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Alloy wheels and suspension tuning


mike_true80
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Doesn't sounds like a manufacturer would go to the bother I know, but it does kind of make sense if you think about it. A 14" steel rim and appropriate section tyre has got to be heavier than a 17" lightweight alloy so theoretically you'd want to adjust the damper settings to compensate for the change in swing weight. Or am I miles off the mark?!

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Doesn't sounds like a manufacturer would go to the bother I know, but it does kind of make sense if you think about it. A 14" steel rim and appropriate section tyre has got to be heavier than a 17" lightweight alloy so theoretically you'd want to adjust the damper settings to compensate for the change in swing weight. Or am I miles off the mark?!

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Maybe, but you can only adjust the setting with factory kit by puutng on new kit, ie different dampers matched to different springs.

I guess tho, that most would only be moving from 16" to 17" or 17" to 18" and therefore no need to worry about suspension set-up.

I'd only consider suspension cahnges if you were going from 1" to 18" or thereabouts and need to check camber, aligment, toeing, etc,.

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Ah....I'm probably displaying my very limited knowledge....I know that the GTI does not have any OEM adaptive shocks etc but I thought that the ESP system read things like grip and weighting and compensated accordingly. My limited knowledge may mean I am confusing the two. I'm grateful for any education I can receive on this. 169144-ok.gif

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You're talking kack, I'm afraid Robin. The Mk5 GTI doesn't have active suspension.

ESP uses a combination of applying braking and very small amounts of power to different wheels to get the car back on track. Think of it as ABS with a bit more intelligence.

Re your original question True, unless a car is specified with a sports suspension pack (as in the Passat Sport), then the manufacturer doesn't do anything to the suspension.

The concept of "sport" with the sports suspension kind of missed the spot with the Passat Sport (Mrs Mook has one). It's 15mm lower than the standard Passat suspension and marginally stiffer than stock. But only marginally.

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I think we may be talking at cross purposes, Mook (though I will admit to talking kack from time to time!)....I think that "a combination of applying braking and very small amounts of power to different wheels to get the car back on track" is very similar to "sorts out snaking and helps kill wheelspin" (could be Robin-bird-poo though!). No active sus such as Koni FSD or Bilstein on the GTI - I know that.

The GTI has Sports Suspension, also stiffer and 15mm lower, as standard whereas the Mk5 Golfs don't (as far as I know!). Doubtless the new R32 has too.

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I think we may be talking at cross purposes, Mook (though I will admit to talking kack from time to time!)....I think that "a combination of applying braking and very small amounts of power to different wheels to get the car back on track" is very similar to "sorts out snaking and helps kill wheelspin" (could be Robin-bird-poo though!). No active sus such as Koni FSD or Bilstein on the GTI - I know that.

The GTI has Sports Suspension, also stiffer and 15mm lower, as standard whereas the Mk5 Golfs don't (as far as I know!). Doubtless the new R32 has too.

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So, does the GTi have electronic diff - to vary the power between left and right wheels when slip is detected. I thought it only controlled the power to both wheels, ie slip detected so power is reduce until grip is regained.

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Individual braking is applied to the spinning wheel and power is knocked back. This is all controlled via traction part of the ECU, with sensors on the wheel hub figuring out that the spinning wheel shouldn't be doing 60 mph when the car is only doing 30!

Take a look at your hub next time you take the wheel off. Behind the disk and caliper assembly, there is a disk with slotted holes in it. There is a sensor mounted behind this which sends the signals back to the ECU.

All clever stuff 169144-ok.gif

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....Thanks for answering that Mook - I was def about to either unload some more bird-poo or be left dazed and confused a la LedZep.

I understand then that you are saying that each individual wheel's grip is detected as opposed to as SixDegrees has written.

Isn't all this independent of suspension behaviour?

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Isn't all this independent of suspension behaviour?

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Yes it is, but you can't take each individual element in it's own right. If you uprate the suspension, you change the way that wheels are loaded - more downward pressure is applied.

So on a GTI with standard suspension, where the inside wheel lifts, you will find it does this less on one with uprated suspension, as the outside wheel will not be able to rise up as much and the inside wheel will be pushed down harder (i.e. you are reducing the roll of the car).

The single best thing you can do to a Mk5 GTI to improve its handling without going to the expense of uprating the shock absorbers and springs is to uprate the anti-roll bars (reduces roll) and add a top strut brace (stiffens the front of the car without compromising ride comfort).

All of this will help you to dial out the understeer, although if you want to dial it out completely, you'll need to get an .:R32... tongue.gif

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Thanks for all the info, Mook....Very helpful (and of course part of what TSN is all about 169144-ok.gif). Having driven a track spec Mk5 GTI with Bilstein shocks and springs and Eibach anti-roll bars I have at least experienced a different and very 'planted' feel which suspension mods can add (that particular car also has Porsche brakes but that's another subject). I'm only considering road use and exploring my options before making any decisions.

A fellow TSNer I have actually met has very kindly offered me a drive in his GTI fitted with Eibach anti-roll bars and springs and the new Koni FSD 'active' shocks. That sounds like my favourite option but the first stage option you suggest of only fitting anti-roll bars plus top strut brace is def worth my consideration....Another quezzie I'm afraid is if I did this 'first stage' which included a top strut brace, would I need to remove that top strut when/if I moved to next stage of fitting Koni FSD shocks and Eibach springs?

I'm not feeling that the standard GTI is inadequate but rather that I have experienced how it can be improved - Fatal !!

The R32? You ordering a new one methinks 169144-ok.gif I probably would have have bought one if it had been available at the same time as the GTI....4WD + V6 sound is very attractive, but....perhaps next time.

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I'm sure that Mook can answer this better than I but I do know that on the Mk5 GTI each of the 4 wheels is separately monitored for any lack of grip and that ESP is an 'umbrella' term for additional technology such as ABS. My understanding is that it works on all four and not just two wheels. This process is separate from mechanical suspension but perhaps the effects of suspension in turn influence the ESP's reaction.

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Opps, aye I meant all 4 wheels when talking about the braking aspect of control.

Can someone list the safety functions that the GTi has, ie ASR, ABS, etc (usually 3 letters)

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taken from the gti catalogue:

ASR,ESP,ABS and HBA (hydralic brake assist)

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The single best thing you can do to a Mk5 GTI to improve its handling without going to the expense of uprating the shock absorbers and springs is to uprate the anti-roll bars (reduces roll) and add a top strut brace (stiffens the front of the car without compromising ride comfort).

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....Mook, I'm told that I wouldn't notice any difference when driving a GTI with the added top strut brace. Obviously I would notice the difference with just anti-roll bars but to fit in two stages for springs and shocks. I would be doubling some of my labour costs. I'm gonna wait and drive a Koni FSD car and then choose Koni or Bilstein but probably Koni FSD better suited for road use.

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[ QUOTE ]

[ QUOTE ]

Opps, aye I meant all 4 wheels when talking about the braking aspect of control.

Can someone list the safety functions that the GTi has, ie ASR, ABS, etc (usually 3 letters)

[/ QUOTE ]

taken from the gti catalogue:

ASR,ESP,ABS and HBA (hydralic brake assist)

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Do Golfs have EDL as well. Read that some where (Electronic Diff Lock), works in conjunction with ASR or ABS, not sure which!

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