bouncy ride & harsh on small bumps...

[rzorrilla2348]

I've been tweaking my ride for years...but the ride is still a bit harsh on small bumps (like I feel every crack in the pavement)... like the coils are too hard so I moved from 31s to 35" BF AT K2s ... and it helped somewhat but now a bit bouncing at 30psi. Ultimately, I suspect it's my 10+yr coils...(I think they're variable rate Duffs but not sure)

Here's where I'm at... 76' 351w. front 3.5" coils with drop arm. PS. no body lift. Hellwig front sway bar. 5125 Bilstein singles. New rear Tom's springs ~2-3" (as I took some leafs out to level the back/front). 6degree shim for driveline angle adjustment.

I just ordered the Hellwig rear sway bar in the hopes it'll help...

 

[mrdrnac]

You said 30psi, is that your tire pressures? If so, try reducing your tire pressures, for example, I run 37" tires but I also run 24psi in the front and 20 psi in the rear. Lower pressure will help the ride.

 

[DirtDonk]

Normally the variable rate coils ride very well initially, but if yours are sagged down a bit due to both the extra few pounds of the 351 and the extra years on the coils, you might be into the stiffer coils to start with. And generally speaking too (though I can't speak for old Duff's), the secondary coils are stiffer than stock even.
Your shocks should be decent and not part of the problem, unless you actually have a bum shock. But luckily so far I have not heard of anyone having a bum Bilstein out of the box.

The tires are a key though. Since you said it improved when you went to the 35's with the taller sidewall, I would definitely do what mrdrnac suggested and take them down even more. You could start with 2psi at each step, just to see what you like.
But keep an eye on the tread wear to make sure you're not going too low for the particular tire/wheel combination.
Same for the rear, which are easier to keep an eye on anyway. You can use chalk across the tread to see where it wears out, but in general if you're driving it regularly just keep an eye on the dirt patterns. If they are showing you that you're riding on the center of the tire, let more out until you see wear patterns all the way out to the edges of the tread. Just don't let it wear down over the corners and down to the side lugs.

Good luck.

Paul

 

[rzorrilla2348]

Thanks for the feedback. I'm going to play around with tire pressure for now while monitoring tread...as there's no cost to it. Curious, what's the average lifespan for coils? How different is variable-rate compare what I'm seeing now, "progressive"?

 

[DirtDonk]

Lifespan of coils? Pretty much a variable still, even with all the knowledge of the last 200 years or so.
A typical coil should last at least 5 years before you see any sag, but most will last 15 years or more. I've had them sag down a little bit in a couple of years, then no more for the next twenty. And I've had them last at full height for 30 years and more.
It just depends... But on what, I don't know. Mostly the springs themselves, because I've had hard-used ones last longer than those that had easy lives. So it's not always how badly they're treated.
However, loading them down and keeping them that way is generally accepted to shorten their life. Or more accurately, their "acceptable ride height" since they may still live long and prosper even if they sag.
But a broken spring still happens too. Just pretty rare with our rigs I think. I've only seen a few over the decades. Many more in passenger cars, but that might be due to them being softer and cycling through more motion, more often than a stiffer truck spring? No idea, just guessing.

I would imagine variable rates (same thing as progressive) should not last as long because the primary windings are softer and can compress easily and springs can take a set. But my longest lasting set so far (on a Bronco) have been variables.

I think most are calling the progressive nowadays, but I think that's misleading and in fact, kind of wrong even. To my mind every spring is progressive, because the farther you compress it the more it resists.
Whereas a "variable" denotes that it has at least two distinctly different spring rates built in. Of course, even that term could be mis-interpreted to mean something else I suppose. But that's what I first heard them called long ago and that's what stuck with me.

Paul

 

[broncobilly72]

Hey Paul, when are you going to sit down and write your EARLY BRONCO repair book...I'm not kidding....too much knowledge going to waste!

 

[DirtDonk]

Hey, I thought that's what I was doing! Haha!
Really though, I'd have to actually verify the junk I spew out before putting it in real print. And where's the fun in that?

But thanks! Appreciate it. Publish, or perish as my dear mom always says...%)

Paul

 

[jim3326]

In my mind, with all it's missing cells, a variable would be either varying coil diameter or thickness. Progressive would be coils progressively closer together but with a constant diameter and thickness. Same theory would apply to leaf springs, just in a straight line.;D

 

[ZOSO]

Im gonna jump out and say the biggest and best thing you can do for ride quality is shocks. Most any modern spring (last 20-25years) are gonna be good for ride. What makes a huge difference is shock valving. I don't get why everyone jumps to the Bilstein bolt on shocks. Those are stiff valved. Im running Bilstein 7100's in the front with a custom valve pack and the ride improvement is well worth the investment.(I understand not everyone wants to spend $200-$250 a shock) If you were to ride in a bronco with shocks that were properly valved and not something off the shelf you'd make the change also.

