Aairsk X5 Fat Tyre Electric Bike - 48V 15Ah

The Aairsk X5 is a fat-tyre electric bike on 20 x 4.0-inch tyres with a 48V 15Ah battery and front suspension, built for stability across mixed terrain. £499.99 with free UK delivery.

Held in UK stock, so there's no import wait and no customs charge when it arrives — typically 3–5 working days, often faster.

How fast does it go?

The X5 has a selectable power specification, and this is the most important thing to understand before buying:

• Standard setting: 25km/h (15.5mph) — the UK legal assistance limit for road use
• Unlocked setting: up to 40km/h (25mph) — private land only

The supplier lists a switchable 250W/500W motor specification alongside those speeds.

How far will it go on a charge?

The 48V 15Ah battery gives an estimated 30–40km (19–25 miles) on throttle alone, or 40–60km (25–37 miles) with pedal assist.

Fat tyres carry a small range penalty compared with narrow ones because of the extra rolling resistance — that's the trade for the grip. Hills, cold weather, tyre pressure and rider weight all reduce range further, so plan against the lower figure. A full charge takes around 5–6 hours.

How long will the battery last?

Expect several hundred full charge cycles — typically around 500–800 for a lithium-ion pack — before capacity noticeably drops, which is several years for most riders. Charge it indoors where you can, and avoid leaving it flat or sitting at 100% for weeks at a time.

What are fat tyres actually for?

A 20 x 4.0-inch tyre puts far more rubber on the ground than a standard bike tyre and can be run at lower pressure. In practice that means noticeably better grip on wet roads, loose gravel, sand, grass, mud and snow, plus a cushioned ride that partly compensates for having only front suspension.

The trade-offs are weight, a bit more effort to pedal unassisted, and slightly reduced range. If most of your riding is on smooth tarmac, a standard tyre is the better choice — our fat tyre vs standard comparison covers this properly.

Road use and the 500W setting

In its 250W / 25km/h configuration, the X5 matches the UK EAPC specification for riding on public roads and cycle paths without registration, tax, insurance or a licence.

The 500W / 40km/h unlocked configuration is not road legal and should only be used on private land with the landowner's permission. Selecting the higher setting takes the bike outside EAPC rules regardless of what mode you switch back to afterwards.

Check the current GOV.UK EAPC rules before riding on public roads, and see our guide on whether a higher-wattage e-bike is legal if limited to 250W.

Specifications

Range and speed figures are supplier estimates rather than guarantees.

Delivery and returns

• Free UK mainland delivery from UK stock — typically 3–5 working days, often faster.
• 12-month warranty.
• 14-day right to cancel under the Consumer Contracts Regulations 2013, plus your full rights under the Consumer Rights Act 2015.
• Sold by Horizon and Co Solutions Ltd, a UK registered company (No. 16942003, England and Wales).

Compare before you buy

Compare the X5 against the Hidoes HD-B6 Mini, HD-F3 and HD-F3 Pro in our best fat tyre electric bikes UK 2026 round-up, or see the winter riding guide for why fat tyres help in wet weather.