GT500 Track Performance

[Hack]

The cost of ONE SET of wheels isn't that cost prohibitive [edit for clarity, by that I mean the initial cost of the CF track pack]. I submit that anyone that can afford multiple sets, or to throw away CF wheels when they get damaged, are not driving GT500s at DEs.
If GT500s haven't stolen all the driving enthusiast press, it will be interesting to see if anyone compares back to back same day the 2019 GT350 with Cup2s with the GT350 R with the cup2s and CF wheels.

I guess we will probably see a GT500 comparison, with and without the CF package, those results will be interesting too.

I guess I have to repeat it again. I've NEVER had to replace a wheel. EVER. And I've been driving for more than 35 years. I put 33,000 miles on my GT350 and didn't replace a wheel.

Not sure why you are even bringing up replacing wheels. It just isn't a thing that normally has to be done on a street car with some occasional track use.

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[JR369]

I was trying to avoid the wrath of the GT350 R religion, but to me the difference was negligible. On track, NJMP Lightning. Maybe there's some magic track somewhere that has a much bigger difference.

Everyone has their opinions and I'm no professional racer for sure but I think your senses are dull. Driving a regular 16 350 at TA, I could tell right away how my R felt lighter and had more precise steering. Factor in the wind at 110-115 on the straights and the R aero difference is quite noticeable too. The R hugs the ground which heightens the precise steering capability even more. The difference was apparent between the two. The R is a congruence, in other words a harmony, of items that work together to make it what it is when you hitting its operating range. You ain't gonna feel a whole lot of difference on the street just putting around.

 

[JT1]

Everyone has their opinions and I'm no professional racer for sure but I think your senses are dull. Driving a regular 16 350 at TA, I could tell right away how my R felt lighter and had more precise steering. Factor in the wind at 110-115 on the straights and the R aero difference is quite noticeable too. The R hugs the ground which heightens the precise steering capability even more. The difference was apparent between the two. The R is a congruence, in other words a harmony, of items that work together to make it what it is when you hitting its operating range. You ain't gonna feel a whole lot of difference on the street just putting around.

Lol, I assure you my senses are not dull. I'm just not that susceptible to the placebo effect. Did you drive the cars back to back, same track same day?

[edit] Stop trying to get me in trouble with the R mafia! lol

 

[JT1]

I guess I have to repeat it again. I've NEVER had to replace a wheel. EVER. And I've been driving for more than 35 years. I put 33,000 miles on my GT350 and didn't replace a wheel.

Not sure why you are even bringing up replacing wheels. It just isn't a thing that normally has to be done on a street car with some occasional track use.

All I can say is MN must do a much better job of fixing roads than PA, lol. Glad you have had good luck. Your assessment of "occasional" track use must in fact be very occasional, if not rare.

Cup 2s last what, 4K-8K miles? And what 6-8 track sessions? There's a reason most guys at the track have 4 or 8 tires on rims on their trailer, in addition to the 4 on the car.

As for me, there's very few people I'd trust to mount and demount tires on my 4K each rims. If I had CF rims, I most likely would rarely use them on track.

 

[Strokerswild]

LOL, Minnesota DOT and the notion of doing a much better job of fixing roads is an oxymoron in most areas.....

 

[Hack]

LOL, Minnesota DOT and the notion of doing a much better job of fixing roads is an oxymoron in most areas.....

Usually when there's a 3 foot by 2 foot by 1 foot deep pot hole, you remember where it is and are able to dodge it. This year was worse than some, with several places in my commute having potholes covering so much of the road that it was nearly impossible to even dodge all of them.

All I can say is MN must do a much better job of fixing roads than PA, lol. Glad you have had good luck. Your assessment of "occasional" track use must in fact be very occasional, if not rare.

Cup 2s last what, 4K-8K miles? And what 6-8 track sessions? There's a reason most guys at the track have 4 or 8 tires on rims on their trailer, in addition to the 4 on the car.

