Sooner or later, you will need to change your tires. Either they will have worn out, rotted out, or been mutilated by some road hazard. When that time comes - and it may come at the side of a road a long way from help - you will need to know how to change your tires. I suppose you could wait for help or push the bike to the nearest dealer, but if you are armed with the knowledge you need and the appropriate tools, you can be back on the road and having fun a lot sooner.

Fixing a flat on a tubeless tire can be as easy as simply inserting a plug and re-inflating the wheel. But, since Moto Guzzi loop frames are blessed with tube tires, a flat always requires removing the wheel from the bike and then removing the tire from the rim.

I've watched car tires being changed at the local tire shop ever since I was a kid. But before I tackled the job myself with my new tires, I sought information. I found that information at a site that Adam Glass put together. Rather than repeat any of the information here, just jump over to his site for a good read.

Tire changing videos

Tire changing video, part 1

Tire changing video, part 2

Tire choices

Updated: 2009 Jun 30

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 in
Rim width (outside dimension): 3 in
Rim diameter: 18 in
Tire size: 4 in × 18 in

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.

Avon:
First choice
- 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.
Bridgestone:
- 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.
Continental:
- Front: Conti Go [100/90-18]
- Rear: Conti Go [110/90-18]
Dunlop:
First choice (Dunlop no longer makes these tires)
- Front: 491 Elite II [100/90-18]; ⁶⁄₃₂ in tread depth when new
- Rear: 491 Elite II [110/90-18]; ⁹⁄₃₂ in 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.
Duro:
- Front: HF261A Excursion [100/90-18]
- Rear: HF261A Excursion [110/90-18]
Kenda:
- Front: K657 Sport Challenger [100/90-18]
- Rear: K657 Sport Challenger [110/90-18]
Metzeler:
- Front: Lasertec [100/90-18]
- Rear: Lasertec [110/90-18]
Michelin:
- Front: Pilot Activ [100/90-18]
- Rear: Pilot Activ [4.00x18]
Pirelli:
- Front: MT66 [100/90-18]
- Rear: MT66 [120/90-18]

Tire mounting lubricant

Updated: 2010 Dec 09

In the past I've used all manner of lubricants from soap to WD-40. I never had any trouble with any of them, though I was always careful to wash off the excess.

Several years ago I bought a gallon of the real stuff and I've been using it ever since. It is inexpensive, lasts a long time, and does a great job.

Balkamp tire mounting lubricant, part number 7652434, sold by NAPA.

Balkamp tire mounting lubricant, part number 7652434.

Photo courtesy of NAPA.

Balkamp tire mounting lubricant, part number 7652434.

Photo courtesy of NAPA.

Direct link to image

Tire size information - Alphabetic / British system

Updated: 2008 Oct 01

The common format for these numbers is ABCCD-EE (e.g., MT90H-18). Explanation:

A: This character is always an “M” and is an abbreviation for “Motorcycle” .
B: This character refers to the width of the tire as a code (see tire width conversions table below). Using the alpha codes, either an “M” , “N” , “P” , “R” , or “S” would work on the 2.15 in wide loop frame rims.
CC: This number refers to the height (aka: profile or aspect ratio) of the tire as a percentage of the width of the tire.
D: This letter refers to the speed rating (see speed ratings table below).
EE: This number refers to the diameter of the rim in inches.

Tire size information - Inch / American system

Updated: 2008 Oct 01

The common format for these numbers is A.AA/BBC-DD (e.g., 4.00/90H-18). Explanation:

A.AA: This number refers to the width of the tire in inches (see tire width conversions table below).
BB: This number refers to the height (aka: profile or aspect ratio) of the tire as a percentage of the width of the tire.
C: This letter refers to the speed rating (see speed ratings table below).
DD: This number refers to the diameter of the rim in inches.

Tire size information - Metric system

Updated: 2008 Oct 01

The common format for these numbers is AAA/BBC-DD (e.g., 110/90H-18). Explanation:

AAA: This number refers to the width of the tire in millimeters (see tire width conversions table below). A quick conversion from inches to millimeters (4 in × 25.4 = 101.6 mm) gives us a value of 101.6 mm. Using metric sizes, either a 100 mm, 110 mm, or 120 mm wide tire would work on the 2.15 in wide loop frame rims.
BB: This number refers to the height (aka: profile or aspect ratio) of the tire as a percentage of the width of the tire.
C: This letter refers to the speed rating (see speed ratings table below).
DD: This number refers to the diameter of the rim in inches.

Tire size to use in a loopframe

Updated: 2009 May 12

Width: Most modern tires are now specified in metric widths. However, the Guzzi documentation specifies 4 in as the appropriate tire width. A little math will tell you that 4 in is equal to 101.6 mm. So, a 100 tire is the closest you can get to the factory specification. It is possible to fit a 110 or a 120 on a loop and still clear the fenders.

