Maximum differentiation
In the 100 to 170 millimetre travel range alone, at least the major suspension fork manufacturers, such as Fox and Rockshox, have five different top models with their own casting in their range. For the 100 millimetre range there is the Fox 32 Stepcast and the Rockshox SID SL, for travel up to 120 millimetres there is the Fox 34 Stepcast and Rockshox SID. This is followed by the Fox 34 and Rockshox Pike with 140 millimetres, and the Fox 36 and Rockshox Lyrik serve the range up to 160 millimetres. At the top end, the new suspension forks with 38 mm stanchions complete the range of single crown forks. Fox 38 and Rockshox ZEB are the new top dogs for enduro use.
Suspension forks: 38 mm stanchions replace the thin castings
The other manufacturers are also following the trend and differentiating more and more. The overlap of the spring travel is thus kept as small as possible and the respective fork is customised as much as possible to the intended area of use. In addition, with the introduction of thicker 38 mm stanchions, everything has moved down a category. Until recently, the Fox 36 and the Rockshox Lyrik symbolised hard enduro use, but now they are poaching in the all-mountain segment with reduced suspension travel. With this development, manufacturers are of course also responding to the increased demands and loads that a suspension fork in modern MTBs or E-MTBs is confronted with. The bikes are becoming more downhill-heavy and potent across the board and are pushing the limits of what is rideable. And even without the additional weight of the battery and motor, the average German now weighs almost 90 kilos. It is therefore hardly surprising that fork manufacturers are responding with stiffer and generally heavier forks. We spoke to Elmar Keineke, Fox Marketing Manager.
BIKE: Are 38 mm stanchions really necessary with 170 millimetres of travel?
Elmar Keineke: The thicker diameter is not essential, but it is definitely an advantage. The larger cross-section not only increases the stiffness and precision of the suspension fork, but also its function. As the tube pairs can move better parallel to each other and tilt less, stiffer forks respond more sensitively under load. Our Fox 38 was developed to deliver the best performance even under competition conditions. Achieving more stiffness with thinner stanchions would also be at the expense of weight.
So does it generally apply: the stiffer, the better?
A high level of stiffness helps the components, which should be able to move in relation to each other even under load. However, a suspension fork does not have to be stiff in all directions. The torsional stiffness, for example, can be somewhat lower, which makes the suspension fork more forgiving. With many stiffnesses, there is a sweet spot between too soft and too stiff.
Is the extra weight of a thick, stiff suspension fork also useful for light riders?
As a stiffer chassis works better, lighter riders also benefit from it. Lightweight riders also had a say in the development of the new suspension fork platform with thicker 38 mm stanchions. In the many tests, the thicker castings ultimately prevailed for everyone. Due to the often very long stages in enduro races, the function of a suspension fork is much more important than a few grams of extra weight.
What about durability? Can thicker suspension forks also score points here or does the load on the frame increase?
Enduro frames are constantly evolving along with suspension forks and have gained weight over the years. Modern frames are therefore also designed to withstand the load of stiff and long suspension forks. In terms of the durability of the suspension forks themselves, thicker stanchions have a larger contact surface on the bushings, which reduces the pressure, but also allows more dirt and dust to adhere. Therefore, we do not have different maintenance intervals for a thin Cross Country or thick Enduro fork. Experience has also not revealed any real differences. However, for perfect function, it is always advisable to keep maintenance intervals as short as possible.
Especially in the long-stroke range, a few suppliers are once again using a steel spring instead of air. Will we see a revival of coil in the future?
Modern air forks now respond so well thanks to sophisticated negative chambers that it is difficult to feel any difference to a steel suspension fork. In addition, air forks can be tuned across a very wide range without any effort. If the spring rate of a coil fork does not fit, the only solution is to replace the spring. This makes handling unnecessarily difficult for both the end customer and the dealer.
Conclusion from Peter Nilges, BIKE test manager
Our laboratory and practical tests clearly show that brake stiffness in particular benefits significantly from the thicker stanchions on suspension forks. Fox, Rockshox and SR Suntour rely on massive 38-millimetre stanchions for their long-travel forks, thereby optimising stiffness. Compared to suspension forks with 36 or even 35 mm stanchions, the stiffness is 25 to 50 per cent higher with the same suspension travel.
