Smoother Highway Ride for Coilover Conversion

[CraigS]

I find this thread curious. A given suspension style can't give a decent ride? What? First realize that one difference between an IRS and a solid axle is that the IRS will usually have some leverage built in so the spring or shock rate is not the effective wheel rate. The wheel rate will usually be much softer than the spring rate. The solid axle will have the two rates nearly identical. I mention this because (assuming the lengths would fit) a given coil over unit that rides great in an IRS car will be very much stiffer if moved to a solid axle car. Regarding ride comfort only, as long as both systems will allow 5-6 inches of wheel travel (without binding control arms or unwanted contact to frame or body) both can be made to ride well. The IRS will have the advantage when on rough pavement because of much less unsprung weight but, other than that ride can be nearly the same as IRS. There are a lot of other advantages to IRS regarding geometry but to say a solid axle car can not be made to ride reasonably is crazy.

[dhutton]

Originally Posted by CraigS

I find this thread curious. A given suspension style can't give a decent ride? What? First realize that one difference between an IRS and a solid axle is that the IRS will usually have some leverage built in so the spring or shock rate is not the effective wheel rate. The wheel rate will usually be much softer than the spring rate. The solid axle will have the two rates nearly identical. I mention this because (assuming the lengths would fit) a given coil over unit that rides great in an IRS car will be very much stiffer if moved to a solid axle car. Regarding ride comfort only, as long as both systems will allow 5-6 inches of wheel travel (without binding control arms or unwanted contact to frame or body) both can be made to ride well. The IRS will have the advantage when on rough pavement because of much less unsprung weight but, other than that ride can be nearly the same as IRS. There are a lot of other advantages to IRS regarding geometry but to say a solid axle car can not be made to ride reasonably is crazy.

I can only reiterate my experience building two 69 Camaros. The iRS car had a much better ride than the Ridetech four bar. Night and day. Even had Bret the owner of Ridetech ride in the car and suggest changes. No real difference. Maybe the solid axle cars CAN ride as well as an IRS but I’ve not seen any commercially available suspension kits that do….

I see that Roadster Shop is now offering a chassis optimized for ride called the Ride Line. I was contemplating buying one for my 59 Chevy pickup to compare to my C5 IRS equipped 56 Chevy pickup. Unfortunately they are now quoting 10 month delivery times which is a little bit crazy imho….

Don

[CraigS]

Don think back to a bone stock 69 Camaro. Did it ride OK? So what has changed? To me overall suspension design can get into a lot of stuff w/ roll centers, instant centers, etc. But ride is much reduced from overall design. You need 5-6 inches of wheel travel w/o anything hitting anything else, no control arm bushings binding, no geometric binding (an old Fox Mustang rear suspension would not roll if all bushings were replaced w/ spherical bearings), and reasonable shock and spring rates. The OP says his shocks are in the middle of their travel so that is good. I'd next disconnect, or remove if necessary, the coilovers to see if the suspension will move up and down w/o them. Next I think he also said the shocks are on #6 adjustment. Why? I don't know the specifics of those shocks but I have never seen any that #6 is the softest setting. Usually 0 or 1 is softest so that needs to be tried to see how it affects ride. And I may have missed it, but I haven't seen a spring rate # yet so we have no idea what he has. Based on your experience one other possibility is the shocks are completely wrong for the car. An adjustable shock has a range of stiffnesses available. The softest setting on these shocks could possibly be too stiff for this application. I once had the compression damping made softer in a pair of QA1 DA coilovers because it was too stiff for a good ride in a cobra replica. I figured that QA1 probably valved them more for something like a Camaro which would be 6-700# heavier.

