If you want to open a huge debate on any motorcycle forum – start off the topic thread with tire choices (or soft vs hard panniers). Every seasoned rider has an opinion and every novice rider has a story they have heard.
When I began my adventure ride to South America, I searched and searched online forums and blog pages to decipher the optimal tire for the trip. What I found, was useless. Dozens of different opinions and no clear answer.
After two years of riding, frankly I still do not have one answer, since I learned there is no ‘best’ tire for the adventure rider. And no one tire performs the same for all bikes, and no one tire performs the same twice for the same same rider due to the different conditions on each route. So, I limit this write-up to my experience and considerations, and leave the rest up to you.
First: My experiences encompass 108,000 miles, across 6 continents, and every road surface imaginable. That does not make the tire puzzle any clearer, since each tire I have tried has straddled more than one condition. My motorcycle is a Suzuki V-Strom 650, with tubeless tires. Front tire size 110/80R19, Rear 150/70R17. Those are important, and some terminology will help explain why.
Tubeless versus Tubed Tires
Tube-and-tire systems were the norm until the past decade. Spoked while rims often required a tubed tire (except for BMWs). And many off-road adventures in less developed parts of the world are better tackled with a tube and a patch kit. Tubes should be replaced at the same time as a new tire.
So why do many modern bikes have tubeless tires? One cynical answer is that it is cheaper for manufacturers. But they also run cooler (less friction) and that performance difference statistically leads to longer life for the tire. It can also have the benefit of using a basic puncture kit to plug a nail hole, rather than removing the wheel on a tube tire and patching / replacing the tube.
I have heard to some riding adding a tube in a tubeless tire. If your rim is in normal condition that is not only unnecessary, but the increased heat will impact tire life (but it otherwise will not cause a problem).
For my bike, the recommended rear tire is 150/70R17. The 150 means the width is 150 mm. Wider tires means more contact with the road – more friction than a similar dual-sport bike with slimmer tires. This mainly impact fuel economy. The 70 is the aspect ratio, in other words the height is equal to 70% of the tire’s width. A bigger ratio means bigger tire sidewalls. At the end you see the construction code: if you see an “R” that means layers run radially across the tire. “B” means blended tires. And last is the wheel diameter. My rear tire fits a 17-inch wheel.
Dual-sport tires may be designated as 90/10, 80/20, 50/50, etc. What does that mean? Generally it indicated the traction the tire will provide on dirt versus pavement. Less aggressive and the tire will have more longevity and do better on pavement. More aggressive and the tire will grip sand and mud. Large knobby tires will grab at the gravel, but the will wear quickly on tarmac and squirm on blacktop. Less knobs, and more channels, will funnel rain through the groves and away from the center, leading to better traction on wet curvy roads.
Each tire is outfitted with a tread groove depth indicator. For most tires 0.8 mm (about 1/32”) is considered the manufacturer’s minimum safe tread depth. But more goes into ensure a safe tire. Especially with knobby tires, there can be uneven wear (flat spots) and then cracks around the knobs. Gashes in the rubber can be the starting point for further issues if the tire heats up.
Each tire has its manufacturer recommended inflation pressure. You will want to check the tire when cold, and I usually check mine in the morning at the first gas station before the inside really heats up. Higher pressure will inflate the tire and subtly decrease the rubber contact with the road. Which, as noted above, when slimmer leads to less friction, better fuel economy, and more longevity. But on gravel, a highly inflated tire will not be your friend. An under-inflated tire is far better, since then more rubber will come in contact with the surface and allow the bike to have increased grip. Altitude will affect pressure (since at higher elevation, the outside air pressure drops), but keeping the cold tire at the manufacturer specified pressure will be more of a challenge when tackling major elevation changes in a single day (since then you lose the ability to measure the tire at cold unless you rest the bike for a while).
Over the course of two years I have observed a lot of tire choices on many many bikes. I am only going to comment impartially on those. For me, I have used 6 major tires:
Other Considerations for the Adventure Road
So, when do you replace a tire? Do you carry tires? Mail order? Install tires yourself to save money? A lot of calculus goes into managing your tires on a long-term road trip, where you no longer can rely on your friendly local dealer or even trust that you are at a stable address to receive a mail-order shipment.
Often riders are trying to contain costs. Tubed tire installed is a no-brainer for most of those riders. Tubeless tires are a little more challenging to ensure a solid bead is achieved, but one good approach is to get tires mailed to a friend or a motorcycling acquaintance at the lowest possible cost, then just take them to a local tire shop with a bead-breaker and install them back onto your bike yourself. Many times riders fail to anticipate when they will need new tires, and find it tough to get high quality tires outside Western countries at affordable prices.
When I notice my depth indicator is close, and flat spots appear, I start hunting for tire stores within the next 1,000 miles. In the United States they are easy to find, but difficult to pin down to have provide mechanic time. Outside the United States, I concentrate on the big cities, and find contact information for any well-rated shop. In Latin America, I would email shop owners in Spanish since I would struggle to explain my request over the phone.
Regardless of where I went in the world – and I changed tires in the US, Canada, Peru, South Africa, Germany and Dubai – I never had any real problems and there always seemed to be later options when I thought there would be none. In Africa for instance I found a great shop in Cape Town (The Flying Brick) who figured out how to mail tires from South Africa to most places around the continent regardless of import laws. However, do not expect to find great tire options in wide swaths of the developing world. I carried a pair of tires from Bulgaria across to the Middle East to get the most from my existing set, but still have a fallback if either had an issue. I would rarely recommend carrying tires due to today’s shipping options unless going to countries with strict import laws. Adventure motorcycling is world-wide and even if you get “stranded” for a week to have a tire shipped to you, don't get burned up - just smile and enjoy the wait.