Wheel STIFFNESS matters! -We test Carbon Revolution's Carbon Fiber GT350R wheels vs AL wheels.

[BillyJRacing]

The lug area and cross section can easily be thickened and reinforced for motorsport use and the abuses of air guns (if needed). I also have a bunch of other pics and confidential stuff that I can't post.

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[Next Phase]

I get that CF wheels are "stronger." As to being more durable...I think it fair to say that concern for most is cost to purchase/cost to repair is quite a bit higher than the typical Forgeline wheel along with it being difficult to justify those performance increases given that most R model Mustangs or Ford GT's aren't used in a race environment exclusively across the board.

To my point about how I see them handled in Continental.....I'm sure the guys that change them that have to twist and throw them over the wall at times would welcome a lighter wheel as would the drivers. But their purchase and use would absolutely add additional expense. I've watched how various teams prep their wheels and at times, cringed. A cordless drill with a countersunk bit is used to dress or "freshen up" the tapered area of the lug seat and to quickly remove the glue used to hold the lugs to the wheel. CR's CF wheels use a 6061-T6 male into a female insert here (on all their wheels) to in effect, sandwich the fiber such that you arent having fiber touch either the wheel hub or the lug itself. The last thing you'd want to do is to compromise the insert on a CF wheel. In this regard, Forgelines look to be far less costly and easily stand up to the rigors and abuse in a rather extreme race environment at reasonable cost.

Maybe in 10 years or so they'll be as common as a typical aluminum wheel on a street vehicle. But for now they are way too exotic and owners that have had to deal with any issues can relate to the nightmare situations associated with them. Witness the thread down just a few posts from this one.

https://www.mustang6g.com/forums/threads/gt350-r-carbon-fiber-wheel-failure.104830/

Billy, I had a great conversation with Kyle Marcelli at VIR and your name came up. I could see him getting rated the way you did and getting bumped from Continental in the future. Is there any chance, given the current system, that you'd ever be back in GS (for example)?

Getting a vendor to help fix the wheel was a hassle, but Carbon Revolutions referred me to Spyder. I did get my wheel back and had it on the track this past weekend. (Keep in mind, my CF wheels never lost air while on track while hot; they lost air when sitting for weeks cold). Kudos to CR for their follow up with me. I'm really impressed with that company after dealing with Ford.

One thing I can add is that there was no seat of the pants difference from running the CF wheels on MP4S tires versus my Cup 2's on heavier BC Forged wheels (square set up). The MP4S howled at the limit obviously and got a little greasy towards the end of my sessions... The CF wheels on Cup 2's make the car feel 500 lbs lighter. I don't have any data logging of my sessions, but I'll make sure to compare in my upcoming events.

Are the CF wheels worth the price of admission? That's a personal decision. For an amateur HPDE track rat like me? Not really... but they are fun to play with.

 

[BillyJRacing]

Getting a vendor to help fix the wheel was a hassle, but Carbon Revolutions referred me to Spyder. I did get my wheel back and had it on the track this past weekend. (Keep in mind, my CF wheels never lost air while on track while hot; they lost air when sitting for weeks cold). Kudos to CR for their follow up with me. I'm really impressed with that company after dealing with Ford.

One thing I can add is that there was no seat of the pants difference from running the CF wheels on MP4S tires versus my Cup 2's on heavier BC Forged wheels (square set up). The MP4S howled at the limit obviously and got a little greasy towards the end of my sessions... The CF wheels on Cup 2's make the car feel 500 lbs lighter. I don't have any data logging of my sessions, but I'll make sure to compare in my upcoming events.

Are the CF wheels worth the price of admission? That's a personal decision. For an amateur HPDE track rat like me? Not really... but they are fun to play with.

PS4S & Cup2s are significantly different tires in terms of tread depth, stiffness, construction, grip, etc.. stagger vs non stagger influences grip, feel, handling, balance as well. Same goes for tire width if you don't run the same size tires.

The performance of the Cup2 over PS4S is probably greater than the improvement of the carbon wheels unless your BC wheels are complete junk.

