Found the limits of the old Altima

[Checkered-Member]

As the old saying goes: A chain is only as strong as its weakest linkSame applies to suspension.

So a few nights ago, I was driving where the 23 meets the 101, it a banked road, all I could pull on it was 95 when the front of the car started swaying and loosing control.

The reason for that is that don’t have an aftermarket front anti sway bar, because one is not offered for the Altima.

So a custom one is the most logical solution, but how, should I take my sway bar to a metal bending shop and have them bend one same size, but with a stiffer metal?

or smelt me a new one using the OEM sway bar as mold.

Any other options?

[Nismo_Freak]

Any reasoning behind why you think a front sway bar will solve your probelm?

And by "Swaying" what do you mean?

Was their understeer/oversteer present?

Was the vehicle hopping at all?

How hard would you say the front suspension was compressed?

Tire size/brand for both front and rear?

[Checkered-Member]

^ holy crap....ok

1. while the rear remained flat, the front was banking very hard as I was trying to correct the cars direction, and couldn’t do it effectively, at that speed.

2. don’t know the difference between over-steer and under-steer…

3. Hoping? None

4. Wasn’t compressed at all.

5. Hankook Ventus HRII H405 (225/40/18) front and back.

[SmithSR]

There's the problem! Put on some 140 wear rating Bridgestones and try again! Seriously.

Phil

[Checkered-Member]

There's the problem! Put on some 140 wear rating Bridgestones and try again! Seriously.

Phil

The tires are fine, they grip, just the dam front sway bar.

Anyone can give me a trait answer?

[SmithSR]

Hang on. For some reference, read Q45tech's endless supply of posts re: sway bars.

From there, let's get a better understanding of what you're asking, because sometimes it's very hard to explain what a car is doing. All we can do it take a few sentences that you've given and try to imagine, extract a dynamic the vehicle is experiencing. Entire books are written on such subjects.

From what we've read, you're under the impression that while cornering(highway junction?) on a banked road, at the speed of 95mph, the car begins to slip up & out of your intended line.

Is this correct?

If it is, then we assume that at the speed of 95ph, on a long, banked curve, the outside(high bank side) suspension is under compression already.(loaded)

Body roll is for the most part static while actually travelling through the turn, as the outside (in relation to the banked turn) suspension becomes loaded as the car settles into the 95mph turn. (body roll should have already occured)

Turn in on this 95mph banked road is where roll stiffness comes into play.

Road holding (at the point of already committing the car & driving the turn) is a function of friction coefficients.(tires)

I know my first reply may have seemed post-whore-ish in nature, but from the info you've given, and while I try to imagine the scenario and put into words what I've experienced with FWD at high speed banked sweepers, my original post may not be so far off.

[Nismo_Freak]

The tires are fine, they grip, just the dam front sway bar.

Anyone can give me a trait answer?

What you experienced was understeer. The suspension was doing it's job of keeping you on the road, as designed from the factory.

More than likely this was a result of the front spring rate being unable to adequately maintain suspension compression. Which translates into too much camber gain and a corresponding bump in toe.

You have lowered the roll center faster than the center of gravity in the car (which is why 240's don't handle well when lowered alot). Paired with a set of OEM sway bars this quickly causes limit understeer (does the sidewall of your tire have any white spotting on it?).

While a front sway bar can correct this situation it will cause mid speed understeer. You will need to increase the rear spring rate or the rear sway bar thickness to compensate for the increase in front rate. Typically go with a 1:1 increase but since the car is FWD I would suggest a 15% thicker rear sway setting. This will increase the vehicles tendency to oversteer and may neutralize the handling.

The BEST solution would be to increase the front and rear spring rates as this is where you should focus most of your anti-sway resistance. However for your application I don't know of anything available to do so.

One other thing you might try would be to move the toe out a little in the front (if it's toe-d in you will get understeer but more predicatable handling) and reducing static camber (more towards 0)

[Nismo_Freak]

The tires also are an area you could EASILY improve on.

225/40/18 88H Hankook Ventus HRII H405340AA

These tires have several aspects that are poor for handling performance, I'll explain.

88 - This is the load index for the tire you have now, you should never accept anything below 90 for your vehicle. You could move to a Hankook K104 which has a 92 load rating in the same size. This will give you better performance as well as give the tires more life.

Tread design - the design on the tire you have now is not a sports design, it is more of a touring tire. The high void ratio (open area) in the tire gives the tread alot of squirm area which makes handling feel vague but helps for a smoother loss of traction at the limit. The lack of a center rib in the middle of the tire makes the tire lose alot of it's stability in cornering. And the side blocks on the shoulder have too much space between them.

If you could stomach a little more sidewall I would HIGHLY suggest going with a 225/45/18 Yokohama ES100.

[Checkered-Member]

holy smokes I just got served by two moderators

Let me respond to some comments

Hang on. For some reference, read Q45tech's endless supply of posts re: sway bars.

From there, let's get a better understanding of what you're asking, because sometimes it's very hard to explain what a car is doing. All we can do it take a few sentences that you've given and try to imagine, extract a dynamic the vehicle is experiencing. Entire books are written on such subjects.