As for me, there's very few people I'd trust to mount and demount tires on my 4K each rims. If I had CF rims, I most likely would rarely use them on track.

I didn't buy an R because I didn't want to change tires that often. However, I did have to change the fronts a couple times and the rears 3 times in the almost 4 years I owned the car.

I get that anyone would be concerned about damage to an expensive rim, but I would trust my local tire guy to do it, no problem. I didn't ever get any damage to my aluminum rims.

And I've had many, many sets of tires installed in my life and never had a rim damaged. So it seems odd to worry so much about it.

The tracks I've gone to absolutely don't have pot holes. And I've never damaged a wheel on track either. Are you saying that your local track has pot holes?

 

[ScottX]

Carbon fiber anything including wheels is comprised of a carbon fiber matrix type woven weave encapsulated by a thermoset or thermoplastic resin. The difference is thermoplastic will soften and deform with heat.thermosets(for you old schoolers think Bakelite, like old time oven knobs) will not soften or deform with heat, but it will burn. These are hydrocarbon oil derivatives. PLASTIC IS NEVER STRONGER THAN THE DAY IT WAS MADE.All plastics strength degrade over Time and with stress. Ever hear of coldflow or creep?just look at a plastic hanger hook deform with a heavy garment.Never seen that, that’s creep. Plus environmental factors definitely add to degradation, uv(which gets stronger every year)smog,hello L A,and pretty much everywhere in the USA,and extreme thermo cycling( think red hot brakes). Hasn’t anyone seen all the gt350R wheel failures from pothole impact? So don’t fret too much over cf wheels. Way better off with forged wheels. Retired plastics engineer 30 + years with the biggest petrochemical companies in the world.They make the plastics you all use. And remember while plastics are great(no modern world without them) they have limits. And yeah I’ll kick this hornets nest.just my professional 2 cents.

 

[Hack]

I think some of you guys should go back to steelies. Every material has pluses and minuses to it. Steel is definitely stronger than aluminum and you can design steel to have an infinite fatigue life.

 

[JN66]

Any of you fellas know when we should be hearing some additional info on lap times at the Ring, weight, 0-60, etc?

Rumours? Haha.

 

[BillyJRacing]

Read the post. Nobody said anything about a 10/10ths benefit at any speed. It was worded that "the cost to benefit for someone not running them 10/10ths is rather high." Of course the improvement they can provide runs across the spectrum. Point was, the are an extremely expensive item for those that never exploit the delta between them and a typical aluminum wheel.

Nobody said that only CF wheels can suffer from barrel grooves. CF does "take hits far better and will not yield, crack, or break for a given load that yields and damages an Al wheel" in general and assuming they were designed to perform this way. And since cabon monocoque keeps getting mentioned...

https://jalopnik.com/heres-how-carbon-fiber-absorbs-crash-energy-in-slow-mot-1578920092

CF is very strong when designed for a specific purpose and takes certain loads very well with respect to deformity or failure.

https://i.kinja-img.com/gawker-medi...ogressive,q_80,w_800/qumrdno5nqlspmwvuats.mp4

Step outside the intended window and CF doesn't perform so well.

https://i.kinja-img.com/gawker-medi...ogressive,q_80,w_800/o1oxmtbzkxdrr7f4giqc.mp4

And since everyone else has included areas of use beyond the GT350/GT500 wheel and with respect to the statement that "CF wheels don't explode or shatter - tell these guys that. CF "wheels" can and have both exploded and shattered. All inclusive statements opened the door here...



Ouch.

It's highly fallacious to compare the characteristics of a crash box to how a CF monocoque or wheels yield.

Composites are highly complex and strength, stiffness, energy dispersion can all be engineered to fail at a given load, load path, and way, depending on the resins, fiber characteristics and how those fibers are laid.

Crash boxes are designed to disintegrate and disperse energy over a given distance as evenly as possible. That is their function. If all carbon acted this way, no one would ever make a monocoque for fighter pilots, boats, race cars, etc...

