Video: Racing the XC Olympic Champion, Jolanda Neff vs. Tom Bradshaw

 @SATN-XC thanks mate! It turns out acoustic e-bike racing is perfect training for XC sufferfesting...

 100% agree with the second statement, but I don't think Tom was on an e-bike.

 Word, I’d just be interested to know how much difference the bike makes.

 I think we should send him out over and over to be flogged by Jolanda in the name of science.

 If you're really interested in seeing the difference between different types of top-level talent, just look at the UCI Team Relay results at world championships from years prior. I seem to recall that the top women elite riders were near the same level as top-level men junior elite riders, but it's not easy to find splits from those anywhere but the official replays.

 Tom was on XC race tires, so that's the biggest difference taken care of. I'm sure a proper XC race bike would've helped a little, but probably less than most people would expect. Definitely of interest to test that.

In any case, the bike (excluding tires) surely accounts for many seconds per lap, but Jolanda was ahead by minutes - there's no bike without a motor that would've bridged half that gap!

 @R-M-R: An XC race bike has to be worth at least 10-15% maybe 20% time (I actually think it would impact a non-XC racer but generally fit rider like Tom more than a pro like Jolanda). Think about the climbing geometry, travel and pedaling efficiency of an XC bike vs enduro. Tires are the biggest factor but climbing geo/suspension efficiency (front and rear) followed by total bike weight would have a huge impact on fatigue and thus sustained power output.

 @gramboh: The difference is not trivial, but I feel 20% is too high. 10% ... maybe.

First, the easy one: weight. We need to look at total system weight, not bike weight. Let's first consider components. Imagine if we halved or doubled the weight of a single screw; we know that wouldn't make a significant difference because it's a drop in a bucket. Similarly, we could halve or double the weight of a stem and it's still not much. The same is true of the whole bike. I doubt the difference is ten pounds, but even if it is, that's about 5% of the total weight, which would translate to slightly more than 5% slower on climbs. Negligible difference on flat ground or descents, though.

Geometry: Not convinced this will make much difference. Modern, steep seat-tube angles have made the biomechanical efficiency of trail, AM, enduro, etc. bikes pretty good.

Mechanical efficiency: Difficult to say. Long-travel bikes are surprisingly efficient when seated, only losing ground dramatically to XC bikes when standing. The Commencal Meta has plenty of pedaling anti-squat and maybe Tom used a climb switch on the longest and smoothest climbs. I'm sure the XC bike is more efficient, I'm just saying the margin is less than it once was.

Descending: Likely a small advantage for Tom's bike.

Overall fatigue: Hopefully not a major issue on a single lap, so the time differences should(?) respond close to linearly with the differences in weight and efficiency.

Overall: Only way to be sure is to try it, and I'd watch the hell out of a well-executed test. Until then, I'm guesstimating 10% or less, given the use of XC race tires on Tom's bike. If Tom hadn't crashed and was on a particularly efficient XC race bike, maybe he would've been close to Jolanda's slowest lap. Compared to her fastest lap - not even considering one lap vs. a whole race - Tom has some work to do!

 @R-M-R: This must be an experiment that was done properly somewhere at some point eh?

The years I was racing XC (age group punter), my difference between climbing on the XC bike vs my usual heavy Enduro bike was consistently 1:30 for the same half hour climb. That's 5% for the up. But that's just anecdotal evidence from an amateur.
Though unlike Tom I was on different tires, weight difference between XC tires and Enduro tires was usually bit over 2lbs (950g) for the pair. Going by feel though, tires and wheels felt like 15lbs difference...

I'm guessing Tom would get beat on an XC bike too. What masochist would do that to themselves though? Keep the barrier up. It's like "Hey Tyson, let's put on the light 10oz boxing gloves and jump in the ring!"

 @DirkMcClerkin: Many experiments have been done, unfortunately with equally many variables!

