From lightweight Enduros and Small ADV Bikes to Scramblers and Long-Haul Touring machines, dual sport tires are used on a wide range of motorcycles these days. Along with this diversity comes a variety of different types of riding from RTW travelers exploring the far reaches of the planet, to aggressive off-road day rides out on the trail.
One thing we all have in common though is a desire to get the most out of our dual sport rubber because let’s face it, tires aren’t cheap and changing them isn’t something anyone enjoys. The more you ride, the faster you go through them, so If we can make our tires last a little longer, that’s a good thing too. Yet performance is equally important. Ensuring our tires are properly set up and maintained is essential to the quality and safety of our rides.
With that said, there are a lot of questions out there about what you should, can, and can’t do with your dual sport tires to make them last longer and perform better. To bring some clarity on this topic, we reached out to Dunlop to get the lowdown from one of their top motorcycle tire design engineers, Ron Winkelman, who’s been working in the industry for 32 years in all facets of tire development. He also grew up riding dirt bikes on the farm and still rides street bikes today, which gives him a real-world understanding of a motorcycle’s traction needs both on and off-road. Ron shares his insights below on some of the common questions and misconceptions about dual sport tires prevalent in the adventure motorcycling community.
1.) Increasing your tire pressure several pounds above the manufacturer’s recommendation improves gas mileage and reduces tire wear.
Ron Winkelman: This may result in a very minor amount of mileage and tread wear improvement, but it’s hardly worth sacrificing ride comfort and performance. In fact, overinflating a tire can create irregular tread wear and reduce traction. It’s important to remember as you increase air pressure, the contact patch (rubber on the road) becomes smaller thus impacting grip and handling characteristics.
Manufacturer recommended air pressures are based on a combination of mileage, handling and ride comfort on a variety of pavement and dirt conditions. You should never go beyond the max operating pressure stated on the tire’s sidewall.
2.) Always use the motorcycle manufacturer’s tire pressure recommendation.
RW: For street riding, you can use either the motorcycle manufacturer’s or tire manufacturer’s recommended air pressure and decide what works best for you. The motorcycle manufacturer’s pressure recommendation can be found in the owner’s manual or on the vehicle placard. Dunlop’s recommended pressures are listed on our website, and reflect what we feel provide the best overall handling and tire wear for a particular tire and bike model.
This is different from the pressure listed on the tire’s sidewall, which refers to the tire manufacturer’s maximum pressure setting at maximum load. Also, it’s typical to lower your pressure below manufacturer recommendations in the dirt to improve ride comfort and traction.
3.) Is there a general rule of thumb for how much you can reduce your tire pressure for off-road use?
RW: How much you can air down safely will depend on the bike and how much weight you are carrying. If you are fully loaded, with all your adventure travel gear, start with the max tire pressure listed on the sidewall of the tires. Otherwise, start with the manufacturer (vehicle or tire) recommended air pressure. Then you can begin to drop pressures for off-road use in small increments to find what works best for you. Be careful not to lower it too much though or you can run into pinch flats or rim dings. The more weight you carry, the less you can air down safely.
Always remember to air back up once you reach pavement again. If you don’t have a way to air up again when you are finished riding off-road, only reduce air pressure a few psi. On bigger bikes, you never want to use less than 22psi in front and 26psi in the rear when riding on the highway.
4.) When you see irregular tread wear it’s a sign of a defective tire.
RW: Most of the time, irregular tread wear is caused by improper air pressure. I like to stress the most important tire maintenance you can perform is checking: air pressure… Air Pressure… AIR PRESSURE… If you see more wear in the center than on the edges, this is an indication of over inflation. Worn edges near the shoulder is an indication of under inflation. Front and rear tire cupping (a pattern of scooped out areas) can be caused by improper air pressure, suspension problems and hard braking. Torn lugs can also be caused by improper air pressure. Cracks either between lugs or along the sidewall could be either over inflation or tire age. Consider replacing any tire that is 10 years older than its manufacture date.
5.) Knobby-style tires wear the same on asphalt as they do on dirt.
