One of the bikes that I had significant (several hours) of saddle time on in Solvang was the 2013 Rumblefish Pro. The Pro is at the top of the Rumblefish line, with an MSRP of $4,299.
I had a Rumblefish several years ago, though there have been some changes in the intervening years. It still features pretty similar geometry (including the G2 fork). It still features the DRCV (dual rate control valve) shock, though it now also includes a DRCV fork.
DRCV is essentially 2 shocks in one. There are 2 separate air chambers in the shock (or fork). When the shock goes through about 40% of the total travel, a plunger inside the shock activates the second air chamber. I got to see a cutaway of the shock, and the technology is deceptively simple. What does it mean in real life? It means that travel feels endless. The shock doesn’t ramp up as you get to the end of the travel–the whole range of travel feels remarkably linear in force. You can use 100% of the available travel, without feeling harsh bottoming out. (I know. At the end of the ride, my o-rings were bottomed, but I never felt it.)
The Rumblefish has 120mm of travel, front and rear–close to 5 inches. 5 inches of travel coupled with 29″ wheels and DRCV makes the bike seem like the travel is endless. It has a 12×142 rear end, tapered headtube, Kashima coating on the suspension, aluminum frame and magnesium swingarm. The bottom bracket is press-fit (as I have on the Superfish).
Drivetrain is XT, shadow plus (Shimano’s anti-chain-slap version of the Type 2 SRAM technology) rear derailleur, 3×10. With 42/32/24 chainrings and 11-36 cassette, if you don’t have a gear for something you want to do, then there isn’t a gear that will make you happy.
The small gray switch visible just in front of/below the Shimano label on the rear derailleur activates and deactivates the Shadow Plus feature. Unlike SRAM, you cannot lock out the rear derailleur for ease of removing the rear wheel. There is a custom, very nice rubber guard on the chain stay.
The bike features XT brakes as well, and a RockShox Reverb adjustable seatpost with external cable routing.
The seatpost did feature barmount controls.
As should be expected, a mix of Bontrager parts make up the rest of the cockpit and touch points. I was riding with a pair of Crank Brothers Eggbeaters that I had brought with, and the bike I rod was equipped with Bontrager’s 29-3 tires, 2.3″ wide, on Team TLR wheels (tubeless ready, but they were set up with Tubes). I ran 25/28psi, front and rear.
The front and rear DRCV suspension bits were Fox’s CTD (climb/trail/descend) technology.
Let’s start with the CTD, because I think it’s one of the best improvements on the bike. As the name implies, CTD has 3 positions. On the fork, flip the switch forward for descend–in descend, you get the loosest valving and most use of the suspension travel. On the shock, flip the switch to the left (towards the front brake) for descend. Middle position is trail–kind of a standard valving. On the fork, flip the switch back for climb–that’s basically lockout, with a pretty high-threshold blowoff. The shock is to the right (towards the rear brake) for climb. If that sounds complicated, you get used to it quickly. Going up? Your weight shifts to the rear, and you flip the controls to the rear. Going down? Opposite. Can’t remember? Go to the middle, and you’ll be ok.
I had a chance to ride with Gary Fisher, and I was amazed by how often he was adjusting the suspension, cycling between the different settings.
That’s me on the Rumblefish, chasing Gary on a Superfly 100.
When I had a Rumblefish, one of my biggest complaints was in the realm of climbing. When you were doing a hard, out of the saddle effort, the rear suspension would get a severe, pedal-induced bob. Once that started, the rear suspension/tire would load up and unload, causing the tire to grip/slip/grip/slip. That was a surefire way to lose traction and be forced to stop. Maybe it’s my poor pedaling technique when trying to muscle up a hill, but it was decidely prominent in the bike’s handling. CTD ends that problem. When you’re approaching a hard climb, flip the suspension to Climb (or just flip the shock, if you want). It will then climb like a hardtail, without any drama. There will be a very small amount of suspension compliance, but there will be no bobbing present. The CTD technology is exactly what the rear of this bike needed. Of note, I do not have the same hopping issue with the rear suspension on my Superfish (albeit with 80mm of rear travel).
In the trail setting, the bike handles very well in most conditions, and the DRCV gives you maximum use of the available travel.
