Trek’s big wheeled Rumblefish is not just a mile muncher

What does mbr really think about 29er bikes? Simple — there are good bikes and bad bikes. Find out how the Trek Rumblefish shapes up. Photos by Roo Fowler

This year sees the rear travel on the Rumblefish increase by 10mm to match the 120mm travel fork. And with Trek’s DRCV suspension technology front and rear, it’s easily Trek’s most capable 29er to date.

The 2012 Trek Rumblefish Elite

Frame

Combining key features developed on Trek’s 26in bikes — E2 tapered head tube, ABP suspension and oversized alloy pivot hardware — with the increased acceptability of bolt-through dropouts front and rear, the Rumblefish chassis offers unprecedented stiffness for a 29er.

In the features frenzy on the Trek website — we counted 16 in total — it seems to have overlooked one of our favourite ideas: bump-stops integrated into the chainstay protector, where the forward one should prevent the chain getting caught up in the rear tyre. Another neat idea is the two rotating line guides for running a dropper post remote cable either side of the top tube.

DRCV shock provides a more linear spring curve

Suspension

The ABP rear suspension design on the Rumblefish is very similar to the Trek Fuel EX, but instead of having the shock running parallel to the seat tube, it is tucked under the top tube. This puts the ProPedal lever on the Fox RP2 shock within easy reach — not that it matters, as the Rumblefish pedals perfectly well with the shock open.

Up front, the 120mm DRCV Fox Float RL does what it says on the tin and combined with the QR15 lowers, it gives the Rumblefish an edge over the Camber.

Wheels

Plagued by pinch flats on the rock-strewn trails of Afan, we were about ready to chuck the Rumblefish into the trees. We’ve had a similar experience on other Bontrager rims, and attribute it to the sharp, square profile of the rim edge. We were running thinner tyres than stock, but the following week the rear wheel pretty much collapsed on the not-so-rugged trails of the Surrey Hills.

Brakes

We love the raw stopping power and reliability of the Shimano SLX brakes. But the Servo Wave design also produces dead lever travel and some resistance at the start of the stroke. Ultimately, the SLX brakes don’t offer the same sensitivity and modulation as the Avids.

Components

With a 690mm riser and rangy 105mm stem the steering response and balance of the 19in Rumblefish felt a little odd. After some experimenting we settled for a 60mm stem and 750mm bar.

Big wheels can jump

Performance

With the cockpit sorted and balance restored, the Rumblefish revealed the beating heart of a trail demon. This bike simply rockets up climbs, without having to sit on the nose of the saddle or crouch down to get your weight over the front wheel. The bigger wheels deflect less off rocks and help smooth out the trail. Comfortable? You bet. Better ride quality than the Fuel EX? Yes. Boring? Hardly.

On the descents, the Rumblefish begs you to go as hard as you dare, but the sweet sound of the breeze is too often accompanied by the hiss of a pinch flat.

The tauter suspension doesn’t offer as plush a ride as the Camber, but the Rumblefish pumps better and rides flatter for it. On our steepest test track, the Rumblefish set marginally faster times than the Camber, no doubt aided by the extra 10mm of travel and longer wheelbase, only to lose out on flatter flowing trails. One downside of the increased stability: the suspension can’t be preloaded as easily to help get the bike off the ground, or when throwing your weight back. Obviously, there are pros and cons to both set-ups.

>>> Click here to find out more about geometry with our handy guide

Verdict

Contrary to how most 29ers are marketed, it is the steep, nasty, rooty descents where the Trek Rumblefish Elite really excels. It’s no slouch on the ups either, despite its big bones.

The solid chassis and good geometry make for a confidence-inspiring ride and the balanced, controlled suspension response aids the sense of security.

And while Trek should be commended for investing in state-of-the-art suspension technology, the Rumblefish also needs the components and wheel strength to back it up, especially given that the Specialized Camber is well dialled straight out of the box.

Rating: 8