Tire sizes for a Seca Turbo

I know the proper sizes, but am not completely clear on a crossover size.

I need a 3.25 V19 front, and a 120/90 18 rear.

However, I want Pirelli Sport Demons, I always liked them on my K75, and need to replace the dryrotted tires on my new Turbo.

So, I found that I am now wearing Dunlop GT 501 Arrowhawk in sizes 130 80 18 rear and 100 90 19 front.

The rear is an 80 instead of a 90, and a 130 instead of a 120. The tire is very far, and doesn't look like it fits the rim right.

The front looks good.

I can get a Pirelli Sport Demon 100/90V-19 Front , and Pirelli Sport Demon 120/90V-18 Rear.

Looks like they will work fine, but is there an advantage to the 130/80v 18 for the rear?

Do I need to replace the metal valve stems?

Thanks,

Jim

 

Your sizing is correct sir.

Consensus seems to be to stick with the OEM size.

No, but they're inexpensive so why not just do them while your're in there? The stems themselves won't go bad but the rubber seals where they pass through the rim are likely 25 years old and getting brittle. BTW, I wish I'd put an angled one on my rear - awful hard to get some chucks on the straight one because not much clearance to the brake drum.

 

Thanks, I ordered Pirelli Diablos for it in stock sizes!

I am also ordering new metal angled valve stems!

Jim

 

Do you need some wheel weights? I've got a couple hundred adhesive 1/4 oz. ones laying around.

 

Thanks, I appreciate it, but I am the local tire changer of my club, so I have a decent machine, and plenty of weights.

Jim