Tiong Hin Co Tyre – MTB Zone

Dirt Rag Magazine sat down with Pivot’s fearless leader earlier this fall and downloaded him on everything Pivot. The interviewers did a great job of getting inside Chris’s head and got a great picture about Pivot’s philosophy, our attention to detail and got a great lesson on suspension theory. The article, with a review of the Mach 5, is on newstands now. The Mach 5 review is online now, too: http://www.dirtragmag.com/print/article.php?ID=1246&category=stuff_reviews

The 140mm-travel Mach 5 is Pivot’s vision of the proverbial “jack of all trades” mountain bike. Pivot’s head honcho, Chris Cocalis, described his approach to the Mach 5: “The whole idea of the bike is that it has neutral handling, not overly slow nor overly quick. Some of the newer 140mm bikes fall more toward a ‘freeride-light.’ But the Mach 5 falls more toward our cross-country based bikes. It has all the capabilities, but at the same time has the pedal feel that somebody would feel comfortable doing an endurance event or 24-hour race on this style bike.” I totally get the idea of having “one bike that does it all” and was anxious to evaluate how well the Mach 5 fared in the pursuit of that lofty goal.

To kick off this test, Chris Cocalis stopped by Dirt Rag HQ to talk tech, and join the staff on a group ride. Chris gave us a primer on the dw-link rear suspension that Pivot uses on their bikes. The brainchild of Dave Weagle, the dw-link is a version of a dual-link suspension, where there is an upper and a lower linkage. According to Chris, a key benefit of any dual-link bike is that the wheel travel path doesn’t have to be one constant arc, it can be an S- or a V-shape, something other than an arc. The Pivot suspension has a rearward wheel travel path in the first part of the travel, designed to produce better square-edged bump performance and allow the suspension to roll through the smaller trail junk a lot easier….

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DR: Can you start by talking about the Mach 5 bike design?

CC: The Mach 5 is a 140mm travel bike. Some of the newer 140mm bikes fall more toward a “freeride-light.” But the Mach 5 falls more toward our Mach 4 or our 429, or cross-country based bikes. It has all the capabilities, but at the same time has the pedal feel that somebody would feel comfortable doing an endurance event or 24-hour race on this style bike.

The whole idea of the bike is that it’s neutral handling, not overly slow or overly quick. It also climbs really well and doesn’t flop around in the front end. It steers slightly to the quicker end, compared to something like the [Santa Cruz] Blur LT. I use that comparison because it’s a good baseline and a lot of people know how that bike behaves. This [Mach 5] is the one bike that really does it all. If you’ve got a bunch of bikes in your garage and you’re not sure if the bunch of guys or girls that you’re going riding with are going to hammer the hell out of you, or take you on super-technical stuff, this bike will do everything.

A few of the things that kind of define what Pivot is: we really focus on frame stiffness. The lower linkage has eight cartridge bearings in it. We were the first people on the mountain bike side of things to develop an oversized, press-in bottom bracket. We actually developed it with Shimano, it’s a 92mm wide BB, the shell diameter is larger than a standard thread-in bottom bracket [shell], and the entire XTR bottom bracket presses in. With the wide BB, the bearings are in the same relative position as they would be in a thread-in external cup, but they’ve got better support all around them with the bigger shell. They’re more protected inside the shell. Because the load of the bearings is sitting right on the frame, instead of hanging out off a threaded section, you don’t get the tendency for threads to pull and creak. It eliminates a lot of set-up problems like: is the bottom shell faced correctly? Is the distance from seat tube to the drive side face absolutely correct, so the chainline is correct? With that 92mm shell we can get our pivots a lot wider, the downtube can be wider, and everything down there can be bigger and stiffer without adding weight.

DR: How many different bottom brackets are compatible with the design?

CC. Well, when we first developed this, we did it solely with Shimano. Every frame ships with an XTR bottom bracket in it. Even on this bike with our XT/SLX kit, the bottom bracket is an XTR, which comes with a three-year warranty, so you get a much higher-end bottom bracket than what’s typical. That design is also compatible with FSA and Race Face cranks. They’ll just slide right in there. FSA now makes a press-in bottom bracket with ceramic bearings that’ll go in there. But it’s actually heavier than the Shimano bottom bracket that’s in there.

And we’ve actually been working for the past six months with SRAM on a composite press-in BB, because the Truvativ GXP cranks have the floating bearing—they’ve got two different sized bearings. We’ve got the final pre-production stuff at the office. So Pivots will now be compatible with any Truvativ/SRAM crank. The new SRAM XX group is coming out and we wanted to make sure that, with the [XX] 2×10 stuff, particularly on our Mach 4 frames, that we’re compatible with every crankset on the market.

The other thing is, around that bottom bracket area we basically start with two forged halves and weld the bottom bracket shell together. Then the entire unit gets put on a CNC machine and all the tolerances are properly held. The front derailleur mount is machined into the right-side forging, and it’s a direct-mount front derailleur so it uses an E-type style that bolts right on. Again we’ve been working with SRAM and they will this year [2010 model] have a front derailleur for their XX that will bolt right to that same mount.

And between the 92mm bottom bracket shell and the direct-mount derailleur you get a much more precise set-up. Again, there’s no facing needed. That’s one of our key quality control checks on every frame—we measure from the face of that derailleur mount to the outside of the bottom bracket so that we know chainline is perfect on every bike. When we send out a complete bike the front derailleur is mounted and the bottom bracket’s in.

Because the mount is directly on those forgings it’s really the most rigid front derailleur mount on the market. When we first came out with Pivots and were at the first Interbike, we were talking so much about the suspension design and everything, and people would come back and go: “Wow, I’ve never been on a bike that’s shifted like this.” It’s instantly noticeable that all those things add up to a very immediate shift, and there’s just no flex in the system.

The head tube of the bike—we use a 1 1/8″ zero-stack [headset] on it. It’s not an integrated. It’s actually 1 1/8″ cups that sit level with the head tube. That allowed us to do a couple of different things. The head tube gets much larger. The outside diameter of the head tube is very close to the size of a 1.5″ head tube. So it allows us to have bigger tubes coming into the head tube. With the bigger tubing, we get better front-end stiffness. You don’t have to squish the tubes down—overall better frame stiffness.

The zero stack also allows us the ability to take over an inch out of the front end [height] of the bike. In some cases, like a medium or a large frame, it’s not a big deal—we ship a tall headset cap with the bikes. When you’re talking about some of the other sizes we do, we have an extra-small frame that is like the lowest stand-over 5.5” travel bike on the market, with a women-specific geometry. And that lower front end goes a long way to achieving that stand-over. If you’ve got somebody who likes a longer top tube and wants to get into a racier position, that applies a lot more to the Mach 4. And it’s a really big thing on the 429—keeping that front end down.

And you know on longer-travel bikes, a 5” to 5.5” travel bike used to come with a 125mm [travel] fork and then they were 130mm and now they’re 140. And we’ve got a lot of customers buying frames and putting the new 150mm Fox on there. A few years ago when the new standards came out, they increased the minimum clearance between the tire and the arch, so all those things keep creeping up the length of the fork. Kind of going back to that versatility of using the bike for everything, all the way to endurance racing and sport-level racing, and [the zero stack headset] keeps that front end height in check.

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