Torsion bars for better handling; your experience?

-
Forgot to mention I'm running EBC Yellow pads on C-body 11,75" discs.
They dust a fair amount too.
Put them on my Dart just over 2 years ago, Upgraded from Hawks HPS pads.
They've worn down quite a bit though. Probably will need to replace them next year I suspect.

IMG_3864_zpsu0kjpjbe.jpg
 
I'm in the process of rebuilding my front end.
I have qa1 upper control arms, KYB gas shocks, q1a lower control arms.
Stock 73 K member
hellwig sway bar

manual steering
340 engine with 727 auto
Kmember is from a 73 dart, I am going to run 11.75 discs and the late 70s single piston caliper.
I still need to decide on a size for my torsion bars ???
 
and what to do with my steering box.................
I will probably send it to Firm Feel.
I'm leaning towards the 20-1 instead of my current 24-1
Any input ???
 
1.03's or 1.06's. Unless maybe you're planning on autoX or road courses, then bigger. The 1.03's from PST are less expensive and you can get a FABO discount if you call to order, they have a good wheel rate for the street. Toss the KYB's in the trash, they're terrible for large torsion bars. Bilstein rcd's or hotchkis fox's for shocks. I've heard the Viking adjustables work well too but I haven't run those myself.

20:1 would be a good compromise for the steering, and will make it easier to deal with running more positive caster. I run a 16:1 manual box and still manage to handle the 275/35/18's I run, I've run those with as much as +8* of caster (briefly). I ran +7* for a decent stretch although currently I'm running +6.25* for caster. I may go back up a little on the caster though, 6.5* or maybe just under 7. A little makes a big difference actually, the difference between +7* and 6.25 was pretty significant for steering effort. Still probably not something you'd want to parallel park everyday though.

I haven't posted my set-up on my Duster in this thread although I've posted it a bunch. 74 Duster (Demon tribute), 340, 4 speed, B body 8 3/4-

1.12" torsion bars from Firm Feel
SPC adjustable UCA's from Bergman Autocraft
QA1 tubular LCA's with custom gussets
Delrin LCA bushings (Bergman Autocraft)
Adjustable strut rods
Hellwig 1-1/8" tubular front sway bar
Hellwig 7/8" rear sway bar (e-body)
Hotchkis non-adjustable fox shocks
AFCO 120 lb/in rear springs
1/2" spring offset w/ spring sliders
16:1 flaming river manual steering box
275/35/18 tires on 18x9's up front
295/35/18's on 18x10's out back

I've also run the car with 1" Just Suspension torsion bars (too soft for me) and 11.75" disks. The 11.75" disks work great but I run Dr diff's 13" cobra style set up now with the 18" wheels. I had bilstein's on it as well for awhile with the 1.12" bars, they work well but the hotchkis shocks handle the 1.12's just a little bit better. It's a small difference but with the 1.12" bars the hotchkis shocks are slightly better. I still have bilsteins and 11.75" disks on my Challenger, it's a good set up but my Duster is set up a little more aggressively for handling. Still my daily driver though.
 
Last edited:
you guys are in a much more advanced league than me,but here's what i did and found.
My changes were .920 torsion bars, Bilstein shocks and expo 6 leaf rear springs with the
stock sway bar,disc brakes and 70 series tires...sm blk '69 Dart.
the car has a much more modern feel, is firmer and the ride is nice on good roads. The
problem is that most of our roads are not good and the ride is harsh and uncomfortable
because of them.I am going to do some more experimenting.My new vehicles including my truck,ride,handle
and stop on these same roads with exceptional comfort...i think i am just spoiled.
 
i've read stiffening the front or rear will cause understeer, also that the front suspension should be much stiffer than the rear and to be careful with rear sway bars...how do you decide which components to use when you start making these changes...especially shocks.
i feel i gained in some areas and lost at others?
 
ir3333 said:
you guys are in a much more advanced league than me,but here's what i did and found.
My changes were .920 torsion bars, Bilstein shocks and expo 6 leaf rear springs with the
stock sway bar,disc brakes and 70 series tires...sm blk '69 Dart.
the car has a much more modern feel, is firmer and the ride is nice on good roads. The
problem is that most of our roads are not good and the ride is harsh and uncomfortable
because of them.I am going to do some more experimenting.My new vehicles including my truck,ride,handle
and stop on these same roads with exceptional comfort...i think i am just spoiled.
Click to expand...

