BMC Fourstroke FS01 29 – the BIke introduced: by c_g

Like announced recently here, we were in Switzerland for the weekend with the prime objective to attend the presentation of the new BMC 29″ers. As you may remember the BMC big wheeled bikes are not new to us at twentynineinches.com – we had the 2012 model Speedfox SF29 (full suspension) and Teamelite TE29 (hardtail) on test. BMC had already presented the carbon version of Teamelite, the TE01 this spring (Grannygear reported at the time and now I also have had a day of riding on it – a report may follow) … now – as already suspected by some :) – the carbon version of the full-suspension bike is coming and it is coming under the name Fourstroke FS01 29.

BMC has invited us to Lenzerheide in Switzerland for the World Press Launch at the summit of the Papaner Rothorn and let us try the bikes on the brilliant trails of this region. While the 29″er Speedfox was designed as mid-range full suspension bike, with their new Fourstroke FS0129 BMC went straight for the top.

A bike that wants to break the boundaries of categorization – a bike that in terms of efficiency, speed and weight can compete with the best XC race fullies but at the same time is said to provide such a level of control and comfort, that one could put it in the same league with the best 29″er trail bikes. „Lofty goals“, you may say – and we think so, too, but since I got to ride the bike I had an chance to build my opinion first hand. The next post, in a few days, will cover my riding impressions and will tell whether and how the BMC has succeeded (or failed) with their goal.

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You could call the Fourstroke FS01 29 the next generation Speedfox 29 – it shares the same geometry, 100 mm of travel front and rear, the BMC typical APS-suspension system (“Advanced Pivot System”), a very similar design and a number of details that have been carried over , … but then there are the state-of-the-art full carbon frame, the updated damper technology and last but not least the numerous improvements on details.

So here without further adieu – directly to the technologies that make up the FS01 Fourstroke 29″er.

The full carbon frame of the Fourstroke FS01 29 is not only super light (we were quoted 2040 g for size Med – with shock and hardware), but also very stiff (the shown comparison values indicate significantly higher stiffness, as the already impressive stiff Fourstroke 26″er – and .. that with with almost the same frame weight!!).

Of course, the Fourstroke FS01 29ers received all the modern technologies such as BB90 PressFit bottom bracket (No. 2 in the graphic), 142/12 Rear axle, tapered head tube (No. 5), and much more, but the secret of the low weight (at maximum rigidity) is the application of the latest in carbon technology and layup.

And the frame has more clever details to show:

• The cable routing of the Fourstroke FS01 29 runs mostly externally (No.1) only in the short section in the right chain stay the rear derailleur cable runs internally. As an added bonus the BMC Fourstroke FS01 29 has an extra inlet at the bottom bracket, taking a remote cable for either a Reverb Stealth seat post or a remote lockout for the shock. The opening for the remote on the shock (should you choose to go this way) is well protected behind the shock on the seat tube.

•Next is BMC´s “Chain Management System” (the lower No. 3 ;) ) which consists of an integrated chain guide mount for the BMC chain guides that come with the frame.The guides provided work with dual or triple. Another part of the system is the carbon frame saver plate just above the bottom bracket. It prevents the chain from jumping off the small chain ring and damaging the frame. The plate can be fine tuned for different chain lines by various spacers.

•The post mount brake pods (No. 6, BMC speaks of “Natural Born Post Mount”)have aluminum thread inserts that are easy to replace if damaged. Good thinking.
• Another positive feature is the Sag Indicator on the rocker, telling you whether you are running the bike within the recommended sag.

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BMC has entered the 29″er game relatively late (in late´11) – but they have definitely thought about how they would want their 29″er to ride and from these considerations, the BWC (“Big Wheel Concept”) has been born. It is based on the following key factors:

•long main triangle, combined with a short stem (80 mm) and a wide bar (700-720mm)
•moderate steering angle
•moderate bottom bracket drop
•compact rear triangle with a chain stay length of only 445 mm
•low stack … meaning a low front via a short head tube and semi integrated headsets

THE APS SYSTEM:No suspension system in itself is better than another – but none are as versatile to tune without compromising in a few parameters as a virtual pivot system … when done right.

That is the unanimous opinion of the designers and engineers at BMC and this is also the reason why all BMC full suspension platforms (currently 100 to 150 mm) are based on it. The two frame units units (the main frame and swing arm) are all in one piece and connected by very precise bearings and short links – all in order to generate the best possible lateral ad torsional rigidity.

In the test of the Speedfox SF29 earlier this year, the combination of the Fox RP2 rear shock and the APS system were not a perfect match – primarily because of the lack in adjustability on the shock´s platform damping. Now with the FOX CTD BV shock mounted, it may well be that the rear finally can play to its full strength. For this purpose BMC had specialists from FOX come for this event to set up the bikes perfectly to our us and give us a introduction to the CTD settings.

We will report shortly on how the character of the bike has changed as a result.

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Besides the top version (as tested) there are two more models planned – one with a carbon main frame and aluminum swing arm (FS02 29, bottom in size S) and a all alloy version (FS03 29, on top, in size M), which is to replace the current Speedfox SF29. The components have not yet been finalized, but will be according to the targeted price range.

All Fourstroke 29″er models (possibly even in other colors) are said to become available shortly after the Eurobike’12.

So much for the intro of the brand new BMC Fourstroke FS01 29″ers. Once I manage to wipe that wide grin off my face (that I keep having since I hit the brilliant trails around Davos and Lenzerheide ) I will put down my thoughts of the riding impressions on the Fourstroke FS01 29″ers in a post and bring them to you.

Until then … RIDE ON
c_g