Decathlon B’Twin Ultra 900 CF 105

The Ultra CF 900 is further evidence, if any was needed, that B'Twin knows how to build awesome-riding race bikes which offer excellent stiffness, handling and speed while also managing to be unbelievably comfortable. Bung in a sub-£1.5k price tag for a full-carbon frame and fork, Shimano 105 groupset and Mavic wheels, and it really is an exciting package.

• Pros: Excellent comfort levels, stiff bottom bracket area, fun ride
• Cons: Lighter wheels are needed to really release the full potential of the frameset

With its 'UCI approved for racing' logo on the top tube and its geometry, I was really expecting the Ultra CF 900 to be a no-nonsense speed machine, sacrificing comfort for performance, especially when you take into account those huge tube profiles. In use, though, it is completely the opposite.

> Find your nearest Decathlon store here

The ride is sublime, absorbing pretty much everything the road surface can chuck at it, so you just waft along at a very impressive pace, smashing mile after mile without effort.

B'Twin says that the frame was specially designed for the most demanding climbers and sprinters, and its stiffness is centred primarily around that massive bottom bracket, chainstay and down tube junction. No matter what I could throw at the Ultra CF when out of the saddle, I couldn't get even the slightest hint of flex anywhere in the bottom half of this frame.

To get this level of stiffness in the frame while still allowing enough 'give' in other places shows some clever frame design and use of the various carbon grades used in its construction.

The handling is sweet too. The head angle is 73 degrees, which isn't massively steep for this kind of bike, but it's enough to keep the front end quick and precise without instilling any form of twitchiness. The Ultra CF is a fun, quick-handling machine to ride, no matter what your level of ability; it flatters.

The fork stiffness matches that of the frame, so banking the bike over from side to side and under heavy braking never finds any level of understeer or vibration through the legs.

You aren't always going to be smashing it down hills, though, so it's great that the handling works a treat when you're just cruising along at a steady rhythm too. A lot of bikes that are great in the bends, the harder they are pushed, can become a little bit of a handful when things calm down, but the B'Twin remains balanced at all but the lowest of speeds.

It's not going to cut through the rush hour traffic as smoothly as a commuter bike, but flat cornering and meandering through the lanes is a relaxing experience and makes the Ultra CF 900 just as much a joy for group rides with buddies as it is on the rivet. It really is a very complete package.

Frame and fork

The Ultra CF 900 is based around the Ultra Evo Dynamic frameset, which in this medium size has a claimed weight for the frame of 850g and just 320g for the fork, which is impressive. You can buy the frameset package for £999.

I've mentioned the tube profiles already but it's safe to say that they follow the common theme of chunkier at the front and bottom, with the upper tubes introducing a little bit of extra flex for comfort.

The head tube is a boxy affair with various edges and profile changes so that it can blend into the Evo Dynamic fork.

Its size also allows for the huge, square-profiled down tube, which shifts shape down towards the bottom bracket to cope with the change of forces between the steering and pedalling at the business end.

The top tube is wide and flat at the front before it narrows towards the seat tube, and the curve from front to rear should tame the stiffness a little.

The bottom bracket shell is press-fit 86, which won't be everyone's cup of tea, but on race frames the benefit is obvious. Pressing the bearing cups into the frame means the shell can be wider, the same as a standard shell including outboard bearing cups, so you still keep the same Q-factor, the distance between the crank faces. This allows for a wider down tube, seat tube and huge chainstays for power delivery.

The downside of press-fit bottom brackets can be creaking if the tolerances between frame and bearing cups are a little sloppy. With next to no rain here for weeks, it's been tough to test.

The frame uses its own specific carbon seatpost in a five-sided design, so if you like to upgrade your components you are going to be out of luck here. It's held in place by an internal wedge system for a clean look and it certainly works as I had no slippage issues at all.

Other neat little details include the mounting point on the bottom bracket shell for the included chain catcher to avoid the risk of chainsuck wrecking the frame.

You get full internal cable routing from front to rear and it's well placed to avoid any frame rub. The rear brake exits on the top of the top tube rather than the side, which means it stays close to the seatpost avoiding irritation on your thigh.

When it comes to mounting points, you get two sets of water bottle cage points and that's it; it's a race bike after all, so don't expect mudguard or rack mounts.

The dropouts on the frame and fork look to be carbon fibre, which loses a little bit of weight, but you do get a replaceable mech hanger at the rear should you drop or crash the bike.

The rest of the fork is carbon fibre too, from leg to steerer, and it is a cool looking design with its chunky legs at the crown along with the recesses for the direct-mount front brake calliper.

Geometry and sizing

Geometry-wise, the Ultra AF 900 is very racy, even though it doesn't feel that extreme in use.

This medium model has a seat tube length of 490mm, top tube of 560mm and a shortish head tube of 150mm.

With stack and reach figures of 548mm and 398mm respectively, the ratio here is just 1.37 which is very race orientated. Race bikes are generally around 1.4, with endurance bikes sitting at a more relaxed 1.55.

The Ultra CF is available in sizes XS to XL, with top tube lengths of 530mm to 585mm.

Groupset

The Ultra CF 900 comes with a full Shimano 105 groupset throughout, which is nice to see. At this price point it's still not unheard of to see a scrimping on the brakes or chainset.

