Front and Rear spring ratings

[stephen low]

Guys

I've done some searching through the forum for any identified spring ratings in use on your cars.

I did this as I was with my suspension bloke today for him to measure up for my shocks and he asked about spring ratings.

I've no idea what ratings the springs are in my car, these were part of the original package, but I quoted ratings Marty had indicated to me as front 500 - 550 and rear as 450 - 500lbs.

My bloke thought the rears at least were quite a heavy rate.

So to save a lot more forum scrolling time, I'd love to hear what front and rear spring rates you are all running.

Realise all the cars are different but then too they are very similiar and I suspect a modest sample of rates is going to hone in generally on a range at least that I can consider.

My suspension bloke has a link to at least one knowledgeable bod in the cobra game and will be asking him his opinion.

Look forward to some feedback and many thanks in advance.

Cheers

Steve

[cycleguy55]

465 lbs/in QA1 coilovers in front (Mustang II front end). Rear coil springs (not coilovers) are 300 lbs/in, I believe. Keep in mind this is on a ~3,000 lb West Coast Cobra with a heavy 460 CID engine and a longer wheelbase.

[DesertMK4]

FFR Mk4 front 500, rears 350. The front carries the engine, radiator, etc. I changed out to 450 front and 300 rear. Removes much of the harshness and initial shock of even small bumps. Ford small block. I have the stock FFR springs for sale. New are about $65 each. Used about 2000 miles. $45 each plus shipping. PM me if interested.

[EM-0785]

Originally Posted by stephen low

Guys

I've done some searching through the forum for any identified spring ratings in use on your cars.

I did this as I was with my suspension bloke today for him to measure up for my shocks and he asked about spring ratings.

I've no idea what ratings the springs are in my car, these were part of the original package, but I quoted ratings Marty had indicated to me as front 500 - 550 and rear as 450 - 500lbs.

My bloke thought the rears at least were quite a heavy rate.

So to save a lot more forum scrolling time, I'd love to hear what front and rear spring rates you are all running.

Realise all the cars are different but then too they are very similiar and I suspect a modest sample of rates is going to hone in generally on a range at least that I can consider.

My suspension bloke has a link to at least one knowledgeable bod in the cobra game and will be asking him his opinion.

Look forward to some feedback and many thanks in advance.

Cheers

Steve

Steve,

While I first thought I don't know for your setup, I realize per your comment that I bolded above, you're looking for samplings of other's members' spring rates, for perspective. Here's mine...

I recently upgraded to QA1's all around. I have a heavier Everett-Morrison with iron headed 460 and jag rear at about 2,900 lbs. The coilover springs I went with are 2 ea. @ 500 lb front and 4 ea. at 250 lb rear.

QA1 and others offer sizing guidance charts and tech support to discuss standards, nuances, etc. Each angle degree, length and many other forces/factors apply and there are dizzying calculations methods online, etc.. I too took in lots on info/research and zeroed in on 'likely' rates.

I also relied on experience/advice from Vintage Wheels and Shell Valley who helped me with certain of my suspension upgrades and determinations in the process. I utilized QA1 tech support often to vet all of my questions and concerns and double check to verify my understanding and how I was asking it.

All that,resulted in the rates I mentioned above for my application and usage needs. Basically, comfortable street cruising with some corner carving and some quality performance oriented capabilities in general. I went with the double adjustable shocks to ensure flexibility if/as needed, particularly as I was looking to overcome some suspension issues, didn't want to limit my options for tuning. I figured, the majority of cost and time is going in as a core project regardless, don't want to end up preferring those later then and re-doing. 'Very' happy with so far.

By the way, when I compressed springs, I was uncomfortable upon using the auto store rental compressors. Ended up buying a plate style compressor with much more apparent control/leverage. Then bound the springs using 1/2" wide 250 lb test plastic zip ties that I tightened with large pliers. (The 250 lb zip tie is a manly helper.) Used enough ties that it was certainly overkill, but I felt better safe than sorry at that.

Was able to dial in the desired compressed heights easily for rear install for example, snip, snip...done. I chose to do with remaining suspension in place.
That said, don't take my word on spring compression it's risky obviously, to be done with/by experience and knowing the risks!

Brent

[stephen low]

Thanks Guys for the input.

Trolled a fair part of the Aussie forum too and have about 10 - 11 rates recorded.

Interesting medians as Front 360 lbs and Rear 293lbs.

Will take input from my shock supplier who has supplied a local eminent builder of cobra's here as well for advice.

I too am going double adjustable shockers but after much deliberation decided it is probably a once off purchase so don't spare the lolly and that I buy items that can be rebuilt and revalved.

Finally had three brands in my sights as Penske, Bilstein and Koni and I am committing to the Koni's. My suspension provider has already taken a raft of measurements and the plan is for a compliant car with well sorted handling for the street and the capability to be tweaked for the very occasional track use.

