Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models
Good rubber is a necessity. I once read that the combined contact patch for the both the front and rear tires is the size of the palm of your hand (David L. Hough - Proficient Motorcycling). That being said, just about any tire you purchase today will be better than the tires available 30 years ago.
I think it is a usually a very good idea to purchase tires as close to the manufactures original specifications as possible. Modifying tire sizes can have a dramatic effect on the handling of the motorcycle. That's not to say you can't make modifications, just that the consequences may or may not be desirable. Here are the Moto Guzzi specifications for all V7, Ambassador, and Eldorado models:
- Rim width (inside dimension): 2.15 inch
- Rim width (outside dimension): 3 inch
- Rim diameter: 18 inch
- Tire size: 4 inch × 18 inch
Here would be my choices. In making these selections, I chose touring or cruising tires because that's what I do with my Ambassador and I like to get as many miles out of my tires as is safely permissible. If you choose sport rated tires, you can expect greatly decreased tire life (but all that gooey traction will let you ride the bike up a wall).
When viewing these selections, keep in mind that I tried to find the tires I think would be best for the style of riding I do with my Ambassador. I chose to include some brands below for which the tires they currently offer don't really meet my needs. I included these selections so that individuals who choose to be loyal to a particular brand would see it listed here. In the end, the tires you choose to put on your motorcycle are your own business.
- Front: Roadrider [100/90-18]
- Rear: Roadrider [110/90-18]
Second choice (Avon no longer makes these tires)
- Front: AM20 SuperVenom [100/90-18] (No longer available)
- Rear: AM21 Roadrunner [110/90-18] (No longer available)
- Note: This was my first set of tires on my Ambassador, only in the wider 120 width on both the front and rear. I was pleased with the traction, but I personally felt the handling suffered due solely to the width. I switched to the Dunlops because I wanted to get a longer wearing tire. The rear tire lasted about 8,000 miles. Not bad, but I'm seeing if I can get one to last longer.
- Front: S11 Spitfire Touring [100/90-18]
- Rear: S11 Spitfire Touring [110/90-18]
- Note: I am currently running these tires.
- Cheng Shin:
- Front: Marquis Sport/Touring [100/90-18]
- Rear: Marquis Sport/Touring [110/90-18]
- Note: For a short time I used these on the yellow Eldorado Project Bike (until I sold the bike), they worked fine but I don't recall any specifics.
- Front: Conti Go [100/90-18]
- Rear: Conti Go [110/90-18]
First choice (Dunlop no longer makes these tires)
- Front: 491 Elite II [100/90-18]; 6⁄32 inch tread depth when new
- Rear: 491 Elite II [110/90-18]; 9⁄32 inch tread depth when new
- Note: I got 16,522 miles out of the first rear tire and 14,398 miles out of the second rear tire. I got 21,672 out of the front tire.
Second choice (This front tire has a tendency to track pavement grooves)
- Front: D404 [100/90-18]
- Rear: D404 [110/90-18]
- Note: I've never used these on the rear. I got 9,248 out of the front tire.
- Front: HF261A Excursion [100/90-18]
- Rear: HF261A Excursion [110/90-18]
- Front: K657 Sport Challenger [100/90-18]
- Rear: K657 Sport Challenger [110/90-18]
- Front: Lasertec [100/90-18]
- Rear: Lasertec [110/90-18]
- Front: Pilot Activ [100/90-18]
- Rear: Pilot Activ [4.00x18]
- Front: MT66 [100/90-18]
- Rear: MT66 [120/90-18]
- Front: 230 Tour Master [100/90-18]
- Rear: 230 Tour Master [120/90-18]