Chalo
100 TW
full-throttle said:
I'll leave out discussion of my motorcycles, a Honda VF1100S, Suzuki GSX1100G, and Suzuki GS850G, all of which I tuned to one degree or another with springs and valves for above average loads.
Of bicycles I currently own and ride, one is equipped with a highly modified Specialized Future Shock Carbon fork whose travel I shortened from about 50mm to about 35mm for road use. It's an air/oil fork that I fill to about 70psi, with 10W fork oil. I usually back the rebound damping out most of the way. I've had it a long time, I made many parts for it, and even though the bike would be lighter and neater with a normal fork or even a non-suspension version of this fork, I like it the way it is as an artifact and a worthwhile experiment.
Another bike of mine has a 2003 Marzocchi Marathon 29er fork modified with stiffer springs (I forget the rate, just the stiffest ones Marzocchi offered), slightly heavier oil, and longer preload spacers. I did the mods to keep static sag to about 20% of the total 80mm travel, and increase damping rates to balance the higher than stock spring rate. This is the longest and most active fork I have used on my own bicycle, and the bike is noticeably slower than it was with its original rigid 29er fork. I give away about an inch worth of the work in each pedal stroke every time I pedal hard.
In the 20th century, I had a 26"/700c street bike with a suspension fork. I used a 700c Manitou elastomer fork with hard elastomers and the preload cranked all the way up. Travel was left stock at about 45mm, give or take.
I built a chopper bicycle with a cheap but reasonably functional Chili Gordo triple clamp type fork, for which I machined a new steer tube assembly so that I could use it as an extra-long single crown fork. It worked well enough for a low-performance chopper with a lightly weighted front end.
During the time I bought and set up all these forks, I was accustomed to keeping my tires inflated to their maximum rated pressure, if not higher. I was operating on the assumption that tire pressure should be somewhat proportional to rider weight, and during that span of time, my weight ranged from a rather lean 280 pounds (at 6'8" tall) to a rather fat 410 pounds or so. I was leery of pinch flats and wheel damage that would occur if I bottomed out my tires, so I erred on the side of too much pressure.
When I made what was to me a leap of faith and began to use normal tire pressures well within the recommended ranges on my bicycles, I found that, like my motorcycles, my bicycles worked better with comparatively soft tires, of however large a size was necessary for the application. Since that time, I have not wanted or acquired any more suspension components.
When I got hip to letting fat tires do their job, 2.5" was a super-fat 26" tire and 40mm was a super-fat 700c tire. Now you can get MTB tires up to 4.7" and 700c tires up to 76mm, with frames and rims to suit. There is less and less justification for mechanical suspension on bicycles that operate on paved surfaces at moped speeds or lower.
The most extreme e-bike is not practical or comfotable either, and neither is the most extreme example of a DH bike, trials bike, or any other single-purpose machine.
Efficiency penalties stack up on each other; you want to incur as few as possible within the constraints of the bike's purpose, if you want the best performance for a given amount of power. (Or conversely, if you want to use the smallest possible amount of power to do a given job.) So it may make sense to have an upright riding position for comfort, traffic visibility, and compatibility with normal clothes, and it may make sense to use fat tires or a heavy bike for durability, low maintenance, and fault tolerance. But if you add unnecessary mechanical suspension to these other efficiency compromises, then you lose even more performance and add cost without adding functionality on the street.
It's easy to get stuck in a sort of motor vehicle vicious cycle where you need a stouter bike to support the power and weight of your electric assist, but that costs performance. So you add more power, and with it more weight. Then your bike has to be more heavy-duty. And so forth. What you end up with is a crude, gimpy motorcycle instead of a self-propelled bicycle.
In terms of day-to-day practicality, suspended bicycles (especially rear suspended bikes) are far inferior to normal bicycles. They don't support normal luggage accommodations or frame mounted accessories, and they offer much less in the way of mounting options for electric systems. They don't fit properly in service stands or on carrier racks. I never for a moment considered a suspended bike for any of my own e-bike projects because they seemed seriously impaired for such adaptation. That said, the first e-bike I built for someone else back in about 1999 had a Manitou elastomer fork and a Softride beam mounted seat.
I'm not allergic to suspension in principle. I just think it's just the wrong tool for the job in this case.
