Anyone running 120/90/18 rear tire

[graham heise]

I have an option to buy some new metzeler lasertecs for a heavely discounted price. 90/90/18 front and 120/90/18 rear. Just questioning the rear as tje stock tyre is 110/19/18. Anyone running a 120/90/18? Are there any issues?


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[silverstrom]

Stock rear is 110/80-18

The difference between that and your 120/90-18 is 40 mm of total height top to bottom. You'll notice it, but it won't hurt. I always used a 120/80-18 which was 24 mm total height taller.

[brrrappp]

I ran that size a long time ago and it was fine. My favorite back in the 80"s was a Michelin 130/70/18 rear.

Lessons learned if you are interested.....
the first number is the width. the second number is the percentage of height relative to width.
110/90 = 99mm that means the tire is 110mm wide and about 99mm high
120/90 = 108mm and that will be a little less than 1/2 inch taller than the original size. That might be enough to put slightly more weight onto the front but most people are not going to notice the difference.

The more popular size for the stock rear rim is 120/80 = 96mm high

Other issues are tire weight and the general shape of the tire itself.
Since the rim stays the same width, the problem with going much wider than stock is that the footprint of the tire actually gets more angular as tire width increases and that reduces the contact patch. It can also make your bike feel like it is falling into turns.

Some tires are designed with a high center. These tires feel like they want to turn all time and tend to give that same falling into turns feel while maintaining good stability through the turn. Other tires are more gently rounded from side to side and give the rider more confidence by being less responsive to rider input.

When you go bigger on the front you immediately notice the steering becomes heavier. This can be caused by both the increased gyro effect of more tire weight taller circumference and the increased contact patch.
If you go too big the the tire can loose traction rather abruptly as you may turn-in more forcefully and have less contact patch at lean angle.

[brrrappp]

Silverstrom is correct the original OEM was 110/80 and that is 88mm tall (sidewall).

OEM 110/80 = 88mm sidewall
120/90 108mm sidewall 20mm = about 3/4 inch still not a huge difference in ride height.

[(F5)]

I had a 120 Metzler back in the day. It was too big and made it wobble plus couldn't get near the edges as deformed. So e tyres seem to cope better, old michi slicks were valanced in to be wider on skinny rim.

I ended up running a 130 but I fit an FZ400 rear rim that had same spoke pattern as my F2 but needed machining disc mount inwards.

[mosquito13]

I wanted larger softer tires, so laced up wider alloy rims. Put a 1.85 on front and going to a 2.15 on rear. Tires sit better on wider rims. Had to do some trimming on the chain guard for fitment of wider tire & upgraded shocks. Pic is on steelie notice the way the tire is pulled in when seated on the stock steel 1.85 rim.