The gearing is aimed at the performance rider, as you'd expect, so B'Twin has gone for a 52/36 semi-compact chainset option up front, with an 11-28, 11-speed cassette at the rear.

It's a decent spread of gears for the type of riding the Ultra is aimed at, but one thing I do like about the way that B'Twin specs its road bikes is to always fit a medium cage rear mech.

The short cage 5800 105 option, according to Shimano, only has the range to go up to a 28-tooth sprocket so if you want lower gears you'd need to swap the mech. With this medium cage as standard you can swap to an 11-32, for instance, without any setup issues.

The new R7000 105 groupset is now available, but this 5800 version is still a good 'un so if you can pick up a bargain it's well worth the punt, as you can tell by my review here. The shifting is precise and relatively light to the touch and the braking through the dual-pivot callipers is spot on.

Both the mechs can handle shifts under a reasonably heavy load without too much grumbling, but best of all is its reliability and durability.

The groupset I reviewed in the link above is coming up on four years old and has covered the best part of 25,000 miles, with pretty much all of that being in the winter as it's on my Kinesis T2 do-everything bike. I've changed the chain and cassette a few times, but everything else is still running smoothly with very little wear.

Wheels and tyres

The 900 gets a set of Mavic Aksium wheels, which is pretty good for the money. They are solid performers and a good entry-level set of wheels especially if you want something durable and smart looking without worrying too much about weight.

They aren't the lightest, nudging 2kg once the rim tapes and skewers are added, which does take the shine off the Ultra's frame and fork a touch. I ran the same bike with a sub-1,500g set of deep-section carbon wheels and it really unleashed the quality of the frame.

As I say, though, it's good to see a wheelset of this quality at this price point. If taking to the pothole-strewn back lanes is your thing rather than a day in the mountains, you aren't going to be complaining.

Mavic supplies its own tyres with its wheels as part of a package these days, and I'm glad to say they've improved over earlier versions. Original models of the Yksion weren't very good when it came to puncture resistance, and grip was mediocre in the dry to downright sketchy in the wet. These are pretty impressive. The grip is much improved, as is their ability to resist the puncture fairy. They roll pretty well too, so I'd be in no real hurry to swap them out.

Finishing kit

Up front you get a basic but decent aluminium alloy handlebar and stem combination. They are both stiff in use but the frame manages to damp things down a bit so it doesn't bring any discomfort to the ride.

On the medium model the handlebar is 42cm wide and the stem is 110mm in length, but this changes depending on the size of the bike. The bar has quite a shallow set of drops, which means they are usable by pretty much anyone.

Atop that frame-specific seatpost is a B'Twin branded saddle and I must admit on first impressions I didn't think I was going to get on with it as it's quite flat in profile. In use, though, it was fine because it has plenty of padding without being squidgy, plus it also has plenty of length to let you move forwards and back depending on how you ride.

Value

B'Twin being the in-house brand of Decathlon sports stores means it can employ a direct-to-consumer model which ultimately keeps the costs down; and if you happen to live near a store, you can get to see the bike in the flesh and throw a leg over it for size.

> Decathlon road bikes – a buyer’s guide to the B’Twin range

This Ultra CF 900 package comes in at £1,399, which is really good value for money when you take into account the quality of the £999 frameset.

Canyon has to get a mention when it comes to direct to consumer sales and its Ultimate model is probably the best comparison. The Ultimate CF SL 7.0 model is a close match to the B'Twin, with a carbon frameset, Shimano 105 and Aksium wheels for £1,449 plus postage, which adds on another £30 or so.

It does get an upgraded set of Continental tyres and a Fizik saddle, though, and we've always found it to have a good ride, similar to that of the B'Twin, a beautiful combination of comfort and speed.

> Buyer's Guide: 12 of the best £1,000-£1,500 road bikes

Another very good carbon fibre-framed race bike at a very good price is Focus's Izalco Race range (I tested the Shimano Sora model here), with the 105 model priced at £1,399, the same as the B'Twin.

For the Ultra CF 900 to be uttered in the same circle as both of these bikes is praise indeed.

A carbon-framed bike with 105 can easily cost much more: take the Trek Emonda SL 5, for instance, which costs £1,800.

If you want the Ultra CF in a different setup you can go for the 920 with Ultegra, Deda finishing kit, Mavic Cosmic Carbon wheels and a Fizik saddle for £1,999. The 920 is also available in a Campagnolo Potenza build with the same finishing kit but Campag Zonda wheels for the same money.

For ultimate bling, though, there is the Dura-Ace model with Zipp 303 wheels, carbon handlebar and an upgraded Fizik colour-coded saddle for £3,499. A lot of money yes, but far from expensive for what you are getting.

Conclusion

The Ultra CF 900 is built around what can only be described as an excellent frameset. It's a real rider's bike with loads of feedback from the frame and fork no matter whether you are just cruising along or smashing it through the technical bits.

Comfort, as I've mentioned, is pretty special too.

It's a sensible entry into the performance road world and the frameset is ripe for upgrades as you improve.

Verdict

A beautiful frameset that excels in comfort and performance wrapped in decent components at a very competitive price