I found that even with 1.12" torsion bars and the hotchkis shocks that the ride quality of my Duster was about the same as my wife's 2013 Mustang with the factory premium suspension option. Now, she always had the thing is sport mode, so maybe that had something to do with it. When I was running 1" Just Suspension torsion bars in it I found the car to still be quite a bit softer than most modern vehicles, I think I still had the old blue gabriel shocks on it at that point though. I mean it handled better than stock, but it still had a lot of body roll with corners.

Suspension has to be matched, it's a system. If you run 70 series hockey puck tires, you don't have a ton of grip. That limits your handling, your braking, everything.

The other thing is ride height- If you only have .920" torsion bars, and you've lowered the car any from stock, you're probably still bottoming out the suspension onto the bump stops on rough roads. And that is going to give you a harsh ride, even with the factory progressive bump stops. I hear that a lot, people that increase the size of the bars slightly and complain of a harsh ride. Well, you have a higher wheel rate, but you're still bottoming out. The ride with the 1" bars on my duster was anything but harsh. It was still almost plush. But I hadn't done much if anything to the ride height at that point. The bars aren't stiff enough to make up for a big loss of suspension travel from lowering the car. You can get away with a little, but not much. A .92" torsion bar is only like a 150 lb/in wheel rate. That's not much more than most of the stock .87" V8 A/C bars, which are 120 lb/in. That's stock, and that's undersprung. Most 1" bars are around 200 lb/in, the 1.12" bars I run are 300 lb/in. And that's how I can lower my car, because my suspension is 250% stiffer than stock and uses a lot less suspension travel.

And, ride quality is subjective. What you expect from an old car and what you expect from your new car can change your mindset too. And what I think is "harsh and uncomfortable" may be totally different from what you think.

ir3333 said:
i've read stiffening the front or rear will cause understeer, also that the front suspension should be much stiffer than the rear and to be careful with rear sway bars...how do you decide which components to use when you start making these changes...especially shocks.
i feel i gained in some areas and lost at others?
Click to expand...

Again, everything has to be matched and it depends on your set up. If you run narrow, hard tires you can make the front too stiff and you'll get understeer pretty quickly. If you make the rear too stiff you'll get oversteer. And if you're running 70 series tires you don't have a ton of grip, so you don't want your suspension to be super stiff. The tires will just give up before the suspension starts to work.

The front suspension should be quite a bit stiffer than the rear, you just have to look at the weight balance of the car. These cars are nose heavy to begin with, so, the front suspension carries more load. The front suspension also deals with steering, so again, more load. And any time you brake, you shift even more load to the front.

So, it's all physics, and it's trial and error. I based a lot of my suspension choices on what guys were already running at autoX's and on the road courses, autoxcuda and gmachinedartgt (peter bergman) had a lot to do with what I chose for suspension. And I still missed a few times and have made changes. Even looking at what the aftermarket companies are offering helps. Hotchkis does a ton of research, and their cars handle really well. So, you can look at the wheel rates they run to help make decisions. But it also depends on your individual set up. The tire compounds and sizes you run make a big difference. In the back your power levels make a difference too. If you run a stagger in width from front to rear it makes a difference. My front suspension has a wheel rate of 300 lb/in just off my torsion bars, and I have a 1 1/8" sway bar on top of that. Meanwhile in the back I have 121 lb/in leaf springs, so I run a 7/8" sway bar. But I also have 295's back there, and they're hard to break loose. I know both Peter Bergman (gmachinedartGT) and hotchkis were selling springs that were 130 lb/in for A-bodies. But both Peter and Steve (autoxcuda) had remarked their cars were getting a little tail happy in certain situations with a rear bar, so I went with 120 lb/in springs. Both of those guys still use a rear sway bar though, just not on certain tracks.

