Why are my front suspension forks so stiff? I recently bought a Silverback Stride 29 MD and the forks it came with were the SR Suntour XCE 28. From Day 1 of riding the bike, I noticed that the forks were extremely stiff and I had to exert a lot of energy just to compress the forks. The advertised travel for the forks was 100 mm, however, the forks do not even travel half of the advertised distance. I tried messing around with the preload adjusters but that didn't do much. The forks also do not &quot;Sag&quot; when I sit on the bike but I'm not sure whether &quot;sag&quot; only applies to air forks.
In conclusion, the issue is that the forks feel very stiff and require a lot of energy to compress and do not travel even half the advertised travel distance.
(PS. I weigh 52 kgs if that's any help).
Weighing 52 kg, you are at the lightest end of what might be expected for an adult rider, so you will need the spring to be tuned accordingly. A coil spring has a narrower range of adjustment than an air spring, so if you are too light for the spring, it will not compress enough to be very useful. A lighter spring would be needed.
Reading the generic SR Suntour service manual, it states that your fork is shipped with a medium spring and, aside from tuning the preload:

Two additional spring hardnesses are available for SR SUNTOUR suspension forks - softer and harder than the standard coil spring.

There are three springs available then, to suit riders of different weights, at 52 kg you are too light for the standard spring and would be better served by having a softer spring installed. There are customer service numbers in the service manual too, they could guide you in sourcing a spring as they will be fairly uncommon.
It wouldn't be too difficult for your local bike shop to do the work once the part is sourced, however this raises the question of value. How well will the amended fork perform for the money, and for how long? You might consider putting the money (parts and labour) towards saving for an upgraded fork with an air spring which can be tuned much more precisely and easily; the service manual does give the specs for their air forks for rider weights under 55 kg, so this should not be difficult.