Monday, September 15, 2008

dw-link / Turner damper testing

On Thursday night of last week, I headed off to sunny Murrieta, California (about a 9 hour trip across the country for me) to finish up some suspension testing with Turner bikes. Dave Turner and I wanted to try to get all of the FOX damper tunes that we have been playing with finalized for the big On-Dirt Demo at Interbike. This is where the Turner Bikes faithful will get to ride the new dw-link bikes for the first time. (note: if you are a rider and want to get out and feel the bikes for yourself, this is the place. dw-link bikes from Ibis Cycles, Pivot Cycles, Turner Bikes, and Iron Horse will be there and ready to ride. I'll personally be at the event under the IBIS, Pivot, and Turner tents on the 23rd to answer any questions that riders might have. Plus, I'll be there to ride!

This is the type of testing that I o with all of my suspension licensees, sometimes in person (like when I flew to Arizona to visit Pivot Cycles in July (pre-blog, sorry!)) and quite often here on my home trails.

Typically we would have been joined for our suspension testing by one or two representatives from our suspension partner FOX Racing Shox, but this time, most of their staff was attending the World Cup downhill finals in Schladming, Austria. We invited along two well known locals for our second day of testing, our friends Chris Lesser and Alan Davis, both of bike magazine. We rode on their local trails, a mix of climbing, square edge hits, fast off camber turns, and very little traction. This was the perfect place to really feel out the differences in traction and compliance between different setups.

This type of testing is a little different than your normal ride. We usually work on short loops of trail, testing different settings and noting the riding perceptions for each test while we switch out shocks or settings. We switch bikes frequently and talk through each detail as carefully as we can. For some sections of trail we use a spotter to observe suspension action, and on other sections the rider observes on their own. We look for specific suspension traits which can vary depending on the bike, setup, or test. It's quite a bit more work than your average ride.

Chris, Dave, and Alan posing with the new Turner 5-Spot

The new 5-Spot, 140mm of trail eating travel

Talking about the "feel" of the bikes and the settings changes that we tested on the last run.

We ended up working on 3 bikes during our two days of testing.

On the first day, Eric from Turner, Dave Turner and I dialed in the new 100mm Flux's damper settings. The bike was designed to use either the small or large air can Fox RP23 shock. Our FOX RP23's were the 2009 spec, with light compression and light rebound settings. This particular shock has a lever that can actuate what FOX calls "Propedal". Propedal is essentially a low speed compression increase that can be actuated by the rider by flipping a lever on the shock. With a separate setting on the shock, the rider can choose between 3 levels of Propedal that will kick in when the lever is flipped, with level 1 being the least amount of compression damping, and level 3 being the highest. We found that our bikes had the best traction in all riding situations with the Propedal lever turned off, as is usually the case with dw-link bikes. We did specific testing to assess how well Propedal could help on standing climbs. We found that the best traction was had with the Propedal lever in the off position, and that for riders who really "mash" out of the saddle that level 1 could control their excess body movement with only a small traction compromise. Levels 2 and 3 provided no benefit, but less observed climbing traction (more wheelspin) during testing. (keep in mind that many bikes use a LOT more compression damping than the dw-link, and the traction loss with higher levels used on other designs is immediately noticeable.)

We will work on dialing in other shocks including the Rock Shox Monarch over the next couple of months. Additionally, Darren Murphy from PUSH Industries took the time to send over a couple of specially tuned RP23's that were designed with special valving that really lets the dw-link take full advantage of available traction. These special valved shocks are nearly unusable on other suspension designs, but the dw-link with it's position sensitive anti squat can run a significantly more compliant shock setup than other designs. The proof is in the ride, and the ride, compliance, and traction were amazing for a 100mm travel bike.

On the second day we tested the Flux again, along with the 5-Spot (140mm travel), and Sultan (29" wheel 120mm travel).

Chris Lesser was a sport and rode the 29er' hard for us. Wheel rate wise the Sultan is in between the 5-Spot and Flux. It has XC feel, with long travel trail bike compliance and a little end travel ramp to soak up the big hits. We knew what to expect with the Sultan, and there were no surprises. It rode just like a 5" trail bike, with all of the advantages and peculiarities of a 29'er. Shock setting wise, we liked the XV air can on the RP23. We preferred the Propedal off for all conditions, and one thing we observed was how planted the rear tire was on the standing climbs without extra compression damping. The dw-link was really working quite well on the Sultan, just taking advantage of that big contact patch. It was pretty cool watching it work, and I couldn't help but to feel psyched to see it doing exactly what it should. Like the Flux, for riders who really mash the pedals, Propedal 1 will work, but it would probably work better for riders like that to work on form and take the traction instead. To each his own though!

The 5-Spot is a uniquely cool dw-link trail bike. It was really designed to use the XV RP23, which in the 190mmX51mm size features a very low air spring compression ratio. We designed a bit of ramp into the wheel rate, and the leverage rate stays progressive throughout the travel. This makes the suspension really compliant early in the travel, with a little spring ramp in the end and a nice controlled damped feel at the end of the travel. It hooked up hard in the corners and soaked up the little drops around the trail with ease. We preferred the Propedal off for all conditions, even for standing climbs. Like the other bikes, real mashers could use setting 1 for the standing climbs, and settings 2 and 3 should probably be avoided. I am looking forward to testing this bike with a coil-over shock, I think that it is going to really work out nicely.

Darren from PUSH worked his magic on a shock for the Spot too, and as expected, it was also brilliant. That dude knows what's up when it comes to damper tunes.

OK enough blogging for today, more tomorrow.

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