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I'm looking to buy some 18" Enkei RP03 rims I'm debating getting the 7.5" with 48mm offset which should be fine or the 8" wide rim with 45 offset, and what would be the best tire size for each, pretyt specific, I just started working at a tire place this week and will be purchasing wheels in a in the next few weeks and rimsby may, I only ask because I can get a really really good deal on Kumho Ecsta MX at wholesale and the wholesale prise is on sale lol, so I want to buy the tires now and the rims to slap em on later.
 

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I'm looking to buy some 18" Enkei RP03 rims I'm debating getting the 7.5" with 48mm offset which should be fine or the 8" wide rim with 45 offset, and what would be the best tire size for each, pretyt specific, I just started working at a tire place this week and will be purchasing wheels in a in the next few weeks and rimsby may, I only ask because I can get a really really good deal on Kumho Ecsta MX at wholesale and the wholesale prise is on sale lol, so I want to buy the tires now and the rims to slap em on later.
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From what TG Posted:

18"

215/45R18 7.0"-8.0" 32 psi
225/40R18 7.5"-9.0" 38 psi
225/45R18 7.0"-8.5" 32 psi
235/40R18 8.0"-9.5" 33 psi
245/40R18 8.0"-9.5" 32 psi

If you want to run a 235 series tire, you will need the 8 inch wide rim. Other than that, it depends on what tire you want to run and its all about preference. Also, if you plan on rolling your fenders completely, you shouldnt have fitament problems with either rim.
 

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Can someone tell me, I have 17" MOMO tuner wheels but i have no idea what the offset is. The stock tires are on them now and I'm wondering if I can get away with a 225/ wheel, and what aspect i should use?

P.S. I know NOTHING, if you cant tell
 

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Can someone tell me, I have 17" MOMO tuner wheels but i have no idea what the offset is. The stock tires are on them now and I'm wondering if I can get away with a 225/ wheel, and what aspect i should use?

P.S. I know NOTHING, if you cant tell
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You should really look up the MOMO website and see if you can find your wheels and see what the offset might be. Without knowing anything AND TOTALLY GUESSING, If you have your stock wheels on and you are fine, as long as your 17" momo wheels have a 7 inch wide rim, you should be able to eyeball if you can run a 225 series tire. Look at the tire and picture how it will go with your suspension fully compressed. As long as it isnt dead close, you SHOULD be able to put a 225/45/17 on there.

Again, this isnt 100% fact because I dont know your offset and rim width, Im just making an educated assumption based on 17x7 being the standard rim size and since going from a 215/50/17 to a 225/45/17 is only a very minor change.
 

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I have a set of 17x7.5 rims w/ +48 offset. Should I be able to use a 225/50 tire without rolling? I don't plan on lowering. I haven't seen anyone else with this particular setup. Thanx.
 

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I was wondering if I can fit a 235/45 tire on a 17x8 ET48 rim. I'm going to try them next after my advan neovas wear out...lol. those tires look like r-comps..haha
 

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Discussion Starter #47
I was wondering if I can fit a 235/45 tire on a 17x8 ET48 rim. I'm going to try them next after my advan neovas wear out...lol. those tires look like r-comps..haha
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That should work (at least the tire + rim combo is okay). You'll probably have to roll fenders.

I have a set of 17x7.5 rims w/ +48 offset. Should I be able to use a 225/50 tire without rolling? I don't plan on lowering. I haven't seen anyone else with this particular setup. Thanx.
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Should be okay, but don't hold me to that! :p
 

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From Nitto's own website:

225/30ZR20 85W Overall diameter: 25.35 inches

This tire is the right height, but with a load index of only 85, how can you say that this tire has enough load capacity? For the umpteenth time, the Mazda6 REQUIRES A 91 LOAD INDEX MINIMUM! (Damn, I just burst a blood vessel!)

