Rear Sway Bar

I just placed my order for the Progress sway bar at THMotorsports!! You guys sold me. Actually, I did more research on "Progress vs TRD" for Corollas and there is a lot of information out there. It seems that among tuners, TRD is kind of a rip-off. Also, TRD sway bars have been known to snap.

I was initially hesitant to go with Progress because I had not read a lot about them on this forum, but apparently Progress is a very reputable brand. So in the end my decision was easy. Shame on me for ever considering the overpriced TRD.

I got also got 4% off using a coupon I found online, so my total came to $107.52!

Now, I did have to lie to THM when they asked "What vehicle is this part for." I was afraid they wouldn't give it to me if I wrote "Prius," so I entered "Toyota Corolla" like a good boy. LOL.

 

24mm != 24mm all the time, though. Is the bar solid, or hollow? If hollow, *how* hollow (wall thickness)? etc, etc. All do not act the same.

That being said, feedback from buyers is often the best way to decide. Which this thread obviously helps with.

I may scrape together the money for the Touring rear bar some day. If I ever upgrade, I can always toss the Touring on the 04.

 

Ah the man behind vfaqs. Thanks.

Based on my research, the Progress bar is solid. The Touring bar is hollow. But I'm still unsure about what difference it really makes - some people say that a hollow bar is less resistant to bending for whatever reason, but most people say that a hollow bar just saves the manufacturer the cost of materials.

I will have a Touring bar for sale once I get the Progress installed.

 

i'm also looking to upgrade my rear sway bar and possibly the front as well. i'm leaning towards Progress too. however, shipping to australia will add to the cost. THM's site suggests to use the Bongo service for international shipping which the site says it will save cost. Is there any truth to that?

I don't know if you guys are aware also of UltraRacing products of Malaysia. Looks like they have some interesting stuff as well. If you go to their website (ultraracing.my) and do a product search for a Toyota Altis (2002) or a Toyota Wish (2005), product UR-RT20-216 (20mm) rear sway bar (they call it torsion bar) looks like it would fit. they also have a different stabilizer bar that sits just below the sway bar (UR-AR19-076) which does look like it could get the job done just by itself.

I've asked them if it would fit the prius and they said that they'd have to try it out first on the car itself before they could confirm if it fits. i've asked for the dimensions of the sway bar and they sent me a photo of UR-RT20-216 with the measurements. can someone confirm if these are indeed the measurements of the prius rear sway bars?

 

For a given torsional stiffness, a hollow bar casts a bit more to make and weighs less.

The outer part of the bar provides most of the twisting resistance because the twisting resistance of a solid bar is proportional to the diameter to the 4th power. A small increase in outside diameter lets you make the bar hollow and have the same stiffness as a solid bar with less weight for the hollow bar.

 

You can substitute the rear Corolla bar for the Touring bar. It is similar in size and I bet you can find them cheaper and easier at a salvage yard.

Or you can buy Mac's bar. He is so impressionable when it comes to mods. Someday I'll get him into a set of projector headlights. lol

 

Lol maybe. One thing at a time. My best friend in Davis just bought a set of morimoto mini's for his Biemmer and occasionally comes to me for advice, which actually comes through F8L. Lol. We thought we were done w/ mods but the bug bit us both this month! Must be the holiday season approaching.

 

It's difficult to see where they are referencing the measurements from your picture. For my old prius rear sway bar:

Hole center to hole center 101.6 cm
Outer diameter of bolt fitting: 2.54 cm
Inner diameter of bolt fitting: 1.65 cm
Height of bolt fitting: 4.95 cm
length to first bend (not including bolt fitting): 30.5 cm (roughly)
Length of center section: 40.6 cm (roughly)

The single decimal place measurements are rough measurements, with a tape measure. The two decimal place measurements were measured with a caliper. Both in inches, converted to cm, 1in. = 2.54cm.

The bolt hole on the prius bar has a lot of slop in it, maybe 1mm all around the bolt. On the progress bar, there is not as much slop - maybe 0.5 mm all around.

I hope that helps.

 

thanks, NeoPrius for taking the measurements. looks like the measurements are pretty close to each other except for the total length (end-to-end). i was leaning on the Progress bar too but it looks like THM can't ship that long of an item and would cost a lot. I guess i'm off to salvage yards then and look for a stock corolla one.

 

Yep, and a good post with example is here. The main advantage is weight, but for the really rough-driving crowd, the advantage is a much larger diameter bar can be used for the same weight as a smaller bar, giving greater stiffness. Mostly unnecessary on a Prius, you don't want it too tail happy.

Yeah, I might hit one of the few pick-your-part yards in my area to see about a Corolla bar. Maybe I can get one for less than a Jackson. It would require reconstructing my portable tool bag, though, haven't needed it for years (since getting the 04 in late 03, basically).

 

Are you implying that a 24mm hollow bar is actually not 24mm in total physical thickness? IOW, it is thicker in diameter than a 24mm solid bar because the diameter is measured by the hollow space? If so, how (extra) thick are we talking? I'll measure my "20mm" hollow Touring bar when I take it off but I find this extremely hard to believe.

