Contour Enthusiasts Group Archives Forums Modifications Wheels & Tires Which is the better route to take?

http://www.tiresafety.com/size_class/size_nav.htm#pmetric

Please read this page, all of it.

Then redo your math.

Then comeback.

I'll play along, since it's Saturday night and I'm staring at the pager so it doesn't go off.

215/55-16

Facts The Section width of the tire is 215mm, the wheel diameter is 16" and the aspect ratio is 55%. That means, the section height of the tire (or the measurement from the bead to the tread surface) is 55% of the section width.

Note to all following along, the section width is NOT the tread width, but rather the width of the tire at it's widest point. I don't believe this includes any raised lettering, but rather the widest sidewall to sidewall measurement.

So, using the FACT that one inch is 25.4mm we get the diameter of the wheel is the product of 16 and 25.4 or 406.4mm

Using the what we know about the section height listed above, the section height of a 215/55 tire is 225*0.55 = 118.25mm. We also know that you have to multiply this number by two, because each tire, properly inflated, has this section height above and below the wheel.

So the height of a 215/55-16 is the sum of 406.4mm + 118.25mm + 118.25mm or 642.9 mm or in inches, 25.31" in diameter.

Now for the 225/50, since we are mounting on the same wheel, the wheel is still 406.4mm

However, our tire has a section height of 225mm*0.50=
112.5mm.

You can already see that 112.5mm roughly 6mm shorter than 118.25. If you are really anal about this, the difference is 5.75mm

So our properly mounted and inflated 225/50-16 tire will have a diameter of 406.4+112.5+112.5= 631.4mm or 24.85"

Just under 1/2 shorter than the 215/55.

So now that I've done the math, why don't you show us pictures of the two tires in question (same make and model of tire, in the two sizes you list, with a fully visible yard stick or some other measuring device, so we can see you demonstrate your point.

It's only fair, right, I had to show my work, so you show yours, LOL.

TB

And if my work isn't good enough, let's see what Bridgestone/Firestone get when they do the same math.

http://www.bridgestonetire.com/dpp/sizespecs.asp?passproductid=227

215/55-16
Overall Tire Diameter = 25.3"
Static Load Radius = 11.6"

225/50-16
Overall Tire Diameter = 24.9"
Static Load Radius = 11.5"

Seems Bridgestone/Firestone agrees with me on this one.

Remember I got 25.31 (so they rounded to 25.3") for the 215/55 and I got 24.85 (and they rounded up to 24.9") for the 225/50.

So now you have to convince the world that both me and Bridgestone/Firestone don't know how to measure tires.

And I'm sure I can find another tire maker and look at his products as well, and find nearly the same numbers.

http://www.goodyeartires.com/catalog/products/EAGLERSASize.html

FWIW,

TB

Originally posted by pancho1181:

---

Believe what you can man, but if you think TireRack is selling you 225's because "they are better fit and not because they are making more money off of them" then you are mistaken.

---

TireRack isn't selling me tires. They never were. They just happen to be telling me the truth in this case(well, if Luke counts as TireRack). Well, now that you mention it, maybe I will buy from TireRack

Originally posted by pancho1181:

---

225 is taller, I don't know how nmany times I have to say this. I measured a Dunlop SP-5000, a 225 and a 215/55, and the 225 is taller, hence the comment "I don't see why anybody would have any problems with a 215/55 that they wouldn't have with 225/50" because the 225's are taller, hence why the tires rub.

---

So, once again, you're saying that the 225/50/16 tire is the only tire available that doesn't follow the measurement specifications listed on the sidewall.

And I checked the page you recommended and I read it completely. I did the measurements according to that page and it shows that the 215 should be taller than the 225. However, as you say, the 225 is the exception to the rule.

Originally posted by pancho1181:

---

I don't know any simpler English or I would post using it, 225 is TALLER, 215/55/16 is a good fit. I don't see Luke saying anything about "from experience" You can throw all the numbers you want Luke, you will still be wrong, and I can write your district mannager and make you see, thru court, I AM RIGHT. DO NOT MISSINFORM YOUR CUSTOMERS OR YOU WILL BE PUBLICLY EMBARRASED. Use all the sweet talk you want that has helped you suck money out of loyal Contour/Mystique owners, but you ain't telling the truth.
Do you know false advertising can get your company in very deep sh*t?

---

I don't think that would be false advertising as every single tire definition page says that a 215 should be taller.

Originally posted by pancho1181:

---

Stop the "I have 20 years of experience talk" and start telling me some real facts about the tire I am recommending against the size 225 that you seem to like so much.

