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Old 02-24-2010, 05:50 PM   #1
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Help - Need New Tire Advice - anybody gone taller?

Hey gang - I'm the proud new owner of a old car - an 01 "S" with 54k miles.

It has a worn set of extremely loud YOKELHAMA AVS 17's on there.

These things sound like a set of JC Penney Road Ranger studded snow tires.
(in case there's any other old guys out there that remember...)

They are AWFUL and my ears are bleeding.

I've been lurking the boards and discount tire sites, and the quality and price
choices are just about simply overwhelming.

I can spend $50.00 ea for some Chinese "Sunny" tires (does that sound
scary or what) or north of $300.00 ea for some variants of Michelin/Pirelli.

Which seems like highway robbery.

Stock - the 2001 S has 205/50/17 Front, and 255/40/17 Rear.

So, now to the question phase.

Has anybody put taller tires on the Boxster?

I have no interest in going 18" or 19".

Rather....

What I was thinking is going up one size in the series -
from 205/50 to 205/55 and 255/40 to 255/45

My nifty tire calculator indicates the fronts would be about 0.800in. larger
in diameter, and about 3.22 percent larger, so, 70mph indicated would
actually be running about 72.3 true. Not a super big deal.

These also would be about 0.61 percent different in diameter front to
back - not enough to confuse the ABS and whatever else is lurking in computer land.

Why?

It might seem sacrilege, but I'm after a slightly softer/quieter ride, and maybe
some longer treadwear.

Any favorite tires out there? I live in AZ - so the car will probably see rain 4 times a year, never be running below 45F.

Other than the occasional burst to 100, I'm never going to be running at felony speeds for extended periods, so the ZR rating is overkill too.

The taller tires might make turn in a bit more squishy, and ultimate skidpad numbers a bit lower, but truthfully, that's going to be hard for me to measure in my normal driving profile.

Thoughts?
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Old 02-24-2010, 06:46 PM   #2
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I don't think the tires are the issue....

I think you bought the wrong car
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Old 02-24-2010, 07:16 PM   #3
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Quote:
Originally Posted by TriGem2k
I don't think the tires are the issue....

I think you bought the wrong car
Umm, thanks for your help...I think.... oh... wait, Oh NOOO!!

Sudden AMAZING REALIZATION!

I bought the WRONG CAR!

Damn, that's gonna cost....

What WAS I Thinking?

Ya know - that kind of entered my mind, when I found out that U-Haul doesn't make a hitch for it, (how am I gonna tow the bass boat?) And there's no place for my 72 quart icechest, and the ground clearance is pretty lame for offroading, and the other day, at home depot - I was just scratching my head trying to figure out how to strap a 4x8 sheet of plywood onto the convertible top. But the good thing is, with two trunks, at least it will hold a couple concrete blocks, since I'm redoing the patio out back and all....

Actually, I found that the road hugging weight of the concrete blocks actually
cancelled out the net lift of the 4x8 plywood sheet, things didn't get really scary until I got it over 110 - finally had to back it off......

But, well, on second thought, sheesh - what a nice WARM welcome response to my FIRST post on this board -

Last edited by dr_gille; 02-24-2010 at 07:21 PM.
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Old 02-25-2010, 04:31 AM   #4
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Not having been on the board very long either, I will be the first to welcome you. Hopefully the response you got was done tongue in cheek but maybe not. I am sure you are not alone in your desires. Not all of us are obviously boy racers looking for that ultimate balance of handling and speed. If you are like me, you got the car because you can appreciate a well put together automobile that is more enjoyable to drive than your typical standard sedan. I can also appreciate your desire for some extra "cush" in the ride. I have several patches of terrible road surfaces on my way to work and it really rattles through the car. I also fear that some of the potholes may eventually overcome the low sidewalls and damage either the tire or wheel or both. But such is the compromises that are expected when owning a car like this. While increasing the wall height on the tires will obviously affect the handling, it is your choice on whether you can live with it or not.

If I had known that it was sacrilegious to not drive the car like a bat out of hell all time, I would have kept my ownership more of a secret .

Good luck with the car.
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Old 02-25-2010, 05:08 AM   #5
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My WAG is that your profile change won't cause any problems. Plenty of people have gone from a 265/40 to a 275/40 without issue, though this is a much smaller change in diameter.