Edit: Ok I found something on the internet and I read this at least 10 times:

The end gets confusing. Why does 30mm hollow = 24 solid? I thought he explained that 27mm hollow = 24 mm solid.

If he's right, all this would mean that a 24mm hollow is not as strong as 24 mm solid, even if 24mm was measured from the inner diameter, because a 3mm thickness in the hollow bar (for total of 27mm) is still not 30mm.

 

Seems like the discussion about hollow vs. solid vs. diameter is pretty much academic, since there aren't a whole lot of choices out there that fit the Prius.

We're pretty much limited to what's available out there unless someone has the resources to make their own bar. The 24mm Progress bar is a few pounds heavier in weight than the stock prius bar, but it's sort of a moot point since these are commuter cars.

 

Yes, it's academic but the reason I'm asking is because I'd like to know how much of an improvement (quantitatively) my new bar will be.

My main question is basically, what does a hollow 20mm bar mean? Is that 20mm inner diameter or 20mm outer diameter? Obviously it makes a huge difference.

Our Progress bars will have a stifness of: 331,776 SF (24mm^4)

My Touring bar (if calculated w/ an inner diameter of 20mm and assuming a 1.5mm wall thickness x2 for a total of 23mm) will have a stiffness of: 279,841 (OD) - 160,000 (ID) = 119,841 SF

My Touring bar (if calculated w/ an outer diameter of 20mm, same wall thickness) will have a stiffness of: 76,479 SF

That's a 176% increase vs. 334% increase, depending on how they name it.

 

Mac, speced A/R or swaybar diameter is always the outside diameter.

But...hollow bar wall thickness can vary a lot. Guessing at wall thickness can get you big errors. If you can get an actual wall thickness measurement you will be a lot better off.

 

Is there a salvage yard with Prii in our area that you recommend?

 

OK, let's throw a massive wrench into the situation - the rear beam axle isn't exactly stiff, considering it is a C-channel. I wonder how much more stiffness you could add by either partially or totally boxing it with welded plate? You wouldn't ever be able to get the swaybar out again, but boxing suspension arms is common in rally and other racing for strength, but for our wimpy beam axle, I wonder how much it would help, if any?

Of course the real test would be to get a spare beam, cut out as much of the center as possible, and then weld in a square tube. Then run ABA tests. No sway bar at all in this case, unless you mounted it in the square tube before welding it up into the suspension.

A removable solution would be to weld long strips of 0.125-0.25" steel to the top and bottom of the beam opening (weld nuts to the back side of the strips first), then bolt a plate across the entire beam using crazy high torque values. Or better yet, build a C-section with short arms that slips inside the stock C-channel, with captive nuts on it, then drill holes in the stock beam to bolt it in place. That would require the least mods to the stock beam, and might be possible to do with the axle in place.

Not that I have the time or money to do so, but thought I would throw that out there. We haven't had enough discussion in this thread

 

Boxing the channel or replacing it with a square beam would make the axle way stiffer than anyone would want.

Adding strips would work, as would this bolt in sway bar arrangement.
http://www.houseofthud.com/rintintin/shinebar.jpg

The GenIII rear axle is a closed section round tube with a big dent whomped into it to reduce stiffness. Toyota could easily make it stiffer than anyone would want by just not forming as deep a dent.

 

I went through all of the yards on recycle road and no one had any Prius parts.

 

I fail!!!!!!!!!

So I had my car lifted, all tools laid out, ready to install this bar. I went under the car but I couldn't loosen any of the 4 19mm bolts for the life of me. They were way too tight. I tested the ratchet wrench in different directions in case I was turning it wrong, but I'm pretty sure I had it right anyway (lefty loosy). I even added a metal pipe for more leverage but guess what, that snapped my socket wrench into 2 pieces.

I am so sad now that I have given up and returned everybody's tools. It's back to square one. I think I'm going to have to go to the professionals. I called back my suspension guy and explained everything but he still charges $40 minimum visit, but that's whether he can loosen the bolt or not. He suggested torching the bolt or using an air ratchet but I don't have those tools. I have an appointment with him tomorrow morning.

1) How much should it cost for a mechanic to install the rear sway bar? I'd like to know if $40+ is too high.
2) Would anybody actually like to help me instead? I know its a long shot but FYI - I live in the South Bay (Nor Cal). I can lift the car w/ my tools but you can loosen/tighten the bolt (I don't want to be personally responsible for breaking any more tools). I'll buy you dinner or something.

Not only is my ego shot but I am minus a ratchet and likely going to have to pay someone to do this install.

 

sh&% happens bru. Cheap tools break pretty easy when you go gorilla style with them.

If you cannot get help then $40 is not a bad price to install the piece. Most shops would charge you their hourly rate which is closer to $80-100/hr. By the time the mechanic talks to you, pulls the car into the shop, installs the piece, bills you out and get back on another job they will have likely spent an hour on the project. So IMO $40 is not bad.

I'd offer to do it for you but I don't have a jack at my house and you'd spend half your money on gas to get up here. lol