Whats the benefits of changing torsion bars

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straightlinespeed

straightlinespeed

Sometimes I pretend to be normal
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Im still running the stock torsion bars in my 71 Scamp originally a 318.

Ive been seeing that people are changing out torsion bars and Im not really sure why people change to larger bars. Can someone explain to me why you switch and how to pick the proper bar.
 
The larger the torsion bars' diameter, the more torsion it provides. A heavier engine needs a larger diameter bar to "hold" up the front. Changing to a larger bar will make the front end have a "stiffer" ride having less body roll in turns and less bottoming out.
 
It's called a corner. They are fun to take. They need bigger bars. The end.
 
1" bars seem to do the trick, just suspension has a good deal, $188 shipped, discount code 'shopalizer'.
 
I'd say offhand it's difficult to get bars that are too big. I "scored" a big dia set in a body I bought, but I still plan (at least a front) roll bar.

You understand how roll bars work? Every car should have them.
 
How they work may make it easier to understand. A torsion bar is a length of steel and it has hexagonal shaped ends. One hex is secured to the frame (body) and the other end is fixed to the lower control arm (LCA). As the car's weight pushes down, it rotates the LCA and it tries to twist the torsion bar. The larger the diameter, the more that it resists the twisting. Additionally, there is an adjustable lever that turns the LCA's position on the torsion bar thus raising or lowering the front end of the car.
 
67Dart273 said:
I'd say offhand it's difficult to get bars that are too big. I "scored" a big dia set in a body I bought, but I still plan (at least a front) roll bar.

You understand how roll bars work? Every car should have them.
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Sway bar? Normally I think of roll bar being inside the car
 
Well. I haven't swapped my stock bars w/318 and my front is plenty stiff. Just swapped kyb gas a just shocks and installed helwig swaybar. Car handles really well and its still comfortable to ride, we have bad roads here. But if i would put bigger engine i definitely would swap to bigger bars
 
Torsion bar does the same thing as a coil spring except coil springs can have a variable rate via coil circumference and spacing differences.
Not everyone needs stronger torsion bars. Those that have very low hanging headers or very large wheel & tire crammed under definitely need them.
Others get vast improvement in handling by adding a stabilizer bar where there isn't/wasn't one.
 
..i think there are 2 camps on this.
large torsion bars and standard sway bar
smaller torsion bars would use a larger sway bar.
.. i have only used standard stuff
 
Well I definitely want to add a sway bar, that is on my to do list. If I change torsion bars down the road do you have to realign the vehicle?
 
straightlinespeed said:
Well I definitely want to add a sway bar, that is on my to do list. If I change torsion bars down the road do you have to realign the vehicle?
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Alignment is done sitting still so no not absolutely.
if you can get the height adjustment back to exactly where it was,
other settings remain unchanged.
 
Yep. If you measure your height you can get it close but I would spend the money for a good aleignment.
 
As the years have rolled on from the mid-sixties or earlier to present time suspensions have gotten stiffer, more competent, and able to provide vastly better handling. By changing to stiffer a torsion bar, adding a front anti sway bar, and replacing worn bushings & front end parts, sagging rear springs and shocks these suspensions will provide close to modern car handling. Additional up grades would be sub-frame connectors, and rebuilt PS steering gear to stage two that produces a less boosted modern power steering feel if equipped.

I made these changes to my 67 rag top, and the car is a real pleasure to drive now. No more brake dive, wallowing in curves, floating over rough road, and hitting bump stops, only nice flat cornering, with predictable neutral handling, and comfortable ride.
 
zhandfull said:
Sway bar? Normally I think of roll bar being inside the car
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OK anti roll bar, stabilizer bar

If you REALLY wannna get nit-picky, wouldn't a "sway bar" indicate that it would "cause sway," and therefore should be an "anti sway" bar?
 
Whats the benefits of changing torsion bars

Torsion bars are essentially springs. Like all springs they fatigue with duty cycles and age. this fatigue will eventually lead to fracture/breakage. Nothing lasts forever....
 
Not really true because springs can be projected for nearly infinate life within the elastic limit. Torsion bars don't exceed the yield point therefore will not normally fail simply due to use. Leaf and coil spings can exceed the yield point and therefore potentially can fail due near stress risers. A torsion bar with a stress riser like a cut or chip is in the same boat.
 
