Delusions of Aero: My Attempts at Budget Marginal Gains on the Bike

As part of a delusional attempt to buy myself faster on the bike, I made changes to my Canyon Ultimate CF SLX over the winter months. It took me almost a year, however to finally get my second tire in and have a chance to try everything out.

  1. Light Bicycle AR465 Falcon Pro X-Flow 46.5mm Depth Wheelset – $1237.14
  2. 2 x Continental GP5000S TR tires (25mm front, 30mm rear) – ~$200 from Amazon and BikeTiresDirect
  3. Aero water bottles – $20.60 from Amazon
  4. Shimano 105 Fc-R7000 Crankset – 160mm – $159.99 from Jenson USA

Let me start by saying that all these attempted gains are marginal, extremely marginal. 100G of weight savings is just .22 pounds, and yet I can’t help myself. Imagine trying to lose that weight off your body instead of buying it. People with this insanity are Weight Weenies, as popularized by the forum.

There are two types of changes, weight and aero. Reduced weight helps you ascend faster, particularly as you go above 6% gradients – the higher the gradient, the more reduced weight helps. Aero helps you with anything less than 6%.

The reality is I am unlikely to hold enough power for enough time to measure the difference any of these changes will make. I know this and I don’t need to brag to others about this gear, but I just like knowing for myself. I want to know I have a lighter rim, a more aero tire. But I want to know that I “achieved” all this at bargain prices too.

Wheels and Tires

Below is the configuration I opted for with the Light Bicycle AR465 Falcon Pro X-Flow 46.5mm Depth Wheelset.

  • Internal Nipples (more aero, but harder to service)
  • Flyweight (lighter version of the rim, but less strong – more of an issue for 200lbs+ riders)
  • Pillar Wing aero spokes

The X-Flow rim shape itself is supposed to be Light Bicycle’s new innovation, their faster, stronger, stiffer design. It looks like a very subtle version of the Zipp and Princeton Carbonworks wheels. The 46.5MM depth is their deepest in this rim shape, but I am also concerned about crosswinds and so this seemed like a good balance of aero gain, crosswind vulnerability, and light weight, especially with the decisions around the nipples, spokes and tires.

Or so I tell myself.

The wheelset came in at 1,364G (+30G for tubeless tape). If you’re new to weight weenyism, 1500G is a good solid non-heavy wheelset, like a B- grade. 1400G is the B, 1300G is the A-, and 1200G is an A. I think there are wheelsets that might break 1100 G. The difference in 150G (.33 lbs) in weight between wheelsets can often be $500 and greater.

I got the Bitex Hubs because they were lighter, cheaper, and came in the oil slick color. It was the only hub that could be paired with the Pillar Wing aero spokes that also came in the oil slick color.

On the tires, I’ve already run Continental’s original excellent GP5000 tubeless tires on my Roval CL32 32MM depth wheelset before. But but but! I needed to maintain aero efficiency through the so-called 105% rule (you want the tire to be thinner than the rim by at least 5% in order to create a smooth airflow interface between tire and rim). But but but! The new GP5000S tires were lighter than the originals due to removing a layer of rubber originally intended to remove the need for sealant. But but but!

So now, instead of two 28MM GP5000s on 32MM depth wheels, I’ll be on 25MM GP5000S TR on the front, 30MM GP5000S TR on the back (wider tires on the back wheel are of much lesser concern because they receive the disrupted airflow from your body) with these deeper 46.5MM depth wheels. The Light Bicycle wheels are 28MM to 30MM in width.

Actual tire measurements when inflated to 80PSI (front) and 65PSI (rear) were 26.6MM for the 25MM tires and 31.1 for the 30MM tires, perfectly hitting 105% in the front.

The weight difference seems to be about 50G per tire, 100g total not accounting for the front tire difference (Going from 28MM down to to 25MM). My Roval wheelset is probably 1450-1500G. In total, maybe this is a savings of 200G.

Lighter and more aero!

If you haven’t noticed yet, there’s actually something really cool about the wheelset. It was a special gift from my wife, and this kickstarted the entire exercise of “what else should I consider changing?” The wheels are customized with a cycling graphic decal around the rim and with the names of my two sons. (The customization was about $180, everything was $1,237.14) Matching the aero spokes, the name and Light Bicycle logo stickers on the rim, and Bitex hubs are these Muc-Off Tubeless Presta Valves.

Water Bottles

Water bottles are this bulging thing that disrupt airflow as it flows around your bicycle frame. Initially, I purchased the Elite Fly 950ml (33.4 oz) bottle with the idea of using a single bottle (and bottle cage) on the seat tube, removing the downtube bottle cage. The bottle is extremely light (thin). The rationale was using a single larger water bottle on the seat tube would create less aero disruption than two bottles on the down and seat tubes because a lot of the air that gets there has already been disrupted by your spinning legs. I like to carry a lot of water (just in case) so I needed the biggest bottle I could find.

I then saw these aero bottles based on an Elite design which is no longer being produced. Instead of bulging out of your frame, they’re basically inline with it, theoretically causing less turbulence. Together, they carry about 1000ml (35 oz) of liquid. I originally saw the bottles on Aliexpress but when I saw them sold on Amazon, I decided I didn’t want to wait a month for them to arrive from China.

There are two versions of these bottles. One uses a form fitting bottle cage. The other has magnets within a rail that holds the bottle. I got the latter as I saw some random comments that the cage didn’t hold the bottle tightly. I also liked the idea of magnets, though I did wonder about the weight difference….Overall, I decided that aero was going to be more important than weight.


This one was more straight-forward. I am shorter than most people at 167CM tall (5’6). I have long legs for my size (30″ inseam) but I still don’t have “long” legs. The length of a crank determines how high and low your legs go when pedaling. A longer crank means your knees get closer to your body as you pedal up – this can cause breathing discomfort as well as knee pain. Some people like longer cranks because they produce better leverage.

I just wanted shorter cranks in order to optimize my pedaling and make it easier to breath when hunched over in aero positions. I got a new bike fit right after the switch.

Previously, I had Ultegra R8000 170MM cranks. I have now switched to Shimano 105 FC-R7000 in 160MM. But isn’t 105 heavier than Ultegra you ask? Yes, the difference in these cranksets is a whopping 39.4g / .09 lbs! So not even worth thinking about. In addition, Ultegra cranksets don’t go as short as 160MM and retail for over 180% the cost of the 105’s. The 105 crankset blends in well the with rest of the Ultegra groupset too.

Much Ado About…

Me, on the right. I posed.

It took me almost a year to actually ride all these changes and I didn’t hold back through some test ride. I did Foxy’s Fall Century in Davis, CA, 100 miles and an easy day of 3100 ft of climbing.

I enjoyed the ride, but can I really tell the difference? No. Then again, it had been a year since I rode outdoors. I suppose this is what hobby is all about. Nothing but what’s in your mind.