The Infernolab::::Robot Wheel Comparison Guide

STORY: After acquiring drive motors and gearboxes for Dr. Inferno Jr., I needed to find the best wheels to put the power to the ground. In past robots, I generally used crazy custom wheels tailored to the application. I didn't have much experience picking out appropriate wheels from a catalog, so I ordered a whole bunch from McMaster-Carr and Tower Hobbies and did a qualitative, subjective comparison (that is, I didn't actually mount & test most of these wheels on bots--many of my comments are based on impressions I got from handling & studying them).

THINGS TO LOOK FOR IN A WHEEL FOR A COMBAT ROBOT

Light weight: makes it easier for your drive motor to quickly speed up, slow down, and reverse direction; heavy wheels also use up valuable weight that could be better used in other components
Sturdiness: needs to take a beating and not break up
Tread: the stickier the better for pushing and high acceleration/deceleration
Diameter: for a given drivetrain setup, smaller wheels give more pushing force and lower top speed, larger wheels give less pushing force but higher top speed; using smaller wheels should also tend to draw less current, letting your robot run longer on a battery charge and taxing your speed controller less
Tread Shape: flat gives more contact area (better), rounded gives less contact area
Core/Hub: want it to be sturdy yet easy to machine, with enough area to attach to driveshaft or hub
Stiffness: cushy wheels will have a larger contact patch, give your robot a smoother ride, absorb shocks, and accommodate mounting flaws (tweaked chassis, bent axles, etc.) but may wear faster than hard wheels
Cost: try not to let cost influence your decision too much; then again, you always want to be able to afford to have spares on hand; all prices quoted below are from March 2000
Application: wheels designed to support push-carts or to catch landing model airplanes are not designed to be driven by motors--reworking of the hubs is necessary. Any text below in "quotes" is taken from the catalog descrption, explaining its features or application.

If you want to learn about other drivetrain issues or want to see a rough rule of thumb for preferred wheel/tire size, visit Coolrobots' builder's corner.

