Comparing car lap times: Equal tires?

[Turbowned]

As an AE86 successor, this car carries an expectation to be able to drift, and with 200hp and super-sticky tires, would have left a lot of people disappointed. Also, those tires were chosen to give beginner drivers more feedback than your high-grip performance tire which gives less warning when it's at the limits of adhesion.

To say that the car's outright performance is held back by it's tires is an understatement. If the S2000, MX-5, or any other car were built with similar principles in mind, it would likely have mediocre touring tires as OE, too. Put the FR-S on RE050A's and stack it up against the S2000 and MX-5 (with the same driver, same track conditions) to get a sense of it's true performance against its competitors.

[fatoni]

Originally Posted by Turbowned

As an AE86 successor, this car carries an expectation to be able to drift, and with 200hp and super-sticky tires, would have left a lot of people disappointed. Also, those tires were chosen to give beginner drivers more feedback than your high-grip performance tire which gives less warning when it's at the limits of adhesion.

To say that the car's outright performance is held back by it's tires is an understatement. If the S2000, MX-5, or any other car were built with similar principles in mind, it would likely have mediocre touring tires as OE, too. Put the FR-S on RE050A's and stack it up against the S2000 and MX-5 (with the same driver, same track conditions) to get a sense of it's true performance against its competitors.

there are grippy tires that are equally if not more informative at the limit than the primacy. i do agree that it is a tire designed to let you enjoy the limits at a much more reasonable speed though.
the miata is the successor to the miata. mazda made a deliberate decision to not give it any more grip than it had in the 80s. also the miata was built to appeal to a wide audience and because of it, they suck in stock form. to get a sense of the miatas "true" performance youre probably going to need at least a set of rx8 sways.

[rice_classic]

Originally Posted by WolfpackS2k

2004+ S2000s (essentially the AP2) came from the factory on Bridgestone RE050s. And yes that tire is still produced.

yeah yeah yeah... but as soon as you saw the tire S03 mentioned you knew... you knew.

One in every group I guess.

[brewksy]

Originally Posted by fatoni

1: this isnt about what is common. it is about what is accurate. looking at things like the c&d lightning laps with the mustang on that limiter for over 9 seconds sounds like it is a pretty big deal.
2: sticky tires generate more force than less sticky tires. what situations are you talking about where less stress is going to show platform deficiencies? the closest thing to a test like this ive seen has been done by the folks over at 949racing and fecompetition. in that test they say this: " In this configuration, the car has way more grip than it does suspension control. Its fast, but sways through corners in a manner that isn’t confidence inspiring when trying to go fast." about using sticky tires on an otherwise stock frs. if companies really thought like that, i would wager that we would see much wider tires coming off the lots.

1: Yes, it is about what is common. And it certainly is about accuracy. But you found *one* example in the C&D Lightning Lap where the ECU speed limiter impacted a car's performance. You know how many lap results were affected by the tires on the car? Every singe one of them - I can even point to every single review where they've tested different tires on the same car (I shouldn't even have to find sources for this) and had drastically different lap times around a track. That's a big deal. Is the ECU speed limiter a big deal? Not even close to being relevant for 99% of the car tests that happen in magazines.

2: I don't even know what we're arguing about here. Tires make a profound difference in performance of a car, are chosen because of a specific price-point the automaker is trying to hit and at the same time maximize traction and control that wouldn't otherwise be possible with the chassis, and are easily the fastest wear-items on any car (besides oils and filters, I suppose).

DarkSunrise said it best - if you're the general public that doesn't care about lap times, then keep everything stock. If you're an autoXer, you would appreciate the comparison of cars on similar rubber. I'm fine if you're in the former group, but it doesn't mean those of that would like better comparisons are wrong in any way.

[midenginebias]

Originally Posted by fatoni

like what kind of deficiencies?

Cut a couple of tenths 0-60.

A few more tenths 1/4 mile.

Braking distance.

Skidpad rating.

If anything, I was surprised how well the Fr-S did with the summer Prius tires.