Height: Most modern tires specify the height as a percentage of the width. As near as I can tell, back in the day when Guzzi specified a 4 in wide tire, the tire was also 4 in high. That is, the height was 100% of the width. Finding a tire that is the same in both height and width is not easy with many modern tires. Instead, most tires applicable to loop frames will have a height that is 90% of the width.

My first set of tires were 120/90-18 front and rear. I thought they were fine until I put on my second set of tires, 110/90-18 in the rear and a 100/90-18 up front. Wow, what a difference! My skill level in the twisties went way up immediately. The bike turns much more quickly and I love it. No more 120/90-18s for me.

That being said, some very well respected owners like to run the wider 120s.

One reason to run the wider tires is that it fills the fenders more and looks better. If you are really interested in running a 130 or 140 wide tire in the rear, contact Mark Etheridge of Moto Guzzi Classics as he can provide you with the modified components to make the switch easy.
Another reason is to gain a little extra cornering clearance. A 100/90-18 would give a height of 90 mm. A 110/90-18 would give a height of 99 mm. A 120/90-18 would give a height of 108 mm. So, to compare these figures, subtract the height difference between the tire sizes. Using a 100/90-18 as a reference point, a 110/90-18 would be 9 mm taller and a 120/90-18 would be 18 mm taller. These calculations are simplistic and don't take into consideration all factors…but the main point is that the height differences are real.

Tire speed ratings

Updated: 2008 Oct 01

Code	Speed rating
Unrated	95 MPH
S	112 MPH
T	118 MPH
H	130 MPH
V	149 MPH
Z	above 149 MPH

Tires - tubeless conversion

Updated: 2011 Dec 06

DISCLAIMER: DO NOT ATTEMPT THIS MODIFICATION. DESCRIPTION IS PROVIDED HERE FOR ENTERTAINMENT PURPOSES ONLY.

My conversion

Inspired by Greg Field's write-up in the Moto Guzzi National Owners Club (MGNOC) newsletter about his tubeless conversion on his Eldorado, I decided to make the same modification to my Ambassador. Here is what I did:

Used a hand file to dress any gouges in the rim…particularly where the tire bead will seal.
Cleaned the rim with a heavy duty wire wheel on my high horse power bench grinder. This did the lion's share of the work.
Cleaned the rim with a light duty wire wheel on my low horse power bench grinder. This got in a little better around each spoke.
Used a cup-style wire wheel on my dremel tool to clean around each spoke nipple. This finished up the clean up.
Scrubbed down the entire rim with rubbing alcohol.
Let the rim dry.
Applied standard, normal, everyday silicone to each nipple hole…a light first coating. (I used General Electric Silicone II Aluminum & Metal 100% Silicone Sealant; stock number GE5050; P-1285)
Let dry for 24 hours.
Applied the silicone to each nipple hole…a second finish coating.
Let dry for 24 hours.
Applied the silicone to the entire “well” area where the spokes are located.
Let dry for 24 hours.
Temporarily fit two rim strip on top of the silicone. The purpose of the rim strips is to protect the sealed silicone area from accidental contact with the tire or tire irons.
Fit a valve stem from Drag Specialities, part number VS-1218R. The nice thing about this valve stem is that it does not require enlargement of the hole in the rim.
Fit tire.
Remove both protective rim strips. I (and others) have found that the rim strips can migrate and cover the valve stem. When this happens, the rim stip acts as a one-way valve, permitting air in, but not allowing any air to escape. This makes checking tire pressure a fruitless experience.
Inflate and check for leaks.
Ride.

Kim Shick sent me the following tip in a private email. In Kim's own words:

You may find this of some interest regarding “Going Tubeless” . A modified “flexible spaghetti measuring device” was used to easily spread silicone around the rim in one pass whilst using a home-built wheel balancer. There have been no issues with the first wheel done like this and it actually looks professional too (compared to my earlier “double pass” methods). Wish I'd taken pictures of the completed job though…. Seeing as I have another set of rims to do I'll make sure that happens and send you them if you are interested.

Greg Field's conversion

Thanks to Greg Field for posting this information on the Wildgoose Chase forum. In Greg's own words:

For those who want to try it, here's an easier way to make your Borrani wheels tubeless

The key is surface prep. Wire wheel the drop center to get all scmutz and corrosion off of the metal. Then take a conical dremel wire wheel and thoroughly clean each spoke dimple. Blow out all dirt with compressed air. Then clean the drop center and dimples with solvent. Blow thoroughly around the nipples with compressed air.
The key is surface prep. Wire wheel the drop center to get all scmutz and corrosion off of the metal. Then take a conical dremel wire wheel and thoroughly clean each spoke dimple. Blow out all dirt with compressed air. Then clean the drop center and dimples with solvent. Blow thoroughly around the nipples with compressed air.
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First sealing step is to smoosh a little RTV thoroughly into each dimple. Let this cure overnight, and then repeat. This is the heart of the seal, so do it like your life depends on it.
First sealing step is to smoosh a little RTV thoroughly into each dimple. Let this cure overnight, and then repeat. This is the heart of the seal, so do it like your life depends on it.
Direct link to image