Shocks have to be matched to the wheel rates, but better shocks have a wider range where they'll be good than cheap shocks. More valving and tuning. I was running Bilstein's on my Duster because that was one of the few shocks being made specifically for handling mopars, but I got a chance to buy a set of Hotchkis Fox non-adjustables second hand and mildly used so that was how I found out they worked a little better with my 1.12" bars than the Bilsteins did. That was just straight up trial and error. I ran KYB's on my Challenger for a long time, and although I knew they were a bit harsh I didn't know how truly awful those shocks are until I started running Bilsteins on my Duster. My Duster had a far better ride than my Challenger, even though the Duster had stiffer torsion bars by 30 lb/in. I swapped to Bilsteins on the Challenger and it was a whole new car. Which is why I now tell everyone to toss their KYB's in the garbage if they're going to run a larger torsion bar. Because they're awful.

You basically have to start from the capabilities of your tires, and work in from there. Tire grip sets the wheel rate needs, the wheel rate determines the level of shocks you need, the total grip and wheel rates determine how much chassis stiffening you'll need, etc, etc. The more grip you've got the higher your wheel rates need to be, the better the shocks need to be, and the more stiffening you'll need to keep the chassis from flexing.
 
Tx so much...excellent info. I have built a few of these cars and all were a bit different of course.
My last build was a '70 340 Duster with everything stock and new.I remember how pleased i was with the ride and braking ( 73 "Cuda 2 3/4" callipers and 1" master) when everything was brand new even on poor roads.In all fairness you could not push the car. but for regular driving i liked it.The o.e. shocks did not last 2 years and i replaced the fronts before i sold the car.
I pulled my back wheels today to repaint them and decided now is a good time to start experimenting.So because the rear wheels are off anyway i took the rear Bilsteins off and new o.e. shocks went on. Just bouncing the car it is noticeably softer in the rear now.So we'll see if this change softens the ride and how much it affects handling.Those Bilsteins are very stiff!
 
Haha, the hotchkis shocks are even stiffer if you're just bouncing on the car or trying to collapse them by hand.

But, keep in mind that those shocks are intended to be paired with heavier torsion bars and springs than stock and are meant to dampen faster movements than what you're putting on them if you just bounce on that suspension or try to collapse them hand. So those movements aren't necessarily indicative of how they act on the car.

As I said earlier, the ride quality of my car with 1.12" torsion bars was better with the hotchkis shocks than the bilsteins, but if you try to compress them by hand you'd think the hotchkis shocks would make it stiffer. Shocks act differently with different load inputs. Or at least the better ones do, because they have a lot of valving to change the dampening depending on how fast the oil in the shock is moving. Which changes with the size and speed of the input. Cheap shocks have less valving, so they act more linearly. If you compared how the KYB's acted when compressed by hand compared to the bilsteins or hotchkis shocks you'd make the wrong decision for what would be best on the car.
 
O.K a short update...I have since rem'd the rear and front bilsteins and installed a set o.e shocks (monroe matics) and most of the harshness is gone.Can't even really feel expansion or large weather cracks now but you can still hear them.My own rural road which is an aged tar and chip would thunk and slap with the Bilsteins is now more comfortable.( I purposely targeted some bad sections just to see)
Funny thing is on a fairly sharp bend in a highway i routinely travel it seems as though i have actually lost some understeer and it tracks better now.
So it appears i'm the first one to give Bilsteins a "thumbs down"...at least for my set up on poor roads.i've only previously heard that they were the be all / end all.
In all fairness i'm sure they would offer superior handling on smooth roads with better tires.
 
.920" bars aren't very big, I found the 1" just suspension torsion bars were still pretty soft with bilsteins, hence the upgrade to 1.12" bars.

