The front tire of my TDM900 was already 17 inches when purchased. (Dunlop SPORTMAX ROADSMART Ⅲ, 120/70ZR17MC (58W)）But I wanted to know the original riding taste of TDM, so I decided to go back to the original 18 inch.

This time I will install 120/70ZR18 of Bridgestone Battlax Sport Touring T31.

As you can see, there is a gap between the tire and the fender for 17 inch.

The difference in outer diameter between 17 and 18 inches. According to the calculation, the outer circumference of 120/70R17 is 599.8mm and 625.2mm of 120/70R18. The difference is 25.4mm, but it looks like a big difference. Also, the radius of the 18-inch model is tighter, and it looks thinner.

Side view after installing 18 inch. There is no longer a gap in the front fender.

First, when , the volume around the front is completely different. It’s like a bigger bike. The bigger tires raise the front and give you a better view. In addition, the gyro effect of the front wheels, caster angle and trail amount have increased, clearly improving straight-line stability.

Compared to the 17-inch front, I could turn corners naturally without getting nervous. When I used 17-inch, there were times when it would strangely cut into the inside, so this strange habit has been removed and it became very easy to ride.

I feel more secure when running down hairpins with grooves like this.

With poor road conditions, the front wheel is less likely to move wildly making it more stable than a 17-inch wheel.

I felt that this was the original riding performance of the TDM, which was originally designed with an 18-inch front. I think 17-inch tires have the advantage of being able to choose from many tires, but I felt that 18-inch tires were better suited to my riding style. The 18-inch front wheel is really comfortable to ride.

It would probably be easier if it were 19 inches or 21 inches, but I think the exhilaration would be diminished if it were too generous, so in a sense, 18 inches may be the perfect size.

Depending on how you ride, I think 17 inches may be better, so please note that this is just my personal opinion.