Wagging the tail

Maybe the sway bar you don't have.

GM1915 ?

 

Humm...a 2010 Prius with 245,000 miles on the clock going 105 mph is a little loose? My guess...the driver.

Sorry, couldn't resist that one.

 

For a second there, I thought we were back on the COG forum.

I'm just guessing, but would expect the answer to be a combination of factors. One being the lack of sway bar mentioned already, but also weight distribution (about 60-40) along with aerodynamics and other factors I don't know anything about.

 

100-mph speeding tickets soar in California
Hmmm....
Gonna have to start trying to slow down not that the states are starting to miss all of that revenue.....

I haven't noticed any tail wagging on my G3 at speed, and so I'm thinking that they don't actually need a sway bar while on the interstate and driving in a relatively straight line.

Priuses are fairly unsophisticated in the back end because a trailing arm beam axle in the rear is as simple as is gets for a vehicle that doesn't have TONKA stamped on it.


Still....there's other stuff back there that can be worn and set up an oscillation that would grow more pronounced at speed.
TIRES....coil springs, shocks, hubs, etc...

Tires and rims are statistically the most likely source.
Just cause they're at 44 PSI,doesn't mean they're in good shape.

Also the Prius comes stock with itty-bitty tires on itty-bitty wheels.
That's what gives them their characteristic 'dolphin on skates' looks and handling characteristics.

50-series tires suggest the possibility of aftermarket rims and tires and perhaps other non-OEM mods which opens the door wide to some other possibilities......

 

I think that I am seeing the floor through the sway-bar bolt holes in the photo above. So it would be fair to say that Prius rear axle doesn't have a sway bar, as of the moment the photo was taken.

Just because people sometimes like to replace the factory one with a beefier one, doesn't mean there isn't one from the factory....

 

The pictured twist beam also has drum brakes, which means it isn't a Gen 3 assembly. I think it was posted just as an example.

And, the Gen 3 did not have a separate anti-roll bar from the factory. "Separate" because twist beam axles behave like giant anti-roll bars by design; the TRD and Cusco bars increase the roll stiffness by adding an external bar.

 

I did post a G2 rear assy by mistake....not sure if there are many things that are different in the G3 other than the brakes.

I'm still thinking that the sway bar isn't needed on the interstate because any place that you are able to clamp along at 100mph+.....is going to be relatively flat and straight........hardly uncommon in the southernmost Yankee state in the USA.

 

You need side splitters, I have them on mine snail prius and they work wonders at high speeds and cross winds.

 

There are places in the US without actual speed limits.

 

...and interstate freeways are actually designed to safely handle very low volumes of traffic fairly high speeds.
I seem to remember 90mph but do not pretend to have a cite.

PSLs in TX are as high as 85, and there are actually locations where people drive Priuses that have no posted speed limits.

.....the United States isn't the only planet on earth where people drive Priuses......and they actually SELL Priuses in locations where 100mph or higher speed limits are not unheard of.......

 

In case it is an aerodynamic effect, you could try rolling down one or two windows on one side of the car (asymmetrically so not one on each side) to see if that affects the frequency or amplitude of the wagging.

 

You know, you caught me there. I remembered the sway bar in Gen 1 and 2, and I hadn't looked closely enough at my Gen 3 to notice it differed in that respect (even though I've been driving it for 4 years).

Seems like the Gen 1 and 2 'beam' parts were a simpler C-shaped channel (facing aft) with the extra sway bar inside, but the Gen 3 part just has a larger and beefier shape for the beam itself.

 

I've had my G3 over 100 (more than once), and it's been solid. Never had an alignment in the 6+ years now, but never had an incident that called it into question.

 

Not where this life endangering person lives!!!

 

Beat feet nerd, this is why you spent most of your life with you undies wedged up your butt.

 

Apparently you didn't take moderator removing your original message as a clue......

 

Moderator should remove this post for illegal activity. Even when driver pretends not to see speed limit signs, there are always speed limits. None are ever 105 mph.

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