What tires are you using

[Norm Peterson]

Originally Posted by URBAN LEGEND

325/30/19 RE 11 is a perfect fit on 11" inch wide rims. Shouldn't be the case but it is.

Within recommended rim width limits, yes (just barely).

But a little too much 'bulge'.


Norm

[URBAN LEGEND]

Originally Posted by Norm Peterson

Within recommended rim width limits, yes (just barely).

But a little too much 'bulge'.


Norm

Zero bulge here. Zero.

[YOLO Z/28]

Originally Posted by DavidCorsaro

The PS4S was used by many competitors during this year's One Lap of America. Reports are that is a fantastic all-rounder, sacrificing a bit of ultimate grip for gobs of wet weather capability and excellent wear characteristics.

A friend/fellow autocrosser who was lucky enough to enter the competition this year with his '15 1LE said he had enough tire afterwards to repeat the event and mileage all over again.

This is perfect! Thanks for the input.

[Norm Peterson]

Originally Posted by URBAN LEGEND

Zero bulge here. Zero.

Ummmm . . . no. You've clearly got some. That doesn't necessarily make it wrong (as long as the wheel is at least min-recommended width). Just bulged.

The amount of sidewall out past the outer face of the wheel's flange is 'bulge' and represents at least that much further the tire will distort in a corner or 'bend' to accommodate bumps. Wheel widths narrower than 'measuring width' for the tire size mounted on them are in fact slightly 'squeezed' or 'pinched' fitments.




Not nearly as much as this ↓↓↓




But more than this ↓↓↓ , which is still bulged a little (measuring wheel width fitment).




You have to get out near maximum-recommended width fitments before the bulge completely disappears. Yes, this is a slightly stretched fitment (actual rim wider than measuring).




Norm

[TonyNDeb]

[QUOTE=URBAN LEGEND;9816753]

Originally Posted by TonyNDeb

Tire Rack doesn't know the Bridgestones run narrow.

But I wasn't going with Bridgestones.

[URBAN LEGEND]

Originally Posted by Norm Peterson

Ummmm . . . no. You've clearly got some. That doesn't necessarily make it wrong (as long as the wheel is at least min-recommended width). Just bulged.

The amount of sidewall out past the outer face of the wheel's flange is 'bulge' and represents at least that much further the tire will distort in a corner or 'bend' to accommodate bumps. Wheel widths narrower than 'measuring width' for the tire size mounted on them are in fact slightly 'squeezed' or 'pinched' fitments.




Not nearly as much as this ↓↓↓




But more than this ↓↓↓ , which is still bulged a little (measuring wheel width fitment).




You have to get out near maximum-recommended width fitments before the bulge completely disappears. Yes, this is a slightly stretched fitment (actual rim wider than measuring).




Norm

Agreed. Especially the yellow car.

[URBAN LEGEND]

[QUOTE=TonyNDeb;9817110]

Originally Posted by URBAN LEGEND

But I wasn't going with Bridgestones.

MPSS runs very wide. I've been an MPSS guy since 2012 but the MPSS is too wide for the front. No way.

[Raven87]

Originally Posted by Norm Peterson

Ummmm . . . no. You've clearly got some. That doesn't necessarily make it wrong (as long as the wheel is at least min-recommended width). Just bulged.

The amount of sidewall out past the outer face of the wheel's flange is 'bulge' and represents at least that much further the tire will distort in a corner or 'bend' to accommodate bumps. Wheel widths narrower than 'measuring width' for the tire size mounted on them are in fact slightly 'squeezed' or 'pinched' fitments.


Norm

The Z/28's Trofeos come 'bulged' as you describe it so I can't imagine having some amount of material past the outer face is a major concern given the tire's profile height.

If it was, I would think GM would have used a different size tire altogether?

[pat_t]

on the subject of sidewall bulge, has anyone tried to fit a 325 Trofeo R to the front 11" rim?

[Norm Peterson]

Originally Posted by Raven87

The Z/28's Trofeos come 'bulged' as you describe it so I can't imagine having some amount of material past the outer face is a major concern given the tire's profile height.

If it was, I would think GM would have used a different size tire altogether?

It's not the 'fail' side of a pass-fail situation to have some 'bulge' (even though the word 'bulge' does carry mildly negative connotation). Though it is a visual indication that something has been left on the table if you're seriously into really hard cornering.

GM may well have decided for regular production to leave a little more 'progression' in the breakaway characteristics for this extremely capable car. If they're going to spec R-comp tires for a street-drivable car at all, fitting them to slightly narrower wheels than is possible in order to get a little more warning before they let go completely is something I'd fully expect the General to do.

At least one 305/30-19 appears to have been OK'ed by its mfr out to 12" wide wheels, and the Trofeo specs on Tire Rack's site don't even list a rim width range.


Norm

[pat_t]

Originally Posted by Norm Peterson

At least one 305/30-19 appears to have been OK'ed by its mfr out to 12" wide wheels, and the Trofeo specs on Tire Rack's site don't even list a rim width range.

Pirelli's own site says the 325/30/R19 is good for an 11J rim..

https://www.pirelli.com/tires/en-us/...pzero-trofeo-r

I just wonder if it will clear the front strut on the Z/28 without a wheel spacer..?

[AG1LE]

I have 325 MPS4S on all 4 corners (OE Z/28 wheels and Z/28 flares etc)

[TonyNDeb]

[QUOTE=URBAN LEGEND;9817216]

Originally Posted by TonyNDeb

MPSS runs very wide. I've been an MPSS guy since 2012 but the MPSS is too wide for the front. No way.

I did not know the MPSS were wide,, I just knew the Bridgestones were a little narrow. Until I read the specs, now I know about the MPSS. Either way,, the new shoes were delivered to the installer, and Tuesday I get them fitted.

[s.hammer]

The MPS4S do have a different shape than Trofeos, they seem to have a narrower tread but are wider at the sidewall area where the tire meets the rim, almost acting as a rim protector. I have a friend running 305s, 325s might fit the front depending on how much negative camber you run.