But ride quality is subjective. If you upgrade the suspension so the car handles better, it won't ride like an old muscle car anymore either. I don't find that my car rides all that differently from more modern performance type cars, but it certainly doesn't ride anything like a stock muscle car.
 
i have built A bodies w/new .870 ( stock 340) bars and thought they were a bit "oozy" but adequate.
Then i built a Dart with .890 bars and really didn't see much change.The .920 were nos from Mopar way back when and actually mic'd close to .940 but there never was a .940?? so i assumed they were .920's?
The bilsteins i took off came from Firm Feel and have the same stroke as stock B body shocks so i wonder how they would perform on a heavier B body?
But as you say ride is so subjective and what is acceptable to one person may be too stiff for another.
 
ir3333 said:
i have built A bodies w/new .870 ( stock 340) bars and thought they were a bit "oozy" but adequate.
Then i built a Dart with .890 bars and really didn't see much change.The .920 were nos from Mopar way back when and actually mic'd close to .940 but there never was a .940?? so i assumed they were .920's?
The bilsteins i took off came from Firm Feel and have the same stroke as stock B body shocks so i wonder how they would perform on a heavier B body?
But as you say ride is so subjective and what is acceptable to one person may be too stiff for another.
Click to expand...

I thought the Bilsteins did a good job on both my Duster with 1" and 1.12" bars and my Challenger with 1.12" bars. The Hotchkis shocks work a little better on the Duster than the Bilsteins did. On the Challenger I'm still running the Bilsteins, I really like them. But that is a heavier car, and the 1.12" torsion bars on it aren't as stiff (B/E body bars are longer). The 1.12's on the Challenger are 270 lb/in, the 1.12's on the Duster are 300 lb/in because of the length change between them.

But I really think most of it for ride quality is personal preference. If you're used to a muscle car type feel, the larger bars and better shocks will feel stiff. If you're used to more modern cars which have higher wheel rates than the old 70's era cars, the larger bars and improved shocks will feel normal. I can't stand the floaty, totally insulated feel you get from the 70's cars. I want to know what my car is doing, and steering with my pinky finger while floating and swaying down the road doesn't cut it. But that's just me.
 
World of difference between rural roads in snow country and California roads, if you drive some roads rural North East some are not much better than a goat path. Have had what
I feel is a decent compromise with .89 bars and KYB, front and rear torque boxes frame
connectors, boxed LCA, shock tower to cowl braces, dearched SS springs, F and R sway bars, 225 60 15 tires provide a little cushion and best mod
for me was a strut brace 3/8 treaded rod tapped into the nose of the PS
box and welded to the front frame rail. All these mods can be fabricated from scrap and take almost all rattles squeeks and other noises away when driving on **** roads
 
66jim said:
World of difference between rural roads in snow country and California roads, if you drive some roads rural North East some are not much better than a goat path. Have had what
I feel is a decent compromise with .89 bars and KYB, front and rear torque boxes frame
connectors, boxed LCA, shock tower to cowl braces, dearched SS springs, F and R sway bars, 225 60 15 tires provide a little cushion and best mod
for me was a strut brace 3/8 treaded rod tapped into the nose of the PS
box and welded to the front frame rail. All these mods can be fabricated from scrap and take almost all rattles squeeks and other noises away when driving on **** roads
Click to expand...

Really Jim? I guess California doesn't have rural roads in snow country? Give me a break. Probably close to half my miles every year are on rural roads that get snow every winter. California is not all beach and freeway, we have more mountains than most of the north east combined. Of the 200 highest summits in the US, California has 22. You know how many of those top 200 are in the North East? Zero.List of the highest major summits of the United States - Wikipedia

And yes, if you look at any of the "worst roads in the US rankings" you will find California in the top 10 always, and usually in the top 5.

So no, there is not a "big difference" for many drivers in California, myself included. Every time I drive to visit my family I drive 5 miles of user maintained gravel road, because they live out in in BFE. And yes, that's with my Duster. Washboards, potholes, runoff ditches, snow sometimes in the winter if it's not deep enough to need a 4x4 yet. 1.12" torsion bars and all.

