WM. Tires Matter

Posted Oct. 27, 2015

This story is about street and race bike tires, my thoughts and from my admittedly rather dated experience. Today several manufacturers — Bridgestone, Michelin, Avon, Dunlop, Metezler, etc. — offer a wide variety of tires for motorcycles. Metzeler, Dunlop and Bridgestone, for example, have 20 or more different models of tires in their “Sports,” “Touring,” and “American” categories. Some are bias ply and some are radials, some need tubes and some are designed to run tubeless.
Tires

Does it matter? Some folks feel that any street tire from a major company is good enough. Depending on your riding style this can be false. If you ride like an old fogy it may not matter. I have a pal who was rather proud that he was saving tons of money by putting car tires on his Honda PC800. Car tires are, in general, cheaper and last longer that motorcycle tires, but I cringed at the thought of him going around a corner. Apparently he’s managing it as he has not crashed. Yet.

Here’s some things I learned about tires many years ago.

Tires Matter I.

Many years ago, before I started racing, one of my co-workers had a Honda CB350 motorcycle for basic transportation. I wouldn’t call him a motorcyclist per se, but just a guy who rode a motorcycle. One day he came to me with a question.

“My bike kind of wallows in turns and pogos when it’s bumpy. A friend suggested I change the Honda shocks with some S&Ws. I did that and it hasn’t made much difference. Can you help me?”

“Let’s go take a look,” I said. We went out to his motorcycle and I asked him to sit on it. I was intending to look at the shock pre-load, which was the only adjust-ability offered by his shocks. When he sat on the bike I saw that his rear tire was low.

“When was the last time you checked your tire pressure?” I asked. He thought for a moment.

“I don’t remember,” he said. I got out a pressure gauge from my small toolkit and checked his tire. It was about 15 psi, when it should have been in the high 20s.

“Your rear tire is low. Pump it up to the recommended pressure when you get home.” The next day he came to work all smiles. Pumping the tire up to the proper pressure did the trick.

Remember that tires are part of a bike’s suspension — it’s not just the forks and rear shock(s). Keep tires at the recommended pressure and not only will they last longer, but the bike will ride better.
 

Tires Matter II.

(Much of this part is extracted from the book “Racing the Gods.”)
After two years with the Honda CB450 I was ready for a new street bike. When I saw photos of the 1974 Ducati 350 Desmo single I wanted one of those, bad. Logically it was not a good choice, but it was so pretty! The little ochre bike looked to me like a nearly perfect motorcycle. 350 Desmo To my dismay none of the Desmo singles were available in the U.S.

I didn’t really want a Ducati 750 Sport, but I decided to settle for it in place of the 350 Desmo. It was also a beautiful motorcycle, with the same bright yellow-orange bodywork, but I wasn’t sure about the motor’s gangly look. It was a 90-degree V-twin, with one cylinder pointing up and one cylinder pointing forward, making the motor rather long. After I rode it through some bumpy curves and found it handled superbly, I was pleased with the purchase.

A bit later I talked to Phil Schilling about my 350 Desmo race bike, and he gave me the phone number of a Ducati dealer in Canada named Richard White. Phil thought White might have some go-fast parts for my 350cc Desmo racer. I called Mr. White at his shop in Quebec and we talked about oversized valves, high-compression pistons, big-bore kits and so on. At some point in the discussion I told him I had a 750 Sport as a street bike even though my dream bike was the 350 Desmo single, which was not available in the U.S. Then I heard him say these magic words:

“I can sell you one.”

For a moment I was stunned. I recovered quickly and after about 5 seconds I said into the phone, “Tell me more.”

It was expensive but about three weeks later a large crate arrived. In about an hour I had a beautiful little bright ochre motorcycle on my garage floor. I put oil and gas into the bike, acid in the battery and kicked it to life. Now I had two yellow-orange Ducatis, a 750 Sport and a 350 Desmo. Life was good.

4.2

The first ride on the Sportling (as it came to be known) was disappointing. The bike didn’t handle as well as I expected. My 350 Desmo racer was much better. The Sportling didn’t handle badly, there was just a bit of vagueness when cornering I wasn’t expecting.

I took a long look at the differences between the Sportling and the 350 Desmo racer, which handled superbly. They had the same frame and basically the same motor. The suspension was also similar. The tires were different. The Sportling came with old-fashioned tires, a rib pattern on the front and what was called a universal tread pattern on the rear. Even though there was plenty of wear left on the original tires I bought a pair of Dunlop K81s, which were the top choice sporting street tire at the time. I removed the original tires and installed the K81s and took the bike out for a ride.

Ahh. Now that’s the way it should work! All it took was The different tires to give the Sportling the handling I expected. The bike was cutting through the corners with precision, going exactly where I wanted it to go, and with remarkable stability for such a light motorcycle. I rode home with a big grin on my face.
 

Tires matter III

This experience is from racing, but it probably applies to street tires as well. During all of 1976 and 1977 I used Goodyear racing slicks on my Ducati twins, except once. There was a labor dispute at the Goodyear plant and the motorcycle racing slicks were not available. The only other option was Dunlop racing slicks so Dale (my racing sponsor) bought a pair and mounted them on the 883cc Ducati Superbike racer for am AFM race at Sears Point.