Competitive bicycle wheels constantly push the limits of weight reduction and meet the bare minimum to hold the rider up during vertical load paths. I won a race with Sir Chris Hoy a few weeks ago (6x gold metal Olympic cyclist) and he told me they can collapse their CF wheels by picking them up by the spoke, and they can collapse from a pebble hitting the spikes perpendicularly. When every gram counts to set records, that's how those wheels are designed. Now for the Tour De France, there are far more hazards on public roads than on circuit tracks, so the wheels are heavier and more durable to handle the varying conditions. It all depends on how it's designed and what it's for.

The material properties of composites and the ways strength, stiffness, and how a component yields can be engineered in ways metals can only dream of.

If you are really interested in learning more, I urge you to read the MotoIQ article I wrote. It covers most of your concerns.

Now the advantage you talk about (1 second). Is that able to be felt by the above average driver or only one of your caliber?
It seems that if we are really talking about flexing of wheels that only a true Pro could feel and use the difference.

My original jab at carbon wheels was meant to be as someone that tracks their car regularly will not want carbon wheels as they are too prohibitive and when you track cars you need lots of wheels and tires. It was NOT against their performance gain.

Before this thread became a Carbon wheel debate, it was meant to be about actual track performance. As you would know best about the track performance of these cars, I would love to hear anything you are allowed to say

Anyone can feel the increased stiffness and reduced gyroscopic effect in the steering wheel at 45mph on the street. You don't need to be a pro or able to drive fast on a track to feel the benefits of CF wheels.

If you crack or break a carbon wheel, you probably have far bigger problems from that impact (need a new chassis). You're not going to crack a wheel from dropping tires off a curb like you might with an Al wheel, which is very common in cheap (or even expensive big name) lightweight wheels. Lighter Al wheels are outright weaker than heavier wheels of similar design.

Al wheels are slower than carbon

I URGE EVERYONE commenting or concerned about CF wheels to READ THE MOTOIQ ARTICLE. It covers and addresses all of these concerns.

 

[Epiphany]

Hasn’t anyone seen all the gt350R wheel failures from pothole impact? So don’t fret too much over cf wheels. Way better off with forged wheels. Retired plastics engineer 30 + years with the biggest petrochemical companies in the world.They make the plastics you all use. And remember while plastics are great(no modern world without them) they have limits. And yeah I’ll kick this hornets nest.just my professional 2 cents.

Well put.

1) It's highly fallacious to compare the characteristics of a crash box to how a CF monocoque or wheels yield.
Crash boxes are designed to disintegrate and disperse energy over a given distance as evenly as possible. That is their function. If all carbon acted this way, no one would ever make a monocoque for fighter pilots, boats, race cars, etc...

2) Competitive bicycle wheels constantly push the limits of weight reduction and meet the bare minimum to hold the rider up during vertical load paths. It all depends on how it's designed and what it's for.

3) Anyone can feel the increased stiffness and reduced gyroscopic effect in the steering wheel at 45mph on the street. You don't need to be a pro or able to drive fast on a track to feel the benefits of CF wheels.

4) If you crack or break a carbon wheel, you probably have far bigger problems from that impact (need a new chassis).

I think everyone appreciate your posts, me included. That said, I don't agree with every comment.

1) The point was to provide perspective, in general, as to crash testing framework done in CF. Regardless of intent, the GIF shows how CF can react whether intended or otherwise.

2) The point to the cycling video was in response to the comment that CF wheels don't explode, etc.

3) I wouldn't say anyone. Far too all inclusive and makes a rather grand assumption. You can, others in your circle can, as well as people outside of racing. But many haven't a clue.

4) I don't agree with this statement at all. On its face it would seem logical but the reality is that isn't the case.

Large pothole, meet GT350R CF wheel...

(Two different time points from the same video below)

 

[BillyJRacing]

Hasn’t anyone seen all the gt350R wheel failures from pothole impact? So don’t fret too much over cf wheels. Way better off with forged wheels. Retired plastics engineer 30 + years with the biggest petrochemical companies in the world.They make the plastics you all use. And remember while plastics are great(no modern world without them) they have limits. And yeah I’ll kick this hornets nest.just my professional 2 cents.

