 6 – weight now biased towards rear, perceived impact greater
As you can see there is an uneven harmonic that develops between both axles. Each axle creates a different pattern due to their respective problems. The front wave has three essential points and the rear has two. Ever wonder why sometimes you don’t feel every expansion joint you see as you drive over them? That’s why. It’s not because some are bigger and some are smaller. It’s the imbalance that causes this mysterious phenomenon. This imbalance is ultimately sent through the truck’s frame and into your wife’s spine. If you change speed or the distance between the joints changes, it upsets the pattern and a new series of problems occurs. If your OE or aftermarket shocks are worn out a new series of problems occurs. If your front springs are sacked out a new series of problems occurs. If you’re running air bags a new series of problems occurs. If you’re towing a new series of problems occurs. If you’re driving a SWB truck, you change the effective distance between the joints and a new series of problems occurs. The event analysis shown above may not even apply to your truck, but each symptom does. I could write at length on each of these issues, but that’s beyond the scope of this study.
I will say that the addition of T. Rex suspension components will make your big, heavy truck more balanced and ride properly over expansion joints - in a way that the factory engineers never imagined possible. I don’t care what year your Ram is, or if you’re running the OE overload springs and/or some Firestone airbags – or if you’re towing a thirty foot fifth wheel trailer. The key is in our front spring and our shock’s progressive dampening that is working together in a way that factory or aftermarket suspension just can’t. Due to your heavy rear leaf pack that must be retained in order to carry a load, you will still feel expansion joints sometimes, but the sensation will be greatly reduced and the imbalanced harmonic totally eliminated
Q: What about the OE sway bars?
A: They work fine, so we keep them. Our philosophy is to retain as much of the stock design as possible, but just improve and modernize the components.
Q: What about the stock overload springs? Are they causing my OE suspension to be harsh?
A: No matter what kind of overload system your Ram is equipped with - over the main pack or under - the overload leaf only comes into effect towards the end of the suspension travel. We suggest you leave them on for towing or heavy loading. They’re not even affecting your ride when the truck is empty because you’re only getting into the first third of the stroke.
I'll get to the rest of the questions in the next post - I think I've exceeded my limit in this one! Yikes - I'm long-winded!
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