Wheels change how a skateboard feels more than almost any other part. The same deck can feel like a street setup or a cruiser depending on what you bolt on. Yet wheels are described with a confusing mix of numbers: diameter in millimeters, durometer on an “A” or “B” scale, contact patch, and vague words like “street” or “park.” This guide explains what each number actually does so you can pick wheels that match how and where you skate.
The Two Numbers That Matter Most: Size and Hardness
Every skateboard wheel is defined primarily by diameter (how tall it is) and durometer (how hard the urethane is). Get these two right for your skating and everything else is fine-tuning.
Diameter (Millimeters)
Diameter is measured in mm and typically ranges from about 50mm to 60mm+ for standard skateboards.
- 50–53mm: Small and light. Slower to accelerate and lower to the ground, but quick to spin for flip tricks. Popular with technical street skaters. Below 50mm you start risking rough-ground hang-ups.
- 54–56mm: The all-around range. A good default for street, park, and mixed skating. If you are unsure, start here — 54mm is the most common first choice.
- 57–60mm: Faster top speed and better roll over cracks and rough ground. Favored for transition, bowls, and ramps. Heavier and a touch more sluggish for flips.
- 60mm+: Cruiser and longboard territory. Great for getting around, not ideal for tricks, and often need riser pads to prevent wheel bite.
Durometer (Hardness)
Durometer is measured on a scale followed by a letter, usually “A.” Higher number means harder.
- 99a and up (and the 83b–84b range): Hard wheels. Fast and slidey on smooth surfaces like skateparks and indoor floors. They transmit every pebble and crack, so rough streets feel harsh. This is the standard street and park choice.
- 95a–98a: Slightly softer. A little more grip and a little less buzz on imperfect ground while still being fine for tricks. A sensible pick if your local spots are not glass-smooth.
- 90a–94a: Noticeably softer. Grippy, comfortable on rough ground, not ideal for power slides. A “rough street” trick-capable option.
- 78a–87a: Soft cruiser wheels. They soak up cracks, gravel, and expansion joints and roll almost silently. Meant for transportation, not flip tricks.
Note the “b” scale: it exists because the “a” scale compresses near the top. An 83b wheel is roughly equivalent to about 88a — harder than a 99a. If you see a “b” durometer, mentally add about five points and compare on the “a” scale.
Contact Patch and Wheel Shape
The contact patch is how much urethane actually touches the ground. A wider contact patch gives more grip and stability (good for transition and fast lines); a narrower one slides more easily and feels quicker underfoot (favored by tech street skaters). Wheel profile — rounded vs. more square edges — affects how predictably the wheel breaks into a slide. Most people never need to think about this until they have a specific complaint, like “my wheels grip up when I try to slide.”
Matching Wheels to How You Skate
Street and Technical Skating
50–54mm, 99a or harder (or 83b–84b). Light, quick to flip, slides predictably on ledges and smooth ground.
Skatepark and Transition
54–58mm, 99a or harder. A bit more diameter for speed and roll, still hard for pumping and grinding.
Rough Streets but Still Want Tricks
54–56mm, 95a–97a. A compromise that takes the sting out of bad pavement without turning your board into a cruiser.
Cruising and Commuting
56–60mm, 78a–87a. Prioritize roll and comfort. Expect wheel bite on a standard popsicle deck unless you add risers or run looser, taller trucks.
Practical Tips When You Buy and Install
- Replace wheels in sets of four. Mixing old and new, or two hardnesses, makes the board track unevenly.
- Rotate your wheels when you notice one-sided coning (wheels wearing into a cone shape), which happens from repeated turning and sliding one way. Our guide on replacing skateboard wheels walks through the process.
- Reuse or replace bearings deliberately. New wheels do not come with bearings. If you reuse yours, it is a good moment to clean and lubricate them.
- Check for wheel bite after installing bigger wheels by leaning hard into a turn while stationary. If the wheel touches the deck, add riser pads.
- Break-in: Hard wheels feel slippery for the first session, then settle. Soft wheels flat-spot if you slide them, so avoid long slides on cruiser wheels.
Frequently Asked Questions
What size skateboard wheels should a beginner get?
54mm at 99a is the safest all-purpose starting point. It handles street, park, and general riding well, and it is easy to find. Adjust from there once you know what you skate most.
Are harder or softer wheels better?
Neither is universally better. Harder wheels are faster and slide better on smooth ground, which suits parks and tricks. Softer wheels grip and absorb rough pavement, which suits cruising. Choose based on your surfaces and goals.
What does the “a” in 99a mean?
It refers to the Shore A durometer scale used to measure the hardness of the urethane. Higher numbers are harder. A separate “b” scale is used for very hard wheels; add roughly five points to a “b” rating to compare it on the “a” scale.
Can I put big soft wheels on my normal skateboard?
You can, but wheels above about 56mm on a standard deck often cause wheel bite. Add riser pads, or accept that it becomes a cruiser rather than a trick board.
How often do skateboard wheels need replacing?
It depends entirely on how much you slide and skate rough ground. Heavy street skaters may replace wheels every few months; casual riders can go a year or more. Replace them when they are visibly small, coned, or flat-spotted enough to affect your ride.