RW: No, running knobby-style tires on asphalt will wear them down faster than on dirt. Knobby tires are designed to dig into a surface like dirt or sand. While riding on pavement the knobs can’t dig into the surface, so this causes an extreme amount of lug deformation. Lug deformation is created as the tire rotates and during braking which wears down the lug. Filling the tires to the recommended air pressure will help reduce the wear slightly, but this just stiffens the carcass, it doesn’t stiffen a knob or affect the pattern of a tire.
6.) Speed wobbles on the highway are to be expected with knobby tires.
RW: Running DOT knobbies at highway speeds shouldn’t cause speed wobbles. If you are getting speed wobbles on any type of tire, first check that you didn’t throw a wheel weight, especially, if you just finished riding off-road. Mud or debris stuck in wheel spokes may also be the culprit. Any imbalance or out-of-roundness in the front wheel may cause a wobble as well. You can also check for missing or torn tire lugs and irregular tread wear.
Always make sure items in your luggage are tightly secured and not moving around. Load your side bags so the items inside are as evenly balanced as possible. And always check tire pressure… If all else fails, inspect chassis components like the steering system, suspension, bearings, forks, springs, bushings, etc.
7.) Maxing your load capacity is something you rarely need to worry about.
RW: Maxing out the load capacity is definitely something you should be concerned about, especially for adventure riders who carry a lot of gear and potentially a passenger. Exceeding the tire’s load by underinflation and/or overloading will impact handling, overstress the tire carcass, cause premature wear and can eventually lead to tire failure.
There are two types of load capacities you need to be aware of – the GVWR (Gross Vehicle Weight Rating) and the max weight rating of each individual tire. You want to make sure you never exceed either of these load capacity limits. The GVWR can be found in your owner’s manual or on the bike’s VIN plate. Max tire loads at max pressure are stamped on the sidewall of the tires. For fully-loaded, high-speed applications, inflate tires to their max PSI listed on the sidewall to maximize load-carrying capacity.
To calculate your total load, begin by adding up the weight of the bike with fuel, the rider with gear, passenger with gear, as well as the weight of your luggage and any accessories you’ve added. If that number doesn’t exceed the GVWR, then you are within the bike’s max carrying capacity. In addition, you should check that you are within each individual tire’s load-carrying capacity limit. For a quick math check, you can assume 50% of the total load is over the front tire and 50% is over the rear tire (typical for dual sport and ADV bikes). As long as half of your ‘total load’ does not exceed the ‘max tire load’ of either tire, you are not overloaded. If you are close to the limit, you may want to consider reducing the amount of weight you are carrying.
Exceeding your max load limit is easier than you might think. Here’s an example:
Let’s say you have a 2016 Honda Africa Twin with a GVWR of 907 pounds. The bike with fuel weighs 515 pounds, you and your gear weigh 230 pounds, you’ve added 35 pounds of off-road protection, racks and auxiliary lights, and you are carrying 60 pounds of tools, camping gear and luggage. That would put you at a total load of 840 pounds, which is within the vehicle’s max limit. To check tire load, splitting the total load in half gives you roughly 420 pounds of load on each tire. A check of the tire sidewalls reveals the front has a max load limit 467 pounds @ 41psi and the rear has a limit of 739 pounds @ 41psi, so you are within the range at max pressure for each tire with the load you are carrying in this example.
However, let’s say you forgot to raise your air pressure and stayed at the ‘unloaded’ recommended pressure of 29psi in front, your max tire load is only 342 pounds at that pressure and you’d be well over the limit. Likewise, if you decided to add a passenger who weighs 140 pounds (total load = 940 pounds), that would put you over the vehicle’s GVWR by some 33 pounds and the front tire’s max load limit would be over by a few pounds even at max tire pressure of 41psi.
8.) You need to change the tube every time you change a tube-type tire.
RW: We always recommend when fitting a new tire on a rim requiring a tube, a new tube should be fitted at the same time. Old tubes become stretched and if the old tube is fitted within a new tire, it can crease and fail due to thinning of the tube rubber over extended use. That said, if you are using aggressive knobby tires that you change out at roughly 1,500 miles, the tube may still be relatively fresh. After a thorough inspection, If there are no leaks, using it for another 1,500 miles or so should not be a problem.
9.) Direction markers are the only thing you need to look out for on the sidewall when changing tires.
RW: Not every tire manufacturer uses them, but you should also look out for a balance dot on the sidewall. All Dunlop motorcycle tires are visually inspected and run through a balance machine. The balance machine determines the low spot (light side) of the tire and marks it with a paint dot.
