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Dual Purpose Tires & Rim Fitment

by K.D. Laughlen                                           rev. 23 Mar 2010

This guide is intended to help you get an idea of the variety of tread patterns available for adventure and dual purpose/dual sport bikes and to choose the tire sizes best suited to the rims that are fitted to your bike. There are a number of D.O.T. full knobbies suitable for dual sporting as well but their sizes and fitment all fall within a very narrow range so the focus of this article is the tires of more moderate pattern and wider application. Following the text you will find a chart of tire brands, models and specifications. Below that you will find some information about speed ratings, followed by images of many of the tires listed in the chart.

The information in the chart is drawn from the tire manufacturer’s catalogs when available. For each tire size, the manufacturer's have a preferred rim width, highlighted here in bold, within a range of acceptable widths. Typically, the tire dimensions given, such as diameter and width, are taken with the tire mounted on the rim width listed in bold type. The nominal size ( e.g. 130/80-17 )  is a perfectly fine, if rough, guide for size to see if you are in the ballpark when you are looking for a tire. The construction and final shape of a tire depend on the design choices made by the tire engineers so it is common for a given nominal tire size from one manufacturer to have different mounted diameter and width dimensions than the same tire size from another manufacturer. It is probably fair to assume that a tire of any brand and model of a particular nominal size will fit your bike without interference problems if the bike originally came from the factory with the same nominal tire size. This is more of a sure thing if the tire types are similar, say road tire replaced by road tire, and less off a sure thing if you change from street tire to a full knobby. How replacement with the same size and type, but a different brand & model, might affect the handling characteristics is a more complex question. Depending on the rider’s skill level and sensitivity, these changes can be dramatic to minor, perhaps unnoticeable. If you need more precise information to see how a given tire might affect chassis geometry and handling or clearance issues, measure your old tire or use the specifications for it, and then compare with the mounted dimensions of the tires you are considering. There are other characteristics such as cross sectional profile, rubber compound, tread pattern, etc. which can greatly influence a tire’s performance, but you can’t generally find that information on a chart. That is where we can help you select a tire.

The practical differences in mounting a given tire on different rims within the acceptable range will be a change in the tire’s cross sectional profile and felt mostly, if at all, in the transition from riding upright to leaning over toward the tire's edge. If you step beyond the recommended rim range, you might reasonably expect more profound changes in handling, load bearing and wear characteristics. I believe this is much more of an issue on pavement than on dirt. If you typically push the sporting envelope on pavement and/or run a heavily loaded bike, the less you should deviate from the rim recommendations. On dirt bikes ( I would include dirt oriented adventure bikes here as well ) it is common to choose a tire/rim combination depending on the specifics of an application. If serious dirt riding is in the cards, fitting a tire to a rim on the narrow side of, or even beyond the narrow side of, the “normal” range, is often done so that the rim is well protected from impact damage, and the tube is protected from pinch flats. As example, you frequently find a 140 section rear tire fitted to a 2.50” rim. I suspect this doesn't noticeably affect cornering because the transition from upright to leaned over in the dirt is much more influenced by tread pattern and soil type than tire profile. If you expect to spend more of your riding heavily loaded, or on pavement and improved dirt roads, you might choose a combination that mounts the tire on a rim at the wider side of the acceptable range. This spreads the tire a bit at the rim, giving the tire sidewall a wider base of support.

We invite you to e-mail us with any questions you have and we are always interested in receiving feedback about tires you have tried. Also, please let us know if you find errors in the information we have provided.

Ken

                    Tire Brands, Models & Specifications

 * Mefo SE ( Super Explorer) appear to be identical to Heidenau K60, perhaps even from the same mold

Speed Rating

Although I do not have an authoritative reference for this, my understanding here is that this means the tire must withstand a 10 minute run at the speed listed for the rating designation without sustaining damage. Occasionally flirting with the speed rating limit should not pose a danger of tire failure. A higher rated tire is not necessarily a better choice. You can benefit from choosing a tire with a speed rating closer to your actual real-world usage. Generally, a tire with a lower speed rating will warm up more quickly with less provocation so it should reach operating temperature more readily and in colder conditions than a tire with a higher rating. So, tires chosen to match your real world usage should stick to the road sooner and work better in a wider range of weather conditions ( think rain cooled pavement ). Choosing a suitable tread pattern is a far more important criteria, but just keep the speed rating issue in mind when you are looking at options.

                                               Tire Tread Patterns

Michelin T63