Tire Size...Want to Make Sure

[1979GS750E]

For my 1979 GS750E, the book says...
Front Tire: 3.25H19-4PR
Back Tire: 4.00H18-4PR
I assume the following will be okay replacement sizes:
Front Tire: 100/90H-19
Back Tire: 120/90H-18
Any suggested brands/models? I'm not an aggressive rider...just a weekend rider...only 2500 miles/year.
I did try the search first, but still was not sure. Thanks for any help!

[Nessism]

Your sizes are correct.

Avon Roadrider is best performance tire value, Bridgestone Spitfire best value in a name brand, Chen Shin HiMax best value overall.

[Rudeman]

Those sizes will be fine. I like the Dunlop GT501's.

[almarconi]

Shinko Tourmaster, V rated and inexpensive.

[mwootto]

For my 1979 GS750E, the book says...
Front Tire: 3.25H19-4PR
Back Tire: 4.00H18-4PR
I assume the following will be okay replacement sizes:
Front Tire: 100/90H-19
Back Tire: 120/90H-18

How do you make these conversions?

[Steve]

How do you make these conversions?

25.4 millimeters to the inch.

3.25" x 25.4 = 82.55. Next size up is actually a 90, but most of us run a 100 to minimize the speedometer error.

4.00" x 25.4 = 101.6. Next size up is 110, but again, most will run a 120.

There is no advantage to going any larger than that, as the wider tire will get pinched into a tighter radius to fit the rim, and will actually give you a smaller contact patch.

.

[mwootto]

25.4 millimeters to the inch.

3.25" x 25.4 = 82.55. Next size up is actually a 90, but most of us run a 100 to minimize the speedometer error.

4.00" x 25.4 = 101.6. Next size up is 110, but again, most will run a 120.

.

Ah darn I just ordered tires for my gs425 90/90/18 in the front and 110/90/18 in the back. You think I should have bumped those up to 100 and 120 respectively?

[sharpy]

Ah darn I just ordered tires for my gs425 90/90/18 in the front and 110/90/18 in the back. You think I should have bumped those up to 100 and 120 respectively?

NO Leave them be

[mwootto]

NO Leave them be

haha thanks for the assuring response! i will