One alternative might be a less performance oriented tire, such as an all-season tire, with softer side walls. Tirerack.com has ratings for ride comfort.
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Old 02-25-2010, 05:39 AM   #6
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Thanks for the welcome gsrhoden - in regards to an earlier post. I appreciate it.

I honestly think I'm going to pursue this for a while.

The naked truth is, the job of a tire is to stay in contact with the road. Unless
one is on a billiard table smooth skid-pad, bigger wheel and tire combinations
(+1, +2) will negatively impact performance in every measurable category
EXCEPT braking, and only if the reason for the move up was to install larger
rotors.

And/Or/If one spends Cubic Dollars on very light wheels and carbon ceramic
rotors. There are some especially deep pocket folks out there that can drop
$10 to 20k on brakes and wheels, but my budget is a tenth of that.

Larger wheels and tires are heavier. They have a greater flywheel effect
which requires more energy to spin up to speed, and then stores more energy
that has to be scrubbed off when slowing down, meaning extended stopping
distances, and increased brake wear.

There's also the increased gyroscopic effect of those four flywheels spinning
(which you really can't feel on a car that easily, but if you've been on a
motorcycle, the effect is obvious).

This gyroscopic effect of stored energy provides a net resistance to the car
changing direction. That impacts the nimbleness of cornering.

No Spin - No Proof. In many ways.

I darn near spun it last week, hooking into a corner and downshifting, and I
hit very small pressure ridge in the pavement, which the hard sidewall low profile
tires skittered across and the rear end broke loose.

Almost pulled a Speed Racer, headlights/tailights/headlights move.

I was surprised, because that Never happens in my Electra 225 (haha, just
messin with you guys...)...
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Old 02-25-2010, 06:07 AM   #7
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Tires

are an endlessly debated topic.

Go feel those rear Yokos. Bet they are cupped (irregular wear on the tread edges). Also they are known to be noisy when worn. Had a set, hated them, couldn't wait to get rid of them. Measured the decrease in noise by how many notches I was able to turn the radio down...4.

I wouldn't change tire size, just change to new tires and get a professional alignment done by someone who really knows how to set up a Boxster to favor even tire wear but still within Porsche specs. The idiot will set up to meet the spec but won't know what end of the spec to favor to get results. The really good alignment person probably sets cars up for racing and so understands the influence of the various measurements. Can double your rear tire mileage.

Three brands/models are constantly mentioned. Michelin PS2, Sumitomo HTR Z III and Kumho Ecsta SPT. They all make high performance summer radials to fit a Boxster with 17" wheels. The Michelin's are the benchmark against what tire testers test other tires but are expensive. If you buy them, make sure of the model number if you want the Porsche approved/tested version of the tire, it is slightly different from 3 other model numbers advertised under the same marketing name. The other 2 brands (Sumi/Kumho) are significantly cheaper.

Every tire has its proponents.
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Old 02-25-2010, 09:03 AM   #8
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Hmm... were you downshifting while "hooking" into the corner? ( sorry, I'm not sure what that phrase means )
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Old 02-25-2010, 09:20 AM   #9
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Gilly,

You forgot one benefit of taller sidewalls, they have a built in audible sensor to warn you of impending traction failure. More rubber equals more warning before you go assooverteakettle around some corner. 35s are not quite as friendly in this way.

I love your sense of humor, stick around and sooner or later we can BBQ some of the sacred cows that seem to be grazing this forum.
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Old 02-25-2010, 10:09 AM   #10
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Quote:
Originally Posted by dr_gille
Umm, thanks for your help...I think.... oh... wait, Oh NOOO!!

Sudden AMAZING REALIZATION!

I bought the WRONG CAR!

Damn, that's gonna cost....

What WAS I Thinking?

Ya know - that kind of entered my mind, when I found out that U-Haul doesn't make a hitch for it, (how am I gonna tow the bass boat?) And there's no place for my 72 quart icechest, and the ground clearance is pretty lame for offroading, and the other day, at home depot - I was just scratching my head trying to figure out how to strap a 4x8 sheet of plywood onto the convertible top. But the good thing is, with two trunks, at least it will hold a couple concrete blocks, since I'm redoing the patio out back and all....

