The section width of a tyre is a design target that includes the cross-sectional width of the tyre minus all lettering and protrusions. The diameter of a tyre measured after the tyre is mounted on the design rim width and inflated to the design inflation pressure for 24 hr. Design load, inflation and rim dimensions are listed in ETRTO and Tyre and Rim year books as well as the BKT Data book. These measurements are done on an unloaded tire. the inflation pressure is readjusted to the design inflation pressure as needed, then the tyre is measured.
The tyre is inflated to the designed inflation pressure and held that way for 24 hr. All new tyre designed dimensions are measured on the design rim width. Dimensions such as OD (overall diameter), SW (section Width), OW (overall width) for new tyres and are important to consider when matching a tyre to a specific piece of equipment. The above tire sizes correspond to the new tyre designed dimensions for each tire type and size. The chart below lists the different types of size designations you may see stamped on an OTR tyre sidewall along with what they mean. Each size marking contains important information about the dimensions and capacity of the tyre. Off-The-Road tyres are labelled for size in one or more ways.
There is much work being done through ISO and other organizations to homogenize these standards world wide. Also, these various industry standards may not always match up especially for load and inflation. Caution: Adherance to the standards is not mandatory so there may be tyres that do not follow any standard. Most tyre manufacturers follow one or more of these industry standards in designing their tyres. India – Indian Tyre Technical Advisory Committee (ITTAC) (TRA)Įurope – The European Tyre and Rim Technical Organisation (ETRTO) BKT’s Off-The-Road tyres are designed and produced to meet commonly accepted international standards.īKT is a participating member of the following industry standards organizations: The goal of these guidelines is to ensure tyre and rim compatibility and interchangeability for fitment, load, dimensions and application.īKT has developed a wide range of OTR tyres, so that the proper tyre can be matched to any piece of equipment, service or operating conditions. For OTR tyres these nonbinding guidelines include critical information such as size nomenclature, load, inflation pressure, and tyre type or application code. These organizations exist to establish and publish application and service guidelines for tyres and rims. Or just plain r/bicycling, which also has links to more subs.There are many tyre standards organizations worldwide. R/JustRidingAlong "Pictures and stories of some of the most egregious user-error and bad luck damage on bicycles." R/BikeMechanics Discussions among bike mechanics, professionals and advanced amateurs. Outlets for posts that don't belong here: R/Vintage_bicycles/ for pre-1986 bicycles. R/Bikebuilding for discussing and showing off bikes built up from a frame. R/wheelbuild and r/Framebuilding for construction of those components. R/bicycleengineering: bicycle technology from an engineering perspective. A comment with an overview and links to more information. Park Tools' Repair Help including illustrated text and video guides to service procedures.Ĭold Setting Steel Frames: adjusting the dropout spacing on a old frame to fit a more modern drivetrain. A comprehensive resource with answers to common and obscure questions, data tables, etc., including a glossary which also serves as an index. Stay on topic / No jokes, especially not false answers as jokes. Tag helpful commenters if you want them to receive a notification. Please use the weekly thread for post follow ups and acknowledgments. They should have the equipment and expertise to inspect it properly. If it's carbon, a specialist repair shop may be required. Take it to your Local Bike Shop and ask them. We probably can't tell from a picture just what condition your bike is in.
"Is this cracked / safe to ride?" - If you have to ask, don't ride it. If you just want to post a picture, this isn't the place for it. You can also consult our FAQ or the list of people willing to help locally.
It really, really helps if you can provide pictures and/or video. Post your problems, and we will try to get your bike rolling again. A community of cyclists - some with questions, some answers Post questions to get help.