Taming the ride quality on the ST...

Discussion in 'Fiesta ST Chassis Upgrades' started by Joe Schmoe, Jul 14, 2014.

  1. BostonDriver

    BostonDriver Member

    When I first got my Fist I was a little disappointed with the ride on the roads around Boston, but figured that was the cost of having such a fun and good handling car. I was very happy to feel the ride after installing my new wheels and tires though! It's amazing how much of a difference it was losing almost 8.5lbs of rotating weight from each corner. I've always been a big believer of going lighter before getting more power. First and easiest place is at the wheels since rotating mass has an effect 4 times that of static mass. That plus the fact that Potenza's have always been known to have great turn in characteristics at the expense of ride quality, which is why I never liked them for everyday street tires. Bottom line is that everyone jumps to do something to their suspension to fix ride, when in most cases they end up lowering it which will negatively effect the handling unless properly setup (corner balanced, corrected for roll center changes). Instead why not get some good wheels that'll help the ride, retain the already very good handling characteristics and increase performance when accelerating/decelerating and turning...?

    New Wheels vs. Stock = 8.3lbs lighter per wheel.

    17x7.5 OZ Ultrlaleggerra's (15.7lbs each)
    215/40x17 Pirelli P Zero Nero's (21lbs each)
    Total wheel weight of 36.7lbs

    Stock wheels (26lbs each)
    Bridgestone Potenza RE050A (19lbs each)
    Total wheel weight of 45lbs
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  3. EcoBeast

    EcoBeast Member

    Boston Driver, that is definitely another option. $1200 on wheels/tires is more attractive, literally, than $1200 on coilovers. Although I had read in a another forum here that the Ultraleggerras might be a bit prone to the bending at the rim if you hit a pothole due to their lightweight construction - any issues?

    On a related matter, my car was delivered with tire pressure of 43 psi (measured cold) all around! It took me a few weeks until I though of checking it and brought it down to 39/36 psi. It actually seemed to help the bounciness a little bit. It might be a good idea for the new owners to check their tires right after delivery.
    Last edited: Jul 20, 2014
  4. BlueBomber

    BlueBomber Active Member

    Hey there, I had the same problem as you with the ride quality.
    The problem is your tires.
    I plus-sized my tires to 215-45-17, speedo is slightly off but the car rides SO much better, handling feels unchanged.
    Otherwise the car is on stock shocks at stock ride height.
  5. EcoBeast

    EcoBeast Member

    BlueBomber, that's an interesting option as well. I have to get a set of snow tires and steel wheels eventually - I'll look into that size.

    Any issues with tires rubbing in the wheel wells? What tire brand did you go with?
  6. BlueBomber

    BlueBomber Active Member

    No rub issues.

    I went with Hankook Ventus Concepts I think cos I get a fatter discount on those.

    Perfectly happy with them.
  7. timo

    timo New Member

    If you pick new dampers with less rebound damping than stock, be very careful (if you aren't already) about hitting potholes.
  8. BlueBomber

    BlueBomber Active Member

    that's a great point and why I left the shocks alone and opted for different tires instead.
    Short answer: Different tires will improve your ride quality, but be careful with what you choose, simply remaining the same size but with a different brand tire will probably help too.
  9. David Heavey

    David Heavey New Member

    My solution to the hard rear suspension ride was as follows:

    This is the solution to the extreme impacts that you experience with the standard dampers at the rear of the ST. For me the front is fine and rides speed humps with aplomb.

    With the rear Koni Sports at their softest setting the situation is near perfect, the car rides well my back ache is cured. long trips over uneven roads are now fine.

    I think that the Konis could be set a bit harder with some experimentation but that is in the future

    I originally fitted the Koni's thinking they where set fully soft, when in fact they where one turn up and while that was better, it was fairly similar to the standard.

    I reset them to full soft and the car is transformed. I gave it a good run over the Welsh hills for 240 miles and had no complaints. Do bare in mine that is a short wheel base shopping car with an uprated twist beam rear suspension and the ride will never be Rolls Royce.

    One bit of confusion is that Koni only list the Sports for Fiesta cars to 2012 pre-facelift (mine is a 2015/2016 but they are in fact a perfect fit. I believe the issue of date is with the fronts and to do with the bracketry that is fitted not the dampers themselves.

    I now have a quick touring car that still makes me smile, and rides the bumpy British roads.

    The handling changes a bit as the rear tyres now ride the changing surfaces better and grip is better, and therefore lift off overstear happens later and at higher speeds, but it did tend to let go early anyway so that is a plus. It is just a bit harder to hang the backend out around roundabouts, assuming that is your thing

    I paid £110-00 each for the rears inc shipping and life time warranty, and I am 100% happy with the results

    I have also read that the Koni Str-T are similar to the softest setting of the Sport but have no personal experience of these. They could be a cheaper solution.

    Hope this all helps

  10. hyatt

    hyatt Active Member

    I need to do something about the shocks/springs on my 14 FiST but I did notice a marked improvement in ride quality when I got rid of my RE050s and replaced them with a 205/45/17 Michelin Pilot Super Sport. The Super Sports are quieter, ride better, have a much longer practical lifespan and in my canyon driving experiences, I've noticed no real decrease in practical grip levels. That said, I haven't taken it to the track since putting the Michelins on, but I wouldn't expect a huge difference there.
    David Heavey likes this.
  11. David Heavey

    David Heavey New Member

  12. David Heavey

    David Heavey New Member

    I picked this up on the Fiesta ST Owners club forum,courtesy of David George.

    I do not know what is happening to Mexican built ST's but this is the situation with German build cars

    "The article linked to below might explain why some owners of the ST feel the rear is too stiff (Bouncy) and others don't.


    Turns out all ST builds from summer 2015 got revised rear suspension settings with softer springs / dampers but a stiffer twist beam, also tweaked front suspension and steering settings, all as per the set up the ST200 gets."

    My car was a September 2015 built car said to be the 2016 specification and it makes sense..

    I hope this does not add to the confusion.

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