Felt Z1, Part II

The Z’s bottom bracket is massive. To be any broader Felt would need to move to BB30.

When I found out that the Z1 frame was tipping the scales at 900g, I knew I wanted to review one. My first trip out on one came in borrowing one belonging to one of Felt’s staffers. In two rides I knew I needed to experience more.

I arranged for a frameset rather than complete bike. I had a Campy group sort of lying around waiting to go on a bike. Doing reviews this way cuts the expense for a bike company pretty radically and while I had done this on a number of occasions previously, that’s not quite what I did here. Spoiler alert: I bought the frameset.

With that out of the way, here’s why: When it comes to my views on frame geometry, high performance carbon fiber construction and weight, the Z1 comes very close to everything I want in a bike. Traditionally, my preferences have been for relatively low weight, a longish wheelbase, a tad more trail and good torsional stiffness. I also like a low bottom bracket, but as far as production frames go, that’s just a pipe dream on my part thanks to the CPSC. The Z, like all Felt road frames, has a 27cm-high BB.

As I see it, you have several alternatives. You can buy a heavier frame that will offer more impact/crash resistance. It may handle better, or it may not. It may have a superior road feel, or it may not. You can buy a frame with a lower BB, but it won’t be as light. Of course, you can choose to purchase a frame with a shorter wheelbase and less trail and those bikes abound.

That tiny carbon fiber “patch” (not their term) is where the chainstay is co-molded to the bottom bracket, yielding a strong joint that is much lighter than what would result with a traditional lug.

My preferences aside, in absolute terms, the Felt Z1 is a remarkable and rare bicycle. To my knowledge, it is the only grand touring frame that tips the scale at less than 1kg in a 56cm frame. Even the Cervelo RS weighs more than 1kg. And while weight isn’t everything, the bike’s weight comes with an important corollary. To be that light, the frame must employ a fairly ambitious blend of intermediate, high, and ultra-high modulus carbon fiber. This blend allows for exceptionally thin-walled tubes. As a result, the Z1 has a road feel that imparts much greater sensitivity than competitive models. As much as I like the Roubaix, the Z1 has a far superior road feel.

Among cycling cognoscenti there’s a certain mistrust of bike reviews. The joke goes, “and they said it was torsionally stiff and vertically compliant.” I think the reason these assessments don’t pass the BS meter is simple. Anyone who rode steel from the Columbus SL/Reynolds 531 era knows a thing or two about vertical compliance. And if you ever rode one of the bonded aluminum Alan or Guerciotti frames, then you know a lot about vertical compliance. Today’s top-shelf carbon fiber frames are stiffer than those old frames in every single dimension. Where they really differ is in the severity of road vibration they transmit. An equally stiff frame made from steel transmits more road vibration. What gets called “compliance” by most cyclists is really just vibration damping and the beauty of carbon fiber is that some carbon fiber frame have the ability to damp a broad spectrum of vibration so that the sensation isn’t so much wet blanket, but rather volume lowered. Kind of the opposite of the amp in “This Is Spinal Tap.”

Look, this one is turned down to five.

That said, there’s also some suspicion for the notion of torsional stiffness. To this I cry foul. When I began reviewing bikes I would spend some time making sure the shifting was adjusted perfectly to eliminate the ability of componentry to color my opinion of the frame building. It was only fair.

Next, I would take the bikes out and after I was warmed up I would do a few sprints in the 53×19 (assuming the cassette was a 12-23). On most frames, I could make the outer plate of the front derailleur rub against the chain. This was my standard litmus test for bottom bracket stiffness. On those occasions in which it didn’t rub, I knew I was dealing with a bike with a really stiff bottom bracket.

That didn’t happen much.

To resist torsional flex and twisting loads, the down tube is broadest on its underside, at the bottom bracket.

But bottom bracket flex isn’t the whole story. Not even most of it. Once manufacturers had largely addressed BB flex a whole new issue emerged: torsional flex. The issue is familiar to avid tandem riders. Those who rode tandem back in the days of small-diameter steel-tubed tandems will remember a phenomenon referred to as “lash.” Frame twist could be so pronounced as to cause the tandem to steer in one direction or another, making handling unpredictable. Compounding matters, wheels have gotten more flexible. Some 16- and 18-spoke wheels flex like the BB used to.

Carbon fiber frames still run the gamut on flex, mostly due to their forks. Some are sheetrock stiff while others are as flexible as bamboo shoots. Sit on the top tube of a bike and twist the handlebar and you’ll be surprised how often you’ll feel the bar twist slightly and the front wheel stand firm as the fork gives.

The fork on the Z1 is the same as Felt’s F1 with two minor changes. The dropouts are made from aluminum for increased durability while they are shaped slightly differently, giving the fork 50mm of offset. The steerer, the layup of the blades, all that is exactly the same.

