Bike Check: Milan Vader's Cervelo ZFS-5 Short Track Bike
Milan Vader has gone with an unconventional modification on his Cervelo ZFS-5 for his short track racing. The rear shock of his ZFS-5 has been replaced with a fixed linkage, eliminating the rear suspension element. This modification aims to optimize the bike's performance for the demands of short track racing, which typically involves shorter, more intense laps on relatively smooth terrain. By removing the rear suspension, the bike may gain increased pedalling efficiency and responsiveness, allowing for quick accelerations and efficient power transfer.
This experiment with the fixed linkage is an interesting concept, and it demonstrates Milan Vader's willingness to push boundaries and find unique solutions to optimize his performance in specific race scenarios.
This experiment with the fixed linkage is an interesting concept, and it demonstrates Milan Vader's willingness to push boundaries and find unique solutions to optimize his performance in specific race scenarios.
Milan Vader // Jumbo-Visma
Age: 27
Hometown: Middelburg, Netherlands
Height: 1.73m
Weight: 63 kg
Instagram: @milanvader
Age: 27
Hometown: Middelburg, Netherlands
Height: 1.73m
Weight: 63 kg
Instagram: @milanvader
Cervelo ZFS-5
Frame: Cervelo ZFS-5
Shock: Custom aluminum link
Fork: Rockshox SID 100mm
Wheels: Reserve 28 XC 29"
Tires: Vittoria Terreno Graphene 2.0
Drivetrain: SRAM Transmission
Brakes: SRAM Level ULT
Cockpit: FSA SL-K Pro handlebar & FSA SL-K Drop Stem
More info: Cervelo ZFS-5
Frame: Cervelo ZFS-5
Shock: Custom aluminum link
Fork: Rockshox SID 100mm
Wheels: Reserve 28 XC 29"
Tires: Vittoria Terreno Graphene 2.0
Drivetrain: SRAM Transmission
Brakes: SRAM Level ULT
Cockpit: FSA SL-K Pro handlebar & FSA SL-K Drop Stem
More info: Cervelo ZFS-5
The Cervelo ZFS-5 has been specifically designed to meet the demands of modern XCO and short track courses, which require a balance of efficient pedalling, agile handling, and the ability to tackle rough terrain. With a 67.8-degree head tube angle, the ZFS-5 provides the necessary precision for fast sprints and close-quarters racing, giving riders the confidence to navigate elbow-to-elbow encounters.
The customized version of the Cervelo ZFS-5 that Milan is using features a unique machined linkage in place of the standard Rockshox SID LUXE shock. This link is specifically designed for Milan's short track racing needs. While the current aluminium link is a prototype, Cervelo plans to replace it with a carbon part in the future. However, the final version will undergo some changes. The goal of the link is to create a hardtail-like feel and enhance power transfer for Milan while maintaining the familiar touch points he is accustomed to from his bike in its standard configuration. The link is designed to position the bike at Milan's desired 20% sag point.
Milan and the team are really happy with how the bike feels with the aluminum link, and they have been exploring further development of this concept. The upcoming carbon link will incorporate a flip chip in the rear, allowing the team to fine-tune the virtual sag position. This adjustment capability will enable them to modify the bike's geometry for different tracks, optimizing performance based on specific race requirements.
Right now you might be saying, 'I can do this by locking out my rear shock, though,' and you make a valid point. While it may be tempting to simply lock out the shock to achieve a similar effect, there are some key differences to consider. When you engage the lockout on a standard shock, there can still be some residual flex in the bike, typically around 5-10mm, depending on the specific bike and shock setup.
In contrast, the purpose-built fixed link provides a beautifully simple solution with zero flex. By eliminating any potential flex, the link ensures optimal power transfer and a more rigid feel, which can be advantageous for certain racing scenarios. This allows the bike to excel in short track then with a quick turnaround be ready to race XCO as well.
Milan's short track bike is equipped with a 120mm Rockshox SID suspension fork. The fork features a remote lockout, allowing Milan to quickly switch between open and locked positions for efficient climbing and sprinting. The fork is set at 66psi, with one token installed. The rebound setting is adjusted to 6 clicks from the closed position.
