Would you be interested in higher-rate torsion bars?

[Herbie]

Hello all, I'm in the midst of some upgrades on my lifted van and I wanted to get a sense of how many other people might also be interested in some upgrade parts.

For most of us with lifted AWD vans, the only real front suspension adjustment we've been able to make thus far is to the pre-load on the torsion bars; either via the stock adjusters, or with re-indexed keys that add additional preload. I would like to have the option to also use a higher spring rate on the torsion bars. With my pop-top conversion and camper additions, my van is already heavier than many folks. In particular, I have been hesitant to add an aftermarket bumper and winch to my van because of the additional weight that would still be borne on the OEM bars.

I am working with a company that manufactures aftermarket torsion bars for offroad and race use. They already produce a line of upgraded torsion bars for other GM trucks, Hummers, Suburbans, etc. These bars range from 15% up to 30% stiffer than stock. I am early in the process with them, but it sounds like they may be able to produce similarly uprated bars for the Astro/Safari platform.

I know that demand will depend greatly on price (which I do not yet have), but it may help things along to know if anyone here would be interested in a pair of these?

There are a lot of things to work out, but I believe such bars should provide a mild torsion bar lift over stock while using the OEM keys, in addition to being a better option for those of us running with greater weight over the front axle.

What say you?

[SportsBoy]

Cool idea!

Could be into it, but that's only if I needed to replace the stock bars for some reason.

[Herbie]

Fair enough - especially since Used and Aftermarket are the only options, now. Went looking for factory bars to use as a reference and it seems that the RHS bars are discontinued and out of stock in all the usual places.

[dcsleeper]

we could always use a new source.
so, stock, and 15% or 30% more

[markmitch]

possibly, depends on price

[gavio]

I might be interested, my van is very heavy too, what with the full camper conversion and gear....

[Rockridge]

Heavy duty torsion bars might push me over the edge to installing a plow on the van. Hmmmmm

[CopperFiremist]

Considering a new set is $500 shipped I think it would need to be around that price point and from my experience under these vans most of them that have over 200k need new torsion bars anyways. Keep us posted

[Herbie]

Just a follow up, folks. I'm working directly with the torsion spring designer now. The OEM bars have been input into CAD as a baseline, and we're talking now about next steps.

I have learned a few things that I want to gauge people's reaction to.

1) They can certainly make a thicker bar and keep the factory "clocking" arrangement for both hex-ends. However, this can sometimes get into problems where as the spring rate increases, we might need *less* pre-load on the keys, and it is possible to run out of adjustment range. This makes it difficult to offer a big range of spring rates, because they would need to tune the clocking of the bar-ends to each spring rate.

2) Their usual solution for this is to instead manufacture the new bars such that the aft-end is splined, rather than hex. The bars are sold with modified adjuster keys that have matching splines cut. This gives essentially infinite adjustment on the clocking and preload (and also makes things easier to install), and allows them to sell torsion bars at basically any spring rate desired. Obviously this increases the cost, though. They're currently selling similar kits (bars + splined keys) for other GM IFS vehicles for $1300 - $1400.

Given my plans for my van, I still think this is worthwhile (and especially so for anyone with an AWD-based Class-B conversion, Tiger's etc.), but I want to be able to give an honest assessment of how this might affect demand.

I will keep this thread updated as I learn more, but I'd appreciate comments from anyone with opinions. If this pushes you into "too rich for my blood" territory, that's good info too.

[AstroWill]

Just a follow up, folks. I'm working directly with the torsion spring designer now. The OEM bars have been input into CAD as a baseline, and we're talking now about next steps.

This is awesome! Definitely something that has been missing from our 'options list' for a long time now.

$500-600-700 would be in the 'take my money now' zone for me.

Would be so much cheaper if we had a standard size from another vehicle. I was just looking at a set of Dorman replacements for our van at just under $400 shipped, but with the thought of going v8+winch bumper a heavier duty spring sounds like a winner to me.

But custom = expensive, gotta pay to play.

[MechBob]

Very good stuff.Will throw out some things.GM dropped the old longer bars,to the newer ones,because of so many failures.Consequently,the shorter bars are a bit stiffer,and most people like that."Rate" will not be adjusted by adjusting the key links,only the ride height.I have never seen a adjustable,or progressive rate torsion bar,as you can do with coil springs.Therefore,they should offer several options,for,as said above,v8 conversions,winches,plows.The only way to change the rate of a torsion bar is thickness and length.Finer splines are great,for leveling a van,VW and many others used this system for years,but does have a drawback,they strip out under high load.Perhaps a replaceable,keyable insert like SuspensionMaxx makes would be better.I could see a market for 2 bars/systems, one for mostly stock vans,slightly heavier,and a heavy bar/system, for the v8/winch,plow,heavy bumper guys.

[MechBob]

oh,don't get me started on longer a-arms,and remounting them on the frame,lol real expensive.But,yes,i would be interested in a slightly heavier bar for one of my vans.

[Mastertechpat]

Before I spend that kind of money I would do JOR solid front axle swap

[Herbie]

That's a legit position - do we know what the pricing on that option is yet? Last I checked it was just sort of "coming soon".

I'm still headed down the IFS path due to both the time I spend on pavement and the fact that I like being only modestly lifted, a SAS option would put me up higher than I need/want to be.

[Mmusicman]

1) ..as the spring rate increases, we might need *less* pre-load on the keys
2) Their usual solution for this is to instead manufacture the new bars such that the aft-end is splined, rather than hex..

True. This totally works! Correct that adjustment does not change "spring rate".. and that the splines would simply allow for smaller increments of preload, which would give you a better ability to choose your ride height based on heavier spring rates, unknown loads, and unknown results. Currently you have to buy reindexed keys to accomplish a similar goal, typically good only if higher lifting is desired.

Great idea.

Unfortunately, I don't think it's practical or necessary. Most of the van's extra load is "usually" carried by the rear springs... and you can already somewhat adjust fronts if needed. Motor weight won't change, or not enough to matter. When loads are applied far enough to rear, the front actually lifts (I've taken measurements). If the weight is centered, then there might be some need for increased front load rate, but it wouldn't practically be by much.

I just don't see enough need or practical use for it.
Cost is certainly a big factor too.
But there certainly could be some less common applications.
And certainly it would be specialized equipment with a limited market.

[MechBob]

Hey,MM love your mod vans,and your great info,here.But your post seems to ignore lots of other van owners.yes,you have great vans,great mods.Ever go off road?Sand does not really count.Go into the mountains. Go into the desert. Find some rock ledges.OK,made my point.As far as the slightly heavier front torsion bars,look at all the posts that show the new,young generation,buying the old astros,and modifying them.Forwarding front bumpers from jeeps,winches,anything that protrudes forward makes the load of the front end,by a high ratio,very much higher.Which makes the load on the torsion bars 30% or more higher.Time to go with the flow,youngsters are taking over.Lets help them