newbie question- wheel spacers 18 in to 17 inch wheels

[RobP44]

Hi
Can I ask for advice as a new member- apologies if all covered before and if an obvious question.- I have limited mechanical knowledge!

I have a gen 2 2010 987 Boxster it came with black 18 inch cayman s ii alloy wheels (I think designation 409. I prefer the look of regular silver wheels and bought a set of 17 inch from eBay (I think designation code 393) -and thought I could swap over in a cost effective way

I thought would be simple to swap over - but then realised I needed a low level jack, (and bought axle stands), a torque wrench, breaker bar, wheel hangars and aluminium paste- so perhaps not as cost effective as I first thought.

Then tried to fit and realised the disc callipers were touching the wheel- so then learnt about the world of spacers which looks to be another level of complexity.

Admittedly I could take to the local garage- but where is the fun in that?

My questions

-What is the minimum size spacers do I need?
-need both for front and back?
-any particular recommendations for make or vendor?
-will I need longer nuts..??

Thanks
Rob

 

[mr pg]

Don't think spacers are the solution as the calipers are still going to be well within the rim, and so still be touching.

 

[RobP44]

Thanks
Is there a solution or do I stick with my current wheels?
Rob

 

[Motorhead]

Rob,

I think that the 987-series Cayman had 18" wheels as standard, so as Paul says the calipers may well foul with 17" wheels, and no amount of spacing will help.

Just be aware that although various Porsche wheels may look the same, because they were available on Boxsters/Caymans and the 911 the offsets may be different for the mid-engined and rear-engined cars, as although the front suspensions are the same the rear suspension designs are very different.

The only thing you could do is to offer the wheels up to get some idea what spacer size you'd need to prevent fouling. I think you'll find that a number of spacer sizes are available from Porsche, and you'd need longer bolts to go with them. Apart from the Porsche Dealerships, companies like Design911 and PorscheShop should be able to supply the necessary parts, and you could always contact them for advice.

I've never been a great fan of wheel spacers. Unless used with the correct wheel offset they can load the wheel bearings incorrectly and mess-up the handling. Personally, I'd stick with your current 18" wheels for which the car was designed.

Jeff

 

[RobP44]

Thanks Jeff
Thats very helpful.
I will contact my local garage for advice.
I did think the base Boxster both 987 and 987.2 had 17inch as standard but I may be wrong here
Thanks again
Rob

 

[AndrewT]

Is your 987.2 Boxster a 2.9, not an S?

I had a Cayman 987.2 2.9 which came with 17” wheels which the original owner sourced from his local OPC, I believe that the were Boxster wheels, anyway they fitted OK with no spacers. Maybe the 17” wheels you bought are from a 986/7 Boxster and perhaps you need wheels from a 987.2 Boxster. When I had new pads and discs fitted to that car the Porsche Specialist said the 987.2 Cayman had the same size discs and pads as the 987.2 S, that may explain the difficulty you’re having.

Here’s a picture of the 17” wheels on my Cayman.

 

[RobP44]

HiAndrew- its a base 987.2 not an S.
That makes sense too-I will talk to the garage
Thanks
Rob

 

[AndrewT]

I’ve checked, it looks like you need Boxster 987 Base III wheels.

 

[AndrewT]

You have the Boxster Base II wheels for the 986.
Do a google search for Boxster 987 Techquipment and also Porsche PET diagrams where you’ll find some useful information.

 

[RobP44]

Thanks Andrew
the code inside the wheel is 987.362.122.05- I will look through the techquipment site
Rob

 

[RobP44]

From the PET site I should have got
987.362.125.01- oh well!
Thanks again
Rob

 

[AndrewT]

Rob,

I just saw your post on PH which prompted me to look again for a Boxster 986 Techquipment page, my previous screenshot excluded the note which applies to the ‘1’ tag on the Base II wheels - it says to fit them on a 986 you need 5mm spacers all round. That should work assuming that the 987.2 discs/caliper do not present a larger diameter than will fit within the wheel.

Could you temporarily fit washers or even cardboad to mimic a 5mm spacer, the existing bolts should be long enough, just to test it while it is on the jack/axle stands?

https://www.porsche-iberica.com/pt/porscheservice/pdf/TEQ_986_II_MY06_gb.pdf

 

[Motorhead]

I reckon that the Cayman looks rather dinky on the 17" wheels Rob - and yes, I'd forgotten that winter tyres used the 17" rims, so ones with the appropriate offset and inner rim diameter should fit OK. Having said that, surely the correct 17" wheels shouldn't require spacers? As you've found out, Porsche wheels present a bit of a minefield..!

One advantage of the smaller wheels should be an improvement in ride quality as the tyre sidewalls are much taller and therefore more flexible. I run 19" wheels on my 987.2 CS and although firm, the ride quality is more than acceptable with the PASM option which - being continuously active - has a slightly softer damper set-up for normal driving than standard.

Jeff

 

[RobP44]

Hi Jeff/Andrew
Thanks for your further replies.
I have just tried the back wheels and they fit ok with plenty of space.
The front wheels rub against the outward facing side of the disc caliper but other wise seem to fit ok (see pic)
I tried the cardboard and i think a 5-7.5 mm spacer should be ok. I see the porsche shop sell them 3-6 mm at about £30 (will check if need longer bolts) and a 7.5mm at £300.
I will email them and ask.
Thanks again for your help
Rob

 

[mr pg]

You will need the longer bolts which are identified by the red anodised collar. The standard bolts would have insufficient thread engagement and run the risk of coming loose. I have 5mm spacers on my 981CS.

 

[RobP44]

Thanks - may i ask where you got your spacers?
Rob