The Tour of Flanders is raced this weekend which will see the best cyclists in the world tackle some of the most brutal ascents they will face in the season. 

The Flandrian climbs may not be as long as the Alpe d'Huez or as trecherous as the Stelvio, but what they lack in length and accumulated height they gain in severity. 

The climbs on the Tour of Flanders and indeed in all of the spring classics in Northern Europe are normally between .4km and 2.5km in length with varying degreees of difficulty; both in terms of average or maximum gradient but also with the road surface, with many of the climbs being on narrow, cobbled roads. 

Here we take you through our top 5 Flandrian climbs in celebration of the Tour of Flanders:

Koppenberg

Length: 0.7km 

Avg Gradient: 11.6%

Max Gradient: 22%

The Koppenberg is truly an icon of not only the Tour of Flanders, but cycling in the entire Ardennes area. The climb is covered entirely with uneven cobbles and is narrow enough to only allow 4 or 5 riders to ride abreast of each other. 

Not that they do, with the severe 22% max gradient ensuring the climb is tackled in near enough single file with riders often taking to the very edge where the cobbles are more worn and the effects felt less.

The Koppenberg featured every year from 1976 to 1987 when Danish rider Jesper Skibby was accidentally run over by the commissaire's car as the driver tried to get out from behind him on the climb. After refurbishments to widen and re-pave it, the climb was included again in 2002 but was withdrawnb yet again in 2007 due to deteriorating conditions. 

It featured the year after though and since 2008 has been a key addition to the race. 

Paterberg

Length: 0.4km

Avg Gradient: 12.5%

Max Gradient: 20%

The Paterberg is another fabled climb that came about in 1986 when a local farmer wanted the race to come nearer his house, so he paved the hill with cobbles.

A very short climb at only 400m may make it seem like it should be simple for professional cyclists, but the maximum gradient of 20% goes on for 100m of the climb which make it extremely difficult especially in race conditions. Usually the Paterberg is a key point in the race and is frequently used as a launch point for key attacks.

The crowds at the Paterberg are always large which make them hectic and noisy, adding to the difficulty the rider face whilst trying to race up them. The climb often features in the race more than once, with the final climb usually being one of the last which makes for a great spectacle after more than 250km of racing.

Oude Kwaremont

Length: 2.2km

Avg Gradient: 4.2%

Max Gradient: 11%

The Kwaremont doesn't have the leg-breaking gradients of the Paterberg or Koppenberg, but the technical nature of the climb along with some steep gradients up the ascent make it a crucial part of a race.

The first 600m of the Kwaremoent are on a narrow lane which will make the fight for position beforehand crucial as being caught out at the back of the peloton could cost you vital seconds or even minutes if a bottleneck occurs, should there be a crash or a rider suffer a mechanical. 

The next 1600m are cobblestones and include the most difficult gradients on the climb, with the surface being uneven and difficult to negotiate for even the best bike handlers.

Although the gradient evens out considerably towards the top the cobbles still make it a tough climb and as it often features more than once in a race, one that is guaranteed to sap energy and be a flash point for attacks from strong riders.

Taaienberg

Length: 0.8km

Avg Gradient: 7.2%

Max Gradient: 18%

The Taaienberg is a climb that may not be the steepest, or longest, but iften has stretegic importance in the races around the region due to it's location on the course. 

Sometimes the Taaienberg is one of the first climbs of the day which make it a great place for a breakaway to go and the first attacks to come; but in recent years it has enjoyed a place near to the end of the races where it can be used as a launch for a decisive attack or to thin out the select group to contest the finish. 

The Taaienberg rarely features alone, often being part of a threesome of climbs in a key point in the race which makes for an excellent spectacle and for attracting large crowds.

Kruisberg

Length: 1km

Avg Gradient: 6%

Max Gradient: 9.8%

The Kruisberg has been part of the Flandrian races since 1973 and since 2012 hasenjoyed status as a fixed climb in the Tour of Flanders race.

Whilst not the most difficult race of itself, the Kruisberg's p[osition at the end of the Tour of Flanders makes it an important strategic point in the race as it comes before the Kwaremont and Paterberg as part of the final trio; often being the climb where initial attacks from riders hoping to win the race start to happen. 

Of the 1000m of climbing there are 450m of cobbles, although the gradients are relatively gentle compared to other climbs in the race but after 250km of racing up and down these climbs, the Kruisberg can often be the place where riders finally crack and drop out of the peloton or group of favourites.