This idea of creating exactly the same bike in two categories is significant to me. One thing I heard consistently from women when we reviewed bikes at Asphalt was that any time a bike was offered specifically to women it almost always featured either a watered down frame or parts pick. I knew a number of successful professionals who happened to be women and they felt consistently insulted by the fact that most of the time they couldn’t buy a bike made specifically for women that would also include a top-of-the-line parts pick of Record or Dura-Ace.

So one of my bigger pet peeves is an indication by a bike company that only racers will have reason to buy an ultra-light bike with Super Record or Dura-Ace. Honestly, how many people who are racing out can both afford Super Record and would choose to race it given how much of it is likely to disintegrate in a crash?

The carbon fiber blend that gives Felt’s F1 such a distinctive feel is present in the Z1 as well as their women’s frame, the ZW1. The ZW is essentially just Felt’s Z geometry in women’s sizing.

Other than a change to the dropouts, this is the same fork used on Felt’s F1 bike.

Back to that whole flex issue. Builders who chose to builde with Columbus tubing back in the 1980s had to choose on what size frames they would begin to blend Columbus’ heavier SP tube set in order to offset the stiffness loss of the larger frame sizes. It was not uncommon to find a 56cm frame built entirely from SL while the 58cm frame featured an SP down tube for some additional stiffness while the 60cm frame would be built entirely from SP. Well carbon fiber allows you to tailor each frame’s material usage to get exactly the right flex pattern.

Because there is no limiter forced by the raw materials, Felt changes the amount of material in each frame size of the F, Z and ZW bikes. Because the ZW bikes are the smallest frames intended for riders likely to be a bit lighter, the ZW1 is actually Felt’s lightest carbon fiber frame, weighing roughly 800 grams in its smallest size.

Why do this? Imagine having the ability to create frames that offer the same flex pattern in every size. Imagine knowing that your riding experience is the same as someone four inches taller … or shorter.

When shopping for bikes, fitting is the crapshoot. Until you take a serious look at the geometry, there’s no way to know if you can fit on a given bike. Between the Z-series frames and the ZW-series (women’s) frames, the Z is available in nine sizes. From smallest to largest, the top tube lengths are as follows: 49.7, 51.5, 52.5 and 54.5, for the women’s bikes and 52.5, 54.5, 56, 57.5 and 59.5cm for the men’s bikes. I could easily have ridden the 57.5cm top tube bike, but selected the 56 due to the length of the head tube and my desire to keep the bar relatively low, while avoiding the change in handling brought about by using a really short stem.

With only five sizes for the men’s bikes there are definitely some holes in the sizing run that could be problematic for some riders. The 1.5cm jumps aren’t too bad (or uncommon), but the 2cm jumps between the 52.5cm and 54.5cm top tube bikes could pose a fitting issue, as could the 2cm jump between the 57.5cm and 59.5cm top tube bikes.

Let’s talk absolutes. I’ve ridden frames stiffer than the Z1. I’ve not ridden one lighter in a 56cm frame—my frame weighed in at 908g. It’s in a dead heat with the best frames I’ve ridden in terms of ride quality. It retails for $2599, about $200 more than Cervelo’s RS and $100 less than Specialized’s Roubaix SL2.

By creating two bikes so very similar in so many aspects, the folks at Felt brought focus to a point that doesn’t get much attention these days: geometry. At the end of the day, the only meaningful differences between the F1 and Z1 are how they handle.

The Z1 reminds me of nothing so much as the Italian road bikes I often reviewed a dozen years ago. It’s calm in a straight line, turns in easily and is responsive in a sprint.

The wishbone junction is clean and features simple lines.

It was at the Markleeville Death Ride nearly Lake Tahoe that I had a revelatory experience. Descending Carson Pass in a painful hail storm (I know, that’s redundant) I began to catch a 3-series Beamer at 40 mph. I couldn’t see much other than the yellow lines to my left and the white line on my right and yet I felt calm and secure. The Z1 was rock solid.

The bike’s only weakness emerges at truly high speeds. I’ve found that once I’m above 45 mph the front end starts to get a little loose, twitchy. I haven’t experienced anything as bad as a speed wobble at those high speeds, but the bike’s unperturbable nature begins to falter. In the grand scheme that’s happened fewer than 10 times and I have more than 2000 miles on this frame.

The bike industry is full of good, if ordinary, bikes. There are a number of impressive bikes as well. There are a handful of truly extraordinary bikes. The shame is that Felt’s Z1 could easily be lost among not the ordinary, but the impressive. It’s far more than that.

(A quick note on bike scores: I’ve decided I’m going to score bikes a little more stringently than I did in some of my previous reviews. I’ve revised those scores down and scores in the future will reflect that as well.)

Felt Z1: 95 points