Wheels	Description	Pros	Cons	Verdict
McMaster-Carr 2322T31	ALUMINUM HUB Rubber tread on aluminum core (solid or spoked), smooth tread (thin or standard thickness), 150+lb capacity, size: 5"-14" dia x 1.5"-5" wid Example: 3" dia x 1.25" wid, 0.5lb, $22.24	light, quite grippy tread, tough hub, small hub bore on larger sizes, easy to machine aluminum	smaller sizes have large hub bore, pricey, raised central ridge on tread, rounded tread	Recommended Easy-to-remove bearings, easy to machine, light & grippy. Suitable for all sizes of bots.
left: McMaster-Carr 2829T11 right: McMaster-Carr 2829T54	COLSON THERMO-CUSHION RUBBER PERFORMA Polyurethane tread interlocked on smooth or ribbed polyolefin core, gray tread or black tread available (gray appears softer), 75+lb capacity, size: 2"-12" dia x 0.125"-3" wid Examples: left 3" dia x 1.5" wid, 0.3lb, $9.89; right 3.5" dia x 1.25" wid, 0.3lb, $7.13	light weight, quite grippy tread, small hub bore on larger sizes, tread compresses, reasonable price, easy to machine, flat tread	smaller sizes have large hub bore, plastic may not be durable enough	Recommended Easy-to-remove bushings, easy to machine, light & grippy. May not be suitable for huge bots. "Tread will not break up when rolling over debris." Dr. Inferno Jr. was upgraded to Colson wheels after the CB ones shredded.
left: McMaster-Carr 22865T11 right: McMaster-Carr 4996T11	ALUMINUM HUB left: Rubber tread on aluminum core (solid or spoked), smooth tread (thin or standard thickness), 150+lb capacity, size: 5"-14" dia x 1.5"-5" wid right: Neoprene molded on solid aluminum core, smooth tread, 200+lb capacity, size: 4"-10" dia x 1.5"-2.5" wid Examples: left 5" dia x 1.5" wid, 1.5lb, $22.24; right 3" dia x 0.9375" wid, 1.3lb, $18.69	average weight, small hub bore, fairly grippy tread, very durable	average weight, average tread grip, raised central ridge on tread should be removed first, not cheap	Pretty decent for a heavy duty bot. Overkill for a small one. Tread needs a little work to remove ridge.
orange: McMaster-Carr 2351T97 red: McMaster-Carr 2351T98 black: McMaster-Carr 2319T11	IRON orange & red: Polyurethane molded on cast iron core, smooth thin tread, 290+lb capacity, size: 3"-12" dia x 1.25"-4" wid black: Rubber molded on solid or spoked iron core, smooth tread (hard high capacity or less hard lower capacity), 170+lb capacity, size: 3"-16" dia x 1.375"-5" wid Examples: orange 3" dia x 1.25" wid, 1.5lb, $12.45; red 3.5" dia x 1.25" wid, 1.3lb, $13.21; black 4" dia x 1.5" wid, 2.6lb, $7.52	cool colors, bulletproof, small hub bore	not-so-grippy tread, heavy!	Too heavy & not grippy enough. Not well-suited for robot drivetrain.
blue: McMaster-Carr 2472T21 gray: McMaster-Carr 2497T121	PLASTIC blue: Solid polyurethane, smooth tread, 300lb capacity, size: 3"-8" dia x 1.25"-2.5" wid. gray: Polyurethane tread mechanically locked on polyolefin core, smooth tread, 125lb capacity, size: 3"-12" dia x 0.9375"-3" wid Examples: blue 3" dia x 1.25" wid, 0.3lb, $12.89; gray 3" dia x 0.9375" wid, 0.2lb, $3.56	light, small core bore, 1-piece models are simple	skinny, not grippy, all plastic (durability?)	Ok for a very light bot, perhaps not for larger ones. Easy to work with. 2497 series is low cost!
black: McMaster-Carr 2670T14 maroon: McMaster-Carr 2670T83	WIIIIIDE Polyurethane tread on steel core pallet and lift truck wheels, smooth tread, size: 3"-8.5" dia x 2"-6" wid Examples: black 3.375" dia x 3.9375" wid, 3.0lb, $19.56; maroon 3.25" dia x 5.9375" wid, 3.5lb, $24.24	extra wide, very durable	large core bore, not very grippy, heavy, not cheap	Crazy! Maybe good for a giant bot, especially if a stickier tread could be applied. Silly for a smaller bot. "Abrasion resistant."

