![]() ![]() But on the other hand, it may be too progressive for those able to run the recommended air pressure.īut I am not an unusually heavy rider - in fact, my weight is right in the middle of DVO's setup chart - so there's no excuse for it not working properly. That's arguably a good thing as there are no plastic volume spacers available to make it more progressive (although you could add oil to the air chamber to achieve a similar effect). I had no issues with undue bottom-outs despite having to run less air pressure than ideal. Friction and sensitivity once into the travel appears good too, although it's hard to be sure with such a compromised setup, and I had none of the random vagueness or jarring sensations you can get with a flexy fork. The range of damping adjustments is ample and intuitive, and even with the compression nearly fully closed, there was no hint of spiking or excessive harshness despite noticeable hydraulic support. (Remember, DVO recommends 80-85 psi for my weight and up to 100 psi for the heaviest riders).Ĭould it work for lighter riders? Probably. The OTT system just doesn't work for heavier (or average weight) riders as the coil negative spring simply isn't strong enough to balance out the force from the air spring with more than about 75 psi. Obviously, I reduced the pressure and slowed the rebound for testing, but it illustrates how much top-out force the fork is generating at and near full extension even with maximum OTT preload and recommended air pressure.īut ultimately, this is a band-aid solution. This video was taken with the fork set to 83 psi, with maximum OTT sensitivity and rebound fully open. With 80 psi, the fork was harsh at the start of the travel, leading to poor traction and predictability, but with 75 psi, the fork lacked support and dived too readily when braking or cornering. More to the point, I had to compromise between sensitivity and support. Unfortunately, I didn't get the chance to re-measure the fork at these settings, but the off-the-top sensitivity still wasn't as smooth as I'd like, though much improved. This helped a little, but the sensitivity still wasn't great, so I dropped the air pressure incrementally to as low as 75 psi. I soon adjusted the OTT dial to maximum sensitivity (which turned out to be fourteen and a half turns from fully off). Nevertheless, I could immediately feel that the fork was too stiff at the start of the stroke it wasn't engaging its travel easily, resulting in poor sensitivity, predictability and inconsistent traction. To avoid the problem of simply "feeling what I expected to feel", I started riding the fork before analysing the data from the spring tester above. Below are the recommended pressure and OTT settings by rider weight. If the fork is too soft or too firm in the beginning of the stroke, you have to repeat the whole procedure but return to the same pressure after adjusting the OTT.įortunately, DVO has a comprehensive setup guide on their website (there isn't a pressure chart printed on the fork itself). So, if you want a stiffer spring rate, you first need to measure the air pressure, release all the air, increase the OTT preload to match the higher pressure you're about to set, and then pump up the positive chamber to the new pressure. ![]() As we'll discuss below, it doesn't necessarily turn out that way, and it certainly adds complexity to the setup procedure because the air needs to be released before the OTT adjuster can be adjusted. The idea is that the rider can adjust the preload on the coil negative spring such that more preload causes the fork to sit deeper into its travel with a softer initial stroke, and less preload makes the fork sit higher with a firmer initial stroke. This increases the force pushing the fork into its travel, helping to offset the extra force from the air side, so the forces balance out nicely as the fork reaches full extension. If the rider increases the pressure in the air chamber, they'll need to increase the preload on the coil spring by turning the "OTT" (Off The Top) dial clockwise. This ensures the forces still balance at full extension, meaning the spring force goes to zero at 0% travel.īut in DVO's case, they use a coil negative spring below the piston, with a single air chamber above it to support the weight of the rider. Crucially, if you increase the air pressure, the pressure in both chambers increases by the same percentage. Most air springs have air above and below the piston, with a transfer port strategically positioned to automatically allow the air pressure on both sides to balance out so the fork requires minimal force to start moving into its stroke, but still fully extends to allow access to all the travel. Something that sets DVO's forks apart (aside from the polarising colourways) is the spring. ![]()
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