Yearly Unbound Gravel will get larger and the fields get robust. Parallel to that progress is the technological pursuits of the racers and corporations which might be attempting to crack the code of one of many trickiest technological checks in biking.
With its potential for catastrophe round each nook and over each unpredictable rock, Unbound is a check that’s equal components velocity and sturdiness. With that steadiness, each rider seems for an edge to go well with their using type, the course calls for, and what they hope to attain on race day.
Questions like: what are the finest tires; what’s the proper gearing; and, what are the proper clothes all stay open for dialogue.
Thus, with just some days to go earlier than the massive present, we got down to discover this yr’s solutions to these questions throughout the professional fields at Unbound. With these tech selections full of prototypes, soon-to-be-released tech, and choices that would give benefits, we can’t title names, however belief us once we say the vary of responses was vast.
Tires – larger throughout the board
(Picture credit score: Anne-Marije Rook)
The one largest change at Unbound this yr will likely be a enormous improve within the measurement of tires amongst the contenders for victory. There have been some indicators of tire measurement creeping up final yr, however in the end the mud negated a few of those that have been able to go larger. When it rains prefer it did within the run-up to the race final yr, larger is definitely not higher.
However, with a north course that can have much less mud and plenty of extra rocks, no matter how a lot precipitation comes within the leadup into the occasion, 2024 will see the pivot towards huge tires attain its climax.
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In line with our dialog with a spread of LifeTime Grand Prix riders heading to Unbound with aspirations, 50mm tires have been essentially the most frequent reply when it got here to the scale of treads riders can be operating. Some remained beneath the 50mm threshold, together with some of the well-established gravel professionals, Ted King, returning to his tried and true setup of a 44mm slick tire with a sturdy casing.
A superb signal of what’s coming to the gravel world is Payson McElveen’s option to run Maxxis 2.25 Aspen mountain bike tires on the current Rule of Three bike race within the equally chunky terrain of Northwest Arkansas. McElveen, who’s sponsored by Allied, was using an unreleased model of the Ready because the earlier iteration couldn’t maintain greater than a 45mm tire within the rear. With the brand new bike and the selection to go together with an enormous however very quick cross-country tire, his alternative in setup is consultant of most of the broader developments that we see heading into Unbound.
However, don’t count on to see a bunch of mountain bike treads on the beginning line. Alex Howes is sponsored not by a tire firm however as a substitute by an organization that sells a large assortment of tires — Bike Tires Direct. He supplied a fantastic rationalization of what he was for Unbound which was gravel tires round 50mm in width however with very shallow tread patterns. This enables riders to trip huge rubber whereas amassing much less mud and in addition avoiding cuts from methods that could be snagged by an elevated rubber knob.
Tire inserts – on the best way out
(Picture credit score: Snowy Mountain Pictures)
Consistent with the evolution of tire measurement is the shifting opinion on tire inserts. At Unbound lately, tire inserts have been touted as a key for any rider to get by way of the race with fewer punctures.
Tire inserts have been first popularized on mountain bike tires and basically enable riders to run decrease stress with out the identical danger of flat tires which come from from rocks pinching the tread of the tire towards the rim. When operating a 38-42 mm tire on gravel particularly, the impacts from the sharp, huge gravel you see within the Flint Hills may be mitigated by a mix of the insert and low stress, in idea.
In apply, nevertheless, the outcomes are combined. Engineers of each tires and wheels have raised questions in regards to the effectiveness of inserts as they do change the character of how a tire interacts with the bottom it rolls over, whereas riders have anecdotal seen sufficient flats with inserts to be extra hesitant to wrestle the inserts onto their rims.
The change within the opinion round inserts revolves across the nature of gravel tires in comparison with highway or mountain bike treads. Gravel tires work by providing a platform for the rider that contours to the uneven floor beneath the tread. One of many key traits of efficient gravel tires to achieve that traction is the tire’s means to deform round a few of the bigger objects by way of a “supple” sidewall that may flex and compress beneath essentially the most sturdy rubber casing in the midst of the tire.
(Picture credit score: Vittoria)
Inserts change the best way that the sidewall can transfer, with the density of the shape lowering the quantity of air within the tire. Whereas this does enable decrease pressures in a smaller tire, air is extra compressible than foam which implies the tire will not be capable of stretch or deform in the best way it was developed to. With out having the identical pliability within the sidewall, the tire is uncovered to extra cuts on the sidewall that are a few of the most disastrous flat tires a rider may have and are a typical prevalence amongst the sharp rocks round Emporia.
