PRII Rear Tire

[Big-D]

NOTE: I had first posted this reply in the Group Buy category, but after rereading the rules posted there, I thought perhaps this reply to be more appropriate out of that subject line.

Many riders don't believe the difference between the "C" and "D" rear tire on an FJR is significant, but there is a reason that tire is type specific recommended for the FJR. However, having had a fairly intense discussion during the SW-FOG and during the SW Colorado ride taken at the end of August, concerning what happens during a rear tire blow-out. Honestly, never having had experienced a blow-out of a rear tire on a high speed street bike, I figured it would just wiggle a bit while you slowed down. But listening to stories from some riders of both BMW's and FJR's, a rear tire blow-out can easily send you high-siding down the asphalt. And that is while riding in a straight line. Blowing a rear tire during a turn could prove to be even more disastrous.

So although tire choices are just that, choices, personally, I think I'll continue paying the extra $20 bucks or so for that extra belt and stiffer side wall. Because it's that side wall that could save your ass in a blow-out. Until someone makes a tire better, I really like the feel of the PRII's over the Z6 that my FJR came stock with. As a new member of the Los Robustos, I consider myself riding 2-up even while riding alone.

 

[FJR Flyer]

I thought the "B" rear tire was for the FJR?

 

[Knifemaker]

Yes, which is which? C stiffer or D? What about the B?

Because

I know my wife would like the stiffer one.............................

again

I want to make sure I get the stiffer one for my wife...........

last one

I'd feel better getting the stiffer one under my wife............................

KM

 

[Big-D]

OK, I screwed up my lettering. You're right, the FJR requires (suggests) "B" rated, not the "C".

Wow, I had better take a refresher course of my ABC's!! No wonder every distributor keeps telling me the D's are not in stock.... damn

 

[Zorlac]

I just can't get past the fact that they both are weight rated at 805 lbs.

On my old Concours, the riders debate the flexibility of bias ply tires vs radials, saying that the radial flexing keeps contact patch on the road better, then the manufacturers want stiffer radials too?

The standard PR2 is wearing like iron for me so far, very impressive actually.

 

[Knifemaker]

Blowing a rear tire during a turn could prove to be even more disastrous.

I would of course agree, but what are the odds of that? I do not think in all my years of riding I have, or anyone that I know or read about has had a "blow out"...

Yes, there have been cases of hitting a nail and leaking air fairly quickly, but an actual "blow out" where the tire loses air instantly....how often does this really occour?

KM

 

[Happy Rider]

Last year I was following a friend on I-40 in the fast lane at about 80mph. He was riding a HD Dyna with laced wheels. His rear tire blew out and the ass end of the bike shook a bit. He stayed off the brakes and got it to the right shoulder without much trouble. The same guy on the same bike had a second rear blowout on I-5 leaving LA about a month ago. Same results. His bike use to have laced wheels. He has now swiched to cast wheels hoping that getting rid of the tube will help. I guess he is just unlucky.

 

[Big-D]

The difference between a radial and biased ply is Radials are constructed of three separate pieces fused together. Biased ply is one piece that is bent into a U shape to form the shape of the tire. Biased ply tires flex (roll-in) in the side walls during turns and the contact patch lifts, a radial remains a constant contact patch whether turning or going straight.

One interesting conversation I had with Beemerdon and Chuck Doucet (both members of the AZBeemers) group, where Chuck was describing how he was riding down the freeway, I believe he said North bound on I-10 out of El Paso, TX riding his BMW with his wife on board lost a valve stem and immediately lost air in his rear tire. He described his situation as the rear end of his bike slide sideways (because the tire buckled up to where only the aluminum rim was in contact with the road) where he actually saw the ass-end swing around in front of the bike, then suddenly rubber touched the pavement, causing an instant High-Side throwing him and his wife down the freeway at 65-70mph. Needles to saw, they were not feeling so good at that moment. That was one of several stories heard during that conversation that were caused by sudden and complete air loss in a rear tire. I would guess Chuck has 40+ years of riding experience.

Like you, I have never lost a rear tire at any speed, so I cannot speed with personal experience. On a regular basis people on this forum mention atgatt, so why worry about $20 when it comes to your tires.

This almost looks like a commercial announcement for Michelin.

 

[cpsfjr]

Had a rear blowout before. Front tire ran over a pocketknife blade, flipping it into the rear tire. Sliced a hole about 2/3 of an inch long. At 65 mph the tire flattened to about 10 psi in ~ 5 seconds. Serious fishtailing as the tire rocked from one side to the other while quickly deflating...a real rodeo (with pillion aboard, too), but managed to keep it up, stayed off brakes, and made it to the side of the road.

I think M/C blowouts--especially with radial tires--are rare, but they can happen. Most important thing is your initial reaction, staying as calm as you can, and being very careful about using brakes, if at all.

 

[Zorlac]

"The difference between a radial and biased ply is Radials are constructed of three separate pieces fused together. Biased ply is one piece that is bent into a U shape to form the shape of the tire. Biased ply tires flex (roll-in) in the side walls during turns and the contact patch lifts, a radial remains a constant contact patch whether turning or going straight."

So if they stiffen up the two sidewall pieces, doesn't it become more like the bias ply?

"riding his BMW with his wife on board lost a valve stem and immediately lost air in his rear tire."

A B,C,D... version won't make much difference here, better go with metal valve stems too.

 

[GPRIDER]

Last year I was following a friend on I-40 in the fast lane at about 80mph. He was riding a HD Dyna with laced wheels. His rear tire blew out and the ass end of the bike shook a bit. He stayed off the brakes and got it to the right shoulder without much trouble. The same guy on the same bike had a second rear blowout on I-5 leaving LA about a month ago. Same results. His bike use to have laced wheels. He has now swiched to cast wheels hoping that getting rid of the tube will help. I guess he is just unlucky.

I had a similar experience on my old XS11 almost 30 years ago. Don't know if I would consider it a blowout,but the tire lost pressure quickly. I had the same experience as Happy riders friend. The bike shook and the rear weaved a little bit, but got it over the shoulder with no problems. Had my girl friend on the back too. It's the only time in 30+ years of riding that it has happened.

GP