[fatoni]

Originally Posted by brewksy

1: Yes, it is about what is common. And it certainly is about accuracy. But you found *one* example in the C&D Lightning Lap where the ECU speed limiter impacted a car's performance. You know how many lap results were affected by the tires on the car? Every singe one of them - I can even point to every single review where they've tested different tires on the same car (I shouldn't even have to find sources for this) and had drastically different lap times around a track. That's a big deal. Is the ECU speed limiter a big deal? Not even close to being relevant for 99% of the car tests that happen in magazines.

2: I don't even know what we're arguing about here. Tires make a profound difference in performance of a car, are chosen because of a specific price-point the automaker is trying to hit and at the same time maximize traction and control that wouldn't otherwise be possible with the chassis, and are easily the fastest wear-items on any car (besides oils and filters, I suppose).

DarkSunrise said it best - if you're the general public that doesn't care about lap times, then keep everything stock. If you're an autoXer, you would appreciate the comparison of cars on similar rubber. I'm fine if you're in the former group, but it doesn't mean those of that would like better comparisons are wrong in any way.

just changing tires and nothing else isnt any more fair or informative than keeping things stock. my providing one example of an ecu isnt any less valid than the one example of swapping tires on your one frs. take a look at miatas. on equal tires the na8 is faster on equal tires but when you look at the rules, the na6 is the faster car in the classes. changing tires doesnt make any more sense than changing other things too. thats all ive ever been saying.

Originally Posted by midenginebias

Cut a couple of tenths 0-60.

A few more tenths 1/4 mile.

Braking distance.

Skidpad rating.

If anything, I was surprised how well the Fr-S did with the summer Prius tires.

its impossible to equate those things to a chassis alone. if you change the tires on any chassis those numbers will change. quarter mile times, braking distance and skidpads have next to nothing to do with the chassis. if by implying that improving those statistics via tires is hiding chassis issues, then every single car ever has chassis deficiencies.

[Kunzite]

fatoni, you're not only claiming that using the same tires isn't "fair", which is debatable; but you're also claiming it's not informative.
(e.g.) Skidpad figures close to an Elise are very informative. But you know what isn't? Changing many things at once, because you don't know what's doing what.
I can't agree that purposely changing one specific thing, that's not a constant during the lifetime of the stock car, is the same as changing many other things at once.

[WolfpackS2k]

Originally Posted by rice_classic

yeah yeah yeah... but as soon as you saw the tire S03 mentioned you knew... you knew.

One in every group I guess.

[fatoni]

Originally Posted by Kunzite

fatoni, you're not only claiming that using the same tires isn't "fair", which is debatable; but you're also claiming it's not informative.
(e.g.) Skidpad figures close to an Elise are very informative. But you know what isn't? Changing many things at once, because you don't know what's doing what.
I can't agree that purposely changing one specific thing, that's not a constant during the lifetime of the stock car, is the same as changing many other things at once.

thats not at all what im saying. what i am saying is that it isnt any more fair or informative than keeping the factory tires or changing some other thing.

skidpad tests are not only next to worthless as far as handling goes but they should only be compared on the same surface with the same radius. close to the elise skidpad numbers? was that the .95g or the 1.03g. the zr1 posts higher numbers than the elise ever did. is the corvette a better handling car than the elise?

you dont have to agree with anything im saying but being able to identify what is making a difference has nothing to do with saying changing tires and only tires alone can be changed in comparisons

[midenginebias]

its impossible to equate those things to a chassis alone. if you change the tires on any chassis those numbers will change. quarter mile times, braking distance and skidpads have next to nothing to do with the chassis. if by implying that improving those statistics via tires is hiding chassis issues, then every single car ever has chassis deficiencies.

While you're right about equating that to a chassis alone, getting high quality tires still hides deficiencies.

Tires have little to do with the chassis, pending setup, suspension geometry, etc.

It's not that every car has a chassis deficiency. That's too extreme a point. The modern chassis of cars nowadays are tremendously better than cars of yesterdecade.

