Its on biketrials.com so i thought i would add it. Its abit outdated though but, meh!! Choosing between stock and mod Both modified and stock trials bikes have pros and cons: Modified (20" wheels) Pros: Superb standover clearance Easily manueverable in most every circumstance, especially anything rear wheel Less expensive Less parts to break Nearly impossible to bend the rim of a well-built 19" rear mod wheel running enough tire pressure Learn to sidehop up to both sides without worrying about a rear derailleur Cons: Some people may think it's a BMX bike A pain to ride more than a mile or two on May be harder to find parts for it Harder to roll down things Easier to go over the handlebars (but less scary when you do) Doing wedge or wheelbase moves is less comfortable Stock (26" wheels) Pros: More stable Bigger wheels = roll everything easier Easier to do wedge or wheelbase moves Easier to pedal-kick on odd surfaces because of the larger diameter wheel You can ride to your riding spot easily (if you have a seat and working gears) Looks more like a mountain bike People won't ask you to "grind" stuff or think you do BMX vert or street Cons: Bigger bike = less standover clearance = pain if you fall on the bike Easy to hit knees on top-tube of most bikes Less room to work with for bending down before sidehopping, bunnyhopping, etc. or when absorbing landings More expensive because of greater frequency of breakage and more parts to break Rear derailleurs - easy to smash into things (though most bikes have replaceable derailleur hangers that will bend before the derailleur is broken) Wheels - 26" size = easier to get out of true or taco (20" wheels are extremely hard to ruin when built and used properly) Chain can slip down or up a gear while you ride if your chain is too loose, or you smack your derailleur in section and break it Heavier Gav