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Testing: Tanabe front sway bar

Discussion in 'Gen III 2010+ Prius Accessories and Modifications' started by HI MPG, Jul 18, 2011.

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  1. HI MPG

    HI MPG Active Member

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    So I was the lucky sap to be picked by Tanabe to test a sway bar for the Prius. I dropped off my Prius in the morning, and they had me out before lunch time. At first I thought it was a test for the rear sway bar, so I kept looking for a rear bar and didn't see the traditional orangish-red trait of a Tanabe. I was a bit mythed since I knew they installed a bar and even left my stock bar in the cargo area. However, as I drove off, I noticed that the handling was definitely a lot sharper and tightly. The car reacted almost immediately to steering inputs, feeling was hyper-sensitive compared to the stock bar.

    I decided to take it out on the freeway to do some higher speed runs and to test steering efforts on some off/on ramps. Holy smokes! Turn-in was so immediate! I was Braille driving on the inside Botts dots, caught out by the sharpness of the steering. I had to correct my steering input to compensate for the improved handling. Wow! Definitely liking the improvements. I took a couple more ramps, this time with full anticipation of the improvements, and wonder if you could make a more direct connection between brain to arms to steering to wheels turning... Once I got comfortable with the improved handling, the steering was so much more precise, and pushing the Prius was actually fun instead of being frustrated at the somewhat sloppy stock handling.

    So I called up a friend with a lift to ask if he could jack up my Prius so I could have a look underneath. 30 minutes later, Prius lifted, I see the telltale Tanabe red in the front! Because of all the plastic shrouding under the car, I couldn't get an access point to measure the thickness of the front sway bar. However, my friend (who has a background in drifting and modding cars) was caught by surprise at how thick the bar is. I took some pictures but couldn't get s good view of the bar installed. Here's a link to the Tanabe site showing the details of the install: Tanabe USA R&D Blog | Toyota Prius (2010)

    The important stuff:
    My contact was with Danh at Tanabe. They run a top notch facility, and Danh was very professional and cordial. Danh showed genuine interest and understanding that some Prius owners want to improve upon the stock handling from the factory. He had mentioned that the aftermarket suspension pieces for the Gen III Prius have been selling a lot better than expected, especially compared to the Gen II Prius. He also said that of all the suspension pieces, the sway bars would make the most difference with improving handling (which I agree).
    Good news is that the installation went well with no complications. I have to bring the car back in a few months to have them check the bushings. When asked, he said he didn't have the exact specs and thickness of the bar, but he'll email me once he receives that info from Tanabe Japan. Also no news on availability and pricing, although I think a decision will be made after the check-up.

    Disclaimer: I also have Tanabe NF210 springs and a strut tower bar installed, so my car's handling was beyond stock sloppy prior to the fitment of the bar. The sway bar improved handling even further.
    3 people like this.
  2. macmaster05

    macmaster05 Senor Member

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    So happy for you Cal!

    You know Dahn?!?! At MoreJapan right?? HAHAHA I was working with him to get my carbon fiber from Japan but it never went through. Tell him Hi for me and I want to buy his suspension stuff for Gen II if he ever gets anything. Or he can test it on my car and I will drive down to SoCal, haha. Dead serious after reading your experience. Anyways, freaking awesome...
  3. 32kcolors

    32kcolors Senior Member

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    I wish a lighter color car would have been used as a test vehicle, instead of Winter Gray Metallic :D

    Nice review, Calvin.
  4. F8L

    F8L Protecting Habitat & AG Lands

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    That is great news!

    After lowering my car i've noticed how unresponsive the car is to initial steering input. I want to install new bars to correct this. Your experience gives me hope. :)

    M, accall them up and be their test car for Genii bars. : p
  5. cyclopathic

    cyclopathic Senior Member

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    Could you post the diameter, if you get it?
    I have Tanabe STB and underbrace and while STB makes pouring oil somewhat awkward, it is a nice looking product which most importantly gets the job done
  6. HI MPG

    HI MPG Active Member

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    LOL. It could have been worse. They could have called the original tester back, so it would have been a black and WGM Prii testing again... or just a black Prius. :rolleyes:



    Thanks Mac. I'll tell him that you are demanding that Tanabe manufacture some Gen II suspension pieces for you to test.



