Help with tire sizes?

[NBraun]

I have a gs 750 with the original tire sizes being 3.25-19 and 4-18. What are these tires sizes with the aspect ratio? I'm looking at the shinko 712's and what are the best options for tire size?

 

[teddpage]

The rim width is the biggest factor here on how wide of a tire you can run.
Those tires are equivalent to approx a 90/90 front and 110/90 rear...but each manufacturer is different in what size belongs on which rim.

 

[Big R]

Tedd is right about the rim width. It's usually stamped by the valve stem and will look something like:

19*1.85

Check your wheels and come back.

 

[NBraun]

Well right now I'm nowhere near my rims, but thanks for the help! I ended up just ordering 100/90 for the front and an 110/90 for the rear. Hopefully they'll work.

 

[mydlyfkryzis]

Here's a chart of conversions:

http://www.kgmotorcycletires.com/size_conversion_charts.htm

A 110/90 means a 110mm section width - about 4.33 inches, which really is about a 4.00 inch tire. The section width was/is a little odd, as even on car tires, the section width of 2 tires with the same size listed on the sidewall, will have different widths anyway. But still close to the size marked.

The older tires were generally somewhere between an 80 and 90% height.

So a 4.00-18 tire is now a 110/90 - 18 tire

The charts show the rest.

More modern bikes, like my NH750, use a 70% height tire, which has smaller height sidewalls then a tire with a 90% height.

Cars go as low as 40% height. Those tires look like they have nearly no sidewall at all.

Hope this helps