Testing bikes and equipment with power and HR to find out what is faster

Thought I would start a thread with data and see where it goes. I have a 14-15 minute test loop and have been looking at things like clothing, tires, and today, bikes…as in how much slower is the trail bike vs. the marathon XC bike?

OK so first we have to figure out these power meters. I made a zwift workout for a constant 160 watts, locked out the shocks, and swapped bikes back and forth on a wheel off trainer. ABABAB, the trail bike (YT Izzo with quark) read 168, 169, and 167 watts, the XC marathon bike (Canyon Lux Trail with power2max) read 158, 156, 157. So I went with “Izzo @ 168 delivers 160 watts to the wheel” and “Lux @ 157 delivers 160 watts to the wheel”

Then off to the test loop, 14 1/2 minutes of twists and turns. No climbing though, it’s super flat. I have around 150 laps on this particular segment so it’s familiar. Swap bikes ABABABAB so 4 laps per bike alternating with the Izzo at 168 watt ave power and the Lux at 157 watt ave power.

Gotta say, I’m a bit surprised they are the same. The Lux feels very fast and the Izzo is just a big, soft, squishy thing. I’m questioning the need for the Lux, despite it’s sprightly feel. The Izzo requires less thinking…just kinda monster truck over the little stuff. Feels really slow though!

I’ve felt this before with tires…comparing sketchy XC race tires vs. knobby meats. The big tires feel like they corner on rails but then you look at the lap times and you find you are going so much slower. Specialized Butcher 29X2.6 vs. Kenda Booster Pro 29X2.6, swapping only the front wheel, nets almost 30 seconds on my test lap. So yeah, you feel like you have tons of control with the Butcher but part of it is that you are going way slower.

Anyway, just throwing some data out there, curious to hear what other people are doing to optimize their setups.



Interesting results, very repeatable methodology!

Just curious, what do you think the results would be if you just went all out on each bike? Do you think they would set equal times at full race pace? Or is there something about the way each bike handles it something that might give it an edge at speeds higher than what you just tested at?

My take on this is like….your old Buick and new corvette go the same speed down the interstate, it’s not until you push them do you see the obvious difference. Or maybe my skills are such that I can’t extract the speed out of the higher performing bike. Which I really hope is not the case!

But maybe running at a faster pace would bring out a difference. The problem is that 14 minutes is about as fast as I can go and be consistent and repeatable. Faster than that and stuff happens….or it doesn’t and I end up with a heater.

Also, I am convinced some bikes just feel better to pedal and you may be able to get more out of yourself on those bikes vs bikes that “just feel slow”, even if they run the same speed on the same power.

But back to your point.,…I don’t know but I think maybe. The trail bike is easier and more forgiving so maybe as speed increases that would be faster but it could easily be the other way.


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Yeah, if I were in your shoes I wouldn’t know either. I was really curious to see if you had any thoughts…

The bikes aren’t that different :thinking:

I don’t know where you’re based but around here (Southern UK) I’d consider an XC bike to be a 100-120mm 29er and a “trail” bike more like a 140+29er or 160+ 27.5.

And then consider the differences. an XC bike will pedal up a bit quicker but will descend slower :thinking: On a “flat” course the XC bike will win in most cases using my example but yours are two very similar bikes.

I’m always of the opinion that in most cases its not the bike its the rider. Example, we have a trail here which is pretty flat, some twisty burms, a small gap and a small drop. I can do it around 57 seconds on my MTB. I rode 3 other bikes, 2 were way too big for me, one was similar but I still got 57 seconds on all of them :smile:

That’s another possibility for sure…that the bikes are just not different enough to matter. Definitely a good idea. But I tell you what…they sure feel different! And lining up with the trial bike at XC races is like…I’m self conscious LOL.


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Have some data comparing the Kenda Booster Pro TR 2.6 vs. the Schwalbe Thunder Burt Super Ground Addix Speed 2.25 on the rear wheel…front wheel stayed the same (booster pro 2.6). The data says they are well within the limits of my test…which is probably right. I’d guess the super ground casing is a little tougher than the TR casing…that light Kenda casing feels road tire thin…if that. I have ridden it awhile here in Florida without any problems and it came thru 5 endurance races of ~ 2 1/2 hours each this spring. Between laps 4 and 5 I took a lap with a friends wheelset…2.25" race king protection front and rear on bontrager kovee pro (1400g) wheels and smoked a 13:45 lap at the same 165 watts. I think swapping both tires vs. one tire would make it easier to see a difference so that might be something I try in the future, maybe booster pro vs. race kings and swap both wheels every lap. The race kings are definitely smaller and I had at least 1/2 dozen pedal strikes on that lap.Anyway…here is the data :slight_smile:

I have picked up a trail bike this year to complement the XC bike. I have to say, the weight difference is noticeable, and the squishiness and length take extra thought, but I agree that the biggest difference is the tyres. Going to Assegai and DHR from the 2.4" XC tyres appears to add ~30W and is just at rolling around speeds (up to ~24km/h).

The funny thing is, my XC bike is still faster everywhere, up and down, but the big bike can take me a lot more places, and is easier to clear chunky sections.

I’d bet at least 30 watts. When I ran the Specialized Butchers vs. the Kenda Booster Pros it was 30 seconds per lap slower…only swapping the front wheel! The Butchers felt so secure, just corner on rails brah!..but then you look at the times and it’s mostly because you are going so incredibly slowly.

You got data on that? Because when I ran the canyon lux vs. the yt izzo, the lux felt literally twice as fast…but the data said they ran the same. I took a lap on my buddy’s Fezzari Signal Peak when I ran the kendas vs. the schwalbes and it felt blisteringly fast as well but clocked in at 13:55. (Different power meter so I can’t know for sure though)


Only Strava segments.

I have now got a few climbs that are a couple minutes slower for more Watts, and descents that are about the same or a tiny bit slower.

I haven’t controlled for tyres or weight, but it’s been pretty surprising as I was sure the Kona would destroy the XC bike on the downs.

The Kona climbs well, but is a slug in tight stuff or if you need to regain speed. The XC bike is much more feedback and a lot closer to the edge, but requires far less effort to maintain speed on.

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