Spring preload?

[ChargeR]

How does the car handle and feel?

I would have thought having the springs loose like that would decrease the stroke of the shock and make it handle/feel worse.

I find it interesting that MCA recommends lowering via the spring seat.

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Apart from the legality concern to be aware of that tinker raised above, I can understand why MCA could advise that process. If they've designed the shock with sufficient travel and provided a bump stop of the appropriate length to prevent metal to metal or tyre contact at full bump, then lowering the car with the spring perches is totally fine as the shock is still well within its stroke, and has the advantage that the bump stop says in the appropriate point in suspension travel to prevent something else contacting.

The great majority of real racing shocks are setup like this, though quite often with a helper spring to keep the springs on the perches at all times. Build the shock to the correct length, fit a bump stop of the correct height, and you'll never run out of travel in either direction. It's only since the Japanese shock manufacturers started pushing that you must have "base height adjustment" that everyone seemed to start thinking it was essential. I suspect it was mostly so they could get away with using a shock with less travel....

[tinkerbell]

Got a link/reference for the legislation that states all springs must be captive at full droop?

the legislation is Motor Vehicle Standards Act 1989,

which is the basis for the Third Edition Australian Design Rules (ADRs),

which are the basis for the National Code of Practice for Light Vehicle Construction and Modification (NCOP),

in particular, the NCOP Section LS "Tyres, Rims, Suspension and Steering" (Version 2.1 – 1 November 2015) states:

If coil springs are lowered, or replacement lower coil springs are used, they must have the same end shape as the original springs. They must retain some pre-tension and not come loose when the suspension is in its lowest position (full rebound). They must have clearance between coils at full bump. (p.27.)

https://infrastructure.gov.au/roads/...ov_2015_v4.pdf

[MCA Suspension]

Hi Guys

I'm Josh Coote, I'm the guy behind the Red/X/Blue Series suspension for MCA Suspension. My father started the business about 25 years ago. I was working for him for about 4 or 5 years and then started doing my own line of products which is the Red/X/Blue Series which has been going for just over 3 years now.

Unfortunately I don't get much of a chance to frequent too many forums .. so if you have any questions for me please contact me either through my email redblue@mcasuspension.com or through our facebook page "https://www.facebook.com/mcasuspension/". That will guarantee quicker replies.


IN REGARDS to this topic though.. ChargeR has pretty well nailed it on the head. And Tinkerbell.. that rule is about replacement springs only.. not full replacement units.. as it also says there that the springs must retain the shape of the original springs.. which would make pretty much every set of aftermarket suspension illegal as most use a narrower spring design than standard and a different top and bottom spring mounting style.


But going onto why we do it the way we do it.. The bottom mount not only controls the cars height, but also the wheel travel range. That is the highest and lowest position the wheel can move in the wheel arch. Moving the bottom mount also moves this travel range up and down compared to the car. This is why some people have problems with wheels traveling too far upwards and causing scrubbing issues or even worse, suspension arms hitting chassis or something like that.

We have set the bottom mount position after doing a thorough setup with each model we have products for. So we have set it up so that the wheel can travel up as high as possible but stop just before any contact issues are made, and still have enough wheel drop for most ride heights. So yes adjusting the height via the spring seat will change how much travel you have, decrease if you lower, increase if you raise.. however you want this to be the case when the suspension is setup correctly, as there's no point in having more suspension travel from your ride height than what the car can physically deal with.

And then onto the next question of.. but wont the spring come loose? Well no, in 99% off cases when driving the car the springs will not come loose. This is because the springs are still compressed somewhere between 20 and 50mm or more depending on the setup, so you have this far or more (depending on the motion ratio) of wheel movement before the springs even think about coming loose.. Now in most of our setups we're able to fit Spring Locators which help keep the spring located side to side even if they are loose.. however in same cases like the EP3 and DC5 we can't use spring locators in the rear due to the rather unusual top mount design. But there is still a very minimal chance that you'll have any problems... basically I havn't been made aware of any at all. We can supply helper springs.. they are $100 each including the adapter though.. and they do take up about 12mm or 15mm or so of space for height adjustment.. and there's already not much room on the backs of EP3 and DC5.. but they can be fitted in most cases.

And the other FAQ would be "but wont the spring rate change if you preload or loosen the spring". The answer is no.. the spring rate or "spring rate of change" can not change for Linear (normal, non progressive) Springs. 5kg/mm means that if you want to compress the spring you need 5kg.. and then if you want to compress it another mm you need another 5kg.. and that is a constant. So the spring rate can't change. And realistically no matter how much you preload the spring, the cars weight will compress it further, and so because the same amount of total weight is coming down on the spring, the spring is sitting at the same length at ride height every time. And so as far as the car is concerned, it's sitting on the exact same spring setup at ride height.

There's hopefully some helpful info to start with.