But hey, what do I know? Obviously nothing. :sarc:
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Technically speaking, a 225/30/20 Pirelli P-Zero Nero has an overall rolling diameter of 25.5". That's only .1" off from the stock 25.6" O.D. on my MS6's 215/45/18's. That's about as good of a match as you can get in the tire world. +/- .2" is the recommend tolerance but +/- .4" is a very common occurance. 20's do not pose a problem, fitment wise, if the proper offset is achieved with the right wheel width. Shoulder profile varies from tire to tire as well which may help or hinder fender and control arm clearance.

The load rating on the same 225/30/20 is an 85, equivalent to 1235lbs per tire. Muultiply that by 4 tires gives you a total load rating of 4940lbs.

A 6i weighs about 3050lbs with my MS6 weighing in at 3600lbs. So on my heavier MS6 that leaves 1340 lbs for passengers and cargo.

Four extremely large 250lb adults would still leave you with room for 140lbs of cargo in the trunk or an average female passenger in the middle rear seat. Realistically speaking I only weigh 170lbs which leaves me 1170lbs for cargo and passengers. Remember, you have an additional 200-300lbs of load capacity if you're driving a non-turbo 4cyl or V6.

Plus, tire manufacturers conservatively buffer the load rating on a tire for safety reasons so they can actually handle more than they are rated for.

I personally wouldn't do a 20 but that's not to say that it can't be done successfully or safely. Heat causes tires to fail, so as long as you're not exceeding the load rating of all four tires or the speed rating for more than 20 minutes, such as towing a 2000lb boat at 320km/h for a 4 hour trip to Montreal, you should be fine. :D I'll bet you any money anyone who would do 20's probably rolls single or tandem most of the time and doesn't find himself in a car full of people with tons of cargo in the back.
 

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Discussion Starter #49
dj petey, I don't know where you get your information, but you're way off base. First of all, we don't use curb weight to determine load rating of a tire to a specific vehicle. We use GVWR (Gross Vehicle Weight Rating). That means the tires must be capable of handling more load than the springs/suspension. GVWR is always much higher than curb weight.

Also, your reasoning is flawed because you're only taking into account static weight. You're not factoring in transfer loading which occurs while the vehicle is in motion. Under acceleration, braking and turning load shifts to the rear, front, left and right. When performing those maneuvers aggressively, the transfer loading increases. It's even more so when passengers and cargo are on board. It may not last long, but under those stress/load conditions, the tires must be able to handle that amount of load which is much higher than what you're talking about. The load is not distributed evenly.

The "reserve load" you refer to is not that the tires have more load than what the sidewall says, it's that we reduce the number on the sidewall by 10%. If that number still exceeds the GVWR, then you have a safely load rated tire for that vehicle. So, the 1235 on your 20s must be reduced to 1112. The GVWR is 4491 lbs. for the wagon (the heaviest model in the range). 1112 x 4 = 4448. Not enough. Plus, you'd have to run them at 50 psi just to get this amount of load. How many people do you know are going to drive around with their tires pumped to 50 psi all the time? Not going to happen. This is why I keep insisting that you maintain a load index of 91 or greater.
 

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Should I trust a dealer's "what fits?" data on their homepages?

I'm going to buy wheels via internet because in my city (monterrey, mexico) we don't have a decent wheel dealer so i've been carefully reading all the info in the forums and on the web and mostly interested in pics of wheel mods on mazdas :yesnod: .

(btw... i own a 6i and so far, i'm particularly interested in König's Theory 18").
 

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PLEASE NOTE!!!! DUE TO LEGALITIES THAT WENT INTO EFFECT SEPTEMBER 1, 2005, THE INFORMATION CONTAINED BELOW IS FOR MAZDA 6 MODEL YEARS 2003-2005!!! FOR INFORMATION REGARDING MODEL YEAR 2006 AND UP, PLEASE CONTACT MAZDA USA OR YOUR LOCAL MAZDA DEALER!!!!
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What legalities went into effect back then?... are these critial for choosing wheel/tire combo?
my 6i is 2006. Just got it 2 weeks ago.
 