Actually, I found that the road hugging weight of the concrete blocks actually
cancelled out the net lift of the 4x8 plywood sheet, things didn't get really scary until I got it over 110 - finally had to back it off......

But, well, on second thought, sheesh - what a nice WARM welcome response to my FIRST post on this board -
Dr, luckily you picked up the "S" model that has enough power to haul all that golly gee wizz stuff around.

Didn't realize it was your first post! Welcome to the fourm! Now, in all seriousness have you thought about going to the OEM 16" wheels and tires? This would give you the comfort your looking for and still being within all OEM specs. They are pretty cheap to pick up on ebay...

Not sure about the rear but when I had my factory 17's I had 225/45/17 in the front. I believe these have a slightly higher sidewall than the stock 205/50/17.

Good Luck Doc!
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2001 Boxster Artic Silver / Black Interior
-GT3 Front Bumper w/ Lip
-Side Skirts
-Gemballa Exhuast and Cats
-O.Z. Racing 18" Wheels
--18X8.5Front 18X10 Rears
-Michilen PS Tires 225/40/18 & 285/30/18
-5mm Rear Spacers
-Porsche Door Sills
-H&R Springs
-Powerflow Intake
-B&M Short Shifter
-Pioneer Avic-F90BT Navigation
-Focal Polyglass 165VR3
-Alpine PDX 5 Amp
-Bose OEM Subwoofer & Midrange
-Audio Controld DQXS (DSP)
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Old 02-25-2010, 05:04 PM   #11
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TriGem2: - thanks - all better...fur smoothed out..
Mista Wilson: Yup - downshifted, applied too much power, I equate hooking
with being a bit too hot... and this whole polar center of inertia kinda caught
up with me. Arguably, I'm a mid engine newbie, but no stranger to 11/10ths
driving.
mikefocke:'Zactly the input I was looking for. I've been leaning towards
the Michelins, but for the price of admission, they better be able to walk on
water. Might end up pondering on your top three, and then scouting out the
best deal available.

Back to TriGem2:
Actually, one of the things that crossed my mind was going to 16's. But closer
inspection revealed that in the front, the caliper is fairly tight, and in the back,
there's some suspension bits (tie rod end?) that are very close. I don't think
16's would fit.

I'm not sure what the delta was on dangly bits (i.e. rotor diameter, caliper sizing
blabla) between the various years of Boxti.

As my wife says "sweety - the sky is a different color in your world"... and I say
"ummm, yeah, that's 'cause I'm REALLY color blind - why do you think I bought
a yellow car? Its 'cause I can find it easy in the parking lot at work...."

Having said all that, I'm not above firing up Pro/E and designing up a wheel that
fits my specs. Something that will clear the suspension stuff, and still give me
a 16" diameter.

Why am I on this pursuit? Gather 'round the fire gents - its story time.

Back in '91, I happened to stop by Firebird Raceway, (south of Phoenix, AZ, where
I live) on a Saturday. They were having, for lack of a better word, some sort
of run-what-you-brung, historic sports car, get out on the track and beat the
crap outta your machine, drive-fest.

Firebird raceway has a long straight, a carousel at the end, and the backfield
return has some minor twistybits with bumpy spots off in the rough.

The cars were pretty much anything that qualified as SCCA from the late 50's
through the early 70's. MG's, Triumphs (TR4,5,6,7,8), Austin Healey, Jag, OSCA
Corvette, (Vic Edelbrock was taking some laps in his split window, until he
blew an oil cooler hose) and Porsche.

So, they had various heats during the day, and there would be half a dozen
"reasonably" matched cars out on the track. Truth of the matter was though,
that some of the cars couldn't have been more different.

It was an amazing opportunity to watch a vast spectrum of design engineering
solutions really get thrashed, and see who turns out on top.

There were two cars in particular that seemed particularly well matched, although
one was just slightly better than the other, always retaining the upper hand.

It was Jaguar against Porsche.

While they were matched, the two cars could not have been more different.

The Jaguar looked to be either an original, or re-created 62XKE- Low Drag Coupe,
or a 63/4 Factory Lightweight. The rubber on it was narrow, and tall on
famously sexy knockoff alloys.
In modern terms, probably 235/65/15's at best. The car was a coupe, and was dark green. It was slightly lowered, but not much.

