Coil spring advice

[02-SR5]

Need some help on replacing my HD OME springs.

My car is currently sitting at 600mm front and rear. I really like the hight, the clearance and ride, but I am unable to fit the front bump stops.

I'm thinking of fitting King HD springs to lower the ride hight.

Can anybody recommend King springs?

[BMN]

I run kings in the rear of the Challenger and always use them in the race car for both rally and tarmac and have never had any issues. IMO you should be aiming for EBH of around 560-570mm and cutting down and reshaping the bump stops about 10mm and refitting. This should give you some lift, but more importantly correct droop when required offroad. Note the shape of the bump stop is important as it acts a little like a variable rate spring.

[Ent]

Mark King of Kings Springs is great to deal with and his product is good. He calculated and wound a set of custom rears for my PC that achieved a rear EBH of 577mm with full tank, light truck tyre spare, and me on board. The free height is 420mm so more than enough to retain the rear springs with the 535mm Bilstein dampener. The wire is 16mm with a tail of 10mm in order to compress lower than the bumpstops, so they, rather than the spring take the full compression hits.

Mark, due to a lot of mucking around, has the full measurements for the PC Challenger rear, plus a set of original Challenger rear springs. So, if the above is not to your liking then Kings can custom make a spring to match your requirements. He got mine to the exact mm of EHB, which is no mean feat. But be wary, as the above was the only combination that gave extra free height and still fully compressed block height to allow the bumpstops to work as per factory design.

The ideal solution for the front is adjustable coil over design. At this stage only Drummond Motor Sport do this, but I have a feeling that maybe another mob do it with Koni dampeners, but not sure. Ironman are heading this way but nothing yet for the Challenger/Triton.

While Drummond are far from my favourite mob to deal with there is nothing wrong with their product apart from having no provision so bolt the sensor wire to the strut. 50-60mm hose clamp solves that problem. They make two spring rates, 650lb and 800lb. The latter is designed for bulbar/winch/spare battery setup but I found even on a standard manual they work brilliantly. Been adjustable bases they can be adjusted from standard height to plus75mm. A trick is to jack under the wishbone to get enough clearance to swing the supplied spanner if they are setup for standard height. The hidden joy is you can fit them first and the later add a bull/bar winch plus spare battery, then with a lot of grunting re-adjust for the lost ride height.

I brought the dampeners with adjustable dampening rates but have not played with them. Drummond do a cheaper set that are not adjustable on dampening rate, and they are probably a better option, if dollars are important. By all accounts the adjustment range is not great with Drummond dampeners, but they are pretty much on the money to begin with.

I find on the Challenger that the dampener quality is much more important on maintaining good ride than spring rate, say up to 17mm wire on the rear. In fact, I find the rear Bilsteins rather poor in comparison to the Drummond rear dampeners. But the Drummond dampeners were the wrong length plus their bulk fouled the brake lines so they are not offered, as they are just not suitable for the Challenger rear.

I aimed for an EBH of standard plus the allowed +20mm tolerance and at +5mm crib factor to allow for future sag. So 567mm front and 577mm rear EBH. If you run R16, then unless you plan snowchains, or need to strictly adhere to VSB14, the 75 profile work a treat. They give an extra 13mm in ride height. So with the above the front centre clearance is 267mm and rear 230-5mm, as the rear diff can only be raised by taller tyres. I find off-road the issue of clearance is more with the rear nowadays. When with factory suspension the front was the bigger problem.

On road the above works extremely well with four up or just the driver. Off road articulation is as good (actually on the rear slightly better) than standard. The Challenger can “roll” over large rocks when crawling without “collapsing” onto them. At higher speed the suspension soaks up ruts and pot holes nicely.

I go bush with two on board and around 50-60kgs of recovery gear up against the rear seat. Very impressed with performance, as the Challenger can now tackle medium 4wd tracks with ease, and more importantly no damage. The rear is the issue as the standard towbar is rather poorly placed. But replace the anti-rattle bolt with a round headed cap screw, move the plug onto the top of the towbar, then get a new retaining pin from Hayman Reece that “hides” in the towbar and you have very solid protection for the spare tyre and rear panels. Rather frightening thumps still happen but no damage.

While been a hell of a journey as you may have gathered that I am now very happy with this setup. Would like to replace the Bilsteins with Konis but Koni do not do a set for the rear. My aim was to maintain road behaviour and tackle medium 4wd tracs without damage to the vehicle and the above has worked a treat.

Bumstops are retained and are as per factory.