Most failure modes for carbon fiber is in the resins (which can crack), but are also easily repaired.

Carbon Fiber's fatigue cycle (and the resin fatigue cycle) is far superior to metals. CF (& it's resin) is also far superior in terms of corrosion, and the new UV stable resins are so much better that you now see more exposed carbon in production cars (and Carbon Revolution's wheels for the Ford GT, GT500, Ferrari Pista, etc...). Because of the durability of the fatigue cycles and corrosion, the military uses composites for everything from airframes, rotor blades, and structural components. It's not just because of reduced weight and far superior strength:weight ratios

Repairs suck, but CF wheels can be repaired to like-new levels of performance and strength, where an Al wheel subjected to the same "Grand Canyon"-sized pothole would likely be unrepairable. I'm pretty sure the repair costs of those wheels are less than replacement costs of a quality performance Aluminum wheel. So advantage - still Carbon Wheels.

I think everyone appreciate your posts, me included. That said, I don't agree with every comment.

1) The point was to provide perspective, in general, as to crash testing framework done in CF. Regardless of intent, the GIF shows how CF can react whether intended or otherwise.

2) The point to the cycling video was in response to the comment that CF wheels don't explode, etc.

3) I wouldn't say anyone. Far too all inclusive and makes a rather grand assumption. You can, others in your circle can, as well as people outside of racing. But many haven't a clue.

4) I don't agree with this statement at all. On its face it would seem logical but the reality is that isn't the case.

Large pothole, meet GT350R CF wheel...

1) It's still highly erroneous to draw conclusions to a composite structure DESIGNED to disperse energy (crash box) to another composite structure that's designed to remain intact (carbon monocoque or carbon wheel).

2) Already addressed

3) Please read the MotoIQ article. To put that comment in context (from the article):

"I’m sure pretty much anyone who enjoys driving would be able to tell a difference."
"You’ll notice the difference and improvement in steering feel due to the reduced gyroscopic effect when simply turning the wheel at speeds above 20mph."

I wrote the article with everything in context so I wouldn't have to say the same thing over and over and and make a comment out of context.

4) To expand on item "3" - I should have put the "crack or break" into the context of "Catastrophic damage". The 3 GT350R wheels from that video are easily repairable (composites are easily reparable, especially rim lips -which don't effect the wheel structure much at all). If that guy gives up on the wheels, a savvy person could easily reach out to him and pick them up for a steal, send them out for a repair, and then will have some of the best wheels ever made on their GT350.

Read the article. Carbon wheels are repairable.

Any new technology will have growing pains and CF wheels is no different. CF chassis were also considered dangerous when they first came out, but are now the standard that everyone uses in motorsport and production cars. The same goes for the military. But I cover all of this in the article. ;)

 

[Epiphany]

I'm pretty sure the repair costs of those wheels are less than replacement costs of a quality performance Aluminum wheel. So advantage - still Carbon Wheels.

1) It's still highly erroneous to draw conclusions to a composite structure DESIGNED to disperse energy (crash box) to another composite structure that's designed to remain intact (carbon monocoque or carbon wheel).

2) Already addressed

3) Please read the MotoIQ article. To put that comment in context (from the article):

"I’m sure pretty much anyone who enjoys driving would be able to tell a difference."
"You’ll notice the difference and improvement in steering feel due to the reduced gyroscopic effect when simply turning the wheel at speeds above 20mph."

I wrote the article with everything in context so I wouldn't have to say the same thing over and over and and make a comment out of context.

4) To expand on item "3" - I should have put the "crack or break" into the context of "Catastrophic damage". The 3 GT350R wheels from that video are easily repairable (composites are easily reparable, especially rim lips -which don't effect the wheel structure much at all). If that guy gives up on the wheels, a savvy person could easily reach out to him and pick them up for a steal, send them out for a repair, and then will have some of the best wheels ever made on their GT350.

