Knight Composites 65mm deep aero road bike wheels

If you’re looking for the fastest aero wheels in the world, keep your scanners peeled for pro triathlete Heather Jackson aboard her new Knight Composites carbon fiber hoops this year.

Who’s Knight Composites? Oh, only the new brand intent on making the fastest bicycle wheels ever. Considering the massive interest in improved aerodynamics leading the development cycle at major brands like Mavic, Reynolds and ENVE (among many, many more), that’s a tall order.

So, they began by looking at the wheel as part of the whole bike because, well, you can’t have one without the other. Their testing revealed that the trailing edge had a more profound impact on overall aerodynamics than the leading edge…and by “trailing edge”, they’re mainly talking about the back half of the front wheel. So, they developed what they call Trailing Edge Aerodynamic Manipulation (TEAM) Tech.

But first, they had to assemble their team…

Chris Horner will ride Knight Composites wheels in 2015

After stints at Cobra making composite golf club shafts and starting Reynolds composites, Jim Pfeil was working at ENVE (when it was still EDGE) as operations manager and thought the company needed a global expert to come in and help the company grow. So Beverly Lucas interviewed and ended up becoming their global sales and marketing manager. She helped them make the name switch to ENVE to facilitate sales in other markets and have more ownership of their brand trademarks. She also helped start them down the road to developing an aero wheel by borrowing a little wind tunnel time from Felt while they were testing the DA tri bike. Then, while watching Grand Prix racing, she was inspired to reach out to that industry, which led to ENVE’s collaboration with Simon Smart.

From ENVE, Beverly moved to Australia work on different projects and learn that market, and Jim went on to work for Neilpryde. Fast forward a few years and she was back in Jim’s hometown of Bend, OR. They had coffee and decided that they should make an even faster wheel under a new brand. Thus, Knight Composites was born.

To round out the team, Kevin Quan (who’s worked on projects for Neilpryde, Diamondback, Parlee and others) is their lead engineer and company director. He oversees all designs and ensures their products are both accomplishing their own internal goals and meeting market demand.

Testing them under real world conditions will be Chris Horner, pictured above, and the rest of the Airgas Safeway development team, as well as pro triathlete Heather Jackson.

Knight Composites aero road bike wheels

That’s a good team, but what makes the wheels special?

“Basically, every wheel company in the past has looked at the leading edge of the rim as the most important part of the structure,” said Lucas. “That’s why some of them have even gone into tire production, so they could control that front-most leading edge. What Quan did was look at the trailing edge, which we could control much better.”

knight-composites-aero-rim-profile-drag-highlighted-leading-edge

The leading edge (aka “front”) of the wheel’s aerodynamics are largely dictated by the tire. Blue represents drag inducing turbulence caused by air separating from the rim instead of maintaining laminar flow.

The primary business of Quan’s studio thus far has been designing and engineering frames, the largest customer being Diamondback. They have a small wind tunnel in house that lets them test individual tubes, and it just so happens to fit a wheel. So, they started putting some of the best rated wheels in there to see what they could learn.

“(One brand) started with a two dimensional airfoil section onscreen, then converted to a full three-dimensional shape,” Quan said. “That let us get the full visualization of the airflow over a particular wheel section. We also reverse engineered a lot of our competitors’ products and threw things into CFD to figure out why others products were working or not.

“On the front half of the wheel, the tire really messes things up despite wheel engineers’ best efforts. What it comes down to is that the round shape of a tire just isn’t a good airfoil. When the air hits that tire, it’s going to separate, so you’d see more turbulence coming off the the front part of the wheel than on the rear. And that’s at even very low angles of yaw, around 5º wind angle.”

By changing the rim shape specifically to keep the air attached as long as possible on the trailing edge (aka "back") of the wheel, they could send air smoothly onto the frame.

By changing the rim shape specifically to keep the air attached as long as possible on the trailing edge (aka “back”) of the wheel, they could send air smoothly onto the frame.

“We never saw a lot of drag reduction at the front of the wheel,” he continued. “But when we flipped it around, we saw much better airflow.

“A lot of companies try to create symmetrical airfoils, making the leading edge the same as the rear. That makes the leading and trailing edge of the rims rather blunt. But we put a lot heavier emphasis on how the air hits the back half of the rim. We wanted to ensure that when the air left the trailing edge of the front wheel that it didn’t mess up the air hitting the frame. When the downtube is behind the tire, the rim/tire/frame acts as one giant airfoil.”

