Rear Koni Shocks: Install

[Flaco]

For those interested in a smoother ride and don't have the coin for the yellows, I recommend the stock front struts with Koni STR.T (orange) shocks on the rear. I installed them a couple of weeks ago and it has dramatically softened up the ride while still maintaining a sporty feel. I have had them on with Vogtland and stock springs and they both ride a lot smoother than with the stock shocks. The jostling I got when driving on the freeway has almost vanished completely and the car stays in the lane with greater ease. I can still hear a noise when driving over road joints (factory tires and wheels), but the noise is no longer accompanied by a jolt. They are currently on sale at Tire Rack http://www.tirerack.com/suspension/suspension.jsp?make=Koni&model=STR.T+Street+Strut&group=STR.T+Street+Strut&partNum=8050-1130&autoMake=Ford&autoModel=Fiesta+ST&autoYear=2015&autoModClar= Please let me know if you have any questions or concerns.

I just did this swap after having the Koni Yellows on my previous 2014 FiST . Prefer the Koni Orange for daily commute !

 

[blue2turbo]

I did the same and ran Koni STR.T rears with stock fronts and Mountune springs and I think the rears helped settle the ride out a good bit, I like the way the car drives all around now.

 

[Reaper]

Just did a rear Sport install and only have a couple additions for this thread. The bolt heads for the upper mount are 10mm. I found them a bit hard to get to until I removed the wheel, pulled the flexible liner outward and now had easy access to that top area. Everything else was just as reported except on mine the lower bolt with 15mm head has a nylon threadlocker just like the uppers. I expect we're supposed to use new bolts, but who does that?

I set mine to 3/4 hard (1/2 turn off full tight) for autoX. It will probably just start an argument, but you're never supposed to adjust a shock full hard. Some shocks lock up, more commonly most shocks become non-linear at the last bit of adjustment and you can get weird results. You can get this from Koni, or from shock tuners who use shock dynos. I backed off 1/2 turn. I'd probably feel comfortable reducing it to 1/4 turn if necessary.

 

[M-Sport fan]

^^How many turns from full loose to full tight on rebound for these.

I am used to using the slotted knob they give you with the rear single adjustable dampers for the f bodies, and with the triangle/arrow they put on it, it is easy to tell how far you adjusted it for rebound.

 

[Cligedy]

2 full turns. A quarter turn makes a meaningful adjustment.

 

[M-Sport fan]

2 full turns. A quarter turn makes a meaningful adjustment.

THANKS!

 

[M-Sport fan]

Do you have to get an alignment after changing out the rears? I suppose you do have to get an alignment if you change the front? Great write up! I will be using this as a guide when I change out mine for sure!

Unless you shim, or cut and weld the rear axle hub mounting plates, we cannot change the rear alignment settings on these cars.

But changing the rear dampers and springs on these cars would not have any effect on the alignment anyway, due to the solid/beam axle.

The exception is IF you 'slam' it downwards over 1.5" to 2" with insane lowering springs, or 'bags', the geometry would be all off, and totally messed up, for good handling/ideal instant center location/etc.

 

[zohaib]

Unless you shim, or cut and weld the rear axle hub mounting plates, we cannot change the rear alignment settings on these cars.

But changing the rear dampers and springs on these cars would not have any effect on the alignment anyway, due to the solid/beam axle.

The exception is IF you 'slam' it downwards over 1.5" to 2" with insane lowering springs, or 'bags', the geometry would be all off, and totally messed up, for good handling/ideal instant center location/etc.

I wouldn't expect anyone bagging a car to know or care about suspension geometry

 

[M-Sport fan]

I wouldn't expect anyone bagging a car to know or care about suspension geometry

Very true, but some on here do just that, and hopefully they realize it is ONLY for 'looks'/shows.

 

[Stormy]

I put rears in a couple weeks ago, 1/4 turn off full hard. They didn't do anything to improve the daily ride, that's for sure. Oscillations over bridge seams and slab pavement are even more bouncy now. I haven't had it to the track yet to really put them to the test and I don't drive crazy enough on public streets to have noticed a difference in cornering but I'll hopefully have some constructive handling feedback soon.

