Suspension, wheels and IP protection on electric scooters

Three invisible components determine how a scooter handles rough surfaces and how long it will survive in a wet city: suspension, wheels, and IP protection. Unlike motor or battery, these parameters are rarely advertised with precise numbers — the manufacturer writes “dual” in the suspension field, “10″ pneumatic” in the tyre field, “IP54” in the water-resistance field. Behind those laconic rows hide three engineering decisions that affect comfort, safety, and service life more than an extra 100 W in the motor.

1. Suspension: what absorbs the hit

An 8–11-inch wheel transmits every pothole to the rider through a rigid aluminium frame. The tyre itself damps only high-frequency vibrations (asphalt cracks, joints, fine gravel), while large hits — kerbs, potholes, roots — need actual suspension travel. Modern electric scooters use four approaches:

Coil spring (steel coil spring)

The cheapest and most common type on budget and mid-range models. A steel spring (often with 35–80 mm of travel) works without a fluid damper, so it has soft progression but a noticeable rebound oscillation after a hit.

• Apollo City Pro — one front spring plus two rear swing-arm springs (eRide Hero — Apollo City Pro review).
• Kaabo Mantis 8 — dual C-pattern 50CrVA coil shock-absorbers front and rear (Fluid Free Ride — Mantis 8).
• Apollo Phantom — four spring cartridges (2 front + 2 rear at 45°), with the option to swap springs for the rider’s weight (Fluid Free Ride — Apollo Phantom, Electric Scooter Insider — Apollo Phantom review).

Hydraulic / oil-spring (motorcycle-style)

Spring plus an oil damper with rebound and compression adjustment. Found on performance machines, borrowed directly from motorcycle engineering.

• NAMI Burn-E (and Burn-E 2) — dual adjustable hydraulic-spring suspension with 165 mm of travel; stock KKE dampers originally designed for motorcycles (Fluid Free Ride — NAMI Burn-E, Rider Guide — NAMI Burn-E review).
• Kaabo Wolf King GT Pro — dual moto-shocks front, hydraulic rear, with both ends adjustable (Fluid Free Ride — Wolf King GT review).
• Kaabo Wolf King GTR — hydraulic fork front, 18-position coil-over rear with damping adjustment on both ends (Kaabo — Wolf King GTR Max).
• Dualtron Thunder 3 — swing-arm cartridge suspension with five interchangeable cartridges of different stiffness (Dualtron USA — Thunder 3).

“Hydraulic” in scooter marketing means oil-damped coil (spring with oil damper), not pneumatic (air spring). True air-spring forks do not appear in stock scooters from large OEMs; they are fitted only as aftermarket upgrades on enthusiast builds.

Rubber cartridge (elastomer)

Instead of a spring or oil, solid rubber blocks that compress under impact. Require no maintenance, cannot leak, but have limited travel and rebound depends solely on rubber hardness. This is the engineering signature of Inokim:

• Inokim OXO — rubber cartridges in swing-arms front and rear; each side adjusts between “Low” (stability) and “High” (rough terrain) positions; the manufacturer calls the system OSAP (Ox Suspension Adapter System) (Fluid Free Ride — Inokim OXO review, Electric Scooter Insider — Inokim OXO review).

No suspension — all in the tyres

The cheapest and lightest option: designers omit the component entirely, leaving damping to the pneumatic tyre. This works only with sufficiently large (≥ 8.5″) and soft (40–45 psi) wheels:

• Xiaomi M365 — no mechanical suspension at all, just 8.5″ pneumatic tyres (Rider Guide — Xiaomi M365 review).
• Segway-Ninebot MAX G30 — also suspension-free, relying on 10″ pneumatic self-healing tyres (e-Ride Store — MAX G30 review).
• Segway-Ninebot F40 — stock model with no suspension (Electric Wheelers — F40 review).

For a rider at 80 kg this means: on freshly paved asphalt — comfortable; on cobbles or broken paving — you need to stand on the deck and absorb shocks through your knees.

Two systems instead of one

Premium machines fit independent suspension on both wheels (dual). Budget models fit it only on the rear (Xiaomi Pro 2 / 3, Ninebot E-series have a small spring under the deck). Front-only suspension is rare on adult models: it is more useful than rear-only (since the front wheel hits the obstacle first), but more complex to engineer. In practice, “dual independent” is the gold standard.