That thinking is what sets Knight Composite’s designs apart from the rest. Think of the fork bisecting the wheel. Everything behind it is what’s creating most of the drag. On the trailing edge (back half) of the wheel, the tire plays a much less disruptive role, especially since the wind transitions immediately onto the downtube.

Knight Composites 65mm deep aero road bike wheels

They’re using the same rim profile front and rear, though they’ll offer three different depths so you could run a deeper section rear if you want. As for aerodynamics improvements, though, Quan says you’re still getting the biggest bang for your buck by improving that trailing edge front transition into the frame. The rear wheel acts similarly, but plays a lesser role in overall aerodynamics. In most cases the front of the rear wheel is somewhat shielded by the seat tube, particularly on a TT/tri bike. But the exposed rear half of the wheel will perform better because of the design.

knight-composites-crosswind-lift-diagram

The other half of any aero wheel’s story is its stability in a cross wind, and Quan says their design also creates a much more stable wheel.

He says with almost any wheel, the air on the side facing the wind is going to remain attached. The trick is keeping the air attached on the other side of the rim, and that’s where stability comes in. Compared to many other aero rims, Knight’s profiles have a more of a gentle progression of shape from the front of the rim all the way to the tire.

“The wind hitting your body and your frame is going to try to push you to the side,” he says. “You’re still going to be blown sideways and the wheel can’t fix that. But, when the wind hits your wheel and fork and wants to wrench your steering, that’s where we can do something.

“The back half of the wheel has lift, and the front is pretty much stalled in anything past a 5º wind angle. Because of that, it wants to turn the handlebars into the wind, which helps keep you riding in a straight line.”

Knight Composites aero road bike wheels drag comparison chart

 

The end result for their 65mm depth wheels was about a 30g reduction in drag at 25-30mph across a wide range of crosswind angles from 0º all the way to 20º (tested front wheel only, corrected for atmosphere, etc.).

knight-composites-aero-carbon-wheels-lineup

The line kicks off with three different rim depths: 35, 65 and 95 millimeters. Specs are:

knight-composites-aero-carbon-wheel-specs

Retail is $2,599 per set for the 35 and 65, and $2,899 for the 95mm, all with DT Swiss 240 hubs. They can also be built with DT 180 hubs, and they’re building the wheels with Aivee hubs for Horner’s team.

While Lucas’ former employer ENVE prides itself on making their carbon wheels domestically, she says they went to Taiwan because they found it to be a competitive advantage since they’re doing things a bit differently.

“There are some people out there that assume we’re going to Taiwan because it’s cheap,” she said, “but the factory we’re using, it’s not cheap at all. We wanted to make our wheels as strong and light as possible by using the same technologies at the same places that make the top Pro Tour level frames. We can honestly say we’re a third generation wheel company, using the best and latest technology and techniques to make wheels better and differently than anyone else.”

Quan expanded on that, adding “We use the same double tooling method that has an EPS foam mandrel on the inside and a metal mold on the outside. The same process as high end carbon bike frames.”

Knight Composites 65mm deep aero road bike wheels

That higher compaction lets them use less material, which results in a rim that they say is about 20-30g lighter than the competition. Because there is less carbon needed on the walls, Quan puts a little extra material on the brake track to thicken them up to help better dissipate heat. He says their brake track is up to twice as thick as the competition at 3+ millimeters thick.

At the moment, they do not recommend running them tubeless. Quan says they’re talking with a major tire manufacturer, but the issue remains compatibility and the lack of a road tubeless standard. They have gone through the development process for tubeless mountain bike wheels, though…

WHAT’S NEXT?

“We’re starting with wheels and we’re sticking to what we know,” says Lucas. “We have clinchers now, and in late spring we’ll introduce tubulars. Around Sea Otter we should have our mountain bike wheels, and then eventually our disc brake wheels for cyclocross in time for the start of next season.

“Will we go into components in the future? Probably, but at the end of the day we didn’t want to make (a part) just to make a buck. I told Jim when we started, if it’s not going to be ours and be proprietary, I’m not interested. And that’s what we’ve done with the mountain bike wheels and the tubulars.”

KnightComposites.com

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Dinger
Dinger
7 years ago

Same observations and exectution that led to Zipp’s Firecrest and Bontrager’s D3 shapes, no?

Veganpotter
Veganpotter
7 years ago

Zipps are more blunt.

anonymous
anonymous
7 years ago

One would think if aero were #1, they’d try to reduce spoke count.