    Same here. I didn't like how the Prius was so resistant to turn-in. There is so much off-center play with the stock set-up that it requires a good amount of pull on the wheel to get the car to turn and then you have to constantly saw at the wheel to keep it tracking smoothly... No mas amigo! Stay tuned for Mac's review of the Gen II sway bars. ;)



    I definitely will provide an update once I get the specs from Tanabe. I also agree with your assessment of the STB. It really tightens the handling

    I'll provide updated feedback once I get some more "seat" time with the front sway bar. A couple of initial impressions now that I've had some time with it:
    1) Steering wheel feels a bit more "weighted." My previous car was a Lexus IS, and the steering weight of the Prius with FSB feels very similar. Just a nice "heft." I don't mean to say that it takes more effort to turn the wheel, the car just feels more substantially planted instead of bouncing all over the place. On the contrary, the Prius now reacts immediately to steering inputs.
    2) Like I previously mentioned, the stock suspension set-up has a lot of play with the steering wheel. It also requires constant minute corrections to keep the car tracking straight, not excessive but enough to the point you have to keep attention. With the FSB, there is practically no play, and the Prius tracks straight. Firmly. Planted. No additional steering efforts.
    3) Mid-turn and lifting off throttle, the FSB helps quickly tuck the nose of the Prius back in line controllably. No drama, no steering corrections needed. The car now provides great feedback as to what is going on underneath it.
    4) Drawbacks? With the STB and FSB, the front end is quite a bit stiffer. This is noticeable under low weight situations, like when the gas tank is near empty. Push the car a bit, hit a mid-corner bump, and the tail end will want to talk with ya. Not that the rear will ever step out on you, but enough to catch you off guard.
  7. xs650

    xs650 Senior Member

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    Hi, Thanks for the report. Since adding front bar stiffness goes against conventional wisdom on an under-steering front wheel drive car, here's something from an SCCA forum that explains why it works.
    Big Front sway bar on a FWD car? - Technical Forum
    The question that started the thread was about a car that had a better front suspension than a Prius, but McStrut (McPherson strut) front suspensions are covered in the discussion.

    Will you get the chance to push it to the limit on some nice safe place? It would also be nice to learn what lifting the throttle does to handling at the cornering limit.

    Your item 4 is encouraging. If bumps are causing the rear more effect than the front it's a good indication that you haven't added too much front bar for real world less than perfect roads. Any more observations on how it handles rough surfaces in corners would be appreciated. By "poor" I mean typical poorly maintained roads, not potholes and tank traps. Twisty roads that you would still want to drive quickly on but not race track smooth.
  8. V8Cobrakid

    V8Cobrakid Green Handyman

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    how do you guys get these testing position.. i but everyone i can to get test stuff... i was one of the original testers for Brian at BT tech for parts (cool guy)

    not to sidestep.. but i'm always looking for test on the genII.. and i live in los angeles... i push the car the hardest out of anyone i know. i also tow with it...

    i'll eventually buy all these parts when i get a job again... but then i tend to not really share my views as much.
  9. 32kcolors

    32kcolors Senior Member

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    Paying close attention to this forum helps :)
  10. HI MPG

    HI MPG Active Member

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    Well, I'll see if I can find a empty parking lot somewhere and see if I could do my best impersonation of Paul Walker in Fast & Furiouos. :) The FSB does keep the Prius fairly stable at the limits but of course I would like to conduct more testing in a controlled environment.
    As for less than perfect roads, not too many I could think of in SoCal unless I want to go into the 'hoods. There's a pass through a canyon I used to take to my old job many a years ago (like 6) which I wouldnt mind testing out. But it gets fairly crowded on the weekend. Theres always Ortega Hghwy but it's a traffic and police trap on the weekends. If I find any and conditions are right, you know I'll try. ;)
  11. xs650

    xs650 Senior Member

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    Thanks Hi,

    Just remember to keep the rubber side down and the shiny side up.

    XS
  12. cyclopathic

    cyclopathic Senior Member

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    What pressure do you run front/rear?

