Thread: Koni Raid shocks with full air suspension

Originally Posted by rar110

Thanks for detailed post.
Would the 90-5375 standard height Raid rear shock resulted in less modification?

You could use those shocks but because they are shorter you would have to lower the shock mount even further which would rule out the simple solution I used.

Originally Posted by Bush65

With the shortened spacer between the air spring and the spring perch, take care that the bellows doesn't rub against the spring perch, which is a little too narrow in that area. In service, the bellows will expand more that is when static.

I understand you don't want your "standard" ride height too high. If you raise the ride height when "off road", you will find that the extra volume of trapped air in the spring will improve the ride.

Does your control system allow different programmed height settings?

Yes your right about taking care the bellows wont rub, I did consider this and if you take care to center the bellow there seems to be enough clearance. And I must correct the amount I shortened the spacer, it wasn't 15mm, was more like 12mm. The standard spacers measured about 63mm +- a few mm as they wern't square, I cut them down to 52mm.

Interesting you find a raised ride height gives an improved ride, I find the ride gets firmer with more air pressure in the bags. Must admit I haven't tried the raised height with the koni's yet, will have a play.

I have the accu air e-level controller, allows 3 height settings.

Originally Posted by Dougal

Thanks for all the info. Do you know the length and stroke of those konis?

Don't have the lengths at hand but the strokes as follows;

Front = 220mm

Rear = 206mm

Funny how the fronts are for 0 - 50mm lift and rear is for a 40 - 60mm lift and the fronts have a longer stroke. I'm pretty sure the other rear shock for 0 - 40mm lift has the same stroke, is just a bit shorter in the shaft.

Originally Posted by taylorslandy

... I'm pretty sure the other rear shock for 0 - 40mm lift has the same stroke, is just a bit shorter in the shaft.

Same stroke as front shock or raised rear shock?

Originally Posted by taylorslandy

You could use those shocks but because they are shorter you would have to lower the shock mount even further which would rule out the simple solution I used.

Thanks I get it now. And the two types of rear shocks have the same travel.

This thread is timely as my rear Bilsteins are finally wearing out.

Originally Posted by rar110

Same stroke as front shock or raised rear shock?

Same as raised rear shock. The raised rear shock has a longer shaft, not stroke or travel.

Originally Posted by taylorslandy

...

Interesting you find a raised ride height gives an improved ride, I find the ride gets firmer with more air pressure in the bags. ...

Many people make the mistake thinking that to increase the ride height requires more air pressure.

When the ride height is within the range where the bellows is rolling on the nearly parallel section of the piston (BTW this will be around about the Firestone recommended ride height +/-), there is very little increase in pressure required to increase the ride height, and the change in ride height occurs because the volume of air trapped inside the air spring changes (increase volume to increase height).

When the ride height is lower than recommended by Firestone, and the bellows is rolling on the flared base of the piston, then the pressure will need to increase to extend the air spring because the effective area is reduced as the bellows rolls up to a smaller diameter section of the piston.

However if the load is increased the air pressure needs to increase.

Below are some figures based upon the Firestone air spring assembly W01-358-5712 with bellows 1T14C-7. This is a little different to your rear air springs, which I believe may be W01-358-5422 with a 1T14C-3 bellows, but will be close enough for the sake of this discussion (take a bit off the ride heights for the shorter bellows). One reason for using this air spring is that I have the Firestone data sheet for it. The calculations to obtain the data are based upon those given in the Firestone design manual/guide.





Consider first a load on the air spring of 1200 lbf (544 kg), and the following ride heights:

a) 10" ride height, 34.0 psi air pressure, 339 lbf/in spring rate
b) 11" ride height, 37.5 psi air pressure, 277 lbf/in spring rate
c) 12" ride height, 38.4 psi air pressure, 192 lbf/in spring rate
d) 13" ride height, 38.4 psi air pressure, 170 lbf/in spring rate
b) 14" ride height, 38.9 psi air pressure, 169 lbf/in spring rate

Consider first a load on the air spring of 1750 lbf (794 kg), and the following ride heights:

a) 10" ride height, 50.1 psi air pressure, 443 lbf/in spring rate
b) 11" ride height, 54.4 psi air pressure, 348 lbf/in spring rate
c) 12" ride height, 54.7 psi air pressure, 239 lbf/in spring rate
d) 13" ride height, 54.7 psi air pressure, 227 lbf/in spring rate
b) 14" ride height, 55.3 psi air pressure, 244 lbf/in spring rate

Note: I have highlighted the row for 13" as that is the recommended ride height for this particular air spring. The static ride height for a stock Defender rear coil is generally around 11" to 12".