What do you call a bike in which you can ride two different wheel sizes? Well, some call it a convertible bike, others simply give the bike in question its own model name depending on the current wheel configuration. The Canadians around Rocky Mountain are taking the second route and thus expanding their model range. The model is called Instinct when it is fitted with 29er wheels. However, if it rolls on wide 27.5x2.8 tyres, the whole thing is called Pipeline. Apart from the wheels, tyres and, interestingly, the brakes, both models are completely identical and therefore both cost exactly 5800 euros.
As 29-inch tyres in 2.3-inch width and 27.5-inch tyres in 2.8-inch width are not exactly the same in diameter, it makes sense to equalise the bottom bracket height. The radius between the two wheels is 12 millimetres. As the Instinct already has a fairly low bottom bracket despite the 29er wheels, the Pipeline has to be raised somehow. Some manufacturers solve the problem with a flip chip, but Rocky Mountain uses a simple 12-millimetre spacer that is pressed into the bottom of the head tube. However, this measure is not quite enough to raise the Pipeline to the same level. Even unloaded, the Pipeline is still four millimetres lower, plus the lower tyre pressure causes it to sink in more. However, the so-called Ride 9 adjustment on the rear shock mount allows the spring characteristic and geometry, including the bottom bracket height, to be adjusted. To prevent unwanted pedal bob, we never rode the Pipeline in the lowest and flattest position.
A look at the data sheet reveals many similarities but also clear differences. Both Rocky brothers have a smooth geometry with a slack steering angle, paired with a first-class rear end. Despite its high sensitivity, the rear end is very stable and smooth when pedalling, even with the shock open. The riding position and handling are also impressive right from the start. Sit on it and feel good. However, due to the rather long chainstays, effort is required when lifting the front wheel.
The fundamentally different dispositions come to light within the first few metres on the trail. The chubbier Pipeline weighs around 600 grams more. The entire weight difference is due to the wheels and tyres. In addition, the Pipeline not only has significantly wider tyres, but also coarser tyres with a grippier but also poorer rolling rubber compound. Every short sprint and crisp climb makes this difference noticeable. The Instinct simply hangs on to the throttle better and feels more lively on the descents. In the
Compared to the normal 29er tyres, the plus tyres in the Pipeline are content with just 1 to 1.3 bar. This provides an extra portion of comfort and generates more grip. Thanks to the very wide rims with an inner width of 35 mm, the tyres are also very stable and hardly buckle even under high lateral loads. Even in muddy conditions, the 29er combination of Maxxis Minion DHR and the low-profile Forekaster couldn't keep up with the wide tyres. Depending on the position of the Ride 9 adjustment (see detail above), the rear suspension travel also changes. In the slackest geometry, the travel is the shortest, and in the steepest geometry, 21 millimetres more is available. In general, both rear triangles feel very potent. In combination with the Plus tyres, however, this impression is further enhanced.
Peter Nilges, BIKE Test Manager:
With Pipeline and Instinct, Rocky impressively demonstrates just how much the character of a bike changes depending on the tyre size. Both work perfectly, but have different strengths. The 29er is significantly more climbing-friendly and lively, while the Pipeline can go one better on the descents. According to the points system, the Instinct wins by a narrow margin.
ROCKY MOUNTAIN INSTINT CARBON 7 29"
Price (frame) 5800 Euro
Weight 12.4 kg
Web www.bikeaction.de
Thanks to its significantly lighter 29er wheels, the Instinct is the sportier and generally more balanced all-mountain bike. With better propulsion and better climbing characteristics, it saves more energy on extended tours. Sporty riders are guaranteed to be happier with this setup. However, it should not be underestimated on the downhill either, especially as the somewhat tame tyres still offer potential here.
ROCKY MOUNTAIN PIPELINE CARBON 70 27.5"
Price (frame) 5800 Euro
Weight 12.9 kg
Web www.bikeaction.de
With its 2.8 plus tyres, the Pipeline weighs 560 grams more. Apart from the brakes, however, it is otherwise identical to the Instinct. Thanks to the wide tyres, the Pipeline's range of use shifts towards downhill, which is why the bike scratches the enduro category. More grip and more comfort are offset by more sluggish handling and higher rolling resistance.
You can read this article or the entire BIKE 3/2018 issue in the BIKE app (iTunes and Google Play) or buy the issue in the DK shop reorder:
