21 April 2008

bikefix Exclusive Review: Pivot Mach 5

I was in a friend's bike shop the other day while a gentleman, who owned a hardtail, was shopping for a full suspension bike. Like me (and that shop's owners), he claimed to enjoy longer cross country rides in the mountains. Around here that means plenty of climbing and no shortage of techy bits or rock gardens. After the gentleman described his riding habits and favorite trails, the owner suggested a couple of 5in travel bikes in his price range (including a Rocky Mountain ETS-X, which Charlie reviewed a while back). Hearing that, the shopper recoiled, saying that he really didn't need that much travel and was really looking for a 4in bike. That would have been many of us a couple of years ago. However, as suspension designs have evolved, many bikes in the ~5in travel range (front & rear) have become extremely efficient, versatile and light weight- perfect for long mellow rides, trips to Moab and the occasional XC race.

Pivot's Mach 5 is just such a bike. There is a broad spectrum of bikes available with between 4.5 and 5.5in of travel front and rear. Despite it's 5.4in of travel, the Mach 5 sits squarely at the XC end of the spectrum. Looking long, lean and agressive sitting still, the Pivot's ~6.25lb/$1900 frame uses a modified version the DW-Link suspension design shared by Iron Horse and Ibis. As a former Ibis Mojo owner, I was curious to see if the Pivot was simply an aluminum Ibis or something different. Similar to Santa Cruz's VPP, the DW-Link uses a pair of stout links to create an axle path and shock leverage ratio that can be tailored to provide a number of different ride characteristics (such as squatting, not squatting, minimal chain growth, linear spring rates, progressive spring rates, reduced pedal-induced bobbing and combinations thereof). As a moderately agressive 145lb XC rider who likes technical climbing as well as descending, I came into this test having never ridden a virtual pivot bike that I liked. Blur? No. Ibis Mojo? Sort of. Intense 5.5 EVP? Awful. Crazy, eh? Here's why: most virtual pivot bikes are set up to minimize bob. Everyone pretty much admits that bob (rider-induced suspension movement) is a Bad Thing. Everyone, in this case, extends to include suspension manufacturers. Fox's Pro Pedal, Rock Shox's Motion Control and Manitou's SPV are all damping schemes that work hard not to respond to low speed, low frequency inputs. In fact, it's gotten hard to spec a decent quality rear shock that doesn't have some sort of platform damper or aggressive low-speed compression damping. The result, especially for those on the lighter end of the bell curve, are bikes that are somewhat dead feeling- especially over smaller bumps. My Mojo was a great example. It was light and pedaled well and a remarkable bike in a number of ways. However, the rear suspension's reluctance to move over smaller stuff, a slightly flexy rear end and the short (for a Large) top tube left me wanting. If you've just dropped $2k on a frame, there certainly shouldn't be much wanting. "But wait!" you're saying, "I love my Mojo/Blur/Spyder!" Good- you should love your bike. When it comes time to upgrade, though, there are an increasing number of bikes on the market that not only pedal well, but work on both large and small bumps.

Our demo Mach 5 came wearing its mid-range ($4200 complete) XT build kit. Something that I love to see is a build kit with no funny business. No Deore hubs, no cheap cranks, no house brand bars. Shimano's 2008 XT kit is fantastic, with smooth shifting, a cool low-profile Shadow dérailleur and powerful (but controllable) hydraulic discs. Speccing straight XT isn't cheap, but it ensures that no one part on the bike is particularly heavy or will wear out prematurely. A Ritchy Pro bar, stem and seatpost aren't fancy, but are both light and strong while being reasonably priced (the bar is a bit narrow but still comfortable). This bike's parts were clearly chosen by someone who actually rides. The only disappointments are the WTB saddle and grips- after 60 miles in one weekend, my bottom was bruised and my palms tender. Most everyone has their favorites, though, and at this price, your dealer should be more than willing to help you get things tailored to your liking. This was my first experience with Shimano's new (and fairly normal-looking) M-775 XT wheelset. They're a reasonable 1700g, stiff, tubeless and servicable- what's not to like? The hubs feel like they have far quicker engagement than older Shimano hubs and sound like Industry 9's wheels- at 1/3 volume. Very cool. The rear hub did sound a bit like the bearings were dry, though, but I didn't pull it apart to see (it's easy enough to add grease to them and again, your dealer should sort you out there).

Further proving that Arizona-based Pivot guys actually ride (in the Southwest, no less), the tires were a fantastic Kenda Nevegal/Small Block 8 combination. They won't be everyone's choice, but the Small Block 8 in a 2.35in width is both grippy and fast and the pair was great in hard, rocky and loose conditions. They're one step shy of perfect, though, because tubes are lame. On a bike made for high speeds and rough terrain, they're a liability. I went through nearly $30 worth of pre-slimed tubes in two rides. That's more flats than I've had in the past year (and enough to pay for an upgrade to tubeless). I was even running my usual 30psi front/35psi rear (remember that I weigh 145lb). My pack, gloves and shorts are all stained with sealant and I missed an appointment as a result. I know that there are people who hate tubeless tires without even having had to try them, but they'll be kicking themselves when they finally do. Tubes suck. It's got tubeless rims, guys- come on. There are a couple of interesting things going on behind the cranks that are worth mentioning. The E-Type (or very similar) front dérailleur is solidly mounted to the frame, providing nice solid shifts and keeping out of the suspension's way. The bottom bracket cups are pressed directly into an extra-wide shell, something that's becoming increasingly popular on road bikes. This means that you're tied to Shimano in both cases, but these parts are fairly problem free, and the space saved allows for uncompromised pivot placement. If you're planning a road trip to someplace remote, though, carrying a spare front mech may be a good idea.

