1979 gs850 rear tire

[hadaveha]

I'm replacing the rear tire on my 1979 850g just wondering whats the widest tire anyone has fitted on there 850, I would love to push it as wide as possible

[Steve]

There is no point in going "as wide as possible". The wheel will only properly support a certain size tire and the swing arm will limit the width, as well. The largest tire you can safely run is a 130/90-17.

If you just HAVE to have the absolutely widest tire for a "look", you have the wrong bike.

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[bwringer]

Yep, 130/90-17.

Any wider and the tire hits the swingarm on the left. It's reaaaaal close as it is.

If you want that "phat meats" look on a GS, you'll need to start with a chain drive bike, assorted spare parts from later bikes, a welder, a sharp pencil, a lathe, some fabrication and engineering skills, etc...

[hadaveha]

I wasn’t really meaning anything crazy wide, I just wanted to know the widest standard size

[Steve]

That might be, but the way you worded the original post just sounded like too many others that ask "how can I fit a 220 tire on my bike?" or some such nonsense. We then have to try (sometimes successfully) to convince them that a wide tire on a narrow wheel simply won't work, as it actually puts less rubber on the road. And you have the added luxury of a hollow swingarm that contains a driveshaft, so there are basically no modifications possible there.

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[bwringer]

The original rear tire size was 4.50-17. Very few street tires are made in those old inch size designations nowadays, and 4.50-17 doesn't even exist anymore, so you have to convert.

The closest modern tire size is something like 120/90-17 (the math works out to a width of about 115, actually). The problem is that there are only two companies making 120/90-17 in a rear tire, but there are lots of fantastic options in 130/90-17.

So that's what everyone runs on their GS850G. It's a squidge wider than the original, but works extremely well. But a 130/90-17 runs pretty much as close as you can get to the swingarm on the left -- a 140 definitely wouldn't work.

In case you're wondering, up front you want a 100/90-19. You can sort of make a 110 fit (most hang up on the fender bolts), but it really screws up the handling.

GS850s handle pretty dang well with the correct tire sizes.

[Steve]

Picture is nice, Brian, but you really need to post a video, if possible.

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[tas850g]

I'm replacing the rear tire on my 1979 850g just wondering whats the widest tire anyone has fitted on there 850, I would love to push it as wide as possible

I want a 160 on my 850 so I can do this on it

[bwringer]

Picture is nice, Brian, but you really need to post a video, if possible.

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Oh, all right. Turn your speakers down... The fisheye lens sort of flattens out the lean angles.

[bwringer]

I want a 160 on my 850 so I can do this on it

You can do that with a 130...

[Buffalo Bill]

The original rear tire size was 4.50-17. Very few street tires are made in those old inch size designations nowadays, and 4.50-17 doesn't even exist anymore, so you have to convert.

The closest modern tire size is something like 120/90-17 (the math works out to a width of about 115, actually). The problem is that there are only two companies making 120/90-17 in a rear tire, but there are lots of fantastic options in 130/90-17.

So that's what everyone runs on their GS850G. It's a squidge wider than the original, but works extremely well. But a 130/90-17 runs pretty much as close as you can get to the swingarm on the left -- a 140 definitely wouldn't work.

In case you're wondering, up front you want a 100/90-19. You can sort of make a 110 fit (most hang up on the fender bolts), but it really screws up the handling.

GS850s handle pretty dang well with the correct tire sizes.

All true. What is very frustrating is using the tire selection guides based on bike make and model.
I'm getting grossly misguided when I check in 1982 Suzuki GS1100G, Rear Tire. Forced to choose between Avon or Bridgestone 120/80-17, or weird dead end choices. Bikebandit or J&P Cycles.

[850 Combat]

The original size provides slightly more nuetral handling. I'm having to buy a new set for mt 1000G in Maine.