½cwt Posted November 27, 2019 Report Share Posted November 27, 2019 I've been doing some research ahead of budget capacity at the moment but I'm looking at tyres for my new 18" rims for my 3.2S. Porsche recommend standard load not extra load for the Boxster, but some of the N homologated tyres are extra load such as the Michelin PS2, whereas the Pirelli P Zero Rosso is standard load. What is the difference other than the total load capacity of the tyre? I imagine the side wall would be stiffer on an extra load tyre and therefore a harder ride. I also note that the extra load tyres typically have a better fuel consumption rating not that that is of great concern. When I bought the new front tyres for my 17" rims I went for a standard load tyre (GY Asymetric) to stay inline with the N rated tyres although the one I chose on that occasion wasn't N rated. Does anyone have the technical explanation? Link to comment Share on other sites More sharing options...
PaulQ Posted November 28, 2019 Report Share Posted November 28, 2019 Not exactly technical, but the following gives you a good insight. Would be interesting to see a cross section of two otherwise identical tyres other then load rating. https://www.oponeo.co.uk/blog/reinforced-tyres-advantages-and-disadvantages Link to comment Share on other sites More sharing options...
GmanB Posted November 29, 2019 Report Share Posted November 29, 2019 Great article there @PaulQ. I have Eagle F1's Asymmetric 3 on mine during the summer and those are reinforced, honestly didn't even realise until looking. They're a great tyre on 18's. Unfortunately I have nothing to compare it to as I put them on when I bought the car. I'd imagine the car feels a bit stiffer than a tyre that isn't reinforced, but would you noticeable feel it? I really can't wait to get Asymmetric 5's on the car, but I'd imagine that won't be until July or August next year. Any way the grip is superb on the Eagles and I'd recommend them to anyone. Around £500 fitted all round is decent value. Link to comment Share on other sites More sharing options...
Rev Ken Posted December 1, 2019 Report Share Posted December 1, 2019 I thought 'extra load' tyres were for extra heave vehicles, which certainly doesn't include Boxsters! 'Normal' tyres with the correct speed ratings do for me! Link to comment Share on other sites More sharing options...
½cwt Posted December 2, 2019 Author Report Share Posted December 2, 2019 9 hours ago, Rev Ken said: I thought 'extra load' tyres were for extra heave vehicles, which certainly doesn't include Boxsters! 'Normal' tyres with the correct speed ratings do for me! However, many tyres in Boxster sizes for 18" rims (Mich, GY etc) are extra load..... only Pirelli of the premium brands seem to have a standard load front and rear options. Hence my question. Link to comment Share on other sites More sharing options...
PaulQ Posted December 2, 2019 Report Share Posted December 2, 2019 32 minutes ago, ½cwt said: However, many tyres in Boxster sizes for 18" rims (Mich, GY etc) are extra load..... only Pirelli of the premium brands seem to have a standard load front and rear options. Hence my question. You can get an (n3) 225/45/17 Pilot Sport 2 in XL, while the Pirelli equivalent (n3 & 5) is SL..... no idea what cars they are for though. Link to comment Share on other sites More sharing options...
mike597 Posted December 2, 2019 Report Share Posted December 2, 2019 11 hours ago, Rev Ken said: I thought 'extra load' tyres were for extra heave vehicles, which certainly doesn't include Boxsters! 'Normal' tyres with the correct speed ratings do for me! I thought that as well. But my wife's car is spec's with XL tyres. It's a Volvo V40 Cross country. Basically a Ford Focus in a Swedish frock. When I changed the tyres recently I checked and rechecked that but I couldn't get a sensible answer as to why. Link to comment Share on other sites More sharing options...
Patt Posted December 2, 2019 Report Share Posted December 2, 2019 I've always chosen the XL tyres in the past - seem to think the side walls were stiffer. (I've not clicked the link) Link to comment Share on other sites More sharing options...
Pinewood Posted December 2, 2019 Report Share Posted December 2, 2019 Michelin pilot sport 2 (N2) and are XL. They are more comfortable than the normal load tyres they replaced. Link to comment Share on other sites More sharing options...
½cwt Posted December 2, 2019 Author Report Share Posted December 2, 2019 A bit more research has shown that an XL tyre in the size ranges applicable to Boxsters adds around 60 -70 kg to the permissible max working load and that an XL tyre will sustain a higher inflation pressure, neither of which seem applicable as such. Also give that a standard load tyre in these size ranges give a max load of high 500s to low 600s kg range and a 3.2 986 weights in at 1250kg so even with a lot of dynamic load transfer the requirement for XL is redundant. I have noted that XL tyres typically have a better fuel rating on the Tyre Label that is required these days. It does also seem that the lower aspect ratio or profile, the more likely only XL tyres are available. I'm beginning to think that the main reason an apparent over spec tyre may be specified is because it has a lower rolling resistance due to a stiffer tread/shoulder and so even if not required as a spec for a given vehicle gives better eco performance when it comes to official data. Given the apparent additional stiffness of XL tyres @Pinewood makes an interesting comment, although when I swapped the old Bridgestone S-02s from the front for new GY Asymetics, both standard load, on my 17" rims the front felt more complaint as well as grippy (may have been 205/50 to 225/45 width change as well...) so different brand and tyre age may factor in too. Maybe these things are not just round, black and much of a muchness after all and, as Martin Brundle was saying in commentary from Abu Dhabi at the weekend, voodoo happens between the tyre and the road. Link to comment Share on other sites More sharing options...
Pinewood Posted December 2, 2019 Report Share Posted December 2, 2019 "voodoo happens between the tyre and road" Great saying 😊👍 Link to comment Share on other sites More sharing options...
Mattman42 Posted December 2, 2019 Report Share Posted December 2, 2019 When researching replacement front tyres for my 987, i didn't get any choice, every single option stated was XL - perhaps because they are 235/35/19's and need the stiffer side wall at this size? Link to comment Share on other sites More sharing options...
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