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Just in: Lapierre Pulsium 700

A cobble-taming endurance bike with a top tube that's designed to absorb vibration

Seen under some of the FDJ.fr riders in this year’s Paris-Roubaix, the Lapierre Pulsium is designed to take on the worst surfaces in comfort while also getting the power through to the road. We’ve managed to get our hands on the £3,099.99 Pulsium 700 model to see what it’s like on the pothole strewn roads of the south-west, but before we do that let's take a look at some of the technology the French company’s engineers have included in the design.

The first thing you’ll notice about the Pulsium is the split top tube design just in front of the seat tube junction. There's a small rubber elastomer in the curved top tube that's intended to absorb vibration from the road surface.

The upper strut – the bit between the top tube and the seat post clamp – is designed to flex enough for the elastomer to compress by a maximum of 3.5mm, according to Lapierre, while acting like a brace to keep things stiff laterally. They say that flex between the two tubes is 27% greater than you get with their other endurance, the Sensium.

The curve from the top tube continues on through to the seatstays, acting like leaf spring suspension, according to Lapierre. The aim  is to take out the vibration before it travels up the seat post and through to the rider.

Lapierre have gone for a similar approach with the fork. They’ve created more of a curve in the legs by increasing the offset from 43mm to 50mm. The idea is to provide more shock absorption which should benefit your hands and wrists in the long run.

I’m interested to see what effect this has on handling, though, because increasing the offset reduces the trail (trail is the distance from the centre of the contact point of the front wheel with the ground to the intersection of the steering axis with the ground), and that can make things twitchy.

The lower half of the frame is all about transferring power using what Lapierre call Power Box technology. The front section of the top tube, tapered head tube, down tube, bottom bracket area and chainstays are all oversized. Lapierre say they’ve increased the length of the carbon fibres to maximise the amount of stiffness through these areas, so the Pulsium shouldn’t struggle to get the power down.

Races like the Tour of Flanders and Paris-Roubaix need big tyres to cope with the cobbles and the Pulsium will take widths up to 32mm thanks to a neat little bracket to adjust the height of the caliper at the rear brake bridge. Saying that, the Ultegra callipers will only take a maximum of 28mm so you'd  need to change those too.

The Pulsium comes in six sizes with top tube lengths ranging from 52cm up to 60cm. Each size gets its own carbon layup to optimise the power and comfort mix I’ve mentioned above, according to Lapierre. This includes the use of both 24T and 30T carbon fibres to get things just right.

The geometry is quite relaxed with our medium having a 165mm head tube length and a 545mm effective top tube. This’ll give a slightly more upright position than on a standard road bike, taking more of your bodyweight off the bars.

The Pulsium is ready for either electronic or mechanical shifting with the internal cables making for a clean look. Also, the cables are kept away from the tube walls to stop any rattling over rough surfaces; there's not much that's more irritating than a buzzing frame on a rough ride.  

The 700 model is the top build of three standard models and comes equipped with a full Shimano Ultegra Di2 electronic groupset with an internal seatpost battery. It’s the latest 11-speed version and comes with a decent spread of gears thanks to a 50/34T chainset and 11/32T cassette.

The components are pretty impressive too with Zipp supplying the handlebars and stem, and an Aliante saddle from Fizik.

Mavic provide the wheelset with their Ksyrium Equipe WTS and matching tyres – a bit of a budget offering for a three grand bike, but they’ve always shown themselves to be durable and quick rolling. 

Other models in the range are the 105-equipped 300 for £1,699.99 and the 500 which comes with mechanical Ultegra for £2,249.99.   

Right, the rain has stopped and the sun has come out so I’m off to find some cobbles. The review will be up soon so stay tuned to find out how this one performs. In the meantime, get more info from www.lapierre-bikes.co.uk.

With 20 years of road cycling and over 150,000 miles in his legs it's safe to say Stu is happiest when on the bike whatever the weather. Since writing his first review for road.cc back in 2009 he has also had a career in engineering including 3D-CAD design and product development, so has a real passion for all of the latest technology coming through in the industry but is also a sucker for a classic steel frame, skinny tyres, rim brakes and a damn good paintjob.
His fascination with gravel bikes is getting out of control too!

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