Copyright 2000 ,

Pumped Up!
A WheelchairJunkie's Guide to Sportschair Tires
By Mark E. Smith

It used to be that when you needed tires for your sportschair, you got “everyday-grays,” 1-3/8”-wide tires with a “street tread” pattern, produced by Cheng Shin Tire Company.  The everyday-gray tires -- still common today -- were non-marring, and worked well under daily conditions.  However, as wheelchair technology flourished in the 1980’s, and consumers demanded more from their sportschairs, specialty tires emerged, catering to everyone from the tennis player to the mountaineer.  Today, if your tires aren’t activity specific, you might as well be playing basketball in combat boots, or hiking in eight-inch heals -- to warp a phrase, tires aren’t just tires anymore.

Clincher vs. Sew-up Tires
“Clincher” (also called wired-on), is the most common type of tire used on sportschairs.  The term clincher refers to the way the tire is attached to the wheel rim.  A clincher, which always has a sperate innertube, features a metal wire as a bead (the inside edge of the tire that fits on the rim), which grips the rim when inflated, clinching it, just like a car tire.  Clinchers are inexpensive, durable, and easy to change, which is why they’re so popular.

“Sew-up” tires (also called tubular), have the innertube sewn in them, creating a one piece tire that’s glued to the wheel rim.  Racing chairs have long used sew-ups because they’re lighter in weight and structurally stronger, allowing higher air pressure and less rolling resistance than clinchers.  However, sew-ups have a much thinner tread and innertube than clinchers (which explains the weight difference), so they are susceptible to punctures.  What’s more, most users have to discard a sew-up when they get a flat because it’s so difficult to repair the tire -- that is, you must remove the glued-on tire from the rim, unthread the tire, patch the tube, sew the tire shut, then glue the tire back on the rim.  With prices ranging between $25 to $110 per tire, sew-ups are expensive, so if you get a flat, be prepared to spend a lot of money to replace it, or exercise a lot of time repairing it.

Clinchers and sew-ups require different wheel rim styles -- clinchers use a box-shaped rim, and sew-ups, a dish-shaped rim -- so you can’t place the different tire forms on the same rim (I have seen users muscle sew-up tires onto clincher rims, but it’s not advisable, and clincher tires on sew-up rims absolutely don’t work).

Shrader Valve vs. Presta Valve
Shrader and presta are the types of valve-stems used on innertubes.  In the U.S., we almost exclusively use shrader valves on everything from cars to bicycles, so it’s the most common style.  However, presta valves are common in Europe, and found on sew-up tires and ultra-lightweight clincher tubes that need an aerodynamic, lightweight valve-stem.  From a performance point on sportschairs, neither valve style has an advantage over the other; however, from a practical view, you’re better off using the most common valve in your country -- that is, if you live in the U.S., your best bet is to use a Shrader valve, as that’s the style for which most air pumps are designed.

Pneumatic vs. Semi-pneumatic and Solid Tires
Put simply, a pneumatic tire is filled with air, semi-pneumatic is a clincher tire with a “solid” tube instead of air, and a solid tire is entirely formed from one piece of rubber.  Being that a user’s worst nightmare is a flat tire, semi-pneumatic or solid tires seem like the best tire form.  However, while airless tires do prevent flats, as well as eliminate the regular maintenance of tire inflation, they dramatically hinder a chair’s performance.  One of the primary consumers of energy on a sportschair is the rotational weight of the rear wheels, meaning that a heavier wheel is harder to propel than a lighter one.  Wheelchair racer mythology says that one extra ounce at the outside edge of your wheel equals one extra pound at the frame.  A semi-pneumatic or solid tire can weigh up to four times as much as a clincher tire and tube, so by using airless tires, you may be killing your chair’s performance with the increased rotational weight.  This isn’t to say that airless tires shouldn’t be considered, as they are a great solution for many users.  However, if you want the most efficient chair, pneumatic tires are the best choice.

Psi Ratings
Every pneumatic tire carries a “psi” rating, which designates the tire’s firmness.  As a rule, the lower the psi rating, the softer the ride.  On the other hand, the higher the psi rating, the easier a tire rolls on a smooth surface.  For everyday tires, look for a 65psi rating, and a 90-100psi rating on court tires.

