Admit it, we all love a good-looking, great-sounding pair of wheels on our time trial bikes. Likely you first caught the bug as a newbie at a TT race or a triathlon, probably being passed by some faster competitor with a distinctive “whomp whomp” sound emanating from their rear disk.
These days, solid rear discs and deep-section front wheels are everywhere. And while it might be tempting to fixate on the disc at the back, most aero nerds will agree that it’s the front wheel that stands to make a greater difference to your aerodynamics and speed.
So I decided to do a mini test ahead of my last 10-mile TT of the year, to determine which of the wheels I have in my bike shed to run on my first outing on the fast (on paper) P612 course in Hampshire this weekend.
For this test, I chose three out of the four TT front wheels I own, deciding not to test the older Enve 8.9 tubular wheel, since it’s been out a production quite a while now (still a great wheel if you can find a secondhand one in good condition! Here's a comparison of the 7.8 vs 8.9 I did a while back). The three are all rim brakes and being used with my Giant Trinity frame:
Enve 7.8 – a 78mm deep, 29mm wide spoked front wheel with DT Swiss hub (built by Strada Handbuilt Wheels), fitted with a Michelin Power Time Trial 23mm clincher tyre (with a latex tube). Tyre at approx. 90psi.
Strada Power Trispoke – a three-bladed wheel with a circa 78mm deep outer rim, fitted with a 25mm Continental GP5000 TT tubeless (with sealant) tyre. Trye at approx. 90psi.
Aerocoach Aeox Titan – 100mm deep spoked front wheel, fitted with a Vittoria Corsa Speed 23mm tubeless (with sealant) tyre. Tyre at approx. 90psi.
On the rear was Strada’s TT disc, fitted with a Continental GP5000 TT tubeless in 25mm.
The elephant in the room - the tyres and pressures
Yes okay, let’s get one of the testing flaws out of the way: the tyres are all different. Because I bought the wheels at different times (they’re all mine, bought and paid for, no freebies here) and the tyres are those recommended by the suppliers at time of purchase.
But to clear up the arguments around rolling resistance variables, I think it’s pretty negligible. On Bicyclerollingresistence.com it states the rolling resistance in Watts for each tyre as follows:
Michelin Power Time Trial: 9.2 Watts (for what it’s worth, I think the tyre is faster than this figure suggests)
Continental GP5000 TT: 7.6 Watts
Vittoria Corsa Speed: 7.5 Watts
So it’s all VERY close.
The testing protocol
Testing was performed on public roads, back to back with minimal time to swap wheels. Each ride was split into three sectors, with a little recovery time between each sector.
Sector 1 – a 3.8km section of “ok” road surface heading South West, road fairly open to wind, ridden at approximately 235 watts*.
Sector 2 – a 1.85km section of “good” road surface heading South, road sheltered from wind for the most part; ridden at approximately 260 watts.
Sector 3a and 3b – the reverse of sectors 1 and 2, ridden as one sector: 1.85km North on a good sheltered road, then 3.8km heading North East on the open road. Ridden at approximately 235 watts.
The wind, according to the Met Office, was 17.7kph out of the South West (making Sector 1 a headwind and Sector 3b a tailwind)
* I would normally race a 10-mile TT at significantly higher watts, but I didn’t want to risk fatigue causing a bigger variation in power output between the first and last runs.
The anecdotal evidence – feel
The first set of runs was done on the Aerocoach Aeox Titan. I ran this wheel for the first time at a recent race on P881/25 and, despite the gusty winds, was pleasantly surprised that it wasn’t more of a handful. It’s by no means immune to the wind, but not as bad as a 100mm deep front wheel perhaps should be (or would have been a few years ago).
Into the headwind on sector 1, it felt okay certainly within acceptable limits for the B-road nature of the course. Sector 2 was a breeze (thanks to the lack of it!) and sector 3 was frankly unremarkable. You get a sense that, once up to speed, the Titan holds it pretty well. It’s a pretty stiff wheel, as you’d expect for the rim depth, a little crashy on bad surfaces. The aero fairings on the hubs are a neat feature (UCI legal round ones also come with the wheel) the valve being hidden inside the rim is also clever (although a complete fiddle to get installed and you need the right pump head inflate it).
The moment I hit the start point for sector 1 (I tried my best to start each sector at about the same speed on each run) my immediate response was “feels slower”. Knowing well that things can feel slow when they’re fast (and vice versa) I just concentrated on maintaining the same average power as I had set on the first run with the Titan. Being a shallower rim, there was less effect from the head and cross winds. I’ve had this wheel for more than a year now and set some pretty significant PBs on it, so I know it’s not slow. Let’s also not forget that, on paper, the Enve’s Michelin tyre has the highest rolling resistance.
