Cervelo ZFS-5 frame review – rad MTB racer from speed hungry roadies

Cervelo have finally officially released both 100 and 120mm versions of their ZFS-5 full-suspension race bike. Our freerange tech editor Guy Kesteven has been riding the frameset in both formats for several months though. So how does this roadie off-roader ride compared to his other flat out fast favorites and is it enough to put it top of the XC charts? 

Design and geometry

I’ve already gone into depth about the story behind the ZFS-5, the construction details and the truth behind first glance brand sibling similarities. But if you don't fancy clicking away, the short version is that Cervelo initially jumped into MTB to put bikes under new signings for Team Jumbo-Visma. For development speed and easy servicing it shares suspension hardware and kinematics with the Blur XC bike from Pon umbrella brand partners Santa Cruz. Reach is essentially the same as the Blur too but head angles are half a degree slacker at 66.6 degrees for the 120mm bike and 67.8 degrees for the 100mm bike. The composite lay up and tube shapes (including dramatically offset, squared base seat tube) are pure Cervelo too, using experience from the Aspero gravel race bike for the bottom bracket area and Jonas Vingegaard’s ultralight R5 road climbing bike for the mainframe. Together with headset routed cabling and lack of control cable/hose trunking, that saves over 200g over the Blur (1,729g  vs 1,932g) according to claimed weights for a medium with shock and hardware. You still get belly and chainstay protection, a threaded BB, replaceable UDH hanger and floating rear brake mount, plus a lifetime warranty too. Watching the speed other racers bikes eat their bearings and pivots this summer, the fact I’ve not even touched the Cervelo but it’s still silky smooth is a very good sign too.

Components and build

I received a bare frameset for test from Cervelo so I’ve run both 100 and 120mm travel formats and a bunch of different wheels, tires, fixed posts and droppers on it. The groupset is a power meter boosted version of the latest SRAM XX SL T-Type race Transmission with the latest Level Stealth Ultimate 4-pot brakes. It’s currently running the latest RockShox SID Ultimate fork and SIDLuxe Ultimate shock too, so it’s similar to the top 100mm build but with 120mm travel. Despite the heavy wireless Reverb AXS dropper and DT Swiss 350 rather than 180 hubs, it still sneaks under 11kg, but I’ve had it at almost 10kg with a rigid post and superlight Roval wheels and Specialized tires. 

Complete builds are below for reference, but for me the interesting thing is that Cervelo have gone for me the sensible Performance Elite spec on the Fox suspension rather than flagship Factory with its ‘has anyone ever actually noticed a performance difference’ Kashima gold coating. Despite the premium cachet of Cervelo, pricing is comparable to other boutique brands including Santa Cruz. I was shocked to see that the otherwise very similar in terms of weight, geometry and travel Specialized S-Works Epic Evo is £1000 more for the frameset and more expensive for comparable complete bikes too. Transposed against a Canyon Lux Trail CF 8 though the direct sell Deutchers are killing it on spec (if not on suspension performance). 

• ZFS-5 100 frameset (with Rockshox SID Luxe Ultimate shock): US TBC / £3,499
• ZFS-5 100 XX SL AXS (Rockshox SID SL Ultimate fork with Reserve 28XC wheels): $10,700 / £10,499
• ZFS-5 100 GX AXS (Rockshox SID SL Select+ fork with RaceFace ARC Offset 27 wheels): $6,250 / £6,599
• ZFS-5 100 GX Eagle (Rockshox SID SL Select+ fork with RaceFace ARC Offset 27 wheels): $5,000 / £5,399
• ZFS-5 120 frameset (with Fox Factory Float shock): US TBC / £3,499
• ZFS-5 120 XO AXS (Fox 34 Stepcast Performance Elite fork, Reserve 28 XC wheels, Rockshox Reverb AXS dropper): $8,700 / £8,499
• ZFS-5 120 GX AXS (Rockshox SID Select+ fork with RaceFace ARC Offset 27 wheels and RockShox Reverb dropper): $6,500 / £6,699
• ZFS-5 120 GX Eagle (Rockshox SID Select+ fork with RaceFace ARC Offset 27 wheels and Race Face fixed post): $5,250 / £5,499

Ride, handling and performance

It probably won’t surprise you that as a sub 11 kilo bike from a company with ridiculous racing palmares across road, track and tri, the ZFS-5 is basically extremely fast. At accelerating. At climbing. At punching out of corners. As a result it’s great for making people on heavier bikes cry whenever pedals are in play. Presuming you run suitable tires (I ran Maxxis Forekasters for a while just to explore how hard I could push the front end and they were noticeably slow), it turns miles into kms in terms of how quickly they go past too. 

The fact the rear end has been totally trouble free in the months I’ve been riding shouldn’t be a shock either, as the collet hardware is intrinsically durable and fully user serviceable when it starts to get gritty or loose. The smoothly flowing balance between power induced stiffness and relaxed pressure suppleness was a high point of the Blur when I tested it too. Cervelo not only added a telltale curve to the seatstay head though, they’ve also gone for a lighter ‘spring rate’ in the composite lay up compared to the Santa Cruz.

