07 October 2007

bikefix midterm Review: Marzocchi XC Retro SL 700

The Marzocchi XC Retro SL 700 is an odd duck. Not only because of the long and unwieldy model name, but because it defies easy catagorization. Weighing in at 3.5-3.6lb, its on par with Rock Shox's Reba and Fox's F100 series. With adjustable travel from 90-130mm, its closer to those companies' Revelation and TALAS models. As a result, its a bit heavier than a full-on XC 'race' fork without being as heavy or stiff as what's being called an 'all mountain' or 'trail' fork.

Available only in white (boo!) with naff faux-carbon decals (ugh), this fork also has, oddly enough, optional v-brake bosses, and a somewhat functional hose-management system (we still had to use one zip tie to prevent the hose rubbing on the front tire). The stantions are nickel-plated and quite shiny, though they don't quite match our polished Formula Oro Bianco brakes. Marzocchi have done away with their tiny valve adaptor in favor of nice, standard Schrader valves. There isn't a ton of tire clearance, but 2.2s and 2.3s fit just fine.

We've been riding this fork on and off since last November, when they landed in the US. To be honest, after being very happy with 2004 and 2006 Marathon SLs (this fork's predecessor), in their 120mm versions, we were pretty disappointed right off the back. In place of the Marathon's adjustable positive and negative air springs were two positive air chambers. The adjustable negative springs allowed us to set up the Marathons to work very well over small bumps yet remain progressive enough to prevent bottoming. The XC700SL (for short) instead uses what is effectively a two-stage positive spring. In theory, this would allow good small-bump sensitivity (through low air pressures) for the first third or so of travel and bottom-out resistance from higher pressures in through the remainder of the stroke. Thanks to awful rider weight-based recommendations in the manual (far too high), it took a lot of experimenting to get right and, once set correctly, stiff seals throughout meant that the transition between springs could be felt while riding. Small bump sensitivity was nowhere near where it was with the Marathons, which was a huge disappointment.

But what was good? The ATA travel adjuster, while nowhere near as nice as Fox's TALAS adjuster was easy enough to use, thanks in part to the flip-up 'wings' on the adjuster knob (right)- easy to use with gloves and no sharp edges at all. Can't complain there. While a bit harder to grasp and turn, the 5-position TST compression damping adjustment (full open to lock out) worked well. We liked it full open most of the time, but racers and bob-o-phobes would likely have liked one click in. The lockout worked well, with only the audible gasp of a blowoff valve reminding you that you really should have turned it off if you were going to be doing any drops.

The fork felt good, then, on isolated bumps. Really nice, that is, until it found itself in a rock garden, at which point it became overwhelmed and stopped working. This was odd and very, very bad. Furthermore, on occasional high-speed (25mph+) hits, it would suddenly blow through its travel, almost like a massive blowoff valve had opened. All of it. It didn't happen often, but it sure was scary when it did. So, a Pace was ordered up and back to Marzocchi it went under warranty.

The fork came back in about a week (very good), but as there were Paces and Fox's to try, it sat for a while before being ridden again. Marzocchi had updated the internals to whatever was 'current' mid-summer (it sounds like there have been a few running changes) and the fork felt immediately better.

At full travel, the XC700SL is visibly flexy fore and aft, though we didn't feel it much except under hard braking. at 110-120mm or so, though, it seemed both stiffer and to work better on small bumps, so we took to winding it all the way out and then back in a turn or two, which made for a nice match with the 130mm of travel on the Maverick ML7/5 and Durance it was tested on. In fact, it made for a nice match to the bike overall. As far as air pressures go, Marzocchi have revised recommendations on their website, and we settled on 70psi and 100psi (top and bottom). We were able to use all of the travel without it being too dive-y or the transition between springs apparent. While not as plush over small stuff as the Marathons, it was far better than the 08 Fox TALAS, and almost as good as the coil-sprung Pace RC40 Fighter. Bigger riders may be bothered by a a bit of flexiness, but it is 1/2lb lighter than the longer-travel competition, so that's to be expected.

That was the review until the other day, when we noticed that the fork was winding down into its travel while riding. Its a bit disconcerting to get to the bottom of a descent and find your handlebars an inch or so lower than you expected and your bikes handling that much twitchier. Ready to send the fork back, we did a quick internet search and found a 3-minute fix. Using a cassette lock ring tool to remove the ATA (travel-adjustable air spring) cartridge, turn the ATA knob to a position between detents, and tighten the two set screws near the top of the cartridge almost to stopping. This increases pressure on the detents and reduces self-winding. Or so we thought. While the next ride saw far less shrinkage than previously, it would wind in a notch or two on rough descents. We'll keep an eye on it, call Marzocchi, and let you know.

While it seems like an odd fork, we'd consider it an aggressive XC fork- perfect for one of the new 5in (or so) travel XC frames on the market (Ibis Mojo, Ellsworth Epiphany, Blur LT, etc). Something that's at home for technical XC riding as well as the odd race or lift-supported day out. We were thrilled with the fork after it came back from its initial service, but the winding down is a problem. Which is a shame, because this is one of the only new forks we've ridden in the past year that we really liked. Given the terrible MTBR reviews, you should be able to pick one up cheap, though.

For 2008, it looks as though the XC700SL has been extensively reworked (including a new casting), which may well help things. They look to be available already. If they've addressed the flexiness and self-winding, we'd love to get our hands on one...


1 comment:

Michael said...

I know this is an old review but I had the same fork, the self winding was resolved with a new knob that Marzocchi provided. works like a champ now.