tire sizes

seamax · April 20, 2011, 12:18:43 PM

My '79 GS425 has the following tire size; front 3:60- 18", the rear 4:10-18". What does that translate into lamen tire sizes xxx/xx?

Big Rich · April 20, 2011, 12:38:47 PM

Closest would be about 90/90 and 100/90, but what you need to know are the widths of the wheel. It should be stamped on it somewhere along the outer lip or around the hub. Once you have the rim width, check out this chart:

http://www.dropbears.com/u/utilities/tyrerim.htm

burning1 · April 20, 2011, 02:25:43 PM

Yeah. Sounds like he's running 18 inch rims. Rim width would help in determining ideal tire size.

Big Rich · April 20, 2011, 04:46:47 PM

Seamax, if those wheels are what I'm thinking, the front is 1.6*18 and the rear is 1.85*18. You will have a hard time finding a tire for the front that wont look like a bicycle tire. The good thing is that you can upgrade to a "normal" GS450 19" wheel that is 1.85" wide.

You might have to mess with the fender to get it to fit- but just wanted to let you know you have the option.

seamax · April 20, 2011, 08:22:09 PM

Just took a closer look at the tires. Front tire is 3.00-18 and the rear is 3.50/3.75H18. The wheels are spoked and there are no numbers as far as I can see on them or the hub. The bike is a 1979 GS425N. I believe the N model has the spoked wheels while the EN and the LN model has the mag wheels.

I like the spoked wheels and want to keep them but put some new sporty tires on for this cafe build.

Here's some pics of the difference in models.

http://www.cyclechaos.com/wiki/Suzuki_GS425

Big Rich · April 20, 2011, 11:02:24 PM

Oops- I assumed mags. Probably the same sizes I mentioned earlier though. Since it's not stamped on them, the only sure way is to remove the tire and measure between the beads.

With spoked wheels, that opens up a lot of options. 36 hole rims from a disc brake front end are easy to find.

seamax · April 21, 2011, 07:05:55 AM

Quote from: Big Rich on April 20, 2011, 11:02:24 PM
Oops- I assumed mags. Probably the same sizes I mentioned earlier though. Since it's not stamped on them, the only sure way is to remove the tire and measure between the beads.

With spoked wheels, that opens up a lot of options. 36 hole rims from a disc brake front end are easy to find.

Rich, I have disk brake front so I happy with that and I love the hub brake rear. I'm going to take the wheels off soon to repaint the rim spokes and hub black and then I'll look into the tires. I have clubman bars and seat coming for it.

Since the rims and the tires are not very wide you think I can change the tires myself? I would think they would be easier to break then a sportsbike tire.

Big Rich · April 22, 2011, 02:07:38 PM

I mentioned a disc brake wheel only because spoked rims are drilled different for drum and disc brakes.

I hate changing tires- so I became friends with the local tire guy. He pulls old tires off for free and doesn't charge me much to install the new ones. Just because they are skinny, doesn't mean they are easy.

One more thing- your front rotor is solid, correct? The later model slotted rotors should bolt right up. Just make sure the rotor is for a front wheel.

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tire sizes