16x7.5 koseis help

[var1ant]

I really want to get a set of 16x7.5in k1s for my car. I intend to road race it and figured this size would be the best for my needs. If anyone has anything to say about that feel free to tell my why i'm an idiot. I've been seeing people talk about tirerack selling them and such but I have yet to find where to order. Also would et20 be the correct offset?

[permit]

You have to email or call a sales rep directly. Just tell them you need a set drilled to 4x100. They come in et22 and et40.

[Mystikal]

You want the ET22 ones. And 225/45/16 rubber.

[rwh11385]

To roadrace, I'd buy some 15x7 ones.....

1) Common. Easier to buy a spare or resell them.
2) Cheaper.
3) Size is ITS-legal. Dunno about 16s
4) Less of a penatly for plus-sizing in at least Auto-X, and perhaps TT as well
5) Tires cost a lot less. 205-50-15s are perfect tire for a car our size IMO

Those are my reasons. And

6) Learning on a 205 would be putting you a lot slower, and when you mess up, not be as bad. And a 225-45-15 race tire would be sweet in the end.

[PeaveyBassist]

I thought your 205's were "too much tire" for you heeter ;)

Will

[rwh11385]

shut it. i got used to them after another session. I was just humbled by the newfound limits.

still wasn't using them to their full potential though. and probably won't for a while. but shit....195s were getting greasy half way through the session in May&June, but the 205s didn't do so.

of course, maybe some better 195s could handle the heat, but 205s are a great size for the weight of the e30

[Jarvis]

I really want to get a set of 16x7.5in k1s for my car.

I will have a practically brand new (used once on the track, I believe) extra set of those in about a month.
PM me for details if you're interested.

[Mystikal]

of course, maybe some better 195s could handle the heat, but 205s are a great size for the weight of the e30

I don't think that's a valid conclusion without the testing of wider tires in the same venue. Yes, 205 is wider than 195. Yes, it will seem more "right" for the E30. But without trying 215 or 225, it's an incomplete idea.

[rwh11385]

Jay, the smallest (cheapest size) tire that can handle the weight, put up with the braking, and acceleration of an e30, is the ideal one IMO. Therefore, I don't need to test bigger tires to believe 205s are ideal for me, and anyone looks for what I am looking for.

195s had an issue. They got greasy halfway through the session. Same tires, wider size: the problem is solved.

205-50-15s are cheap. They are common. They are cheap. And they do the job. Wider tires may do the job better, but for a cost.

Put into economics:
The mariginal cost for a wider tires increases, while the marginal benefit of a wider tire past 205s would decrease.

[Mystikal]

..."would" is your problem. Scientists don't come to conclusions based on what "would" happen, without any sort of trial.

Also:
205/50/15 R-S2 - $85
215/45/16 R-S2 - $91
225/45/16 R-S2 - $94

Your stated price difference is almost non-existent.

[rwh11385]

The slope of marginal benefit is negative. As the tires get larger, the additional benefit decreases compared to what you got when you first upgraded. Diminishing returns. 285s compared to 245s won't be as much better as 245s would be in comparison to 205s. Ask Alex, he had a hard time differentiating between his 17s and 18s with larger rubber when I met up after his testing session at Grissom.

The best tire for your buck is where the marginal cost of the tire is equal to the marginal benefit. Right now, I don't believe paying for the additional tire of a bigger one is worth the benefit from that more rubber. Who really knows where the "best" compromise is. For me, it's a 205-50-15.


Don't use RS-2s. Same introductory low prices that Falken used.

Bridgestone SO-3s:
Size: 205/50WR15
Price: $138.00
Size: 225/45YR16
Price: $190.00

Price difference is almost non-existent indeed.....

[Mystikal]

We all know there are diminishing returns, but 225s on a 2800+lb car is NOT by any means excessive. 205s are relatively (meaning compared to other car's setups, weight/contact patch) small, and you know it.

And why not run R-S2s? They're the second-stickiest tires in the dry around, only the pricey RT-615s are faster, and they cost nothing. I don't see the downside.

And you still have no primary experience with anything bigger than 205s, and nothing you post can change that fact.

[rwh11385]

And why not run R-S2s?

Because you're using them for cost comparison, which isn't within the realm of normal, as previously stated. Introductory low prices should not be used as an attempt to prove the prices aren't that much different. Referring to an established tire, it is quite clear there is a price differential.

