Air and Gas Shocks Totally Change the Surron LBX

What is a ‘shock’?

The rear suspension, also known as the ‘shock’ on a Surron LBX is a spring that allows the rear wheel to travel up and down to maintain better ground contact, a smoother ride, and more controllability. This is achieved through pivoting points on the swing arm and frame that are connected to an adjustable spring mechanism.

This spring mechanism is usually put into two categories: air springs or coil springs. Both work with similar principles, and both dampen, or smooth, the bumps during a ride. A good rear suspension will soak up the smaller bumps and also take the hard hits on all types of landings – the good and the bad! The stock Surron LBX has a coil spring, otherwise known as coil over shock. But is that the best solution?

The biggest difference between air and coil is exactly that. The shock compresses when bumps are hit. In an air shock, air inside the cylinder compresses vs an external spring compressing on a coil shock. The rest works with similar principles.

Shock Basics

coil shock diagram
Coil Shock
air shock diagram
Air Shock

Eye to eye: Distance between the two bolts that hold the shock to the frame

Stroke length: How far the shock can compress

Leverage ratio: A measurement of how far the rear wheel will travel vs movement of the shock. This could be described as a 2:1. For example, for every 2 inches of wheel travel, the shock will compress 1 inch. 

Piggyback reservoir: The additional reservoir found on some shocks containing additional gas, air, or oil.

Adjustments: Found on some shocks, the adjustments are similar to the forks – some have rebound, compression, preload and damping settings. 

Spring rate: A measurement of pounds of force needed to compress the spring one inch. For example, The Vonkat TENfive Rear Shock this shock comes either in 525 lbs/in or 450 lbs/in, meaning depending on which spring you order, it will either take 525 pounds or 450 pounds of force to compress the spring one inch. 

Linear rate: The pounds of force on the spring are linear, meaning it will take 450 pounds of force to compress the spring the first inch, another 450 pounds of force to compress the second inch, and so on. This gives a standard, predictable rate of response.

Progressive rate: By contrast to a linear setup, with a progressive spring rate the force required to compress the shock must get progressively greater to continue to compress the shock. It might take 450 pounds for the first inch, then 1,200 pounds for the second inch. That’s an exaggerated example, but you get the idea. This gives a stiffer feel towards the bottom of travel. 

What Rear Suspension Does Surron Have From The Factory?

Boasting a multi-link rear suspension that is very similar to gas-powered dirt bikes, the 2023 model Surron X arrives with either a KKE or DNM Shock with TR Suspension link system – all coil setups which are adjustable for both compression and rebound (Surron).

A quick Google of Surron rear suspension will instantly pull up a multitude of pages exclaiming that the stock suspension sucks, and that you must upgrade instantly. But is it necessary? It depends on your riding style, and why you think you need to upgrade. It also depends on your weight. Yep, being politically correct, let’s just say, the spring on the stock Surron is set at ‘standard’. If you’re anything except ‘standard’, you will need to look at a different spring rate. Back to your riding style, if you’re spending weekends at the track blitzing the whoops and landing sky-high jumps, your shocks won’t know what’s hit them. Literally. If you love meandering forest tracks and commuting to work, then the stock shocks will probably be adequate. 

However, if you want that plush yet planted feeling, as well as the ability to maintain traction through the corners more predictably, with further ability to adjust, then it also might be time to upgrade. My suggestion – if you haven’t done so already, look at upgrading the front forks first.

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Are Air Shocks Better Than Regular Shocks?

Whenever you look at upgrading, you need to ask yourself the question of how much do you change things? Is now the time to replace the stock coil shock with an air shock? The answer might surprise you. 

Pros and Cons: Air Shocks

The first and most noticeable pro the air shock provides is the weight – it is physically lighter. While this might not be the first thing you think about, on a light e-moto, any added weight is a large percentage. 

It also has a more progressive feel due to the nature of compressed air. This allows for a smooth ride over the smaller, chattery bumps and also is great for large landings. The fact that it is air that cushions you, means you can simply add more or take air away to change the complete feel. It is almost infinitely adjustable with ease. 

