I ride with rigid forks mostly, because I’m not a mountain biker -any discipline of it- by any means, but sometimes it becomes tempting. I have a junk coil fork, in a city 1000 km’s away, where our second (or third) house is. I didn’ t bother to take it with me, because it’s really junk. But at some point, I missed a suspension fork and look for second hand ones.
Luckily, I found a RockShox SID, a quite old one, probably from 2005 or so. Price was so nice, 20$, which is way cheaper then >2.5kg coil forks with cracked legs. I knew what will happen next: a complete repair cost me over 60$, but still a fair deal, as almost destroyed coil forks are about 100$ second hand.
But to be honest, a coil fork would fit me better,because I don’t jump around – which is something air spring forks excel. Strange but coil forks, good ones with proper service history, is more comfortable.
Let me explain what are coil forks or air forks a bit:
They are like springs on your car. On one side, or both sides of the fork, inside stanchions, there are coils, either one piece or more. These are what soaks the bumps, potholes, any irregularity. Coil forks are not desirable because:
1. They are heavy. Chunky coils is the main reason of extra weight, compared to air forks. But that can change – will come to that.
2. They are linear. Unlike air shocks, which progressively get harder. This is what I can’t understand in 2022. Cars have variable rate springs for at least 25 years, and that’s what I know. Maybe even much more.
3.Not much adjustable, because you have preset coil spring. It offers some adjustability, to a point, which is most of the time, just to make the fork look more “sophisticated”.
4. They’re noisy, because of 2 things: coils move around, rub or hit inner stanchion walls, or bottom frequently.
5. They bottom out, mostly due to linearity. That means, it compresses all the way down. This is obviously not good for high jumps, for example.
1. They are generally lighter than coil springs, because..it’s an air spring!
2. They don’t grip well as coil forks: they have lot more adjustability, like a proper rebound or negative air. However, they don’t react fast – if you can get the sweet spot right by adjusting them, which looks almost impossible. If you have driven a track car, or a very stiff suspension sports car on rough tarmac at high speed, you’ll understand what I mean: they constantly jump around and lose contact with the road. Someone would go faster with a good sedan then a Ferrari on a very rough road, if all electronic helpers disabled. Same with air forks, for slightly different technical nuances, but you got the point.
3. Expensive to maintain. Most newer shock will need full overhaul in 100 hour periods. 100 hour is nothing. I was riding 3-4 hours a day a year ago! I bought an old Rockshox SID recently, top of the line like 15 years ago, and it has to serviced in 50 hour intervals which is crazy. A complete overhaul kit costs like 70-80$ in my country, minus oil. Of course, these rates are for abusive use, but I doubt I can triple that period even riding half tarmac.
4. Unfortunately, they are not for biketouring, or even longer daily cruise. Unlike coil forks, their failure can be catastrophic: if an o-ring fails, they can bottom out altogether. They’ re obviosly not roadside-repair friendly, too. Super frequent need for maintenance doesn’t help, too.
Why we will be seeing coil forks again ?
Coil forks disappeared long ago, only used on cheap hardtails. Because they were not cool. What made them uncool was race for lightness. With double suspension bikes going mainstream, like downhill bikes, “lightness” lost its popularity, and lightness doesn’t matter when you go downhill – in fact, you’ll want a heavier bike!
As the fork manufacturers already sold 1000$+ air forks to who can afford it, they need to sell anything “new”. People tend to keep their belongings when there is no reason to renew, in sour economical times as now. Now we’ll be reading about lots of good stuff about coil forks, and nobody will question why we left them in the first place, if they were that good…
Soaring material prices is another problem. In order to make a great air fork, you need good quality magnesium and aluminium, also lots of oil and rubber. You’ll also need more energy in the process, for making alloys, hardening or annealing them. Coil forks are heavy anyway, so no one would care about extra 100-200 grams, so they can remove magnesium out of the equation, for instance.
Yet, manufacturers can even make coil forks that are lighter than air forks!
There are 2 interesting things going on: Audi will be replacing steel springs in favor of glass reinforced plastic ones, which are much lighter. They’re made by an Italian company, and if I’m correct, %40 lighter. This can be a big thing in solving heavy coil spring problem, but there is more: ClosedMold Composites patented a technique to make carbon fiber coil springs that is %95 lighter then steel counterparts, and this is madness!
Fox 32 Vanilla R from late 2000’s is only 1900 grams, and typically, coils weigh 300-500 grams. A carbon coil spring means it would be like 15 to 50 grams, which can make that Fox 32 Vanilla fork only 1600 grams, maybe even less!