The main difference with tires is not due to the weight - though that can be considerable - but the rolling efficiency and driving efficiency. Check out bicyclerollingresistance.com and you'll see many examples of heavier tires rolling faster than light tires. Their test equipment does not test driving efficiency, as their equipment does not apply shear force to the casing and lugs, so there will be additional losses from flexible, slow-rebounding lugs, though sometimes those lugs can gain back efficiency from greater traction. Tire efficiency is complicated!

The bike industry has only recently started to understand dynamic geometry, which is a large portion of what's driving the trend toward steeper seat-tube angles. For decades, we assumed the 73° seat-tube angle of road bikes was ideal, ignoring: 1. road climbs are rarely steeper than 5°, and 2. road bikes do not have suspension that pitches rearward on inclined ground. Dirt climbs are steeper and our suspension exacerbates the problem when it pitches several degrees rearward, hence the need for much steeper seat-tube angles, especially on long-travel chassis.

If your time difference was only 5%, only on climbs, and with different tires, your times would almost certainly be a lot closer with XC race tires on both bikes and over an entire lap.

 @R-M-R: The tires do make a difference. However, there are a lot more metrics than just the tires. The weight of the enduro bike is a big difference. Enduro bike 30lbs+ compared to XC bike 22-24lbs. Also, the geometry makes a difference in pedaling efficiency and body position for climbs. I used to have an enduro bike and XC bike at the same time. The XC bike was way, way faster climbing. It felt like it was almost cheating like with an ebike. Lol.

 @tacklingdummy: Sample size of two, me and you. Science settled!

Just to be clear, I totally agree with you. I also was trying to say the difference is pretty vast. Getting to the top of a climb a minute and a half ahead is an eternity.

Then again, your bike is only as fast as you. After quit racing and Twinkie season started I would drag that XC bike up there 5-7 minutes back from the fit days lol.

 @tacklingdummy: Yes, XC bikes are a lot faster than enduro bikes on XC courses and there certainly is more to it than tires, which I discussed above!

It's true that a difference of approximately ten pounds between bikes makes a difference. The weight is difficult to separate from everything else, though, when there can be so many variables. If an enduro bike has ten extra pounds plus chunky tires with stiff casings, loads of travel, slower steering that may result in handling errors at low speeds, etc., it's impossible to attribute the difference in speed solely to the difference in weight or to accurately apportion the time losses to the various parameters.

Some enduro bikes put the rider in a biomechanically efficient position and have extremely stable pedaling performance (at least when seated). Obviously, they would still be less efficient on a typical XC race course, most of which would be due to enduro tires vs. XC race tires, a good chunk due to weight, and a difficult to quantify amount due to geometry, handling, and suspension efficiency.

 @R-M-R: I would love to see Jolanda do 3 laps on her bike and 3 on an enduro bike to see the difference the bike makes. Heck even throw in a few laps on a down country bike while she’s at it. Come on @Tombrad make it happen. Awesome video by the way.

 @zmums:

Roughly speaking, each extra pound of bike or body weight costs you about 10 seconds for every 1000 feet of climbing, but that doesn’t speak to the difference in efficiencies of the bikes.

Also, if you put out a mere 10 watts more on that 1000 foot climb, it’s the same as being 6 pounds lighter. That is, increasing one’s power is much more effective than losing weight.

 @hllclmbr: wouldn't that vary depending on the steepness of the climb? I thought weight made more of a difference as pitch increased. But I barely passed physics, so not sure.

 @SangamonTaylor: Correct. It also varies with the total system weight. 1 lb makes less difference to a 210 lb system than to a 120 lb system, which is roughly the range of total weights at the pro road or XC level.

Same principle for how much those ten watts matter: it depends on the rider's output. 10 W to a low output rider is a big deal, but not as much for a big engine. The general idea is sound, it just needs to be less rigid to accommodate individual cases.


@Stumpy2: Yes, would love to see it! Or any rider who can put out a consistent effort across the entire test. It would be important to normalize as much as possible for many variables that are often overlooked, including dynamic geometry (ex. rider position on the most important climbs).