Tire Choices

Everyday Tires

Everyday-grays, as they’re listed, are the industry staple, and are factory equipment on most sportschairs.  With a width of 1 3/8”, psi rating of 65, and a lightly-grooved tread pattern, everyday-grays are small enough to be efficient, yet large enough for adequate traction and flotation over obstacles.  What’s more, they’re thick enough to prevent many punctures, and work well with brakes.  At $14.00 per pair, everyday-grays are the most economical tire, and a great choice if you use your chair under a wide range of conditions.  (Note, many dealers charge $24-$36 per pair -- if you’re paying more than $14 for the set, you’re getting taken.)

Primo's Extreme is a  1 3/8”-wide everyday tire lined with kevlar -- the material used in bulletproof vests -- which is supposed to protect against punctures.  However, the tire doesn’t work as advertised, and allows thorns and nails to pass through the tread, puncturing on par with regular everyday tires.  At $29 per pair, they are a huge waste of money.

KIK Mako tires are solid rubber, with a slightly-textured tread and low profile.  As solid tires go, Makos are top-of-the-line, offering a slightly softened ride and an adhesive grip on the ground.  The Makos come in non-marring black, so you have an option besides gray.  Makos are expensive -- $42 per pair -- and require a $25 tool for installation.  But, if you really want solid tires, KIK is the name to choose.

Sport ‘n Court Tires

Primo's V-Trak Blackside is the tire of choice for the court crowed.  At 1” wide, ultra-lightweight, and a 100psi rating, V-Traks are the most efficient tires for smooth, hard surfaces.  While many users these days have V-Traks on everyday chairs, it’s probably not the most practical tire choice (V-Traks are easily punctured, don’t provide adequate traction on less than smooth surfaces, offer a brutally-hard ride, don’t work well with brakes, and destroy pushrims due to low ground clearance).  At $24 per pair, V-Traks are worth the price -- but keep them on the court!

Continental Sew-ups are “old school,” as the hip kids say.   Back in the 1980’s, Continentals were the only tire you’d find on the court.  With a rating of 100psi, 1” or 1-1/8” width, and a gummy tread, Continentals are made for sports.  They are, however, heavy and very expensive -- $39 each! -- and all but impossible to repair.  . . . Now you know why Continentals are old school, and the hipsters sport V-Traks!

KIK  Pyramid tires, like the Makos, are solid rubber.  The Pyramids, however, feature a tapered profile -- like a pyramid! -- that creates less rolling resistance for court use.  Even cooler is that the Pyramids come in red, blue, black, and gray.  Costing $32 per pair -- plus the $25 installation tool -- Pyramids aren’t too expensive, but they are slightly heavier than V-Traks, which may slow you down.  Still, being as V-Traks and Continentals require frequent inflation due to their thin tubes, it may be worth going to the Pyramids to avoid hassling with inflation every game.  . . . And don’t overlook the color options of red or blue -- there’s nothing cooler than sporting gang colors on your chair!    

Knobby Tires

Primo's Knobby Blackside tire comes in 24” x 1-3/8”, with a 65psi rating, and is gray so it won’t mar floors and walls like black knobby bicycle tires.  The unique feature of the Knobby Blackside is that it allows the installation of a knobby tread on a standard wheel rim (several companies make gray knobby tires, but they’re commonly 1.95” wide, requiring a special rim and wheel clearance adjustments on the chair’s frame for installation).  If you want a more aggressive tread pattern, without sacrificing everyday practicality, the Primo Knobby Blackside -- $28 -- is a winner.

Everyday-gray Knobby tires are 24” x 1-3/8” x 1-1/2”, which makes them “balloon,” providing a wider tread than the Blackside Knobby to float over soft surfaces.  However, the 1-1/2 tread width requires more wheel clearance from the frame, so you may need to readjust your chair.  At $35 per pair, 65psi everyday-gray knobbies are a tad costly, but may be a solution if you need a wider tire than the Primo Knobby Blackside, but don’t want to invest in a set of 1.95” wheels.

Indeed, there are many tire choices, and by picking the style that’s right for your use, you’ll roll through life’s adventures easier than ever before.  One last thought:  Do you suppose we’ll ever see wheelchair athletes endorsing signature tires?  I can see it now, the Air Killey tire!

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