Unhappy with the 10 year old technology stock Magna/ Sabre tires? Looking for an alternative? Read on, the answers lie within.
It must be stated that Dunlop, at their web site, has a standard disclaimer about fitting radials to bikes that didn't come stock with radials. I think this is needed to cover their butts in case of a ridiculous lawsuit which could & probably would develop.
For those of you who just want the summary, the best tires for the Magna or Sabre are as follows:

1st Choice:   Dunlop D205's
2nd Choice:  Any radial except Avons.  Read for furthers details on this.
3rd Choice:  Metzler ME99A/Me33 Combination
4th Choice:  (Economy with good characteristics)  Bridgestone SE11's

Contents:

Introduction History: My first Experience with Radials  The Blowout Story (Skip if you hate Motorcycle road stories)  A Tire Size Alternative  The Radial Difference & Dunlop K591's  Further Experiences With the K591  Update: The Return to Avon Radials

What the numbers in the Tire Sizes Really Mean  Tire Size & Height Difference  Conclusion & Tire Chart  Sabre Radials (V65)  Sabre Radials (V45)  Interceptor Radials

Introduction
One word says it all: Radials. To my knowledge, I was the first person ever to mount radial tires on the Magna. This occurred in 1993. Since then, I have had a lot of Radial 'converts,' including Sabres, V45 Magnas and Interceptors. Nothing but rave reviews. These will be summarized at the end of this section.
I have tried almost every brand of tire on my two V65 Magna's, a total of 120,000 miles, and I will give my impression of each tire. I will talk about wear on the back tire only, since each front tire lasts about twice as long as the back. First of all, there are the "Stock" tires, Dunlop K627 & F11. The back lasted about 9000 mi., and the handling was poor. I switched to Bridgestone dual tread compound, giving into their claim of "hard in the middle, soft on the sides". The Bridgestone wore out in the middle like every other tire. When I called Bridgestone to inquire why the tire wore this way, they said that the difference in "hardness" of the compound between the sides and the middle was about 3%. This is not a big number, and other manufacturers claim that they can't hold a whole tire to within 3%, much less specific areas. I did get about 11,000mi, which is about 3000 more than the stock, and the handling was better than stock. Next I tried the combination of Metzler ME99/ME33. This combination handled better than the Bridgestone and the stock tire. The back tire lasted about 8500mi, which is about the same as stock. I tried a Continental on the back, which bubbled up on me at the end. I learned to be careful of the weight ratings as well as the load ratings - both count as I found out.

History: My first Experience with Radials
I saw the advertising for radial tires, and I figured I would give them a try. The only manufacturer who made the rear tire in a 140/16 size was Avon. I tried their combination of ST22/ST23, 140-80/ZR16 Rear and 110-80/ZR18 for the front. The handling was phenomenal. I felt like I was riding a race bike. Not only did the handling improve, but the gas mileage and the ride comfort improved noticeably, just as they claimed. I thought that I had found the perfect tire! I can't even begin to describe the difference in ride that I felt. There was a dark lining to this silver cloud though. On one cross country trip, the tire bubbled up and blew out, just like a previous Continental tire. This happened a long way from home, Sonoma Calif. to be precise. Avon was very cooperative, and went out of their way to obtain the blown tire from a shop in California where I had left it, and to evaluate it. They sent me a new tire, the same one, since at this time I thought it was a defective tire, and I had been quite loaded down with equipment and a passenger at the time. I put the new tire on in Vegas, dropped off a lot of my load and my passenger (She flew back, as planned previously) and continued on my cross country adventure. When I got to Kentucky a few weeks and 3500 miles later, I had noticed that the tire began to bubble again. This time there was no overload, since I was riding One-up with a lighter load. Avon came back and said that the bike was "too much" for the tire, which had a "B" rating, even though the weight of the bike was well within limits. It was too bad, since I fell in love with the radial design. Being stuck for a tire on the road, I had to mount a Cheng-Shin on the rear for the ride home. I was not happy with it. I took it off after about 2000mi, and its still in my basement.

When I called Avon, they retrieved the actual tire from the Honda dealer. I bet Joe Bird is still wondering where how the tire got in his trash (see below). After retrieving the tire, they sent it for analysis, and the result was that the 140/80 rear tire was overloaded. I would have tried the 150/80 right then, but I wasn't sure it would fit at that time (young and foolish). All this effort on the part of Avon due to just one 800 phone call from me. I guess they are serious about their tires.
Avon said that they want to see any malfunction, and even small shreds of a tire will tell what happened.
If a tire was not "sent" back for evaluation (They are also guaranteed) then I would take little notice of one persons' experience, however serious it might be. It is so easy to just call an 800 number, Avon said that they would have went quite far to get one of their bad tires. I think if you gave them the spot on the road where you left it, they would probably have had it retrieved.

