Q: I have an all-mountain bike with 150mm of travel in the rear and a 160mm fork. The bike came with a RockShox Lyrik fork with 35mm stanchions, but I am thinking about swapping those out for either a RockShox ZEB or DVO Onyx 38 with 38mm stanchions. What are the pros and cons of switching to a larger-diameter fork? Will it be worth it?
David Baldacci
Encinitas, California
A: Switching to a larger-diameter fork or sticking with the stock 35mm option depends on a few factors, mainly your riding aggressiveness and the type of terrain you typically find yourself on.
The main benefit to moving to a larger-diameter fork is increased stiffness from the front end and improved steering precision, which is particularly noticeable on rough, high-speed and technical descents where you’re pushing the limits of the bike.
The bigger 38mm stanchions help provide additional rigidity and reduce flex that many riders say help improve the bike’s stability and predictability when plowing through chunky and blown-out sections of trail and pushing through corners, as well as better performance on big jumps, drops, and other big impacts.
Some larger-diameter forks also feature air shafts and dampers that have a bias towards rough and rowdy descents and big hits, further helping with stability and predictability when you’re pushing the limits of your 150mm all-mountain bike.
That isn’t to say that forks with larger stanchions don’t also have their drawbacks. The most obvious one is added weight.
Forks with 38mm stanchions require more material to manufacture than 35mm/36mm ones, so naturally they will weigh more and won’t be optimal if you’re trying to maximize climbing performance or keep your bike as lightweight as possible.
It doesn’t sound like you are, but it’s still a consideration. Another potential drawback is the extra stiffness and reduced compliance.
While beneficial on rough and rowdy trails, some riders feel they can be overly rigid on smoother and less demanding ones, where extra stiffness is not always a good thing. Some riders also feel more fatigue and arm pump on long, sustained, and flowy descents since more feedback is translated through the rider’s hands and arms.
At the end of the day, it really comes down to personal preference.
If you’re consistently riding rough, technical, high-speed trails, or even occasionally getting between the tape at an enduro race and aren’t as focused on climbing performance, a 38mm fork could bring some noticeable benefits.
However, if you want to maintain more of a well-rounded platform that caters to a wider variety of terrain/trails, sticking with the 35mm/36mm one might be the better choice.
If you’re able to buy the bigger fork without selling your current one, that will give you the best of both worlds and let you switch back and forth to feel the difference for yourself before committing to one.