Andyoz Posted May 9, 2021 Share Posted May 9, 2021 Hi, I'm in Nth Ireland and we have some mega roads here but some of the surfaces vary alot. I'm toying with the idea of having a second set of rims in 18" (or even 17" if front calipers will clear them?). My deadline will be for this mega drive in October. Nearly a week of 8hr daily stints with buckets and 19" rims will not be pretty for this 51yo... I'm gathering up options. So far, Andrea gave me two good ones: ATS-GTR and Apex SM-10. One issue with 18" rims is you can't get PS4S for them but I can deal with thatm Link to comment Share on other sites More sharing options...
wtaite01 Posted May 9, 2021 Share Posted May 9, 2021 3 hours ago, Andyoz said: Hi, I'm in Nth Ireland and we have some mega roads here but some of the surfaces vary alot. I'm toying with the idea of having a second set of rims in 18" (or even 17" if front calipers will clear them?). My deadline will be for this mega drive in October. Nearly a week of 8hr daily stints with buckets and 19" rims will not be pretty for this 51yo... I'm gathering up options. So far, Andrea gave me two good ones: ATS-GTR and Apex SM-10. One issue with 18" rims is you can't get PS4S for them but I can deal with thatm Regarding the PS4 S, while you can't get them in 18 inch sizes, you can get the new Bridgestone Potenza Sport in 18 inch sizes. They are generally equaling or beating the PS4 S in the tyre tests currently, so I wouldn't worry too much about tyre choices on 18s: https://www.tyrereviews.com/Tyre/Bridgestone/Potenza-Sport.htm Link to comment Share on other sites More sharing options...
Kdh Posted May 9, 2021 Share Posted May 9, 2021 I have a set of black 18" wheels with Pilot Sport N4's for sale here: Link to comment Share on other sites More sharing options...
wtaite01 Posted May 9, 2021 Share Posted May 9, 2021 I think the race cars use OZ Alleggerita HLTs (according to Parr motorsport when I asked them). They come in factory offsets and widths too on the 18s and are really light compared to OEM rims. Check out the 'Weight Table' under product details below: https://www.ozracing.com/uk/alloy-wheels/oz-racing/i-tech/alleggerita-hlt I believe the S, R and base all use the same size discs up front, didn't they? If so, then in theory the factory 17s would fit, and are cheap too (I picked mine up for £100 with tyres!). They are skinnier though, (205/235 section vs 235/265 on the 18s and 19s) so may not be right for the higher power of the R and S. Link to comment Share on other sites More sharing options...
Andyoz Posted May 9, 2021 Author Share Posted May 9, 2021 39 minutes ago, wtaite01 said: I think the race cars use OZ Alleggerita HLTs (according to Parr motorsport when I asked them). They come in factory offsets and widths too on the 18s and are really light compared to OEM rims. Check out the 'Weight Table' under product details below: https://www.ozracing.com/uk/alloy-wheels/oz-racing/i-tech/alleggerita-hlt I believe the S, R and base all use the same size discs up front, didn't they? If so, then in theory the factory 17s would fit, and are cheap too (I picked mine up for £100 with tyres!). They are skinnier though, (205/235 section vs 235/265 on the 18s and 19s) so may not be right for the higher power of the R and S. Yeah, I did spot the UOz racing ones. Be great to source a used pair as I've got 5 months to look. Not sure where lads advertise that sort of thing. I'll post on Porsche Facebook and forums as stuff eventually turns up if patient... Link to comment Share on other sites More sharing options...
zcacogp Posted May 10, 2021 Share Posted May 10, 2021 10 hours ago, eponymoose said: 18s don't feel that different to the 19s. 17s is where the real benefits are. They'll fit with front spacers. But the look could be challenging on an R! I'm going to get a set of 17s for my S. Had enough of the 18s. Fitting 17s was a revelation on my last Cayman S. I do prefer the look of the 18s, just acutely dislike the way they drive in a road context. This. Exactly this. Thanks Mr eponymoose, that's precisely my thoughts; anything bigger than 17's on a 987 ruins the handling. My 987.1 non-S with PASM is a joy and a delight on 17's but with 18's then the delicacy and precision is lost, only to be replaced by numbness and lack of feel, with a boatload more road noise for added misery. Link to comment Share on other sites More sharing options...
Andyoz Posted May 10, 2021 Author Share Posted May 10, 2021 (edited) Do the front calipers on an S fit a 17" rim? They won't be permanent but I'd fit them if I knew I was doing a multi day session where I don't worry about looks all that much. Edited May 10, 2021 by Andyoz Link to comment Share on other sites More sharing options...
zcacogp Posted May 10, 2021 Share Posted May 10, 2021 Interesting, why not use 17's for track work Eponymoose? Link to comment Share on other sites More sharing options...
