Pirelli P4000 Super Touring Tread Widths

[Bob S.]

Hi Folks -

Would somebody be kind enough to measure tread widths for the 215/70ZR-15 97W and a 205/70ZR-15 95W Pirelli P4000 tires?

I've been unable to find these specs on either the Tire Rack or Pirelli websites......

Furthermore, if someone really has nothing better to do, would they be willing to measure the total section widths of these two tires and report them along with the rim widths they're mounted on? (The Tire Rack's specs for these 2 tires look a little strange to me: It appears they would have essentially the same section width if measured on the same witdh rim, and not close to the .4" difference one might expect....)

Tire Rack specs for Pirelli P4000 Super Touring Tires:
205/70-15: 8.5" wide measured on a 6.0" rim
215/70-15: 8.7" wide measured on a 6.5" rim

I know I'm being a "weenie", but the 215/70-15 XH4 Michelin's I have now will rub inside the front fender lip at only moderate steering angles. I've measured their treads to be about 7.0" wide vs the 205/70-15 XH4's that are about 6.5". (This is with 6.0" wide Western K-O's that I measure to appear to have similar offset to the '67 rallye wheel.)

Thanks,
Bob S.

[Duke W.]

Re: Pirelli P4000 Super Touring Tread Widths

Measuring tread width can be a slipperly slope because it's often a judgment call as to where the tread/sidewall "border" actually is.

This is particularly true with higher profile radial designs because they tend to have rounded rather than square shoulders as is typical on low profile radial designs. This is probably one reason why you often don't see "tread width" called out on the spec sheets.

The "measuring" or "design" wheel is the wheel width used to take the nominal dimensions of the inflated tire, and the section width should be close to the metric size of the tire on the design wheel; 215 mm is about 8.5".

Acceptable dimensions promulgated by The Tire and Rim Assc. for a given tire size are in fairly narrow ranges.

The other issue to consider is that overall section width will change about 40 percent of a change in wheel width, so if you decrease wheel width 0.5 inch, the measured maximum section width should decrease by about 0.2", so the nominal section width of the 215/70 on a 6" wheel should be about 8.5".

The repro KOs with adapter should measure the same .06" offset as the base '67 Rally wheels.

Fender lip interference can be caused by too much positive camber. I recommend zero degrees camber at the front and -0.5 degrees at the rear for "touring", and -1 degree all around for maximum handling performance.

A one degree change of camber in the negative direction increases fender lip clearance by about a quarter inch, which is significant, so you should check your camber.

Reports by several owners who run the 215/70ZR-15 P4000 Super Touring indicate no fender lip interference on any C2 with any OE wheel, but .060"
offset wheels on disk brake cars yield the tightest clearance.

It's typical for 205/70s to rub the steering gear carriage bolt heads at full left lock, but since full lock is only engaged at parking lot speeds, it's not a safety issue.

You have a typo in your list of tire widths - should be 70, not 50.

Duke

[Bob S.]

Re: Pirelli P4000 Super Touring Tread Widths

The other issue to consider is that overall section width will change about 40 percent of a change in wheel width, so if you decrease wheel width 0.5 inch, the measured maximum section width should decrease by about 0.2", so the nominal section width of the 215/70 on a 6" wheel should be about 8.5".
Duke

And thus the reason for the second part of my question......the 205's and 215's would then BOTH have a section width of 8.5". Doesn't make sense to me.....

Bob

[Duke W.]

Re: Pirelli P4000 Super Touring Tread Widths

The specified dimensions are approximate and rounded to the nearest tenth. I'm sure if you measured both carefully on the same width wheel the 205 would be a few tenths narrower than the 215.

There's also a chance that there is an error in the data.

About ten years ago I pointed out an error to a manufacturer, and they were so appreciative they gave me a set of tires. What's ironic is that the error is still there on the spec sheet. They never corrected it!

Most 205/70R-15s have a specified width of 8.0-8.2" on a 6" wide wheel.

Duke

[Jimmy B.]

