Skateboard wheels come basically in 3 types of compounds. HARD which is used predominantly in street skating, MEDIUM and SOFT (Street cruising, Downhill and longboard). Sizes range in Street skating from 48-52MM and for ramps and pools 53-67MM. The Tallest Skateboard wheels are an 80MM, besides the Rubber Offroad wheels (Approx 110MM) which are not covered in this review.

DUROMETER _ (Duro - Meter) A Durometer measures the indentation hardness or shore hardness (or softness) of a Material like Urethane. When measured with this device it determines the Durometer of the Wheels. Durometer refers to the measured number. Soft 75A Hard 105A. The Higher the Number the harder the Compound.

HARD or Standard compounds for 2006 are approximately 99 to 101 Durometer in an A Compound usually made with Dupont Terathane. There are some Companies who use a D Compond but not many. Hard Compounds are the best for Street tricks, they will react better for takeoff and landing of tricks as well as slide and grind against all surfaces better. The size used by experienced skaters in the Street are from 49 to 50MM. Use of a 51 to 52MM wheel will last slightly longer if you do alot of Sliding. The smaller the Wheel, the ligher it is, as less urethane is used. This also applies to.........

DUAL DUROMETER WHEELS - Dual Durometer wheels have a Harder Inner CORE (ie:105 Durometer), than the actual riding surface(ie: 99 Durometer). This creates less flex on the Bearings when doing Demanding tricks and a more controlled Ride while the large inner core creates a wheel that is about 20% lighter weight than standard Wheels, which brings us to the lightest of wheels.....

AIR CORE WHEELS - Air Core Wheels are the Same as Dual Durometer except the inner Core is HOLLOW, eliminating urethane from the center of the Wheel. This is as extreme as it gets when it comes to Wheels and they are about 30% lighter than Standard Urethane Wheels or 10% lighter than standard Dual Durometer Wheels. If you want your Board to be light weight this is one place to start.

TIP: If you want a SMOOTHER RIDE with a hard compound, use a 1/8 inch rubber shock pad to smooth out the Vibration (you will have to change your bolts to1 inch).

MEDIUM Compounds are about a 90 Durometer and are almost impossible to find in skateboard wheels. Riders who prefer a firm ride, but not a Hard or Soft ride will appreciate these more. The 88 to 92A Durometer is used more as an Indoor and outdoor application for Rollerskates.

SOFT Compounds are used mostly for Cruising. This is used alot by skaters looking to just have a good time riding on the street, where there are cracks, rocks and bumps or street surfing. Sizes used are 56 to 76MM Average but do go as high as 80MM. (the taller the Wheel, the easier it is to go over UNEVEN Surfaces). The soft compounds are also used by Skateboard Videographers (also known as FILMERS in smaller 56MM sizes so they dont have to add tall risers) and the sound of the wheels is not heard while filming. One of the things when riding these somewhat Silent wheels is that you have to warn people you are coming, you will scare the crap out of people you are approaching from behind, as they might think you are  purse snatcher or ? So, a courtesy holler out to them like:  BEHIND YOU! -  is a good heads up. When Riding Boards with Soft wheels, you have to be careful that they DON'T RUB AGAINST THE DECK. If the Wheel rubs against the Deck with any pressure, it will act like an instant Brake and launch you flying into the air. On the Average a 1/2 inch riser is probably the best with a Standard 65MM Soft Compound. If you run a smaller 56MM you can try a 1/4 inch riser.

HEIGHTS OF WHEELS and TRUCKS- 52MM WHEELS and smaller can be used with a LOW PROFILE TRUCK without a riser Pad. MID and HIGH PROFILE TRUCKS can use 53 to 54MM Wheels without a Riser. All INDEPENDENT trucks are Mid profile.

Any use of a Wheel over 60MM should use a 1/2 inch riser. You may be able to get away with a 1/4 inch riser or TWO 1/8 inch risers if you keep your trucks tight and are running a Hard Compound Wheel.

Almost all wheels Have High Rebound (except Cheap Import Wheels) and that is one of the most important factors in buying quality wheels today. Having High rebound is like having air in the wheels and makes for a smooth ride and does not allow sand and dirt to penetrate the surface of the wheel. Wheels without high rebound will allow dirt and sand to be imbedded into the riding surface of the wheels. One way to test a wheel for high rebound is to drop the wheel from waist high (without the Bearings) and see if the wheel bounces back or bounces many times. The more Bounce it has the more rebound and softer the wheel is. Softer Wheels are easier to test than harder wheels. Years ago Skaters used to bite the wheels to test the Hardness.  If a Wheel drops like a rock (or sounds like one) it does not have any rebound whatsoever!  (Be careful when buying low priced blank wheels) If you are buying Skateboard wheels with an Industry Brand name, they will ALL have high rebound.

HISTORY - Kryptonic's was the 1st Wheel Company to make wheels with high rebound and are still making wheels today. The 1st Wheels were a 78A Soft Compond. In the late 70's and Early 80's Krptonics made 3 Compounds. 78A RED - 88A BLUE - 92A GREEN.