Thread: Problem With Dobinson Disco Coil Springs

I got a set of Dobinson front and rear springs for my Discovery 1 (C51-016 and C51-023V respectively). Dobinson lists these as standard height replacements with higher spring rates. Upon installing them the rear of the car seems to have been raised substantially and the front remained the same or possibly even dropped.

Dobinsons' sales reps and literature claimed the springs would be 20% stiffer and 20mm taller (which I figured by the time they'd sagged a bit and had the extra load of the accessories on the car on them would be about the same as stock).

I don't have the measurements from the hub to the top of the wheel arch from when it had the stock springs in, but with the Dobinsons it measures 510mm and 470mm in the front even on both sides. Correct me if I'm wrong but stock new, wasn't the hub to wheel arch clearance 470mm all around? If so the Dobinsons 'stock replacement HD' springs have boosted me 40mm in the rear and kept me the same up front, despite claiming ~20mm increase.

The stock springs measured ~385mm and ~395mm for the rears and 390mm and 400mm for the fronts (sorry I don't know which ones came off which side as I wasn't there when they were). With the car up on a lift and all the weight off the suspension the new Dobinsons units were 400mm on the rear (though they were still slightly compressed) and 350mm (uncompressed). So the new rears are about the same length as stock (fine by me), but the fronts are dang near 50mm shorter. Though in both cases the bar is noticeably thicker.

According to Dobinson's the fronts (C51-016) are supposed to be 370-380mm in height/free length and are 200lb/in rate, the rears (C51-023V) 415-425mm and are variable rate (the guy couldn't answer what rates they vary between, but it's definitely more than stock).

So that means my fronts are about 20mm shorter than what they're supposed to be.

The car has a steel TJM bar up front (no winch) and a dual battery setup, the rear has a roof rack over it (which ends before where the roof slopes down) two Jerry cans of fuel, tools, spare parts, camping gear, for and water, clothing and personal items in it (so not light but not super heavy either). Like this the rear sagged and the front sat proud (like it was at least still at stock height).

I've attached a photo of the stockers. Hopefully the paint codes on them can be made out, but in case not two are green and brown striped one is brown striped and the other white striped. And how about a picture of one of new springs and shocks too.

I'm fixing to head off on a big trip and don't have time to go up to the store where I ordered them from to have this sorted out and I wasn't planning on coming back here but rather traveling on to Western Australia for the remainder of my time in country. Not sure there's a way to get this taken care of aside from buying spacers and trying to ignore the fact my springs aren't what they're supposed to be.

Originally Posted by Tombie

That will be interesting. Corrugations kill foam cell shocks pretty quickly and they often don't come back when they cool down...

The bit of research I've done leads me to believe that foam cell shocks will stay cooler and resist fade longer than an equivalent quality gas shock in a given situation, but once ran hot will not return to their previous level of performance upon cool down whereas gas shocks tend to only see a slight loss from initial performance once cooled down (until you step up to Bilsteins and a few other primo brands which experience almost zero to no diminished performance).

Long stretches of serious corrugations at speed are hell on all shocks, not just foam cells. And while foam cells will generally resist overheating better in that situation, they just don't bounce back from it like gas shocks. If not subjected to extended periods of high-speed corrugations or continuous full stroke travel (presumably at low speed) then foam cells SHOULD yield good performance and reliability in relation to the price point (moar moneh equals moar betta, right?).

Anyways we'll see how these go. I don't plan on trying to take the corrugated sections at highway speeds. Even with great suspension I hate subjecting a vehicle to that, and I don't dare do it to this car as precarious as it seems to be towards such treatment. And serious suspension flexing over extended periods isn't on the agenda either. So hopefully they survive and prove their value. If not, well at least they have a 3 year 60,00km warranty.