Yearly Unbound Gravel will get larger and the fields get sturdy. Parallel to that progress is the technological pursuits of the racers and corporations which are 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 take a look at that’s equal elements velocity and sturdiness. With that steadiness, each rider appears to be like for an edge to swimsuit their driving model, the course calls for, and what they hope to attain on race day.
Questions like: what are the greatest tires; what’s the proper gearing; and, what are the appropriate clothes all stay open for dialogue.
Thus, with just some days to go earlier than the large 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 selections that would give benefits, we cannot identify names, however belief us once we say the vary of responses was broad.
Tires – larger throughout the board
(Picture credit score: Anne-Marije Rook)
The one largest change at Unbound this yr shall be a large enhance within the dimension of tires amongst the contenders for victory. There have been some indicators of tire dimension creeping up final yr, however finally the mud negated a few of those that had 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 lots of extra rocks, no matter how a lot precipitation comes within the leadup into the occasion, 2024 will see the pivot towards large 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 had been essentially the most frequent reply when it got here to the dimensions of treads riders can be operating. Some remained under the 50mm threshold, together with some of the well-established gravel execs, Ted King, returning to his tried and true setup of a 44mm slick tire with a sturdy casing.
A very good 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 driving an unreleased model of the In a position 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 selection in setup is consultant of most of the broader traits that we see heading into Unbound.
However, don’t anticipate 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 provided an important clarification of what he was taking a look at for Unbound which was gravel tires round 50mm in width however with very shallow tread patterns. This enables riders to journey large rubber whereas amassing much less mud and likewise 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 Images)
Consistent with the evolution of tire dimension is the shifting opinion on tire inserts. At Unbound lately, tire inserts have been touted as a key for any rider to get by the race with fewer punctures.
Tire inserts had been first popularized on mountain bike tires and basically permit riders to run decrease strain with out the identical threat of flat tires which come from from rocks pinching the tread of the tire in opposition to the rim. When operating a 38-42 mm tire on gravel particularly, the impacts from the sharp, large gravel you see within the Flint Hills could be mitigated by a mixture of the insert and low strain, in idea.
In observe, nevertheless, the outcomes are combined. Engineers of each tires and wheels have raised questions concerning 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 realize that traction is the tire’s potential to deform round a few of the bigger objects through a “supple” sidewall that may flex and compress beneath essentially the most sturdy rubber casing in the course of the tire.
(Picture credit score: Vittoria)
Inserts change the best way that the sidewall can transfer, with the density of the shape decreasing the quantity of air within the tire. Whereas this does permit decrease pressures in a smaller tire, air is extra compressible than foam which suggests the tire will not have the ability to 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 might have and are a typical incidence amongst the sharp rocks round Emporia.
What’s extra, with large 50mm plus tires, the amount of air adjustments the probability of a pinch flat, and will give a lot of the riders the boldness to go away the inserts at house. Nonetheless, 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 large 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. Nonetheless, gearing ought to be an in depth second as small tweaks and selections round one’s drive-train could make large variations over 200 miles of racing.
With that massive distance to think about, any added effectivity that would appear marginal for different races turns into large 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 taking a look at larger chainrings and 1x setups as efficient instruments for decreasing 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 boys’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 nicely for these driving both the SRAM 1x drivetrains or the Shimano GRX mechanical setup. With Shimano rolling out its new GRX di2 drivetrain just lately, there’ll nonetheless be a powerful illustration of 2x at Unbound. Nonetheless, with the chaos of the mud recent in everybody’s minds the simplicity of the 1x setup shall be well-liked no matter what groupset a rider is sponsored by.
Finally, the transfer to greater chainrings because the velocity of those races appears pure. The extra attention-grabbing query is how large one can go as time trial tech and testing within the WorldTour have proven how efficient large chainrings could 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 help 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 shall be within the 20-30 mph vary the place a 50t or perhaps a 52t chainring provide a sequence line with considerably larger effectivity. It is laborious to say what the precise watts saving can be given all of the separate variables, however evaluating a 46t chainring to a 52t chainring might see the bigger possibility 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 large 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 help stations the place they’ll replenish meals and liquids. This has triggered the proliferation of hydration packs throughout the aggressive spectrum at Unbound. The added carrying capability for each meals and hydration is important for all riders. Nonetheless, for the entrance of the race, it’s a wonky piece of apparatus that reduces a rider’s aerodynamics and the elite subject has been taking a look at methods to alter that calculus yr after yr.
In 2024, a few of the largest biking clothes manufacturers are lending their experience to construct a equipment that fits these particular wants.
Castelli is the primary model to launch its Unbound equipment 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 equipment was proven off by Ben Delaney, a biking journalist who’s sponsored by Castelli, and is really the primary of its sort to be constructed across the hyper-specific wants of gravel races like Unbound.
The jersey shouldn’t be precisely revolutionary as riders have been stitching bladders into jerseys for a number of years now, however it’s the first official providing from one of many large clothes manufacturers.
It’s also in all probability not going to be the final bespoke equipment launched for Unbound as rumblings of particular equipment from different high manufacturers who accomplice with high gravel riders have been kicking round as nicely. Whereas the main points stay below lock and key, Castelli’s providing of a race-style jersey with a devoted house for a bladder shall be replicated once more by different firms 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.
