Guest Pete McCrary Posted August 17, 2007 Share Posted August 17, 2007 What exactly is the difference between an H rated tire and a Z rated tire other than the obvious (H rated means 130 mph, Z rated means 150 mph). What is the difference in the construction? What is it that makes one tire rated to 130 and the other rated to 150? The reason I ask this is that there is atleast one tire out there (Pirelli Diablo) that is available in both ratings - if you know where to look and where to get them. I tried the H rated versions on my KTM Duke after running Michelin Pilot Powers (Z rated) and the difference in grip was incredible! The Pilot Powers simply would never get hot enough to offer the grip that the Diablos could offer after 5 miles of hard riding. I am becoming to believe more and more that tire performance has more to do with a tire operating at the correct temp than anything. A hot and properly up to temp touring or sport touring tire will actually offer more grip than a cold/cool high performance "occasional track day" tire. I am also coming to believe that each tire has it's own unique time and place. i.e., Pilot Powers are great on the track for a track day (not a competition situation) but are less than desireable on the street if you can't get them hot enough. A tire only offers it's maximum designed grip only when you can get it up to around 160-180° F. A tire that 160-180° F will be so hot it would burn your bare hand. It is part of our American thought pattern that we have to have the biggest, best, and "fastest" supposedly when it really isn't the fastest? Are we "over tiring" our bikes? I think the reason that multiple speed ratings are available in this country is two fold: 1. Motorcycle tire stores would have to stock more tires. 2. H rated tires are cheaper than Z rated tires. There are some squids out there who would go into Cycle Gear and buy an H rated tire for their Hayabusa simply because it's cheaper and then run them at 180 + mph (law suit, law suit, law suit). I'd like some input and thoughts from you other guys on this subject. A nice technical explanation from someone knowledge in tire construction would be appreciated also. Link to comment Share on other sites More sharing options...
turtlecreek Posted August 17, 2007 Share Posted August 17, 2007 a recent motorcycle rag article (dont remember which) tested some touring tires vs the pilot power type vs the race slick type. the 'pros' found that there was 'very little' difference in the grip at sane speeds and that only at the highest levels, did the race tires make a difference. they were genuinely suprised by how close things were and they definitely felt the race slicks were a LOW PERFORMER at street speeds/ conditions. bottom line is you are correct. for slow and go type riding, PP won't help much and touring tire lasts much longer. but i believe if you are running the twisties hard, you dont have to be running at race track speeds before the street legal 'race tires' become beneficial. my own impirical testing showed a HUGE difference in performance in touring Z6 and a sport M3. no, for 40% of my riding there was little to no difference, but when it mattered to me most, that being in a high speed curve on a back road in TN, the Z6 let me know more than once while the M3 or PPs have never so much as snickered. oh, and as for difference, it is the mix of rubber and synthetic that provides a different 'hysteresis' or as some call it a chemical grip. they are designed for different speeds to reach the different temps that they designed the tire to be at for a balance/maximization of grip and life Link to comment Share on other sites More sharing options...
Neboor Posted August 17, 2007 Share Posted August 17, 2007 I am becoming to believe more and more that tire performance has more to do with a tire operating at the correct temp than anything. A hot and properly up to temp touring or sport touring tire will actually offer more grip than a cold/cool high performance "occasional track day" tire. I am also coming to believe that each tire has it's own unique time and place. i.e., Pilot Powers are great on the track for a track day (not a competition situation) but are less than desireable on the street if you can't get them hot enough. A tire only offers it's maximum designed grip only when you can get it up to around 160-180° F. A tire that 160-180° F will be so hot it would burn your bare hand. :rolleyes: Link to comment Share on other sites More sharing options...
Member Contributer Stéphane Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 The H rated tire means that at 130 mph, the tire is capable of eliminating more heat than it accumulates. Past that speed, it would gain more than it is capable of shedding. So when cars/bikes are capable of sustaining that kind of speed for a period of time, they need higher rating. That would explain why your H tires get to operating temp quicker. Hope that helped. SG Link to comment Share on other sites More sharing options...
