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tanabe lowering

Discussion in 'Prius c Accessories and Modifications' started by Priusxrs, Sep 4, 2012.

  1. Priusxrs

    Priusxrs Junior Member

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    I see alot of people talking about lowering and the tanabes keep coming up as soon to come. I see them listed now for the C on there web site. Has anyone put these on yet or are they still yet to come? Im really interested in the df210 and tring to fit 17'' in there. They have pics but the C only had 15" on it so it should be interesting just tring to see if anyone did it already to let me know if it would or wouldnt work : )
     
  2. Ryephile

    Ryephile The Technophile

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    Tanabe's lowering springs are available, however the Prius c only has 0.3" of front free compression travel before you start compressing the bump stops. As such, lowering springs aren't a wise decision unless you drive on turn-free glass-smooth roads where suspension articulation is irrelevant.

    17"s are no problem as long as you stay rational with your weight, width, and offset. 205/45-17 is a good tire size that'll fit and is pretty close to stock rolling diameter. Note your rolling resistance will skyrocket and your fuel economy will suffer.
     
  3. DamonBoost

    DamonBoost New Member

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    I just ordered my Tanabe DF210's from importparts.com. Contact Ben there for a great deal. I will be running them with 16x7 Konig Helium and 205/45/16 Tires.
     
    dellrio likes this.
  4. dellrio

    dellrio Im pretty much awesome

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    Let me know how the ride quality is after the install - and pics during install would be awesome as well so we can see the clearance and bump stop issues pointed out above. I do find it hard to believe that any production vehicle has only a third of an inch of free compression as Rye stated above, if that is the case and these drop the car 1.5 inches then you would have no suspension travel at all - and this product would not exist IMO.
     
  5. Ryephile

    Ryephile The Technophile

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    It's not unheard of, though 0.3" is low in my experience. Most front drive mac-strut cars I've measured have <1" of free compression, along with a couple inches of bumpstop compression, however they almost all have tons of droop travel. Having an "active" bumpstop suspension is far more common than most would assume. Keep in mind the bumpstops are soft foam [typically micro-cellular urethane] and compress quite a bit, however in doing so the effective wheel rate skyrockets to infinity. The exact design of the bumpstop determines the effective wheel rate curve, whether it's exponential or linear.

    The problem with increasing the amount of bumpstop-activity from stock is you end up putting lots of shock into the damper body and chassis, and the effective wheel rate is so high it overwhelms the tires, causing snap oversteer, strange mid-corner bump response, and otherwise undesirable handling characteristics. Please don't underestimate the engineering stupidity and good marketing prowess of aftermarket companies. They'll sell you anything you're willing to pay for and put up with. This is why it's important to me to support competent aftermarket companies that have actual engineering ethics.

    Obviously everyone is free to do what they want. I can only hope my insight helps.
     
  6. dellrio

    dellrio Im pretty much awesome

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    I appreciate your knowledge on this topic Rye, but I just need to see it for myself to grasp this. I have a hard time understanding why toyota would engineer a vehicle with such a small amount of free travel ( I am not disagreeing with you - you seem to know what you are talking about ). Also - so you know, it was this issue you raised that prompted me to hold off on any suspension mods until I am more educated on the issue - I by no means am looking for an autocross vehicle, but would like to improve the handling and more importantly (to me) the aesthetics of the car - I hate wheel gaps...

    I have plenty of skill with lowered vehicles, I have personally lowered several of my own, and had the TRD springs on my XB from the factory, but I typically lower cars to eliminate the wheel gaps, and have never really researched into the handling characteristic improvements.
     
  7. Ryephile

    Ryephile The Technophile

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    I understand and commend you wanting to wrap your head around it.

    The reason most OEMs setup the cars to be highly bumpstop active is to do 2 things:
    1.) Use a soft spring rate and offer just barely enough free travel to absorb most protruding road imperfections comfortably
    2.) In corners, get the loaded tires on the bumpstops as quickly as possible to give a planted and sporty feel to the driver. This is intentionally adding NVH to amp up the fun factor by giving the perception of performance.

    So, soft spring rate, and a big squishy bumpstop are essentially a Jekyll & Hyde solution that offers decent ride quality and also confident feeling handling. Note that I said feeling, not necessarily performing. It's many times cheaper than a high-end super digressive damper paired a much stiffer main spring rate.
     
  8. dellrio

    dellrio Im pretty much awesome

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    have you installed your coilovers yet and do you have pics of the ride height after install?
     
    Christophers likes this.
  9. Ryephile

    Ryephile The Technophile

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    Yup it's all right here. I started with Micro Image's ride height recommendation based on their experience with tuning the Yaris platform, so I'm running the car 1 1/8" lower to maintain good roll centers. It doesn't look slammed, but it handles a world better than stock. Even with the stock tires I can take my reference on-ramp several MPH faster.
     
    dellrio likes this.
  10. big pete

    big pete Junior Member

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    Glad to see that springs are finally available. I am going to wait a little longer to see what other manufacturers are going to offer as I don't like that the rear springs have more drop than the front.