The bikefix crew got together for a nice mini-epic the other day so that we could swap gear, take some photos and go for a ride. I brought both the Pivot and my personal bike (a Maverick Durance) so that we could swap back and forth during the ride. Over a few days, I put in between 75 and 80 off-road miles between the two bikes. While it's not not enough time to really speak to the Pivot's durability, we managed to get a very good feel for how the bike performs.

In short, the Mach 5 is far and away the best virtual pivot type bike I've ever ridden. Designers Dave Weigle (DW-Link) and Chris Cocalis (formerly of Titus) have done a good job at making a bike that feels snappy out of corners or while climbing without giving up plushness or small bump sensitivity. An initially rearward axle path does a very good job on not only small bumps but the kind of steppy, ledgy stuff that's common both in New Mexico and New England. I was surprised, to be honest, until I had a closer look at the rear shock. While the long-ish stroke (low leverage ratio) was no doubt part of it, Pivot are the first company that I've seen to spec the Fox RP23 shock with the lowest compression damping available. There's a little 3-bar graph on the shock (sort of like the old Cingular logo) that states the amount of factory-set compression damping. The Mach 5 is at 1 (of 3) and it makes a huge difference. Set the sag to about 30% and turn the Pro-Pedal lever to Off and you're done. While there is some occasional pedal kickback, the suspension seems very efficient under torque. It snaps out of corners like few other bikes I've ridden and never feels like it's bogging down while siting. When pedaling out of the saddle, it does get a bit mushy, but no worse than the competition. While I never felt it bottom out harshly, the o-ring on the shock shaft told me that I was using all of the travel. Launching into rock gardens at speed was a blast (explaining the flats?)- the suspension handled successive hits in a very controlled fashion. More than anything else, the rear suspension reminds me of my 2003 Giant VT-1 (a moderate travel single pivot with a linkage-driven Manitou SPV shock) but snappier.

As well as the bike climbed, though, I had a hard time keeping the front wheel down while climbing. Despite the 110mm stem (an odd choice for a medium-sized frame with over 5in of travel) and reducing the TALAS fork to its 120 or 100mm setting, the front end of the bike had a bit of wanderlust on the climbs, which is hard to explain. One indication of how well the rear suspension was working was just how bad it made the Fox TALAS fork feel. I've never been a big Fox fan, but the better a bike's rear suspension works, the worse they tend to feel. The TALAS, in particular, seems to suffer from excessive high-speed damping and/or stiction- when set up soft enough to feel decent, it blows through all 5.5in of travel at an alarming rate. Dan (formerly of Manitou) has been playing with 5wt oil in some Fox forks and they do feel better, but an $800 fork should probably work well straight out of the box. Luckily, Fox have a fantastic resale value, and your dealer may be able to swap it for a better fit for a few bucks- maybe for a new Minute or Revelation. I liked how the bike felt with the fork set at 120mm (with a 70 degree head tube), and extending it to 140 was nice for longer or rougher descents. While the Mach 5 really comes into its own at speed and on sweepy motorcycle trails, it did feel a bit odd in slower situations. Turns at lower speeds required conscious steering rather than leaning or carving. This made more trials-y moves a bit difficult, but with more time on the bike I think that it'd be fine.

While two bottle cage mounts are appreciated (one set on either side of the downtube), the one inside the main triangle is really wedged in there. Forget about running a large bottle, and it can be a bit of a struggle to get a small bottle out of the cage while riding thanks to the knobs on the shock. Some sort of alternative side-entry cage might be in order if you'd like to keep your bottle out of the path of logs and/or manure. All in all, the Mach 5 is an impressive enduro bike. It pedals well and has the ability to compensate for some spectacularly poor line choices. It rewards the rider for carrying speed, which is a blast. $1900 for a Taiwanese made boutique frame isn't unheard of, but it could be a hard sell against the arguably sexier Ibis, which comes with an XT kit, Easton carbon bar and seatpost (but cheaper Easton non-tubeless wheels) for the same money. If you're in the market for an all-around bike or frame, though, the Mach 5 is certainly worth a demo. The Pivot is, put simply, the bike that I wanted the Mojo to be. I'm not going to rush out and sell my current bike, but if I were in the market, it would certainly be on my short list.




Steve said...

Great, thorough review. I just rode the Mach 5 at the Fruita Fat Tire Fest and was very impressed. I went to the fest specifically to ride the Yeti 575, and the I found the Mach 5 to be the bike I hoped the 575 would be. Now, I need to figure out how to make it work financially...

bikefix said...

Steve, Thanks for your comments. We've heard good things about the 575, but haven't had a chance to put any time on one. The Mach 5 certainly is an impressive ride and their getting the bikes out there is a good thing- for that kind of money, you should ride as many of your options as possible... Good luck with the financial wrangling, marc