Baileyrock Posted August 17, 2007 Share Posted August 17, 2007 I don't have the answer on construction differences, but for street riding the H rated should be more than adequate. :thumbsup: Your comments on the PP don't make sense to me though, maybe it's just the Duke's light weight or something, but IMO the PP is simply the Best all around Sport tire currently on the market. I've put more than 25,000 miles of rippen twisties on them with zero complaints for wet/dry grip, warm-up, turn-in, braking etc. I also ride(fast) year round with temps as low as the 20's and have never had a grip issue related to the PP. Warm-up on the VFR requires about 60 sec. as they have never let loose period after the first 1000ft. I do like the standard Diablo though, even slightly better than the PP, but it doesn't last as long and offers me no real(slight) performance advantage. (actually the best wet tire I've ever been on) Like I said, maybe it's the on the Duke, but the PP is my favorite tire to date. :thumbsup: PS I do and have run race take offs on the street w/o issue(dry) Link to comment Share on other sites More sharing options...
Guest Posted August 17, 2007 Share Posted August 17, 2007 Guys: Thanks for the input and the technical explanation especially. I do ride the twisties hard. If you are familiar with North GA, I would have to ride the Duke on the edge from Morganton to Dale's on Highway 60 before the PP's would get enough heat in them before they started working correctly. Of course, keep in mind this is a 315# bike with 53 hp. When I switched to a Pirelli H rated Diablo on the rear and a DOT rated Avon ProExtreme Rain on the front, the tires warmed up quick and just ate up the twisties. On the VFR, I can get the PP's up to temp a lot quicker and they are a great performing tire - no bones about it. I guess the direction I'm headed in here is that the Pirelli on the Duke simply gives me a greater feeling of "confidence" and confidence is what going fast is all about. I've already installed a Z rated Pirelli Diablo on the rear of VFR. I am in the "pondering" phase of which front tire to install to go with the rear Diablo - an H rated or a Z rated. I do ride the VFR hard in the twisties in north GA and east TN. Grip and confidence are my two main concerns. If a tire last me one riding season, I'm happy with that. I ride three different bikes, it's hard to pile up a lot of miles on any one of them in a year. BTW, I have no intention of running the VFR over 130 mph. 129 max is plenty fast enough. The fun is in the curves anyhow. Link to comment Share on other sites More sharing options...
Member Contributer oyama Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 Talking about warming up street tires; do I have to warm up the sides to get the tire grip well? Or, would going straight for 3-5 miles would warm up the whole tire? Link to comment Share on other sites More sharing options...
Member Contributer kwr8728 Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 Oyama, i believe i have read somewhere that swirving on the road does little to nothing on warming up a tire. SO i take that to mean that you don't have to warm up the sides. After just a mile or so, the PP's seem to come into their grip and be good to go, turns or straights. I haven't tested the M3's yet on how fast they warm up. Not enough turns down here to try that! LOL. Link to comment Share on other sites More sharing options...
Member Contributer jeremy556 Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 No need to heat the sides of the tire. They will be what is heating up first anyway by way of sidewall flex. Link to comment Share on other sites More sharing options...
Member Contributer oyama Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 Thanks. So, it seems I do not have to worry about my first turn into the interstate 3 miles later after I left from home or work. :thumbsup: :rolleyes: Link to comment Share on other sites More sharing options...
Member Contributer jeremy556 Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 Probably not, if you are worried about, next time pull over to the shoulder before the turn, take your glove off and feel the tires to see how hot they are. Link to comment Share on other sites More sharing options...
Tightwad Posted August 17, 2007 Share Posted August 17, 2007 Hmm, I wonder what a non-contact thermometer would show, looking at the tire at speed. Could be a new farkle!!! Link to comment Share on other sites More sharing options...
Member Contributer ggathagan Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 Hmm, I wonder what a non-contact thermometer would show, looking at the tire at speed. Could be a new farkle!!! Remember mood rings from the '70's ? :rolleyes: Link to comment Share on other sites More sharing options...
Guest Posted August 17, 2007 Share Posted August 17, 2007 According to F Spencer, the best way to heat up tires is hard application of the brakes, not swerving from side to side. Link to comment Share on other sites More sharing options...