Meh. I'll swap tires with Case and see how much difference there is in 225. But the damn point Jay is I am satsified with 205s and they are cheap. I'm not wanting to spend any more $ per tire to get more rubber really.

If var1ant wants to roadrace, he should stick to the same tire and push that same tire to the max. In the quest for more and more seat time, a cheaper tire = good. A cheaper wheel to replace = good. A lower limit tire = good. Therefore, I say 15x7 = good with a 205. A 225 while providing more grip, does not necessarily mean it gives him anymore benefit in his roadracing. He'll go faster, but he'll not necessarily learn anymore. There is no need for 16x7.5s to "roadrace"

Yes, 205s may be comparably small. You get to react their limit faster than with a wider wheel. And have more time to feel them out. And I believe it'd be easier and better to go with the small one. I had problems with the 195s, so a 205 is very benefitial. Charlie has been running 195s for years and although small, he has still learned a lot. And saved a lot of $ running puny sized cheaper tires. 195s would be a great choice, but don't work for me, and it may be the size of the car/rubber on tire. But 205s seem up to the job, especially being as hard on them as the SM guy made me.

[Mystikal]

Because you're using them for cost comparison, which isn't within the realm of normal, as previously stated. Introductory low prices should not be used as an attempt to prove the prices aren't that much different. Referring to an established tire, it is quite clear there is a price differential.

If the tire exists and is of excellent quality, why not use it as an example? Okay, maybe it's not a universal rule that the 225's don't cost much more than 205's, but they ARE available, and will be that way for a while to come. If not, just like how people said the RT-215 would be the last of the cheap good, a new entry will fill the void in the market. Like cheap drugs, there will always be a substitute. And this substitute happens to be one of the BEST tires on the market.

Meh. I'll swap tires with Case and see how much difference there is in 225. But the damn point Jay is I am satsified with 205s and they are cheap. I'm not wanting to spend any more $ per tire to get more rubber really.

Thank you. I wasn't disputing any of your points regarding it being a good beginner tire or the value of 15" setups, I was merely suggesting that you don't have the experience and/or credentials to make statements like these:

205-50-15s are perfect tire for a car our size IMO

205s are a great size for the weight of the e30

Put into economics:
The mariginal cost for a wider tires increases, while the marginal benefit of a wider tire past 205s would decrease.

...there is no proof of any of these, you're just making empty claims based on your own assumptions. If you had driven on the same tire in 215 or 225, you'd have some evidence to support your theory, but you haven't. Therefore they are bogus conclusions, and have become the "misinformation" on R3V you yourself have complained about.

[rwh11385]

why not use it as an example? Okay, maybe it's not a universal rule that the 225's don't cost much more than 205's

Why not use it as example? Because it's an exception to the general rule of pricing for 225s in 16" tire versus 205 in 15". You posted the prices as a means to say the prices aren't that much different, but those tires are the exception, so posting those prices isn't saying anything except for one singular cheap tire is cheap for a lot of sizes. This does nothing for the argument that 225s in 16" are more expensive than 205-50-15.


And I've stated that my OPINION is that 205s are the perfect size for e30s. If you don't fucking like it, buy bigger tires. You're not me. But what works for me could work for others. My experience is that 205 is enough tire to avoid overheating at the track and getting greasy with cheap Auto-X tires. Therefore, it is enough. And since they are smallest that did this for me, and cheapest, they are ideal in my eyes.

If I didn't want the smallest, cheapest tire that would satsify me, then yes, I should try out 225s, but I don't want that. I don't care to get the most possible tire and fastest handling. I want a tire I can learn from and it is easier to me to learn a small tire with lower limits than one is above my head so much more so (like how novices aren't supposed to learn on R compounds....I want the least tire that will work for me) And it is a principle of economics that the marginal benefit decreases, THERE IS NO NEEDED EVIDENCE TO SUPPORT THIS. Why did you quote that??!?

I want smallest possible that works for me, which is 205s. Therefore, 205s are ideal for me. And may be so for anyone in my shoes. Since var1ant is wanting to roadrace, they should work well for him as well. But YOU go ahead and recommend 225-45-16s and 16x7.5 Koseis....since you know so much about roadracing yourself.....