What size of tire?

[JessC]

Hi,
I'm working on my 1975 GT550 and it needs a new rear tire one that is on it is a 4.25X18 and is totally dry rotted but holds air. What should I use to replace it with a equal size in the metric size? I will use the bike for highway rides. I need some idea's
Thanks,
Jess

[dorT500]

............. it needs a new rear tire one that is on it is a 4.25X18

Just passing through and saw no other replies for a couple or three days. I offer this for what it is worth.......


Stock rear rim? If so, just for the record, the 4.25 rear on there is not the stock tire size.

Stock rear rim size is 2.158 inches x 18...... Stock tire size 4.00 inches x 18

Stock front rim is 1.85 inches x 19 ....... 3.25 x 19

Calls for tires to be a matched set, that is, the tread design should be the same front and back.

You might look over this including the allowable tire size on a specific rim size chart.


https://www.denniskirk.com/learn/tire-sizes-explained" onclick="window.open(this.href);return false;"


search.php?keywords=Dunlop&terms=all&au ... mit=Search" onclick="window.open(this.href);return false;"

search.php?keywords=Shinko&terms=all&au ... mit=Search" onclick="window.open(this.href);return false;"

The stock rim sizes and tires are the same for my T500. I've used Dunlop 404's for years but have used Shinko 712's more recently. With both, I have to remove/move the main bracket for the front fender or deflate the tire a bit to pull the wheel out.

[jabcb]

What front tire do you have? Take a look at the date code on the front tire. Might be time to change both tires.

As dorT500 said, the stock rear tire was 4.00x18. Back in the day, 4.25/85x18 was a performance-sized tire. I didn’t even know that size existed prior to seeing it mentioned on the SmokeRiders website.

Avon RoadRiders are a popular choice. They are available in the original stock sizes. The choices in modern metric sizes are limited because of the narrow rims.

[dorT500]