top: Tower Hobbies CBAQ3020 bottom: Tower Hobbies CBAQ3010	CB/TATONE FOAM-FILLED R/C AIRPLANE WHEEL C.B./Tatone foam-filled wheels, "support airplanes weighing up to 100lb", treaded wheel size: 3.5"-4.5" dia, smooth wheel size: 4"-5" dia Examples: top smooth, 4" dia x 1.5" wid, ~0.2lb, $21.39/pair; bottom Bow-Tie, shallow tread, 3.5" dia x 1.5" wid, ~0.1lb, $21.39/pair	light, grippy, cushy, fairly hearty hub disassembles easily, durable foam-filled tire can take some abuse	price, rounded profile (on both smooth and treaded models), a little skinny, tires wear noticeably during heavy use	Recommended Good all-around model. Reinforce the hubs or make beefier ones. Not cheap but worth it. Good for small bots, not big ones. I used 3.5" ones on Dr. Inferno Jr. with custom aluminum hubs. The wheels ended up wearing somewhat on Overpowered Box & totally shredding themselves on Dr. I Jr.
top left: Tower Hobbies DAVQ5540 top right: Tower Hobbies DAVQ5730 bottom left: Tower Hobbies DAVQ5740 bottom right : Tower Hobbies DAVQ5035	DAVE BROWN LITE FLITE FOAM-FILLED R/C AIRPLANE WHEEL Dave Brown Lite Flite foam-filled wheels, "for large scale airplanes", smooth & flat or treaded & rounded, size: 4"-6" dia Examples: top left 4" dia x 1.125" wid, ~0.1lb, $8.59/pair; top right 3" dia x 0.75" wid, ~0.1lb, $4.99/pair, bottom left 4" dia x 1.25" wid, ~0.1lb, $8.59/pair; bottom right 3.5" dia x 0.875" wid, ~0.1lb, $5.49/pair	light, seem grippy, smaller models squishy, smooth wheels have flat tread, cheap price	larger models stiffer, treaded wheels have rounded tread, plastic hub durability questionable	Recommended A good all-around model. Reinforce the hubs or make beefier ones. Very high profile tires. Very inexpensive. Good for smallish bots, not for big ones.
Left: Tower Hobbies DUBQ0775 top: Tower Hobbies DUBQ0895 bottom: Tower Hobbies DUBQ0843	DU-BRO AIR/FOAM-FILLED R/C AIRPLANE WHEEL left: Low Bounce, captive air rubber tire on nylon hub, smooth tread, size: 1.75"-3.5" dia top: Low Bounce captive air rubber tire on nylon hub, shallow lined tread, size: 1.75"-3.5" dia bottom: Lightweight foam-filled rubber tire on nylon hub, shallow lined tread, size: 1.75"-6" dia Examples: left Low Bounce smooth, 3" dia x 1" wid, ~0.1lb, $5.49/pair; top Low Bounce treaded, 3.5" dia x 1.25" wid, ~0.1lb, $5.99/pair; bottom Lightweight treaded, 3.25" dia x 1.25" wid, ~0.2lb, $8.59/pair	seem grippy, captured air model cushy, very inexpensive, teeny hub bore, light weight, foam-filled model more durable	captive air versions may puncture, spoked plastic hub offers little support, foam-filled model very stiff, overall durability a concern	Some potential if they can be mounted well and do not get damaged. Small bots only. Captive air models have good tires but potential puncture problems, foam-filled is more durable but stiffer. Hubs are minimal & skimpy.
Tower Hobbies DUBQ0790	DU-BRO INFLATABLE R/C AIRPLANE WHEEL Du-Bro Big Wheels Smooth Tire with positive seal valve, size: 4"-6" dia Example: 4" dia x 1.5" wid, 0.3lb w/ hub, $11.59/pair	mega-grippy, very cushy, low cost, teeny hub bore, light weight	air-filled tire can pop or leak, rounded tread, air valve near tread could get damaged, weak plastic hub	Much potential if they can be mounted well and do not get damaged. Small bots only.
Left: Tower Hobbies PROC9002 right: Tower Hobbies PROC9004	PRO-LINE 1/8 SCALE R/C CAR TIRE Pro-Line Road Rage & Bow-Tie, tire only--no hub, diameter, "fits any 3.2"-3.4" front or rear 1/8 wheel" Examples: left Road Rage off-road knobby, 4" dia x 2" wid, ~0.1lb, $18.39/pair; right Bow-Tie, street tread, 4" dia x 2" wid, ~0.1lb, $18.39/pair	light, wide, flat tread, sticky, Bow-Tie well-suited for flat surfaces	need to purchase or make hubs, questionable durability, Road Rage tread suited for off-road use	Not good for a beginner (need to buy or make wheel/hub), nice piece of tread if mounted properly.

Missing Link with screwed-down vacuum cleaner belts	VACUUM CLEANER BELTS Available at any vacuum shop, hardware store, or department store. Examples: Precision "traction" belts, $1 each	cheap, super grippy, customizable (number and arrangement of belts)	not durable, assembly required, need to be attached to a correct-sized wheel hub	Good solution for a smaller robot if custom wheels are desired, not good for a big bot.