A tale of 2 forks

2011 Trumph Tiger 800

1951 AJS Model 16

The fork on the right performs better as a suspension device than the one on the left. Technological advances over 60 years give it better damping and a better ability to handle poor road surfaces. The fork on the left will continue to perform for many years without servicing or attention as the makers intended. The fork on the right by the manufacturers own admission is liable to fail at any time after leaving the show room and the all important oil seal that enables it to function correctly is not covered by the manufacturer's warranty. One of the seals on the Triumph failed before it had reached 10k miles. It will cost me about £90 to repair if I remove the fork myself and take it into the dealer, considerably more if I let him do the fork removal.

I wrote to Triumph, asking what the design life of their forks was and this was their response: "However with any man made component there is no expected life cycle as there is always a possibility of a failure. There are many reasons as to why a fork seal may leak due to wear and tear regardless of mileage. Therefore fork seals are not covered under the manufacturers warranty" Note the 'regardless of mileage'. You could drive it out of the showroom brand new and it could be leaking when you get home and it is not covered by warranty. 

Why do the AJS fork seals last for a very long time and the Triumph ones are so poor the manufacturer does not have sufficient confidence in them to include them within its warranty? If anything the seals should be better with advances in materials and design over 60 years. It is nothing at all to do with the seals themselves but their working environment. Notice that there are no exposed fork stanchions on the AJS. The highly polished chrome stanchions are hidden away under protective steel outer covers. It is virtually impossible for dirt,grit and the elements to get in and rip the delicate oil seals. Note on the Triumph the stanchions are out there unprotected, save for a wind deflector, in the open air.

Why are they not protected? Fashion. Years ago race riders stripped off the protective shrouds from their forks to save weight. After all, in a race the bike only has to do 100 miles or so. So to ape the race riders we no longer have decently protected suspension units, even on a so called Adventure bike.