Inside rear wheel unloading

[plohl]

I don't belive you

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[pepejesus]

How do tenders give you 50mm of droop over an uncaptive Spring?

They continue to push the wheel toward the road when your main spring is fully extended and cannot push any more.

Wouldn't the unsprung weight pull it down to max droop when the spring becomes uncaptive?

Nope, or at least not at the rate that you need to maintain an effective contact patch. There is no time to wait for gravity to overcome damping forces when you've hit a bump or a kerb at 120km/h. You need a spring pushing that down.

[project.r.racing]

How do tenders give you 50mm of droop over an uncaptive Spring?

They continue to push the wheel toward the road when your main spring is fully extended and cannot push any more.

No they don't.

Said helper spring in your example video - I could squeeze it to be fully compressed with my own hands. They could've have enough sprung power to push that much mass downwards. They are only there to support the weight of the main spring so it doesn't wobble around uncaptured.

[pepejesus]

No they don't.

Said helper spring in your example video - I could squeeze it to be fully compressed with my own hands. They could've have enough sprung power to push that much mass downwards. They are only there to support the weight of the main spring so it doesn't wobble around uncaptured.

You have very strong hands. They are 150lb springs, more than capable of extending the shock at the end of droop travel.

The fact that they support the main spring is a nice side effect and not what they are there for at all.

If you don't believe it coming from me then maybe you will from the guy who developed the coilovers: http://forum.miata.net/vb/showpost.php?p=4874846&postcount=21

Notably: "The Xida, being a long stroke damper, requires dual springs to make full use of the extra stroke available. A 2000 lb car with the motion ratio of just under 1.5:1 won't compress a short 700# spring far enough to allow meaningful droop travel with long stroke damper. To get the correct ride height, one must lower the preload collar until the springs have 25-60mm of free play. Without the secondary springs (helper), there is no spring stroke left to push the tire down to remain in contact with the road."

[manga_blue]

I run 150mm 10/7 Tein springs with 95mm Tein helpers on Tein HA coilovers, torsen and OEM sways. At only 0.34 Kg/mm the helpers are designed to stop the springs flapping about at full droop and nothing more. They certainly wouldn't give enough pressure to hold an inside rear to the track.

Helpers are purely designed to correct droop probems on coilovers that don't have pre-load adjustment, i.e. adjustable lower perch and fixed upper perch. I can't see them being any use on more modern coilovers.

The Fishhook at Wakefield Park is designed to test out rear wheel unloading: downhill hairpin, off-camber wih tightening radius. It's all in the technique. I can easily unload the inside rear there if I drive it badly - turn in under brakes, drop the weight onto the outside front and then quickly floor it. What I have to do is transition very slowly and very early from brake to power by heel-toeing during turn in. I need to be on full power well before the apex. That helps keep the nose up and the rears down and avoids leaving a wheel spinning freely.

[pepejesus]

At only 0.34 Kg/mm the helpers are designed to stop the springs flapping about at full droop and nothing more. They certainly wouldn't give enough pressure to hold an inside rear to the track.

Yours maybe, but not all helper/tender/secondary/whatever-we-want-to-call-them springs. It really depends on the rate of the spring and the stroke of the damper. Yours are a low rate, and perhaps your set up doesn't need any secondary spring except to locate the main spring, but there are plenty of other set ups out there that are not like yours.

Helpers are purely designed to correct droop probems on coilovers that don't have pre-load adjustment, i.e. adjustable lower perch and fixed upper perch. I can't see them being any use on more modern coilovers.

There are about 4 pages of this thread discussing why that is objectively and demonstrably wrong.

[Magpie]

I don't belive you

Sent from my SM-N9005 using Tapatalk

I believe me Here is some maths, not sure who it came from

[project.r.racing]

Helpers are purely designed to correct droop problems on coilovers that don't have pre-load adjustment, i.e. adjustable lower perch and fixed upper perch. I can't see them being any use on more modern coilovers.

There are about 4 pages of this thread discussing why that is objectively and demonstrably wrong.

Or the setup is wrong, causing 4 pages of discussion.

My personal opinion, and I posted it earlier. Is the preload is incorrect.

And I agree with manga_blue. After 15 years and 7 coilovers, some old school 90s single perch adjustment type and modern dual adjustment type. What he said is spot on.

[project.r.racing]

No they don't.

Said helper spring in your example video - I could squeeze it to be fully compressed with my own hands. They could've have enough sprung power to push that much mass downwards. They are only there to support the weight of the main spring so it doesn't wobble around uncaptured.

You have very strong hands. They are 150lb springs, more than capable of extending the shock at the end of droop travel.

The fact that they support the main spring is a nice side effect and not what they are there for at all.

If you don't believe it coming from me then maybe you will from the guy who developed the coilovers: http://forum.miata.net/vb/showpost.php?p=4874846&postcount=21

Notably: "The Xida, being a long stroke damper, requires dual springs to make full use of the extra stroke available. A 2000 lb car with the motion ratio of just under 1.5:1 won't compress a short 700# spring far enough to allow meaningful droop travel with long stroke damper. To get the correct ride height, one must lower the preload collar until the springs have 25-60mm of free play. Without the secondary springs (helper), there is no spring stroke left to push the tire down to remain in contact with the road."

Note the progressive rate mention?

That is not a helper spring. That is a tender spring. I didn't see a mention of 150lbs, but I got no reason to disbelieve you. That club coilover is using 2 springs instead of one varible rate spring. Much like a rally car or offroad truck.

So no a helper spring will not push a wheel down. But a tender (or secondary) spring in a varible rate suspension will.

