call me weird, but i dont understand tires at all

how do you tell the width?

whats the size mean? (sorta know)

i'm really confused and can use a refresher course on the matter

anybody care to offer?

 

245/50/16s. The first number is refers to the width. And the height of the tire is a ratio of the first number 50% I believe. The middle number I believe is the profile of the tire. And the last refers to what size rim it fits. Anyone feel free to correct me if I'm wrong.

 

I think tirerack.com has a complete breakdown.
Anyways..

P245/50ZR16

That would be:
P-passenger car (not always used)
245- section width, not overall width, measured in millimeters
50- aspect ratio, which is the percentage of the width that the sidewall height is. So, in this case, the sidewall height is 245*.5 For a 225/60 it would be 225*.6 Pretty simple.
Z- speed rating, theres a whole bunch. For the most part, the lower letters are low speed, higher are high speed. H and I think one other are exceptions. S and T speed ratings, just say no.
R- I think its obvious
16- I think thats obvious too

Truck tires are different (real truck tires anyway), they use what I think is the old tire coding, like my dads truck has Gsomethingx16.5. I never really looked into those codes before, wasnt interested.

 

deleted.. just made the thread longer

 

well lets take for an example a 255/50R15 tire. The first number "255" is going to be the measurement in mm from bead to bead (bead being where tire meets rim). The second number "50" is going to be the percentage of the first number "255", this gives the sidewall height. And of course the last number is the size (diameter) rim the tire will fit on which in this case is a 15 inch rim.

 

edit-double post

 

no. it is the measurement from sidewall to sidewall. the widest point on the tire. not the tread width. not bead to bead. that can change just by putting it on a narrow/wider rim. but the rest is correct.

 

you want to put money on that mrr23????

wreeeeeeeeeeeent!! Wrong!!

Bead to bead!! Meaning from the bead, up the sidewall, across the tread, down the other sidewall to the other bead. If you don't believe me go outside and measure yours. I worked at sears as a salesman and had training on this!!

 

well that's sears for you. i've been trained by michelin, bfgoodrich, firestone, and bridgestone since 1993. but just to make sure my memory hasn't gone a little foggy, i'll check tomorrow in the goodyear, dunlop and yokohama books at work. if i am wrong, i'll let you know.

 

bead to bead was the correct answer. once again someone with incorrect information correcting the right answer. thanx to the guys though that got it right. if what he's looking for is in inches though, he's going to have to go to the cataloges which are at the web sites or broshure's at the tire stores. i'm not sure though how this is a "refresher course" since it sounds like you never understood it the first time if there was a first time.

 

yeah thats sears for ya huh!!! LOL thanks Zippy!!

 

http://www.dunloptire.com/tiretech/W...a_sidewall.txt

read here my fellow enthusiasts.

 

http://www.goodyeartires.com/tiresch.../sidewall.html


and here.

 

http://www.pirelli.com/en_42/tyres/a...initions.jhtml


and here is one with a picture showing sidewall to sidewall. how much money was on this sears man?? (no4njunk). do i really need to keep proving my answer? no apology needed.

 

you obviously still don't get it. first of all if tires were measured by your method of explanation, all 255's would be the same width. the tire is measured from bead to bead, but not side to side. this number starts from one bead and follows the tire around to the other bead. the entire distance it takes to go from one side of the bead to the top of the tire and back to the other bead including sidewall is the distance. it is measured the on the inside of the tire. the 50 series (aspect ratio) would be 50% of the 255 mm is the sidewall. this is why a 255/70 would be taller than a 255/50 yet the is wider. the number is bead to bead including sidewall and top.

 

i obviously get it. my method of explanation is the one the tire manufacturer's give. not me. all 255's are the same SECTION width. so long as they are measured with the same rim width. the lower aspect ratio tires have a wider TREAD width versus the taller aspect ratio tires. you are correct on a 70 series tire being taller than a 50 series tire. but that was not where the disagreement was at. the section width, not aspect ratio, is where the disagreement lies. go up and read again. you are mixing up two measurements. i don't know everything, but i know where to find it. show me yours.

also section width changes with rim width. as per all the tire manufacturers listed above. every manufacturer even uses a different tread width for their series of tires. some manufacturers in 50 series tires use 75% tread width to section width. other use 80%-90% depending on what the manufacturer wants to make of their tire.

 

1)Sears man!! First off this is a very reliable source of information considering how many classes I took there. Where did you say you were trained??
2)Zippy is exactly right. I see where you are coming from mrr23 the point is different companies have different methods. I also know that pepboys uses the same method. Why are you saying you don't know everything but you know where to find it. From what you told us you have had a lot of training on this. or was all that . I have gotten my knowledge through experience not websites. Did you go out and measure??? Probably not.

 

if i was going to prove it with a diagram i'd use yours. plain and simple, the first number is bead to bottom of tread and sidewall to sidewall measurements added together. example given would be a 255/70 tire. it's sidewall would be 89.25mm tall and 76.5mm wide. all totalling the 255. a 255/50 tire would be 127.5 wide and 63.75 tall. the first number is section size total, not just section width from side to side.

 

yes sears man. you said you worked there. as far as where i was trained. read above on the references i made. the companies i worked for were Super Shops (michelin and bfgoodrich reps did the training) and firestone (obvious who trained there bridgestone/firestone). was refering to my foggy post. i can't remember everthing i was taught. but, i can grab books, go to websites, or call places to get the information. my knowledge is through experience also. dating back to 1993 as stated earlier. don't need to go out and measure. wouldn't be accurate because the rim is in the way. but, for the people who can't get the information about tires and how the numbers work, i listed websites for them to go to and read for themselves.