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Discussion Starter #52
What legalities went into effect back then?... are these critial for choosing wheel/tire combo?
my 6i is 2006. Just got it 2 weeks ago.
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This was a "cover my butt" disclaimer due to the TREAD Act, which certain portions went into effect last September. I was advised by higher-ups at Toyo not to make recommendations for ANY vehicle model year '06 and up. There were no changes made in tire sizes from model year '05 to '06, so you can make reasonable assumptions on what fits the '06 model. ;)

If we decide to issue a fitment guide for '06 cars, I will remove the disclaimer.
 

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Wrong section... Sorry
 

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Hey Guys, I've done a lot of searching and reading on the tire/wheel size topics, so I'd appreciate not getting any "do your search" responses.

I'm in Japan and am driving a JDM 2005 Atenza 23S (5dr. Sport) that came with Mazda-spec 215/45 R17's (total diameter 24.62in.). Intersetingly Mazda Japan says that the speedo and odo are calibrated to this tire/wheel size.

Given that the roads in Shiga Japan absolutely suck, I'm thinking of minus sizing to 215/55 R16's (total diameter 25.31 in, 1% bigger than the stock). I have not selected a wheel but it looks like a 55mm offset would work.

I've contacted Mazda Japan and their response was non-commital. Their legally Japan-registered (tested/recommended) tire sizes are 205/55R16s or 195/65R15's which are narrower and smaller in diameter, not something I want (I'd rather have larger wheel diameter).

Comments? Anyone have 215/55R16's?? I've searched hi and low but noone here in this forum seems to have this size, and I've checked other forums as well. Thanks in advance!!

If you wanna see pics of my car they are here:
http://www.msprotege.com/forum/showthread....1142&page=2

(Edit)
p.s. Other than my Mazdaspeed seat, absolutely no mods (i.e. Suspension is original eq.).
 

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I'm in Japan and am driving a JDM 2005 Atenza 23S (5dr. Sport) that came with Mazda-spec 215/45 R17's (total diameter 24.62in.). Intersetingly Mazda Japan says that the speedo and odo are calibrated to this tire/wheel size.
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Those Dunlop SPs you currently run have an 87 load rating. If those are stock from Mazda's Hiroshima assembly line, that spec makes very interesting data point for the sporadic question here about what is the minimum load rating for the Mazda6.

Given that the roads in Shiga Japan absolutely suck,
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Sonna ni hidoi no? Dono hen? I haven't seen roads that were "absolutely suck" bad in the Kanto area for years. (But then there are not all that many places you can go more than about 50 km/hr either. :drive: Is this a jar-the-tailbone issue because you have the Mazdaspeed seat, or is it a worry about tire/rim damage from the low profile?

I'm thinking of minus sizing to 215/55 R16's (total diameter 25.31 in, 1% bigger than the stock).
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Have you measured any mounted on a wheel, or are you going on the basis of a tire calculator? Because of the granularity of tire size designations, any given tire, when mounted, could easily be more than that 1% larger than the calculator shows (exascerbating the problem) or more than 1% smaller (giving you a baby bear "just right" for your application). Most of the 215/55-16 tires have a load rating of 93, whichh would be a nice bonus.

I have not selected a wheel but it looks like a 55mm offset would work.
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Assuming that the Japanese-spec Atenza comes stock with the same 60mm offset 17x7 wheels that the US-spec Mazda6 does, you should be o.k. with a tire that is just 10mm wider in section width. The problem, if any, would be rubbing the fender in the rear, but the dimensions would be so close, it would be a problem certainly remediable by rolling the fender.

I've contacted Mazda Japan and their response was non-commital. Their legally Japan-registered (tested/recommended) tire sizes are 205/55R16s or 195/65R15's which are narrower and smaller in diameter, not something I want (I'd rather have larger wheel diameter).

