Sway Bars Installed.

Thanks for the review! How much bigger was this sway from from the stock bar?
This is definitely my next mod!

 

After my rear sway bar install, I also noticed flexing and twisting. Front struct bar did not help that, but did increase steering response and rigidity in the front. I think the next mod for sway bar upgraders are 4 pt cusco lower bars.

For your rear sway, you installed the bolts and nuts exactly like stock correct? People on the xB forums have reported the bolts and nuts loosening when not installed correctly, then leading to sway bars falling to the floor. Sounds silly, but its happened before.

 

I installed these bars also! The car handles like a dream now, I also have the Tanabe Strut tower brace.

Unfortunately there is now something wrong with the suspension....
At low speeds on rough surfaces I can hear and feel a metal on metal "clunk" sound from the front suspension. I verified 2x that all the bolts that I touched were tightened and verified that the sway bar bushings were sitting properly.

I am wondering if I damaged the Strut Mount or maybe an end link.

Got an appointment with Toyota Monday, I'll keep you all posted.

 

These bars from Hotkiss sound very,very big for the Prius (32mm front, 25mm rear). After many anti roll bar installations I can say that bigger isn't always better. An example was a modfied MR-S were we installed larger bars. The result was too much connection from left to right and clunking sound. It felt great but the car was overreacting at some point.We went then to Whiteline (Aussie product, unfortunately they do rust too quick) what came in smaller diameter. These made the job and provided less body roll with a good feedback before the car starts to oversteer. IMHO Hotchkis stuff is good stuff for my Camaro Z28 but too big for cars like Prius. Also I wouldn't be surprised if the clunking noise comes for the larger diameter in teh front and it's way it is mounted. It can get even worser when the gar is getting lowered. Other bars like the Cusco are 25mm in the front and I'm sure that'll should be enough for this type of car.

This is a good article I just found:

Going Too far?

Most manufacturers of front-wheel drive cars keep the rear roll stiffness fairly soft. But if stiff rear sway bars are good for handling, why do they do this?
Too stiff a rear bar in a front-wheel drive will result in a much higher likelihood of a spin if you lift-off mid-corner. A soft rear bar also results in plenty of understeer – something which is good for safety in the averagely-driven commuter car. However, if you don’t go to extremes, it’s quite possible to gain better turn-in and much improved mid-corner balance with a bigger rear bar. (Or the installation of one where none previously existed!) You’ll also find that the car can be much better throttle-steered – back-off the throttle a little and the rear will come out gradually; get back on the power and the car will follow the cornering line.
The acid test is cornering on a wet road with a load in the back – you don’t want the rear so stiff that a slight throttle lift will cause the car to spin. But to get this effect in an otherwise standard car, you usually have to make a radical difference to rear sway bar size.
Note that a front-wheel drive with an over-stiff rear sway bar (or more correctly, too high a total rear roll stiffness) will feel great up to 8/10ths – turn-in will be sharp and the car will sit flat. But go that extra step and you can be bitten. In standard cars we’ve only ever experienced this once – but that car could spin literally in its own length.... see the end of New Car Test - Piloting the 1999 Hyundai FX Coupe.
We don’t want to frighten you – make the modification with common sense and you’ve nothing to worry about. But there is a reason that 99 per cent of manufacturers don’t go over-stiff with the rear... and it’s something you should know about.

 

What is the stock front bar diameter again? There is no rear bar correct?

tnx,
Mike

 

Robby3, it's good to hear from someone with an understanding of the effects of roll stiffness on handling.

The problem is that slapping on some big fat anti-roll (sway) bars makes the handling feel better and the steering quicker at low to moderate cornering loads, but when you over-cook it in a corner, or have to back off the throttle in a corner, it can bite you in the rear end. It also screws up handling on bumpy roads.

The factory leave some room for improvement, but not a gross amount.

 

front is 24mm, solid? the replacements Hotchkiss, TRD are tubular.

I have TRD rear (22.6mm) designed to work with stock front, and IMHO there isn't any need to go any bigger. On stock size LRR tires you will not see any benefits. As is there is no body roll going through corner, and you can make it drift on all wheels. Front still looses grip first, pretty safe.

 

That is good to hear on not needing a different front bar. Saves some bucks that way

Mike

 

AFAIK the stock front one ist 24mm tubular, not solid. And of course, there is no rear stock one xs650 says it 100% correct (sorry, english is not my first language).

Ans yes, I'd like to have more response in the steering too as well as more of a "flat" feeling. I therefore go the chassis route first and will stiffen it with Cusco parts (I'm a dealer in Switzerland for HKS, Cusco, etc.) step by step. I may even add a rear sway bar to see if the wheels keep in touch with the road longer. But I'm not sure if I'm really gonna touch the front one. The wheel base (side-to-side) is not that much on the Prius and probably a 26mm solid design will be enough.