The Blowout Story (Skip if you hate Motorcycle road stories)
When my tire blew, I was on the road in California. The tire was completely wasted, sidewall gone, no chance of repair. It was in Sonoma, on the way to Yosemite, on a Saturday Afternoon. There was one MC shop within 120 mile radius, in Sonoma, which wasn't going to be open till Tuesday. A nice old man drove me around (with my back rim in the back of his pickup) for quite a while looking for shops. I even called the owner of "Joe Birds Honda" in Sonoma to see if he would open up his shop and come in just for a few minutes and sell me a tire. He wouldn't do it. So what I did was to hop Joe Birds Honda's fence, and fish in his trash for any tire that would fit and maybe hold air. This course of action was actually suggested to me by two local policeman who seemed concerned (unbelievable!), and were quite amused in watching me hop the fence and fish through Joe Bird's trash. I found two tire candidates, one with a nail in it, and went to a regular car gas station, patched the nailed tire, and mounted it on a rim. It worked well until I reached Las Vegas, where I had a new tire mounted. I left the old tire in the trash at Joe Bird's Honda.

A Tire Size Alternative
It was late 1993 when the Avon radial blew out, and I thought I was SOL when it came to mounting another radial tire. No other tire company makes a radial in a 140-XX/16 size, but I did notice that the Kawasaki Concourse takes a 150-80/ZR16 rear and a 110-80/ZR18 front. I wanted radials so I got information on the sizes from Dunlop on their Sportmax. At the time, they were the only ones who had any 16" size rear tire besides Avon. I found that the limiting factor in tire width was the clearance between the rear caliper brace and the tire sidewall. After very careful measurements, using the Dunlop sizes as a guideline, I found that the clearance was so tight that the measurement error exceeded the measured numbers. In other words, the fit was so tight, that it was impossible to get a proper measurement without actually mounting a tire and seeing it mounted for myself. This presented a problem, since I did not want to shell out over $100 for a tire just to see if it fit. What I did was took an old worn tire from my friends Concourse, and mounted that on a rim to test the fit. It was a little close, but there was enough clearance. I was very happy, since now I could have a set of radials that fit! I rode around with the Sportmax (Three sets of rear and two fronts) for a year or so, they lasted about 9000 miles each (rear), and the handling, ride and gas mileage was great! Unfortunately, Dunlop in their infinite wisdom, stopped producing the Sportmax in that size last year, so I was SOL. I hurried and bought a few to hold me over, knowing that they would soon run out. Last year, also, Metzler (MEZ2) , Michelin (A89X) & Pirelli (Dragon) also started making radials in that size, but I couldn't get my hands on any. It seemed that there was a worldwide shortage.

The Radial Difference & Dunlop K591's

To illustrate the difference that radial tires made, I will relate another experience I had on the way down to Florida. I had the Dunlop Sportmax 150-80/ZR16 Rear and 110-80/ZR18 Front mounted, and went down the Blue Ridge Parkway, and then to Deals Gap. The Bike handled great, but I noticed that it wasn't up to par. Around the Georgia area (about 2000 miles on the tires), I noticed that the front end started wobbling. I have sort of a front end phobia, since the last Magna I had I wiped out on the highway because of the front end, but that's a different story. When I got down to Florida (about 3000 miles on rear tire) the handling and wobbling was so bad I decided to bring it to a shop. I had noticed that the rear tire had scalloped a little, but since the wobble seemed to be in the front end, and I still had front end phobia, I neglected that observation. As it turned out, the rear tire was mounted backwards! Needless to say I was furious at the dealer in New Hampshire that mounted the tire. Anyway, I had a set of Dunlop K591's installed. The bike rode fine, no wobble!
The handling was noticeably worse than with the radials (even when the radial was mounted backwards, at the beginning anyway) and the gas mileage took an immediate plunge. I was averaging about 150 to 155 miles on the highway (normal driving, two up with gear) with the radials, before the gas light went on. With the K591's the gas light came on at 135 to 140 miles! I thought it was bad gas, etc... but finally after a few tankfulls of consistent mileage, it was obvious that the K591's were the culprit. The ride was a lot rougher with the K591's also. I would not recommend the K591's as tires for any bike. The drop in gas mileage calculation includes the errors introduced from fitting a smaller profile (110-80 as opposed to 110-90) tire on the front. More of this to come later.

