The stock MATE X suspension fork may be functional, but it has shortcomings. Depending on how you ride and how much you weigh, you may want to look into upgrading it. It’s a relatively easy operation, but there are some things to keep in mind.

The main problem with the stock MATE X front suspension fork:

The original MATE X front fork (MOZO FATMAN-26-20) is a spring-coil suspension with two dials on top of each “leg”. One dial (Preload) controls how much the spring moves under pressure. The other dial (Lockout) stops movement, which you might prefer in urban/street situations.

I chose the MATE X because I’m a hefty lad. When I dropped off a curb or went over a pothole, I would hear a loud metallic “CLUNK” from one or both suspensions, followed by a jarring shock up my spine and/or arms. It does not support my weight, and even if I weighed 20 kilos less, I would still have issues riding off-road. I tried tightening the spring, but it seemed like it could be turned forever, giving off an occasional “click” then going soft again. I was concerned I was stripping the thread of some internal screw.

The MATE X is advertised to support a rider of up to 140kg. The suspensions do not live up to that claim. If you build a spring-coil suspension that works for people who weigh between 60-90kg, you’re going to sacrifice support for anyone above that. Mechanical springs would need to be longer and have more space to compress (this range of movement, or distance, is called the travel). You could also make a fork that has stiffer springs while sacrificing support for people who weigh less.

The alternative: an air suspension fork

Air forks have been around for decades for mountain bikers, but for fat bikes like the MATE X, they’ve only become widely available over the past 3 years, especially after a manufacturer called Himalo started making them. Air forks tolerate a much wider range of rider weight and riding parameters.

Air forks come in many colors, brands, and the mechanisms can be called air fork, oil-air fork, air-spring etc. but they are essentially similar enough to not be concerned about it. It’s all an improvement over the stock fork no matter what you choose, or what the manufacturer calls it. While all air forks come with an air-valve and compression-adjustment, they might also come with or without rebound adjustment, and a handy lockout switch that can be mounted to your handlebars.

Specifically for the MATE X or similar , you need to keep some things in mind and make some decisions before upgrading.

The single crown fork resembles the stock fork, and more often comes with rebound adjustment knob at the bottom of the right stanchion. This is a great upgrade, and was my first fork replacement.

What i did wrong was to cut the steerer tube to fit my folding handle bars, which made it impractical to change the handle bars to BMX bars later.

The double-crown fork was my second fork upgrade. These forks were developed for downhill mountainbiking, and can easily be identified by the “legs” (stanchions) continuing to the top of the frame. It’s generally considered a stronger and safer fork for more demanding rides. While it looks cool and is reminiscent of motorcycles, there are several factors to be aware of.

• The additional hardware means more weight, about 500g.
• The stanchions limit how far you can rotate the handlebars when turning (not really a problem when riding, but maneuvering the bike in a tight spot can be a pain)

The stock MATE X fork has a screw-in topcap or headcap that pulls the steerer tube up through the folding handlebar loader. Replacement forks won’t have a thread inside the tube, so you’ll need a top cap and a star nut. These in turn require special tools, or a home-made hack to insert.

Last notes

Installing a fork is not something we’ll get into here. However, any bike mechanic worth his name should know how to do this, especially if you bring him the parts he needs. You can certainly find YouTube videos on the subject if you wish to do it yourself. Just remember to be especially careful and patient with the bearings.

Setting up the fork to fit your riding style and weight is also a very individual thing, but you should definitely look into how to set the sag, and remember that unlike mountain bikes and mountain bikers, you’re probably going to spend more time in the saddle, and will need to set the sag based on that, rather than standing up on the pedals.

If you plan to keep your folding handle bars, you’ll need to cut the steerer tube down to the exact same length as the original fork . That will give you issues if you ever wish to upgrade the MATE X folding handlebars to BMX handlebars in future, as you’ll need a BMX top-loader that is thin enough to grip what little of the steerer tube that sticks out from the top of the frame. Also, if you feel the BMX handlebars are too low for you, the short steerer tube means you can’t just insert spacers to raise the handlebars. Therefore I highly recommend upgrading your fork and handlebars at the same time,. However, it is possible to get a steerer tube or fork stem extender – I have never used one, so can’t advise. You can also see if you can find additional spacer rings to insert between the top of the frame and the folding bar. That would allow you to have a longer steerer tube while keeping the folding bars, but I am uncertain of the correct diameter.

The front brake cable may be too short to go in the wire harness if your new fork is any longer than the original. Be especially aware of this when folding the handlebars down, so you don’t tear the brake cable.

You’ll need a special shock-pump to put air in the fork. These usually have special valves to stop air rushing out when you attach and remove the pump, and unlike regular bicycle pumps, they can add/remove air pressure in very small increments. A regular pump can also damage the fork’s air chamber or seals by adding too much pressure too fast.

Here are the specs you’ll need to know:

• Fork Width (drop-out): 135 mm
• For 4″ wide tires
• Crown Race: 30.0mm (Straight, not tapered)
• Stanchion Size: 34mm
• Travel: between 85-100 (Single Crown) / between 100-120mm (Double Crown)
• Hub-axel Ø10mm (standard size)
• Stem (steerer tube) Ø28.6mm
• Disc brake mount: 74mm