The last month or so I’ve been benefitting from the new ‘3P’ Open, Pedal, Lock remote controlled damper of the latest SID Ultimate fork and SIDLuxe Ultimate shock combo. That’s been a real specific situation control/efficiency booster on an already excellent suspension system, but don’t fret if your chosen spec only has a binary damper as open/closed works fine.

Switching from 100mm SID SL to 120mm SID Ultimate and old SIDLuxe 40mm stroke shock (for 100mm rear travel) to a new SIDLuxe with 45mm (for 115mm rear travel) the increase in slap happy chaos capability was very noticeable though. Stiffer, longer overlap forks with a grippier, bigger negative volume air spring meant I could properly stuff the front end into trouble without compromising speed or aggression. The faster high speed oil flow in the rear shock meant I didn’t end up with the rear wheel up around my ears or fixing punctures in XC tires as a result. This was neatly illustrated when I clocked a Strava PR down a brutally rocky, multiple drop, dry riverbed into rutted, twisting, yumping singletrack descent that’s been used for Enduro’s in the past. The time was a particularly surprising end of ride download win as the Cervelo had actually felt remarkably calm and steady on what’s normally a nervous tip toe on a lightweight trail bike let alone an XC rig.

It’s a tribute to Cervelo’s skill in taking weight out of composite frames without undermining accuracy and integrity that the ZFS-5 still feels hench enough to make full use of the relatively slack head tube and SID Ultimate / Forekaster tire pairing. There’s definitely some deflection and yaw when you’re pushing really hard, but it’s calm and communicative, rather than loading up and then letting go or starting to shake it’s head like a terrier with a rat. The more compact frame dimensions probably have a double part to play here. Structurally there’s less length and leverage to cope with between bars, pedals and rear axle. Mentally it’s mobile enough to let you know things are getting lairy in good time, rather than masking speed /impacts at arms length and then suddenly dropping the ball entirely. Super low weight also makes the ZFS-5 a lot easier to pop and hop around over stuff that might catch it out, or just to pump speed and fun out of flow trails.

As capable as it is for an XC bike, I was definitely living on my wits more on the Cervelo than 120/130mm trail bikes like the Yeti SB-120 or Santa Cruz Tallboy. So if you’re battering down black runs or smashing enduro tracks on a regular basis they’re worth the 2kg+ extra weight for reduced worrying. It’s way more than just a pure racer though and being able to cosplay different component choices over the past few months has underlined how versatile it is of your main focus is high velocity riding up and down the trails. 

Verdict

If you thought Cervelo’s full-suspension bike would be peakless, skin suit only roadie rubbish or a repainted Blur, then you’re in for a (very well tuned) shock. The ZFS-5 is superlight with a beautifully balanced frameset feel and pedaling/control suspension character for effortless climbing and race reaper / distance shrinker speed. Slack head angles are combined with compact reach to create an aggressive but agile ride that rewards dynamic riders brilliantly and can be pushed surprisingly hard in savage situations too. It won’t autopilot you out of every mistake though so it’s definitely still XC rather than DC at heart, even in the longer travel format. 

The simple to set up, proven durable, chaos capable suspension setup is balanced by weight saving cable routing that comes at the expense of easy servicing. It’s an acceptable price for lifetime warrantied exotica though and it’s sure to get people talking once they’ve got their breath back from failing to keep up.

Or to couch it in terms of my previous favorites, it's got all the best suspension and longevity traits of the Santa Cruz Blur but at a lower weight. It's got the same aggressive geometry and low weight as the Specialized Epic Evo but with less soggy suspension and for less money. It's got similar triple mode shock control to the Scott Spark too, but with a more aggressive head angle, better bearing longevity and a shock you can see and get to easily for quick setup. Hard not to give it a five then really, which wasn't what I was expecting when an aero road brand asked me to the launch of their first MTBs back in spring last year.

Test conditions

• Surface: Everything from Tarmac to deep slop
• Trails: Fireroad, local singletrack, moorland sheep track, rocky riverbed enduro courses, wild woods trails
• Conditions: Wet, warm, dry, cold, moistly meh

Tech specs: Cervelo ZFS-5 120 – current custom build

• Discipline: XCO/XCM/Trail
• Price: $TBC / £3,499 (frameset only)
• Head angle: 66.6 degrees
• Frame material: Cervelo carbon fiber
• Fork: RockShox SID Ultimate 120mm travel
• Shock: RockShox SIDLuxe 190 x 45mm 120mm travel
• Size: S, M, L (tested), XL
• Weight: 10.9kg
• Wheel size: 29in
• Chainset: SRAM XX SL Power 32T, 175mm chainset with Enduro Bearings X-15 bottom bracket. 
• Rear mech: SRAM XX SL AXS T-Type
• Shifter: SRAM XX SL AXS
• Cassette: SRAM XX SL T-Type 12-speed 10-52T
• Brakes: SRAM Level Stealth Ultimate 4 pot disc brakes with 180/160mm rotors. 
• Tires: Maxxis Rekon Race MaxTerra 3C EXO 29x2.25in front and rear
• Wheels: Reserve XC28 on DT Swiss 350 hubs
• Bars: Truvativ Atmos Carbon 760mm flat bar
• Grips: RockShox TwistLoc Ultimate
• Stem: Truvativ Atmos 7K 70mm 
• Seatpost: RockShox Reverb AXS 150mm dropper
• Saddle: Bontrager Verse Short Trail Elite