Automatic Scooters
Wheel Size and Rear Suspension: Choosing a Scooter for Potholes, Speed Bumps and Patched Roads
About 6 minutes to read
Patched strips, shallow holes and raised speed bumps can turn up within a single short trip, and a scooter reacts to each of them according to its wheels and its rear shock. A renter choosing between two bikes may have little more to go on than a glance at the tyres and a feel of the seat. This article explains in plain terms how wheel diameter, tyre sidewall and rear suspension travel affect stability, comfort and ground clearance on broken surfaces. It also shows how to check those things on the actual bike, how to cross a bump or a patch, and what to do after a hard hit. No model figures or measurements are given here; the owner’s manual for the bike and any instructions from the shop take precedence.
How wheel diameter changes the feel of a bump
When a wheel meets a raised edge, such as the lip of a road patch or the start of a speed hump, the edge pushes back along a line running from the contact point towards the axle. A larger-diameter wheel meets the same edge at a gentler angle, so more of that push goes upward and less goes backward against the bike, and the jolt can feel rounder. Holes work the other way round: a larger wheel can bridge a narrow gap that a smaller wheel dips into, while a wide, deep hole can swallow either one.
Diameter is not the whole story. A smaller wheel can make a bike quicker to turn in tight spaces, whereas a larger wheel can feel steadier on a straight run, and frame, weight, tyre and suspension all play a part.
- Wheel sizes can differ between the front and the rear of the same bike, so read both from the tyre sidewall markings and the owner’s manual rather than assuming they match.
- Tyre pressure also changes how a bump feels, and the manufacturer’s label is the place to read it, as covered in Motorbike Tyre Pressure for Rental Riders: Read the Manufacturer Label.
Rear suspension in plain terms: travel, damping, bottoming out and load
Layouts differ: depending on the model, the rear may have one shock on one side or one on each side. Four ideas explain what you feel through the seat.
- Travel is how far the shock can compress before it runs out of room, and more travel can leave more margin for a deep dip.
- Damping controls the movement after a hit. Weak damping can leave the rear bouncing, while damping that is too firm can pass the jolt straight to the rider.
- Bottoming out means the shock has reached the end of its travel, so the hit goes straight through the frame and seat.
- Load matters because a passenger or a heavy bag squeezes the shock before the bump arrives, leaving less travel in hand.
Comparing two scooters for rough roads
Published numbers for wheel size and travel can be measured in different ways, so use this table as a list to compare on real bikes, not as a scoring sheet.
| What to compare | A larger or longer value can mean | A smaller or shorter value can mean |
|---|---|---|
| Wheel diameter | A rounder, gentler hit on edges and a better chance of bridging narrow gaps | A deeper dip into holes, with quicker turning in tight spaces |
| Tyre sidewall height | More air and rubber between the rim and the road | Less cushion, so the rim sits closer to a sharp hit |
| Rear shock travel | More room before the shock bottoms out | Less room, so a deep dip or a loaded bike can use it all |
| Ground clearance | More space for the exhaust, stands and underbody to clear a hump or a ramp | An earlier scrape on a steep ramp or a high hump, particularly once a passenger and bags press the rear down |
A pickup check for wheels, shocks and clearance
These checks need no tools; do them in daylight, engine off.
- Look at each tyre sidewall for cuts, bulges and cracks, and read the size markings at the front and at the rear.
- Ask the shop to demonstrate the rear suspension check with the engine off, both wheels on firm level ground and the bike securely steadied. Do not balance a heavy bike with one hand while pushing on the seat; if you cannot hold it safely, observe and photograph instead. The rear should rise and settle smoothly; a knock or a bounce that keeps going is worth telling the shop about.
- Look at the rear shock body for a wet or oily film, and photograph anything odd.
- Crouch and look under the bike at the exhaust guard, the stands and the underbody; photograph existing scrapes and dents so they are on record before riding away.
- Sit on the seat and confirm that you can steady the bike with a foot down on either side, because a bike you cannot hold at a stop is harder to control after a jolt. Scooter Fit Before Renting: A Stationary Test for Short and Tall Riders goes through a seated check.
Crossing a speed bump or a patched stretch
- Spot the bump early and slow down progressively beforehand, while the bike is upright and heading straight.
- Ease off the brakes just before the front wheel meets the bump, since a front end held down by hard braking has less suspension left to use.
- Cross square-on with straight bars, a relaxed grip and a light, steady throttle, staying seated with both feet on the floorboard or footrests.
- Where a raised edge runs along your line of travel, stay on one side of it if the lane allows; if it has to be crossed, do so closer to a right angle with the bars steady.
- A water-filled patch can hide a deep hole, so slow right down and go around it where traffic allows.
What not to do on broken road surfaces
- Do not brake hard while the wheels are on the bump itself; do the slowing before it.
- Do not stand up off the seat to absorb a hit; stay seated and in control.
- Do not turn any adjuster on the shock, loosen bolts or force a suspension part to change the ride; ask the shop instead.
- Do not swerve around a hole without first looking at the traffic beside and behind you.
If a hard jolt happens mid-ride
- Ease off the throttle and slow down progressively, keeping the bars steady and the bike in control.
- Signal and move to a safe stopping place while the bike can still be controlled, not a traffic lane, then switch the engine off.
- Without dismantling or forcing anything, look at the rims, tyres, rear shock and steering, then photograph any mark or damage before moving the bike.
- If the steering feels off, the bike pulls to one side, a tyre looks soft, a new noise has appeared or you are simply unsure, do not ride on; tell the shop what happened. After a Pothole Hit: Checking Rims, Tyres and Steering Before Riding On lists what to inspect.
- Where someone is injured, or smoke or flames appear, keep everyone well clear of the bike and get emergency help on the way before dealing with the bike.
Questions to ask the shop about wheels and rear suspension
- Of the scooters available for these dates, do any have taller tyre sidewalls, longer rear shock travel or more ground clearance, and could two be compared while parked?
- If a passenger and bags are coming along, does the shop advise any change to the tyres or the rear shock, and who should carry it out?
Thuê xe máy Nguyễn Hà is open 09:00–21:00 daily at Ngõ 5 Nguyễn Văn Cừ, Bồ Đề, Long Biên, Hà Nội (near Gia Lâm bus station). Phone: 0334 699 969.