What is your opinion progressive springs?

Rebellion · Feb 3, 2017

SteedaTech said:
First inch of travel from curb if so,then it is progressive. Most progressive springs go linear after a inch of travel from curb.

Dual rate springs remains the same linear rate from curb to jounce or full compression. Dual rate springs have decreased rate from extension past curb to induce less roll.

I will have some of the best vehicle dynamics spring engineers to explain some of our test data and give some great info for everyone. We work with several OE spring engineers on a daily basis.

It should be one inch from free length (where the inflexion of the graph happens), otherwise the graph wouldn't start from zero (impossible at curb height).

Curb height should be a compression of about inch and half or so, well within the linear zone of the dual rate. Therefore, for real life analysis purposes, the spring is linear.

BmacIL · Feb 3, 2017

SteedaTech said:
First inch of travel from curb if so,then it is progressive. Most progressive springs go linear after a inch of travel from curb.

Dual rate springs remains the same linear rate from curb to jounce or full compression. Dual rate springs have decreased rate from extension past curb to induce less roll.

I will have some of the best vehicle dynamics spring engineers to explain some of our test data and give some great info for everyone. We work with several OE spring engineers on a daily basis.

Nearly 100% sure that test data is starting from free, not curb compression. The free height of the 350R front spring is 10", and it's tested to 5" compression, so it would be very close to/at solid height, as it wouldn't compress 5" from curb height. The rear spring has more coils and higher pitch, so it would have less compression before solid height is reached. All this being true would make them dual rate.

If you guys have additional test data on the 350/350R springs it'd be great to see.

SteedaTech · Feb 3, 2017

BmacIL said:
Nearly 100% sure that test data is starting from free, not curb compression. The free height of the 350R front spring is 10", and it's tested to 5" compression, so it would be very close to/at solid height, as it wouldn't compress 5" from curb height. The rear spring has more coils and higher pitch, so it would have less compression before solid height is reached. All this being true would make them dual rate.

If you guys have additional test data on the 350/350R springs it'd be great to see.

Will do, we had two independent OE suppliers do testing on the 350 and 350R.

We bench marked the 350R spring to make our new comp spring and listen to advanced spring engineers plus, pro road racers around the country.

We will provide the data early next week. Let's keep this educational for everyone.

BMR Tech · Feb 3, 2017

Free height, installed height and rates tested from installed height to 2.5" compression on GT350 and GT350R coil springs.

Let's get that data presented and discuss.

:thumbsup:

BMR Tech · Feb 3, 2017

[MENTION=25806]SteedaTech[/MENTION] do you guys not test springs in house?

SteedaTech · Feb 4, 2017

BMR Tech said:
[MENTION=25806]SteedaTech[/MENTION] do you guys not test springs in house?

We do test springs in house, we have been for the past 25 years.

We have been working with the same two Motorsport spring engineers for over 20 years. Which have engineered springs that have broke track records across the country. Tom Ellis last month for example broke the track record in A/S at the SCCA Majors at Homestead and Sebring.

Looking forward to constructive and good information we can provide to the performance enthusiast.

Thanks Mike D

TrackpackGT · Feb 4, 2017

I loved my Hypercoils on my 99 Trans Am. I would imagine they supply someone with springs, fantastic products.

BMR Tech · Feb 4, 2017

That's awesome Mike. I look forward to your information that you share. I'll likely throw some info in as well and we can discuss the details.

:headbang:

Norm Peterson · Feb 4, 2017

valentinoamoro said:
Wow. Incredibly useful and insightful answer. Thanks. I learnt something new. Wondered why folks using lower stiffer springs on PP shocks were claiming better ride.

Probably because the percentage of critical damping moved downward. Away from best performance toward best ride (which IIRC is looking at vertical accelerations rather than any tendency for "bounce").

It's basically what you're intentionally doing with adjustable shocks when you dial them back down after a track day for the ride home. Or do again when your passenger prefers a softer ride than you would by yourself, or when the road conditions are unusually poor.

Norm

Norm Peterson · Feb 4, 2017

Separately, I wonder how many of the springs that are advertised as being "progressive" are really dual-rate (and how many of their customers know this and what they really have). Dual-rate is not the same thing as progressive.

Norm

Norm Peterson · Feb 4, 2017

Bluemustang said:
It's in the title. I want to pose the question to gain more information and opinions. Most folks here seem to dislike progressive springs and favor linear ones. But other folks have said that there's nothing wrong with them and can actually handle better if setup right.

What's your view on progressives and why?

Getting the damping set will be trickier, and it may not even be possible to optimize the damping for both rates at the same setting(s). Not that the vast majority of street driving demands damping optimized for performance.

Norm

SteedaTech · Feb 6, 2017

View attachment 113199

SteedaTech said:
Your information is incorrect, the GT 350R has progressive springs in the rear and linear in the front.

I will provide great technical info from our engineers next week regarding this post.

Here are the numbers. No twisted propaganda please. We tested every 1/4 inch where others tested every 1/2 inch.

BmacIL · Feb 6, 2017

SteedaTech said:
Here are the numbers. No twisted propaganda please. We tested every 1/4 inch where others tested every 1/2 inch.

Thank you for the data! Can you identify at which compressed height corresponds to nominal ride height? Do you also have this for the GT350R springs (FR3Z-5310-M and FR3Z-5560-T or X)?

BMR Tech · Feb 6, 2017

SteedaTech said:
Here are the numbers. No twisted propaganda please. We tested every 1/4 inch where others tested every 1/2 inch.

[MENTION=25806]SteedaTech[/MENTION]

I am having a hard time following your data provided.

You are claiming 265 as the rate when compressing the Front spring from 9.108" to 8.108" - but your load goes from 413lbs to 624lbs.

Correct me if I am wrong, but isn't that 211lbs required to compress the spring 1"?

Safe to say your spreadsheet is adding (5) difference columns instead of (4)?

May wanna fix that up, so not to mislead the readers. Just looking out :thumbsup:

SteedaTech · Feb 6, 2017

BMR Tech said:
@SteedaTech

I am having a hard time following your data provided.

You are claiming 265 as the rate when compressing the Front spring from 9.108" to 8.108" - but your load goes from 413lbs to 624lbs.

Correct me if I am wrong, but isn't that 211lbs required to compress the spring 1"?

Safe to say your spreadsheet is adding (5) difference columns instead of (4)?

May wanna fix that up, so not to mislead the readers. Just looking out

I would contact a spring engineer so you can understand our table.

Or, you can call our engineering dept. at 1800 950 0774 to discuss, they will be able to explain the table in greater depth.

On another note, provide your data for the rear GT350 .

What is your opinion progressive springs?

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