The last run was on the Trispoke. I desperately wanted this to be the fastest – if only because it undoubtedly looks the best! Coming out of the village to start sector 1 I got hit by a crosswind that took the front wheel from me more than I had experienced on either the Titan or the Enve.
Of course, it could have just been an especially strong gust. But it happened again a couple of times on the sector 1 run. This confirmed my suspicions from recent TT races that this wheel is somehow very susceptible to the wind. Sector 2 and 3 were less eventful and I was able to settle in and ride to the target average power.
I’ll share the raw results first, then do my best to provide a little bit of analysis.
I’ve listed the distance recorded (I was manually using the lap function on my Garmin), the time, power and speed for each wheel on each sector.
So, you can probably see by now that there was a clear winner overall. Combined across the three sectors (total of about 11.25km), the Titan was approximately nine seconds quicker than the Enve and about 12.5 seconds faster than the Trispoke.
But it’s worth looking at each sector.
Into the headwind on sector 1, the Titan was a full five seconds clear of the Enve and seven seconds faster than the Trispoke.
However, move onto the sheltered road of sector 2 and it’s a lot closer, especially between the Titan and the Trispoke, with just 0.4 seconds (remember there’s room for manual error here as I was recording the distance on the Garmin) between them, which could easily be accounted for by the very slightly lower power on the Trispoke run. I am a little surprised the Enve didn’t test faster here, especially looking at the power.
Sector 3 is perhaps the most representative of a race, albeit a very short one, thanks to the multi-directional nature (about 1.7km North and then 3.8km North West – mostly a tailwind).
Again, while the results come out in favour of the Titan, it’s very close to the Enve.
My reading of this is that with a tailwind, the Titan and Enve are very close (this is kinda contradicted by the sector 2 results, I admit). But into a headwind the Titan is the surprising winner.
What we can see is that into the headwind the Titan averaged 41.2kph for 234 Watts (I’m racing this weekend, there were no heroics on the power front), while with a tailwind, the speed increased by only 0.7kph.
In contrast, the Enve went from 40.8kph into the headwind to 42kph with the tailwind, a much more impressive 1.2kph increase.
The flaws in the testing
Yes, there were flaws in the test. Using public roads and a test lasting over an hour in total duration was not ideal. Having different tyres was not ideal. Dealing with the effects of passing traffic was not ideal. Having variances of up to seven watts (2.65%) on runs was not ideal.
I also want to acknowledge that aerodynamics change at different speeds, so I know that testing at 40-44kph is not the same as testing at 50kph. But frankly I’m not strong enough to do a full hour of testing at 50kph and still be in a fit state to race a couple of days later! So there…
So I’m fine if you choose to take the results with a pinch (or handful) of salt.
Having griped about poor performances when using the Trispoke previously, this test does seem to confirm that it just isn’t fast for me, at least not when there’s any wind about. On the sheltered sector 2, it felt great, on sector 1 it just felt a handful. It’s a real shame as I love how this wheel looks.
Maybe it’s faster on other bikes. Maybe it needs a different tyre or different pressures. I’d like to try other trispokes, or maybe something like Cadex’s quad-spoke, to see if they work better on the Trinity frame. You hear so much positivity about trispokes (having spoken to Darren at Strada I know his other athletes are getting on really well with it!) that it’s difficult to reconcile my own findings with what others report.
The Enve 7.8 confirms itself as an excellent all-rounder. Not too affected by winds and within a second of the lead on the 5.8km sector 3. Clearly no surprise how I’ve managed to set multiple PBs on this wheel, built for me by the masters at Strada.
The Titan was the unknown. A lot of people dismiss it as 'old tech' and perhaps not too many folks would run a 100mm deep front wheel in gusty conditions, but today it was fine (ask me another time if I’d run it in 25kph crosswinds). I didn’t weigh the wheels before testing (maybe I’ll this info later), but it’s clearly not a wheel to go climbing mountains on. But for flat fast course, it’s pretty quick.
A huge change in the weather forecast aside, I think I know what I’ll be running on Sunday (and which one I'll be taking as my spare).
If any wheel manufacturers out there think they have a faster wheel, please do feel free to get in contact, I’m very open to more (flawed) tests like this.
For a more scientific wind tunnel-based test, I recommend this blog from Max at SSE Hub: https://silverstonesportshub.co.uk/2023/10/12/frontwheeltesting/. Although the wheels are not named in the blog, I have some insider knowledge and it turns out the wind tunnel wasn't so different to my own testing...