Tire Talk Megathread

[rhyary]

Originally Posted by bigjae1976

Thanks!

I use an AiM SoloDL which measures G-forces. You can use forward accel G's to measure braking forces. I am not sure how accurate the SoloDL is.

Someday, I want to upgrade to an AiM dash in my E46 and install pressure sensors on the brake lines. Morehead Speedworks makes a handy brake line with a bung for a pressure sensor.

I am curious to see what the options are for an E9X.

The E92 CAN is awesome.
It has all the variables you want with the exception of Oil Pressure.

I have not seen yet a better CAN variables out of the box better than the E92 M3 using PT6 CAN.

One can say that it you want to learn how to drive fast, all you need is Solo2DL, E92 M3 and cheap tires.

Just using the accelerometers tells you what the car is doing. But not what the driver is doing. For example, it would be hard to see the difference between 100% and 85% throttle. Or 1000psi vs 800psi brake forces

Ideally, I want to see both, the driver input and the car output.

Back to tires, if you want to see the differences between same tires 9am session and 4pm session I don't think the accelerometers are detailed enough.

[redpriest]

I've never been impressed with Hoosiers. They wear out so quick, and they're not as fast as a true Pirelli DH slick.

[Bartledoo]

Originally Posted by redpriest

I've never been impressed with Hoosiers. They wear out so quick, and they're not as fast as a true Pirelli DH slick.

+1

[bigjae1976]

Originally Posted by redpriest

I've never been impressed with Hoosiers. They wear out so quick, and they're not as fast as a true Pirelli DH slick.

Scrubs (at least most of the time) or new?

[tsk94]

Only advantage of the Hoosiers I can see is they are DOT legal. So depending on your class you can run them with less penalty. Or for some classes that require DOT tires, it's your fastest option.
Beyond that, the DH seems to make more sense. Price point is similar (much less when you're talking scrubs), as fast and seem to wear better?


On the topic of tires reviews.. I like Jonathan from Tyre Reviews, but I will admit I do think some of his results are biased. Likely could be that many times they take place at a particular manufacturers facility. I don't think he's skewing results, but I strongly suspect that brand has a strong 'home field advantage'.. The raw data is one thing, but it's subjective feedback is great I find. It's not just all about what tire is the fastest - how it is to drive is just as important in my opinion.

[Vybz]

As long as we all agree that R888R's are absolute garbage, I'm good with that. Can't speak on whether there is brand bias on Johnathan's reviews, but they are quite in depth and helpful when trying to make tire decisions (imo). Furthermore with my limited experience in track day tires (I've only tried 4 in the 200 or lower tw category) I'd say that my personal opinion of the ones I have tried, echo his.

[tsk94]

Regular R888's are even worse then the R888R's believe it or not... I believe they are discontinued now, but man they were horrible.

[redpriest]

Originally Posted by bigjae1976

Scrubs (at least most of the time) or new?

I've only ever ran them new (+mine used, never someone's castoffs). They wore out so quickly it was astonishing.

[DrFerry]

Originally Posted by rhyary

When running tire tests and calling one tire faster than another because the delta is .1 or .2 differences is ignoring too many variables that happen on one lap. Also, running a test for 4 laps does not capture the full $1600 experience of a tire life. My point is that there is no substitute for your own goals of what you want from a tire. Having said that, I look at a lot of tire reviews to learn what the evaluation criteria are? when I drive, what should I look for in addition to lap time?

Well said on the issue of 0.1 or 0.2 seconds per lap not being significant on a road circuit. Heck, fuel load or the driver sneezing could cause that much of a difference.. In the 4 lap test (or 5 laps in the case of Johnathan’s screwed up GY SC3R session) cited above, the average lap time delta is = 0.6s ((0+0.9+0.9+0.6)/4) between the PS Cup 2R and GY SC3R. So probably significant given the standard deviation = 0.32s. You’re right again that a 4 lap test doesn’t capture the full ownership experience during a tire’s service life. Especially when in comes to wear life where one tire might last 50% longer than another or put a different way might last 50% shorter than another. Then there’s wet performance, braking, steering and subjective feel that many owners may prioritize over ultimate lap times. I’m guessing that is what you meant by stating, “my point is that there is no substitute for your own goals of what you want from a tire”. I can think of one German car maker that has at least twenty (20+) subjective criteria they evaluate at the Nurburgring over and above lap times. Not to mention those criteria and lap times are always compared back to back against a ‘known’ reference tire benchmark that the evaluation drivers know very well (referred to as “the reference tire”). Having your own goals of what you want from a tire is the right way to go about tire selection and purchasing (if not investing these days), but in my experience only a few people have the budget, the time or the knowledge to make educated and informed decisions. For this reason, I think third party test data from individuals like Johnathan, Grassroots Motorsports, ADAC, or even consumer feedback published by the Tire Rack, all combine to provide a great service nowadays that was glaringly absent in years past. Even IF sometimes those test results might have a ‘home field’ advantage they are often much better than little or nothing. What’s still lacking is comparative wear life testing, but that’s another subject entirely. Glad to hear you’re looking at tire reviews to learn what the evaluation criteria are. In answer to your question: “when I drive, what should I look for in addition to lap time?” I’ll give you a few to think about..