 

the diagram off of pirelli's website clearly shows the bead inside the sidewall measurement area. putting a 255mm (10.4") on a rim wider than 10.4" will at that point become a wider tire. the tread width won't change. but the section width will. that's why they also give you the rim width it was measured on. this is getting pointless. until you can show me where you are correct, i am. i have given 3 sites at which anyone can look at and see.

 

http://www.pirelli.com/en_42/tyres/a...YAAXFYKH5CSFFA



explaining section width being affected by rim width. and section height is from the bead to the highest point of the tread at a given tire pressure. so section height can be changed by tire pressure.

 

sidewall to sidewall. all 255's ARE the same width. if they werent, you could never reliably change tire brands. as for that argument, bead to tread to bead, my 245 is only 5 inches wide(instead of 9.8x). using a 50 series tire, half the overall measurement would be sidewall.

As such
245-sidewall to sidewall or treadwidth, in mm, pretty much interchangeable unless you oval out the tires (too big for rim) divide by 25.4 for inches

50-sidewall height, aspect ratio, bead to top of tread, i.e, a 255/50r16 is almost EXACTLY 26 inches tall on the rim and inflated, is Exactly ten inches+ 1 mm wide at the tread, and has a 16 inch rim diameter

r16- rim diameter, bead to bead.

sears boy, i can go measure my tire's tread if youd like, but its not 5 inches across, it's 9.6. and it is 26 inches tall. and it isnt a sears tire, its a bfgoodrich. if sears did their tires like that, id need a 610/25r16, just a thought.

 

thank you sir for your support. and to think bridgestone makes tires for sears.

 

Sears boy!!! Watch it unless you feel like starting a flame war!! Can you not do math. If your only getting 5 inches then you have a serious problem. Now listen up!! FROM 1 BEAD MEASURE UP THE SIDEWALL ACROSS THE TREAD ALLLLLLL THE WAY OVER TO THE OTHER BEAD. 5 inches huh!! Wow. BTW try measuring the cross section width on different tires and they will be different.

why don't you go and measure your tires and then come prove me wrong.

when did I ever say bridgestone made tires for sears??? Thats right I didn't. But actually they did used to. They were called the potenza.

 

don't need to. already gave 3 websites proving us right. (mrr23 and silverstreakII). you never said bridgestone did. i did. in reference to the fact bridgestone taught me. and you would think they would teach other dealers. and not the potenza. the dueler apt and the craftsman tire.

 

no they currently sell the Apt for trucks but they used to sell a passenger tire which was the potenza. when did I say they would teach other dealers?? Quit putting words in my mouth. Why are you so afraid to go measure your tire. It will take 5 seconds to do!!

 

just to try and help no4njunk out, i went and measured my 225/60-15. from bead to tread 4.5". tread width 8.25" so the total is 17.25" or converted to millimeters, 422.625mm. now 225mm is 9.183". now go out and measure your tires no4njunk. it looks like it doesn't add up to me. the numbers don't match. but if you look real close the tread width of 8.25" almost comes to 9.183". so if i was to get a caliper and measure sidewall to sidewall i bet it would be right at 9.183". but, of course your going to come back and say my tape measure is wrong.

 

show me where i put the words in your mouth. again i said it, and i admit it. well, you are probably right on the potenza tire. they have quite a few versions of the potenza. and i just did go out and measure my tire. you're not winning here.

 

I wouldn't say that. I stand corrected!! I know when I'm wrong and I'll just have to take this as a lesson. I'm suprised that sears gave me a book that says that in it (I'll scan the pic from the book as soon as I can). Its been about 3 months since I was laid off so I'm getting rusty. Well it was fun anyway. Kinda sucks how zippy bailed out!! Oh well.

Thanks,
Brian

 

Wow, I was wondering why there were so many posts on this subject. Let's get Vader in here to clear some things up, huh. Nevermind, it was cleared up while I was posting this.

 

Dear NO4NJUNK, please stop, you are wrong. You are doing nothing to help anyone on this board. If you don't know what you are talking about please keep your mouth shut.
If you would like for me to show you the error of you way please feel free to e-mail me at FaulknerRob
Thanks

 

no problem. i believe you about the book. a long time ago (1994) someone told me about the bead to bead measurement too. i belived him until someone proved otherwise. i commend you for sticking to your guns. i would do the same thing until i was proven wrong. it was a good battle.

 

don't need to. no4njunk has conceded. he was a good opponent. reminds me of myself. fight until the end.

 

Wow dude chill out. Can you not see what I just posted!! I'm wrong ok. I was doing it for arguments sake...no harm done.

nothing to help the board huh!! go check out some of my 2xx posts and i'll check out your 51. Then we'll see who's helping the board.

 

yeah leave him alone. he was only standing up for what he believed in. ws6 posted while you were posting. so it was just timing on the posts.

 

Ok. I understand. Time for me to go to bed.

 

me too same time zone as you 1:18a.m.

 

Sorry we posted at the same time. I did not mean to come across as a n a**hole but it bothers me when a question turns into a fight. I just hope that the person who asked the question got the correct answer. If not E-mail me and I will try to help. I have a few books here with the info in them but no scanner.

 

understandable. We weren't fighting but simply arguing. It wasn't meant to be derogatory in any way. This is how adults handle situations...by arguing a point and not flaming. Yeah I kinda feel bad now. I hope he got all the answers but mine I think i'll pm him. later