Front Tire 120/60 vs 120/70

[Nick Howe]

How would a 120/60/17 do on the front? Versus a 120/70
Im thinking Pirelli Rosso II for both front and rear
http://www.motorcycle-superstore.com/1/ ... -Tire.aspx
Im thinking:
Cons - screwed up speedo, harsher ride?
Pros - quicker steering, less tire flex while leaned over

Any feedback would be great, Im running a 180/55/17 on an srad gixxer swinger so I'm thinking 110 up front wouldnt be a good fit.

Also, I really want to do the r6 shock swap but cant get ahold of reelrazr....

[crowe]

depends on what you want! if you need the bike to handle properly then fit the factory spec (generaly). if you dont want handling fit what you want. IMO fitting missmatched sized tyres is generally not a good idea because you take a bike that will go round corners and turn it into one that wont.

when i bought my EXUP1000 some moron had put a 190 section rear and 130 front on it and it handled like a ship! put the 180/120 on and it made a huge diference.

it all about profile shape and size of contact patch without the front fighting against the rear for tip in speed or stability.

[DonTZ125]

So long as the tire profile is reasonably round, steering deftness lost to a bigger front tire can generally be recovered by raising the forks / dropping the front end to return to the nominal rake and trail numbers; it may be necessary to steepen a bit past 'stock' to restore the original handling. Small adjustments, here - 1/8" to 1/4" at a time, then go for a test ride. Lather rinse repeat, and take notes!

[Nick Howe]

i have two fzr6's and i've always run 120s, but always a 120/70
i know the 110 is better for turn in, but I generally would rather muscle the bike over than lose grip in the middle of the corner
(im a 6'5" and 210lbs)
*my bad, i messed up the title originally, i meant 120/60 vs 120/70

[pefrey]

Racers go with the 120/70 because the higher profile has more flex (less stiff) and therefore provides more feel / feedback to the rider.

[Nick Howe]

Racers go with the 120/70 because the higher profile has more flex (less stiff) and therefore provides more feel / feedback to the rider.

Reeeaaallly, ok, on my four wheeled beemer, more sidewall meant the car would move around a lot on the stock rim/tires with big sidewalls but hunkered down and found more grip on bigger rims with less sidewall and less flex
-Buuut bikes are different and I bow to your knowledge , thanks for the response!

[pefrey]

Yup, cars are opposite in this respect. Of couse that does not mean a 120/80 front tire would be even better. You'd probably have too much flex and everything would get wobbly. Some 120/70 tires have stiffer sidewalls than other 120/70 tires. Bridgestone was know for this in their BT014 so riders had less front end feel from those tires than others. Roadracing World did a street tire test and that was one of their comments on that tire.