---

You don't like Luke very much, do you? The 225 tire size came from me, not Luke. Read the very first post of this thread (I started it). It asks between 225's and 205's. I wouldn't consider a 215/55 as you're the only guy recommending it. And weren't your the guy that started the "experience talk".

You know what, you might be right. But don't attack Luke. Attack the tire industry for this dreadful conspiracy they must have going. I can see them now in their boardrooms.

"But sir, if we mislead the public on the 225/50 tire specifications versus it's actual measurements, we can then insert an experienced tireman...we'll call him "Pancho" and he can bring down TireRack once and for all. It's all too easy."

Oh yeah, Pancho, I found this gem earlier in the thread.

Originally posted by pancho1181:

---

Take a 215/55/16 and put it next to a 225/50/16.

THEY ARE THE SAME HEIGHT.

---

Now, wait a minute, I thought your whole argument was that the 225 was taller. Make up your mind!

Pancho,

You have not proved your "facts". A few people have proven 215/55R16 is supposed to be and by manufacturer measurements is taller. We have done this by math, by the definition of tire sizes. You are the only one that believes 225/50 is taller. Since you have access to the two tire sizes in the same model, please show us a picture to prove it as Tony suggested. BTW, 225/55 is taller than 215/55 and 225/50. Just in case anyone has confused you.

You just don't get it. It isn't because Luke, or Tirerack, or some book said something so we hold it as gospel. We relied on many sources that all point to the same thing. If for some reason all theouse sources are wrong, I'd like to be the first to know.

In reply to:

---

I don't like when people base their facts on what other people say about the tires they put on their vehicle.

---

But you are asking us to do the same with you? Why should we trust you? Just because you install tires every day on many cars? Like I told you in a PM, I have met many tire installers and salespeople that have not known very much in terms of what products they are actually putting on their vehicles. You are just another.

Did you even pay attention to what I said about only SVT Contours having 16" OEM rims? All others are 15" wheels with 205/60R15 tires. I wonder if you have ever installed tires on an SVT Contour. More likely that you use 215/55R15 on OEM 15" Contours & Mystiques. How many customers with aftermarket 16" rims come into your shop on a yearly basis and how many SVT Contours?

In reply to:

---

I don't see Luke saying anything about "from experience" You can throw all the numbers you want Luke, you will still be wrong, and I can write your district mannager and make you see, thru court, I AM RIGHT. DO NOT MISSINFORM YOUR CUSTOMERS OR YOU WILL BE PUBLICLY EMBARRASED. Use all the sweet talk you want that has helped you suck money out of loyal Contour/Mystique owners, but you ain't telling the truth.

---

Hmm, who is the one that is publicly embarrased? You are doing a fine job of it yourself.

BTW, if you'd like to keep sending my those lovely private messages, I can start making them public and some people might find them humorous. I do. Quit sending me messages with excessive use of profanity and threats of personal injury! I'm sure they would be enough to ban you if I really cared enough. But I don't. You have a lot of experience that I'm sure many people would benefit from. Just don't get so upset with people you don't even know over something as little as a marginal tires size difference.

Aaron

Hmmm, doing the conversion everybody is using I get this:

225/50/16 = 4.43"

215/55/16 = 4.65"

Hmmm, don't worry, pics are comming.

BTW, tires in question here are Dunlop SP-5000's and Dunlop SP-A2's.

Originally posted by pancho1181:

---

Hmmm, doing the conversion everybody is using I get this:

225/50/16 = 4.43"

215/55/16 = 4.65"

Hmmm, don't worry, pics are comming.

BTW, tires in question here are Dunlop SP-5000's and Dunlop SP-A2's.

---

Yup, very same numbers I get.

I do hope you are planning to compare the identical tires, IE two SP5K's and two SP-A2's. Plus, if you are relying on Dunlops website, I suspect you are victim of a webmaster who rounded every number to the nearest whole number. Either that, or they went to a lot of trouble to ensure every tire is exactly x" high with no tenths.

However, I don't doubt that with some tire makers, due to slight differences in production tolerances, that you could get a 215/55-16 that closer in size to a 225/50-16. But, I suspect that will be the exception rather than the rule.

And that is the point we are all making.

We've all be arguing about roughly 0.5".

FWIW

TB

Originally posted by pancho1181:

---

Hmmm, doing the conversion everybody is using I get this:

225/50/16 = 4.43"

215/55/16 = 4.65"

Hmmm, don't worry, pics are comming.

BTW, tires in question here are Dunlop SP-5000's and Dunlop SP-A2's.

---

Your math agrees with everybody except you ....
now that's funny

Originally posted by Luke@tirerack:

---

Your math agrees with everybody except you ....
now that's funny

---

yes it is funny