As previously mentioned, the Altitude will replace the ETS-X. Design highlights of the Altitude include; SMOOTHLINK™ suspension; STRAIGHT UP™ geometry, swooping top tubes on the front end for low centre-of-gravity and increased standover, swooping down tubes for shock piggy back and water bottle clearance, 7005 aluminium frames utilizing RMB’s FORM™ design and on higher-end lighter framesets – C12 carbon monocoque frames (rocker links, front end main frame and seat stays).
I’ll expand more on these above concepts further in the review. Note that the carbon frame is outside the scope of this review so that is all I will mention in this matter. Please check the RMB site for more information on the RSL (Racing Super Light) carbon framed Altitude 70 and 90
As expected, the Altitude’s welds are clean. The paintjob on my prototype bike is a nice eggshell white that seems to shed mud very well. The production bike colours will be more of a bright white colour as depicted in the pictures at the end of this review. The aluminium tubes are designed in a process that RMB calls FORM™. All tubing on the Altitude is custom-made, drawn from 7005 alloy then cold-worked. Every tube is fully butted.
The Altitude incorporates a large hollow head tube area in an effort to increase stiffness. Also of note is the incorporation of aerodynamic leading edges – not to decrease wind resistance but to aid in deflecting rocks. Unfortunately in many of these pictures I put a mud splash guard on the down-tube to help forestall rock damage.
Front End – noting the large head tube and the elliptical leading edge of the down tube with stylish zip-tied mud guard
The Altitude’s seat tube is butted and hydroformed. Note in the pictures below that the centre section of the tube is bulged. By bulging the centre section, RMB eliminated the need to weld on a rocker mount, opting instead for a stronger piercing for the oversized rocker link pivots. The rectangular bias in the seat tube is an effort to also increase stiffness.
Rear linkage – non-drive side
Rear linkage – drive side
Rear drive-side – note the assymetric chain stays
The swooping bends in the seat tube and down-tube are apparently not motivated purely by fashion. According to RMB, the down tube shape was necessary in order to keep the shock (and centre-of-gravity) as low as possible in the frame, and also in order to create enough room for a water bottle in all frame sizes. The down tube shape also allows the rider to run a shock with a reservoir.
Since the Altitude frameset is so well thought-out it was with some relief that I felt I could do my “job” as a reviewer and point out some possible negatives. The water bottle placement mounts do not allow a shock with a piggyback reservoir to be run as the reservoir would impact the water bottle. I am told that RMB will be correcting this in production frames.
Water bottle mount placements will be moved forward in production frames
Under certain circumstances, when approaching technical obstacles (the up and over log-pile in the picture below being a perfect example), the downtube kink on the frame could potentially impact the obstacle well before the large chainring hits the obstacle. This won’t be a huge problem with something nice and soft like a log but could be a tad more damaging if the obstacle is a rock ramp or ledge. Of note, the carbon frame’s downtube will not have such a pronounced kink so RMB is aware of the possibility of damage. This isn’t so much a flaw in the design but a note to the rider to be conscious of using technique when going up and over obstacles at the risk of some inadvertent downtube contact and/or damage.
Curved downtube may impact objects – rider beware! Carbon frame’s downtube will be less radically kinked
RMB designed a pocket in the rear of the seat tube to allow for tire clearance at full rear shock compression, giving the frame set a full 10mm of clearance with a 2.3” WTB from the seat tube. There is also that much clearance in the chain stays with the same tire. I am told (but did not independently verify this claim) that a 2.5″ WTB would fit. Numbers are all very fine. The true test was on my Chilcotin trip when I encountered some very muddy trails. I can state with some relief that there is plenty of clearance with a 2.3″ WTB tire even with the presence of copious amounts of mud. I further note that production frames will have even more tire clearance then the prototype frame as depicted in the picture below.
Deceptive amount of rear tire clearance
This tire ran just fine despite a lot of mud on the frame