[pepejesus]

Helpers are purely designed to correct droop problems on coilovers that don't have pre-load adjustment, i.e. adjustable lower perch and fixed upper perch. I can't see them being any use on more modern coilovers.

There are about 4 pages of this thread discussing why that is objectively and demonstrably wrong.

Or the setup is wrong, causing 4 pages of discussion.

My personal opinion, and I posted it earlier. Is the preload is incorrect.

And I agree with manga_blue. After 15 years and 7 coilovers, some old school 90s single perch adjustment type and modern dual adjustment type. What he said is spot on.

Not making any comments on what pre-load Magpie is running, I'm just addressing this point:

Helpers are purely designed to correct droop problems on coilovers that don't have pre-load adjustment, i.e. adjustable lower perch and fixed upper perch. I can't see them being any use on more modern coilovers.

This is not a matter of opinion, this is simply wrong and I can demonstrate why it is wrong, and have done about 4 times already on this thread.

In an MX5, with a long(ish) stroke damper, stiff springs, and a low ride height, you will not have maximum droop travel without a secondary spring/dual rate spring/tender/helper/I-don't-care-what-you-call-it. This is not an opinion, it is a fact.

If you still don't agree then you either have a very different idea of why droop travel is 'useful' on a coilover (modern or otherwise), or you simply don't understand why you won't have optimal droop travel in the situation described above.

If it's the former, then we're so far apart on what we want out of our suspension systems that there really isn't any point talking about it any more.

If it's the latter, tell me what you don't understand and I will try and explain it again. But please read my other posts first, as well as the links to the other threads that I've posted, as well as the video I posted, as well as the link to the page where the designer of coilovers that clearly demonstrate why you're wrong explains in detail why you're wrong, etc etc....

Actually, why don't i just post the relevant bit again so you don't have to click on anything: "The Xida, being a long stroke damper, requires dual springs to make full use of the extra stroke available. A 2000 lb car with the motion ratio of just under 1.5:1 won't compress a short 700# spring far enough to allow meaningful droop travel with long stroke damper. To get the correct ride height, one must lower the preload collar until the springs have 25-60mm of free play. Without the secondary springs (helper), there is no spring stroke left to push the tire down to remain in contact with the road."

Helpers are purely designed to correct droop problems on coilovers that don't have pre-load adjustment, i.e. adjustable lower perch and fixed upper perch. I can't see them being any use on more modern coilovers.

The Xida is a modern coilover, designed specifically for the MX5, with adjustable pre-load, and very useful secondary springs.

[pepejesus]

Note the progressive rate mention?

That is not a helper spring. That is a tender spring. I didn't see a mention of 150lbs, but I got no reason to disbelieve you. That club coilover is using 2 springs instead of one varible rate spring. Much like a rally car or offroad truck.

So no a helper spring will not push a wheel down. But a tender (or secondary) spring in a varible rate suspension will.

If you'd read the thread you'd know that every single point you've raised has been addressed and dealt with, including your semantics argument.

[Magpie]

pepejesus again thanks.

To put this into context for me.

The rears (BC ER's) have 70mm of damper travel, hence a 7kg/mm spring that is 160mm long is a good match and there is no uncaptive spring. However the rear is were the inner wheel is unloading in certain situations. Further the unloading is happening at steady state cornering. Therefore unless the torsen is swapped out for a clutch pack type diff the corner needs to be taken in such a way as to minimise the unloading. One solution is to take a different line.

The front BC's have 127mm of travel but only use a 20mm longer spring. Based on pepejesus's posts and links this would be what would be classed as a long stroke damper, at least when compared to the rears. Further, this is supported by what was found with the Xida's "To get the correct ride height, one must lower the preload collar until the springs have 25-60mm of free play". Surprise, surprise this is almost identical to my situation!

SO, the solution is to run progressive rate springs in a suitable length or ADD an assist spring that has a decent enough rate to push the tire into contact with the road if and when the situation happens.

The question is when does it happen and what would be the spring rate of the assist springs need to be. I'm not using the word 'helper' as it would be wrong!

But, at least for me, am I a consistent enough driver doing consistent times to be able to benefit from making the front springs captive. NO!, I have not experienced the problem yet or don't have sufficient experience to identify it. Accordingly don't worry about what I don't know.

This is an academic discussion without the maths. On the weekend I will do the maths (I still have Plohl's previously posted ones).

[project.r.racing]

I wonder why Japanese companies like Cusco, Tein etc have never used secondary springs on their MX5 suspension? They must have real egg on their Japanese faces since they have been proven wrong by videos and links to one single product available.

I hope magpie finds his own solution to his problem. I'm doubtful this thread can go much further. Hence the personal attack starting to come out. Goodluck.

[project.r.racing]

No they don't.

Said helper spring in your example video - I could squeeze it to be fully compressed with my own hands. They could've have enough sprung power to push that much mass downwards. They are only there to support the weight of the main spring so it doesn't wobble around uncaptured.

You have very strong hands. They are 150lb springs, more than capable of extending the shock at the end of droop travel.

MY apologies. I was unfamiliar with the product. So wasn't aware of it being a secondary spring. I just assumed it was a helper.

I thought you were referencing manga_blue's comments on helper springs.

[Magpie]

Horses for courses. Making something for the general market is always a compromise and will not work for 100% of the people.

No egg on faces required, it is a case of using something to its extremes. This also explains why custom suspension is very expensive as it is a very small market and very technical.

As has been said by others in this thread if the budget was unlimited then the solution would be different.

project.r.racing do you use off the shelf suspension with no modifications, that is order it, bolt it in place and forget about it?