Carbon wheels coming soon?

[samoht]

I was listening to Sam Moores' podcast talking to the head of Dymag wheels, and the story he was telling is that carbon fibre wheels are currently scaling up from ludicrously expensive niche products to become a plausible high-end option for people who are really keen to save weight. As production volume increases, costs can come down by a factor of ten. It sounded like their rival company Carbon Revolution is much further down this path, doing full carbon wheels for Ford, Corvette, Ferrari, Range Rover and others. Dymag meanwhile do hybrid wheels, with a carbon fibre outer barrel and a metal centre, found on the BAC Mono and also offered as partnerships by other wheel companies.

Wheels are the absolute best place to lose weight, as you lose overall weight, unsprung weight for the suspension to damp, and rotating weight to spin up and down as you change speed, and 40%+ weight saving compared to a 'normal' aluminium wheel seems very significant (especially as wheels get bigger and bigger... sigh).

Does anyone have experience of carbon fibre wheels? Any noticeable pros or cons? Are we on the brink of them becoming mainstream?

I have to admit I'd love to get some although it'll probably be a while before they're in my budget, and so far they seem to be mostly offered as OEM fitment rather than through the aftermarket.



https://www.carbonrev.com/wheels/
https://dymag.com/auto/

[HiAsAKite]

I'd be interested to know how tolerant they are to cracking on "normal" (aka potholed) road use...


Its one thing using them in scenarios where they could be subject to regular inspection (eg after each race for a race car using specialist xray equipment if needed).. another thing on road cars which at best are inspected once per year

Catastrophic wheel failure on road cars would be very, very bad.


I'm presuming this factored in the design somehow.

[hidetheelephants]

Composite wheels, such an innovation they were available in 1970.

[bimsb6]

Dymag and bst have been making carbon wheels for bikes for years .

[dbdb]

I knew a guy years ago who owned a Citroen SM with the composite wheels - they looked fabulous on the car.

[richhead]

apart from the bling factor, why would you, mag wheels have been around for an age, and are not much heavier, but they do need proper checking regularly, im talking crack testing, not sure they would be worth the money, just skip the burger at lunch

[Terminator X]

I'm a fan.



TX.

[Nicks90]

richhead said:

apart from the bling factor, why would you, mag wheels have been around for an age, and are not much heavier, but they do need proper checking regularly, im talking crack testing, not sure they would be worth the money, just skip the burger at lunch

Exactly. If your that concerned with weight, rip out the leccy windows, Aircon, central locking and all the seats / carpets. And I bet the stereo and speakers weigh a fair bit too

[otolith]

Nicks90 said:

Exactly. If your that concerned with weight, rip out the leccy windows, Aircon, central locking and all the seats / carpets. And I bet the stereo and speakers weigh a fair bit too

Unsprung, rotating mass, though.

[Mark83]

HiAsAKite said:

I'd be interested to know how tolerant they are to cracking on "normal" (aka potholed) road use...


Its one thing using them in scenarios where they could be subject to regular inspection (eg after each race for a race car using specialist xray equipment if needed).. another thing on road cars which at best are inspected once per year

Catastrophic wheel failure on road cars would be very, very bad.

I'm presuming this factored in the design somehow.

Not a direct comparison but I've been riding carbon wheels on my road bike since 2017. They're tough, hitting potholes etc. and not even out of true let alone a failure. My current set, latest design by Enve, come with a no rider weight limit and a lifetime warranty.

[IMI A]

There is a very noticeable difference on SWMBO's turbo s with her OEM carbon wheels. The car is much more responsive on them dynamically. Acceleration ,direction changes etc are markedly improved too. Having said that I'd not have them on my own car I'd be too nervous about kerbing them

[Baldchap]

Nicks90 said:

richhead said:

apart from the bling factor, why would you, mag wheels have been around for an age, and are not much heavier, but they do need proper checking regularly, im talking crack testing, not sure they would be worth the money, just skip the burger at lunch

Exactly. If your that concerned with weight, rip out the leccy windows, Aircon, central locking and all the seats / carpets. And I bet the stereo and speakers weigh a fair bit too

Wheel change makes for a meaningful change where it matters. Ripping out creature comforts makes the car worse to use.

[samoht]

Nicks90 said:

Exactly. If your that concerned with weight, rip out the leccy windows, Aircon, central locking and all the seats / carpets. And I bet the stereo and speakers weigh a fair bit too

You're right to question how much difference a weight saving makes, with things like carbon fibre body panels a saving of a few kg is small as a fraction of the whole car, unless it's part of a holistic weight reduction strategy. In this case saving perhaps 15-20kg on a set of four wheels is 1% of a 1500kg car.

However it's not just the overall mass that matters. The wheels, tyres and suspension have to bump up and down to follow the shape of the road, and the lighter they are the better. This unsprung weight can total about a tenth of the car's overall, so say 150kg. So saving 15kg+ from that will make a real difference.

The wheels are also rotating, so have to be spun up to speed and down again when you stop and start; the wheel and tyre is like a flywheel, so reducing 40% of the wheel (probably about 20% of the wheel + tyre together) is again significant.

Finally the front wheels have to turn when you steer; consider that the gyroscopic effect (resistance to turning of a spinning wheel) on a bicycle is a big part of how you keep one upright, and how much heavier and faster car wheels are, then mass reduction here is also significant.

So while the saving carbon fibre wheels offer isn't that significant as part of the car's overall total mass, as part of the unsprung, rotating and turning mass it's quite significant, and the sort of difference that I can easily believe a driver would feel.

[Olivera]

samoht said:

So while the saving carbon fibre wheels offer isn't that significant as part of the car's overall total mass, as part of the unsprung, rotating and turning mass it's quite significant, and the sort of difference that I can easily believe a driver would feel.

Yes but for a road car there are other considerations:

1) Strong enough to absorb potholes and impacts without bending/cracking/failing
2) Maintainable, i.e. can be easily refurbed or touched in after kerbing or other damage

UK roads are IMO just not suited to carbon wheels. I'd even be nervous about trusting them with your average tyre fitter, given the cost and repair issues - they would have to be absolutely meticulous with each wheel on the tyre fitting machine.

[Dave Hedgehog]

Gordon Murray is against them on road cars because damage is not always visible and the catastrophic way they fail

That's good enough for me