Stock Surron suspension is tuned for a low sticker price, not for a 180-pound rider hitting braking bumps at speed. The fork is undersprung, the shock is underdamped, and both run through their travel long before the trail gets interesting. If you've already dialed in brakes and tires and the bike still feels vague or harsh, suspension is next — and it's the single upgrade that changes how a Surron rides more than anything else you can bolt on.
This guide walks through what actually needs to change, compares the three suspension brands ThrottleCo carries for the Surron platform — RFloXa, Sirris, and EXT — with real specs and pricing, and covers what to expect during install.
Where to Start: Sag, Spring Rate, and What "Upgrade" Actually Means
Before spending a dollar on new suspension, set sag on what you have. Static sag should land around 25–30% of total travel with you sitting on the bike in riding gear. If the stock fork and shock can't get there without bottoming or topping out, that's your sign the spring rate — not just the damping — is wrong for your weight, and no amount of clicker adjustment fixes a spring rate problem.
Every aftermarket fork and shock in this guide is sold by spring/travel option rather than one-size-fits-all, which is the biggest functional difference from stock. Buying the correct spring rate for your weight up front matters more than which brand you pick.
Front Fork Options: RFloXa vs. Sirris vs. EXT
The front fork controls how the bike tracks through braking bumps and how confident you feel diving into corners. Here's how the three options ThrottleCo stocks for Surron compare:
| Fork | Price | Travel | Spring Options | Best For |
|---|---|---|---|---|
| RFloXa Hawk31 Pro | $899 | 203–228mm | 45–60 lb, incl. progressive | Budget-minded riders who still want adjustable damping |
| RFloXa Hawk31 Max Inverted Fork & Triple-Clamp Kit | $999 | 203–228mm | 45–60 lb | Riders who also want a triple clamp refresh in one purchase |
| Sirris F43 CMX | $2,250 | Race-spec (oversized 43mm chassis) | Weight-class tuned: Medium 140–180 lb, Heavy 180–220 lb | Riders who want race-shop-level tune and don't mind the price |
| EXT Ferro E-MX | $1,895 | Dual-crown inverted, MX-spec travel | Air spring, tunable | Riders who want true motocross-grade damping and air-spring adjustability |
RFloXa is the value play here — the Hawk31 Pro fork gets you real adjustable damping and a proper travel bump for under $900, and it's the fork most riders should start with unless they're already racing. Sirris and EXT step into a different tier: the Sirris F43 CMX is weight-class tuned rather than one spring for everyone, which matters if you're well outside the 140–180 lb "average" bracket most stock-replacement forks assume. The EXT Ferro E-MX brings genuine motocross air-spring tech to the platform, which is the fork to pick if you're chasing the most tunable, race-proven damping curve regardless of cost.
Rear Shock Options: Budget to Race-Spec
The rear shock matters just as much as the fork, and it's often the cheaper half of a suspension upgrade to get right. The RFloXa RAB50RC reservoir shock is the entry point at $150 — a real reservoir shock with 450 lb or 550 lb spring options, and by far the best dollar-for-dollar improvement over stock available on this platform. Step up to the Sirris R46 at $899 and you get five tune levels (Trail Light through Trail XX Heavy) so the valving matches your weight and riding style, not just the spring. At the top, the EXT Arma MX ($1,175, spring rates from 400–600 lb) is the shock EXT runs on their own personal bikes — the kind of damping quality that's genuinely hard to feel the ceiling of on a trail ride.
Matching Front and Rear (Don't Mismatch Your Suspension)
Upgrading just the fork or just the shock leaves the other end of the bike working against the improvement — a plush new fork paired with a harsh stock shock just moves the weak link to the rear, and vice versa. If budget allows, buy the fork and shock together. ThrottleCo bundles the RFloXa Hawk 31 Max fork with the RAB50RC rear shock at $1,099 for a front-to-back matched setup, and EXT offers the Ferro fork and Arma MX shock as a combo set at a discount versus buying each separately. Matched suspension is the difference between a bike that feels balanced through a whole trail and one that feels good in front and vague in back (or the reverse).
What to Expect During Install
All of the forks and shocks above are designed as direct bolt-on replacements for stock Surron mounting points — no frame modification required. That said, a few things to plan for:
- Basic hand tools and a torque wrench are enough for shock swaps; fork swaps on inverted units may require removing the front wheel, brake caliper, and fender, so budget more time.
- Triple clamp bore diameter matters on some fork upgrades — confirm your stem size before ordering if you're not buying a fork/clamp kit together.
- New suspension needs a proper break-in period. Don't judge final feel off the first ride; damping oil and seals typically settle in over the first several hours.
- Re-check sag after installation and again after the break-in period — spring rate that felt right on paper can still need a preload adjustment once you're actually riding on it.
If you're not sure which combination fits your weight, riding style, and budget, reach out before you order — we'd rather help you pick the right spring rate than deal with a return. Shop the full Surron parts catalog at throttleco.store, or browse suspension by platform to find your exact fitment.