But start with tire pressure's for sure. I run my 35's at 22-24psi for street use. After trying that you may even mess around with removing the sway bar. Those do affect ride quality also.

 

[rzorrilla2348]

update: I just finished my test drive after installing my Hellwig rear sway bar. It really helps...pleasantly surprised! It seems to me that having both front and rear sway tames the twist so much... yes, with the turns/cornering but on bumps too. IMHO, it stabilizes the suspension by keeping the frame from twisting on the bumps... and so isolating the suspension to deal mostly with the up/down motion. It absorbs the bumps even more and interesting as I could feel the suspension engage now.

Additionally, I lowered to 26psi on the 35"s..and yes, reducing the bounciness. Thanks to everyone for your feedback! Wow... I am even happier with my setup. Maybe in the fall, I'll pick up those WH progressive coils...

https://photos.app.goo.gl/VT7CuSsq9qrVK2AB8

https://photos.app.goo.gl/SwG4pjaTjrcN39Yb8

 

[bronconut73]

Before the new coils look into Duff's new Eibach shocks.

Duff had these monotube shocks valved and pressurized in a manner that would complement most eb suspension.
They could be your missing link.

Keep playing with tire pressure as it makes a very noticeable difference and the bonus is that you will have even tire wear across the tread instead of just in the center.

 

[Mikesimp70]

Mine was harsh after I got it all together. I have front and rear Helwig also. Toms 2.5” with Billsteins. 31s x 10.5s. Really helped when I flipped my leaf springs so they weren’t in backwards. Its worth a look.

 

[blubuckaroo]

I may be in the same condition. My variable rate coils are against each other at the top.
On a positive note, new coils are cheap and I work cheap.
Sorry the photo is sideways, but you can see the whole top part of the spring is useless. 10 year old, just like the shocks. Time for a replacement.

 

[RODRIG3911]

Earlier in the year I was going through the same thing. Better shocks and Deaver coils made mine ride awesome! I LOVE those Deaver coils! They are 190 pound linear rate. That combined with custom tuned ADS 2.5" smoothies made all the difference.
I replaced the progressive Duff ones that where pretty good, but not great at washboard roads at high speeds or pot holes... I actually would have kept the Duffs if it wasn't for pulling the coil out of the lower cup articulating while 4 wheeling. My set didn't wrap far enough into the cup.. (Not bashing Duffs at all. I got there long arms and ms2020 shocks in the rear. Deavers are better coils for me in my rocky desert environment)

 

[jim3326]

I may be in the same condition. My variable rate coils are against each other at the top.
On a positive note, new coils are cheap and I work cheap.
Sorry the photo is sideways, but you can see the whole top part of the spring is useless. 10 year old, just like the shocks. Time for a replacement.

That looks normal to me for a loaded spring. They're close but not touching from what I can tell. My WH progressives look almost identical.

 

[66horse]

Im gonna jump out and say the biggest and best thing you can do for ride quality is shocks. Most any modern spring (last 20-25years) are gonna be good for ride. What makes a huge difference is shock valving. I don't get why everyone jumps to the Bilstein bolt on shocks. Those are stiff valved. Im running Bilstein 7100's in the front with a custom valve pack and the ride improvement is well worth the investment.(I understand not everyone wants to spend $200-$250 a shock) If you were to ride in a bronco with shocks that were properly valved and not something off the shelf you'd make the change also.

But start with tire pressure's for sure. I run my 35's at 22-24psi for street use. After trying that you may even mess around with removing the sway bar. Those do affect ride quality also.

Zoso, Can share what custom valve pack you are running?

Thanks,
Steve

 

[ZOSO]

Zoso, Can share what custom valve pack you are running?

Thanks,
Steve

These are numbers for Bilstein 7100's. A bit different than what is offered or recommended but that because its a digressive valve not linear that most offer. This is a good starting point and can be adjusted up or down for your needs.

345-135D for the front and 275-110D for the rear

 

[66horse]

These are numbers for Bilstein 7100's. A bit different than what is offered or recommended but that because its a digressive valve not linear that most offer. This is a good starting point and can be adjusted up or down for your needs.

345-135D for the front and 275-110D for the rear

Cool. Thanks. I have a set of 7100s I am going to put in the front of one of the broncos. Ill probably give this a try.

Cheers,
Steve

 

[70 sport WA]

Just one experience here....no lift, brand new 32" Coopers and I was getting that harsh ride. Stock coils (probably original from 1970). I changed out the shocks, which were dead, with basic $20 shocks from Rock Auto. When I took them off, they were ALL dead.

Now, I go over speed bumps and the ride is better than in my new car. There's a stretch of road that is "wavy" for about 150 yards and cars bounce up and down going 40mph. My Bronco now takes it without the same bouncing.