Road Rider Air Forks
Road Rider Air Forks
EVALUATIONS
One of the few actual criticisms contained in our test of Honda's CX500 concerned the front forks. They give generous travel, soak up little bumps and ripples and don't have much stiction. They are soft, which means the ride is smooth and comfy and adds to the pleasure of the bike.
Soft also means (in this case) that it’s possible to bottom the front end on a pot hole. And under full braking, the fork sinks to the stops, at which point there is no front suspension and the wheel can hop on the pavement, which makes braking a bit more difficult.
No big thing, and for most riding conditions a situation that can be lived with.
Unless you don’t have to. And you don’t, thanks mostly to motocross engineering and the accessory people.
Long travel dirt bikes have much the same problem, that is, the long and soft front end works fine until you use all the travel, so the off road crowd began adding air pressure to the forks several years ago. A sealed air space is a spring. Better, it’s a progressive spring. The more you compress it, the stiffer it gets. Several production motocrossers come with air fittings on the fork tubes, and several top-of-the-line street Suzukis and Yamahas have the same feature.
Honda hasn’t gotten around to air forks yet, but soon as we found the CX500 had a problem which lent itself to the system, we checked catalogs and found an air fork kit for the CX500, offered by Road Rider Accessories, Inc.
The kit is complete. There are two caps, which screw right into the stock tubes. Each cap has two threaded holes. There’s an air valve, two fittings for a plastic balance tube, and a neat little pressure gauge. The four bits that screw into the four holes interchange, so you can check clearance at the top of the tube and then put the valve, the balance tube and the pressure gauge wherever they won’t interfere with the bars, cables, etc.
In the case of the CX500. the gauge went at the upper left, the tube from lower left to lower right and the valve at upper right.
Installation took maybe 20 minutes. (The instructions are clear, albeit they deal with the kit more than with the model being fitted.) No special tools were needed, except that because the CX is fairly heavy, and the fork springs are preloaded, we had one man muscling the cap into the tube with the handle of the shop hammer while the other man spun the wrench. With caps in place, the fittings were screwed in, after being dabbed with sealer.
A few strokes with a small air pump and the system was ready.
It works. We did some experimentation with initial pressure settings and found that at 8 psi there was no change in ride over ripples but some added stiffness on bumps. The forks could still be bottomed under maximum braking, although the stops weren't as obvious nor did the tire hop as noticeably. Pumped to 20 psi, the practical maximum, the air pressure does prevent bottoming under any loading less severe than a trench in the road. But the ride is noticeably more firm and a little of the supple comfort is lost. Braking control did seem to be improved, although we could not measure a difference.
Using higher pressures also showed that the screw-on valve on our pump wasn’t adequate. Pressure changes involve a tiny amount of air, which leaked down while we were removing the pump. We wound up using a home workshop compressor, with snap-on valve. This isn’t exactly a flaw, but it does mean you’ll need to have a pump in your tool kit if you want to vary pressures on the road. Conclusion: the air caps do help. They’ll be useful for add-ons like fairings or for extra loads and they do improve braking without major loss of comfort. But perhaps because road bikes are heavier and have less wheel travel, pressurized forks don't seem to have the effect on road bikes that they do on dirt bikes.
Road Rider offers kits for most popular big bikes, for $32.95. They're sold through retail stores, so check your local dealer or have him order through the distributor. Helmet House, 2115 Colorado Blvd., Santa Monica, Calif. 90404. gj
