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Without instrumented data to analyze, your claims are circumstantial, inferential or anecdotal. It's not that I don't trust you, it's that I don't trust anybody who makes claims without cited sources to back them up. I'm not saying you're right or wrong, I just can't judge the situation for myself without understanding it better (which requires data).
You and OP (at least starting at post #25) applying data from top-tier competitive driving scenarios to daily driven street cars that might see track time once in a while.
Also, there was a largely semantic and syntactic debate on just what the definition of "stretch" is.
Again, not saying that I think you're wrong but there's a lot of nuance to the situation so blanket statements and broad generalizations are contraindicated. Sure, optimizing tire to wheel width is important, but...
1) it's part of a larger system
2) there are often mechanical and rules constraints
3) I'd bet that the overwhelming majority of people on this board have standard deviations on their lap times that are orders of magnitude larger than a 0.5" wheel width difference would make.
Stretch = a wider wheel width than tread width, this means the tire beads are outside the tread. hence its in a stretched position.
having a lot of seat time is great, when you want to push the next envelope then you look at what can be improved.
So let's look at facts.
The fastest time attack cars run on 11" wheels now, they used to run on 9.5" etc, why did these teams all choose 11" now?
Formula 1 is restricted to 13" wide wheels, why do they stretch their tires onto those wheels?
Almost all the Porsche racers, spec Miatas, etc, etc, etc all run wide wheels with slightly stretched tires.
I can't find the Michelin engineering presentation on their test results with Porsche saying to stretch the tire onto the wheel.
If you don't want to believe me, that is fine, but you are wrong. Just look at race cars and see what the trends are and how they set up their wheels. Mazdaspeed on miatas had written an article about going with wider wheels on the same width tire and having it be faster and better feeling.
also, having a muffin top tire shape results in unwanted snap oversteer and other negative downsides. New tire technology has masked some of the benefits or lessened them to a degree, but if you want the best tire temps, breakaway characteristics, tire wear, and lowest lap times, wide wheels and slightly stretched tires.
Again, you're posting inferences, circumstance, anecdote, and, now, marketing materials. I've read your arguments so repeating yourself isn't going to convince me but keep doing it if it makes you feel better.
FML. A 265/35-18 Pilot Super Sport is specified for a 10.5" rim. So it's not a stretch, the tire is designed for a 10.5" rim. That appears to be a ADVAN NEOVA AD08 R, so in a 265/35-18. It is also specified for a 10.5" rim.
FML. A 265/35-18 Pilot Super Sport is specified for a 10.5" rim. So it's not a stretch, the tire is designed for a 10.5" rim. That appears to be a ADVAN NEOVA AD08 R, so in a 265/35-18. It is also specified for a 10.5" rim.
If the definition of a stretch is having the tire beads outside of the tread width, it is by definition a stretch.
Therefore you want to stretch the tire onto the wheel, this is irrespective of wheel recommendations by tirerack or tire manufacturers.
In this scenario, It would only be a stretch if you were putting a 285/35-18 on an 18" x 11" wheel or larger. I mean the definition of the word "stretch" is to make make something longer or wider and in this case the tire is designed to fit on a 10.5" rim so there is no stretching of the tire.
"Stretch" has negative connotations with performance drivers. ....so I think that is the majority of the issue with this discussion. 9K's picture is what the stretched tire crowd runs....and that is stupid.
Like I said...I run 275 or 285-645 -18 slicks on 10.5" wheels and wouldn't call that stretched by any normal definition
Again, Monkey see, monkey do. And again, if the tire is specified for the width of the wheel that it is installed on, then it's not stretched.
This is stretched.
I don't buy the monkey argument. EVERYTHING is quantified among racers. If it isn't demonstrably faster, they don't do it (except maybe among the newbiest of amateurs).
And, yeah, that extreme stretch trend is ridiculously stupid.
Anyway, I think we are getting too hung up on the word, "stretched". The bottom line is, running a wide rim for a given section width yields a larger contact patch, which means more grip. It also results in a stiffer sidewall, which means improved feedback, therefore more control. All within reason, of course.
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Last edited by Steve Dallas; 12-08-2016 at 09:08 PM.
At some point the sidewall angle will cause abnormal heating and stress in the tire. I have seen more aggressively stretched tires delaminate the sidewalls because of the internal heat buildup.
There is NO Doubt that the wide rim will give better tire contact patch control......I've never said anything to the contrary. But to say a stretched tire will always give you better grip that a more traditional setup is not true
Back to the suspension subject, got the Ohlin's on.