Tire Performance Criteria
1: Steering response and delay
2: Transient Stability
3: Vehicle Balance (Understeer/Oversteer)
4: Longitudinal Grip
5: Lateral Grip
4: Grip Progressivity

Evaluate Steering Response and delay by perceiving how soon (time domain) and how quickly (rate of acceleration) the vehicle changes direction below, near the limit of grip, and at large steer angles during steering maneuvers.
Evaluate Transient Stability when trail-braking, or under rapid ‘lift throttle’ deceleration, when cornering at or near the grip limit. Is the car easily upset when trail-braking or with lift throttle?
Evaluate Vehicle Balance by gauging the amount of rear tire sliding as an indicator of vehicle balance. More rear tire sliding means more oversteer, and by gauging the amount of steering wheel angle necessary to corner, at or near the limit of tire adhesion. More steering wheel angle in order to corner at or beyond the limit means more understeer balance.
Evaluate Longitudinal Grip by perceiving the efficiency of hard acceleration at corner exits or efficiency of hard braking.
Evaluate Lateral Grip by the speed of travel through a turn or perceiving the level of lateral acceleration (g-level).
Evaluate Grip Progressivity by perceiving how quickly and/or how slowly the vehicle slides when tire adhesion is lost. A gentle, slow slide that scrubs off speed with a gentle regain of adhesion is regarded as good progressivity.

Now those criteria listed are more than a few, but consider the test driver’s skill working for a car maker - with over twenty such tire evaluation criteria - being tested while blasting around the Nurburgring at huge rates of speed. In short, they have to leave some speed on the table in order to keep a part of their brain engaged in evaluation and not wreck during the test. So that “N” on the sidewalls of "P" car OEM fitments really does take a lot to earn..

[rhyary]

Most of the tire reviews I watch evaluate the front tires. While the rear tires are mentioned, the rears are not a major factor.

I am sure that when a manufacture evaluate tires they give all 4 tires equal consideration.

Objectives:
To win a race, one tenth of a second count.
To win HPDE, value has more weight.
If I want to "win" a second day at NYST, meaning finishing up 7x20min, I cannot only think about two tenth of a seconds.

My right front will be delaminated if I am on 100% throttle on the long left T-6. So I need to rotate the car in a specific place by driving more like a V and getting off the throttle and on again.

It may not be the fastest way. With Hoosiers I can be on the throttle without understeering, but there goes $500/tire.

This is what I mean goals. Typically my goal is to maximize my driving time and drive my best, and secondary do my best lap time. But a time attack driver goal would be to go fastest for one lap.

If i drove 7x20 min i met my goal
If Time Attack got a PB by one tenth, he met his/her goal.

The choice of tires, and how to use them is directly be affected by the usage.

[omgzirra_exe]

Originally Posted by Vybz

As long as we all agree that R888R's are absolute garbage, I'm good with that. Can't speak on whether there is brand bias on Johnathan's reviews, but they are quite in depth and helpful when trying to make tire decisions (imo). Furthermore with my limited experience in track day tires (I've only tried 4 in the 200 or lower tw category) I'd say that my personal opinion of the ones I have tried, echo his.

the best part about car meets is having some one tell you they have R888R's and that they are good. and i call tell them with a straight face they suck and walk away.

[derbo]

Originally Posted by omgzirra_exe

the best part about car meets is having some one tell you they have R888R's and that they are good. and i call tell them with a straight face they suck and walk away.

#CloutIGTires

[bigjae1976]

Originally Posted by redpriest

I've only ever ran them new (+mine used, never someone's castoffs). They wore out so quickly it was astonishing.

So how long do the DH slicks last when new?

[dparm]

Originally Posted by tsk94

On the topic of tires reviews.. I like Jonathan from Tyre Reviews, but I will admit I do think some of his results are biased. Likely could be that many times they take place at a particular manufacturers facility. I don't think he's skewing results, but I strongly suspect that brand has a strong 'home field advantage'.. The raw data is one thing, but it's subjective feedback is great I find. It's not just all about what tire is the fastest - how it is to drive is just as important in my opinion.