 @Stumpy2: She would be much slower in an enduro bike. The bike, bike weight, geo, rolling resistance, rotating mass, etc makes a big difference. It is funny how so many are downplaying the bike, but all things being equal and the only difference is the bike, you would see a big difference in times. If the bike didn't make that much of a difference, you would see world cup XC racers on heavy enduro bikes with slack geo and big knobbed tires instead of shaving grams off their bikes, upside down stems, XC tires, etc.

 @R-M-R: Looking at the RR data in your link for the MTB tires there's a correlation coefficient of .405 between watts and weight. If we just look at post 2015 data when they stopped using tubes in their test the correlation jumps to .571 which seems pretty good considering the multitude of other variables we know affects RR. It's certainly possible that a heavier tire rolls faster than some other lighter tire and it's true RR is more important than weight but generally speaking weight is probably the biggest single factor in predicting rolling resistance.

 I would happily bet (and I'm not a betting person) that if Yolanda was on a enduro bike and Tom was on an XC bike she would still easily beat him. Of course the margins would be smaller. Elite level racers in any field are a lot faster than most people realize.

 @jeremy3220: There certainly is a strong correlation, especially within a given brand, but there are also extreme outliers. Also, this does not indicate the weight is what's causing the resistance - especially since there is no change in elevation or acceleration during the BRR test. Rather, the weight can be indicative of things like the thickness of the butyl rubber, which is strongly correlated to rolling resistance, and lug volume, which may negatively affect rolling resistance and positively affect driving efficiency.

Broadly, I agree with you, but there are so many exceptions - and some of which deviate so dramatically from the trend - that I can't recommend trusting weight as an indicator of rolling resistance, let alone overall efficiency.

I've listed below some examples from BRR that do not follow the trend of weight and rolling resistance. There are many more, of course.

Fat tires: The lightest tire is dead last on rolling resistance.
Kenda Juggernaut Pro
• 853 g
• 51.7 W @ 8 psi
VeeRubber Vee 8
• 1385 g
• 38.3 W @ 8 psi

Mountain tires:
Maxxis Ikon eXCeption Silkworm
• 583 g
• 38.2 W @ 25 psi
Schwalbe Thunder Burt Super Ground Addix Speed
• 680 g
• 15.7 W @ 25 psi

Touring tires:
Schwalbe Kojak
• 351 g
• 24.8 W @ 60 psi
Schwalbe Marathon Almotion (OneStar)
• 629 g
• 17.1 W @ 60 psi

 @R-M-R: In your MTB tire example you're comparing a 2014 tire + tube with a 2021 tire.

Saying the weight(mass) doesn't cause the resistance opens up a semantics wormhole but weight matters to a significant degree when it comes to rolling resistance. Adding more mass to a tire will increase rolling resistance, that doesn't mean a company can't screw up and make a crappy slow light tire though.

I feel that telling people weight doesn't matter, it's the rolling resistance that matters is technically mostly true but also misleading. Most people don't have access to the RR data of their tires or the tires they're considering. Without some other data weight is still the best predictor of how fast a tire will roll we have. Now if someone publishes data or a certain tire has a reputation as fast or slow rolling that's great. I don't think it's useful for people to ignore tire weight.

 @jeremy3220: Good catch on the tube issue for the mountain tires; I overlooked that. The other examples still stand. We can find similar examples within the mountain data that use the same air retention system, so the point stands. For example, the Michelin Force XC is slightly lighter than the Schwalbe Thunder Burt and has nearly double the rolling resistance in BRR's testing.

This is why I disagree with the statement that "adding more mass to a tire will increase rolling resistance". It is often true, but there are too many exceptions to make such a global statement. Even within a given brand, heavier tires can roll faster, so there's clearly more to rolling resistance - let alone overall tire efficiency - than mass.