BTW, there are different solutions for the rear. This Hotchkis is direclty attached to the shock bolts (hopefully the bolts is long enough) and therefore acts as a stabilizer bar. Also the Cusco version that bolts to the shock braket is a pure stabilizer bar. But all bars are the same, stabilizer, sway bar, anti-roll bar. The TRD comes with end-links. This kind of sway bars transfers the force not directly but through endlinks that often allow some adjustment.

 

I just installed Tanabe STB earlier today (ordered TRD bar, Tanabe STB and under brace). Drove ~100mi some on twisty country roads, some freeway, exits and downtown, empty and with 5 people/load on board. Coming through 270degree 2-lane exit passed Camry and got passed by latest Mustang GT as a point of reference.

While there is improvement over just rear stabilizer, it is much smaller then rear bar was and less obvious. STB seems to make front hook slightly better, less front sliding (not that was much to start with) and slightly lighter/more precise steering. Probably better front tire wear.

It is probably "the law of diminishing effect", looks like when underbrace goes in it will do nothing.

I bought Prius for MPG and utility, if wanted sport car handling had gotten Miata. Not trying to turn it into race car, so will not trade LRR tires for stickier ones.

IMHO if you just wanna fix excessive body roll and on budget TRD sway-bar (or if you can locate Eibach) is way to go good luck

 

IMHO start with rear sway bar. With 22.6mm TRD rear there is alot less body flex then there was without it. Looks like there was a huge mismatch btw front and rear axles and it was causing excessive body flex. With rear stabilizer front is still stiffer, I ran one side over speed bump to test and rear is more compliant then front.

 

What's your thoughts on running the TRD rear bar, tower braces and chassis braces, and Tanabe DF210 springs? Or NF210 springs? I am thinking of autocrossing my Five next season after I buy it and set it up properly of course It will have to get autocross tires on aftermarket 17's as I would leave the LRR factory tires on the factory 17's for street use.

tnx,
Mike

 

This stuff is difficult to judge by seat of the a pants feel, but the stiffer your suspension the more chassis structural stiffness matters. The underbrace will make more difference now than it would have without the bar. Whether you can feel it seat of the pants is another issue.

When you add rear roll stiffness, the rear bar is trying to keep both ends of the the car level and putting a bigger twisting moment into the car's structure than if you didn't have the bar.

You should also do yourself a favor and find a place you can safely push the car beyond it's limits and see how it responds. A big empty paking lot, autocross course, empty road with a nice safe are to spin into....

The cars reaction to being pushed well beyond it's limits in a corner may be completely different that what you notice in mildly brisk cornering.

 

Not sure, I get my kicks riding motorcycle through mountains.

I would probably start with rear stabilizer and then tires, and then do the braces as needed. Tanabe STB and under-brace were 195$+20$ shipping from jdmengineimports, the cheapest price on Cusco rear brace was as much.

I suspect that with lower springs front under-brace will be felt on every speed bump but you could probably only put it when you get ready for cross. Cusco 4-point should be tacked in pretty good. Also Prius as is low enough, if lowered would it create problems in daily use? Are there any better shocks available?

here are links on discussions:

http://priuschat.com/forums/gen-iii...3436-does-prius-iii-has-anti-roll-bars-2.html
http://priuschat.com/forums/gen-iii-2010-prius-main-forum/74666-undercarriage-photo.html
http://priuschat.com/forums/gen-iii...sco-center-power-brace-installed-finally.html

and part #s:
EIB-8290-312: Eibach Anti Roll Kit (discontinued) ~150-160$ shipped
TRD PTR11-52091 ~240$ (with links ordered from trdsparks)
TRD PTR11-52080 ~150$ (w/o links discontinued due to breakage but may still be available)
TRD PTR11-52090 ??$ (listed as replacement for PTR11-52080)

TNB-TTB153F Tanabe STB for the 2010 Prius for $107
TNB-TUB153F Tanabe 2-pt underbrace $88.25


Good luck

PS. Also my Prius doesn't have enough grip to find out if Hotchkiss set up would be better for autocross then TRD setup. Then stiffer/lower springs help to control body roll, it would be difficult to say what is better Tanabe DF210/Hotchkiss or Tanabe DF210/TRD?

Check Eibach lists springs for Prius, part # 82100.140

 

From what I read with McPherson suspension all the load goes into upper strut mounting point, so STB will matter more, and lower brace less (if any) then on double wishbone.

Usually you find all kinds of problems with chassis with stickier rubber, I strongly suspect that with 15" Michelin Energy Saver A/S at 42/39psi I will never find out if it makes any difference at all

And I am not planning to take prius (or any car in general) to Deals Gap, have bike for it :cheer2:

IMHO in OEM trim due to disbalance front bar was trying to keep rear leveled and was twisting body. With rear stabilizer supporting rear some, there is less twisting forces fore-aft. Front is still stiffer, at least per one side on speed bump test.

 

My one chance to do Deals Gap I was in a rental Oldsmobile Alero and I got stuck behind a group of Goldwings with no safe way to pass them on that road in a car. They were sloooow.