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Torsion Bar & Strut Bar

14K views 36 replies 9 participants last post by  cgawelko 
#1 ·
I get the idea of the strut tower bar, my Protege included in from the factory. But on the Rio the strut towers are so close to the back of the engine bar that I don't think it would make any difference at all.

And, what is the point of putting a rear lower torsion bar on a car with a solid rear end?
 
#8 ·
i had a Neuspeed Strut Tower Bar on my previous vehicle, Honda CR-V, and so did a lot of other V owners on the Hondasuv forums. It definitely made a difference in cornering. i've looked for some for my Sportage, but none available. :(
 
#11 ·
the struts go through the body, so i guess you could say it connects the struts and the body.
 
#13 ·
The theory is that the top of the strut towers flex. Having a strut tower bar fixes that. Technically the Front Chassis brace does not stop that, (im just speaking theoretically.)

So like I said in the beginning, both the strut tower bar and front chassis brace are right under the end of the windscreen, so there should be practically no flex in the stock body set-up. Its not like we have long front ends that are twisting under cornering, hence the need for front braces.
 
#14 ·
Having done my third time at the track, this time with dedicated tires, there is absolutely no reason to install a front strut tower or any other upper stiffening bar. The stock car has plenty of under-steer and this type of mod would increase under-steer, so its completely useless.

As far as rear sway/torsion bars, I've heard all the arguments for them, but they do not make any sense. Car needs the back to be MORE flex, not less.
 
#16 · (Edited)
As far as rear sway/torsion bars, I've heard all the arguments for them, but they do not make any sense. Car needs the back to be MORE flex, not less.
The rear needs to be stiffer actually. Having a really stiff rear end promotes oversteer in a front wheel drive car, which is what we need, as you can physically hear the chassis flexing (plastic on plastic creaking sounds under hard cornering).
Consequently, going too stiff will result in a vicious lift off oversteer characteristic. So you want something stiff, but not too stiff.
All the torsion/sway bar is doing is keeping the suspension geometry constant at the rear, rather than the car leaning on one side more than the other.

I haven't tracked my car yet, but doing touge runs with it has yielded the need for a torsion bar. Having the car understeer towards a cliff edge isn't exactly ideal.

If you want more flex, a Toyota Supra aerotop is what you're after. Steers like wet cardboard because of this "flex" you would prefer.
 
#20 ·
Thanks for taking the time.

So you are referring to the areas where the springs sit? (the two flexiest parts of the rear suspension.)? So these would flex up and down, so a torsion bar would stop this. If these actually flex, that would make sense. My brother has a straight torsion bar on the back of his Abarth.

The ones that bolt to the bottom of the spring area and then bend and curve around to beam, seem like they are mimicking an anti-roll bar. And yes, for the street, they are unnecessary.

You can see the body-roll on my car in this picture. This is a hard right corner after a long straight. You can see the inside tire 'lifting.' The whole side of the car needs to come down.
 

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#21 ·
no problem! It's helpful for all of us to know how our cars work in order to make them faster :)

Correct, they can also flex left and right, which is where the majority of the problem lies. The torsion bar stops (or at least lessens, depending on how thick the bar is) the left-right flex and keeps the spring centres constant almost all the time. But it also stops excess vertical movement to keep the car more composed.

The design of the torsion bar is critical, as like with our torsion beam suspension style, you can create different spring rates and handling characteristics. A straight bar is ultimately the most solid, which is what probably causes your brother's Abarth to feel out of control and makes it favour oversteer.

They do mimic an anti roll bar, and they do quite a good job at it. If you have the income to do so, it's worth purchasing some different brands/types of torsion bars and seeing which one works best for you. I'm currently busy with uni, but I'm also in the process of designing a slightly more "hills run" oriented bar. I'll let you know when I've got it sorted though.

From your picture, it appears the torsion bar is doing its job well, as you've essentially drawn a straight line directly across the spring bottoms. In terms of body roll, you'll need to invest in a stiffer spring/damper. I'm guessing the Canadian delivered Rios have the same spring rates as the American ones, which are really quite a soft setup. It might even be worth getting in contact with Kia Australia to find out if you can purchase an Australian tuned setup, because ours is quite a bit stiffer than the rest of the world's.
 
#22 ·
Kia Rio springs as a soft setup?? LOL compared to what? A 1940 Willys? Ive been looking for more comfortable springs for this thing because im sick of being tossed around. The seats are so laughably inadequate that it makes the suspension feel worse. I have antiroll bars on my lexus and Tanabe DF210s and its much softer and comfortable than the Kia lol If anyone knows a soft nice comfortable suspension for the Rio that can also raise the car up about an inch (2-3cm) let me know!
 
#23 ·
You're comparing an 1100kg hatchback to a 1700kg big plush luxurious car. No matter what springs you put on it, the dampers are always going to be set up softer. What you're feeling is a really stiff compression (also known as bump) setting on the Rio, along with what seems to be a mid/quick rebound setting. Your lexus probably has a soft compression and slow/mid rebound setting, making it feel more wafty, despite your lowered springs.
Physics also dictates that even putting like for like suspension rates, the Rio will always feel harsher because an extra 600kg will compress a spring more. F= -kx is the formula we're referring to here, Hooke's law.
x = displacement from static sag (neutral position)
F = force required to compress the spring (or the force required by the spring to re-extend)
k = spring constant

if you're after softer, look into damper settings along with a spring with the same rate, but longer. :nerd: (I dunno where you would find that though!)
 
