Marathon racer Katie Lennard weighs in on 120mm forks & dropper posts

#WhichIsFAster? “Bar budget and race performance this is not a hard question – 120mm is a better ride all round. Buttery smooth, plush, luxurious come to mind.

So what exactly are we comparing? In my case, it’s the Fox 32 Factory step cast with Fit4 damper vs. the Fox 34 Factory step cast with Fit4 damper. The difference in weight is 200 grams. On the mountain, compared to the 100mm the 120mm fork eats rocky descents, and is more forgiving of rider error; often overlooked in a longer travel fork is technical climbing ability – of course it’s not going to help you – at all – on relatively smooth terrain but on seriously rocky stuff it definitely takes the edge off. You don’t get that jarring dead-stop effect that is often the final straw that flicks you off your bike and on those sections once you’re off, you’re off. I can already hear those expensive carbon soles crunching through the Attakwas kloof.

So, a 120mm feels great, but what about race performance? Will it make you slower? Here I should leave a little disclaimer that this is not a perfectly controlled experiment but it’s extremely close, as good as it gets with actual race data. Before comparing my data with and without a 120mm fork I better tell you how this all happened in the first place. Like most XC/marathon racers I’d always been focused on getting my bike as light as possible. Yet, in August 2018 James and I packed away our trusty race machines (Trek Top Fuel 9.9s) in favour of 13kg Trek FuelEXs. At that point, I dearly needed a break from disciplined, structured training. No power meter, no heart rate monitor, no zones, just the big blue sky above and the trails below. British Columbia trails. Best. Holiday. Ever. You really want to go there if you ever have the opportunity – but not with your marathon bike. Anyway, by the time we got back to SA my short travel bike was like lettuce to a dog – ‘langtand’ as we say in Afrikaans.

At that stage I was fully prepared to be a bit slower in favour of a more fun bike. But, I also can’t help myself – I’m extremely detail-oriented and am constantly chasing performance optimization so I just lost the weight I added to my bike in body weight, butter on both sides thank you very much. Besides, the Fox 34 Factory step cast fork isn’t exactly heavy. It’s lightweight and race-ready, and with a final nudge from the very knowledgeable boys at The Gear Change I added some otherwise very expensive 120mm candy to my race bike. I’ve raced with it ever since and I don’t think it’s slowed me down on most races.

So, back to the data then. We’re looking at the Piket-Bo-Berg one day race – which is as MTB as it gets, 63km of single track with plenty rocks in between. It’s tough, but massively rewarding. Like trail master Rickus says ’No good downhill goes unpunished’. Record average (male) speed for this race is 20.9km/h by Matt Beers, so this is true mountain biking. Apart from the 100mm fork in 2017 vs. the 120mm fork in 2018 all other factors remained constant as far as I can tell except it was a bit muddy/windy in 2018.

Having had the privilege of riding these otherworldly trails since 2015, I knew the trails well by 2017 at which point our experiment starts. In 2017, I raced a standard Top Fuel 9.9. In 2018 the only thing that had changed was the 120mm fork (no dropper post yet, which in 2019 would add another 410 grams to my current bike, which weighs in at 11.6kg with all the trimmings, and is worth every gram). Coming back from BC we had ridden a fair amount but I hadn’t done any specific training in over two months so I went in with low expectations. To my surprise and amusement, I rode exactly the same time as the previous year when I was training ‘properly’. The course was exactly the same between years and if anything it was a bit muddy and windy in 2018. And, I didn’t have to produce more power with the slightly heavier bike for the same race time, in fact slightly less. In 2017: 3.33W/kg average power, 3.76W/kg NP. In 2018, 3.27W/kg average power and 3.73W/kg NP.

So will it make you faster? Seemingly not, but maybe… On this type of terrain it, however, won’t make you slower, and its 100% more fun than a 100mm fork.

What about ultra-endurance and stage racing? My dad has this old 1970-something navy blue Toyota bakkie, the one with the red stripe down the side. She’s called Pandora. Well, driving Pandora for a picnic on the mountain is cool but driving from Cape Town to Mozambique in one go? It’s bronco bro.. (sorry dad for insulting your beloved blue bakkie in public). The point is that you will spend more energy stabilizing on a 100mm bike on rough terrain. Energy, you might have sent to your pedals had you had a plushe 120mm model? As a racer do you need a 120 for Sani2C or W2W – no I’m pretty sure you’re better off shaving the extra weight. Do you need one for Eselfontein, Tankwa Trek, Attakwas or Piket-Bo-Berg? Well, need is a strong word but if it’s going then yes please! Yes to better comfort, fun AND speed.

I have a hunch, one that can’t be measured unfortunately, that for rough terrain ultra-endurance racing, especially stage racing, a 120mm will save you in the end; your power meter won’t tell you how much energy you’re spending away from the pedals so that’s just my two cents. The Cape Epic next year promises to have plenty of rocky monsters perhaps just waiting to be tamed by a 120? So what do you guys reckon, should I stay on a 120mm or go super light next year?

Happy riding, see you on the trails!” – Katie Lennard



Katie in action at the Swiss Epic & Attakwas


| IMAGES: Supplied by Katie via zcmc & Swiss Epic |


No comment yet, add your voice below!


Add a Comment

Your email address will not be published. Required fields are marked *

Comment *
Name *
Email *
Website