Gravel Conditions / Categories
*Thanks to Neil Shirley for giving us permission to use his Industry Standard Guide to Gravel (ISGG)
Types of Gravel*
Category 1 Gravel
Smooth, well maintained dirt roads that have either very small gravel chunks, or none at all, and are very much road bike-friendly. These roads are in better condition than many paved roads in the U.S. and are hard packed, offering little more difficulty than riding on tarmac. There are a number of roads like this in Colorado that have a magnesium chloride treatment to keep the dust down and harden the top layer of dirt. Roads like these are often found in a number of Gran Fondos to add a little more adventure to the event.
Ideal bike: Road bike
Tire size: 25-28mm
OGG routes with this type of gravel: Scioto Trail State Park
Event examples: Haute Route Rockies, Battenkill Roubaix
Scioto Trail State Park
Category 2 Gravel
Expect potholes, washboard and probably loose, blown out corners. There is likely to be gravel outside of the main tire tracks that could cause an extra challenge if one was to come off their line. A road bike is just fine, but more skill is needed when cornering at speed. Going up in tire size compared to an everyday road setup is recommended in order to benefit from the reduced risk of pinch flatting and pneumatic suspension a higher volume tire allows.
Ideal bike: Endurance road bike
Tire size: 28-32mm
OGG routes with this type of gravel: Bladensburg 39
Event examples: Gravel Worlds, Dirty Devil, Boulder Roubaix, Belgian Waffle Ride
Category 3 Gravel
Infrequently maintained roads that require a high level of skill when tackling on a road bike due to exposed rocks, tire eating rain ruts, sand bogs and any number of other unexpected challenges that could arise around the next corner. Unless a Category 3 Gravel section is added merely as a short connector, a gravel bike with 33-38mm tires that offer side knobs is the recommended equipment to achieve both speed and safety.
Ideal bike: Gravel bike
Tire size: 33-38mm
OGG routes with this type of gravel: Shoots & Ladders, Candyland
Event examples: Rebecca’s Private Idaho, The Mid South, Crusher In The Tushar, Rock Cobbler, Gravel MOB, SPNDX Stampede, Chino Grinder
Category 4 Gravel
Non-maintained Forestry roads common in California would be considered Category 4 due to deep ruts, rock gardens, and potential landslides left for the next gravel rider to stumble upon. Going with high volume tires will help provide pneumatic suspension, reduce the risk of a pinch flat, and provide greater traction is in the corners and on steep, loose climbs.
Ideal bike: Gravel bike
Tire size: 38-42+mm, or Road Plus (650b wheels with 42+mm tires)
OGG routes with this type of gravel: Tar Hollow Adventure 40, Tar Hollow Adventure 29, Danville-Walhonding 41
Event examples: Unbound Gravel, Grinduro, Lost and Found
Route: Danville-Walhonding 41 - Bats Nest Road
Fine print
By participating in any offline arranged ride or activity, you, your heirs, executors, administrators and representatives do hereby agree and will absolve and hold harmless Ohio Gravel Grinder organizers, it's corporate sponsors, cooperating organizations, and any other parties connected with this web site in any way together with their respective successors from and against any blame and liability for any and all losses, damages, rights, claims, and actions of any kind including, without limitation, personal injuries, death, and property damage, or any other damage of any kind whatsoever either directly or indirectly related to or arising from your participation in any such offline Ohio Gravel Grinder organizers arranged ride or activity.
User assumes all risk and liability for any action in relations to usage of information and routes on ohiogravelgrinders.com, including if actions result in injury, death, loss or damage of personal property or other complications. Ohio Gravel Grinders, its partners, associates, and contributors accept no liability. Route information and advice is provided as a planning resource only, and is not guaranteed to be accurate or complete, and in no way should replace your own due diligence, research, and safety precautions. All users are advised to check current conditions before embarking on any route, including weather, surface conditions and closures. Riders should obey all laws including public and private land usage restrictions and guidelines and carry adequate safety and navigational equipment.