Re: Pirelli P4000 Super Touring Tread Widths

Bob,

I have a brand new set of these tires unmounted in size P215 70ZR15 on my garage shelf - thanks to Duke's recommendation, I am putting these on my 67 as soon as it returns from the paint shop. Would you like a photo of the tread width on these? Would this answer your question?

Jim Blakely

[Bob S.]

Re: Pirelli P4000 Super Touring Tread Widths

Jimmy - Thanks! That would be great, especially if you could lay a ruler or tape measure across the tread for scale.

I'm planning to buy a set of P4000's for both my cars (one a '67 with original 'DG' Rallyes), but wish to have that last bit of confidence before I commit.

Maybe I'm beating a dead horse, but I'm just trying to be sure after finding the Michelin 215/70-15's rub inside the front fenders....it appears the Michelins are quite a "broad shouldered" tire.

Thanks for the help!

Bob S.

[Bob S.]

Re: Pirelli P4000 Super Touring Tread Widths

There's also a chance that there is an error in the data.

Most 205/70R-15s have a specified width of 8.0-8.2" on a 6" wide wheel.

Duke

Duke - That's just what I was thinking! The 8.7" appears typical for a 215/70-15 on a 6.5" rim.

Bob

[Jimmy B.]

Re: Pirelli P4000 Super Touring Tread Widths

Sorry it took me so long, busy getting ready for my new Corvette arrival.

Need any more photos let me know.

Jim Blakely

My wife assisted me in these photos.

[Jimmy B.]

Re: Pirelli P4000 Super Touring Tread Widths

couple more pictures

[Mark P.]

Re: Pirelli P4000 Super Touring Tread Widths

I just realized my rear camber must be set wrong thanks to Duke's posting.

Yesterday after getting the new P4000's installed I noticed the passenger side rear clearance was tighter than the drivers side rear clearance and that lip had some wear (approx 1/4") from where the tires were rubbing.

The P4000's were the same exact size as the previous tires and show no sign of rubbing so I am certain the lip wear has been there for a while.

When I measure the shortest distance from the lip to the tire it is 1" on the rear passenger side and 1.5" on the drivers side. The distance from the garage floor to the lip is the same for both sides at 25 1/2".

I am going to read up on how to set the camber and go with -1 all the way around for best handling. Should I just take it to an alignment shop or is this something that many owner's do themselves ?

My front fender lips are 26" off the garage floor. Is this 1/2 difference from the rear normal or an indication of rear spring sag ?

[Duke W.]

Re: Pirelli P4000 Super Touring Tread Widths

Go to a hardware store and buy a decent inclinometer. You can use it to measure and adjust camber as long as you have a level surface.
Most home garages will suffice.

I do all my alignment with a tape measure and inclinometer. I haven't been to an alignment shop in 30 years.

If you search "inclinometer" in the archives you should find detailed posts on DIY alignement.


Duke

[Terry M.]

Re: Pirelli P4000 Super Touring Tread Widths

In the later 1970s, when Corvette began to come with radial tires, Chevrolet changed the recommended rear camber setting to 0*. I do not have enough experience with radials on my C3 to offer you a recommendation -- but it might be worth considering that setting.

[Mark P.]

Re: Pirelli P4000 Super Touring Tread Widths

That compass thing is what was coming up when I searched for "inclinometer":

http://en.wikipedia.org/wiki/Clinometer

Other alignment pages I found referred to a Protractor which I am guessing is probably the same as the inclinometer.

[Duke W.]

Re: Pirelli P4000 Super Touring Tread Widths

Get in the friggin' car and go to a hardware store. Hold the instrument in your hand. You want one with the longest possible base to lay against the tire sidewall of wheel flange.

The photo looks like some kind of campass... I don't know.

Duke

[Zale P.]

Re: Pirelli P4000 Super Touring Tread Widths

I have 215/70/15 Michelins V rated on my 1966 L36 and I have no problem with fender clearance anywhere..

Although after Dan Martin replaced my springs all around the car rose up about 3.5 inches.... The goofy thing had dropped down like it was a low rider..

Probably why I have good clearance is because Dan got the car height correct..

Cheers, Zale