Linear to progressive springs, which rate?
 

My current setup works quite good for the moment, however, soon, I'll try some progressive springs. Curious, you know...

Is it a good idea to try some springs with approx. the same stiffness, as the linear ones I'm using now?

In addition, I like to using sway bars. Is this good with progressive springs?

what are liner and progessive springs? :confused: I just use the ones that AE sells...

Re: Linear to progressive springs, which rate?
 

Cole Trickle, I might be wrong about this but I believe the HPI progressive springs are stiffer than their linear springs. As far as using sway bars with progressive springs? There's no certain way you have to setup a car. It's all about setting up a car that works for you. For example, you might want your car to have alot of steering coming out of a corner where I want very little steering coming out of a corner. Sure you can use the progressive springs with sway bars, will it work for you-only you can make that decision. Happy racing and good luck!

ahhh. an interesting thread. some months back i did some testing on hpi's progressive springs. here's what i found.
as you may guess, they are not a progressive rate, but a dual rate. look at the coils. just two different spacing between coils. i've found hpi's published numbers to be an average of the two spring force constants. through the first 1/4" of compression is the lower rate, and at about that point the smaller coils are compressed and the second, stiffer rate takes over. i tested four whites and four yellows and my spring dyno. all numbers were very consistent. i have the graphs somewhere. it makes some sense though, as touring shocks are rarely capable of compressing in excess of 1/2". given the fact that the first half of that is a softer spring constant, i would run something a bit harder than typical. i can't remember the percent difference between the two rates. ummmm for the yellow, i think 19.5 rating, the two rates were like 14.5 and 24. so you can see why your car may feel soft without compensation.
sway bars my be a bit much as they come into play when the arms are at great differences, thus meaning one is highly compressed. with the stiff spring force at that point, plus the added force of the sway bar, you car may become unpredictable. don't forget that a sway bar will kill your droop effects durring cornering. just a thought. hope this helps a little.

I'm running yellow and orange HPI springs. The white and yellow progressive is very very close to my current springs (+- 5 g/mm).

Sway bars killing droop? Hmmm, my car still has a lot of droop (haven't measured it yet). But you're probably right, because when the car rolls.... However, I find that using a little softer springs than I else would do and then add swaybars, gives a very consistent handling. But it sounds like, I should try progressives with and without swaybars.

Interesting point, that the HPI springs are dual rate, rather than true progressive.

But I dont think I'll go further with this experiment right now. I'm close to buying a new car instead. The Mission. But I would like to discuss progressives anyway....

Thanks for your input.

mr trickle,
yeah your right. the droop will still be there in terms of measuring, but not as evident on the track. i agree with the light springs and sway bar in theory, but i've gone without it most of the time, as i'm still learning to find good setups without adding that variable. gets complicated quick.

btw - that mission is a champ. i have the old 99 pro and i just love schumacher cars. solid every time. i'd love to get that mission, but i ran into a cheap kxone and that's my newest baby. gotta control myself. ok later.

Talk about self-control; My situation unfortunately changed, so I'm forced to spend my money somewhere else. Maybe later, I'll get The Mission.

I like the handling with sway-bars, really smooth and consistent roll in the corners. But I'm also running with a one-way pulley, and the softer springs introduce more front-rear weight transfer, so the difference between on- and off-throttle are very big right now. Too much for my taste, but I still have to play with droop, so maybe I can get it to work. And I also have to train my trigger finger....

Now that I have dropped the new car for the moment, I'll probably try the progressive ones soon. Depending if I succeed with soft springs / sway bars...

Hey Seaball, what do you think of the KX-One? I really like the design and basic idea, but I think the car has too little adjustements. Missing droop, rear toe, caster, anti-squat and kick-up. Sad, it can't cost much for estra hubs etc.

Sway-bars killing droop; I wont call it kill, it's more limitation in some ways.

Sway-bars are recommende on pretty smooth tracks, so here you shouldn't need a lot of droop. In side to side roll, the sway bar aint active at first, so in the beginning of the roll, you'll still get some droop effect. Acceleration/braking, that is front/rear weight transfer, the droop ain't limited of the sway bars. Besides, it depends on how hard sway-bars, you're using.

Progressive springs; Since the HPI progressive springs, more likely are a dual rate spring, I assume, they'll allow some roll pretty fast, after that the roll is limited. To me, it sounds nice, get some extra traction fast when cornering, without too much roll, slowing you down. I have to try that sometime !

cole
 

hey man,
i guess i bailed on you. the thread got lost. anyway, i like the kx one. i've been running it a ton lately. i was, at first, infatuated with the engineering behind it. now...i dunno. it drives well, but it has such a high cg, that it stays on its lid like half of the time. we run with those take off dots and if you cut a corner with the kx and nip one, it rolls over. incredibly frustrating. and yes, it's lack of adjustability is lame. with the ladder frame, it would have been nice to see an xray like antisquat adjustment. and extra caster and toe blocks should be included for $360. the droop thing is tough with the ladder chassis, but yes, some design changes and it could've been incorporated. the worst part is the kit screws. i think they are made of lead. the phillips strips before the car is even built.

overall, i'm not too pleased. the steering has too extreme an ackerman angle, the car is scarcely adjustable, the included servo saver is too soft, and so is the kimbrough counterpart, forcing me to run rigid steering, thus, losing a new (30 runs) 9402 tonight. the kit screws are garbage, much like the one way that goes before the tenth run. tc diff balls are not available and my diff won't stay adjusted. oh yeah, and the kit shocks are dual damping. heavy upon compression and light upon the return. a neat idea, but there's a void of damping in between that just irks me. plus it's tough to cross referrence normal shock settings. it is .... impractically exotic.

but i have a schumacher, so i have high standards. i just can't get myself to run my new graphite chassis on asphalt, or the kxone would be retired.