Still looking for more control (ie stiffness) in the rear, to match what I have up front. Re:The current/previous setup


This is also something of a follow up to the KYB:Gas-a-just v GR-2 thread,
and I have been schooled once again that the KYB Monomax is (likely) a performance spec above the Gas-A-Just.

I did just now finally acquire a pair of Bilstein AK1089's for the rear, but am severely disappointed.


Shockingly the Bilsteins are not high pressure, and judging by my informal rate test, not significantly different than the Gas-a-Just.
I will not even install them because, even at a premium branded price, they could actually turn out to be inferior to KYB GaJ, also a low pressure shock.

So, when I get on this yet again, I am likely in search of a KYB Monomax, for the rear.
AFAIK, this app is not in the catalog, so I will be on the look out to borrow something from another app.

Unfortunately, the auto industry publishes ABSOLUTELY NOTHING USEFUL about any aftermarket products.
Naive attempts to research via the supply chain routinely put me in contact with grade school drop outs.
If I ever would get through to tech support, it would seem their product had been design by an alien species on another planet, who btw don't publish specs either.
If I push to get hold of a real apps engineer, then I get reminded that I'm not a major distributor oem with factory contract standing.

I can obviously get end-to-end dimensions on the available Aero rears.
If I get super ambitious I could, in theory, build a jig to measure the damping rate(s) on the KYB GaJ.
Beyond that, it could get even more expensive buying a survey of Monomax shocks, just to measure test and reject.

Would sure like to know if anyone had a confirmed KYB part that works.

My other option is to grab some adjustable shock that has compatible dimensions and could, in theory, cover the rate range in question.
It would also be expensive, but not any more so than the trial-and-reject path that I'm on (Re:Bilsteins).

** Bilstein AK1089 dims **
18.0" bolt centers
12mm id x40, top bush
12mm id x38, bottom bush

 

have you checked with KONI ?

 

Precise answer, no.
But that is exactly where I will go if I can't fish out from the crowd a solid referral on a Monomax.

I'm actually famous on a BMW forum for my trick retrofit of adjustable Koni's in place of factory assemblies that cost $1K per corner.
And I have Koni's front & back on the mbz.

Just a rule of thumb, Bilstein is image centric while Koni is apps centric and, contrary to my schtick which is true 98.5% or the time, Koni does provide some info and has been known to work with developers.

 

I tried KYB in my 1986 Aerostar, they were terrible shocks, they rattled my suspension, no "finesse" at all. Then I tried Gabriel, not much different but slightly better.

I have used Bilstein in a 1979 Saab 900 Turbo, they always leaked. They are over-rated and over-priced.

my best experience has been with cheap shocks from Monroe which I presently use in my 1997 Aerostar.

In my Jags, Monroe preserve the soft ride. I've never used Koni.

 

I don't think KYB makes a monomax for the Aerostar. Did you find one that fit the front?

I had Monroe Sensatrac on my van, but I think they lost a lot of their damping in a matter of months. They allowed the van to wallow like the worn out stock dampers. I'm now using KYB Gas-A-Just, and they are noticeably stiffer, and provide much better motion control than either Monroe or stock.

If your budget will allow, you can look at QA1 products. They have an adjustable damper with stock style eyelets that's close to the size you need:

https://www.summitracing.com/parts/qa1-ts709/overview/

It's for an old Chevy C10, with compressed/extended lengths of 12.8/19.5 inch. Do you happen to know the compressed length of the Aerostar damper?

Or you can download their catalog, which contains parts and accessories to build a damper to your exact specifications:

QA1 Catalog Request & Download | Drag & Street, Circle Track & Industrial Catalogs

 

To start with, call KYB, they have a great group ot techs who are there to help..........

secondly, I almost chuckle when I see postings that say ONLY THIS SHOCK, or THIS SHOCK IS TOO STIFF, etc.......it is all dependent upon 1 thing "what type of feel does the owner want" and final shock determination is based upon 3 factors:
1. Tires (specific construction)
2. Springs (rate & design including progressive style)
3. Road conditions
1) Koni- Excellent for racing applications- overpriced for street applications
2) Tokico, QA1 & Bilstein- A very good shock for street/strip applications. If you are running very stiff tires on the street (such as Bridgstone or tires with profiles shorter than 50 series), these provide the extra give that you need for both comfort & stability....but Bilstein has had a lot of QA issues over the past several years so IMHO, I would avoid.
3) KYB- A very good shock for street/strip applications. If you are running a softer tires on the street (such as BFG or tires with profiles not shorter than 50 series), these provide the extra stiffness that you need for both comfort & stability. The Exel-G’s (formerly GR-2) are the equivalent to the Edelbrock IAS automatic adjusting units. Overall, stiffness between the Gas-a-just and the GR2’s are the same, the difference is the GR-2's valving which stiffens things up from a oem setting to that of the Gas-a-just units.. Best shock for the $/best price typically found at Performance Suspension Technologies (PST) and typically about 1/3 less than Bilstein.
4) Gabriel- A very nice good quality HD OEM replacement type unit.

 

Yeah, up front I've been using the 565051 for several years.
Interestingly, just now when running a google on the number rather than googling say "Aerostar Monomax rear" I came up with their dimensions page.
I then ran a test of the chart using dims off the current shocks and did in fact come up with an Aerostar rear, only it was in their Excel-G line, #344290.
The Gas-A-just KG5492, also shows up in the list, with slightly shorter dims.
Haven't seen anything else in the length, end style, and eyelet dims.

 

Tokico dropped production of shocks for the Aerostar about 15 years ago. Think I got about the last set in the US. Handled well with my HD mudder tires on the Aero.
Been running KYB GAj's the last few sets front and rear. Nice riding highway shock with reduced body roll in fast vehicle steering movements and less rear wheel hop bounce on bumps and holes. Dampens well. Lasts well, good ROI.
Tried 1 set of Bilsteins years ago, rough uncomfortable ride. Took them off and gave to another Aero owner.

Stock OEM FoMoCo shocks and Monroe's = garbage, short life for effort to put on.

I can raise the rear end ride quality to miserable by raising the rear air bags to 20 psi, gut bouncing spine crushing ride.
At 5 psi with no extra load, rides much like light truck F150, and level front to rear. Hate that nose up tail down and dragging butt stock Aero look.