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Problems fitting uniballs due to variations in rear arm sleeve dimensions

  • With fit problem MY14

    Votes: 0 0.0%
  • Without fit problem MY14

    Votes: 4 16.0%
  • With fit problem MY15

    Votes: 3 12.0%
  • Without fit problem MY15

    Votes: 9 36.0%
  • With fit problem MY16

    Votes: 4 16.0%
  • Without fit problem MY16

    Votes: 1 4.0%
  • With fit problem MY17

    Votes: 0 0.0%
  • Without fit problem MY17

    Votes: 2 8.0%
  • With fit problem MY18

    Votes: 0 0.0%
  • Without fit problem MY18

    Votes: 2 8.0%
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Voted no for problems on a MY15 LE. The uniballs, in combination with Advans running 225/265 RT615K+ instead of the PZeros, and more driver education, resulted in a 5 second improvement in my PR on a 1.7 mile course. I have total confidence in the car.
No doubt unibals do good to the handling and improve significantly stability/predictability/confidence.
But to be realistic - 5 sec time gain is probably mostly due to 1. better rubber, 2. wider rubber, 3. unibals.
Anyway - 5 seconds is huge, really WOW
 

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Discussion Starter · #422 ·
I agree. It is hard to say that uniballs give you 5 sec off the lap on its own. But the confidence that is provided by fixing the rear end dynamic alignment change could be that 5 seconds. In my case, tires and uniballs were 7.5s on 2 min. long, high speed curvy track. It is my home track, very well known to me. I just really couldn't bring stock 4C to the limit and keep it there, and feel confident, so I guess I was driving below the limit. Perhaps there are better drivers, that can fully utilize stock 4C, but my driving style didn't go along very well with so much dynamic alignment change 4C has. And the better the tires, the more obvious the problem gets. I had semicslicks before uniballs and it I could feel the extra grip, but the car felt even more floaty and disconnected.
 

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Yes, that’s very much the point while under warranty. I’m happy with the speed at which my transmission changes gear. I have had a go of a 4C with a Scara73 remap thanks to alfa1105 and that is a level beyond standard. Fast and smooth with no clunks you occasionally get with the oem tcm software. Very impressive. No experience with the Alfaworks one.
I just messaged Scara73 for a price on a remapped transmission ecu to compare. Alfaworks one isn't available right now anyway.
 

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Are TCU remaps more of benefit in auto or manual? or both? Trying to decide if I need it more than something else I could spend £700 on... my tyres look worn in the middle on the back!
Hmmm...suggest Safety FIRST!
TIRES! Just my humble opinion, also check tire pressures, usually middle wearing is reflective of over inflation...
my 0.02 cents :)
 

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Agreed @Croc and @GMS. I didn’t want to go out there on new tires without the uniballs, so I can’t say how much one contributed over the other. I know the tires made a big difference. But stock tires/bushings I wasn’t comfortable on high speed sweepers. Enough that it confused a different instructor why I was fast on a more dangerous turn and not in the relatively safer sweeper. The confidence to add speed in those corners and know it will stay, to throw it around in the slower sharp corners, well the uniballs and tires both get credit for that.
 

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Got the rear arms from GMS installed last week and thank you Rudi for the awesome support. The alignment was a pain but I found a good guy who did the whole thing and he has a race background. To do it right he had to test drive and realign the whole car for three times to be sure that it's okay. So don't trust those alignment shops who do it in an hour or less - it isn't enough to get the whole car right unless it's just the front toe you are dealing with.

With the uniball bushes the car is finally stable and goes where I want it to. Last summer I tested my friend's Cayman GT4 and it cornered so much better than the 4C - with the rear arms, right camber, caster and toe I don't fall behind during cornering. For some reason the stock setting has a low negative camber that Alfa decided to compensate by having a toe out. Dunno if they also had the low stock castor for easier steering due to the lack of power assisted steering. The front toe out was one of the reasons why the reviews bashed the car so much but the fix is easy.
 

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Discussion Starter · #430 ·
Appreciated. (y)

I did a fair share of alignments on 4C's myself. Yesterday I spend roughly 4h aligning customer's 4C after we installed camber / caster plates and uniballs at the rear. I wanted to get it as perfect as I could as I find 4C among the most alignment sensitive cars I ever worked on.

Your findings about the 4C unusual stock alignment is accurate. To make sure the steering doesn't feel too heavy on parking manoeuvres, they dialled out almost all the caster (stock spec is about +2° - 2.5° only). This makes front end feeling unresponsive light at speed and prone to tramlining. To get back some of the steering response they added quite a bit of front toe out. This helps with the turn-in but even further increases tramlining. Final thing, the more negative camber you add, the worse the tramlining gets. So with stock alignment you get pretty messed up driving experience. As mentioned, luckily it is a relative easy fix and makes the 4C handle as sharp some of the most precise and good feedback providing cars I've ever driven.

🏁
 

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Discussion Starter · #431 ·
Recently got question from one of the alignment shops as they were unsure about setting up 4C.

Indeed, the adjustment was well off as they didn't convert the units properly. Some alignment shops have their alignment machines setup to show decimal degrees, others degrees and minutes and third millimeters or inches.

All the GMS alignments specs are given in degrees and minutes as these are the most precise.

Example:

+0° 30' (degrees and minutes) = +0.5° (decimal degrees) > use this calculator: Degrees,minutes,seconds to decimal degrees converter

+0° 30' (degrees and minutes) = 3.7mm (milimeters on 17") or 4.0mm (milimeters on 18") > It is necessary to take into account the wheel diameter! Use this calculator: http://www.trackace.co.uk/Manual/Conversion Chart.pdf
 

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Discussion Starter · #432 ·
After 3 years since releasing the GMS uniballs for rear arms, we have exactly 0% failure rate so far. I ran the prototype version made of lesser material and no heat treated material for 40.000km, mostly heavy driving and still they run flawlessly. No free play, no excessive friction. We have also sold quite a few sets for Tesla Model S which is notorious for having short life span of stock uniballs. Zero failures so far. The failures that did happen, were in all cases due to improper installation process. To solve this issue and, we now offer a set of special pressing adapters to make the job of GMS uniball installation easier for you and your workshop. Improper installation now cannot happen - I think. 😁 There is still a chance that your rear arm hole bores are out of spec and uniballs won't fit, so custom size uniballs or complete rear arms with uniballs preinstalled are available.

Detailed photos will follow...

You can order set of pressing adapters here: ALFA ROMEO - 4C - Rear arm uniball pressing adapter set | GaleMotorSport
 

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Oh HECK... those would have been a nice addition. You should include them in the price of the set. Keep people from screwing them up!
 
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