KYB shocks are miserable, and I'd never run anything less than 1" diameter torsion bars. Did it, too soft. But I wasn't using them with garbage KYB shocks.

Ride quality is a subjective thing, so if you want to say you like a nice soft ride, just say that. The north east doesn't have the market on crappy roads, so don't dismiss my opinion based on false information. Yes, your roads suck. So do ours. Maybe for different reasons, but pothole is a pothole.
 
If you run anything lower than a 50 series tire in theses parts 18453 you will bend wheels and loose fillings, I did live in Cal. in the 1980s did not see
what you describe, may be way north and east don't know. Anyhow don't get insulted just built your suspension adjusted to what you have
to drive on. I look forward to driving my classic cars but really only from
May thru Oct. before or after they just get the crap beat out of them,save that for my 98 F150.
 
I copied the Green Brick.

It's like losing your virginity to your high school sweetie. And she's a Dallas Cowboys cheerleader.
 
66jim said:
If you run anything lower than a 50 series tire in theses parts 18453 you will bend wheels and loose fillings, I did live in Cal. in the 1980s did not see
what you describe, may be way north and east don't know. Anyhow don't get insulted just built your suspension adjusted to what you have
to drive on. I look forward to driving my classic cars but really only from
May thru Oct. before or after they just get the crap beat out of them,save that for my 98 F150.
Click to expand...

I'm not insulted. It's just pretty obvious you have no clue what you're talking about. California has 386,604 lane miles of road. If you think they're all the same you're delusional. The fact that you think California doesn't have rural, "snow country" roads tells me you don't know anything about it at all.

Run whatever you like on your summer weekend car that never sees bad weather and only hits the road 5 months out of the year. I'd happily put my Duster against any of your public roads in Pleasant Mount, Pennsylvania. I promise it's already been on worse and held up just fine. I wouldn't change my 1.12's for anything smaller, and it's not because I drive roads that are smooth as glass. And my 18's and 275/35/18's do just fine too.

Goat path? Yeah I've done that. I usually drive this one a few times a month. 5 miles of this round trip every time. Year round. And I'm sure you can imagine that the paved roads leading to this aren't great either.
IMG_3226.JPG
IMG_3236.JPG


 
Love the 1.03 on my car full poly bushings front and rear, Rancho 5000 shocks on all four corners, Factory std front bar have dropped it an inch and have fitted smaller bump stops and handles very well. Will be updating steering box to 16.1 soon.
 
67 gt said:
Love the 1.03 on my car full poly bushings front and rear, Rancho 5000 shocks on all four corners, Factory std front bar have dropped it an inch and have fitted smaller bump stops and handles very well. Will be updating steering box to 16.1 soon.
Click to expand...
72bluNblu said:
I'm not insulted. It's just pretty obvious you have no clue what you're talking about. California has 386,604 lane miles of road. If you think they're all the same you're delusional. The fact that you think California doesn't have rural, "snow country" roads tells me you don't know anything about it at all.

Run whatever you like on your summer weekend car that never sees bad weather and only hits the road 5 months out of the year. I'd happily put my Duster against any of your public roads in Pleasant Mount, Pennsylvania. I promise it's already been on worse and held up just fine. I wouldn't change my 1.12's for anything smaller, and it's not because I drive roads that are smooth as glass. And my 18's and 275/35/18's do just fine too.

Goat path? Yeah I've done that. I usually drive this one a few times a month. 5 miles of this round trip every time. Year round. And I'm sure you can imagine that the paved roads leading to this aren't great either.
View attachment 1715088614 View attachment 1715088615

Click to expand...
 