From what we've read, you're under the impression that while cornering(highway junction?) on a banked road, at the speed of 95mph, the car begins to slip up & out of your intended line.

Is this correct?

YES exactlyIf it is, then we assume that at the speed of 95mph, on a long, banked curve, the outside(high bank side) suspension is under compression already.(loaded)

Body roll is for the most part static while actually travelling through the turn, as the outside (in relation to the banked turn) suspension becomes loaded as the car settles into the 95mph turn. (body roll should have already occured)

Turn in on this 95mph banked road is where roll stiffness comes into play. I see

Road holding (at the point of already committing the car & driving the turn) is a function of friction coefficients.(tires)

I know my first reply may have seemed post-whore-ish in nature, but from the info you've given, and while I try to imagine the scenario and put into words what I've experienced with FWD at high speed banked sweepers, my original post may not be so far off.

What you experienced was understeer. The suspension was doing it's job of keeping you on the road, as designed from the factory.

ok….

More than likely this was a result of the front spring rate being unable to adequately maintain suspension compression. Which translates into too much camber gain and a corresponding bump in toe.

I think that’s what happened

You have lowered the roll center faster than the center of gravity in the car (which is why 240's don't handle well when lowered alot). Paired with a set of OEM sway bars this quickly causes limit understeer (does the sidewall of your tire have any white spotting on it?).

Yes, a little

While a front sway bar can correct this situation it will cause mid speed understeer. You will need to increase the rear spring rate or the rear sway bar thickness to compensate for the increase in front rate. Typically go with a 1:1 increase but since the car is FWD I would suggest a 15% thicker rear sway setting. This will increase the vehicles tendency to oversteer and may neutralize the handling.

Current rear bar is about 27mm while stock was 19mm

The BEST solution would be to increase the front and rear spring rates as this is where you should focus most of your anti-sway resistance. However for your application I don't know of anything available to do so.



One other thing you might try would be to move the toe out a little in the front (if it's toe-d in you will get understeer but more predicatable handling) and reducing static camber (more towards 0)

oy

The tires also are an area you could EASILY improve on.

225/40/18 88H Hankook Ventus HRII H405340AA

These tires have several aspects that are poor for handling performance, I'll explain.

88 - This is the load index for the tire you have now, you should never accept anything below 90 for your vehicle. You could move to a Hankook K104 which has a 92 load rating in the same size. This will give you better performance as well as give the tires more life.

Tread design - the design on the tire you have now is not a sports design, it is more of a touring tire. The high void ratio (open area) in the tire gives the tread alot of squirm area which makes handling feel vague but helps for a smoother loss of traction at the limit. The lack of a center rib in the middle of the tire makes the tire lose alot of it's stability in cornering. And the side blocks on the shoulder have too much space between them.

If you could stomach a little more sidewall I would HIGHLY suggest going with a 225/45/18 Yokohama ES100.

I see, My tires are up in about 5-10K milesI’m thinking of upgrading to

Pirelli PZero Nero M&S tires

these should be better. What do you guys think?

[Nismo_Freak]

No, go with a true sport compound.

Try the 225/45/18 ES100's ... you'll be happy.

[Exar-Kun]

hell, es-100's would handle better than the kooks...

a 225-45-18 is a bit high sidewall for an altima (imo)... see if you can afford a good grippy 225-40-18 in something like the bridgestone s-03, michellin pilot sport, or goodyear eagle f1 gs-d3...

if you can REALLY afford it(have lots of cash) the new pilot sport 2 is available in the 225-40-18

that'll be my next tire....-chet

[Checkered-Member]

chet is right

I’m not changing my tire size, with the 40's I’m within 1% of the stock size.

but, I need affordable tires, that will last along time, my car is a daily driver I can’t afford to replace my tires every 20K miles.

all the tires you listed have trade rating of 280 and below, that’s unacceptable

[Nismo_Freak]

chet is right

I’m not changing my tire size, with the 40's I’m within 1% of the stock size.

but, I need affordable tires, that will last along time, my car is a daily driver I can’t afford to replace my tires every 20K miles.

all the tires you listed have trade rating of 280 and below, that’s unacceptable

Ratings are set by the tire manufacturer and are thus ... meerly "guidelines" at best. I would go with the ES100's

[Exar-Kun]

"all the tires you listed have trade rating of 280 and below, that’s unacceptable"

then you arnet serious about fixing your problem, are you?

you wanna play, you gotta pay...and your tires are the only thing hitting the ground man...and are almost always your limitation on grip.-chet

[Checkered-Member]

"all the tires you listed have trade rating of 280 and below, that’s unacceptable"

then you arnet serious about fixing your problem, are you?

you wanna play, you gotta pay...and your tires are the only thing hitting the ground man...and are almost always your limitation on grip.-chet

what about trying to make a front sway bar, it will help some...and only a one time expense...so what should i do about that?

[Nismo_Freak]

what about trying to make a front sway bar, it will help some...and only a one time expense...so what should i do about that?