Further Experiences With the K591
I thought the poor quality/handling of the K591's was unique to the Magna. I was wrong. I took the Penguin school race course in May '97, and used one of their EX-500's. It was a rainy day, and the bike handled poorly, I could feel the tires slipping out even on slow turns. When I went to the instructors about this, they said that they were not surprised. They informed me that the Dunlop K591's were extremely poor in the rain, and that the Metzlers were far superior in this respect. I asked them if they had any Metzlers hanging around that they could mount, but they just pointed to the "Dunlop" stickers on the bike. Dunlop is one of their sponsors. Their consolation was stating that the K591's were better than the Metzlers when dry. I doubt it. There were two other people who rented the school's EX-500's. When we were talking, I noticed that one of the other EX's had Metzlers! When this guy buzzed by me on the track, I thought that I was just doing really poor. As it turns out, he felt no slipping in the turns! The other guy who had the EX with the K591's wiped out once or twice.

A person commented on the MagSab list saying that the Dunlop K591 tire was great. Usually, I would let this 'personal opinion' on tire brands slide, because everyone has a right to express his/her own opinion. However, in the Dunlop Vs. Metzler debate, there is no comparison. I have tried both on the Magna, at around the same time period. On the Magna, the Dunlop K591/F/R is inferior to the Metzler ME33/99A in every respect, Mileage, Handling, smoothness, etc. This is not an opinion. This is an observed fact (observed by myself, I'm afraid) on the Magna. I have written records of both, and will be glad to share them on request.

In my opinion, however, due to the different ride/feel/mileage of the two tires, I think that it would be directly applicable to the Sabre. Therefore, until someone tries the Metzler right after the K591's on the Sabre, or visa-versa, I'm afraid I'll have to extend my observed quality difference to the Sabre. I don't think it's too big of a step.
Dunlop does have better advertising, however.

Avon Vs. Metzler is another story. They are a lot closer in quality.

Update: The Return to Avon Radials
As mentioned above, I put Dunlop K591's on the bike, and I was not happy with them. I got less than 7000 miles on the back, and the handling was poor compared to Metzler ME33/ME99a, Much less radials. I have tried for a total of 3 years to get a hold of Metzler MEZ2 radial tires, with no luck. I keep getting the line "two weeks" which never comes. I finally decided to take a chance again with the Avon radials. The last time I used them, I had the problem with the 140-80, and I wasn't aware that I could have used the 150-80. I talked to "Max" at Avon, and he assured me that the 150/80 was adequate for the Concourse, which is a heavy bike, so I figured that it would have no problems on the Magna. It is rated for 750 lbs. load, so I figured I'd be brave and cautious. I'm glad I did it. The Avons gave me the fantastic ride that I remember, and after 5000 miles, they are wearing well. They also survived the cross Labrador Highway (the road from hell) so to me, they have redeemed themselves, even though the 150-80 has a B rating. I am peeved that Metzler cannot solve its distribution difficulties, and will not in the near future purchase their tires. As for now, my choice for the Magna is:

Front: Avon AV27, 110/80 ZR18
Rear: Avon ST23, 150/80 ZR16

What the numbers in the Tire Sizes Really Mean
Example Size 110/90 18

The first number is the width, approximately, in mm. This is not exact, and is an actual range of values that approximately falls within a window.

The second number is the aspect ratio, or the ratio of the height of the tire to the width.

So, a tire sized 100/90 would be narrower than a 120/90, (by approximately 20mm, a lot) and since the aspect ratio is the same, the actual diameter will be smaller, but not by much, I don't think you will even notice it.

Front tires and rear tires are completely different, and perform completely different functions. They should never be interchanged.

Dunlop, as well as all the other tire manufacturers, publish the sizes (actually measured, in inches and mm) in their catalog. This was a good place to start for me. The catalogs are free, and they all have 800 numbers. If you want the numbers, let me know, I will look them up. Eventually, I will post the catalog numbers within this web site.

IMO, for what its worth, given the rim width of the Magna, I wouldn't try to fit a narrower tire on the rim. The change in ride height is not worth it. Also, in trying to "widen" the 100/90 to fit the rim, you will ruin the profile. The same is happening with the 120, it is being "squeezed" on to a smaller rim. Usually, though, going up or down one width-size is not too bad, and the 120 on the Magna is adequate, at best. Radials are more forgiving in this respect.

