Too soft springs?
Does the springs on my MII suspension looks too soft? To make the lower A-arms parallell with the ground I had to compress them a lot. Have a look at he photos (not very good, i know. It's not much room around the car in my garage)
The car has been a rolling chassis for 5-6 years, but isn't driven yet. Still the springs looks and feels very soft to me. What do you think? Should I switch to stiffer ones? And if so, what rate do you recommend?
The invoice from Fat Man only states "Coilover shocks-pair assembled with proper rate springs." But I guess they will tell what spring rate they use if I ask them.
the car is a 34 Ford Roadster high boy, Chevy 1st gen small block motor, aluminum radiator, aluminum water pump, aluminum intake, no AC no power steering, steel hood and steel hood sides.
The answer to your question will come if the springs can be compressed to the point where they bind - to the point where the coils are completely compressed with no space between them. If this occurs, you'll need different springs with a higher spring rate - fewer coils and more space between the coils.
That said, I don't think you'll have a problem. Have a look at the coils on my Dad's car. They are 400 pound rate springs. The number of coils and the space between them is similar to yours. I've never had a problem with the springs binding even though there's plenty of travel in the wheels.
What worries me is that I have compressed the springs quite a lot, if you look at the lower, threaded part of the shock. But despite this, the car has raised close to nothing.
There are many coil spring calculators on the internet - from very simple to 'why do I need that information'. For the most part, you need the wire diameter, free coils and height and the angle they are installed. As a general rule, the Speedway/AFCO suggested chart works just fine for street rods. I have a TCI chassis under my '31 - they supplied springs that could have held up my 3500 kg pickup truck and it rode like one!!
My car now has 325 pound capacity in the front and 200 in the rear and is probably similar in weight as yours.
Current adjustment, about one inch +/- of thread:
The AFCO Chart
Took off the springs tonight. It was written 325 on the end coild on them. They measured 9" unloaded.
With the suspension in correct position, they are app 7" but not stiff enough to hold the car. They compress further down to app 6" before they stop.
QA1 don't make 9" coilover springs at all, so I guess they have been 10" from the start, and have sagged 1" during the time the car has been a roller?
I contaced Speedway and Heidt's and asked what they recommend of Mustang II suspension on my car (Fat Man where I bought the kit from, won't tell. They suggested somewhere between 450 and 500 lbs...)
Speedway suggested 375 lbs.
Heidt's suggested 425 lbs.
In both requests I pointed out that it was a Mustang II suspension, Not a rear steer IFS, as those usually have slightly angled springs.
Maybe a pair of 10" 400 lbs springs?
My Maverick is pretty light and has an aluminum LS motor too. I'm running Aldan 450# coilovers and it rides perfect. The outfit that built my front clip tried to sell me 550's, but after explaining about the all alum. engine, they agreed on the 450's and it all worked out fine.
Thanks for your answers!:welcome:
An update: The coilovers are Pro Shock, not QA1, and Pro Schock makes 9" springs, so the springs have probably been 9" all the time.
I have decided to change into stiffer ones.
Should I buy Chrome or "near chrome" silver powdercoated springs?
I have polished stainless steel A-arms, so chrome will look best when new, but is chrome springs "show, not go"?
Which of them will look best after some years of use?
See post #4. Those are chrome AFCO's and have two full seasons on them and they look as good as the day I installed them. Be aware that all companies don't do as good a job on the plating as the first set that I bought (QA1) were @#$% and returned for credit. Too bad you aren't closer as I have my original too heavy for the car progressive rate take offs that might have worked with a bottom coil removed and ground smooth
The cars not on the road and you haven't driven it yet you are anxious to get the ride right. You need to drive it at a couple hundred mile to let the springs settle and to decide if you want stiffer or softer springs. I think you would be just making more work for yourself and spending money you may not have to.:welcome:
Have a look at the photos in the first post. The springs are compressed almost at coil bind level already. This just can't be a good ride.
And in addition to that, the springs are much softer than both Speedway Motors and Heidt's recommends.
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