tire size

[catbed]

the tires i have on my bike are 16 years old and are in need of replacing. i checked pirelli's website and it said i need 130/90/17 in the back. according to the chart that was posted in this forum some time ago, it said to use 120 for 4.50. im guessing pirelli is right in telling me that i should get the 130s and not the 120s, but will it interfere with my swingarm/driveshaft?

[duaneage]

It's fit but it's 3/4 " taller, I had a bigger tire on mine when I got it and went with a IRC durotour that was the right size. I think the handling was better, the bike turned a few more revs at 60, and had a little better pickup, I noticed it right away as soon as I broke in the back tire a little \\/

[BassCliff]

They only go flat on the bottom

Hi Mr. catbed,

I use a 130 on the back of my bike. I think most folks here that ride our (850) bikes do. Yours will be OK. I think there's even room for a 140, but that would start to affect the handling negatively. I recommend the 130.


Thank you for your indulgence,

BassCliff

[catbed]

cool. thanks guys!

duneage: i would think that it would turn less revs because the circumference is bigger, no?

[duaneage]

cool. thanks guys!

duneage: i would think that it would turn less revs because the circumference is bigger, no?

Correct. It went up by about 250 at 60 mph. Not a big change but at higher speeds it was noticeable. It's hard to find smaller 17 inch rubber, most of the offerings are for crotch rockets and not really for our bikes My next tire might be a larger one just so I can try a set of maxxis tires, they have 130/17

[psyguy]

both 120/90 and 130/90 are ok
130/90 gives you 3-5 mm "clerance" on each side (thats Metzeler tyre)

[lurch12_2000]

the tires i have on my bike are 16 years old and are in need of replacing. i checked pirelli's website and it said i need 130/90/17 in the back. according to the chart that was posted in this forum some time ago, it said to use 120 for 4.50. im guessing pirelli is right in telling me that i should get the 130s and not the 120s, but will it interfere with my swingarm/driveshaft?

I keep scratching my head about this.
I have the 130/90-17 on the rear of my GS1100G and have no clearance problems. But I notice that the HiMaxx has (5.00-5.10-17) also stamped on the tire. Front is a HiMaxx 100/90-19 with (3.25-3.50) also stamped on the tire.
Most of the forum GS 850 and 1100 owners seem to be running the 130 but the 120 is what probably matches the 4.25-4.50 original stock tire size.
This has been debated many times before on the forum.
You should also pay attention to the rating as an H rated would be fine unless you run your bike in excess of 110 mph!

[duaneage]

Best thing to do is find someone on this site with a combination you're considering and ask them for measurements. Changing rubber is tough and expensive, going back to a different size is frustrating.

[catbed]

duneage again: so you have a tire bigger than 17 inches in there? pirelli has a 130/90/17, which is just wider than stock, so the revs wouldnt change would they? sorry its probably something really simple that im missing but i just woke up.

@ lurch: did you see any change in revs with different tires? not that you'll probably be able to remember when you changed the 120s off.

[duaneage]

It's the profile. the aspect ratio is 130 versus 120. That makes the tire a little taller and wider than the 120. I measured the 130 before I removed it while it was still mounted and inflated, then I measured the new tire. Even with more tread it was about 3/4" smaller overall than the bigger tire.

[catbed]

told you it was something simple. thanks :-D

[bwringer]

Every GS850G (& 1000G & 1100G) I've ever seen was wearing a 130/90-17, and I've never seen a clearance problem with that tire size. Take your pick of brands. (My recommendations for Pirelli's Sport Demons and Avon's AM26 RoadRiders are well documented, or Cheng Shin's HiMax are great tires for the money if you're pinching pennies.) I don't even know where you'd find a 120/90-17.

The GL and GK get 130/90-16 in the rear, of course.

Some owners have mistakenly mounted 110/90-19 up front, but handling is best with a 100/90-19. The wider tire is harder to stuff in there, slows down the steering, and makes the bike handle like a pig.

In letter sizes, these translate to MM90-19 front and MT90-17 (or 16) rear.

[chuckycheese]

Wow!

It's the profile. the aspect ratio is 130 versus 120. That makes the tire a little taller and wider than the 120. I measured the 130 before I removed it while it was still mounted and inflated, then I measured the new tire. Even with more tread it was about 3/4" smaller overall than the bigger tire.

I had no idea that would be the case! That's good information to know.

[lurch12_2000]

@ lurch: did you see any change in revs with different tires? not that you'll probably be able to remember when you changed the 120s off.

My bike had a well worn Dunlop 130/90-17 and I replaced it with the HiMax 130/90-17 rear. So I can't compare any rev difference, but the new tire handles and rides nice.

[psyguy]

I had no idea that would be the case! That's good information to know.

120/90 and 130/90 differ exactly 11mm in side profile
this is under half inch, not 3/4
however, different brands have different threads so that may add to (or take from) the difference

130mm is just over 5"
the exact metric size for the 4.50" tyre would be 114mm (not that they come in this size though)