Tires will improve every dynamic of the car... not only handling.

They also will improve the handling more than a sway bar.

Think about it... is it better for handling to make another half inch of rubber touch the ground. Or is it better to improve the grip of the 4 inches already touching the ground.

[Checkered-Member]

Tires will improve every dynamic of the car... not only handling.

They also will improve the handling more than a sway bar.

Think about it... is it better for handling to make another half inch of rubber touch the ground. Or is it better to improve the grip of the 4 inches already touching the ground.

Well when I got a rear bar it I made a huge difference, so I want to get a front bar

I understand that tires will make a huge difference, but you guys are asking me to pay 800 bucks for tires every year…

now I’m getting frustrated, should I go to another Forum and ask this question?, if you guys aren't going to be helpful

[SmithSR]

Why would you need to go to another forum? 3 guys with jobs in the industry are all telling you the same thing.

What aren't we answering?

Is your question, how can you get an aftermarket front anti-sway bar?

[Checkered-Member]

Why would you need to go to another forum? 3 guys with jobs in the industry are all telling you the same thing.

What aren't we answering?

Is your question, how can you get an aftermarket front anti-sway bar?

you guys got your point a cross, thank you, I will look into getting better tires, back to the original question: how can I make a custom aftermarket anti-sway bar?

[Exar-Kun]

call up JWT they may be able to make one, or take your old bar to a metal fabrication shop, tell them the sze and material you want the new one in and they can make it for you.

-chet

[Dori Dori]

A larger front sway bar will only make your car understeer more anyway.

Here's my advice...take the money you so egerly want to spend on parts and save it until you have enough for a driving school.

[Nismo_Freak]

A larger front sway bar will only make your car understeer more anyway.

Here's my advice...take the money you so egerly want to spend on parts and save it until you have enough for a driving school.

Not necessarily.

Upgrading the front bar on a stock 240 will make it grip better at the limit. This is because it loses it's contact patch when the suspension compresses 18 ft.

[Exar-Kun]

dude, hes got an altima...-chet

[vq35de]

Another thing I have found driving various altimas at the limit:

Your rear shocks could be going. Not to the point of failing the "bounce test" yet, but have lost some of their effectiveness.

Stock shocks only last 40-50 k at peak effectiveness, much less when lowered or with a speaker box in there all the time.

upgrade to a monotube damper (Koni's et al) or replace your OEM shocks

The back end not pushing up (i.e. soft shocks) can cause an understeer effect in curves. the tires are the single biggest improvement you can make to your car. If you can't afford tires/fluids you shouldn't be driving your car hard.

Oh, and my last set of Seventeen inch tires ran me 1000.00

It sucks and they will only last me 1 year as well

[C-Kwik]

The back end not pushing up (i.e. soft shocks) can cause an understeer effect in curves. the tires are the single biggest improvement you can make to your car. If you can't afford tires/fluids you shouldn't be driving your car hard.

Shocks do very little if anything at all to push up any portion of a car. Springs determine how high the car sits. Spring resiste the effects of the constant load of the vehicle. Shock only resist movement. In other words shocks really only start doing something when the suspension is moving. Gas pressurized shocks tend to push the shaft up when it is out of the car, but the force is quite low. The only reason shocks are pressurized is to decrease cavitation in the fluid as it passes through the shock valving.

Not to say that shock performance is not important, but it's not a result of the shock not pushing up on the car. It's a result of the shock's inability to control suspension movements properly.

As far as making a sway bar, I would look to someone who knows what they are doing. Using the right materials, sizes and equipment can be crucial to good performance. Remember that the sway bar is essentially a spring. There must be a certain amount of elasticity in the material. A brittle alloy could snap under load. Keeping the tolerances acceptable would eb important as well. The end links should be level so that it is not preloading either side when the car is at rest. This can effect the corner weighting of the car and may cause uneven handling in either direction. The bigger sway bar manufacturers use CNC machines. The thickness and length of the bar needs to be controlled to some degree as well. Guessing at the proper overall roll stiffness the bar adds may do more harm than good.

I'd question why your car was responding the way it did as well. Most public roads are not exactly ideal. Especially long banked curves. Race track builders tend to make sure the road stays smooth. Public Roads have little need to support being as smooth for such high speeds. I find it pretty common, especially as roads get older, that they develop undulations. When turning hard, the outer suspension compresses and decompresses over each one and can upset the balance. Tuning for this situation is not easy. Consider that there may be several roads like this and each one may have a varying frequency of undulations. You can try to increase overall roll stiffness and play with shock valving to minimize the time the car feels light as it transitions from a rise to a fall in the road, but ultimately, you will still feel the effect of these undulations to some degree. Also be aware that it's possible that under high load, the suspension may be bottoming out. A sway bar may help if this occurs as it will keep the suspension from compressing as much under load. But before you look for the solution, make sure you know what the problem is.

[carnal_c30]

Bridgestone Potenza RE750 good sticky tires

I heard 730s are better in the dry

both tires have pretty good tread rating

better than my S02 PP at 160 eheh