Milan also makes use of RockShox's TwistLoc remote lockout to allow him to make changes to his fork with minimal movement of his hand.
When it comes to brakes Milan uses an brand new set of SRAM Level ULT brakes with the new levers.
Milan's cockpit setup is provided by FSA, with the SL-K Pro flat carbon handlebar cut down to a width of 720mm. It is paired with an FSA SL-K Drop aluminum stem, which has a -20 degree angle and measures 100mm in length. Milan takes advantage of the SRAM MatchMaker system to mount his shifter and dropper remote directly to his Level brakes, ensuring a clean and compact control setup.
Milan's cockpit is finished off with a set of foam grips.
Milan's Team Jumbo-Visma are sponsored by SRAM, with the brand providing him with their latest Transmission AXS wireless electronic groupset.
Milan's choice of Reserve 28 XC wheels with a 28mm internal depth and reinforced spoke holes is geared towards durability and strength while maintaining a relatively low weight of 1387g. The Vittoria Terreno Graphene 2.0 tires with a width of 2.25" provides a balance between traction and rolling resistance. Milan prefers to run a tubeless setup without inserts, but he may use a rear insert for added protection on particularly rocky tracks. His tire pressures of 16psi in the front and 17psi in the rear are subject to adjustment depending on track conditions and weather.
Milan has a Rockshox AXS Reverb dropper post for both short track and XCO racing. This is something that is beginning to be much more common within the World Cup XC field.
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Either way, I'm sure if Nino would install such a link, no one would even notice.
also, loopholes are called loopholes because it's legal. if it weren't we would call it cheating. lol
That would lock the suspension into full droop, allowing no control of the ride height and chassis attitude. The article contains a discussion of why that wasn't done.
That's true, but if someone is going to the trouble of removing shock internals and replacing them with rods, or having a selection of shocks just to lock out these shocks, they might as well create a rigid link and do away with the shocks altogether, which is exactly what we're looking at.
I'll admit to kind of being a fan of the wild rule 'circumventing' that Porsche did on the 935 'Moby Dick' but it wasn't really good for racing, more like a technical exercise in legality. And it turned out to be a loophole that was quickly closed.
I'm more of a fan of the Audi diesel LeMans cars where there was true rule favorability towards the 'wrong' type of engine.
@BarryWalstead: As long as there's been competition, people have been playing with the rules - and outright cheating, of course. Sometimes it's a clever, clean advantage, and sometimes it harms the sport. This example from Jumbo-Visma seems like the former, albeit a rather small advantage.
And as I said, media coverage. We can't really say that Milan Vader or Femke Van Empel have been successful in XCC/XCO world cups this year. Without that fixed link we wouldn't even have seen an article with a Cervelo MTB.
Not sure whether it is a media coverage thing. If Cervelo wants to draw attention their full suspension bike, I suppose they'd best do it when it is actually being used as a full suspension bike. I think if anything, allowing their riders to do this is more of a generous move as they should be aware that this is how the bike is getting known and it will be hard to ever sell it to anyone. I'm pretty sure that if a Specialized team rider would want to do this, they simply wouldn't be allowed.
As for the riders, I don't think Milan has ever stood out as a top performer but still in the sub-top. And that's still a valid position to make a career out of I'd say. As for Fem, she's about the same age as Puck and as still an U23 racer she has just finished two elite races. Just looked it up for you. 16th in Lenzerheide, ahead of Kate Courtney and Jolanda Neff and 17th in Nove Mesto slightly behind those two. She's behind them in the overall but that's largely because she doesn't compete in the XCC. Anyway just for reference, what would you consider "successful" for a 21yo rider competing in the elite field?
Look at Ondrej Cink or Thomas Litscher. Both did top 10 in Lenzerheide but not being at the front from the but we only saw them crossing the finish line. Even a guy like Davide Valero storming to top 5 at the end of the race got only a few seconds of air time.
