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Choosing torsion bars
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Author:  MOUSETRAP [ Sun Dec 21, 2014 5:18 pm ]
Post subject:  Choosing torsion bars
My car is 63 valiant wagon /6 no ac .. BUT a heavy blower and I am a heavy guy I'm 350lbs with a goal of 225lbs .. I also have ss leafs and radial tires
I see the diff size tortion bars and under stand I don't want a ride like a dump truck .. Plan to run the drags a few times a year few car shows/cruise nights short trips 20 to 60 miles round trip
Questions
1. should the vehicle be weighed on set of scales to determine what weight bars ?
2. Would it be possible to want different rate bars left n right or is that a big NO NO ?
3. Is it better to run lighter bars maxed wound up or Heavier bars set light wound down ?
Thank you all very much
Author:  wjajr [ Sun Dec 21, 2014 6:14 pm ]
Post subject: 
Quote:
2. Would it be possible to want different rate bars left n right or is that a big NO NO ?
Don't mix spring rates it really screws up handling. My 67 Dart had a /6 bar on one side, and a v8 bar on the other. When /6 side was loaded car wallowed like a pig, turn the other way loading up stiffer side and car didn't wallow as much; driving down the road on crown road or driving through the twisties was scary.

You can search torsion bars here on the site for a zillion driving impressions.

I can say after a full suspension rebuild on the Dart; installing 0.940" bars, six leaf rear springs, all new bushings, a 1.25" aftermarket sway bar, and rebuilt PS gear to firm-feel stiffer steering the car now handles like a modern car, but not as stiff as my 07 Chrysler 300C. Money well spent, car is now a pleasure to drive, no brake dive, no keeling over in tight turns, and no bottoming out.
Author:  Dan-o [ Sun Dec 21, 2014 6:24 pm ]
Post subject: 
I'd put a 1.06 bar on them with a quality shock (Hotchkis Suspension has the BEST shock setup for Mopars right now). The shock being tuned to the spring rate and chassis is far more important than the rate of the spring.
Author:  Pierre [ Mon Dec 22, 2014 1:18 am ]
Post subject: 
I second the quality shock. My duster has... I forget the size, I want to say 0.890" bars with kyb gas-a-just shocks. Demon has one size up ... 0.920... 0.940 maybe bars.. with Bilstein RCD Classics. The dusters ride is noticeably harsher. Almost wish I would have done the 1" bars on it.
Author:  nm9stheham [ Mon Dec 22, 2014 11:28 am ]
Post subject: 
It is not the quality of the shock per se (though it does have to be good quailty IMO), but the match of the shock rate AND the valving settings vs the spring rate that produces 'best' handling. Using the Hotchkiss shocks with the 1.06" bars seems to be a good rate match.

But, using a stiffer, thicker bar eventually runs into one compromise, and that is working suspension travel. A thick bar will not actually limit suspension travel (as in the control arms will not move far enough), but on a rough road, the suspension will not move as much as it should. This is not a problem if you drive in certain parts of the country where the terrain is pretty flat, and the roads are pretty smooth. But if you live where roads have a lot of surface roughness and older, uneven roadbeds, then you will find that the tire compliance with these rough, uneven conidtions will not be good. In that case, using bars in the range of .89, .94, or thereabouts is a better choice, and the Bilsteins seem to be a better rate match of that spring rate.

So I would suggest that you look at your terrain and roads when you make your choice. And, the thicker bars and matching shocks will be stiffer and have a more jarring ride. Newer seats in a car can ameliorate much of this, as well as usingn OEM style rubber bushings rather than poly ones, and older folks will be more effected by a harsh ride, so opinions will vary all over the map as to if 1" or larger bars are too stiff/rough or are perfect! That is always the issue in reading views on this topic: separating objectivity from subjectivity is nigh well impossible, and objective data (like drag time slips) is not available to most people.

For drag racing, the best to use is the /6 bars. They actually store more energy at static height than thicker bars, and as such, will help to 'throw' the front end into the air at launch and help weight transfer to the rear. And the ideal shocks for drag racing have a very different ratio of compression/rebound valving than good road shocks. So, if you are going to drag race only occassionally, then you likely need to just compromise best drag race setup in favor of a better road handling package.
Author:  nm9stheham [ Mon Dec 22, 2014 11:29 am ]
Post subject: 
Quote:
I second the quality shock. My duster has... I forget the size, I want to say 0.890" bars with kyb gas-a-just shocks. Demon has one size up ... 0.920... 0.940 maybe bars.. with Bilstein RCD Classics. The dusters ride is noticeably harsher. Almost wish I would have done the 1" bars on it.
The Duster's harsher feel is likely the KYB's.....not the spring rate/bar size.
Author:  Pierre [ Mon Dec 22, 2014 11:42 am ]
Post subject: 
Quote:
The Duster's harsher feel is likely the KYB's.....not the spring rate/bar size.
Yep... I was trying to say a skinnier bar will seem harsher (anti-intuitive?) if not paired with a shock that can match it.
Author:  sandy in BC [ Mon Dec 22, 2014 2:19 pm ]
Post subject: 
In our rough road part of the world I like the premium shock,,,,big sway bar...stock T bar combination. The softer bar lets the shock show its stuff.
Author:  nm9stheham [ Mon Dec 22, 2014 3:40 pm ]
Post subject: 
Quote:
Quote:
The Duster's harsher feel is likely the KYB's.....not the spring rate/bar size.
Yep... I was trying to say a skinnier bar will seem harsher (anti-intuitive?) if not paired with a shock that can match it.
I guess what I am thinking is that the KYB valving does not seem to be as able to work compliantly with sharp bumps. I rallied on some KYB's years ago and Bilsteins worked much better in keeping the tires in contact with a rough surface. The KYB's seem to act like a step above a high end Monroe or thereabouts.

