Suspension Question

[SoCalMonty]

Thanks for the replies everyone.

SoCalMonty, if I'm understanding right, did you end up mixing and matching your suspension? Are you running Ironman coil springs and torsion bars along with KYB GAJ's? This was something I was wondering about. I didn't know if it was a good idea to go KYB's for absorbers and buy springs and torsion bars from OME or Ironman. I'd be curious if you guys had opinions on this.

My assumption was that companies like ARB and Ironman tune and design everything to work as a system so that you'd only get the best performance out of each component if it was working together with the other parts from the same company.

Here's another suspension related question. When do you know that you need to / or should replace your torsion bars? When I spoke to someone at Rocky Road Outfitters about the OME kit, he recommended just buying the shocks and coils for $499 instead of the entire kit (w/torsion bars) for $7??. I am wondering if I should initially just change out shocks and possibly coils and hold off on replacing torsion bars. They don't appear to ever have been cranked, but I'll be taking a closer look this weekend.

Trust me...not nearly as much engineering as you think goes into these aftermarket parts. I've worked for a few related companies. Typically, they take the numbers from the stock unit (in this case, spring rate and wire/bar thickness), surmise they want it, for example, 9% stiffer, then contract a manufacturer to produce it (the mfr often knows more about the items than the aftermarket companies do, and will often advise the aftermarket brand as to what's possible and what's not, depending on their working relationship). Then the mfr. kicks out the parts, stamps them with the aftermarket brand's fancy logo, and you've got pretty aftermarket parts. Occasionally, it's all done in-house, but these days 95% of crap is either made from parts sourced in, or completely manufactured in, China.

Mixing and matching is perfectly OK. You just have to do your homework. Contact the companies, ask for the product's specifications. Match accordingly. In my case, as I mentioned, they work just fine together. We aren't talking racing parts here - the OME and Ironman stuff is just "+1" from OEM. Nothing extreme. Quite frequently, there will be several options for a part with marketing that makes them sound vastly different, when in reality, they are nearly identical in performance.

Think of it in other ways. How many people have a Mitsubishi engine and a K&N intake? Or a Jeep frame with Rubicon Express leaf springs? Isn't that mixing and matching too?

As for the T-bars...if you've used up all of your adjusters and your truck is still sagging, it wouldn't be a bad idea to replace them. You could always reindex them to get some lift back with more tension on the bar, but if the torsion bar has softened and sagged, it means it's not going to perform the way it should, and you can probably feel the difference at that point.

A frequently asked question from our torsion bar customers is, "How long should a torsion bar last?". The answer lies in how close to the material's yield point the bar is used. The closer the stress exerted on the bar is to the yield point of the material, the shorter the life of the bar. Consistently take a bar past its yield point and the life starts to go out of the bar. A high quality bar will not lose it's spring rate, it simply will not be as responsive as it is designed to be. An analogy would be to compare torsion bars to valve springs that test OK but the engine will not perform at its peak.

 

[off-roader]

One thing to point out as far as the coil springs are concerned. For me, I like the feel of the OEM springs because they are progressive rate but I also needed a bit more suspension lift in back so I simply added $100 coil spring spacers (ones made for a Toyota Sequoia fit). An easy & inexpensive upgrade.

As for the shocks.. I'm seriously considering forking down the $$$ for replacement OEM adjustables. Mine have over 280K on them and still work.:Wow1:

 

[LaOutbackTrail]

Here's my setup:
OME Expedition Heavy coils in the rear
Stock torsion bars cranked up ~1"
KYB Monomax shocks at each corner.
33x12.50 R15 tires on the truck.
ARB front bumper and winch w/ synthetic.

I did a bit of research before purchasing, as I didn't want to do this twice. The KYB shocks came highly recommended, but still, I wanted data. I don't have the time to search for the exact numbers again, but from the research I did I found that larger bore diameter = greater cooling efficiency= more fade resistance. KYB had the larger bore, followed by OME and Ironman. Plus, information I found suggested Ironman and OME were manufactured in China where KYB is manufactured in Japan and is essentially the go to shock source for Mitsubishi and Toyota.

We had a weekend of 150 miles off pavement travel, a 700 mile round trip. A big gripe, on dips and washouts the rear end would bounce and bottom out with stock shocks. The ride was greatly improved with the KYB shocks.

As for spring setup, my truck rides level when loaded, I received many complements regarding that aspect due to the amount of cargo my truck was carrying. I do feel it would be beneficial to use stiffer, heavier torsion bars on my truck.

 

[LaOutbackTrail]

One thing to point out as far as the coil springs are concerned. For me, I like the feel of the OEM springs because they are progressive rate but I also needed a bit more suspension lift in back so I simply added $100 coil spring spacers (ones made for a Toyota Sequoia fit). An easy & inexpensive upgrade.

As for the shocks.. I'm seriously considering forking down the $$$ for replacement OEM adjustables. Mine have over 280K on them and still work.:Wow1:

The front right and back left of mine were shot... maybe I just drive harder. I've got two good shocks if you want to buy them

 

[off-roader]

One other thing if it makes any difference... IIRC, KYB is a Mitsubishi company.

The original shocks are made by KYB.

 

[CarlosC]

Thanks for the input! I appreciate it. I think I am going the KYB route. I'll start there and replace t-bars / springs as needed down the road.

Love this forum. You guys are a great help!!

I'll be posting this later (possible build thread). But, here's a peek at my recently purchased '99 2.5.

View attachment 157364

 

[SoCalMonty]

One other thing if it makes any difference... IIRC, KYB is a Mitsubishi company.

The original shocks are made by KYB.

I'm not sure if they own KYB (Kayaba before 2005, when they rebranded with the name KYB)...they were founded in 1919, and started making hydraulics for aircraft in 1927 according to the company profile. But they are certainly not some fly by night operation! They have a good reputation and a long history.

Actually, it looks like Nippon (power steering systems) is a division of KYB. I didn't know that, Nippon is a big name in Japanese cars.

http://www.kyb.co.jp/en/company/history.html

 

[aspect]

Nippon means Japan

Nippon Power Steering Co would not be the same as Nippon Denso etc, kinda like all the companies over here that are called "America/American (some product) Co" are not related.

Good info in this thread, was just considering this purchase myself, thanks.