Read the article. Carbon wheels are repairable.

Any new technology will have growing pains and CF wheels is no different. CF chassis were also considered dangerous when they first came out, but are now the standard that everyone uses in motorsport and production cars. The same goes for the military. But I cover all of this in the article. ;)

Those wheels appear to be damaged beyond cosmetics. The weave looks to be torn where the Von Mises stresses can be the highest - not good and I have a sense that Ford corporate lawyers would agree. The wheels damaged in that video are likely to not perform as well as a new CR CF wheel in both destructive and durability testing.

1) There was no conclusion drawn. That's an incorrect inference. I stated why the video was linked and was pretty clear about it.

2) Avoiding absolutes goes a long way when making a point that can or will be refuted later.

3) You give the general driving far too much credit. I laud you for your positive outlook but I firmly believe the reality is in direct contrast.

4) Repairable in what context? Cosmetic or structural? Those wheels were clearly damaged in a way that the underlying weave was torn at or near the fillet for a given spoke. It couldn't be in a worse spot. And based on the costs some have forwarded for rather light cosmetic damage of CR's CF wheels, I'll stick to a quality forging given the monies we are talking about with respect to repair.

Out of curiosity, and a very general question, but what do you think it would cost to repair (to a standard that both Ford and CR would approve of) even one of the wheels in that video? I sense that your number is far less than what most anyone would be quoted.

 

[BillyJRacing]

Those wheels appear to be damaged beyond cosmetics. The weave looks to be torn where the Von Mises stresses can be the highest - not good and I have a sense that Ford corporate lawyers would agree. The wheels damaged in that video are likely to not perform as well as a new CR CF wheel in both destructive and durability testing.

Some are superficial cosmetics, others have damaged the fibers deeper into the rim lip that have yielded - but in areas that are not crucial to the load paths a wheel sees and has to resist. All of which are likely repairable.

1) There was no conclusion drawn. That's an incorrect inference. I stated why the video was linked and was pretty clear about it.

There were conclusions implied if not drawn. Your persistently negative comments and spread of misinformation makes me wonder what your motives are. Are you the owner in that video? Do you own or work for any wheel manufacturer?

3) You give the general driving far too much credit. I laud you for your positive outlook but I firmly believe the reality is in direct contrast.

Those are my beliefs based off my background from development driving to coaching (the last 14 years) varying levels of talent from the general population on up to Nascar drivers & LeMans winners.

4) Repairable in what context? Cosmetic or structural? Those wheels were clearly damaged in a way that the underlying weave was torn at or near the fillet for a given spoke. It couldn't be in a worse spot. And based on the costs some have forwarded for rather light cosmetic damage of CR's CF wheels, I'll stick to a quality forging given the monies we are talking about with respect to repair.

Out of curiosity, and a very general question, but what do you think it would cost to repair (to a standard that both Ford and CR would approve of) even one of the wheels in that video? I sense that your number is far less than what most anyone would be quoted.

Both. The 'structural' damage is not in crucial areas of the wheel. Based off of how the wheel is designed and where the crack is at the spoke, its still probably not a concern until Spyder looks at it. Cost wise, you can email the pics to Spyder Composites for a quote.


Conversations like these are the reason I try to stay off forums. I'm more than happy to dispel myths and help people who have genuine questions and concerns, but i'm not interested in discussing what has been covered in the article, or willing to enter a pissing contest with someone who has nefarious reasons, or who want's to perpetually demonstrate their superior knowledge with a closed mind.

 

[svttim]

Interesting conversation. I just took off my CF wheels and put on alluminim wheels on for the street. I will use my CF wheels for tracking. I expected to feel nothing at low speeds. I immediately noticed the sreering was heavier. I hemmed and hawed how to use my CF wheels but, considering the expertise of at least one of the people here, Im going to track my CFs. Sorry to the R's are not all that group

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