Comments?
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If Mazda Japan approves 205/55-16, then it is very likely that a 215/55-16 will work just fine. I have yet to see the instance where going a mere 10mm wider from factory spec within the same aspect ratio caused a problem. (Of course, there is always a first time :).)

Can you get Goodyear Eagle GS-D3 tires there? In the U.S., at least, they are available in the 215/55-16 size. Nice tire.
 

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Posttosh, thanks for your response. Interesting info in some of your questions. My responses are interspersed:

Those Dunlop SPs you currently run have an 87 load rating. If those are stock from Mazda's Hiroshima assembly line, that spec makes very interesting data point for the sporadic question here about what is the minomum load rating for the Mazda6.
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Yes, the OEM tires are Dunlop SP Sport 8090's 215/45R17 87W's. I've seen them on TireRack as OEM tires for the RX8's in the U.S.
FYI, for the 205/55R16's Mazda Japan recommended 89V's and for the 195/65R15, 91H's.


Sonna ni hidoi no? Dono hen? I haven't seen roads that were "absolutely suck" bad in the Kanto area for years. (But then there are not all that many places you can go more than about 50 km/hr either. :drive: Is this a jar-the-tailbone issue because you have the Mazdaspeed seat, or is it a worry about tire/rim damage from the low profile?
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The roads are crap. It gets just cold enough in the winter here in Shiga for water to freeze and bingo!! Potholes galore, and Shiga doesn't bother repaving. They just fill and fill and fill and fill etc. I think you get the idea.... My wife sits in the passenger side and the suspension on the Atenza, although not hard, is still tight enough to make it bumpy. I'd like to soften the ride a bit.

Have you measured any mounted on a wheel, or are you going on the basis of a tire calculator? Because of the granularity of tire size designations, any given tire, when mounted, could easily be more than that 1% larger than the calculator shows (exascerbating the problem) or more than 1% smaller (giving you a baby bear "just right" for your application). Most of the 215/55-16 tires have a load rating of 93, whichh would be a nice bonus.
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I just calculated as follows: [(Tire Width x (Aspect Ration/100) x 2) / 25.4] + Rim Diameter
So tire manufacturers are like clothing makers. Size 10 shoes may not really be size 10, eh? hmm...

Assuming that the Japanese-spec Atenza comes stock with the same 60mm offset 17x7 wheels that the US-spec Mazda6 does, you should be o.k. with a tire that is just 10mm wider in section width. The problem, if any, would be rubbing the fender in the rear, but the dimensions would be so close, it would be a problem certainly remediable by rolling the fender.
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The rim offset of the 16, 17 and 18 in. JDM wheels for the 2005 Atenza 2.3S's for are all 55mm. For the 195/65R15, offset is 50mm. For the 15 and 16 in. wheels, PCD (whatever that is) is 114.3 and hub diameter is 67in.

As for rolling the fender, that might be illegal in Japan.... I know for a fact that tires that rub or extend out from the body are illegal, but I'm not sure if rolling the fender to dodge that is legal or not. At this point rolling anything is not in my options bag.

If Mazda Japan approves 205/55-16, then it is very likely that a 215/55-16 will work just fine. I have yet to see the instance where going a mere 10mm wider from factory spec within the same aspect ratio caused a problem. (Of course, there is always a first time :).)
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Well it seems the offset is different between the US and Japan. Very interesting. I'd have to study up a bit more on offsets to figure this out....

Can you get Goodyear Eagle GS-D3 tires there? In the U.S., at least, they are available in the 215/55-16 size. Nice tire.
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Yes, they are available. But I'm interested in getting All Season tires which are not available here in Japan (collusion by tire companies here deceiving the populace for the need to have snow tires - new cars only come with summer tires). See, if I knew I could get all season tires here in Japan, I'd go to the local shop and have them test the fitment, but I can't. Hence all this research so I can buy it from like TireRack or some other store that will ship overseas. Isn't this crazy? If I had a garage and space to swap my tire sets, I'd have 2 sets but here in Japan? hahahahaha.