He's just one tester with one approach. I would not be making decisions solely on what he posts, for the reasons you say. I do like his channel because it gives me a preview of tires that will be available in the US soon. Plus, his educational videos are useful (e.g., snow tires versus all seasons). I also don't use Tire Rack for my sole purchasing choices, though to their credit they have only one test facility with a fleet of identical cars.

I try to look at a lot of reviews/tests and see what patterns emerge. For example, the Michelin PS4S is near the top of many test types, across range of methodologies, and a variety of cars. To me, that signifies it is probably a great tire.

For a street tire, I am usually prioritizing wet performance and road noise...no one likes the sudden realization that a car is sketchy in bad weather, nor do they like the drone of tires on long trips. If it has good dry performance and is durable, it's just gravy.

[Kelse92]

Originally Posted by tsk94

On the topic of tires reviews.. I like Jonathan from Tyre Reviews, but I will admit I do think some of his results are biased. Likely could be that many times they take place at a particular manufacturers facility. I don't think he's skewing results, but I strongly suspect that brand has a strong 'home field advantage'.. The raw data is one thing, but it's subjective feedback is great I find. It's not just all about what tire is the fastest - how it is to drive is just as important in my opinion.

This is most definitely the case I think. Marketing
Always good to look at multiple angles and tests though to parse through and come up with your own conclusions.
At the end of the day, testing yourself is the best thing, but it’s not really cost effective

[rg1220]

So... I feel dumb asking, but I'm really just trying to determine what to do. Last track event was really cold (~40F). First session I started at 30psi and it got up to 39psi. I kept bleeding them down throughout the day to try and keep them at around 34psi. Evidently, I should have been targeting closer to 36psi with some slower warm up laps. Also, I have -2.7° camber.

My front right Michelin PSS has plenty of tread except on the outside shoulder. Does this need replaced? I'm thinking yes.


According to Tire Rack (https://www.tirerack.com/tires/tiret...jsp?techid=161)
> Once the lateral grooves in the shoulder start to disappear, the end is near - it's time to replace your tires.

Next track weekend is at Summit Point Shenandoah. I think I'm going to increase camber to -3.0° and toe-out to 0.2° (from -2.7° and 0.1°). And go with PS4S upfront (rear PSS are still in great condition).

Lessons learned
1. Pressure is important for more than just for grip.
2. Rotate tires in middle of track weekend.

[Kelse92]

Keep an eye on that one but it's probably worth replacing.
Definitely a good idea always to rotate tires, and why a lot of people run square setups, especially if you're consistently driving a track in the same direction. You're always going to wear the outside front tire out first if you don't rotate.

[fanatic1]

Originally Posted by redpriest

I've only ever ran them new (+mine used, never someone's castoffs). They wore out so quickly it was astonishing.

Agree, astonishing is 5 sessions and corded left front at Buttonwillow. Hindsight, would've rotated quicker.

Was running scrubs, but put the one that looked virtually brand new on the left front.

Recalibrating to the grip DH offers was challenging, there was a lot left according to the data.

[woodchuck072]

Info on Nexen's new 200tw tire:

[Kelse92]

Tire Rack should have a test review out on the new Nexen and Bridgestone Vs. the Falken and Yokohama in the next week or two. I'm interested and looking forward to reading the results.
It seems to me the Nexen will probably not be the fastest but slot in more towards the durability side and being just off the pace of the Falken but we'll see...

[spxxx]

Originally Posted by rg1220

So... I feel dumb asking, but I'm really just trying to determine what to do. Last track event was really cold (~40F). First session I started at 30psi and it got up to 39psi. I kept bleeding them down throughout the day to try and keep them at around 34psi. Evidently, I should have been targeting closer to 36psi with some slower warm up laps. Also, I have -2.7° camber.

My front right Michelin PSS has plenty of tread except on the outside shoulder. Does this need replaced? I'm thinking yes.


According to Tire Rack (https://www.tirerack.com/tires/tiret...jsp?techid=161)
> Once the lateral grooves in the shoulder start to disappear, the end is near - it's time to replace your tires.

Next track weekend is at Summit Point Shenandoah. I think I'm going to increase camber to -3.0° and toe-out to 0.2° (from -2.7° and 0.1°). And go with PS4S upfront (rear PSS are still in great condition).

Lessons learned
1. Pressure is important for more than just for grip.
2. Rotate tires in middle of track weekend.

If you're in a dry climate you could run them backwards since you'll wear the opposite side of the tire.

I've run plenty of directional tires backwards on track without issue (in the DRY obviously).

[tsk94]

Originally Posted by spxxx

If you're in a dry climate you could run them backwards since you'll wear the opposite side of the tire.

I've run plenty of directional tires backwards on track without issue (in the DRY obviously).

I've done the same as well to prolong tire life. Worth paying for the remount to potentially extend tire life 25-30%.