Then fit a 16 in scooter tube, and note how much rubber you need to leave in the center to fill to the edges of the drop shoulder. Cut the tube to this width, leaving in the valve stem. Mask off all but the drop center, and then thoroughly clean both sides of the tube with soapy water and then solvent. Get off all the wax and powder, so the RTV will stick well. Then scuff the rubber with sandpaper. When the tube is ready and dry, smear on a light layer of RTV all the way around the drop center. Squeeze out a bunch of extra RTV around the valve stem because this area will be held proud of the drop center by the valve-stem reinforcements in the tube. You want to fill in entirely that area with RTV. Then fit the tube, and use you finger to work out all the bubbles. When this is done the tube will look like a shrink fit into the drop center and will conform even down inside the spoke dimples.
Then fit a 16 in scooter tube, and note how much rubber you need to leave in the center to fill to the edges of the drop shoulder. Cut the tube to this width, leaving in the valve stem. Mask off all but the drop center, and then thoroughly clean both sides of the tube with soapy water and then solvent. Get off all the wax and powder, so the RTV will stick well. Then scuff the rubber with sandpaper. When the tube is ready and dry, smear on a light layer of RTV all the way around the drop center. Squeeze out a bunch of extra RTV around the valve stem because this area will be held proud of the drop center by the valve-stem reinforcements in the tube. You want to fill in entirely that area with RTV. Then fit the tube, and use you finger to work out all the bubbles. When this is done the tube will look like a shrink fit into the drop center and will conform even down inside the spoke dimples.
Direct link to image

Then, fair in RTV around the edges of the tube, and let it cure.
Then, fair in RTV around the edges of the tube, and let it cure.
Direct link to image

Remove the masking and fit a tire. Test for leakage. If no leaks, then you're done. It usually takes less than one 3 oz tube of silicone. If you are using more, it's likely too much.
Remove the masking and fit a tire. Test for leakage. If no leaks, then you're done. It usually takes less than one 3 oz tube of silicone. If you are using more, it's likely too much.
Direct link to image

A better sealant

I extracted this information from Rick (BigRick) off of the Yahoo! Loopframe_Guzzi news group. In Rick's own words:

My concern with my cali was adhesion between the sealant, and the rim, also adhesion between the layers of the sealant with itself. I used 3M Marine Fast Cure 5200 Adhesive Sealant. It sticks to itself real good, even to cured sealant. Its a marine product, and a bit pricey at 20 some dollars a tube, but worth it, in my opinion. I took a piece of scrap bike inner tube, didnt even clean it off, applied a glob of the 5200 to it, and pressed it to a piece of aluminum, I had laying around, never cleaning it at all. The next day, I couldnt pull the two apart, after much trying, I was able to get the adhesive itself to tear, but the bond to the dirty dusty innertube, and aluminum did not come apart! It may be overkill, but this is some tenacious stuff, I dont think tire irons will do much to it, especially if covered by a rim strip, which I embedded into the last layer of the 5200.

3M Marine Adhesive Sealant Fast Cure …

3M Marine Adhesive Sealant Fast Cure 5200

Photo courtesy of 3M.

Pay to have it done

Alternatively, have Wheel Works do it for you. Here is an article describing what they do.

Tire width conversions

Updated: 2008 Oct 01

Permissible Rim Widths (in)	Metric Width (mm)	Standard Width (in)	Standard Low Profile (in)	Alpha Numeric Codes
Examples	###/90-18	#.##/90-18	#.##/90-18	M#90-18
1.60 1.85	70	2.75	-	G
1.60 1.85	80	3.00	3.60	H
1.60 1.85	80	3.00	3.60	H
1.85 2.15	90	3.25	3.60	J
1.85 2.15	90	3.50	4.10	L
2.15 2.50	100	3.75	4.10	M
2.15 2.50 2.75	110	4.00	4.60	N
2.15 2.50 2.75	110	4.25	4.25/85	P
2.15 2.50 2.75	120	4.50	4.25/85	R
2.15 2.50 2.75	120	4.75	5.10	S
2.50 2.75 3.00	130	5.00	5.10	T
2.75 3.00 3.50	140	5.50	-	U
3.00 3.50	150	6.00	-	W
3.00 3.50 4.00	160	-	-	-

Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, 850 California Police Tires

Table of contents

Inner tube use in tubeless tires

Tire changing

Tire changing videos

Tire choices

Tire mounting lubricant

Tire size information - Alphabetic / British system

Tire size information - Inch / American system

Tire size information - Metric system

Tire size to use in a loopframe

Tire speed ratings

Tires - tubeless conversion

My conversion

Greg Field's conversion

A better sealant

Pay to have it done

Tire width conversions