Technical Q and A for classic motorcycle maintenance and repair.
Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.
Q: I own two older bikes, a 1976 Triumph Bonneville and a 1984 Kawasaki GPz750. I’m running Metzeler Lasertecs on both fronts and Metzeler Perfect and Metronic on the rears. All four Metzelers say max tire pressure is 42psi. Should I run these new-style tires at owner’s manual suggested settings (28psi front, 32psi rear)? 28-42 seems like a big spread and with the price of tires it could end up being costly experimentation. — Bob Scott/Minneapolis, Minn.
A: This is one of the things I really like about writing this column: It makes me rethink old entrenched ideas. I mistakenly believed that because the bikes remained static while tire technology changed, you should follow the tire manufacturer’s recommendations on the sidewall for inflation. A little research has shown me that is not the case. Every tire manufacturer’s website says follow the motorcycle manufacturer’s recommendations for inflation. A few recommend staying at the top of the recommended inflation range. There are a couple of sites that recommend a change for high-speed, two up, fully-loaded touring. Inflate the front tire to the motorcycle manufacturer’s recommended tire pressure, and the rear to the tire manufacturer’s maximum pressure. The reason given for the front pressure is that is how the braking performance was tested when the bike was made, and will result in the best braking. MC