I am after some advice, hopefully from someone who competes in the BRSCC Porsche Championship or the PCGB Boxster Cup.
I have a 2005 987 Boxster S and for the last 2 years I have started using it on Track days. Back in September I noticed my front right shock was leaking and decided to replace all the shocks with BC coilovers, the other week I finally went to drive the car out the garage and noticed that the rear left alloy was catching on the coilover.
The alloys that are fitted are Team Dynamics 1.3's the front being 18"x8.5 ET44 & the rear is 18"x10 ET47, from factory it should be, front 18"x8 ET 57 & rear 18"x9 ET43. Basically according to an online calculator this means the front has an additional offset of 7mm and is 12.5mm additional width on the outer edge of the tyre, the rear however has come in by 16.5mm and extended by 8.5mm hence why it is catching on the coilover.
I have spoke to the guy who is going to do a corner weight and alignment setup for me, he has advised that he does not recommend stretching the tyres like this as although it gives good initial feel for entry to the corner after that point it only gives you negative handling and ultimately will be slower, he has also said he is going to look to see what they run on their cars and let me know. He also said he strongly suggests I do not run spacers on track due to the extra forces.
This got me thinking so I looked up the regs for the BRSCC and PCGB, the PCGB is open and you can use what ever you like but the BRSCC in 2019 were running these exact alloys, which I am assuming who ever fitted these might have copied this from (I have owned the car since 2017 so the regs might have been different before then). The BRSCC also says you can run spacers.
I am after some advice as to whether these alloys are ruining the handling on my car due to messing with the scrub radius and stretching the tyres and if these are alloys are fine then how much should I space the rear out by? I think the lowest I could go would be 7 maybe 6mm to stop it from rubbing.
From browsing the internet the go to spacer sizes are 7mm front and 15mm rear but I believe these are on standard alloys not these larger ones, as the front is already 7mm out from standard should I put a 15mm in the rear as it will just fit before fowling the arch.
Obviously the primary use of the car should be for the road as it is not a dedicated track car, but I would rather it drove better on track and be manageable on the road if that makes sense.
Any help would be greatly appreciated
Thanks
Paul
I have a 2005 987 Boxster S and for the last 2 years I have started using it on Track days. Back in September I noticed my front right shock was leaking and decided to replace all the shocks with BC coilovers, the other week I finally went to drive the car out the garage and noticed that the rear left alloy was catching on the coilover.
The alloys that are fitted are Team Dynamics 1.3's the front being 18"x8.5 ET44 & the rear is 18"x10 ET47, from factory it should be, front 18"x8 ET 57 & rear 18"x9 ET43. Basically according to an online calculator this means the front has an additional offset of 7mm and is 12.5mm additional width on the outer edge of the tyre, the rear however has come in by 16.5mm and extended by 8.5mm hence why it is catching on the coilover.
I have spoke to the guy who is going to do a corner weight and alignment setup for me, he has advised that he does not recommend stretching the tyres like this as although it gives good initial feel for entry to the corner after that point it only gives you negative handling and ultimately will be slower, he has also said he is going to look to see what they run on their cars and let me know. He also said he strongly suggests I do not run spacers on track due to the extra forces.
This got me thinking so I looked up the regs for the BRSCC and PCGB, the PCGB is open and you can use what ever you like but the BRSCC in 2019 were running these exact alloys, which I am assuming who ever fitted these might have copied this from (I have owned the car since 2017 so the regs might have been different before then). The BRSCC also says you can run spacers.
I am after some advice as to whether these alloys are ruining the handling on my car due to messing with the scrub radius and stretching the tyres and if these are alloys are fine then how much should I space the rear out by? I think the lowest I could go would be 7 maybe 6mm to stop it from rubbing.
From browsing the internet the go to spacer sizes are 7mm front and 15mm rear but I believe these are on standard alloys not these larger ones, as the front is already 7mm out from standard should I put a 15mm in the rear as it will just fit before fowling the arch.
Obviously the primary use of the car should be for the road as it is not a dedicated track car, but I would rather it drove better on track and be manageable on the road if that makes sense.
Any help would be greatly appreciated
Thanks
Paul