2. Wheels: pneumatic, tubeless, honeycomb

Wheel size in electric scooters is not simply “bigger = better” — it is a trade-off between comfort (softer bigger tyre), stability (lower centre of gravity with smaller wheel), mass, and spare-part cost:

• 8″ / 8.5″ — compact commuters (Xiaomi M365, Razor E100).
• 10″ — the universal urban standard (Xiaomi 4 Pro, Segway MAX G30, Apollo City Pro).
• 11″ — performance / off-road (NAMI Burn-E, Dualtron Thunder 3, Wolf King GT).

By construction, tyres divide into three families: pneumatic (air-filled), solid, and honeycomb.

Pneumatic: tubed and tubeless

Inside — air at 35–55 psi (exact value stated by the manufacturer on the tyre sidewall or in the manual). Delivers the best grip, lowest rolling resistance, and softest ride — paying with vulnerability to punctures.

• Tubed — simpler and cheaper, easier to patch, but even a small hole deflates the tyre immediately.
• Tubeless — the tyre seals directly to the rim through a tight rubber bead. Small punctures can be sealed with a plug or the self-sealing compound poured in at assembly.

Self-sealing tubeless tyres are the modern standard for mid-range urban scooters:

• Xiaomi Electric Scooter 4 Pro — 10″ DuraGel self-sealing tubeless. The manufacturer claims pressure stayed above 25 psi after 1,700 km with five 3-mm punctures at 45 psi (Mi Global — Xiaomi Electric Scooter 4 Pro).
• Apollo City / City Pro — 10 × 2.7″ tubeless with an internal self-sealing liner that envelops foreign objects (eRide Hero — City Pro review).
• Segway MAX G30 — 10″ pneumatic self-healing (e-Ride Store — MAX G30).
• NAMI Burn-E — 11″ tubeless (Fluid Free Ride — NAMI Burn-E).
• Dualtron Thunder 3 — 11″ tubeless (Dualtron USA — Thunder 3).

For a general overview of pros and cons see specialist press (Rider Guide — Electric Scooter Tires, Electric Scooter Insider — Tires, Apollo — Complete Guide to Electric Scooter Tires).

Honeycomb / airless (“never-flat”)

Solid or honeycomb tyres eliminate punctures entirely, but pay with three trade-offs: harsher ride (especially without mechanical suspension), higher rolling resistance (–5…–10 % of real range), and additional stress on the deck and frame welds. Ideal for sharing and children’s models; limited comfort for adult commuters.

• Aftermarket honeycomb replacements are popular on Xiaomi M365 (8.5″) and Segway MAX G30 (10 × 2.5″) — fitted by owners tired of weekly city punctures (example aftermarket set).
• Razor E100 — hybrid factory configuration: 8″ pneumatic front + ~125 mm polyurethane solid rear (Razor — E100).
• Lime historically transitioned between generations: early Lime-S and ES4 used primarily solid tyres, while Gen4 moved back to pneumatics (Levy Fleets — Lime Gen4 spec sheet). A classic example of how a sharing operator evolves: initially prioritising zero puncture downtime, then returning to comfort and grip.

“Hybrid” with air channels — a rare solution (e.g. Michelin Tweel-style designs with support spokes instead of solid rubber) (Wikipedia — Airless tyre).

3. IP protection: what IP54, IPX7 and IP68 mean

“Rain equals a controller failure out of warranty” — the most common complaint on cheaper electric scooters. Manufacturers try to address this in the IP rating field, and it pays to read it precisely.

Standard IEC 60529 / EN 60529

Two digits:

• First (0–6) — protection against solid particles and dust.
  • 0 — no protection; 5 — dust-protected (limited ingress, no harm); 6 — fully dust-tight.
• Second (0–8) — protection against water.
  • 4 — splashing from any direction; 5 — water jet from a 6.3 mm nozzle / 30 kPa at 3 m, 12.5 l/min, ≥ 3 min; 7 — brief immersion to 1 m for 30 min; 8 — continuous immersion at depth stated by the manufacturer (usually 1–3 m).

Ratings 9/9K (high-pressure, high-temperature jets) are an extension from DIN 40050-9 / ISO 20653, not part of the IEC 60529 base (Wikipedia — IP code, IEC — IP ratings).

The letter “X” means “not tested”, not “zero”. IPX7 — no dust-protection declaration; IP5X — no water-protection declaration. In demanding conditions (wet sand, fine abrasive) the untested dimension should be read as “potentially worse than zero” (A-M-C — IP65 rating explained).