There is a lot of difference valving designs in shocks, gas pressures, and so forth. If you ever had the chance to drive at speed on a rough road on some higher end rally shocks like 50 MM DMS or even 40 MM Bilsteins, it would be an eye-opener. (And I am just a sutdent in the arena and rally shock user, not a dedicated shock guy....)
Author:  Pierre [ Mon Dec 22, 2014 6:28 pm ]
Post subject: 
The KYB's were ok when the duster had the stock bars but once the bars were swapped to the 0.890s they got hairy. I sure wouldn't want to try the kyb's with the 940s.

There's a lot of subjectivity to it but I think the sum of it is don't use kyb's beyond anything stock. Be prepared for some sticker shock though once you start getting to the fancier stuff.
Author:  Zoom3r [ Mon Jun 04, 2018 8:48 pm ]
Post subject:  Re: Choosing torsion bars
Hi! I have a related issue. Is it recommended to put on only the torsion bars and shocks without the sway bars? I’m thinking to get stiffer torsion bars and better shocks but there seem to be quite a lot of options like Hotchkis, Bilstein, KYB. So what's good to use with the torsion bars? Also, will the dampers control high rate springs but still ride well?
Author:  ntsqd [ Tue Jun 05, 2018 9:17 am ]
Post subject:  Re: Choosing torsion bars
Stock '65 \6 t-bars and KYB's. The KYB's suck, they'll be going on CraigsList soon. The car's line is upset in a rough corner and each axle as it passes over the rough spot 'steps-out' widening the line thru the corner. This happens even if only the inner or the outer tires are affected by the rough pavement. No surface tracking by the tire at all.

I am curious as to how the Bilsteins perform. I've extensive experience with Bilsteins (& Fox's/SAW's/Kings) in an off-road setting and I think deflective disc valving is the way to go. At least in large travel suspensions, yet to see how well the design works in short travel suspensions. Interesting to note that Bilstein themselves does not have a listing for A Bodies. It takes a suspension company whose origins is in off-road (Race Car Dynamics) to offer a Bilstein for these cars.

As to t-bar size, at this point I don't see a need to increase the bar size. The car needs more sway-bar first.

In "Competition Car Suspension" Allan Staniforth goes deep into choosing the wheel rate, which thru the Motion Ratio becomes the Spring Rate. https://www.amazon.com/s/ref=nb_sb_noss ... Staniforth
Author:  Dart270 [ Tue Jun 05, 2018 10:38 am ]
Post subject:  Re: Choosing torsion bars
To original poster: You should be fine with stock tbars for your needs. I would go with good shocks (Bilsteins or Hotchkis) and a 1 1/8" front sway bar before I would change tbars. Make sure to set your ride height even on both sides and get a wheel alignment too. If you want to lower the car a lot, then you will want stiffer tbars. Look at FSM for stock ride height adjustment method and specs.

Lou
Author:  Pierre [ Tue Jun 05, 2018 6:59 pm ]
Post subject:  Re: Choosing torsion bars
KYB's may be good for a stock replacement type app. If your stockers are worn then sure you'll notice an improvement. If your doing upgrades and getting bigger bars etc and expect performance, don't bother. I don't have any experience with hotchkis, but I have two similar cars one with kyb gas adjust's and one with a bilstien set. Forget the series... I think it' sthe "classic car" line that I got from firm feel. The difference is noticeable even in daily driving. Definitely a case of you get what you pay for here.
Author:  jcc [ Sat Jun 23, 2018 8:33 am ]
Post subject:  Re:
Quote:
I'd put a 1.06 bar on them with a quality shock (Hotchkis Suspension has the BEST shock setup for Mopars right now). The shock being tuned to the spring rate and chassis is far more important than the rate of the spring.
This would be the direction I would go with what you shared.
KYB being useful as a useful shock is like winning the lottery, possible, but on the rare side.
The fear of using too high rate of TB, over the years, most thought anything nearing 1" was for a dump truck, now 1" and larger are in the running. Also note, very few have ever reported they went too big, and most ALWAYS wonder what bigger would drive like. Even Hotchkis originally shied away from 1" TB, something about spot welds breaking (seriously and erroneous IMO).

If you are running on rough roads, then this not a "handling" question, but more of a "ride" question, get a Caddy? :lol:
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