Wheel spacers - Do they improve handling?

[Gibbo205]

Hi there

OK guys don't shoot me down, this is an honest genuine question. The GT3 has 5mm spacers fitted to it as standard to give it a wider track or so I believe, this is a factory option from Porsche for all 911 Carrera's so I can buy these from OPC and have no issue with warranty:-

http://www.suncoastparts.com/product/00004450009.h...

Or there is also 17mm versions available too, again from OPC so within warranty allowance:-

http://www.suncoastparts.com/product/HubCentric.ht...


So from what I can gather it seems the 5mm spacers are a good upgrade for handling improvements as it widens track slightly. Question is would going to 17mm spacer give an even greater improvement, if so what are the drawbacks if any?

I do a few track days in my car so anything that further improves handling is a big bonus, there is obviously stuff such as GT3 swaybars and lower control arms too, but those will void warranty unless I can convince OPC to think otherwise, but doubtful.

[Gibbo205]

Wozy68 said:

Blimey, 17MM per side?

Do you remember (old enough) the advert for Benson & Hedges cigars?

The fella who fitted the Carlos Fandango wheels to his (Was it an Anglia?) car.

All was going well until he tried to drive it through a narrow field gate after fitting them, and left the wheels behind.

Queue music.

Yes 17mm seems too much to me and I'd imagine the wheels would stick out from the arches, but am sure there are some here running them, be good to here there thoughts along with any suspension experts. Maybe it is just safer to go with the 5mm kit as fitted to GT3's as standard as wheels will still be within arches, its minor so should give the right look without being OTT and maybe a small handling improvement.

[Gibbo205]

Ian_UK1 said:

I have Tequipment 5mm spacers on my car all round. I also have the Carrera Sport wheels that are 13mm wider than standard, front and back. This means is that the outside edge of all the wheels on my car sit 11.5mm (half of the 13mm extra width of the wheels + 5mm of spacer) further out from the car's centreline than standard. This leaves the tyres absolutely flush with the body, giving an aggressive stance but no contact between the tyres and the arches (see piccy below). Going any further would cause issues, I think, so 17mm is probably too far.

Edited by Ian_UK1 on Wednesday 16th May 16:26

Thanks m8, think I shall go with 5mm kit all round, OPC have said zero issues with warranty and it seems all that have done say the same, makes front-end feel less nervous, though I have to say my car does not seem nervous on the front.

One last question, are wheel spacers compatible with PCCB equipped cars?

[Gibbo205]

Hi there

I am thinking 7mm front and 5mm rear will give best result, slightly wider stance on front to dial the understeer out a little.

[Gibbo205]

Ian_UK1 said:

If you have standard width/offset wheels on your '7S, 11.5mm spacers would place the outside edges of your wheels in the same place as mine. I've seen both 10mm and 12mm available from various sources - one or other of these would probably be the best compromise.

Bear in mind you will also need longer wheel bolts and your geo will need to be tweaked too - the loading on the suspension will be different with the wheels further outboard. The only real downside with spacers is that they all, to some extent, put increased load on the wheel bearings. I don't think it's a major issue with relatively narrow ones though (such as 10mm or thereabouts).

As for using larger spacers on the front than the rear - I've no idea what the effect on handling might be (or even if I'm remotely a good-enough driver to detect it). Spacers are cheap enough to experiment with, but getting the geo redone every time would be an expensive PITA. I also wonder if the car might look 'odd' with the front wheels flush to the body and the rear wheels inboard of the arches.

Chris Franklin from COG recommends on a 997 S just stick 5mm spacers on the front to reduce understeer. Adding spacers all round he says give an overall improvement to stability/control but in order to dial out understeer the front track needs to be wider, seemed to make sense.

For now gone with 7mm front and 5mm rear, as this should have the desired positive effect on handling and look a little better though not quite as spot on as yours. If I like the intial results I shall then get the GEO re-measured and adjusted if need be.

[Gibbo205]

scarebus said:

I read this with great interest as I am desperate to dial out the understeer of my C2s which drives me insane on track.
It would be nice if you could play around with the front spacers combinations and see what gives the best results, timed videoed laps of your local round about would be nice

Gibbo, whats the story with getting rid of the PCCBs on your other thread? Are you having any issues with them?

The fronts are nearly shot, I do another track day on them and I risk ruining them, right now they still have plenty of road use in them, but not for track. So for track I want to go steels or try to source a spare set of front ceramics.

After speaking to several who seem in the know I've been told to do the following:-
- tyre pressures, higher front pressure and lower rear pressure helps reduce understeer but all your doing is shifting grip around, not actually improving anything. But give them a go.
- wheel spacers, adding to just front helps give front more grip due to wider track, also supposedly gives a less nervous feeling. Adding them all round gives an overall grip and control improvement but to help dial out understeer the front needs to be wider. Wheel spacers of course don't cost much, you must use right bolts!
- GT3 sway bars, lighter and adjustable, these supposedly direct fit and work well.
- GT3 or RSS front lower arms to get upto -3 degrees camber, this will definitely work.
- wider front tyres, stickier tyres etc.

I'm gonna give the 7mm and 5mm a try, got a few test roundabouts and am at Donny 7th July.

[Gibbo205]

Phooey said:

Just a thought... but wouldn't Porsche fit them as standard, if they improved handling?

They are an extra cost option when speccing a new car and Porsche sell them.