#24 ·
Well I need taller because Kia made the really smart move to put a almost 2" black lip on the front, so when it snows and since the kia is weak and can barely get out of its own way, when the snow builds up, that lip snags and then it gets stuck. Gets old pretty fast lol

And the Tanabe DF210s are a rough spring... .when I put them on it was a nightmare. I went from cloud, to go kart..... and then the kia is more like a piece of plywood on some office chair casters lol
 
#26 ·
I think it might be possible to just rip the lip off, if I remember correctly, its screwed in with some silly small screws in a really difficult location. You'll probably have to remove bumper though, but still, if it saves you from having to go out and buy springs!

But, you *could* always do this:

 
#27 ·
I need that Kia in my life. lol They have a few LS400s that are lifted on 31s, but the Lexus in snow with all the adders on it and no snow tires gets old, so we take the kia. and even for being a tin can with wheels, it slides all over the place. So I need that guys suspension, and some wheels like that for the winter lol
 
#28 ·
Its not a fucking Tin Can with wheels dick-ass!

My wife and I both drive our Rio through Ontario winters, with dedicated winter wheels and tires and the car is great in the snow. Maybe you need to learn how to drive according to conditions.
 
#29 ·
It is a tin can with wheels. Its hardly insulated and made as cheaply as possible. Thats what the rio is. Its an econobox of cheap. And I can drive plenty fine in the winter, the kia slides, but doesnt mean I cant control it. I have yet to be in any accidents with it, or lose control of it. Havnt slid into any intersections yet I see people in Subarus do it all the time.

Easier in the lexus. flick the wheel, punch the gas and change direction. Hell I had a mitsubishi station wagon that was a DREAM in the snow compared to the Rio.
 
#30 ·
I'll have to agree with the 'econobox of cheap' assessment. Of the vehicles we own, the Rio is the least solid and the most cheaply made......even when compared to our Ford Ranger. I'd rather drive any of the other three vehicles in bad weather.
 
#31 ·
The worst part about that assessment. Is that I pay $377.88 a month and 18% interest to own this car. LOL! I was going to take a video of me pushing on the panels on the kia to see them flex, and then doing it again on the 2008 VW Eos, and then on the 93 Lexus. But I hate the Eos even more than I hate the Kia and I cant stand to think anything on it is better.
 
#32 ·
You can't be serious about the $377.88 a month and 18%? Why would you do that?

Just because the panels flex when you push on them doesn't mean its a cheap car. I just went and did it on a brand new 5Series in the parking lot. Sheet metal is much thinner on all cars now-a-day because the skin isn't what keeps the car together and strong and safe. Its one of the least expensive cars on the North American market, its going to made on a budget, Duh!

How a car 'feels' is subjective. You go golfing in the Lexus then get in the Kia, sure its going to feel 'cheap.' Going from my friends brand new Lancer to my Rio, my Kia is a Rolls in comparison, the lancer feels cheap and full of crappy hard plastic.

You are on a Kia forum and putting the cars down, just because you own one, have some tact.

Go tot he Lexus forums and talk about putters and how the Dynamic Laser Cruise Control might be giving you nut cancer.

You 'slide' around? On purpose? Get off the road! Get a life.
 
#33 ·
Look its cheap, you get what you pay for, that said there are plenty of louder cars out there for twice the price.

I came out of an Subaru into this, my suby was loud as f*** the Rio is library compared to that.

I am not Kia's biggest fan, but if you want something that doesn't hurt the wallet (unless you go for 3 bills at 18%, that is your fault) and get you from A-to-B anything in this price range is going to be pretty similar.

As for winter driving throw some winters on it and deal with it. Its not great but its not that bad either.
 
#34 ·
Well yes I do pay $377.88 at 18% interest because it beats the $246 every two weeks at 26.8% I was paying for my 2004 Lancer Ralliart that was my baby. I put almost $2000 in just custom made interior parts into it, to find out it was totally twice and the documents I signed were changed so when the BBB requested copies it showed I signed that it had a Salvage title, even though my wife signed those papers too saying it was clean and suddenly her signature is missing. So I took the car back to that sh^% pile dealership, and needed a car and Kia financed me when nobody else would. Took the other dealer into court precedings and they dropped the charges for $8000 because they had false documents and I had proof. Still hit my credit as a repo.

2 years later and not a single late payment, it doesnt bother me. I could refinance it, but I dont feel like sticking myself into it even more. Car is already upside down in value because its such a value holding wonder.

I put down the lexus too. I abuse the sh$% out of that car. It has been wrecked twice in the same spot, nothing a crowbar didnt fix. almost 200k HARD miles. Still change the oil every 15k. Have to change tires every 3 months because they just cant hold. Its still a fat pig with HIGHLY overengineered crap that I have removed and piled up in the garage to strip it down from 4800lbs.

And yes. I slide my car on purpose. Just like people drive their cars off road on purpose, or do burnouts on purpose. Its what I built it to do. Eat tires and go fast. Run hard and put away wet. If that upsets you, refer to my profile picture.
 
#35 ·
My question of cgawelko, if the Rio is such a cheap unsatisfactory poorly made piece of crap why did you buy it in the first place, you surely took a test drive and unless you were drunk or high when you checked it out some of the shortcomings you complain about had to be present.

I cannot give any of your posts much credence anyway, you come across to me like an immature 16 year old, I have to whole heartedly agree with P5Myk, grow up get a life.

Pat.
 
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