Mk 8 GTI - new owner questions

[Carlosfandango]

@alland My understanding is, that ‘sports suspension’ when specced along with the 19” wheels, lowers the car by something like 15mm, this is why I had to have Eibach Pro-Kit springs fitted to my car when I replaced the factory fit 18’s, as the arch gap visually increased with 19’s on the car, this is also why there are two DCC options depending on wheel choice.

[Exonian]

The 15mm quoted ^^^ is compared to a base model Golf not a performance model which all have lowered suspension from the factory as compared to a Life, Match etc.

[Carlosfandango]

The 15mm quoted ^^^ is compared to a base model Golf not a performance model which all have lowered suspension from the factory as compared to a Life, Match etc.

The suspension on GTI’s with 18’s is definitely higher than those supplied with 19’s, the exact specifications I’m not sure of. The overall final ride height remains the same though due to the different wheel sizes in conjunction with the suspension changes.

[Exonian]

I’d say the difference you’re talking is the minuscule difference in overall diameter of the wheel and tyre combo going from 225/40/18 to 235/35/19 which will be not far off the equivalent to the difference between a new tyre and one at the legal minimum.
Seriously, too much internet gospel is taken from VW’s notoriously dodgy press bulletins and spec sheets.
The differences will be negligible. We are talking about splitting hairs here I’d imagine.
Happy to be proven wrong if presented with hard facts.
36 years of crawling around, in and under VW’s, modifying and de-modifying.

[Sharpe]

19” wheels with standard fit tyres will be 9.9mm larger overall diameter than 18” with standard fit tyres. Which is 4.95mm less arch gap and 4.95mm higher ride height. Depending of the offset (ET) they may poke out further which will also give the illusion of filling the arches more

[Exonian]

The factory 19” wheels are 8J ET50 not 8.5J and ET45 as in the table above so only 6mm or so extra “poke” but I do agree that wheel offset can visually make a big difference to how the wheel/tyre combo fills the arch.
Assuming the same rate of tyre wear at any given time then I guess you could say “every little helps” with the 5mm less arch gap.

I’m still to be convinced there’s much difference to the factory spring & damper set up between wheel size options. I’ve taken so many factory fit dampers off over the decades noting how little pressure is needed to compress the piston into the body and how slowly it pushes back out again compared to a good aftermarket damper. The main differences I noticed in the varying mk7’s I had (GTI PP, R, GTD, Ed40, TCR) were the spring rates.

[Carlosfandango]

I do not know that this is the case by any means @exonian, and I’m sure you’re correct about spring rates as that makes a lot of sense, , I’m simply basing my (now seemingly rather dubious😣) claim of height difference on 3 things, firstly Andrew Chapple (Volkswizard) mentioned something similar when he fitted 19’s to his club sport a couple of years back, secondly, just seeing the difference between my factory 18” GTI and a factory 19” GTI side by side at the dealership once I had 19’s on my car, and finally, being told that this was the case by Jamie @ Turner race developments when he fitted my Eibach springs in order to reduce the increased arch gap, I cannot confirm any of this however, and now question if I am at all correct! 😬
Maybe simply switching the wheels gave the illusion of a bigger arch gap?
https://www.turner-race-developments.co.uk/

[Exonian]

Of the three, I’d say your own eyes were the most reliable source!
Andrew’s net is cast quite wide.
TRD much more familiar with components as they’re working on cars constantly, but likely more familiar with things they sell rather than things they remove when it comes to tiny differences in factory specs. If it’s something significant such as larger bump stops to stop bigger wheels making contact on compression then I’d 100% trust them as there’s no arguing that, but factory dampers look very similar even if valving is slightly different and springs all look pretty much the same aside from the colour of paint blobs. If the windings were noticeably different and they’d seen enough examples of certain cars to take note then that would be really useful to know.
It’s just VW’s tech spec vagueness that brings out the cynicism in me.

An easy example is the 7.5 TCR where you had the standard passive suspension which was unknown spec but same ride height as the GTI Performance (same components?) and optional stand alone DCC (ditto GTI Perf) but the wheel and tyre DCC packs with the Reifnitz or Pretoria had “20mm” lower springs according to VW but in actuality that was 5mm compared to the other GTI’s (same ride height as Golf R in essence) plus front axle camber changes similar to the Clubsport S (and subsequently mk8 Clubby and R).
The springs on these optional packs were pretty firm and put me off DCC for life as the dampers couldn’t keep up with the springs unless set to firm, then it was just too firm!
Point being these specifics were mentioned in the press releases and tech specs albeit vaguely in most cases, but with the mk8 Golfs VW hint at things without any specifics making me very dubious.

[alland]

I don't have a great deal of knowledge about VW suspension dynamics as such, but back in the day a friend and I did quite a bit of rallying at National standard. In that scenario, the biggest influencer of suspension stiffness, comfort (yes, even in a rally wagon!) and ride height (even more important) was the springs. A huge amount depended on spring length, compression characteristic, and most of all, the actual steel the springs were made of - which was why aftermarket or specialised units were a lot dearer since they were made from superior quality steel than the stock items. Although we did use "sports" dampers (Koni) they had a secondary influence on handling.
So perhaps the same applies to modern day cars like our MK8 GTIs: lowered springs (and therefore less wheel arch gap (purely aesthetic), give progressive compression and therefore improved handling. Dampers (or shock absorbers as they were once known) do just that - absorb the shocks, albeit to varying degrees in the case of adjustable ones.
Of course, when we fit 19" wheels with 35 aspect-ration tyres, we're asking even more of the system!

[alland]

This may be a daft question, but has anyone noticed a reduction in the Mk8 GTI turning circle when 19" wheels are fitted? I ask because when manoeuvring my car the turning circle does not seem that good - although perfectly adequate once familiarised.
My Porsche Macan S had a similar trait, and the dealer told me that when larger wheels were installed (in this case 21"), stops were installed to limit the maximum steering movement in each direction to avoid the wheels contacting the inner bodywork and suspension components. Sounded like bullsh!t to me, so I never bothered about it.

I just wondered if VW did this on the Golfs