What’s extra, with huge 50mm plus tires, the amount of air adjustments the probability of a pinch flat, and may give many of the riders the arrogance to go away the inserts at house. Nevertheless, ought to it rain as a lot as predicted, tire inserts and 40-42mm tires could be again on the menu as tire clearance turns into an enormous variable to success on the day.
Gearing – single huge rings are in
Keegan Swenson runs a big 1x chainring in gravel races
(Picture credit score: Keegan Swenson)
At Unbound tires are the plain start line of any tech dialogue. Nevertheless, gearing needs to be a detailed second as small tweaks and choices round one’s drive-train could make enormous variations over 200 miles of racing.
With that vast distance to think about, any added effectivity that would appear marginal for different races turns into enormous in Kansas. Moreover, as a result of drive-train effectivity is tremendously impacted by grit and dirt, something to cut back friction will even be compounded over time as riders’ chains will solely get messier because the day goes on. Taking these perimeters into consideration, riders on the elite aspect of the race are larger chainrings and 1x setups as efficient instruments for lowering the flexibility for mud to get in the best way of shifting and, maybe most significantly, permitting for straighter chain strains all through the race.
On the lads’s aspect, this implies 48-50t chainrings have changed the 46t chainrings of previous, whereas the ladies can have extra 48t chainrings on the startline as properly for these using both the SRAM 1x drivetrains or the Shimano GRX mechanical setup. With Shimano rolling out its new GRX di2 drivetrain lately, there’ll nonetheless be a robust illustration of 2x at Unbound. Nevertheless, with the chaos of the mud recent in everybody’s minds the simplicity of the 1x setup will likely be in style no matter what groupset a rider is sponsored by.
In the end, the transfer to greater chainrings because the velocity of those races appears pure. The extra fascinating query is how huge one can go as time trial tech and testing within the WorldTour have proven how efficient huge chainrings may be. Though WorldTour time trials and Unbound appear to be the 2 reverse ends of the spectrum, the teachings are transferable.
Whereas sections like Little Egypt and the punchy climbs heading into the ultimate support station at Council Grove demand a simple gear, these sections make up a a lot smaller portion of the course to the stretches of gravel the place the elites will likely be within the 20-30 mph vary the place a 50t or perhaps a 52t chainring provide a sequence line with considerably greater effectivity. It is exhausting to say what the precise watts saving can be given all of the separate variables, however evaluating a 46t chainring to a 52t chainring may see the bigger choice gaining 2-4 watts of effectivity good points all through the race. Whereas that appears small on paper, over 200 miles the distinction might be large.
Clothes – balancing hydration and velocity
Castelli’s Limitless Professional jersey has a built-in hydration pouch
(Picture credit score: Castelli)
The final huge piece of the puzzle of Unbound tech success is the clothes a rider wears and particularly how one can successfully gas whereas remaining aerodynamic.
With the race retaining parts of its self-supported origins, riders are required to go over 50 miles between support stations the place they’ll replenish meals and liquids. This has brought on the proliferation of hydration packs throughout the aggressive spectrum at Unbound. The added carrying capability for each meals and hydration is crucial for all riders. Nevertheless, for the entrance of the race, it’s a wonky piece of kit that reduces a rider’s aerodynamics and the elite subject has been methods to vary that calculus yr after yr.
In 2024, a few of the largest biking clothes manufacturers are lending their experience to construct a package that fits these particular wants.
Castelli is the primary model to launch its Unbound package over the weekend with a jersey full with a built-in sleeve for a hydration bladder and a strap to carry the hose sewed into the light-weight jersey. The package was proven off by Ben Delaney, a biking journalist who’s sponsored by Castelli, and is actually the primary of its sort to be constructed across the hyper-specific wants of gravel races like Unbound.
The jersey will not be precisely revolutionary as riders have been stitching bladders into jerseys for a couple of years now, however it’s the first official providing from one of many huge clothes manufacturers.
It is usually most likely not going to be the final bespoke package launched for Unbound as rumblings of particular package from different prime manufacturers who companion with prime gravel riders have been kicking round as properly. Whereas the main points stay below lock and key, Castelli’s providing of a race-style jersey with a devoted house for a bladder will likely be replicated once more by different corporations as riders and types alike look to marry the aerodynamic and hydration wants of gravel racing as the game continues to develop and refine itself.