Assuming you are starting with a fairly well-balanced wheel, the valve stem position is the heaviest spot. You should install the tire with the balancing dot lined up with the valve stem. The light side of the tire gets matched with the heavy side of the wheel to ensure the tire can be balanced with the fewest amount of wheel weights possible. Also note that the balance dots are not universal in style among all motorcycle tire manufacturers.
10.) Just eyeing a tire is the best way to know when it’s worn out.
RW: We recommend motorcycle tires be replaced when only 2/32nds inch of tread is left. This is easy to check by using a penny, the top of Lincoln’s head is 2/32 of an inch. Or you can use the wear bars. All DOT tires, including knobbies, require wear bar indicators. This wear bar indicates the point the tire is legally worn out and required to be replaced. You can find them in several places around the tire in the tread area. On Dunlop tires, look at the sidewall near the shoulder for a small triangle, then look across the tread to find the small wear bar indicator within the tread grooves.
11.) Cleaners & protectants are safe to put on your tires.
RW: The best way to clean and refresh the look of your tires is to use a mild soap solution. Never use other cleaning or shining products which can damage the tires. Be especially careful not to use ArmorAll or any type of silicon spray on the tires, which will degrade the rubber and create an extremely slippery surface if it gets on the tread.
12.) An external plug is a safe way to permanently fix a tubeless tire puncture.
RW: For safety reasons, we never recommend repairing a tire from the outside or the use of any kind of spray products (e.g. Fix-a-Flat). However, when in remote areas, some riders may decide it is necessary to repair a tire with one of these methods in order to get out of a bad situation. If a rider decides to do this, they should consider it a temporary fix to get the bike home or to a repair shop right away. Reduce your speed and ride with caution until you can get a permanent repair from the inside of the tire using an internal combination plug-patch repair.
Not all punctures can be repaired though. Tires should not be repaired if any of the following conditions exist:
- A tire has been previously injected with a sealant/balancer.
- The puncture is larger than 6mm (1/4 inch) in diameter.
- The puncture is not perpendicular to the carcass.
- The puncture is in the tire sidewall.
- Separation of plies, tread separation or separation of any other components.
- Cut or broken ply cords.
- Broken or damaged bead wires.
- Cut or damaged chafers (bead area).
- Deterioration of the carcass inside the tire due to being run flat or underinflated.
- Cracks or other damage to the integrity of the inner liner.
- Excessive wear — tire should have at least 1/32 of an inch of tread depth, excluding tread-wear indicators.
- Cracks in sidewall or tread.
- Impact breaks, cuts, snags or gouges that penetrate the surface.
Also note, there should be no more than one repair in any quarter of the tire and no more than two repairs per tire. The wheel itself must be in good condition as well. Any cracked or bent wheel, however slight, may allow the loss of air and cause subsequent deflation of the tire. Following the repair, the valve assembly should be replaced, and the tire should be rebalanced. Do not exceed 50 mph for the first 24 hours after a tire repair, and the repaired tire should never be used at speeds over 75 mph.
Another way you can safely repair a puncture in a tubeless tire is to install a tube. However when you do this, the tube adds weight and friction that creates extra heat in the tire. Therefore, it is necessary to reduce the speed and load rating of the tire by one step. For example, a tire with a ‘T’ speed rating (max 118 mph) should be treated as an ‘S’ speed-rated tire (max 112 mph). Likewise, if the Load Index of the tire is a 57 rating (507 pounds), it goes down to a 56 rated tire (494 pounds).
Photos by Sam Bendall, Stephen Gregory and Jon Beck.
Author: Rob Dabney
Rob Dabney started a lifelong obsession with motorcycles at the age of 15 when he purchased his first bike – a 1982 Honda MB5. Through his 20’s and 30’s he competed in off-road desert races, including the Baja 250, 500 and 1000. Eventually, his proclivity for exploration led him to dual sport and adventure riding. Rob’s never-ending quest to discover what’s around the next bend has taken him on Adventures in Mexico, North Africa, Europe, and throughout the American West. As a moto journalist, he enjoys inspiring others to seek adventure across horizons both near and far.
Publisher – www.advpulse.com