Did you back to back them on the track the same day?

 

[Next Phase]

PS4S & Cup2s are significantly different tires in terms of tread depth, stiffness, construction, grip, etc.. stagger vs non stagger influences grip, feel, handling, balance as well. Same goes for tire width if you don't run the same size tires.


Did you back to back them on the track the same day?

That's why I was so surprised on how they felt... the MP4S were brand new (ran them on Sunday) and the Cup 2's on Saturday were used on a previous track day. I agree with "The performance of the Cup2 over PS4S is probably greater than the improvement of the carbon wheels." Just surprised that there wasn't a bigger difference in feel. I'm sure I was running quicker times in the Cup 2's, but the temps were also 20 degrees cooler on Sunday with the MP4S.

 

[BillyJRacing]

That's why I was so surprised on how they felt... the MP4S were brand new (ran them on Sunday) and the Cup 2's on Saturday were used on a previous track day. I agree with "The performance of the Cup2 over PS4S is probably greater than the improvement of the carbon wheels." Just surprised that there wasn't a bigger difference in feel. I'm sure I was running quicker times in the Cup 2's, but the temps were also 20 degrees cooler on Sunday with the MP4S.

Give the article a read when you get a chance.

During a given day, track conditions can change and slow down by well over 1 second per lap. A 20-degree cooler day would be even more so and would help keep the PS4S in its operating window better. It's impossible to draw any conclusions when comparing two different wheels on two different tires on two drastically different days.

If you have the ability to back to back both setups on the same day, you may feel steering effort and precision differences even with drastically different tires. It would be extremely obvious if both wheels had the same tires.

 

[Zitrosounds]

Looks like you failed to understand what i wrote. You are missing the point. Sure its great, R comes with carbon wheels. Im not arguing of its superior stats. The argument here is choosing carbon wheels vs forged aluminum wheels as a aftermarket product.
And the article leaves out 2 of the biggest problem carbon wheels provide, which are cost and maintenance issue.
Also someone else pointed out forgeline wheels have same strength/stiffness as oem porsche wheels. Sure they may have, although quality and design of the aluminum wheel may have differences. Also weight of forgeline wheels are much lighter than oem Porsche wheels. Could that have closed 0.16 sec difference gap? Could be.
You call me close minded? You seem to be the one having hard time critically analyzing whats presented to you. Tell me why the article doesnt emphasize on avg lap time difference, but instead largest delta on a single lap. Also tell me why they decided to use oem porsche wheels that weight more than high quality aftermarket forged wheels?
Maybe instead of just agreeing what you read, do some critical thinking for yourself.
And no, carbon wheels arent worth $12k price tag.

YAWWWWWN!

 

[BillyJRacing]

I couldn't mention this at the time of writing the article but now it's public:

Production increasing 15X:

https://www.motorauthority.com/news...to-supply-150000-carbon-fiber-wheels-annually

 

[Darkane]

Amazing, not bad for a guy who started making carbon wheels as a side hobby.

He hails from a small town in Saskatchewan, Canada. He was at my local Honda dealer with a modified 350R inquiring about a Civic Type R.

Nice!

 

[Epiphany]

The lug area and cross section can easily be thickened and reinforced for motorsport use and the abuses of air guns (if needed). I also have a bunch of other pics and confidential stuff that I can't post.

"Could" is one thing. The question is, why hasn't it happened? I've studied CR's designs in detail as well.

This is where Carbon Revolution wheels is another game-changer. The technology is new and currently banned in almost all forms of motorsport. If a carbon wheel were to be used on a prototype or GT3 race car, unsprung weight would go down and stiffness would be greatly increased allowing teams to run less static camber.

And why are CF wheels not allowed by various sanctioning bodies across the motorsports spectrum? If you exclude the cost argument (costs can be a bit exorbitant here) and focus strictly on the merits of the wheel, why wouldn't teams want to use them?