Eric
Eric
7 years ago

All this “new cutting edge technology” was created way back in 1988 when the late Steve Hed created the first Hed CX wheel. (Article in the January 2015 Cyclist magazine – British publication) It’s almost the same shape and width of every other wheel on the market right now and would still be just as fast as most of them too.
Everything else is just a copy of a copy which are all so close in performance anyway. At the end of the day it comes down to the best marketing plan to get the folks who have the money to buy the speed.

Zeb
Zeb
7 years ago

This sounds like everything zipp published as cutting edge when firecrest came out a few years ago. And they’re very similar in shape to HED rims which have been in production for even longer. I think even the most uninformed of bicycle consumers these days knows that wide u-shaped rims are “more aero” and “better in cross winds.” Nothing about this is cutting edge really, but it seems like a much more convincing marketing scheme than open mold china carbon rims / hubs that are “assembled in america” and have special stickers on them.

Many new wheel manufacturers are appearing these days and they’re all either budget open mold companies, or custom rim shapes and layups for more money. Nobody has effectively met the market demand for an affordable race wheetset that falls in the middle ground between cheap copies and custom boutique. This is by far the best attempt I’ve seen so far, but 2500 retail is still TOO much for me to want to buy these over normal china carbon rims. And if i have 2500 to spend, I’m gonna find ENVE, ZIPP or HED for 2500 (its not that difficult)

Kramer
7 years ago

Zipp has been speaking about and looking at the trailing edge for over 5 years, that’s what Firecrest is, nothing new ! I think that if you look at the CFD that is being used here is is far less sophisticated to what Zipp is using. The comment about building in Taiwan is because they don’t have the ability to make the rims themselvesoyherwise they would.

Alex @ Hermes Sport
7 years ago

@Zeb yeah, there’s been something of a hollowing out of the market in the middle, as most people either race to the bottom or the top, depending on what they’re trying to do.

Alex
Alex
7 years ago

Nice, but not that impressed. Check out Rolf Prima carbon wheels. Made in Oregon. More aero, lighter, and at a reasonable price. White Industries hubs. Hard to beat.

John
John
7 years ago

The aerodynamic evaluation of any object in subsonic flow must never overlook the leading edge, which is usually more important than the trailing edge flow. This is because the air flow moving over the front part of the body should be laminar as long as possible before either laminar separation occurs or transition to turbulence occurs. This is done to reduce aerodynamic drag because flow separation invariably results in a low aft body pressure resulting in higher drag. If the flow were strictly turbulent, which is much better than having flow separation, the drag due to skin friction would be higher than if the flow were strictly laminar. In reality, at best laminar flow occurs only over a very short distance back from the leading edge of a blunt body such as a wheel/tire combo.

However with a wheel you have three aero zones that need addressing: 1. The front of the wheel leading edge (tire); 2: The rear of the wheel leading edge (rim profile); 3: The top and bottom parts of the wheel (complex leading edge). Each of these zones has their own aerodynamic characteristics that need to be optimized for a range of wind incidence angles. In addition, the wheel’s aerodynamics will depend strongly on the frame and fork design since the air flow will be affected to a large degree on how the proximity of the frame tubes and their individual shapes and how these shapes interact with a spinning wheel. This is a complex problem and simply using computation fluid dynamics and limited wind tunnel testing will not generally result in an optimized wheel. This is why we continue to see more developments in the wheel designs as the engineers try new designs and test them over and over. Eventually, after a number of new designs have been tested, we see that maybe a small gain was realized with one of the new shapes with or without textures (such as dimpling). It really is more trial and error than anything.

cerebis
cerebis
7 years ago

– Website outlines aero data stating all were done at 25mph, but the figure says 30mph.
– Subtracting strut drag could explain the negative drag as being only an artefact.
– Why not explicit state what the other wheels are or at least the depths?
– Front wheel only, not in a frame — the point being the next bullet.
– 65mm is a lot deeper than 58mm (Zipp) and deeper than 60mm (Enve front, which was optimised for drag with bike).

I guess we’ll have to wait for a shoot-out from the German Velo magazine.

ginsu
ginsu
7 years ago

I really like these analyses, but I do *hope* that a rotating wheel is being simulated in the CFD, otherwise it’s all pretty moot.

Gesp5151
6 years ago

I think they are great wheels: not got a lot to compare them to but I stuck 5.5% increase on my hour record on the same route so pretty impressed. It was also windy but they seemed to manage the crosswinds pretty well also.

Tom haedrich
6 years ago

Would suggest looking at superiorlite wheels. Quietly building top level hoops for some impressive clientele since 2008. Each wheel hand built in south carolina and hits all the same top level wheel engineering criteria without all the bs and at 1/2 the price direct to consumer. Not big but definately great hand made wheels.