But with the need to hold air in a chamber comes many more parts, and parts that could potentially fail or leak. Moving parts together creates something called stiction. That is the resistance you first feel to get things moving. Higher-end shocks use special lubrication between parts that limit stiction, but generally speaking, this issue is more pronounced with air coils. With more moving intricate parts, air shocks are generally worse on the wallet as well.

Another issue that can arise is heat. The oil inside the shock can heat up, and well, think of honey – thick and gooey at room temperature, but if you pop it in the microwave, it turns into a runny liquid. The same applies to oil when heated, and provides much less damping properties. 

Pros and Cons: Coil Shocks

Opposite to air shocks, the coil shock is heavier, and you’ll need to weigh up (bad pun, sorry!) if the added performance is better than an increase in weight. So is it better performance? The feel from a coil shock is typically more linear and starts working instantly with much less stiction. The only seals needed are within the damper, which means fewer parts that could leak and fail. Coil springs also handle the heat much better. 

Coil Shock on the Surron
Coil Shock on the Surron

However, the coil doesn’t have the same ability with adjustments. If you need a different spring rate, you need a new spring – you can’t just add air! Chances are the spring that comes with your stock e-moto won’t be exactly perfect for you, and that would be a part worth upgrading sooner rather than later. Coil springs are usually cheaper, although some higher-end models which feature titanium light weight material would be of a similar pricing to the air shocks. 

When Do You Upgrade? 

Before you do anything else, make sure you tune your own suspension and have it set to your liking. If you do nothing else, at least set the sag. The sag is how much the suspension drops when you sit on your Surron, riding gear and all. This should be done to both the front and the rear suspension.

Read more on the forks here

Setting the sag on the shock is relatively simple: Place your Surron LBX on a stand to remove all the weight from the swing arm. Measure from the axle vertically to a fixed point on the fairings or seat – any reference point and remember what you used. Next, you may need a friend to help, put on all your riding gear including a helmet, and sit on your e-moto again. Measure from the axle to the same reference point. Note this distance. The difference between those figures should be between 20% to 30%. If not, you need to adjust the preload to change the sag. Read this article for in-depth information. If you’re maxing out the preload settings, then it might be time to start looking at a different shock, or at least a different spring if you’re still on the stock setup. 

Do You Upgrade The Front or Rear Suspension First?

You don’t just ride a dirtbike, you’re at one with your dirtbike. Anyone who has been so in tune with their ride understands this concept. But, if something’s just not right, something’s a little out of whack, it’s hard to get in the zone. Ideally, you would want to change both front and rear suspension at a similar time. I say similar, as I always recommend upgrading one part first, so you know what’s causing your Surron to improve, or worsen and it gives you a better understanding of what each component does. 

Suspension is a dark art. Adjust here, and something changes over there! The front and the rear work in harmony, as do new tires, different sprocket sizes, and so on. In particular, with the lightness and power of the Surron LBX, the front forks are prone to more failure and bottoming out before the shocks, and for that reason, it would be advisable to upgrade your forks before shocks. 

What Do You Upgrade Your Surron Shock To? 

The biggest factor when deciding to upgrade your suspension is what will actually fit on your e-moto. Unlike the forks, where there are many more options, the rear shock needs to fit into the cavity of the frame. This might instantly rule out options, and it would be wise to double-check the measurements of your e-moto before making any online purchase. If you’re not sure at any stage, check with the company. GritShift has a team on standby if you need to discuss parts specifics to ensure the right fit for your dirtbike.

So, do you upgrade to a coil or air shock? Personally, I like the coil shock – I’ve always run them on my dirtbikes. My downhill bikes, on the other hand, have air shocks. The weight saving is great, but it’s a pain when they start leaking. Call me lazy, but I like the least amount of work possible prior to riding! Once you set your rear suspension correctly, the coil never changes! I also like the feel of the coil shock, with its linear feel. As you can see, it comes down to a personal opinion. Cost and fitment aside, you need to like the feel and it needs to fit the terrain you’re riding on.

Do you share your Surron LBX with your significant other? If so, are you similar in weight, or would you like the flexibility an air shock provides? Just an out-there thought… However, a simple way also to solve that problem is just to buy two Surrons! As always, the GritShift team is here to help and get your e-moto fitting like a glove. 

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