BGTS front end floaty - Page 2 - Boxster/Cayman - PistonHeads UK

Hi all I have '22 BGTS and recently went from the factory fit Pirelli PZeroes to Mich PS4s. I'm running (hot) 30psi front and 32 rear. I find that when I press on the front is distinctly un-planted and feels light and floaty, rather prone to very mild bump steer when in this state. Overall the grip *is* still there but it doesnt feel quite as good as the PZs. Which is a surprise. No other changes btw. And factory geo. Could it be pressures?

My Cayman came with Pirelli's the ones everyone said were rubbish, I found the turn-in with them very good, when they wore out I switched to Michelins and found the very same vague feeling you describe, I put it down to perhaps the Michelin's have a more supple sidewall which has more give vs the Pirelli's stiffer construction. Well that was my thinking anyway.

Tyre pressures are way too low. You should, imo, be running 30-32psi all round when cold. Tyre pressures will rise to ~35psi when they get hot. Also have a look at getting a 4 wheel alignment done. The MPS4S side wall is much softer than the PZ4 so this may also be something you're experiencing when driving spiritedly.

You need more air in your tyres for a kick off.

I'll try that

I had a 2020 BGTS which had PS4s and replaced them like for like, last year got a new one which came on pireli - and I have to say they are very good tyres, maybe not so good in the winter (i have winter wheel set anyway to swap to), but I can't see why everyone praises michelin so much.

I have Pirellis PZ4 on my GTS 4.0 and use it all year round. I've got a set of winters in the garage but havent found the need to put them on for the last 2 winters. Pirellis are fine.

scrounger73 said: Tyre pressures are way too low. You should, imo, be running 30-32psi all round when cold. Tyre pressures will rise to ~35psi when they get hot. Also have a look at getting a 4 wheel alignment done. This. 2.4 bar (~35 psi) is good all round when hot IMO.

What is a BGTS?

maz8062 said: What is a BGTS? Posted in a Porsche Boxster and Cayman specific subforum? You really can't work it out?

Boxster GTS

Funnily enough I’ve gone back to PS4S on the front from PZ4. The PZ 4 is definitely better on turn in, as someone else has pointed out the sidewalls are stiffer. The PZ4 also has better steering feel I found. I run around 32 psi cold. The pressures ramp up faster with the PS4 S during fast driving which is another downside, likely due to sidewall flexing. A mistake in my case given most of my driving is on relatively deserted roads where it’s possible to extend the car.

Pirelli’s are great in the dry, but absolutely awful in the wet. PS4S or literally anything else even Linglong ditchfinders are preferable if you drive the car year round.

I like PS4S, had a few sets on my 981…but Conti Sport Contact 7 has moved the game on. Great tyre.

Toyota-MR23 said: Pirelli s are great in the dry, but absolutely awful in the wet. PS4S or literally anything else even Linglong ditchfinders are preferable if you drive the car year round. I have to disagree I'm afraid. If you've been used to driving previous versions of the P-Zero then you may be right however the PZ4 is a great all year round tyre per se. Had them on my GTS 4.0 for 4 years now and run them throughout the winter. I do have a set of winters in my garage but we haven't had a real snow for a couple of years and so haven't had the need to put them on.

Try getting a Thinkdiag OBD dongle or a Piwis and selecting a GT4 steering map from the cars native selection. Transformed the feel on my 981 GTS. Best £100 I have ever spent on my car. Lots of info here: https://rennlist.com/forums/991/1384044-thinkdiag-...

scrounger73 said: I have to disagree I'm afraid. If you've been used to driving previous versions of the P-Zero then you may be right however the PZ4 is a great all year round tyre per se. Had them on my GTS 4.0 for 4 years now and run them throughout the winter. I do have a set of winters in my garage but we haven't had a real snow for a couple of years and so haven't had the need to put them on. Respectfully disagree mate. For winters without needing to switch to dedicated winters probably says more about the UK’s recent mild seasons than the PZ4’s actual capability, I wouldn’t take that as a strong endorsement personally. The fundamental problem with the P Zero on new Porsches is the OE compound. It’s factory tuned to prioritise rolling resistance and noise over outright grip and longevity, which suits Porsches homologation data nicely but doesn’t really serve the driver. Wet braking and lateral grip in the cold and damp is where it really falls short, and that’s exactly where a sports tyre on a 4.0 GTS should be earning its money. Michelin Pilot Sport 5 is a better tyre by most measurable metrics at a similar price and the Continental SportContact 7 outperforms it in nearly every independant test I’ve seen. The P Zero name carries a lot of weight from its motorsport heritage but the road tyre is trading pretty heavily on that history rather than actually delivering on it.

