What type of mountain bike is best for an off-road triathlon or duathlon?

Got an off-road race coming up and wondering which is best for the bike leg, a hard tail or full-suspension mountain bike? Bike experts Rob Banino and Nik Cook weigh up the odds

Published: November 13, 2017 at 1:58 pm

Rob Banino says:

A full-suspension MTB, with all its springs, linkages and travel, looks like the ideal tool to smooth out rough, off-road tracks. And it is, if you’re planning on riding over ‘extreme’ terrain – anything involving big boulders, bigger drops and vertical slopes. But while the trails at a typical off-road multisport event are often technical, they’re rarely extreme. As such, a hardtail (a rigid frame with a suspension fork) is almost always the best option.

Why? Let Jez Cox, head coach at howgoodcouldibe.com and Britain’s top off-road duathlete, explain: “A hardtail will always be lighter and better at ensuring the majority of your power transfers from the pedals to the trail. Off-road triathletes don’t need more than 100mm of travel in their forks. That’s enough to absorb any bumps, but, more importantly, bikes designed for more travel will have much slacker head and seat tube angles, which makes it harder to get into an efficient and powerful pedalling position.”

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Nik Cook says:

The first consideration is budget. If you’ve less than £1,500 to spend, I’d go hardtail every time. It’ll be far lighter than a comparatively-priced full susser and have a better spec. Even if you’re happy to part with more cash, my leaning would still be towards a hardtail, though.

For most cross-country courses – and for the majority of off-road tri and du courses – you certainly wouldn’t be at a disadvantage on a hardtail. And, if there’s lots of non-technical fire-road climbing, it’ll give you an edge. At Human Race Off-Road Duathlon Series, most of the top racers were on hardtail 29-ers, and I’d recommend opting for a big wheeler too. On XC-type courses, the bigger wheels are a real advantage. And don’t believe the naysayers who reckon they’re only for tall riders; several top female World Cup XC racers, including Emily Batty who’s only 5ft3in, successfully ride them.

With MTBs, feel and handling are everything, so I’d strongly advise test-riding a few before you buy. I’d also factor into your budget scope for a wheel upgrade. Stock wheels on 29-ers are often a bit heavy and flexi – an upgrade to a lightweight, hand-built set that you can run tubeless will tangibly elevate the bike’s performance. You don’t need to spend a fortune (£500-£600 will make a significant difference) and you can keep your old wheel set-up for foul conditions and training.

Obviously, having an appropriate bike will benefit performance, but off-road course conditions can change dramatically depending on the weather, so having an appropriate set-up is just as important. “The harder and rockier the ground, the more a wider tyre will help,” says Cox. “A great all-purpose choice is a tyre that has a low, ‘file’ tread pattern in the middle and then bigger ‘teeth’ at the edges for cornering.”

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