Well, does this help in determining whether 215/55R16's will fit on JDM Atenza Sport 23S? Again, folks, thanks for any input...

(Edit)
BTW the 2005 Atenza 23Z version came with 215/45R18's so that's a full inch bigger in diameter compared with my 23S. If that fits, I don't see why a 215/55R16 won't fit, but Mazda may have made some adjustments for that car, including gear ratios. Soooo that's why I am asking, folks....

(Edit 2)
Sorry for these edits.... the real reason I want all seasons is that winter tires in Japan, unless you live up north where the roads are snow covered 80% of the time in the winter, don't make sense. Here where I live, it snows maybe 3 times a year (like 10 in. each time) and it melts in 3 days. Winter tires just for that don't make sense - cost of the tires, wheels and cost for storage, time to swap 'em etc. ain't worth it.... hence I accuse the tire companies (all of 'em) of a closed market and collusion in Japan.
 

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I just calculated as follows: [(Tire Width x (Aspect Ration/100) x 2) / 25.4] + Rim Diameter
So tire manufacturers are like clothing makers. Size 10 shoes may not really be size 10, eh? hmm...
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It is a little different. The word I used was "granularity." Section widths must end in -5, so a tire is specified as a 195, 205, 215 ... but no value in between. Aspect ratio is specified in multiples of 5: 65-series, 60-series, 55-series, etc., but no values in between. Now, in actuality, the size designation of a tire is determined after the tire is designed, and so a tire may "really" be a 207/53-16 tire, but the official size molded onto the side would be 205/55-16. A further factor is that the actual measurement of a tire is valid only if the tire is mounted on the specified measuring rim. Mount the tire on a narrower or a wider rim than the measuring rim, and the tire's dimensions will change. For instance, if you take a 225/45-17 tire that measures a true 225mm section width when on its measuring rim (usually 7.5") and squeeze that tire onto a stock 7" Mazda6 rim, after mounting, the actual section width will measure closer to 220mm.


As for rolling the fender, that might be illegal in Japan.... I know for a fact that tires that rub or extend out from the body are illegal, but I'm not sure if rolling the fender to dodge that is legal or not. At this point rolling anything is not in my options bag.
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The fender rolling is not for sticking out but for tucking in. :wavey: The front fenders come from the factory with the inside edge of the wheelwell neatly tucked in, but at the rear, on the inside of the fender, Mazda leaves the edge kind of raw. That raw edge can catch on the outside sidewall of the tire when the wheel goes over a bump. Fender rolling, invisible from the outside, just tucks in that raw edge. See the "Photographic Journey" here: http://mazda6tech.com/index.php?option=com...17&Itemid=1

I'm interested in getting All Season tires which are not available here in Japan (collusion by tire companies here deceiving the populace for the need to have snow tires - new cars only come with summer tires).
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:laugh: You probably do not realize that you addressed that to the biggest anti--"all season" tire fanatic on this board. I completely agree with and applaud the Japanese regulations. (Short summary: the same technology that makes an "all season" tire stick to snow also makes water adhere to the tread instead of being repelled from it as it is on "summer" tires -- and that, in turn, makes wet traction of "all season" tires crappy.) There are others here who believe that the Tooth Fairy has exempted them from the compromise built into every "all season" tire, and who get upset when I disagree with them.
 

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QUOTE(MadBiker @ Sep 9 2006, 12:34 AM) *

I'm in Japan and am driving a JDM 2005 Atenza 23S (5dr. Sport) that came with Mazda-spec 215/45 R17's (total diameter 24.62in.). Intersetingly Mazda Japan says that the speedo and odo are calibrated to this tire/wheel size.[/b]
Those Dunlop SPs you currently run have an 87 load rating. If those are stock from Mazda's Hiroshima assembly line, that spec makes very interesting data point for the sporadic question here about what is the minomum load rating for the Mazda6.

