I asked GS1200SS and Inazuma 1200 owners about “not having tire options,” and
at first I didn’t understand what they meant…
The stock rear wheel is 5.5-17, which is 180/55-17, so there are plenty of options, right?
But since the stock size is 170/60-17, that’s the issue! Ah, I got it.
Tire size is selected by matching it with the wheel rim width (listed as standard rim width).
Tire sizes are designed for specific standard rim widths.
Now look at the image above.
For example, with a 4.50 standard rim width,
160/60-17, 160/70-17, and 170/60-17 are available options.
• 160/60-17 and 160/70-17 are designed for 4.50 rim width, but can be used up to 4.50-5.00 rim width.
• 170/60-17 is designed for 4.50 rim width, but can be used up to 4.50-5.50 rim width.
That’s how it works.
Next, 180/55-17 is designed for 5.50 rim width, but can be used up to 5.50-6.00 rim width.
That’s how the specification reads. Different manufacturers may vary, so it’s best to always check.
So why do the GS1200SS and Inazuma 1200 use 170/60-17?
• They wanted to maintain chain line clearance?
• They aimed for nimble handling? Though nowadays that would mean a bulging tire…
These are possibilities.
I’m a bit fuzzy on this, but I recall that back in the 20th century, a 5.50-inch rim was a 170 size.
The XJR1200 also came stock with 170/60-17, so I think that’s right.
Then as time went on and we entered the 21st century, I think 5.50-inch rims were changed to 180 size.
To summarize: tire manufacturers recommend 180 size for 5.50 rims by design. However, you need to check ride height and chain line before installing.
And if you put a 170 size on a 5.50 rim, the tire will bulge quite a bit. You’ll reach the edges quickly, which is nice, but capacity is lower and handling feels more sluggish—or mellow, to put it kindly.
*Tire selection is for reference only; use your own judgment!
*I think tire manufacturers only list whether they offer 170/60-17 based on stock specifications.
I had three bikes to compare, so I took some light measurements.
GS1200SS-2
• Marchesini 5.50-17
• Pirelli Rosso Corsa 2, 180/55-17
• Actual width 178 mm
• Tire-to-chain distance approximately 10 mm
GS1200SS- 1
• Stock 5.50-17
• MEZ Sportec M5, 180/55-17
• Actual width 179 mm
• Tire-to-chain distance approximately 10 mm
Inazuma 1200
• Stock 5.50-17
• Dunlop RoadSport 170/60-17
• Actual width 175 mm
• Tire-to-chain distance approximately 10 mm
From what I can see, fitting a 180/55-17 shouldn’t cause chain line issues. Compared to 170/60-17, the overall diameter is slightly smaller (lower), so if that bothers you, you could compensate with a ride height adjustment.
If you can’t find a 170/60-17 tire, use this as a reference. (At your own risk.)