I know it will be chalk and cheese in handling compared to the current set up and along with new Vintage rims to ditch the square wheels I am currently running she should be a totally different handling beast.

Thanks again for the input.

[cycleguy55]

Originally Posted by stephen low

Thanks Guys for the input.

Trolled a fair part of the Aussie forum too and have about 10 - 11 rates recorded.

Interesting medians as Front 360 lbs and Rear 293lbs.

Will take input from my shock supplier who has supplied a local eminent builder of cobra's here as well for advice.

I too am going double adjustable shockers but after much deliberation decided it is probably a once off purchase so don't spare the lolly and that I buy items that can be rebuilt and revalved.

Finally had three brands in my sights as Penske, Bilstein and Koni and I am committing to the Koni's. My suspension provider has already taken a raft of measurements and the plan is for a compliant car with well sorted handling for the street and the capability to be tweaked for the very occasional track use.

I know it will be chalk and cheese in handling compared to the current set up and along with new Vintage rims to ditch the square wheels I am currently running she should be a totally different handling beast.

Thanks again for the input.

I trust you're planning to have the setup properly corner-weighted.

[1985 CCX]

10 leafs in front 8 in rear

[stephen low]

Ah 1985 CCX you wag......bastard - lol

But then you wanted an "old" car eh?

[sambo]

Hey Slowy. I originally had 250lb on the rear and 400lb on the front. Much better at the rear now with 300lb and I'm about to drop the front to 350lb. Just pick a ballpark and it's relatively cheap to move up or down to get it right - compared to the price of fuel at the moment!

[Allanfrost]

Hi all, I am brand new to the forum as well as Fords.I have tons of questions.My project is second hand from "Classic Motor Carriages" Using a 460 very concerned about the weight factor ...on the Mustang II front end.Can anybody tell me what coil springs I should be using...also location of motor mounts. I'm going to need lots of help.....Thanks in advance.
Allanfrost

[cycleguy55]

Originally Posted by Allanfrost

Hi all, I am brand new to the forum as well as Fords.I have tons of questions.My project is second hand from "Classic Motor Carriages" Using a 460 very concerned about the weight factor ...on the Mustang II front end.Can anybody tell me what coil springs I should be using...also location of motor mounts. I'm going to need lots of help.....Thanks in advance.
Allanfrost

I'm running 465 lbs/in QA1 coilovers in front (Mustang II front end). Rear coil springs (not coilovers) are 300 lbs/in (I believe) with QA1 adjustable shocks. The rear springs are vertical, while the fronts are on an angle - that affects spring rate. Keep in mind this is on a ~3,000 lb West Coast Cobra with an iron-headed 460 CID engine and a 96" wheelbase.

As to motor mount location I'll only say our cars are too different, but I'd say shove it as far back as you reasonably can.

[stephen low]

So test drove my car last night with the new suspension on board,

What a different car it is, reactive and lively, and no squeaks I now realize were part of the old gear.

Spring rates have ended up at 500 front and 400 rear, and the car feels right.

A few pics from my short visit yesterday.

Front

[IMG] [/IMG]

Rear

[IMG][/IMG]

Some ride height and bump/rebound settings readjustment and installation of the front sway bar and the car should be able to be collected today (Thursday).

Next is Marty's for the rear end swap over and re-engineer to suit the new Vintage rims plus a diff fix c/- Big Block Billy and that should be the suspension all done.

It'll be a new car handling wise.

Enjoy

[Rob. Smith]

Well ..I just spent 1/2 an hour trying to download pics of the correct mathematics for you to calculate the correct spring rates. My engineer gave me the formulas . he also sent them to East Coast Suspensions and told us both to work the math. A week later we compared 3 separate results and they all came in the same . Alas this site won't let me down load pictures of the calculations. I apologise for not being able to help you. I haven't driven my car in anger yet but the very few times I've had it on the road . It handles well and rough roads are soaked up nicely. It might prove to be a bit soft but that can be sorted with sway bar adjustment. My car is an RMC .. heavy (about 1200 + kg) but stiff. Good luck with your works. The suspension companies' name that I dealt with is .. East Coast Suspension
sales@eastcoastsuspensions.com.au www.eastcoastsuspensions.com.au

[stephen low]

Thanks Rob

Hopefully all the money I've spent included this young bloke's brains trust to get the car right and balanced. It certainly feels that way as I have driven over quite a variety of surfaces testing it and had no ride complaints.

Only disappointment from later slow speed driving on a variety of uneven surfaces is that the car has redeveloped some suspension movement noises and creaks.

I have to assume it is all the arm bushings and rubbers and not the new gear.

I know when I reassembled everything it was all new Jag rubber bushings etc.

Are there any cures for jag set ups in terms of suspension noise reduction?