    Mine had similar issues with rear TRD swaybar and Tanabe STB upfront. I had gone from 42psi front/40psi rear to 42/38, and it cured both of the issues. Stability in crosswinds (or trackability if you want), and tail loosing grip on mid-corner bump.

    Also seems to be more appropriate at static load; front and rear tires deflect more similarly when parked on 100% flat concrete.
  13. cyclopathic

    cyclopathic Senior Member

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    Thnx for the link. Still not decided if and what I wanna do with mine. Better shocks probably, but not for $1200 :mad:



    Also what size/type rubber do you have on? How does it respond to mid-corner acceleration/brake input under the limit?

    Not to derail but would be interesting to compare it to OEM front/TRD rear set up. Mine suffers from lack of grip on 15" LRR tires. It looses grip quickly esp through the bumps but feels almost like a rally car: while drifting at all 4-corners you can make it rotate in turn by gently applying accelerator.
  14. HI MPG

    HI MPG Active Member

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    Excellent advice... and something I plan to follow to the T.



    I remember it to be 40psi front and rear. I'm still trying to find that delicate balance between economy and sport with these tires. Thanks for the advice on the tire pressure. I am have to test it for stability.

    With your current setup, do you experience any bit of understeer? I was talking to Danh at Tanabe, who informed me that a bigger RSB would tend to cause the car to understeer more...




    I'm running 205/55 16s, Continental ContiProContact. They are LRR tires but provide plenty of grip. Mid-corner, under hard acceleration, the tires just grip and rotates the rear-end very nicely. I haven't pushed it beyond what is controllable on the streets, but I can say that the limit on these tires are very high.

    Similarly, trail braking around a corner is very controllable, although IMO, it could use a bit more grip. I think this is just a side effect of LRR tires. Through bumps mid corner, they still hold their own.

    The 15 LRRs do slide very easily. When I was running with the stock Yoko 15s and had to brake hard and turn at the same time, I would also encounter that 4 wheel drift you are talking about. I know the Prius has anti-lock brakes, but my brakes actually locked up, forcing the Prius in a bit of a slide momentarily. Haven't had this issue with the 16's (nor the non LRR 17s which I ran for a bit), so my opinion is that the stock 15 LRRs don't provide enough grip under hard corner braking (or at the limit cornering).
  15. GloryThief

    GloryThief Junior Member

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    nice review! nothing for the second gen :/
  16. HI MPG

    HI MPG Active Member

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    Okay, so Danh from Tanabe just contacted me to advise that Tanabe just released specs of the front sway bar: 25.4mm in diameter. The FSB is on their website yet but still not available for purchase. Here's the link:
    Tanabe USA Inc. - Sustec Stabilizer

    Further feedback now that I've had additional seat time with the FSB: With the bar, the Prius just grips like a man hanging off a 20 story building.... Yeah, you know he'll eventually lose grip but while he's hanging on, he's gripping the edge for dear life. The FSB bumps the upper limits of handling and provides very direct, precise response. For those looking to improve and enhance the handling of their Prius, I would HIGHLY recommend this FSB. In fact, I'm surprised Toyota didn't develop one for their PLUS package.
  17. 32kcolors

    32kcolors Senior Member

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    Now time to shell out more of your hard-earned money for the RSB so you can continue to harass the MB and Porsche Cayennes around the Newport area twisties and give them a nice view of your Valenti lights :thumb:
    1 person likes this.
  18. HI MPG

    HI MPG Active Member

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    :) LOL. Tempting. I already do that now... too bad I eat dust when the road straightens out.
  19. xs650

    xs650 Senior Member

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    The diameter is interesting. 25.4mm = 1.00 inch. Strange that Tanabe would use that diameter unless the bar is made in the US where that is a standard, widely stocked bar and tube diameter. I doubt that it is a standard size in Japan.
  20. Dark_matter_doesn't

    Dark_matter_doesn't Prius Tinkerer

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    I just ordered this from JuicedHybrid for $215, and I'll probably have it in a week or so. I'll take pictures during the install & post the process. The install looks a bit trickier than the rear anti-sway bar.
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