Alchemist Unveils Zirconium Disc Brake Road Bike Wheels – Light, Stiff & Asymmetrically Aerodynamic

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Alchemist has shown us some pretty wild looking wheels for mountain bikes in the past, and now they’re applying their unique take to the road market with an astonishingly lightweight set of disc brake-only clinchers.

The new Zirconium wheels use an asymmetric rim profile to balance spoke tension evenly from side to side. The 2mm offset also improves dish, and reinforced spoke nipple beds increase strength, allowing them to use higher tension for a stiffer wheel. All that, and the high modulus carbon fiber rim weighs in at just 315 grams!

As usual, their hubs are a work of art, mixing carbon and alloy with their signature angles and flares on the spoke and disc flanges. What’s unusual are the aero claims…

alchemist zirconium lightweight aero disc brake road bike wheels

Both wheels use 24 straight pull CX Ray spokes. The front wheel gets 2-cross lacing on the disc side and radial on the drive side.

alchemist zirconium lightweight aero disc brake road bike wheels

The rear gets 2-cross lacing on both sides.

alchemist zirconium lightweight aero disc brake road bike wheels

The spoke holes are angled and offset, helping hem build a strong wheel. We’ve become accustomed to such designs on mountain Joe rims where aerodynamics matter less, but on the road, things have been stubbornly symmetric when it comes to aero shapes.

alchemist zirconium lightweight aero disc brake road bike wheels

Alchemist’s solution was a NACA M18 profile, which they say helps equalize the pressures on each side of the wheel as best as possible, balancing aerodynamics and crosswind stability with the overall wheel design requirements of disc brakes. The image on the left shows a standard aero rim, the center is what happens when morphing that standard shape to an asymmetric one, and the left image is their design.

The best part? Even if aerodynamics aren’t your top concern, the 1,197g wheel set weight makes them appealing to climbers that want less rotational mass on the way up with the stronger braking discs provide on the way down. And with a 20mm internal width (24mm external) and good all around 40mm depth, these hoops check a lot of the right boxes.

The 40mm depth is where the wheels got their name, as Zirconium is number 40 on the periodic table.

AlchemistBikes.com

Comments

jm - 08/25/14 - 8:14am

“As usual, their hubs are a work of art, mixing carbon and alloy with their signature angles ”
Really? I was hoping for something unique, not to see old spinergy hub design having a renascence.

Should’ve put some rotors on dem wheels to drive the DISC thing home.

Ghost Rider - 08/25/14 - 9:20am

Diggin’ that black n’ orange color scheme, too.

deboat - 08/25/14 - 9:50am

asse nipples…. Really??

gringo - 08/25/14 - 11:41am

They do look nice, but what suprises me is almost weekly we see new wheels from who knows where. I am hoping all these little guys don’t lose their shirts thinking there is money to be made in bikes.

As I was taught way back when: how do you make a million in the bike biz? Start with two million.

Dude - 08/25/14 - 12:12pm

Just to channel Jobst Brandt… higher spoke tension does not equal a stiffer wheel.

But anyways, good on them for jumping in and trying to do something different. Not your usual slapped-together-from-china look.

Dustin - 08/25/14 - 12:15pm

A few thoughts:
Higher spoke tension does not make a stiffer wheel. Period. Also, 120kgf of tension is hardly “high” – that’s typical actually.

And radial lacing on a front disc wheel is a 100% fashion choice. Not performance, and certainly not safety. Radial lacing cannot transmit the torque from braking, so that wheel is relying on only 6 spokes to transmit braking forces. Using radial on one side instead of two-cross all around saves about 2.5g. For perspective, a penny weighs about 2.5g. So they decided that a cool look, and 2.5g weight savings, was worth havjg only half as many spokes doing the work of breaking.

Stupid, stupid, stupid.

But hey, they look neat!

turbojet megafred - 08/25/14 - 12:43pm

To respond to Dustin, the radial lacing on the front hub is a good call for a few reasons. First, the radial spokes have a steeper angle from the hub flange to the rim, making the wheel stiffer laterally. This is important as disc brake front hubs lose a lot of their flange width to the rotor mount vs. rim brake hubs. Second, the light weight carbon center piece is probably just glued into the hub, so transferring braking torque across it to the opposite flange is a bad idea. The radial spokes make for a stiffer wheel, and allow for the carbon centers which reduce weight. If you’d prefer a flexy wheel that weighs more, there are plenty of options out there.

Michael - 08/25/14 - 1:48pm

The stretched first image initially gave me the impression that this was to be the biopace of aero wheels.

Morgan - 08/25/14 - 1:51pm

Cool rim shape, but how does it perform at wind directions other than 0deg? I’m guessing it goes a bit squirrelly from there.

Dork - 08/25/14 - 1:59pm

Turbojet megafred is on the money regarding the lateral support granted by radial lacing, and the non-issue of opposite-disc lacing concerns, as far as I’m interested. If more folks read into what’s really going on with wheels, or trust any wheelbuilders worth their salt, things will be a lot less mysterious.

It’s worth mis-quoting: “worth havjg only half as [...] Stupid, stupid, stupid!”

Tyler Benedict - 08/25/14 - 2:30pm

Michael – I posted from my phone and skewed the image sizing, it’s been fixed. Thanks.

Dude - 08/25/14 - 2:48pm

Radial only gives you a slightly steeper bracing angle but completely eliminates the braking torque transfer. So the additional wheel stiffness gained is minimal, but you’ve doubled the braking loads on the spokes on the other half of the wheel.

Loki - 08/25/14 - 2:48pm

Aargh, … and then to misquote Jobst Brandt, shame on you!

He was talking about spokes in an accepted ‘normal’ range. Think spokes don’t affect stiffness? Loosen all your spoke by 40kgf and check back in with your findings!

Also, when you use the word wheel stiffness, do you mean torsional, radial or lateral ?

Regardless of our assumptions and prejudices wheels are a system and can only be judged as a system: isolating spoke tension, or hub angle, or axle stiffness is exactly that, isolated judgement.

Dude - 08/25/14 - 3:07pm

http://sheldonbrown.com/rinard/wheel/index.htm

Someone did pretty much just that.

Loki - 08/25/14 - 4:57pm

Not really intending a discussion of wheel building lore but , with all respect to the venerable Brandt and Brown, the tests are useful,interesting, but dated (RevX!) and by his own admission are only focused on narrow lateral stiffness considerations, which have little import on the original comments about disc brakes and radial lacing.

I agree that you’ve double the braking loads on the spokes on the other half of the wheel; their point is that they’re strong enough to deal with those loads.

TJ - 08/25/14 - 5:10pm

Rider weight limit?

Dude - 08/25/14 - 5:32pm

@Loki lateral, radial and torsional stiffness are all unaffected by spoke tension (as long as the spokes aren’t slack) because the same material properties are in play in each case. The Damon Rinard test may be old but it’s just experimentally demonstrating what is already known about spoke elasticity.

The wheel may indeed be strong enough, and without doing the math I have no idea how much the spokes are being stressed under heavy braking. That design element doesn’t irk me much beyond the aesthetic, as I assume *someone* bothered to run the numbers, though I wouldn’t personally pick a potentially weak lacing pattern. Then again… the bike industry doesn’t always engage in “real” engineering (cough cough Mavic R-Sys cough cough).

greg - 08/25/14 - 10:52pm

radial lacing on its own barely saves any weight. but with straight pull spokes, the hub shell for the radial side can be much lighter (“much” being relative).
that said, if i was doing this, id opt for 2:1 lacing on the front, and a super slim center hub shell section. and centerlock.

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