No one is claiming weight should be ignored - whether tire weight or total system weight. I'm just saying it's a lesser factor in overall efficiency than many people realize and an unreliable predictor of tire efficiency.

 @R-M-R: I mean if you take a tire and add mass to it through thicker body plies or higher denier cord the RR will almost certainly increase. That doesn't mean a mfg can't produce one tire that rolls faster than a different model of the same brand. Yes, there's more to it than mass. It's somewhat unreliable as a predictor of tire efficiency but it's generally the only data consumers have. You can kinda get an idea of how fast a particular compound rolls but only as part of the overall package so when you compare say Maxxis' Maxx Terra compound to Specialized T7 you're also comparing different carcasses, tread patterns, etc.

 @tacklingdummy: I definitely understand and knew that before o commented but still would like to see the real world differences. It’s great the information people have provided but sometimes we just wanna see it with our own eyes.

 @jeremy3220: It's a frustrating situation, and yes, I've often used mass as a guesstimation tool in the absence of any other data. And I've often been wrong. I share the desire for something to predict tire efficiency, but that doesn't change the unreliable nature of weight as a predictor.

Even if we normalize for everything else, weight still isn't great. For example, we can look at road tires from Schwalbe, all of a consistent width, using the same casing, using the same puncture protection, using the same compound, and the Kojak is still slow. It's their slickest tire, so it's not even due to having a chunky tread. There are other examples, but that one stands out in my mind because I bought a pair of Kojaks for my commuter bike on the assumption they would be light and fast, only to find their dismal performance in BRR's testing!

The best predictor is to look at similar tires from a given brand. We may not have data for a given model, but we can probably dig up data on models from the same brand with the same casing and the same tread compound. We can broadly observe that top XC race tires from Schwalbe and Continental tend to have low rolling resistance, while Michelin and Maxxis appear to lag. As you noted, we might speculate a Maxxis MaxxSpeed will roll faster than a MaxxTerra, if all else is equal, which is precisely the point I'm getting at: the relationships are so inconsistent that it's best to compare single variables within a given brand - and even then it's occasionally inconsistent, but less so than between brands. Comparing weight across brands and using that as a predictor of efficiency is just too unreliable.

Things get even more difficult with enduro tires, which feature a more diverse range of casing constructions and compounds. We might speculate a construction with more material in the sidewalls and less under the tread (ex. Schwalbe Super Gravity) could have less rolling resistance than tires with less on the sidewalls and more under the tread (ex. Maxxis DoubleDown), despite the former being heavier, but that's just a guess until we have test data.

As I said, it's frustrating and I wish there was a reliable way for consumers to predict tire properties, but the relationships between specs like weight and compound with performance (rolling resistance, driving efficiency, traction, etc.) are all over the map.

 @R-M-R:
I can speak from personal experience.

My 2 bikes are a Transition Smuggler and a Merida 96 and I can tell you without a shadow of a doubt the XC bike WAY faster than the Smuggler at anything other than downhill.

The Smuggler feels like a fking pig compared to the XC bike. I often ride the bikes on the same trails and it is emphatic.

Tyres, absolutely. Everyone knows that.

But the geo and suspension as well. There is so much more bob and waddle to the Smuggler. The steep seat angle certainly helps the Smuggler, bit you simply cannot control the front end as well on climbs, or really get on top of the bike and hammer the power when you really need to.

The pedalling efficiency of an XC bike wicked in comparison, effortless. It is agile and sharp, you can rip it through corners and pick lines at will.

The XC bike destroys the Smuggler and it is a short travel down country bike. There is no way a full fledged enduro bike is going to keep up.

Downhill is a different story obviously, and the more technical the more different. The plush suspension and big, fat, soft tyres provide endless grip and stability, and you can rail as hard as your legs can take it.

The xc bike is surprisingly quick on a flow trail and its ability to carry momentum (it is far more efficient at pumping and holding speed) is seriously impressive. But the tyres and suspension simply don't offer the same grip or stability when slamming into berms or riding gnar.