The Porsche was a seriously flared and lowered 914 variant, Chrome Yellow,
and sounded smoother than a 4-pot, so I rather suspect it was pushing a 6.
Tires were steamroller 265/50/15's or whatever was close to that which could
have been available in '91. I don't think you could have rolled a pop can under
the car, it was very low, and there was almost zero travel to the suspension.
It had infinite roll stiffness.

Both cars were naturally aspirated, no turbos, and from the crackle of the
exhaust, and slightly rumply cams, I would estimate probably around 350hp
for either one. Could have been higher or lower but not by a hell of a lot.

The flag drops, and the Jag pulls out front because it just had better low
end torque. They headed down the straight first, and the Porsche got into
the power band and pulled up even with the Jag (on the right)
and stayed there until the end of the straight.

They both headed into the left carousel, the Porsche still to the outside of the
Jag on the corner. He had more grip, and had really wound it out on the straight
to keep up. The Jag had to slow down a bit, and almost lost it, but not enough
to let the Porsche ahead.

Then they hit the twisty bits. Some quick/tight bumpy left right stuff. The Porsche
had to drop back. He skittered and bounced through there like a hockey puck
on a brick patio. Flat, of course, but the tires were hardly touching the ground.

The Jag on the other hand, bounced and leaned like a baby carriage, but the
tires always stayed in contact with the road, and ultimately, it gripped
like a longclaw tomcat on shag carpeting.

The Porsche never passed the Jag.

It went on like this for 10 laps.

Even though the Porsche was 10 years newer in technology and easily had
twice as much tire on the road as the Jag, it couldn't use the traction, because
it wasn't on a high speed oval.

After that experience, I developed a serious case of Jag lust - but could never
wrap my head around the legendarily unreliable Lucas Electrics.

'Twas not to be.

My only solace was then to trundle out to the parking lot and hop in really, what
was a baby jag, my 1989 Miata. Sure, it gave up 150hp to the cat, and was actually HEAVIER than an XKE (ahh, the brilliance of monocoque)
But it was mine, and cornered like a slot car, and nobody could catch me going down a mountain.

I had a set of Michelins on that Miata. Got 60,000 miles out of them.
The Miata never broke. I revved it to redline EVERY SINGLE DAY I drove it, for
195,000 miles. Mobil1 from Day 1.
I would change the oil when I got around to it. Usually 3 to 6k.
After 17 years, it still had the original brake pads on it.
I only put 1 of the following on it. Clutch, waterpump, alternator, radiator.

That's it. During that time, I shudder to think what it would have cost to maintain
an old E-Type.

Nevertheless, the Miata finally had to go. That was 2 years ago. I have missed
it every day since, until three weeks ago when I bought the Boxster.

I did my homework. Actually would have wanted a 2005 and up, but they're
still fairly pricey. 2000 was the first year for the S, and first years for anything
usually aren't as good as the second year.

Late 90's Boxsters seemed to be having some teething pains, but its nice
to have the perspective of time passed to see what crops up.

So I bought an '01-S. 250hp vs 116 for the Miata should be a vast improvement.
It was a hangar queen, with only 54k on it. Just broken in.

The 01S is about as darn perfect as I could have dreamed. The torque of the
flat 6 is amazing, and second gear is a total hoot. Having 6 to row through
is a blast, although at times, 5th seems a bit superfluous.

My chief complaint has been the miserable tires it came with. As previously
mentioned, the YokelHama HowlMaster 3000's are louder than the radio,
louder than the exhaust, louder than Bubba's Monstertruk driving next to
me.

They are of course, the easiest thing to change. But to what?

My Quandary. And the Jag lesson. I drive in the real world.
Smooth, Fast, and as much under the radar as possible.

I really have no complaints with the ride. From a suspension standpoint.
Its reasonably compliant, has the correct amount of roll stiffness, and jounce.

The tires though. Sucketh Greatly. Jarring sidewalls, and NO WARNING of
IMPENDING DOOM. I would actually be faster down the road with tires that
let me know GRADUALLY that they are going to totally LET GO.

Arguably, if you haven't spun it, you're not trying hard enough, but I used
3 lanes getting a handle on this baby. I was a bit chastened, but happy
I didn't smack'er into the looming rock wall.