Lennym1984 Posted May 10, 2021 Share Posted May 10, 2021 Just now, eponymoose said: I wouldn't go 17s for track work. I've driven the Ring (and conventional track days) on 17s, not great! But for the road, they are transformative. I'd concur with this assessment. I used to have both 17s and 18s and whilst the 17s were lovely on the road, the compromise was less front end grip (at road speeds/Gs it's fine/nice but on track it just feels lacking). A wide tyre on the front of the 17s may be a solution but for me, it was easier just to use 18s. Switching back to 18s after running 17s for a few weeks used to feel like strapping lead boots to the front of the car so I'd fully agree with everything Eponymoose is saying. Link to comment Share on other sites More sharing options...
Andyoz Posted May 10, 2021 Author Share Posted May 10, 2021 I still think 18's are the best compromise I will be able to get. Link to comment Share on other sites More sharing options...
wtaite01 Posted May 10, 2021 Share Posted May 10, 2021 Would be interesting to understand where the 17s preferable qualities come from. For example: Lower weight - Aftermarket 18s may be able to match this even with tyres on, those OZ ones are that light Smaller section - 18s can't match this in OE sizes Larger sidewall - 18s can't match this in OE sizes I suspect that most of the added feel through the front end is due to the smaller section, but as for the ride improvements, how much of this comes from the higher sidewall vs the lower weight for the suspension to control I don't know. Link to comment Share on other sites More sharing options...
zcacogp Posted May 10, 2021 Share Posted May 10, 2021 27 minutes ago, wtaite01 said: Would be interesting to understand where the 17s preferable qualities come from. For example: Lower weight - Aftermarket 18s may be able to match this even with tyres on, those OZ ones are that light Smaller section - 18s can't match this in OE sizes Larger sidewall - 18s can't match this in OE sizes I suspect that most of the added feel through the front end is due to the smaller section, but as for the ride improvements, how much of this comes from the higher sidewall vs the lower weight for the suspension to control I don't know. That's a really interesting question. I guess it must be those two things; more sidewall compliance and smaller section. I think that there is a weight element in there as well; my comparison is between the standard 18inch Cayman S wheels and the smaller 17's as fitted to some models of Boxster (I think). These and these: Admittedly I am not comparing like with like as the tyres on them are different (winters on the 17's, summers on the 18's, different brands in each case). I have also noticed a fair fuel economy penalty since I went up to 18's, which I suspect is due to their greater rolling and wind resistance. Another reason to keep things small. Link to comment Share on other sites More sharing options...
Lennym1984 Posted May 10, 2021 Share Posted May 10, 2021 (edited) I'd guess that weight and sidewall is the driver of the difference. Tyre weight will add to this - A 17" tyre in 205/235 profile will weigh considerably less than an 18 or 19" 235/265 equivalent Edited May 10, 2021 by Lennym1984 Link to comment Share on other sites More sharing options...
andygo Posted May 10, 2021 Share Posted May 10, 2021 If I was forced to run a 17" wheel with wobbly 50 series tyres, I'd probably settle for a classic MGB or mx5. One of the selling points of the Toyota GT86 was that it was deliberatly under tyred so it was a bit slidey. Personally I would rather have grip and move the performance envelope upwards rather than downwards. Porsche suspension is more than compliant enough to cope, especially if you watch where you are driving. Link to comment Share on other sites More sharing options...
wtaite01 Posted May 12, 2021 Share Posted May 12, 2021 Have run the numbers on the weights because I'm that dull! Quite interesting results. For reference, the tyres are Pilot Sport 2 in all cases, with the weights taken from tirerack website. Had to convert from lbs to kg. Tyre sizes are OEM: 205/55 R17, 235/50 R17, 235/40 R18 and 265/40 R18. The OEM wheels are the 17" 987.1 base cayman wheels and the 18" 987.1 Cayman S wheels with the weight taken from http://www.944racing.de/wheelweights.php. The 987.2 wheel weights aren't on there, but the 17" would likely be a bit heavier as they're 7 inch at the front rather than 6.5, and I don't know about the 18". The OZ aftermarket wheels are the OZ Alleggerita HLTs referenced above in both 9" and 10" rear options (OEM Cayman S 18s are 9"). Tyre weights are very similar, so I guess that the change in sidewall vs section largely cancel each other out, so it does largely come down to the wheel weights in the example above. 18" OEM heaviest by some margin, but the lightweight aftermarket OZs actually appear to be the lightest combination over all, though not by much. The total weight for all 4 wheels does make you realise quite how much unsprung, rotational mass you are carrying around! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now