Mattax said:
Not really true because springs can be projected for nearly infinate life within the elastic limit. Torsion bars don't exceed the yield point therefore will not normally fail simply due to use. Leaf and coil spings can exceed the yield point and therefore potentially can fail due near stress risers. A torsion bar with a stress riser like a cut or chip is in the same boat.
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Springs get older and weaker with age and duty cycles. Period!

There are no "wonder springs" that last forever. Everything fatigues and gets weaker. This is why rear leaf springs sag with age.

We had many broken torsion bars at the shop where I was a mechanic in college where they had broken. They were used to do front end inspections and look for loose parts before being aligned. A torsion bar is just a bar of steel used as a spring.


If YOU choose to run original springs and torsion bars, that is YOUR call.

I however, choose to replace MY 40 - 50 year old springs and torsion bars on MY car....

If you believe that the used parts are still good, I would be happy to sell you my junk when I am done with it.... :D
 
straightlinespeed said:
Ive been seeing that people are changing out torsion bars and Im not really sure why people change to larger bars. Can someone explain to me why you switch and how to pick the proper bar.
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People switch for various reasons. The best reason is that stickier tires are being used that originally came with the car. While cornering the car now has better traction, and the car rolls more. Body roll is disconcerting to drivers (varies with driver) and also can produce less desireable camber. This in turn takes away from the tire's effectiveness.

This must be balanced against road conditions. Making either the anti-sway bar or the t-bars too stiff will reduce the ability of the wheel to smoothly stay in contact with the road. Also even on good, smooth grippy pavement (eg concrete) a stiffer suspension loads the the outer tire more. Eventually it gets overloaded. So there is a limit to the effectiveness of stiffening.

For general street use on typical modern radial tires, a front sway bar is probably the best first move if there is none. Next would be the stiffest factory t-bars, and or something up to 1.03" diameter t-bar depending on front wieght of the car. To the above, add a slightly more aggressive camber and caster. At least the most aggressive side of the factory specs.

On the other hand, if you're driving on sand, or in snow, then stiffer is not better. Nor a is a big bar an advantage for drag racing.
 
krazykuda said:
Springs get older and weaker with age and duty cycles. Period!

There are no "wonder springs" that last forever. Everything fatigues and gets weaker. This is why rear leaf springs sag with age.

We had many broken torsion bars at the shop where I was a mechanic in college where they had broken. They were used to do front end inspections and look for loose parts before being aligned. A torsion bar is just a bar of steel used as a spring.
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Comparing a leaf spring to a torsion bar isn't an equal comparison, apples to oranges. Completely different design and function.

As far as getting "weaker", they actually don't. The effective spring rate remains THE SAME over the life of the torsion bar. It's just physics.

They do, however, sag. The bars settle over time, and although the spring rate remains the same, the car loses ride height. With torsion bars as old as the originals, it may even get to the point that the torsion bar adjusters aren't able to compensate. But the car sitting on the bumpstops isn't because the bars got weaker, its because the indexing has sagged.

And of course, damaged springs fail. They should not fail from use, as they never exceed their elastic limit in the design of the suspension (as was already pointed out). But, a little nick or chip can cause a failure, and I'd bet that the failed bars that you saw had damage to them (not wear).

Regardless, you should change the original bars. The original spring rates and alignment specs were based on hockey puck hard bias ply tires. Even just switching to old design radials, like the BFG T/A, should mean an upgrade in spring rate and alignment.

Changing to a modern design/compound tire really demands a change in torsion bars, the change in traction is HUGE. Modern cars being able to pull 1 lateral G on the skidpad has almost everything to do with the traction coefficient of modern compound tires, and very little to do with changes in actual suspension design. That increase in traction increases the loads transfered to the suspension because the tires are gripping instead of sliding, which requires the use of larger spring rates to manage the increased loads. It also begs an improvement in stopping power, as improved traction coefficients mean that the little drum brakes will no longer lock up the wheels.

1" torsion bars are a very nice upgrade to most cars, I ran a set on my 318 Duster for a bit. I found them too soft still myself, and have since upgraded again to 1.12" bars. Those won't be for everyone, as they will provide a very stiff ride. But not everyone runs 275 wide tires front and back either, and the additional spring rate comes in handy when managing that kind of traction.
 
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