Regarding the inserts and thinking it through, the nice thing is that the inserts could readily be changed by removing the retaining clip on the inside of the wheel and slipping in a new one.

Are the CF wheels worth the price of admission?....For an amateur HPDE track rat like me? Not really... but they are fun to play with.

This is where CR gets stuck in a catch-22. In order to be in a position to better take advantage of economies of scale, a much larger infrastructure or capital investment needs to take place (looks like CR is indeed making inroads here). It is going to take time before prices truly trickle downward far enough for them to be a viable alternative for many. Quite simply, we're not there yet.

I couldn't mention this at the time of writing the article but now it's public:

Production increasing 15X:

https://www.motorauthority.com/news...to-supply-150000-carbon-fiber-wheels-annually

I saw a few articles along these lines pop up in the last couple of days and thought about the creation of this thread. I don't see a date included with the article. When was it written?

 

[BillyJRacing]

"Could" is one thing. The question is, why hasn't it happened? I've studied CR's designs in detail as well.

I guess you missed the "IF NEEDED" part. Have you done FEA analysis on the wheels or tested the demands and loading on the lug seats to determine the necessary cross sectional area for Carbon Revolution's design?

If the current designs meet or exceed all of the OEM's durability requirements, why change something for the sake of changing it? IF the needs are different for motorsports use, i'm sure they would adapt the design accordingly for a motorsport-specific wheel.

And why are CF wheels not allowed by various sanctioning bodies across the motorsports spectrum? If you exclude the cost argument (costs can be a bit exorbitant here) and focus strictly on the merits of the wheel, why wouldn't teams want to use them?

It's mentioned in the article. Even at the current price, race teams would absolutely pay that premium for those performance gains. It would be a no-brainer and widespread if allowed.

In addition to what was said in the article, sanctioning bodies often do counter-productive things in the name of 'reducing costs' that usually end up increasing operating costs for race teams.

I saw a few articles along these lines pop up in the last couple of days and thought about the creation of this thread. I don't see a date included with the article. When was it written?

It went live Monday and as mentioned in the original post, it's been a year in progress.

 

[JAJ]

...The stock, heavy GT350 wheel is much stiffer than the majority of aftermarket 'lightweight' wheels. That's why it's common to see people who switch to those lightweight wheels then say that "This car (GT350) needs 2.5, 3, 3.5, 4* of negative camber and push GT350 (and even R) owners to try to adopt those levels of camber that's unnecessary with a stiffer wheel...

Now, that's fascinating. I'm running OEM GT350 aluminum rims for track days with 30# 11" OEM rears in a square configuration. I've set my front camber at -1.8 degrees and tire wear has been remarkably even. The 305/30x19 Conti's in the photo have 507 track miles and 19 heat cycles running on OEM 11" rims - they're done for track work but they're in good shape otherwise.

Every time I read about "this car needs 2.5+ degrees of camber" my response is "what for?"

 

[gixxersixxerman]

Ive never used carbon wheels on a car. but ive used them in the motorcycle world. My street bikes usually got Marchesini forged wheels. the race bike me and a friend had the same but he found a company while we were at the Laguna Moto GP race called rotobox. they made carbon wheel... night and day.. all i could say.. night and day.. I am a believer in carbon wheels and sure they came a long way from back in 2011-12 when we first came across them. I do wish they wouldve tested the OEM wheels along with a set of proper lightweight race wheels just to see the comparisons. having all three would help with the speculations. I think we have a long ways to go before we see carbon on regular street cars but think we will get there.. If you thank about it, it wasnt that many decades ago they said aluminum wheels would never be mass produced on OEM cars. it was all steel wheels. aluminum wasnt "strong" enough wasnt "economical" cost too much. now its pretty standard..

 

[honeybadger]

Now, that's fascinating. I'm running OEM GT350 aluminum rims for track days with 30# 11" OEM rears in a square configuration. I've set my front camber at -1.8 degrees and tire wear has been remarkably even. The 305/30x19 Conti's in the photo have 507 track miles and 19 heat cycles running on OEM 11" rims - they're done for track work but they're in good shape otherwise.

