That’s right, you can now have a 190mm travel single-crown 29er fork
RockShox ZEB is the the new big-hitting single-crown fork with 38mm upper tubes. Travel options are 160-190mm in both 27.5in and 29in.
RockShox ZEB need to know
- Ultimate, Select and Zeb options available aftermarket, with prices starting at £679. Select+ is OE only
- Latest DebonAir spring equalizes at full extension, and gets an updated top-out bumper
- Dual Position air option is available for e-bikes
- Ultimate level fork get the same Charger RC2 damper cartridge developed for Lyrik
- Fork offset options are 38mm (27.5in), 44mm (27.5in and 29in)
- Uncut weight for the 170mm 29er Zeb is 2.28kg, so only 210g heavier than the equivalent travel Lyrik
Bigger is better, right? Well, in the land of the brave that certainly seems to be the case – monster trucks, seven-lane highways, super-sized meals and obesity all exports from the USA. And it’s not just waistlines that are expanding, forks are getting bigger too and it’s the American brands that are making the headlines. First Fox released the Fox Float 38 to fill the gap between the 36 and and 40, now RockShox follows suit with the new Zeb, also rocking 38mm upper tubes (although we’ve since learned that RST Suspension launched a 38mm stanchion single-crown fork – the Stitch – last summer).
And while it’s easy to assume that it’s the ever increasing demands of enduro racing that’s instigated this progression, the real driving force here is e-bikes. One look at the Cannondale Moterra SE and Specialized Turbo Kenevo Expert, both with dual-crown Boxxer forks, gives you a good insight into the demands placed on longer travel e-bikes. With associated increases in weight, speed and ride time, everything about e-bikes is supersized, so it’s fitting that the forks get bigger too.
And while e-bikes are relatively new, oversized single-crown forks are not. If you lived through the freeride era with helter-skelter skinnies and hucks to flat, you’ll no doubt remember the RockShox Totem with its 40mm upper tubes and a 1.5in straight steerer option.
In recent years, the fork pendulum has swung more towards weight saving and enduro racing, settling now on a happy medium, the new Zeb fork weighing 2.28kg in the 170mm travel 29er option. That’s just 210g heavier than the equivalent travel RockShox Lyrik and for those keeping score, the Zeb is also 70g lighter than the new Fox 38.
There’s not much of a weight penalty for going bigger, so what advantages does the 38mm fork chassis bring? According to RockShox the Zeb is 21.5% stiffer torsionally, 7% stiffer in side-bending and 2% stiffer in fore/aft than the equivalent Lyrik. The gains are mostly torsional then, so there’s a big reduction in independent leg movement, which in turn gives better tracking and steering precision. It’s also why RockShox has been able to stick with the lighter 110x15mm axle rather than adoptimng the 20mm standard found on the Boxxer. Being a RockShox fork, the dropouts are Torque Cap compatible, which gives you an additional degree for tunability over stiffness.
And while it’s by far the beefiest fork in the RockShox range, Zeb also takes some design cues from the lightest fork in the line, the RockShox SID. With its sculpted angular arch the magnesium lower leg assembly offers clearance for 2.8in tyres. The arch also juts forward more to guarantee better clearance at bottom out with beefed up head tubes. Anyone for a 1.8in tapered steerer tube? Well, it’s on its way, at least for e-bikes, anyway. The updated design also better accommodates fenders and RockShox even has its own. Yes, it’s probably too short for the worst UK conditions, but at least the mounts are in place for other bands to capitalize on them.
And the Zeb isn’t just broader, it’s also taller. RockShox claims it’s 5mm taller than Lyrik, but we measured it axle to crown height on the 170mm travel 29in Zeb at 590mm which is 8mm higher than the Lyrik and enough to slacken the head angle on our Specialized Enduro S-Works 29 test rig by almost 0.5º.
Those are the obvious external features, now let’s take a look under the hood of the new Zeb. In the damper side, the Zeb Ultimate gets a Charger 2.1 RC2 cartridge straight out of the Lyrik Ultimate with a modified top cap to fit the 38mm uppers. So you have high and low speed compression and low-speed rebound adjustment at your fingertips. As you go down the range the damping level on Zeb mirrors Lyrik through Select+ and Select options.
It’s the air spring, or more specifically the operating pressures that see a departure from Lyrik. Yes, it still sports the latest Debonair design, albeit with a modified top-out bumper, but due to the increased tube diameter, and subsequently the seal head, the Zeb runs much lower pressures than a Lyrik. I typically run 70psi in the 170mm 29er Lyrik but on the Zeb I’m down at 47.5psi. Also small changes in spring pressure make a big difference, where a 1psi change can be felt in the ride height of the fork. As such, a digital shock pump, or at the very least a low pressure analog one, is a must. There’s also a Dual Position Air option on the entry level Zeb that enables you to reduce travel by 30mm to improve climbing on e-bikes. It adds £100 to the bottom line and given that climbing is already easier on e-bikes thanks to the motor, it will be interesting to see if it turns out to be useful or just a recycled fad from regular mtbs.
The drop in spring pressure is inline with the increased area of the air piston head, but seal overlap has gone up, even if not to the same degree. As such the Zeb takes longer to bed in than a Lyrik.
I’ve already had three long rides on the Zeb and it’s not as fluid in motion as the Lyrik. With each successive ride it’s freed up and even though it has not matched the sensitivity of the Lyrik just yet, we can already feel areas where the Zeb brings advantages. On a bike like the Specialized Enduro 29 which is essentially a DH bike that can be ridden up mountains, the Zeb offers a new level of confidence. Dive into a step rough corner and the fork remains steadfast. On big hits it doesn’t falter either, and with the more linear air spring it’s proving easier to access more of the travel too, without compromising support.
he next step for me it to get it on an e-bike to accelerate the bedding in period. And once up to speed it will be going head to head with the Fox 38.