 @Ktron: Thank you for sharing your experience!

That sounds about right, though I'm not sure I'd call a Smuggler a "fking pig", given how slow and squishy some bikes are - and even worse, how some bikes used to be!

There's a rotating stable of bikes in my garage and a proper XC rig is definitely faster on XC-appropriate terrain. Interestingly, though, the XC bikes feel faster by a greater margin than they are faster. The margin is real - don't get me wrong - but the quick handling and more direct connection to the ground intensify the sensation.

I've done my own back-to-back testing - not scientifically rigorous, just a stopwatch and a bunch of bikes, on multiple occasions - and "calmer" bikes were always deceiving. In particular, 26" XC bikes vs. anything with plus-sized tires dramatically distorted my ability to estimate the times. A memorable test occurred on a trail with a long section of embedded, sharp rocks, where a 130&140 mm Trail bike with 2.8" Rocket Ron Liteskin Pacestar tires was the fastest in a group that spanned from a 100 mm XC race bike to a 140&150 mm Trail/AM model. The rough section of trail was rougher than a typical XC race course, but overall, the trail was pretty XC and everyone assumed the XC race bike would be fastest, but those 2.8" tires with XC race construction made up more time in the rough than they lost elsewhere - and felt great in the process!

Similarly, if you've followed Pinkbike's group tests for the past few years, there have been instances where the most "racy" bikes weren't the fastest in the timed trail tests. The relationships between feel and course time were closer on the dirt road climb tests, though, suggesting our perceptions of efficiency can be accurate in some situations. Of course I'm not saying these tests prove all bikes that feel fast are actually slow, or anything of the sort, only that sensations can be deceiving and stopwatches exist for a reason!

Also, "fast" and "fun" aren't always the same thing. I have a XC bike that's currently set up very XC because it feels more fun and rewarding on less-technical trails. It's possible it could be slightly faster with some changes, but wouldn't have the pure XC feel I was looking for.

 @zmums: or not crashing and having ridden the course before

 Get ready for a stark contrast between the graciousness of an Olympic champion and the middle aged dads in your local weeknight series lol.

 @SangamonTaylor: LOL! Comment of the week!

 Yolanda came out to our local enduro race at Kanuga and humbled sooooooo many guys. And this was later on the same day she dominated the local CX race. So cool to get a glimpse of what it really means to be world class. Legend and always going to be a fan favorite.

 Yes, Tom is giving away a lot in the horsepower / weight ratio.
Jolanda is extremely fit and doesn't look like she weighs much. Tom is 10kg heavier than he was when he was fit.
We would need the % of climbing vs descending distances, I'm sure there's more climbing time than descending time.

 @Yaan: yes of course there is more time spent climbing. When i ride it's usually around 80% climbing. How else would they be able to go around a closed loop?

 @Muckal: Thank you for proving my point. That is where Tom lost most of his time.

 @Yaan: while @Tombrad is 10kg heavier than when he was XCO race specific fit.... I'd hazard a guess that given the intervening years (and what he's done with them), he is significantly stronger and more powerful than he was back then. And likely also has a much larger aerobic base too

 Super impressed. He's an animal. Panda maybe. But a ferocious one that raced World Cup XC. .

 I read this as logically. I haven't won an argument either.

 Well, if you enjoy a good beating, that's a plus?

 Kill it with fire

 better save a few of those oblivious-internet-outrage bucks for when you scroll down to "Rob Warner races a rally car" my dude. Wouldn't want you to get to that one skint

 At least it left Tom a reasonable excuse!

 @olly76: He did look fit AF during those haydayze though.

 @likeittacky: Brother is a stealth fighter, didn't even know he was an XC pro. Bet he's still fast even by Squamish standards.

 @50percentsure: Same here, that was a surprise to find out ! I'm curious though, was he Pro or just racing there as a junior perhaps ??