 

[M-Sport fan]

I put rears in a couple weeks ago, 1/4 turn off full hard. They didn't do anything to improve the daily ride, that's for sure. Oscillations over bridge seams and slab pavement are even more bouncy now. I haven't had it to the track yet to really put them to the test and I don't drive crazy enough on public streets to have noticed a difference in cornering but I'll hopefully have some constructive handling feedback soon.

Still on factory springs, correct?

 

[Stormy]

Still on factory springs, correct?

Yessir.

 

[Reaper]

I put rears in a couple weeks ago, 1/4 turn off full hard. They didn't do anything to improve the daily ride, that's for sure. Oscillations over bridge seams and slab pavement are even more bouncy now. I haven't had it to the track yet to really put them to the test and I don't drive crazy enough on public streets to have noticed a difference in cornering but I'll hopefully have some constructive handling feedback soon.

Same here. At 3/4 hard, the ride has degraded, but I still don't get significant autoX rotation. I'm of the opinion that to make us happy, we need to have shocks that are easy to adjust hard at the event, and back them off for street. I don't recommend these Konis except where you want no-compromise performance and either trailer the car or are willing to put up with a kart-like ride. I suppose some of the coil-overs might be better, but I'm an H-Street'er.

BTW, some of the FiST guys I run against get plenty of rotation. Must be driving style. But we actually turn identical times.

 

[Stormy]

Same here. At 3/4 hard, the ride has degraded, but I still don't get significant autoX rotation. I'm of the opinion that to make us happy, we need to have shocks that are easy to adjust hard at the event, and back them off for street. I don't recommend these Konis except where you want no-compromise performance and either trailer the car or are willing to put up with a kart-like ride. I suppose some of the coil-overs might be better, but I'm an H-Street'er.

BTW, some of the FiST guys I run against get plenty of rotation. Must be driving style. But we actually turn identical times.

Driving style, tires, luck.So many factors.

 

[Michaelquerty]

What are the manufacturer's torque specs anyway?

 

[Meowoosh]

About to install these and found that when both set to 3/4 hard (1 1/2 turns from full soft) they produced different results. I compressed both struts and released them at the same time. One of the struts was faster. I adjusted it by a small fraction of a turn and testes again and the struts were astonishingly close in damping speed. I just wanted to throw that info out there because I learned this from my 16-way adjustable Teins. Very few adjustments are apples to apples from shock to shock, for any brand. Always good to test, I dont know the exact values but at least I know they are the same.

 

[M-Sport fan]

About to install these and found that when both set to 3/4 hard (1 1/2 turns from full soft) they produced different results. I compressed both struts and released them at the same time. One of the struts was faster. I adjusted it by a small fraction of a turn and testes again and the struts were astonishingly close in damping speed. I just wanted to throw that info out there because I learned this from my 16-way adjustable Teins. Very few adjustments are apples to apples from shock to shock, for any brand. Always good to test, I dont know the exact values but at least I know they are the same.

This link addresses that issue in some detail (THANKS to welltal89! ); http://farnorthracing.com/autocross_secrets6.html

 

[Scotman2]

In an ideal world, we could call ITT Koni and purchase dyno matched pairs of front or rear Sport dampers. I dont think i'm alone here on that wish. Neither set of my Fiesta Koni Sports was matched. I had to visit a circle track shop near me that had a dyno and matched the settings max and minimum for me. I haven't noticed any degradation in 10k. But i am sure it's changed a bit. Fwiw i think any shock adjustments done without having your Fiesta at its prepared condition (whatever level that is) is a waste of effort. Even a few pounds here or there can change the end result.

 

[Stormy]

I noticed the same thing when I installed mine. One took about 1/8 of a turn more than the other to get them in sync.

 

[green_henry]

I'm installing Koni rears today and, darn, I wish the photo for step 7 in the original post was still there!

1. Does the stock, plastic dust cap get re-used? Doesn't seem like it fits, so I assume the flat plastic washer that's supplied with the strut is all that is necessary. Correct?
2. The stock setup only includes a single nut to secure the strut to the top mount. The Koni kit has two (identical) nuts. Do you just mount these on top of the other, the top one locking the bottom in place?

THANKS IN ADVANCE