Toyota-MR23 said: Michelin Pilot Sport 5 is a better tyre by most measurable metrics at a similar price and the Continental SportContact 7 outperforms it in nearly every independant test I ve seen. Problem is you can't get those in N rated spec as of yet but I'll be waiting for the PZ5 which is supposed to be better than anything else out there at the minute....allegedly. I have to agree on the Conti though. My Son has them on his i20N and loves them over the standard fit Pirellis that were awful. Like I said, personally, I'll stick with the PZ but back to the OPs issue, it's most likely the softer sidewall on the Michelin and tyre pressures that are too low.

It’s a known issue with PS4S - they don’t have the initial bite at the front when you turn in. Outright grip is excellent, but if your tanking on and turn into a fast sweeper it has a tendency to run wide until you learn to compensate, but it’s not a particularly great tyre on a Cayman as it’s a car that benefits from a responsive front axle more than some. The PZ4 surprised me and is definitely a big step up from older gen P Zero. I use my car in the wet as well as the dry on wet roads, it never felt lacking in grip. I don’t get huge mileage given my use ( 4K front 2/2.5 k rear ). The C 7 is excellent but you pay the price with longevity. The PZ also had better steering feel and kept its grip all the way down the tread on the front.

maz8062 said: What is a BGTS? A new MG Restomod, perhaps? I was wondering too. When seeing the What's New postings list it is not always clear which section it was under.

Well, at 34ish all round (hot) its deffo better. But my dashcam is taking G-triggered photos all over the place! Soooo much harsher ride. I'll need to find a middle ground I think

Turn the G meter down on your dashcam. The ride will be slightly harsher as you've increased your pressures.

I just don't get why the Michelins get so much love, sure they are comfy, quiet, grippy, and in the wet very impressive, but, and it is a big but, they absolutely ruin the super sharp steering and turn in that you are meant to have with a Porsche. It is the rear tyres that give you this not the fronts. As you turn and accelerate all the weight is on the rear and the sidewall being far too soft just means you get a sort of wobble effect as the tyre simply can't handle it. I ditched mine after 1000 miles, it was not a compromise I was willing to make. I will just add though that mine were not N rated, they are meant to have a stiffer sidewall and the compound on the outside 1/3 of the tyres is also mean to be a lot firmer, which should help. But I wouldn't risk it again as I found the off the shelf version so poor last time.

scrounger73 said: Problem is you can't get those in N rated spec as of yet but I'll be waiting for the PZ5 which is supposed to be better than anything else out there at the minute....allegedly. I have to agree on the Conti though. My Son has them on his i20N and loves them over the standard fit Pirellis that were awful. Like I said, personally, I'll stick with the PZ but back to the OPs issue, it's most likely the softer sidewall on the Michelin and tyre pressures that are too low. N-rated isn't a requirement for warranty any more.

andygo said: Try getting a Thinkdiag OBD dongle or a Piwis and selecting a GT4 steering map from the cars native selection. Transformed the feel on my 981 GTS. Best £100 I have ever spent on my car. Lots of info here: https://rennlist.com/forums/991/1384044-thinkdiag-... Done (bought a ThinkDiag), good tip *but* seems 718 doesnt have those steering profiles I did enable my rain wipers (still can't figure out if its working though but for sure menu is there now). I also have enabled the option to save HVAC settings to the key when car car is locked (I have the memory package). It always struck me as bizzare that you had to explictly remember to save using the door card button! Tyres now at 32-33 psi ish (warm) and its "ok".

You should be running at 30-32 cold, not warm.

Then it warms to 35-36 and its uncomfortably hard P Zeros next time