I went out for the first practice and began getting up to speed after letting the tires warm up. I didn’t like the Dunlops at all; the bike was sliding around a lot, especially under acceleration. It felt like I wasn’t getting the traction I got with the Goodyears. However, when I got back to the pits Dale showed me the lap times I had turned during the practice. To my surprise the times were just as fast as with the Goodyears. I was puzzled.

Later I was talking to George Miller, a more experienced pro racer, about the differences between the tires. He told me that my experience was just what I should have expected. The Goodyears, he explained, were designed to grip right up to their limit of adhesion, and they would let go quickly if pressed further. I’ve sure experienced that, I thought. On the other hand, he continued, the Dunlops were designed to give a warning as they approached the edge of traction by sliding just enough to let you know they were near their limit. Each approach had its advantage. If you knew exactly where the edge was you could go marginally faster on the Goodyears, the trade-off being that if you went just a bit too far you were suddenly bouncing along on the ground.

The Dunlops gave you enough indication of the approaching limit that you could avoid landing on your head unless you were willing to ignore the warning slips, or were ham-fisted enough to transition from not-yet-sliding to over-the-limit so fast you couldn’t react in time.
 

Tires Matter IV

The previous tales all came from the mid-1970s. This one is a bit more recent, around 1997. When I returned to motorcycling in 1996 I bought a 1988 Honda HawkGT, a blue one, totally stock like this one (image from chicagolandmustang.com). HawkGT blueFrom the HawkGT email list recommendation I got a pair of Metzeler ME3s. Nice tires, rather sporty. I liked them, they provided good grip in the dry and reasonable traction in the wet. They were awful if there was a bit of gravel on the road though.

I wore them out pretty quickly and replaced them with a set of Bridgestone Battlax tires; I forget exactly which model. Again it was based on a recommendation from the HawkGT list. They were good tires, I guess, lots of people liked them, but for me they didn’t offer the same confidence in fast, tight corners that the Metzelers did. Perhaps my riding style pushed the Battlax tires too far? Anyway, I ended up putting the Bridgestones on a second HawkGT I had bought when I sold it (it needed new tires anyway). I put new Metzelers back on my keeper HawkGT and was happy again.

 

So what’s a person to do these days? Buying four or five sets of tires for comparison testing would be prohibitively expensive. There are places to get recommendations, however. Motorcycle magazines will have tire comparison tests from time to time. Most motorcycle models have on-line support groups — email lists or forums — where you can ask for recommendations. I think the best thing is to find people who have your model of motorcycle and ride like you do, and see what they like.

3 thoughts on “WM. Tires Matter

  1. Paul, your description of the Goodyear vs. Dunlop slicks mirrored my experience exactly. I came to like the Dunlop’s as they had greater “feel”. I later tried some Michelin slicks but really didn’t them as much as the Dunlop’s. The Michelin’s did offer greater life, which was important for a poor club racer.

  2. I started racing club events in 1977 on an RD350. Everyone ran Dunlop K81s, because the Michelin PZ2 compound were not club legal street tires. In 1978, the east coast clubs decided to allow the PZ2. My first race of the season was Amateur day at Daytona. I had PZ2s mounted. In a late morning practice, I was loving the PZ2s. I was passing guys on K81s into and out of the corners. I was powering past riders coming out of the right-hand hairpin at the West end of the infield when boom, I was down. The PZ2, like the Goodyear slicks in the story above, had more traction at the limit, but when the limit was exceeded, they stopped holding like you turned off a switch.

  3. Paul Andrews made this comment on the Moto Guzzi Owners group, I’m taking the liberty of re-posting it here.

    ” I just wish manufacturers would keep consistency with their tyres, My Sport ie came shod with Pirelli Dragon Corsa’s in 97. It took a while to get used to them as I was not used to the controlled slide, gently adding power during the slide, would feather the edges of the tyre, (impressing the other riders at the roadside cafe) I got through about 5 sets of these before they stopped making them in my size.

    “I was offered the lower spec pirelli’s which were fitted, on the way home about 55miles I was disappointed, and noticed at home they were lower profile than recommended and too close to the shaft spring retainer for comfort. (in the event of a puncture would have interfered with the shaft! ) I mentioned this and the dealer suggested I try the Avon’s hi-spec tyre.

    “I agreed (though reluctantly as previous bikes had been crashed trying to ride sideways on both wheels! ) Again the handling was affected, though not as badly as previous experience. many other riders were singing praises of the Battleaxe, so I thought this would be my next tyre… although good in most areas, they were not a patch on the original fitment, so I stuck it out for 3-4 sets. But was avoiding riding this bike in wet weather, due to a very nasty Roundabout, that would feel very greasy in damp weather, causing the bike to slide uncontrollably even at super slow speeds.

    “But there came a point when I could no longer ride my commuter bike (a Cagiva Canyon 600), due to health reasons. I bought a second Sport ie originally for spares, (sidestand problems) which was fitted with Dunlop Sportmax. these felt comfortable, so tried a new set, the new set had a different tread pattern to the old ones fitted previously, but found them to be a very good all round tyre, especially in the dreaded English rainy season (most of the year..lol ) in fact so good I bought another set for my other Sport ie.. a renewed confidence in the handling was born from this, to the point of hardly slowing for the wet stuff, even on the aforementioned greasy roundabout! my next and most recent purchase of the dunlop found another tread change and a mixed compound to give longer life.. Grip is still good but these seem very twitchy on today’s uneven road surfaces, .. Next year… well I’ll most likely go for the dunlop again, BUT, I think a letter to dunlop is on the cards.”

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