However, when locked-out, there is still some movement. And therefore loss in efficiency. And when locked out, the bike is not at "sag". With this link, they lock it out at sag, so the geometry isn't as affected as using a lock-out.
singletrackworld.com/2011/04/straitline-quickie-stiffie
Regarding costs: Although this link looks fancy and probably expensive, you could achieve the same result at a few grams more weight with some aluminum plates and a band saw. Or they could leave the rocker link in place and just use a chunk of metal - even plywood - in place of the shock if they were on a van-life privateer's budget.
If it was introduced to reduce costs I can’t imagine it actually saves all that much.
“This modification aims to optimize the bike's performance for the demands of short track racing.”
Basically we can’t make a properly efficient bike even when locked out.
Might as well go full 90’s XC and make the thing of elastomer - that would be more interesting.
Wow, this is such lame marketing mumbo jumbo.
What an outside thinker. I mean, no one has ever thought of this before, aka, "hardtail". So essentially, the lockout was "too heavy", and his team is too broke to give him a hardtail, so they contrapted this linkage. So ground breaking.
Well except for the flex in the seat stays.
iykyk
Why not just give the bike a longer front-center so you can get sufficient weight over the front w/o killing the handling?
surely a 30-50mm stem weighs less than that massive thing.
Then they throw lockouts of all sorts onto bikes with barely any travel to begin with, bikes that are already massively efficient and dont need any help.
This really just looks like they're accommodating roadies to make these mountain-ish bikes feel more like road bikes.
Hint: it’s not because the pro racers are wrong.
"because they're a pro, therefore they're experts in bike setup and design".
Not necessarily. They just know what has worked for them in the past.
XC looks like the one area of MTB that's most resistant to innovation. That's why you still have articles written about the author being surprised they're using dropper posts now, when they've been common for the last decade.
I think these XC bikes have horribly short top-tubes and aren't balancing the rider if they need to resort to 100mm stems to get enough weight on the front wheel.
I dunno, maybe make their chainstay's longer to center the rider.
Maybe we'll get to a point where XC racers realize they can still be plenty competitive on bikes that dont contain all sorts of performance and handling compromises just to be sub 20lbs.
Racers are good athletes and sometimes have good insight into bike design. They are however, very biased towards the traditional way of doing things, even when there is no evidence that it's the better way. Ultimately, if it were purely up to racers, we would still be stuck in the 1990s bike designs.
They are literally riding on long, negative rise stems with suspension lockouts, 170mm+ cranks, and many were very resistant to dropper posts and full suspension until recently. These things are all holding them back performance wise.
A mako shark doesn't understand what makes it fast.
XC racers are adopting better handling bikes (65-66 hta, dropper post, shorter cranks) but slowly. They're reluctant to change from what they're familiar with.
People are just a hive mind, and this site in particular is an echo chamber. I don't race XC or DH, I'm a totally average trail rider, but I'm going to trust that these people have at least some clue what they're doing
He's just making his bike perform worse because it "feels" faster. Ultra high tire pressures feel faster too, but like this hardtail conversion, they are also slower.
Messing with the bike this way will also make it feel wrong, ride differently.
If he actually wants to improve performance, put the rear shock back in, get lighter rims, Berd or PiRope spokes, Extralite Hubs, and shorter cranks (145-160mm)
*neither
If this gives him a sprint advantage, whether that’s punching up a climb or the last 100m to the line, it’s worth it.
It actually is a time trial/science experiment. How could it not be?
Tire pressure is not a matter of harder pressure= slower. It is all going to be surface dependant. Harder tires are certainly faster if the surface is very smooth. If the surface is rougher, then softer tires (to a degree) will be more efficient. It's all about finding the sweet spot of the most pressure you can run before you start to lose traction over bumps.
A more comfortable racer is a faster racer.
WC dh racers will prioritize support over being comfortable, because they are strong enough to withstand the forces and impacts for the duration of the race run, and will therefore, go faster, despite not being as comfortable. In an XC race, the race distance/time is longer obviously, but the same theory applies. If the athlete can overpower the discomfort in order to run a "faster" set up for the time necessary to finish the race, then they will come out ahead.
These companies aren't pouring millions of dollars into R&D, just to put their athletes on the back foot and ensure a worse result. That would be stupid and a waste of money. That being said, obviously mistakes can be made, but they are normally addressed with hindsight.