Will post some pics later, it is dark over here.
The response is superb. Take corners at speed and it holds on like a train on track.
City driving is smooth. Having had all kinds of classic performance cars I was ready to sacrifice comfort for performance, but with this setup, no sacrifice whatsoever. It is as smooth as stock suspension. Unbelievable until tried.
Very greatly impressed.
What made me go for the Ohlin's versus the Bilstein was the comments I found about Bilstein, although excellent stuff as well, consensus was Bilstgein was a little harsh on street. So opted for the Ohlin's
Glad you like your Ohlins. I have them as well (before it was cool!). I find them to be very nice on the street and pretty decent on the track. With the right rebound settings on the street, the higher spring rates can be as comfortable as the OEM suspension. When pushed hard on the track, the front to rear spring ratio (don't want to get too technical) reveals itself as borderline crazy. I have no idea why they chose the rates they did, but the rear needs more spring, IMHO.
Just want to say it was raining cats and dogs today on my way to work.
It was scary. On dry roads the previous days notice a bit of tracking. Not bad.
I thought about toe in or out upon lowering. Perhaps a special alignment in order or something I do not know.
But driving in the rain on the freeway was sketchy. Car would catch every single line or imperfection on the road, as well as upon changing lanes, car would track wildly.
no real trick to driving this car in the rain other than the usual stuff
Make sure you have good tires. If they're all season, great. If not, make sure you have decent tread on them.
Slow down, it's easy to break the rear tires loose even with our torquless wonder for a car and that gets even easier in the rain.
You pretty much always need an alignment after replacing your suspension. Also, if you lowered the car very much, you need adjustable end links, which allow you to set proper preload on your sway bars, when the car is at rest. You don't want them binding at rest, and lowering the car more than about 3/4" will do that.
I have found the Ohlins coilovers to be interesting in two areas. The low frequency compression curve translates to making the car feel more busy, as it catches grooves and transmits them through the steering rack. You need fast hands to keep up. That can be a desirable characteristic on the track, where you are always at full attention, but it is not so desirable on the street, IMHO.
The strange choice of spring rates makes the front axle act like a fulcrum, which allows the rear to bounce and move more than normal, resulting in a surprising amount of oversteer when it is not expected. The RX-8 was designed with a 1.4 front to rear spring rate ratio. The Ohlins setup uses 2.0. That should result in terminal understeer, but it has done the opposite for me, and has had me scratching my head for months. Definitely leave your traction control on. Trust me.
You can minimize both of those effects on the street by setting the rebound lower than what is recommended in the manual. A setting of 5 or 6 from full soft should be about all you need. Experiment with the front to rear balance a bit in that range, once you get it aligned.
If I had seen this thread before you placed your order for Ohlins, I would have advised to you buy Bilstein PSS for $1080 shipped. They are very good coilovers for street and light track use and drop right into an otherwise stock 8 with no surprises.
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Last edited by Steve Dallas; 12-22-2016 at 09:54 PM.
I hear you. After taking cvare of the alignment I will work on the rebound settings following your advise.
I think the rear of my car is what tracks and acts weird now. I suspect toe is out of bounds. On dry pavement is tracks but it is fine. Nothing extraordinary.
But today on wet roads, it did go crazy, and I think toe being bad and out of bounds, the wet soaked roads allow each tire to wander and in fact they do, giving that twitchy feeling.
I expect the alignment to get rid of the weirdness, and then proper tuning of rebound will set it up.
Did not lower the RX too much. But just a modest lowering causes the rear to change standing position, toe and camber, and add IRS suspension and that is a recipe for wandering
After work went to the alignment place my buddies at RR&R advised me about
Great place. Not expensive and also clean and courteous. You know the feeling when the mechanics are grease monkeys grabbing your wheel, seating in your car.....that sucks! Not the case here.
The alignment was in order The rear had a lot of toe in. My suspecions were correct. All the time the tires on back kept driving in. On dry roads all that happened was tire wear. On wet roads it was skidding from side to side with help from rain water. . Each tire fighting the other one.
None of that now.
Just drove car like this for 5 days but only when driving in the rain it got conpelling. That made it urgent.
No more wild tracking. Before it would track even upon lane changes. As soon as a tire got in contact with the painted dividing lanes that tire would push car inside. Then it would release. Felt like an amusement park kart lol
I wouldn't put anything made by Megan on my car. And it doesn't make sense, my car is lower than anyone who tracks seriously and my car is still within stock alignment specs.
12-08-2016, 09:57 AM
