15x8 sub 15lbs for under $100!

[Jean]

Not every time is the same width...example my 225/50 rubbed in the back ...and I am on fairly stiff coilovers. So, depends on the tire width and how low your car is.

[MaxBell]

depends on the tire and early or late e30, 225 Nitto NT01s and Toyo RA1s both clear on my early body with no issues.

The car is an 1987 325i. I want to tuck a little tire, will 15" with 205/50/15 get me there?

I disagree. My 205s are perfectly square on my wheel so I'm getting the maximum contact patch.
I'm sure with a 225 I'd have more grip but I wouldn't exactly call running a 205 a waste

Square? So I'm not going to be worrying about any weird stretch fitment issues?

[Balleristic31]

I'd say there is maybe 5% stretch. But I wouldn't even consider it stretch.

[Brandon12V]

I'd say there is maybe 5% stretch. But I wouldn't even consider it stretch.

if you go by the bead, then technically you are not stretching. Going by the rim of the lip, you should be stretching roughly 5-8mm per side. can I see a close-up of your tire mounted on wheel?

[zxert]

205 is still a bit of a stretch on a 50 tire. Run 215s at least for any track use.

[Balleristic31]

This isn't the greatest pic, but its all I have on my phone. Its TR 15x8 compared to stock wheel/tire size.

[Brandon12V]

Yep that looks about right. You would and I'm guessing are, currently, fine under track conditions. The main reason you shouldn't run undersized tires is because when lateral force is put on a tire, it will flex slightly or heavily pending the strength of the sidewall. See that lip on the tire that laps the outer rim of the wheel? It's there for that reason along with adding rigidity to the sidewall. When the sidwalls begins to flex, air pressure keeps the bead pressed against that lip and, as the sidwall bends, the lip on the tire laps the outer rim of the wheel. That is why the outer width of you wheel is actually wider than what it is spec'd at (I.E. 15x8 is really more like a 15 x 8.25-8.5). In your case, nothing drastic would happen. If running a 195 or smaller tire at the extent of it's limits, you can understand my point better as the lip of the tire would never reach the outer rim of the wheel. Thus, the bead would pop. Running an oversized tire isnt exactly a good thing either. For reference I'm not speaking out my ass. I was a manager at Discount Tire for a year and we learned all about this stuff. Tires are actually very interesting to learn about once you understand what different tread patterns, sizes, etc. can do to its ability to perform.

[Wh33lhop]

Yep that looks about right. You would and I'm guessing are, currently, fine under track conditions. The main reason you shouldn't run undersized tires is because when lateral force is put on a tire, it will flex slightly or heavily pending the strength of the sidewall. See that lip on the tire that laps the outer rim of the wheel? It's there for that reason along with adding rigidity to the sidewall. When the sidwalls begins to flex, air pressure keeps the bead pressed against that lip and, as the sidwall bends, the lip on the tire laps the outer rim of the wheel. That is why the outer width of you wheel is actually wider than what it is spec'd at (I.E. 15x8 is really more like a 15 x 8.25-8.5). In your case, nothing drastic would happen. If running a 195 or smaller tire at the extent of it's limits, you can understand my point better as the lip of the tire would never reach the outer rim of the wheel. Thus, the bead would pop. Running an oversized tire isnt exactly a good thing either. For reference I'm not speaking out my ass. I was a manager at Discount Tire for a year and we learned all about this stuff. Tires are actually very interesting to learn about once you understand what different tread patterns, sizes, etc. can do to its ability to perform.

Plenty of people run stretched tires at the track and the sidewalls are stressed differently under stretch (compression/extension which is inherently stronger when compared to shear force). I am not a subscriber to stretching tires but it is not as simple as "the bead will pop if you stretch a tire." No offense, but it sounds like they taught you what you needed to learn--what to tell customers when they ask why to match tire width to wheel width.

Try running a 225/45 on a 15x7, a 15x8 and a 15x9 and tell me which gives you more grip, better transient response and less sidewall flex. Just sayin'. ;)

[Brandon12V]

I'm not saying the tire WILL pop under stretched conditions, even though I worded it that way. I am on my iphone so I'm thinking faster than I can type. Apologies for speaking in absolutes. :) More simply, you run a much higher risk of it happening. You can read up on this on the internet, lol. I just happened to learn first through my ex-employer 6 years ago. All tires' sidewalls will flex differently depending on the model and make. There is a forgiving ground between where you can use a tire on different sized wheels. Yes, a 225/45 will work on all those wheels and will transition between turns differently on each wheel. I've seen plenty of people track on undersized tires as well and be fine. I've also seen people run undersized tires a pop a bead. As far as less sidewall flex, true. running a 225/45 on a 15x9 is nearly the same as running a 205/45 on a 15x8. So, relatively speaking, it would look the same as the set shown in guy's pic above. My point was, more or less, to show the purpose of the bead on the tire and the misconception of 'dangerous' or 'bad' stretch.

[Balleristic31]

As far as less sidewall flex, true. running a 225/45 on a 15x9 is nearly the same as running a 205/45 on a 15x8. So, relatively speaking, it would look the same as the set shown in guy's pic above..

Just for clarification, I'm running a 205/50 in that pic. Not 45

[Brandon12V]

ahhh god damnit. well my point was made.

[Wh33lhop]

I'm not saying the tire WILL pop under stretched conditions, even though I worded it that way. I am on my iphone so I'm thinking faster than I can type. Apologies for speaking in absolutes. :) More simply, you run a much higher risk of it happening. You can read up on this on the internet, lol. I just happened to learn first through my ex-employer 6 years ago. All tires' sidewalls will flex differently depending on the model and make. There is a forgiving ground between where you can use a tire on different sized wheels. Yes, a 225/45 will work on all those wheels and will transition between turns differently on each wheel. I've seen plenty of people track on undersized tires as well and be fine. I've also seen people run undersized tires a pop a bead. As far as less sidewall flex, true. running a 225/45 on a 15x9 is nearly the same as running a 205/45 on a 15x8. So, relatively speaking, it would look the same as the set shown in guy's pic above. My point was, more or less, to show the purpose of the bead on the tire and the misconception of 'dangerous' or 'bad' stretch.

Fair enough--and you are correct. I didn't mean to jump down your throat. I should say that I have seen zero accidents due to stretched tires though.

[Brandon12V]

It's cool man, a forum is a collection of input. I was just trying clarify mine, not defend myself. :p

[MaxBell]

Ok great, so now that's over, I have a question regarding fitment.

15x8 vs. 16x8. The car is a daily driver and I want some slight tucking, should I just get these, or some slightly larger other rims. I can't think of what each will look like.