I got a bit of a shock when I found that the shock absorber on my Boardman mountain bike would cost around £350 to replace. Even with a discount it’s being offered by a big supplier, Chain Reaction Cycles, for £279. How can they be so expensive? All they consist of is a tube containing oil which a plunger moves up and down inside. This is the damper which controls the movement of the shock and stops it from bouncing up and down like a rubber ball. Surrounding this is the air chamber which you fill through the type of valve a car tyre has. This air is pressurised when the shock compresses to act as a spring. Such a simple system and fairly easy to work on. Even so a professional rebuild might cost £99. A rebuild will never take an hour and with practice might take more like 15 minutes. So why am I concerned? Well the Boardman’s shock has always leaked a little air but the leak has got much worse recently, after 3 years. Today I removed the offending item and took it apart as you can see in the picture at the top. I just need to replace the rubber rings which act as seals and reassemble it. I’ve ordered the seals for £17. The damping is still working perfectly so I won’t open the damper to replace the oil and seals within. In the meantime I’ve fitted an old shock from a previous bike which has the same dimensions. What matters is the length and amount by which it can be compressed. So I’ve replaced a 3 year old Rockshox Monarch RT with a 20 year old Rockshox SID and was curious to see what 20 years of development has done to suspension.
The ground was wet so once again Healey Nab seemed the best choice and I rode 3 laps. It also helps to use a familiar proving ground to compare different components. At first I felt that the SID was stiffer, especially over small bumps, with a noticeable clunk as it returned to full extension. This noise may just have been caused by a lack of air in the second, negative air chamber. I remembered that this chamber leaked so didn’t add any air. It’s not an essential part of the shock, just more of a luxury. The Monarch fills it’s own negative chamber and this may well be where the air is leaking from. I’ll probably never know, since replacing all the seals should solve the problem. Riding on the road I was sure that the movement was stiffer at the start but it was responding well enough to bigger bumps. On the trails all went well. I didn’t think I was getting any less grip from the rear wheel and even found one section of trail where the SID was doing better. I approached the new jump section a short way down the main downhill and stood up to absorb the first big hump, allowing the bike to rise up under me, keeping the wheels on the ground by extending my legs on the back side of the jump. Next comes a flat topped “Tabletop”. With the Monarch shock I’ve always felt the back wheel popping up, causing me to nose dive. I assumed that the jump was just badly shaped but after 3 tries today I’m now thinking that I haven’t had the damping set high enough on the Monarch. I’ve hit the jump, compressing the shock which has then sprung back too quickly, bouncing the back wheel upwards. It’s good to have learned something but what I learned most was that a 20 year old shock still works very well. Yes, the newer shock feels plusher but in terms of grip there is no difference. The bike industry seems to rely on convincing us that only the latest things are any good but I was having a blast riding this old shock. The slippery trails were great fun to slide around and I found the limit plenty of times. As I’ve no doubt said before, the limit is my special place, which I like to visit as often as possible.
The hero of the hour. A 20 year old shock absorber. It has to go with the writing upside down on this bike, which it was never intended for.
I can see from my Strava record that my 3 fastest times this year, around the whole red graded circuit, were set, not on my modern bike but on my two 15 year old Whytes. Fastest was the JW4 and second and third were on the PRST4. Are we really improving things?
Mountainbiker 