New tires

[ZombiePotatoSalad]

Where a good place I can find tires to replace the ones I have? The tires I have are dryrotted, and the rear tire goes flat within 10 minutes.
I was checking out BikeBandit, but they only seem to have tires that are compatible with the front rim in their sets. I'm having difficulty finding a tire that fits the back rim. Also, I live in Davenport, Iowa. What would you experienced riders recommend?

[Steve]

Can you give us a clue what sizes you need?

Not all vendors carry all sizes.

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[ZombiePotatoSalad]

Can you give us a clue what sizes you need?

Not all vendors carry all sizes.

.

The front tire is 3.25H19-4PR
The rear tire is 4.50H17-4PR.

Will I have to find the closest match possible?
I've only been able to find the front ones with that specific size. I tried directly searching for the rear tire number, nothing comes up.

[Steve]

You should be aware that the rear tire is several sizes oversize.

The parts fiche shows a 3.25 for the front and a 3.75 for the rear. In today's metric sizing, that would translate to 82.55 and 95.25. Since tires don't come in those exact sizes, we will upsize those to 90 on the front and 100 on the rear. Might actually go to 110 on the rear. Your 4.50 tire converts to 114.3mm, the next size up would be 120. I'm not sure the rim is wide enough to support that wide a tire.

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[Big T]

BikeBandit is expensive
There's a number of places for tires, try Dennis Kirk, or Rocky Mt ATV or RevZilla or Motorsport

Try Shinkos or Avon Roadriders

[ZombiePotatoSalad]

You should be aware that the rear tire is several sizes oversize.

The parts fiche shows a 3.25 for the front and a 3.75 for the rear. In today's metric sizing, that would translate to 82.55 and 95.25. Since tires don't come in those exact sizes, we will upsize those to 90 on the front and 100 on the rear. Might actually go to 110 on the rear. Your 4.50 tire converts to 114.3mm, the next size up would be 120. I'm not sure the rim is wide enough to support that wide a tire.

.

What size would I be looking for? There are other letters and numbers. For example, there's a 110 80-19 and 110 90-19. Also, it seems that many are out of stock.

How about these? https://www.denniskirk.com/irc/gs-11...s=5497&rs=5493

[hank2]

Just to be sure, your bike is a GS550e, right? Parts fiche shows only a GS550L for '80 model year. GS550e was '79. Unless you happen to have L model?

Like Steve mentioned, on a GS550e, the rear wheel size is 2.15, 18 inch, not 17 inch. L model has a 2.5-17 inch. Front wheel is a very skinny 1.85. If it is an 18 inch rear wheel , no problem with a 110/90/18 tire on a 2.15. If you have an L with a 2.5x17 inch rear, then a 120/90/17. For the front, a 100/90/19 would be OK. There are 90/90/19 tires, but mostly knobbies or dual sport tires.

FWIW, I have used many sets of both Bridgestone S11 Spitfires and BT45's on another bike in the past. I mention that because for whatever reason, the BT45 model is quite noticeably skinnier in the same tire size than the S11's, or many other makes, with a more pointed contact area. If you do have a 19 inch front and an 18 inch rear, you can get the Bridgestone BT45 matched set in 100/90/19 front and 110/90/18 rear in a set. Or 100/90/19 front, 120/90/17 rear on the L model.

I've used mostly Rocky ATV for tires in more recent years. They seem to carry a wider selection of sizes and models than many. Many dealers and shops closed in my area and none remaining will mount carry in wheels and tires. When they did it was up to $60 a wheel labor. Buying tires from them on install is full boat retail, about 2 to 3 times the price of mail order.

[ZombiePotatoSalad]

@hank2 Yes, it was made in November of 1979, so the start of the 1980 model year.

[Steve]

Hank brings up a good point between the E bikes and the L bikes. I seem to recall that many (most?) 550s have the "E" on the VIN tag. Yes, even the L models.

So, ... for clarification, ... is the front axle inline with the forks or is it stuck in front of them?

Does it look like this:


or like this?


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[ZombiePotatoSalad]

It's inline, it's an E.IMG_20190713_191728.jpg

[Steve]

In that case, I would look for something in a 110 rear, no more than a 120. Stick with a /90 series, that means that your tire size would be 110/90-18 or 120/90-18.

For the front, look for a 90/90-19. There is a little more selection with a 100/90-19, but that is almost too wide a tire for the rim.

Unlike cars, putting a wider tire on a motorcycle rim does NOT put more rubber on the road. Since you would be pinching a round-ish tire into a tighter profile, you will actually REDUCE the size of the contact patch.

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[Nessism]

I'd use 100/90-19 front and 120/90-17 rear. Avon Roadriders if you can afford them. American Moto Tire is a great source w/free shipping.

[LAB3]

Try chapmoto.com they have the lowest prices I've come across and went above and beyond making things right on a botched order a couple years ago.

[ZombiePotatoSalad]

Thanks for all your help, everyone. I may be a month or two away from actually buying tires, but it will be good to know exactly what I have to buy so I will know how much money I need.

[ZombiePotatoSalad]

In that case, I would look for something in a 110 rear, no more than a 120. Stick with a /90 series, that means that your tire size would be 110/90-18 or 120/90-18.

For the front, look for a 90/90-19. There is a little more selection with a 100/90-19, but that is almost too wide a tire for the rim.

Unlike cars, putting a wider tire on a motorcycle rim does NOT put more rubber on the road. Since you would be pinching a round-ish tire into a tighter profile, you will actually REDUCE the size of the contact patch.

.

For the rear tire, 19 or 18? If that's the rim size, it seems odd that the front would be 19 and the rear 18.