Dunlop D404 Tires | Gear Review

Gear Lab | Dunlop D404 Tires
The Author’s 2006 Triumph T100 Bonneville, fitted with D404’s. Photo by Clement Salvadori

I’ve worn out a lot of tires in the last 66 years of riding, and I have no real memory or record of what I used when and on what bike. I am sure I had a lot of Dunlops, as they have been around a long time. Back in the late 1880s, John Boyd Dunlop made the first practical pneumatic tire for bicycles, which were a lot more comfortable to ride than bikes with solid rubber tires. In 1901, he started the Dunlop Rubber Company, which now belongs to Sumitomo Rubber Industries. 

Dunlop describes these D404s as fitting “standard” motorcycles, and they don’t get much more standard than my 2006 Triumph T100 Bonneville. I call these tires universal-use, reasonably good at everything, from wet pavement to dirt roads. My Bonnie is pretty much an all-around, local-use machine, happy with doing errands or a 200-mile day. Around here we do have all sorts of roads, from smooth asphalt to pothole specials, and lots of good dirt roads, from Gillis Canyon to Cypress Mountain. 

I find the tread to be pleasingly chunky, and Dunlop says the design enhances wet grip and water evacuation. Since we are in a drought here in our part of California, I can’t attest to those functions. The off-set center groove is intended to improve straight-line stability, and I can’t fault that, as on some deserted back roads I just might exceed the speed limit. 

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The carcass is a bias-ply design, which means that the fiber belts, or plies, go from side to side at an angle, hence a bias. About half the tire is made of rubber, both natural and synthetic, and the rest is mainly the fabric body plies that go between those wire bead bundles that keep the tire properly attached to the wheel. Dunlop says this compound will give excellent mileage; you are reading this report after a mere 800 miles, and I’ll let you know when I will need a new rear tire. 

Speaking of which, the official Triumph size for my ’06 rear wheel is 130/80-17, with that 80 being the aspect ratio. And just what is the aspect ratio? The height of the sidewall expressed as a percentage of the width of the tire. The closest the D404 comes is a 130/90-17, which means the tire will be a smidge taller. 

New tires are on, new inner tubes are in. Picked up the bike late in the afternoon, and after a relatively calm 40-mile break-in, went home and had a glass of wine. In the morning, I checked that the tires were at proper pressures, and then went with a friend to do a run over Rossi’s Driveway, as we call the eight miles of Route 229 going from Route 58 to Creston. Guilty fun, with just one car on the road, quickly dispatched. 

MSRP on these tires are $118.81 front, $132.01 rear, but if you shop around, you will pay less. 

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For more information: visit dunlopmotorcycletires.com

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