Tire Size & Height Difference
If you are counting on tire sizes to make a significant height difference, I think you will be disappointed. I've had the a V65 since 1991, and have failed to find a tire combination that will make a noticeable difference in ride height. That's one of the reasons I modified the suspension.

If you want a "shorter" tire than stock, for example, most manufactures make a 110/80-18 front, the width is the same as stock, it takes the same size rim, and the profile is lower, thus lower ride height. I currently use this size now, and the ride height is not noticeably different than the 110/90.

I won't repeat my tire experiences, since you already read them, but I will say that Avon, Metzler, Bridgestone, Dunlop, and the others (in that order) make Magna size tires in the following series:

Avon Radial AV27 F/ST23 R
Dunlop D205 Radial
Michelin A90X Radial (I have not tried these, Yet)
Metzler Bias Ply ME99a-R/ME33-F
Bridgestone Bias Ply Dual Tread Compound SE11 F&R Dunlop Bias Ply K591 F&R

Not Recommended by myself
Cheng-Shin (rough Ride, Poor Handling)
Continental (rough ride, bubbling)

Conclusion & Tire Chart
The biggest improvement in ride, handling, and gas mileage I've found (besides synthetic oil) for the V65 Magna is radial tires. I have had both a 1984 and a 1986. I use, and will continue to use radial tires, 150-80/ZR16 for the rear, and 110-80/ZR18 for the front.  I have since modified the suspension to improve ride/ handling with good results, but that will be a future communication.

Also, watch the load ratings, and under no circumstances will I Use a "B" rated tire, (amended above) even though the load rating seems to be OK.

Tire Pressure

I find that the radials don't feel right unless inflated to their maximum rated pressure, within two psi. This is verified by information I have obtained from the manufacturer. Bias ply is another story, and usually doesn't require the maximum pressure for maximum performance.

The following chart chronicles most of the tires I have used to date on the V65 Magna.

More About Radials, & Radials on the Sabre
The rumor that radials cannot be used on older bikes stemmed from the fact that most of the radials made were made for really wide rims. The Magna & Sabre have relatively narrow rims, and it is hard to find a tire size to fit. But, due to the "flexible sidewall" of the radial, the manufacturer actually gives a range of rim widths for each tire.

The Magna has a 3.00 inch back rim and this width fit right in the middle of the rim width range. For the 150/80 the Magna rim is at the low end of the range, but still fits perfectly, and, as I have stated before, after using these, I will not go back to bias ply.

Another thing to consider is the front tire. A radial should not be fitted on the rear without one on front. Additionally for the front, if an "80" profile is used on the rear, a matching "80" profile should be used. This will keep the geometry the same, just lowered by about .15 to .3".
This seems like a lot of trouble, but IMO, I can assure you, all the work I did in fitting radials on the Magna was well worth it. It seems that the Sabre has even more to gain, with is single shock rear.

Sabre Radials (V65)
By Barry Tudor

Note From Tony D: This is an excerpt from Barry, who to my knowledge, is the first person to mount radial tires on the Sabre.

Barry Writes:

Having had several big bore V-4 Hondas in the past, I was anxious to purchase this latest in a good group of bikes. I had previously owned a 1984 VF1000F Interceptor, which slowly and painfully died the slow death of inadequate oil supply at the cams. I subsequently owned for a very short time a 1985 V-65 Sabre with many miles on it, suffering from the same problem. After a single season, I sold it, lamenting the beast's weak point. At least I didn't lose any money on that one.
Recently I purchased a pristine 1984 V-65 Sabre with only 7600 miles on it. The oil mod was the necessary first change. (I HAD learned something after all!)

