Planet X RT-57 SRAM Red Road Bike

Constructed from Mitsubishi high-modulus carbon fibre, the RT-57 boasts bang up-to-date features like a tapered steerer tube and wide, large-bearing BB30 bottom bracket. The tapered steerer stiffens up the whole front end of the bike, improving handling at speed and through corners.

It also makes for a larger down tube and the BB30 bottom bracket helps at the other end too, improving the torsional rigidity of the frame and increasing its stiffness against pedalling.

And here's a tech secret other manufacturers won't tell you when they're blathering on about how smooth the inside of their carbon frames is: a large lower headset makes it easier to pull out the silicone mandrel used to mould the frame and get that smooth internal finish.

If you're asking "Why carbon?" its big advantage over aluminium is that a carbon fibre frame is a pound or more lighter. It also gives a more comfortable ride because of the shock-damping qualities of the material, despite being stiffer against pedalling forces.

What it all adds up to is a quick, stiff road frame suited to fast sportives, shorter Audax rides and racing on quick, twisty courses. It eats hills for breakfast and your mates for lunch and dinner!

RT-57 fit and handling

Traditionally, Planet X road frames have either been very racy, like the Team Aluminium, Pro Carbon, or the new N2a, or very practical like the Kaffenback.

The RT-57 fits in between the Pro Carbon and the N2a, but off to one side. Those two bikes have our classic, long-top-tube road racing geometry. This makes for a bike that's fast and surprisingly comfortable for long rides, if you're flexible enough that it fits you.

The RT-57 is a little shorter for any given size, so if you're not long in the arms and body, or as flexible as a top pro, it'll fit better. But it's still fast and light.

One upshot of all this is that the RT-57 is not is a 'sportive' bike in the sense of the long-head-tube bikes that usually carry that label. We've noticed that a lot of people set up that style of bike with a flat stem to get a quick position. If you don't you can end up with a bike that has so little weight on the front wheel it won't go round corners properly. We'd rather make a bike that handles right.

Of course you can still use the RT-57 for sportives - or anything else. Racing, club rides, training, beating everyone else to the office. It's an all-round road bike at a terrific price.