Why the f00k does my sidewall keep bubbling?

[Jedidiah]

Nitto NT555's are your answer.. they stretch great, good wear and are quality made... wet traction is the only issue i have heard, but that hasn't been the case with me.

[Tuck&Poke]

Man everyone has prbs with 452s but I have not had any prbs with them.

x2, ive run two whole sets, with stretch, no issues, wore em down to the wires

one set was 215/40 on an 8.5 and 235/40 on a 10, the other set was a 215/45 on a 9.5 and 235/40 on an 11

[Presns3]

ive had a sh1t load of falken 452s bubble on me... 215/35/19s

[geoffafa]

Nitto NT555's are your answer.. they stretch great, good wear and are quality made... wet traction is the only issue i have heard, but that hasn't been the case with me.

hmm a friend is running those on his CHs. where did you buy yours from?

[Presns3]

Falkens FTMFL
look what happened to my Falkens on my E46 today on the freeway
sighh....

http://img696.imageshack.us/g/dsc0158vq.jpg/

[Tuck&Poke]

whoa...

[cheez80]

you are using falkens.
i use hte shit out of some nankang NS2s

nankang +1

[IIXtremeHansen]

damn thats horrible^^

[fatboy.yoshi]

Nitto NT555's are your answer.. they stretch great, good wear and are quality made... wet traction is the only issue i have heard, but that hasn't been the case with me.

word im rocking nt555's on my fronts and they stretch great...and i have not had any wet traction issues either...im running kumho spt's rears no probs either...and the stretch on both are great

[Geoff.T]

215/40 is always going to be 215/40, not a 205/40. The reason why 512's LOOK smaller is the sidewall construction. Mathematically, they are the same.

Not true...

a Falken 512 in a 215/40 section width is 8.5in wide while the same size tire in a RT615 is 8.7in wide

Check for yourself under each tires specs and sizes.

http://www.falkentire.com/

All tire companies section widths vary even though the labeled sizes are the same.

[simple g50]

nankang +1

+2. Nankang stretches nice and has a reinforced sidewall.

[Rally]

All tire companies section widths vary even though the labeled sizes are the same.

True story. The autocross guys love finding tires that underestimate the labeled sizes so they can get as much section width as possible while still staying within the designated class rules. A 205 doesn't necessarily mean it's absolutely 205 wide...some are wider some are skinnier.

[Han]

Right, but section widths are not used to calculate rolling diameters. The overall width is, hence the 205/215/225/etc designation.

Section Width

A tire's section width (also called "cross section width") is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point. This measurement is made without any load placed upon the tire and after the tire has been properly mounted on its industry assigned measuring rim and has been inflated and reset to its test pressure after 24 hours.

http://www.tirerack.com/tires/tiretech/tirespecskey.jsp

AKA: Why I said it's a sidewall design, not actual width (IE: 225) because that stays constant.

[Geoff.T]

Right, but section widths are not used to calculate rolling diameters. The overall width is, hence the 205/215/225/etc designation.

http://www.tirerack.com/tires/tiretech/tirespecskey.jsp

AKA: Why I said it's a sidewall design, not actual width (IE: 225) because that stays constant.

Technically no.

40 series is means the side wall is 40% of the width of the tire. Since we established that the section width can vary then so does the side wall height.

My 255/40 Toyo RA1s have a greater rolling diameter than the 255/40 Toyo T1Rs I use to have. Its clearly visible because the T1Rs sat about a half inch shorter than the RA1s

[Han]

Technically no.

40 series is means the side wall is 40% of the width of the tire. Since we established that the section width can vary then so does the side wall height.

My 255/40 Toyo RA1s have a greater rolling diameter than the 255/40 Toyo T1Rs I use to have. Its clearly visible because the T1Rs sat about a half inch shorter than the RA1s

Yes, I understand that. However, 40% of 255 is always going to be 102mm.

Width x Aspect Ratio = Section Height
Section Height x 2 = Combined Section Height
Combined Section Height + Wheel Diameter = Tire Diameter

Width x Aspect Ratio = Section Height
Section Height x 2 = Combined Section Height
Combined Section Height + Wheel Diameter = Tire Diameter

Example: 185/60R14 85H or 185/60HR14

185mm x .60=111mm
111mm x 2=222mm
222mm + 355.6mm(14")= 577.6mm or 22.74"

The first number is the width of the tire in millimeters, measured from sidewall to sidewall. To convert to inches, divide by 25.4 In the example above, the width is 185mm or 7.28".

The second number is the aspect ratio. This is a ratio of sidewall height to width. In the example above, the tire is 7.28" wide, multiply that by the aspect ratio to find the height of one sidewall. In this case, 185x0.60=111mm or 7.28"x0.60=4.36".

The last number is the diameter of the wheel in inches.

To figure the outside diameter of a tire, take the sidewall height and multiply by 2,(remember that the diameter is made up of 2 sidewalls, the one above the wheel, and the one below the wheel) and add the diameter of the wheel to get your answer.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=7

255 x .4 = 102mm = Section Height
102 x 2 = 204mm = Combined section Height
204mm + 431.8 (17 x 25.4) = 635.8 / 25.4 = 25.0314 inch = Tire Diameter

Falken 512's list a 255/40/17 as a 25.2 Diameter. (A tire that people consider "small")
Falken 452's list a 255/40/17 as a 25.0 Diameter. (A tire that people consider "small")
Falken Azenis RT-615 list a 255/40/17 as a 25.0 Diameter (A tire that people consider "correct"/"big")

Your examples:
Toyo RA1 lists a 255/40/17 as 25.0 Diameter. http://toyotires.com/tire/pattern/proxes-ra1
Toyo TR1 lists a 255/40/17 as a 25.0 Diameter. http://toyotires.com/tire/pattern/proxes-t1r


Those are all measured on a 9" wide wheel by Falken and Toyo.

That's a variance of +/- .2" (.1" top and .1" bottom). That's acceptable, but I cannot see any tire have a +/- .5" variance in measurement... Unless if your measurements are in a completely controlled environment and with static variables and controls, I do not see a logical reason to disprove the tire manufacturer's own findings.

Again, it's all visual differences. Math and numbers don't change.