The point is, great tires inflate great results on track tests. Those numbers are what most car buyers actually look at.

The more informed enthusiast will want to see lap times of different chassis with the same tires. Why? They're more likely to use the car for that given application.

My point is this. All sports cars for sale in 2012 have a great set of grippy tires except one car. The FR-S. So, when that "average tire" still puts up huge numbers for typical testing, it says a lot about the chassis, since the tires aren't inflating results. Rather, using narrow 215 tires that belong to a Prius show how much potential the chassis actually has.

[fatoni]

Originally Posted by midenginebias

While you're right about equating that to a chassis alone, getting high quality tires still hides deficiencies.

Tires have little to do with the chassis, pending setup, suspension geometry, etc.

It's not that every car has a chassis deficiency. That's too extreme a point. The modern chassis of cars nowadays are tremendously better than cars of yesterdecade.

The point is, great tires inflate great results on track tests. Those numbers are what most car buyers actually look at.

The more informed enthusiast will want to see lap times of different chassis with the same tires. Why? They're more likely to use the car for that given application.

My point is this. All sports cars for sale in 2012 have a great set of grippy tires except one car. The FR-S. So, when that "average tire" still puts up huge numbers for typical testing, it says a lot about the chassis, since the tires aren't inflating results. Rather, using narrow 215 tires that belong to a Prius show how much potential the chassis actually has.

great tires will inflate results on both great and shitty chassis. if it does the same things to both ends of the spectrum, how is that hiding anything?

[Kunzite]

@fatoni:
Taking your words exactly, "it isnt any more informative than keeping the factory tires" - that's not true. It is very informative, if that's the piece of information you're looking for. Guess what: that's the piece of information we're looking for.

Skidpad is one test, no it can't actually measure "handling" but is there even a metric for handling? It's a good example, though, since it's so tire dependent; no car can compensate for low-ish grip tires in this test. You're saying the same radius and same surface must be used; yet you want to test cars with different grip levels (tires). Strange.
What are the Edmunds numbers for the ZR1? 1.02g was all I found.

Being able to identify what is making a difference has everything to do with changing one single item (at a time).
Are you saying magazines should make e.g. suspension changes?

About your response to midenginebias: you just told us why it is so important to test all cars with "great tires" (i.e. to avoid comparing "inflated" results with "non-inflated" ones).

[fatoni]

Originally Posted by Kunzite

@fatoni:
Taking your words exactly, "it isnt any more informative than keeping the factory tires" - that's not true. It is very informative, if that's the piece of information you're looking for. Guess what: that's the piece of information we're looking for.

Skidpad is one test, no it can't actually measure "handling" but is there even a metric for handling? It's a good example, though, since it's so tire dependent; no car can compensate for low-ish grip tires in this test. You're saying the same radius and same surface must be used; yet you want to test cars with different grip levels (tires). Strange.
What are the Edmunds numbers for the ZR1? 1.02g was all I found.

Being able to identify what is making a difference has everything to do with changing one single item (at a time).
Are you saying magazines should make e.g. suspension changes?

About your response to midenginebias: you just told us why it is so important to test all cars with "great tires" (i.e. to avoid comparing "inflated" results with "non-inflated" ones).

i stand by that original statement. you seem to be overlooking how important that "if" you just added is. IF i was looking to see how the car performs with an extra 100 hp, a turbo seems to make sense in a comparison IF that is what im looking for. do you see how arbitrary that is? using data from different skidpads is like taking lap times from different tracks, not like changing tires.

if you google "skidpad test zr1" literally the first number you see is 1.06.

im not saying magazines should make suspension changes, im just saying that its just as fair as canging tires or anything else.

you keep missing my point and i dont really feel like running around in circles with you

[WolfpackS2k]

Road & Track tested the ZR1 in 2010 and recorded 1.04g

They tested it again in this month's issue and recorded 1.08g.

Not sure why you're looking for Edmunds numbers?