35 vs 40 sidewall tires & ride comfort

Would going to 40 sidewall from a 35 provide any noticeable difference in ride quality? My current tires are 235/35/19 and 285/35/19 with M030 suspension. While it's great on smooth roads, it a little harsh on the typical LA pothole ridden streets. Would I have any clearance issues going to a 40 assuming I kept the same section width?

40 going to be alot taller, if you have a low spring it probibly wont work. 35 is too tall for rears, they should be 30 anyway bigger tire you get the more soft it will ride. but its probibly your 030 shocks that make it hard in the first place

Get 18" wheels, much better

Correction. I have 30 in the front 35 in the rear. Love the wheels and really don't want to change them. Looks like I'd have space for 35F & 40R??

[QUOTE=OKB;13941222]40 going to be alot taller, if you have a low spring it probibly wont work. 35 is too tall for rears, they should be 30 anyway bigger tire you get the more soft it will ride. but its probibly your 030 shocks that make it hard in the first place[ /QUOTE] THIS - & what are you PSI's - not the recommended ones on the sticker - way to high - lower will be better - grip, wear and comfort. IMHO.

There's a section of freeway here that makes it feel like the car is falling apart. And that's with stock 18s (30 profile rear, 35 front). See where you're coming from but damn those 19s look good.

I run 35 profile 265/35-18 in rear - at 38-40 psi ride is good - I think you only need to go to 44 if you are going to run extended periods above 100mph on the autobahn .....

Yes, my 030 shocks were hard as a brick. I now have Koni's installed just one turn or less from full soft and noticeably better ride though still firm.

That sounds backwards with lower profile in the front. There rear tires are wider so in order to maintain diameter, you would need a lower profile in the raer

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My WAG is even if you find a set of tires that fit without any clearance issues the difference between the 35 to the 40 sidewall will not be that much. FWIW when I explored having the M030 suspension fitted to my Boxster the Porsche techs talked me out of it. Both said while it was great on the track the ride would be too harsh on the street which is where my car spends all of its time. Certainly you can try the 40 tires if you can find a set that will fit/clear in the hope I am wrong. A caution: If you have a 4 with AWD you have to be sure you select a set of tires that are compatible with the differences in revs per mile the factory sanctioned tire sets provide. If you violate this you can render the AWD ineffective, or actually cause the AWD to turn into some kind of brake, or worse ruin the viscous coupling/front diff. You might consider -- it is more expensive but perhaps you can the sell the 19" and recoup some of the cost -- switching to 18" wheels. This may not help much though. When I went from driving my Boxster with its 17" wheels to my 2008 Cayman S with 18" wheels the ride difference was considerable. The Cayman S ride made the Boxster ride feel as smooth as a magic carpet. Same when I switch from driving my Boxster to my 996 Turbo with 18" wheels. 'course, the Turbo is more stiffly sprung than the Boxster but the wheel/tire diameters do make a difference.

It's a C2. For now I think I'll try different tire pressures. Since the tires and suspension are all new and it's mainly a weekend car used for canyon runs I can live with it. Down the road I may try a slightly taller tire and different shock.

How old are your tires? Old tires suck for ride comfort. Playing with tire pressures is a good idea.

Tires are new.

Go 36/40. Then try 1PSI less. See if you like it better. Repeat till you find a sweet spot.

Bash, your wheels are freakishly clean. What do you use (a team of Siberian dwarves with Bon Ami?)

Ha! No, just plain ol' unicorn semen.

I was told at an Indy that deals with nothing but Porsches that i should go 32 Front and 36 back - that is on a 996 40th AE - standard size 18" s - Pirreli P Zero's. It made a huge difference to the ride comfort and the grip and feel was not subtle! But it also has the US M030 and it's hard - something i want to change maybe H&R Road performance Coilovers or similar.

I'm running 285/40/18 in the rear on my street tires and I have a problem with PSM kicking on whenever I let off the throttle at high speeds (above 85 or so). The problem doesn't occur when I'm running my 315/30/18 rears with the racing tires. The 40 really is that much taller that it not only looks goofy but messes with ABS/ PSM. I would say that running 18" wheels instead of 19 would be your best bet at improving ride quality.

2000 C2. X74 stock tire size. I use 31-32f, 36r. Rule of thumb, one pound per hundred, add 2-4 for wherever the engine. Fine tune from there.

rough starting point, set front pressure (Pf) to (weight/100)+2, i.e. a 3000lb car would start at 32psi front. From there calculate starting rear pressure as Pf*((Wr*Xf)/(Wf*Xr)) where Wr is rear weight, Wf is front weight, Xf is front tire width, and Xr is rear tire width. As an example, for a 3000lb car with 55% rear weight and 225/255 tires, it comes out as 32*((1650*225)/(1350*255))=34.5psi rear tire pressure. YMMV

My car with 19" wheels and shorter sidewall tires had an appreciably bumpier ride than it now does with 18" wheels and stock-height sidewalls. It's not "Oh my GOD" better, but a solid "say, that's better."

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What oil are you using and what is the electrolyte composition?

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I don't mean to answer for 5CHN3LL, but I'm pretty sure he's using an organic compound versus a full synthetic, as the organic has what plants crave. We could all take a lesson from his playbook

How on earth did this one turn into an oil thread?? Is nowhere safe!!

Nope Expect the unexpected

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Tire pressure experimentation is certainly worth trying. With my 996 Turbo the tire pressures on the decal inside the gas cap lid are for a fully loaded vehicle. When I have the car in for service the tech sets the tire pressures to a few PSI less than the pressures listed on the decal. I'm sure you won't but just to get this out there you don't want to go overboard regarding pressures. There is of course the problem of running the pressures too low the tire runs too hot. While you probably won't go up with tire pressures with my Boxster I have found that overinflated tires -- at least at the front -- can result in some vague vibrations that suggest tire imbalance but are "cured" by simply lowering the pressure.