B’Twin Ultra 920 review

French superstore value packed race machine

Our rating 
4.0 out of 5 star rating 4.0
GBP £2,000.00 RRP

Our review

A top class race machine that’s top value for money too
Skip to view product specifications

We have to admit constantly being surprised by French sports superstore Decathlon’s output. Whether its great value clothing or brilliant budget bikes courtesy of its B’Twin line, the retailer almost always seems to get things right on the money.

  • Highs: Low weight, great price, and an exciting bike to ride
  • Lows: Front-end stiffness means buzzy vibrations to your hands
  • Buy if: You want a bit of Gallic design flair at a great price

The Ultra range also shows that it’s not just value Decathlon is big on – it’s quality too. The Ultra is designed in house by a talented team and a head designer who has the likes of French superbike manufacturers Look on his CV.

You can see some of Look style design cues within the Ultra; its blend of swoopy lines and geometric tubing shapes is all so very Gallic. The chassis itself is a light one, and at just 1200g for the frame and fork combined its one of the lightest you’ll find at this price.

The frame’s understated black graphics on black carbon hide plenty of bang-on-trend details. The cable routing is all internal and there are further nods to aerodynamics in the bladed fork, blended-in down tube shape and the under-chainstay direct-mount rear brake.

At the back the boxy chain- and seatstays give the impression of stiffness, and mated to the square-shaped dedicated seatpost we’d expect a tough rear end. Thankfully the opposite is true; in fact we were impressed with the back end’s ability to smooth out rough surfaces. It has enough compliance (aided by an excellent saddle) to keep us nice and comfortable even on the poorest surfaces.

A slightly buzzy front end proved the only letdown during testing – we’d recommend fitting wider tyres:

A slightly buzzy front end proved the only letdown during testing – we’d recommend fitting wider tyres

Sadly the front end can’t quite live up to the back. When we tested the Ultra 940 last year its Kysrium wheels were shod with bigger 25mm tyres. On this model it’s 23c rubber – and this has increased the amount of buzz that gets through to the stiff Deda aluminium cockpit. It’s not a dealbreaker, but we did get a bit of telltale palm numbness after extended miles on crappy roads.

The bike’s shape is true Grand Tour stuff – the wheelbase, at just over a metre, combines well with a low (but not overly low) front end thanks to its 175mm head tube on our size large test bike. The 73-degree head angle and steeper 73.5-degree seat continue the racing outlook of the Ultra.

As with the geometry, the gearing with its compact 50/34 and close-ratio 11-25 is also aimed towards racing. But all this apparent aggression is balanced by the decently long wheelbase, which does a good job of preventing the Ultra from getting too twitchy when you’re out on the road. Push the Ultra through a tight set of bends on a fast descent and it flows with ease. It always feels composed, but reacts to your inputs instantly and is never unstable on the limit – a neat balancing act.

On the climbs the low weight and light wheels in the form of Mavic’s Kysrium Elite S – just about the very best you can expect for this money – all help. If we were honest we’d have preferred a slightly wider cassette, perhaps an 11-27 or 28, though stronger climbers won’t have such reservations (maybe we should just man up a bit).


On the whole the Ultra is a truly fine machine: it’s very well priced, looks and rides very well. Yes it’s a little buzzy at the front but that could be addressed by switching to 25c rubber. It’s hard to find such a polished and well-equipped race bike at this price, full-stop, and to think you can find this in a shop that also sells yoga mats, skateboards and swimming trunks is pretty remarkable.

Product Specifications


Name Ultra 920 (15)
Brand B'twin

Brakes Shimano Ultegra
Cassette 11-25
Cranks Shimano Ultegra 50/34,
Fork Carbon
Frame Material Carbon
Front Tyre Mavic Yksion Pro 23c
Handlebar Deda RHM02
Rear Tyre Mavic Yksion Pro 23c
Saddle Fizik Arione
Stem Deda Zero2
Weight (kg) 7.45
Wheelset Mavic Ksyrium Elite S
Frame size tested L