[/b]

Interesting discussion. especially because I myself (bieng a one-time design engineer for automotive bearings for the worlds largest bearing company) realize that there are umpteen different things that go into the selection of a product on top of the the load rating itself. In all of the cases, the product selectors will select a product from a range of products that meets/exceeds the needed load ratings AND that meets their aesthetic design requirements and few more non-technical aspects related to vendor-customer relations.

So like I said earlier, unless a product manager from Mazda who was responsible for the tire selection on the Mazda6 speaks, we are at this time simply trying to interpret the way we see it. is 91H/v safe. Absolutel yes. Is it the bare minumum? it is safe to assume it is. But is that the reality? ? ?
 

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Discussion Starter #59
There are others here who believe that the Tooth Fairy has exempted them from the compromise built into every "all season" tire, and who get upset when I disagree with them.
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And there are others on this board who think they know more than they do. :thefing:

You want to pick a fight, posttosh, fine. You seem obsessed with proving me wrong to the point you will make unprovoked snide comments toward me. You are pathetic.

MadBiker, you really want to take advice from this guy?
 

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It is a little different. The word I used was "granularity." Section widths must end in -5, so a tire is specified as a 195, 205, 215 ... but no value in between. Aspect ratio is specified in multiples of 5: 65-series, 60-series, 55-series, etc., but no values in between. Now, in actuality, the size designation of a tire is determined after the tire is designed, and so a tire may "really" be a 207/53-16 tire, but the official size molded onto the side would be 205/55-16. A further factor is that the actual measurement of a tire is valid only if the tire is mounted on the specified measuring rim. Mount the tire on a narrower or a wider rim than the measuring rim, and the tire's dimensions will change. For instance, if you take a 225/45-17 tire that measures a true 225mm section width when on its measuring rim (usually 7.5") and squeeze that tire onto a stock 7" Mazda6 rim, after mounting, the actual section width will measure closer to 220mm.
The fender rolling is not for sticking out but for tucking in. :wavey: The front fenders come from the factory with the inside edge of the wheelwell neatly tucked in, but at the rear, on the inside of the fender, Mazda leaves the edge kind of raw. That raw edge can catch on the outside sidewall of the tire when the wheel goes over a bump. Fender rolling, invisible from the outside, just tucks in that raw edge. See the "Photographic Journey" here: http://mazda6tech.com/index.php?option=com...17&Itemid=1
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Aha! That's what you meant by granularity. It makes perfect sense! (Poof!! Light bulb goes on in head). Do tire manufacturers round down or up to the nearest "5" size? The rolling fenders tool - I'll see if body shops have that here. Thanks a ton, bud.

:laugh: You probably do not realize that you addressed that to the biggest anti--"all season" tire fanatic on this board. I completely agree with and applaud the Japanese regulations. (Short summary: the same technology that makes an "all season" tire stick to snow also makes water adhere to the tread instead of being repelled from it as it is on "summer" tires -- and that, in turn, makes wet traction of "all season" tires crappy.) There are others here who believe that the Tooth Fairy has exempted them from the compromise built into every "all season" tire, and who get upset when I disagree with them.
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:lol: Hey don't get me wrong. The JDM OEM Dunlops are awesome - I can take really tight turns at speed with them - something that all seasons might not be able to do. I would love to have separate sets for summer, winter and snow, but as I noted in my later edits, I don't have the friggin space to store winter tires nor the space to swap them here (I could pay to have a tire store do it and have them store the wheels but that to me is ridiculous). And winter tires that prove their worth maybe 2 times per winter ain't worth it - in the dry when there isn't any snow, well, it just sucks. All season tires are a compromise, out of necessity, for the winter. I'll still have my 17in rims if I want to go back to them.
 
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