One of our readers, Óscar, tells us in our contact form that he is restoring a classic, a Kawasaki GPZ900R that had been sitting in a garage for years. After changing all the fluids, gaskets and hoses that may be cracked due to the passage of time, it is time to choose which tires to put on the legendary Top Gun, and that is where the doubts have assailed you.
The truth is that riding a vintage motorcycle is like traveling back in time, but even the most venerable machines need an occasional update to keep up with modern demands. As long as you give it some pampering, it will surely give you endless satisfaction, and a lot of it will depend on whether you get the tires right.
Óscar says he is in doubt whether to fit tires from an older model that is still manufactured, or choose one of the latest generation, but he believes that in this case he may not be able to get all the performance out of them and therefore, they may not perform. correctly.
Classic motorcycle and modern tire
We recommend that you choose a modern tire, because if there have been advances in recent years, these have been above all at the level of suspensions and tires (in addition to electronics), and these two sections can be tweaked and updated on your mount, thus that the improvement will be enormous.
As an example, readers tested the Bridgestone Battlax T32, a Sport-Touring tire that suited a classic like the Suzuki Bandit 400 like a glove. Without a doubt, they will do just as well on the GPZ900R.
As for measurements, the GPZ mounts 120/70ZR17 at the front, so you won’t have any problems. At the rear the original measurement is 150/70ZR18, but you can mount a 160/60ZR18 that falls within the legal limits (-2.7%). Of course, you will have to check that the rim’s throat measurement allows this without the casing being deformed.
As for the pressures, you should use the original ones, although you may need to slightly touch up the rear when installing a wider rubber. Of course, it is essential when installing modern tires on a classic motorcycle, which offer much superior grip, to perform complete maintenance on both the fork and the rear shock absorber.