Every time I read about "this car needs 2.5+ degrees of camber" my response is "what for?"

In my experience, it depends on the track, your driving style and level, and the setup on the rest of the car.

Here's my car on turn 12 at COTA. I was running -4.1 up front and -3.2 in the rear. As you can see, it's using every bit of camber I gave it.

I'd love to run a set of CF or even OEM non-r wheels back to back with these on my camber settings to get temps. It's too bad you're so far away now. We could've conducted a fun test!

 

[Epiphany]

I guess you missed the "IF NEEDED" part. Have you done FEA analysis on the wheels or tested the demands and loading on the lug seats to determine the necessary cross sectional area for Carbon Revolution's design?

I didn't miss the "IF NEEDED" part. To be clear, the mere suggestion was yours, not mine.

The lug area and cross section can easily be thickened and reinforced for motorsport use and the abuses of air guns (if needed).

Regarding any and all FEA analyses on these wheels and their respective hardware...my guess would be that you haven't done any and instead you rely on those that have. For that matter, so does the general public with each and every CF wheel that is out on the road. I'm a little shy of the resources of both Ford Motor Company as well as CR, so at this point I'm lagging in the virtual testing department. I'd love to see the data on any POF/destructive testing regarding the lug hardware or wheels themselves if you happen to have it and are able to share.

If the current designs meet or exceed all of the OEM's durability requirements, why change something for the sake of changing it? IF the needs are different for motorsports use, i'm sure they would adapt the design accordingly for a motorsport-specific wheel.

Not sure where you get anything about changing something simply for the sake of changing it. As far as IF the needs are different for motorsports use we aren't seeing it via Ford here in the US as neither the Continental/World Challenge GT4 cars or the race GT IMSA car are using them. I'd love to see CR test their best CF wheel in a 24hr race such as Le Mans or Daytona and see how they hold up.

It's mentioned in the article. Even at the current price, race teams would absolutely pay that premium for those performance gains. It would be a no-brainer and widespread if allowed.

I saw what was mentioned in the article. I'll ask around at the Continental GS finale if various teams would be alright paying the premium in order to run a CF wheel. Assuming CR did a run of 18" diameter wheels for the series (with the same thermal coating inside) do you think it fair to say the cost could be triple that of the Forgelines currently in use?

In addition to what was said in the article, sanctioning bodies often do counter-productive things in the name of 'reducing costs' that usually end up increasing operating costs for race teams.

The one thing about CF is that when it does yield it gets ugly fast. Think: shards. Something most any sanctioning body would prefer to avoid, no? A different failure mode than what you see in a typical aluminum or steel wheel. Compared to metals, when composites are fatigue loaded the density of interlaminar and intralaminar "micro cracks" multiplies as opposed to that of growth of a single crack. That can clearly be an issue with even the most basic means of evaluating - a visual inspection.

I have yet to see CR share any data on this type of testing. You see snippets of testing to a certain standard for road "worthiness" but nothing detailed. Completely understandable, as the aim is to draw interest as opposed to scaring anyone away. In the context of CF versus the typical aluminum wheel, carbon fiber can be woven to be very strong in a given plane but make no mistake, it does not go through plastic deformation like various metals do.

When CF fatigues it does so in three stages (successive). First up is matrix cracking. Second, local delamination as a result of matrix cracking. Finally, local delamination consolidates leading to failure. No doubt, CR has optimized critical elements such as strand choice(s), weave pattern, resin type and dispersion, along with cure rates/temperatures, that in the end make for a wheel that shouldn't fail catastrophically under what could generally be considered "normal" use. Their inclusion on certain production vehicles as of late is indeed impressive. But the fact that their use to date in motorsports has yet to become the norm is telling. There are plenty of other CF components used in racing, but not wheels. Talk about shards at created via impact at speed...



It went live Monday and as mentioned in the original post, it's been a year in progress.

Perfect timing then.

...

 

[TheDeadCow]

How many times was Carbon Revolution linked in this article?

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