120/90 versus 110/90

The specs call for a 110/90-18 rear tire, but I like the 120/90-18 because it is bigger. Any comments? My bike already handles like crap and I will scrap the bigger tire idea if it will further degrade the handling. Anyone know the pro and cons of going bigger on the rear tire?

I am running a 120/90 18 on my Z1 and have plenty of room before hitting chain or swingarm. You shouldn't have a problem at all. If the rim was wider I could go bigger before rubbing the tire

These bikes don't handle like a modern bike but going up a size or two wont hurt anything

I run a 130 80 18 on my 77 1000. Have about a half an inch between the tire and the chain.

You can search this as I know its been covered many, many times before but short answer....

The wider the tire is on the same width rim, the more rounder the profile becomes and the less contact patch you will have.

Later, Doug

Where do the specs call for a 110/90-18? Nowhere I've ever read. 4.00-18 is stock and no that is *not* a 110/90-18, not even close. Run a 120/90-18 for all practical purposes, but it will be too wide for the rim. Run a 130/90-18 and it is way to big for the rim. Here's pretty much the rundown on tires.
110/90-18-basically correct width, but low profile=reject
120/90-18-basically the right diameter but too wide=usable, but it isn't perfect for the wheel size.
130/90-18-much too wide for 2.15" wheel=reject
4.00-18-correct tire that works and looks correct-usable

RonKZ650 wrote:

Where do the specs call for a 110/90-18? Nowhere I've ever read. 4.00-18 is stock and no that is *not* a 110/90-18, not even close. Run a 120/90-18 for all practical purposes, but it will be too wide for the rim. Run a 130/90-18 and it is way to big for the rim. Here's pretty much the rundown on tires.
110/90-18-basically correct width, but low profile=reject
120/90-18-basically the right diameter but too wide=usable, but it isn't perfect for the wheel size.
130/90-18-much too wide for 2.15" wheel=reject
4.00-18-correct tire that works and looks correct-usable

I run a 130 80 18 not a 130 90 18

I've run 130's and 120's on my KZ650C1. The 130's are ok (hard as hell to mount), but I prefer the 120 as it doesn't distort the profile. Forget 110, you may as well stick a bicycle tire on it. Ed

dragnkaw1428 wrote:

RonKZ650 wrote:

Where do the specs call for a 110/90-18? Nowhere I've ever read. 4.00-18 is stock and no that is *not* a 110/90-18, not even close. Run a 120/90-18 for all practical purposes, but it will be too wide for the rim. Run a 130/90-18 and it is way to big for the rim. Here's pretty much the rundown on tires.
110/90-18-basically correct width, but low profile=reject
120/90-18-basically the right diameter but too wide=usable, but it isn't perfect for the wheel size.
130/90-18-much too wide for 2.15" wheel=reject
4.00-18-correct tire that works and looks correct-usable

I run a 130 80 18 not a 130 90 18

Don't matter if it's a 130/90-18 or a 130/20-18. 130 is still too wide to work with a 2.15" rim. I've run 120/90-18 for 200,000 miles or more, 130/90-18 a couple times=reject, 110/90-18 once=major reject. Stay 4.00-18 or if absolutely can't stand staying stock, stay 120/90-18 but still too wide for a 2.15" wheel. I have nothing against wide tires, get a 2.5"-3" wheel and go to town, but 2.15" no good trying to go wide.

Thanks for the feedback. I will go with 120/90-18 as that seems to be the consensus. And I like the look of a fatter tire.