[dhutton]

Originally Posted by CraigS

Don think back to a bone stock 69 Camaro. Did it ride OK? So what has changed? To me overall suspension design can get into a lot of stuff w/ roll centers, instant centers, etc. But ride is much reduced from overall design. You need 5-6 inches of wheel travel w/o anything hitting anything else, no control arm bushings binding, no geometric binding (an old Fox Mustang rear suspension would not roll if all bushings were replaced w/ spherical bearings), and reasonable shock and spring rates. The OP says his shocks are in the middle of their travel so that is good. I'd next disconnect, or remove if necessary, the coilovers to see if the suspension will move up and down w/o them. Next I think he also said the shocks are on #6 adjustment. Why? I don't know the specifics of those shocks but I have never seen any that #6 is the softest setting. Usually 0 or 1 is softest so that needs to be tried to see how it affects ride. And I may have missed it, but I haven't seen a spring rate # yet so we have no idea what he has. Based on your experience one other possibility is the shocks are completely wrong for the car. An adjustable shock has a range of stiffnesses available. The softest setting on these shocks could possibly be too stiff for this application. I once had the compression damping made softer in a pair of QA1 DA coilovers because it was too stiff for a good ride in a cobra replica. I figured that QA1 probably valved them more for something like a Camaro which would be 6-700# heavier.

Craig, you obviously know more than I do about suspension. I can only recount my experience and reiterate that I had the president of Ridetech drive my car.

One comment though. Ridetech monotube shocks are not compression adjustable. Only rebound is adjustable because that is generally a limitation of monotube shocks, they can’t be made double adjustable without remote reservoirs. So with a Ridetech setup only rebound is adjustable. Brett from Ridetech told me that compression adjustment doesn’t do anything anyway because the spring rates are so high. The rebound adjustment is essentially used to dampen the rebound due to all the stored energy in those high preload, high spring rate springs imho. If the damping is too low I think it can lead to the loud bang that happens when driving over a drop in the road surface at speed. Note that the Ridetech ride is fine on smooth roads. It’s these discontinuities in the pavement that generate the harshness.

The other thing I will reiterate is take a look at the Roadster Shop Ride Line chassis. They have incorporated a lot of the improvements that I have been whining about for years. So apparently I’m not the only one thinking this way.

Don

[camcojb]

Originally Posted by dhutton

The other thing I will reiterate is take a look at the Roadster Shop Ride Line chassis. They have incorporated a lot of the improvements that I have been whining about for years. So apparently I’m not the only one thinking this way.

Don

That's why I went with the Roadster Shop ride chassis they're now doing. They have a specific shock/spring package developed specifically for that. Ride quality is the optimum goal, but I'm not at the point to be able to give an opinion on how it works yet.

[dhutton]

Originally Posted by camcojb

That's why I went with the Roadster Shop ride chassis they're now doing. They have a specific shock/spring package developed specifically for that. Ride quality is the optimum goal, but I'm not at the point to be able to give an opinion on how it works yet.

Their Ride Line chassis takes it to another level. Very interesting design but they are pretty proud of it…. I was considering one but 10 month leadtime with a non refundable $11k deposit was a bit much for me.

Don

[CraigS]

Well dang, this is wrong for sure.
"Brett from Ridetech told me that compression adjustment doesn’t do anything anyway because the spring rates are so high."
What the heck did they design/tune their stuff for? Apparently not for the street.

[Vegas69]

What about a dual rate spring? You'd give up some performance, but perhaps it would soften up the ride under normal conditions.

I had a G Bar in my Camaro which is basically the same thing I believe. I went to a dual adjustable shock and I personally think compression adjustment benefited the ride. There is also the option to build custom axle brackets to allow a longer shock and spring. I lowered my shock mount about .5" to get my shock in mid stroke on my G Bar. I found that I was bottoming out my shock under heavy load prior to the modification. I ended up being pretty satisfied with the G Bar after modifying the shock mount and going to dual adjustable shocks. In stock form, it's not ideal for a decent ride height. I mocked up my rear end without springs at my desired ride height and had the brackets made. It's a pretty simple job. I don't know if it will fix your issue, but I don't recall my car riding that bad.

[randy]

I didn’t realize the ride quality difference in my ridetech coilovers till I switched my rears to jri and had Jj valve them at ultimate performance. I wish I would have went with the jri from the beginning

[NOVA]

Originally Posted by randy

I didn’t realize the ride quality difference in my ridetech coilovers till I switched my rears to jri and had Jj valve them at ultimate performance. I wish I would have went with the jri from the beginning

This is Interesting ..... glad it made a noticeable difference in your case, how did it change, do you feel it took the harshness out of the ride or ?