Regards
Josh

[tinkerbell]

Hi Josh, thanks for dropping by, I note you state:

that rule is about replacement springs only..

however, I am pretty sure the implication is that all springs must be captive at all times.

this is supported by the QLD Transport and Main Roads publication regarding "Minor Modifications":

http://www.tmr.qld.gov.au/-/media/Sa.../G19.pdf?la=en

which states:

Lowering or Raising of Vehicles
A vehicle’s suspension can be raised or lowered by 50mm without specific approval, provided:
• at least two thirds of the original suspension travel in either direction is maintained
• coil springs remain in locating seats on full suspension droop
• the normal relationship between the front and rear suspension heights is not unduly affected
• replacement springs have the same or greater load capacity as the original springs
• suspension coil springs are not shortened by cutting or heating
• leaf spring suspensions are not raised by the use of extended shackles, adjustable metal plates or by placing the leaf springs to the opposite side of the axle
• if lowering blocks are used, they are either steel or aluminium
• the vehicle maintains a minimum running clearance of 100mm and the requirements in Australian Design Rule (ADR) 43 are met*
• the suspension of a vehicle fitted with Electronic Stability Control (ESC) may be modified without certification provided it is not combined with any other lift (i.e tyre and suspension, suspension and body block, etc).

in regards to the current car's situation - does it concern you that your product was installed so badly? they look like great parts, but a good part is only as good as it's installation!

[eskimo_firefighter]

Thanks ChargeR and Josh from MCA for your thorough explanation. Great info in this thread.

[MCA Suspension]

Hi Josh, thanks for dropping by, I note you state:



however, I am pretty sure the implication is that all springs must be captive at all times.

this is supported by the QLD Transport and Main Roads publication regarding "Minor Modifications":

http://www.tmr.qld.gov.au/-/media/Sa.../G19.pdf?la=en

which states:




in regards to the current car's situation - does it concern you that your product was installed so badly? they look like great parts, but a good part is only as good as it's installation!

Tinkerbell, that link doesn't seem to work for me.. can you please post up another one that will? I've not seen this mentioned in the ADR rules before and am interested in finding out.

In saying that though.. if you think 95% (if not 100%) of other aftermarket "coilovers" out there are 100% ADR compliant, loose springs or not then you're mistaken. What I'm saying is that you only need to not be compliant in one aspect and they aren't ADR legal. And I know you're not saying that every other brand or even most or some are legal and ADR compliant.. however the fact that mine "may" not be due to loose springs does not mean they differ from the rest which are most likely non ADR compliant for other reasons. So the legality makes no difference when comparing to other options. Plus simply adding helper springs fix the issue 100%.

Most aftermarket "coilovers" will generally lose out to the rule stating that they must retain 2/3s of the bump and droop travel of the factory shocks.. a lot of other "coilover" setups would struggle to be 1/2 of factory... and in my opinion this is far worse than having your springs become unseated when the car is jacked up off the ground.

[ChargeR]

Most aftermarket "coilovers" will generally lose out to the rule stating that they must retain 2/3s of the bump and droop travel of the factory shocks.. a lot of other "coilover" setups would struggle to be 1/2 of factory... and in my opinion this is far worse than having your springs become unseated when the car is jacked up off the ground.

Agree 100%, it's unfortunate that the writers of VSB14 have been so prescriptive in their requirements. There's many ways to build a safe vehicle outside the VSB14 requirements.

the legislation is Motor Vehicle Standards Act 1989,

which is the basis for the Third Edition Australian Design Rules (ADRs),

which are the basis for the National Code of Practice for Light Vehicle Construction and Modification (NCOP),

in particular, the NCOP Section LS "Tyres, Rims, Suspension and Steering" (Version 2.1 – 1 November 2015) states:



https://infrastructure.gov.au/roads/...ov_2015_v4.pdf

Tinkerbell, the Motor Vehicle Standards Act is a federal law which applies only to a vehicle being supplied to market in Australia, not existing in-service vehicles being modified, and is irrelevant.

Similarly since there is no Australian Design Rule that places any particular requirements on coil springs, for this discussion the ADRs are also irrelevant.

Neither the Australian Design Rules nor the Motor Vehicle Standards Act make any mention of Vehicle Standards Bulletin 14 (VSB14).

VSB14 does state what you quote, but that doesn't make it law. The VSB 14 content must only be abided by in a particular state if that particular state has acts/regulations which state that, as modification of in-service vehicles is solely the responsibility of each state government. VSB14 is not law in NSW, however it is written in to the Victorian Road rules:

(3) A person who modifies, or adds components to, a vehicle must ensure that—
(a) if the vehicle complied with the standards for registration immediately before the modification or addition, the vehicle continues to comply with those standards; and
(b) for a heavy vehicle, the modification or addition is certified by a person appointed as an authorised officer under regulation 7 as complying with the NHVR Code of Practice for the Approval of Heavy Vehicle Modifications; and
(c) for a light vehicle— (i) the modification or addition is certified by an authorised officer as complying with the National Code of Practice for Light Vehicle Construction and Modification published by the Department of Infrastructure, Transport, Regional Development and Local Government as Vehicle Standards Bulletin No. 14;

It has also been adopted in Queensland relatively recently.

You shouldn't make misleading generalisations.

[tinkerbell]

You shouldn't make misleading generalisations.

but it's OK for product manufacturers to do so?

"uncaptive springs are perfectly fine"

[tinkerbell]

Tinkerbell, that link doesn't seem to work for me..

http://www.tmr.qld.gov.au/-/media/Sa.../G19.pdf?la=en

it's a PDF - you download it.

if you think 95% (if not 100%) of other aftermarket "coilovers" out there are 100% ADR compliant,

i have run Cusco, Tein, Hypermax & Koni combos...

none of these would have passed an engineering evaluation in the state i had them set...

in fact - 95% of my car probably wouldn't have!

but i was making informed decisions about running the equipment, i know i would be defected if inspected...

[mryangtastic]

in regards to the current car's situation - does it concern you that your product was installed so badly? they look like great parts, but a good part is only as good as it's installation!

I'd like to know too. [emoji1]
How am I able to revert it back to how they came out of the box?

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