That road looks a freeway compared to the **** here! I am simply trying
to make a point you build accordingly to conditions. A go kart is great
on a go kart track an F1 is great on the streets of Monte Carlo, a Baja truck is great in the desert etc. EVERYTHING other than specialization
is a compromise. I am jealous of your roads! wish I could drive more in
foul weather, but I don't have to as I am retired and have beaters. Dont
really know why your getting your back, this is an open forum, this is my experience and opinion that's it. Glad your happy with your setup but its not the ONLY way to go. Don't need a F in photo/geography lesson.
Traveled/worked all over the US Canada South America and Europe for 35 years
 
66jim said:
That road looks a freeway compared to the **** here! I am simply trying
to make a point you build accordingly to conditions. A go kart is great
on a go kart track an F1 is great on the streets of Monte Carlo, a Baja truck is great in the desert etc. EVERYTHING other than specialization
is a compromise. I am jealous of your roads! wish I could drive more in
foul weather, but I don't have to as I am retired and have beaters. Dont
really know why your getting your back, this is an open forum, this is my experience and opinion that's it. Glad your happy with your setup but its not the ONLY way to go. Don't need a F in photo/geography lesson.
Traveled/worked all over the US Canada South America and Europe for 35 years
Click to expand...

One lane single track gravel is a freeway huh? Wow, you are delusional. Just because you can't see the 4" tall rocks sticking out of that road because the video is from a phone on the dash through the rain doesn't mean they aren't there. Because they are, I've killed oil pans on them before. I guess next time I'll have to put a GoPro on my front valance or something. I've broken spring eye bolts, wiped out UCA heim joints in 7k miles, and even busted a tubular LCA (ok, that was mostly a crappy weld). All on California roads.

You are right, suspension is always a compromise. If you want a squishy soft ride, you sacrifice handling. If you want great handling, you will not get a squishy soft OE muscle car ride, even if you set things up right. But if you run KYB's, you sacrifice both handling AND ride quality. My set up may not be for everyone, that's fine. I usually don't even recommend the 1.12's I run to people that drive on the street. But KYB's shouldn't be for anyone. I've run them, probably for close to 50k miles on my Challenger. In the past I've even told people on this forum they were ok (really sorry about that! :eek:). Then I bought real shocks, and found out just how awful KYB's really are. Just buy OE style Gabriel's, at least you'll get a soft ride. KYB's are for garbage cans, not cars.

Like I said, ride quality is subjective. I like my cars to handle, and I don't set them up that way because California has great roads. I also don't drive my car year round because I have to. I could pay cash for a brand new car tomorrow, and I could buy a fleet of beaters if I wanted to. I LIKE driving my car year round, even if that means driving it in poor conditions. It's a choice, not a necessity. You on the other hand prefer a soft ride, that's obvious. Don't blame it on your roads, just own it. Nothing wrong with that, you're happy sacrificing good handling for a softer ride.

I'm coming back at you in an open forum because this thread is for people choosing torsion bar sizes and suspension set ups. And the crap you are saying about running larger torsion bars simply isn't true, not if you actually set your suspension up properly, match components, etc. If I have to show that by providing evidence of the roads I drive, I will absolutely continue to do so. I don't care what you run. You want to run awful KYB's and think you need tiny torsion bars, go ahead. Don't believe me that your issue is those horrible shocks and not your road conditions, it doesn't hurt my back any at all. But don't crap on my set up because your car is set up poorly, even for a soft ride. And don't tell other people my set up won't work for your alleged lousy roads. Because you're wrong about that too, regardless of what your personal opinion may be.

Worst roads in the US by city. San Francisco and LA for the win (Federal Highway Administration 2016 report, analysis by TRIP).
These cities have the worst roads in America

Worst roads by state- California 3rd, Pennsylvania 6th (Ranked by % of roads in poor condition, from a 2017 report from the American Society of Civil Engineers)
The 8 states with the worst roads in the US

Worst roads by state- California 7, Pennsylvania 16 (ranked by percentage of roads in poor AND mediocre condition, Federal Highway Administration report, probably the same 2016 report as the first article)
Worst Roads in America

More TRIP report data, this time for rural roads, like your PA "goat paths". Well, the data says otherwise, and not by a small margin either. 2017 report, 2015 data... TRIP
Screen Shot 2017-09-03 at 4.57.44 PM.png
 
You must log in or register to reply here.
-

Back
Top