One of the other modifications necessary in my humble opinion was the tire upgrade. Well knowing and understanding the narrower rim widths on our beasts, I set out asking questions about radial replacements. This was obviously uncharted water. Having read various experiences from radial fitment to a wide variety of bikes, I became convinced that as long as the width of the tire did not exceed the recommended rim width by tire manufacturer (data hard to come by) everything would be just fine.
The manufacturers data is not that hard to come by. In the future, this page will post some of the sizes.
Still cautious, and curious as ever, I read several FAQ's on different bikes which had changed over to radials. Almost all of them had rims a little wider than those my beautiful beast had. I was almost at the point of buying Metzler Bias Ply tires, which I had good past experience with.
Then I came across a posting from you (Tony D, thats me) which pointed out your radial fittment of the Magna. Being generally familiar with that particular ride, I was intrigued. I closely scrutinized
I opted for the Metzler MEZ-2, sized 140/80ZR17 for the rear , and 110/80ZR18 for the front tires (all manufacturers). The stockers were the same size on front, and only one size smaller in the rear (130 vs. 140). Tough luck, I couldn't find a pair of the Metzlers. Only the front tire was available, and a two week backorder for the rear. I lamented, and opted for the new Dunlop D205 sport touring radials. Unfortunately, the same result, not in stock, would have to wait. My last choice was a tire I had no experience with, the Avon AV27/ST23 front/rear pair of radials. These were all sport touring radials, designed supposedly, to allow longer tread life while maintaining great traction. For the prices of these tires, I expected a lot from them. The Avons were spooned on and balanced.

Well, after just over 1000 miles of happy destiny, I am reporting to you my opinion of the fitment of radial tires to the V-65 Sabre "Razorbeast": DO IT! DO IT, DO IT, DO IT!

I was amazed from the beginning at the control and stability the new tires gave this Beast. Being a rather robust individual myself, I took it easy on the tires for about a hundred miles, making sure they were properly scuffed in. I marveled at the ride quality. It was almost as if I had ridden a different bike home. She was acting more like the old Interceptor than the Beast she is. (The Interceptor DID handle well).
I checked for excessive wear (OK, what IS excessive?) the other day, making sure that these tires would last. I can detect no appreciable wear. They seem to be at least as wear resistant as the Metzeller ME55A Metronic bias ply tires I had on the old interceptor, and that was pretty good!
Now understand, I weigh a little over 200 pounds, ride a big, heavy bike, and like the way the throttle snaps my head back when I whack it a good one. Hell, who don't?! So I end up whacking it open often, and fully partake in the adrenaline rush it offers!
So I will post again, to give regular updates on the wearing of the tires.

Sabre Radials (V45)
By Steve Stokes stevieb@rbdc.rbdc.com

I purchased my radials at a local stealer, (not my dealer, they didn't have any), while I had a case of "gotta haveum now!!". Well, "gotta haveum now" costs much more than Richard paid. So if you can order like Richard did; it's cheaper.

As for my impressions...... "HOLY SH!TE, BATMAN !!!"

You will be amazed at the ride and feel of these rubbers. As Mike S. said "I usually qualify any advise I give, But gettum now." Like Richard said, Pay attention when you first ride because you'll think " turn" and the damn bike will turn out from under you before you're ready. You'll find yourself in a catch-up mode faster than you can say Doh!

The bike sits slightly lower, I didn't measure, but its a little lower. However , At the Gap I never scraped a peg. If you accelerate through the curves the bike is on rails. At a steady pace or if slowing down I find that I need to place slight pressure on the outside bar to keep the bike from falling into the curve. Another plus is when I run over gravel in a turn, ( this is a few pieces not a lot), the bike stays steady and dosen't move lateraly as it does with the 491s or 591s. This usually leaves wrinkles in the seat when I get off. No more!!! because now I am radical(TM, Richard W). I haven't checked the milage yet,( was real good on the trailer), but that's next.

For the record: bike 83 V45S 51K Black ( see gallery)

Tires: Dunlop Sportmax Touring D205's

Front 110/80/ZR 18
Rear 140/90/ZR17

You'll have to install the rear then pump it up to get it in but there is plenty of clearance once mounted. The ride feels super.
 
Radials on the Interceptor
By Mark Cataldo

The quick turn-in characteristics of radial equipped SabMags is well documented on the list. Well friends, if you think your Sabre or Magna with radials turns "Right Now!", try the same thing on a radial equipped Interceptor with a 16" front wheel!! I anticipated this and went in fairly well prepared, but there IS a learning curve (pun ignored). There’s nothing here that would scare a seasoned ‘Ceptor rider, but be prepared to make adjustments in technique and DO take time to research. The Mac 90’s have been stable and predictable to the points that I’ve pushed them (with both now inflated to max recommended pressures). I give high marks to the front, as it’s done everything I’ve asked of it. As for the rear, there’s no denying it’s a lot of tire for the bike and I wish I had the wider rim. But, it’s not overpowering and works very well when pumped up. I hope to gather more authoritative information on mileage and longevity, but for first impressions they’re definitely a go for me and seem to be a good value for the money.