In the descend setting, the bike transforms yet again–into a big travel, big-hit, all-mountain bike. I was amazed by how plush the suspension was in descend. It would rail corners and hop obstacles on the Super-D course like a completely different bike. It was a very dramatic change in handling. Of note–the much more ‘plush’ ride does bring slightly different ride characteristics. The first time I grabbed a handful of front brake in the descend setting, the nose bobbed pretty seriously, and I thought I was setting myself up to endo. Backing off of the brakes cured that issue. The more I rode it, the more I found that I could use the brakes to my advantage, loading up the suspension before an obstacle to give me a bit of extra hop to get over, or loading up the front before railing a berm. CTD flatly works, and works well.
The fork is a Fox 32. At my svelte weight, I didn’t have any problems with fork rigidity, and think that going to a 34 would really be overkill.
The bike also features Trek’s Active Brake Pivot (ABP), which I’ve written about previously. In my opinion, ABP works pretty remarkably well in keeping the action of the rear brake and rear suspension independent of each other. There is no palpable rear brake jack with the suspension. I’m an ABP believer.
One thing I have a hard time with is the 3×10 drivetrain. I’ll talk about Shimano vs. SRAM another day, but I can see absolutely no purpose to equipping a bike with 3×10. You can get the same ratio spread with 2×10, with a lighter, simpler drivetrain. Frankly, I found the gaps between the triple chainrings to be too small–if I wanted to shift chainrings, I wanted a bigger jump than 1-2 or 2-3 provided. Once I got used to it, I spent my time in the middle (32) chainring, and just shifted the cassette. I understand that some riders perceive a value in 3×10, and I’m sure Trek specs it in this way to meet that demand. Notwithstanding what those riders think they want, I bet they’d be happier with 2×10, once they rode it. (Does anyone really need 24/36 or 44/11 gearing on a Rumblefish?) When I had a Rumblefish with a triple, I pulled the big chainring and ran a BBG bashguard. Even on road rides, I never ran out of gearing.
So the strengths of the bike are great handling, great suspension, great components (XT brakes performed flawlessly, as did the drivetrain), and some great ideas (e.g. DRCV). One weakness is identified above: 3×10 drivetrain.
A second weakness is weight. Granted, I was running some relatively aggressive 2.3″ tires, tubed. A tubeless conversion is possible with the stock wheels, and would help a lot. I ran Easton Havens on my Rumblefish along with Maxxis Ikons, and they made a huge difference in perceived weight, particularly when climbing. I didn’t get a chance to actually weigh the Rumblefish, but based on what I’ve read, they weigh in around 29-30 pounds. 30 pounds isn’t bad for an aluminum 29er with 5 inches of travel. But the bike feels heavier than 30 pounds. It is by no means fair comparing the stock Rumblefish to my ENVE clad Superfish–totally different realms, obviously. But the Rumblefish felt heavy when climbing. On the flats and descents, it felt great–and I really appreciated the grip of the 29-3 Bontrager tires when trying to keep up with Gary in the corners. But on climbs, it felt ponderous. Even with the suspension locked out and enough gearing to scale Everest, the bike felt heavier than it should have.
Based on my past experience with a Rumblefish of my own, I know that much of that perceived weight comes from the wheels and tires. Going tubeless on the stock wheels, or upgrading to lighter wheels and tires should be an upgrade at the top of any Rumblefish rider’s list. I understand why Trek sells them with tubes–it’s undoubtedly hard to keep tubeless tired bikes ‘happy’ sitting in boxes or on shelves. But the tubed setup with moderately heavy tires makes this bike feel slower than it really is. And I know that the bike feels much more sprightly with more athletic shoes.
That’s it. Those are the only complaints. The Rockshox dropper post worked admirably, and I really liked having it. I used it quite a bit. The two weaknesses that I’m whining about are pretty simple. Relative to the 3×10 drivetrain, you can either drop a chainring and add a bashguard, as I did on my Rumblefish, or you can convert to an alternative drivetrain. Relative to weight, you can do a lot to address perceived weight with some simple solutions relating to the tires (ranging from just going tubeless up to going with different hoops altogether).
The Rumblefish is a 5″ travel all mountain 29er trail bike that feels at home in a wide array of conditions. The component spec is well-thought out (save for 3×10), and functions admirably. The geometry is spot-on. The addition of CTD to the bike really changed its character–you get 3 bikes in one: a rigid 29er with a huge gear range for climbing, an trail 29er with progressive travel for ‘heavy XC’ or all mountain use, and a bottomless travel trail-ripper for shredding the downhill.