B'Twin Ultra 900 review

We put Decathlon's climbers' bike through its paces

Cycling Weekly Verdict

The B’Twin provides a ride which really defies its £1,600 price-tag.

Reasons to buy
  • +

    Very light for this price bracket

  • +

    Neat internal cable routing

  • +

    Di2 compatible frame

  • +

    A joy to ride

  • +

Reasons to avoid
  • -

    Wheels are prone to flexing when sprinting

You can trust Cycling Weekly. Our team of experts put in hard miles testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.


The brand markets its B'Twin Ultra 900 as its climbing bike, so it is no surprise that the frame hits the scales at only 850g — seriously light for a bike of this price.

Unlike the other bikes on test, the B’Twin largely uses box-profile tubes which may not be to everyone’s liking, but are certainly an improvement on the bulbous tubes seen on other bikes.

The B’Twin’s lines are kept clean by the neat internal cable routing. The frame is also compatible with electronic groupsets, should you wish to upgrade in the future. As a neat final touch, the seat clamp is beautifully integrated into the top tube.

The B’Twin Ultra 900

The B’Twin Ultra 900's lines are kept clean by the neat internal cable routing


The B’Twin comes equipped with a full Shimano 105 groupset, though pedants may wish to point out that the exception to this is the KMC chain. The 52-36t semi-compact chainset is new territory for 105, but it performs superbly and is the natural choice for riders looking for gearing that is at home in a crit as it is in the high mountains.

The 105 brakes are direct-mount versions, with the rear brake positioned beneath the bottom bracket. The aero benefits may still be questionable, but aesthetically there’s no doubting its appeal.

Deda stem and bars, together with a Fizik Arione saddle mounted to a bespoke seatpost, complete the package, with the B’Twin wheels the only real concession to price.

BTwin Ultra 3

The full Shimano 105 groupset includes a mid-compact chainset


Riding the B’Twin Ultra 900 is nothing short of a joy. Put an exotic-sounding Italian name on the down tube and an extra grand on the price tag and there would still be many riders happy to own this bike.

The power transfer is good and the handling precise, while comfort on rough British roads is improved by the inclusion of a carbon seatpost. The only improvement we’d like to see would be a wheel upgrade, as the B’Twin wheels were prone to flex when sprinting.

But it is in the hills where the B’Twin really comes into its own. The lightweight frame is constantly willing you to attack the steepest gradients, with the press-fit bottom bracket and boxy chainstays allowing you to dance on the pedals without paying a penalty in flex.


The B’Twin provides a ride which really defies its £1,600 price-tag, and if you’re after a reasonably priced bike that will be as at home in long, mountainous sportives as it is in your local crit series, there’s no need to look any further. The extra details such as the direct-mount brakes and integrated seat clamp really seal the deal. See Decathlon's site for more on this and the rest of their road bike range.

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