Overall, I'm exceptionally pleased with the car so far. Its my first from
der-faderland, and I'm looking forward to driving the wheels off it.
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Old 02-25-2010, 05:25 PM   #12
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Doc don't do it! Oh man you really did go on to tell a story, sorry to say I didn't get a chance to read it due to timing but I did want to reply with this...

All 986 16" wheels will fit your car... Heres a quick link

http://cgi.ebay.com/ebaymotors/Factory-original-Porsche-Boxster-16-inch-wheels_W0QQcmdZViewItemQQhashZitem1c0699889fQQitem Z120369809567QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fA ccessories

I promise i'll read the story later tonight when I've got some time to aborb it all
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2001 Boxster Artic Silver / Black Interior
-GT3 Front Bumper w/ Lip
-Side Skirts
-Gemballa Exhuast and Cats
-O.Z. Racing 18" Wheels
--18X8.5Front 18X10 Rears
-Michilen PS Tires 225/40/18 & 285/30/18
-5mm Rear Spacers
-Porsche Door Sills
-H&R Springs
-Powerflow Intake
-B&M Short Shifter
-Pioneer Avic-F90BT Navigation
-Focal Polyglass 165VR3
-Alpine PDX 5 Amp
-Bose OEM Subwoofer & Midrange
-Audio Controld DQXS (DSP)
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Old 02-26-2010, 05:13 AM   #13
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The 914 probably had no suspension travel left. Things get bouncy when there's no suspension movement, big tire sidewall or not.

Going up 3-4% in sidewall height will probably have no discernible change in ride comfort or ultimate grip, but a tire with a softer sidewall will.

As mentioned above, you might try an all-season tire that's less geared towards performance.

I've found the Boxster has a excellent grip on the road, even under bumpy corners. The camber settings on the rear end of this car are pretty aggressive and contribute to really good adhesion under cornering, especially for a strut-suspended car. Mine has the factory sport suspension, so it would tend to be a little more bouncy than stock.

I don't think the 16" wheel will fit an S. It was never offered on the S or the Carrera with the same brakes. Unless someone has 1st hand experience, I wouldn't bother.
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Old 02-26-2010, 06:04 AM   #14
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Welcome to the forum! Good story...I love vintage racing and go to as many events as time permits. Luckily, I live close by four great tracks (Blackhawk Farms, Autobahn CC, Gingerman and Road America) and not only spectate, but drive my '73 911 when finances permit.

As for your situation, I think Mike hit it on the head. It's not so much the size of the tires, it's the age and wear that's the problem. My friend bought an '02 S four years back with 15k miles on the clock and original Pirelli P-Zeros. They were hockey pucks; loud, no grip, just terrible, even though they had considerable tread left. I introduced him to my tire guy and he had a new set of Michelin Pilot Sports installed...the difference was night and day (these are 18s, mind you). As Mike said, rather than change tire specs, put on a fresh set of tires (your choice) with a proper alignment and you'll be very surprised by the difference.

Best of luck and enjoy the Box!
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Old 02-26-2010, 06:27 AM   #15
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Quote:
Originally Posted by jmatta
Welcome to the forum! Good story...I love vintage racing and go to as many events as time permits. Luckily, I live close by four great tracks (Blackhawk Farms, Autobahn CC, Gingerman and Road America) and not only spectate, but drive my '73 911 when finances permit.

As for your situation, I think Mike hit it on the head. It's not so much the size of the tires, it's the age and wear that's the problem. My friend bought an '02 S four years back with 15k miles on the clock and original Pirelli P-Zeros. They were hockey pucks; loud, no grip, just terrible, even though they had considerable tread left. I introduced him to my tire guy and he had a new set of Michelin Pilot Sports installed...the difference was night and day (these are 18s, mind you). As Mike said, rather than change tire specs, put on a fresh set of tires (your choice) with a proper alignment and you'll be very surprised by the difference.

Best of luck and enjoy the Box!
Confirmed. A good set of fresh quality rubber will be the cure. Old tires just suck. If the car is an "S" the factory 16s won't fit around the larger front brakes.
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Old 02-27-2010, 07:21 AM   #16
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When you do get new tires, try adjusting tire pressure slightly.
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