Real-world devices

• Xiaomi M365 — IP54: dust-protected + splash. The manufacturer states explicitly: “not fully waterproof, do not ride in heavy rain or through puddles” (Rider Guide — M365, eScooterNerds — M365).
• Xiaomi Electric Scooter 4 Pro — IP54 (some revisions claim IP55) (Mi Global — 4 Pro).
• Segway-Ninebot F40 — IPX5 (whole device) (Electric Wheelers — F40).
• Segway-Ninebot MAX G30 — a split declaration: chassis IPX5, but the battery IPX7 (e-Ride Store — MAX G30). This is a common sharing pattern: upgraded protection on the most expensive component (battery) without raising the cost of the entire chassis.
• Lime Gen4 — IP67 for the battery and critical components (Levy Fleets — Lime Gen4, Spokane — Lime Gen 4 operator brief).
• Bird Three — per the manufacturer’s press release, “hermetically sealed industrial-grade IP68 battery” (Bird — Bird Three reveal (PRNewswire), TechCrunch — Bird Three). Note: the primary Bird source refers to the battery, not the entire device; secondary articles sometimes generalise to “IP68 scooter” — that is an inaccuracy.

What an IP rating does not mean

None of the ratings permits:

• Washing the device with a pressure hose (a high-pressure washer can breach IP65 seals).
• Riding in heavy rain for extended periods or through deep puddles — even for sharing-grade IP67/IP68 batteries, the motor-controller-cable body may be rated lower.
• Relying on warranty cover after water damage — the vast majority of manufacturers explicitly exclude “water damage” from warranty regardless of the stated IP.

Segway-Ninebot writes for the F40: “long wading is not recommended, as long wading may cause water ingress and malfunction” and “not advised to ride in the rain” (Electric Wheelers — F40). Xiaomi M365 documentation states the same: “not fully waterproof, riding in heavy rain or through puddles should be avoided” (Rider Guide — M365).

Regulatory: does the law require an IP rating?

The short answer is no:

• EN 17128:2020 (published 21 October 2020, in force 30 April 2021) sets requirements for electrical safety, mechanics, battery/charging, and marking — but public summaries contain no mandatory minimum IP; manufacturers declare IP under IEC 60529 voluntarily (iTeh Standards — EN 17128:2020, en-standard.eu — EN 17128:2020).
• eKFV (Germany, in force 15 June 2019) sets 20 km/h, two independent braking systems, lighting, reflectors, ABE/KBA type-approval, and mandatory insurance — no fixed IP minimum in the text; environmental testing is part of ABE but without a hard threshold (ETSC — Bierbach presentation on eKFV, ATIC TS — eKFV homologation).

At the market level, IP54 became the de facto standard for commuter devices in 2019–2021 (driven by the Xiaomi M365), and IP67/IP68 the standard for sharing, where scooters sleep outside and are hosed down daily at the operator’s depot. This matches the industry-maturity timeline (details in the article “Chronology: 2020–present”).

4. Owner checklist

Seven points to examine when evaluating chassis components:

1. Suspension type on each wheel separately — coil spring / hydraulic / rubber / none — and whether it is adjustable.
2. Suspension travel (mm) — for off-road this is the key number (NAMI Burn-E: 165 mm; typical coil commuter: 30–50 mm).
3. Tyre type — pneumatic tubeless self-sealing? Tubed? Honeycomb? Does it suit the scenario (city with puddles vs old cobblestones vs sharing)?
4. Tyre size — under 8.5″ for an adult with no suspension equals constant discomfort; ≥ 10″ comfortable on asphalt; 11″ comfortable on dirt too.
5. IP rating — and of what exactly — IP54 for the whole device ≠ IPX7 for the battery. Read precisely what the manufacturer claims.
6. Does the warranty exclude water damage — for most it does; this means IP is a rated resistance, not a licence to ride through downpours.
7. Tubeless self-sealing vs aftermarket honeycomb — trade-off between comfort and puncture-proof; for urban tile-and-broken-glass environments honeycomb often justifies the harsher ride.

These three components, alongside motors, battery, and brakes, form the complete engineering circuit of an electric scooter. Subsequent guide sections cover how to choose a scooter for your scenario, safety and traffic rules, maintenance, and storage.