Member Contributer martinkap Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 According to F Spencer, the best way to heat up tires is hard application of the brakes, not swerving from side to side. Breaking or accelaration is the only way to heat up your tires as I learned from Jason Pridmore in the STAR school this weekend. Swerving from side to side does nothing - well maybe causes crashes of noobies... Martina Link to comment Share on other sites More sharing options...
Guest Posted August 17, 2007 Share Posted August 17, 2007 James Pridmore? How many kids did Reg have? I went to Reg's school at Road Atlanta several years ago. Great guy, great program. Link to comment Share on other sites More sharing options...
Member Contributer martinkap Posted August 17, 2007 Member Contributer Share Posted August 17, 2007 James Pridmore? How many kids did Reg have? I went to Reg's school at Road Atlanta several years ago. Great guy, great program. Hm - not sure how many kids he has but I did manage to figure out that he is married ... Oh well, if you mean how many of us were there then I think something around 50 people split into two groups: 'street' and 'advanced'... Great school, I learned a lot from many instructors plus as a bonus, Jason gives excellent hugs... Martina P.S. I did the 2up ride with him and it was one of the scariest things I did in my life. Link to comment Share on other sites More sharing options...
Guest COTU Posted August 18, 2007 Share Posted August 18, 2007 You guys are killing me. I'm going nuts trying to decide between the Diablo Strada and the Pilot power. Everytime I read something on here, my mind changes. I guess a good question is "what is going to make me a better rider?". I've been riding 3 years now, from Honda Silverwing (not the scooter,) CX500T, Yamaha FZR600, to the VFR for a year now on the Dunlop 220s. I have just worn through the rear, so I really need to make a good decision fast. The FZR had some Diablo corsas, but they were old and hard (even went down locking the front), so I never felt confident. The Pilots would be prime, but my occational ride to work (120 miles round trip), and some of the info on here is making me think about the Stradas. Help me out, I want to buy soon. Link to comment Share on other sites More sharing options...
Member Contributer jeremy556 Posted August 18, 2007 Member Contributer Share Posted August 18, 2007 You guys are killing me. I'm going nuts trying to decide between the Diablo Strada and the Pilot power. Everytime I read something on here, my mind changes. I haven’t ridden much on the stradas, but what riding I did on them I liked them. I didn’t get a chance to really push them, but I was dragging knees and pegs on the Cherohala on a bike I had never ridden and taking it easy with after about 3 corners. If I had any concerns about getting more mileage than a sport tire I would get stradas. Link to comment Share on other sites More sharing options...
Member Contributer Purvis Posted August 18, 2007 Member Contributer Share Posted August 18, 2007 . The Pilots would be prime, but my occational ride to work (120 miles round trip), and some of the info on here is making me think about the Stradas. Help me out, I want to buy soon. I went with Pilot Road because of my frequent commute to work, 80mi round trip. I have put 3k miles on them and have notice just slight wear on them. This past week went for a ride in the mountains with Gradus and they performed well. Link to comment Share on other sites More sharing options...
Guest Posted August 18, 2007 Share Posted August 18, 2007 Martina P.S. I did the 2up ride with him and it was one of the scariest things I did in my life. You're a brave soul. Was he as smooth as he preaches? I really liked his school although he did preach some rather "unorthodox" lines in some of the corners. He pulled me over twice for a "talk" and both times he would scream at me "Have you been to Keith Code's school or something". All in all, Pridmore is a great guy. The two things I got out of him the most were using your knees into the side of tank and being very, very, smooth. It's amazing how much you can steer a bike just by pressing your knees/inner thighs into the sides of the tank. Link to comment Share on other sites More sharing options...
shayne Posted August 18, 2007 Share Posted August 18, 2007 According to F Spencer, the best way to heat up tires is hard application of the brakes, not swerving from side to side. Breaking or accelaration is the only way to heat up your tires as I learned from Jason Pridmore in the STAR school this weekend. Swerving from side to side does nothing - well maybe causes crashes of noobies... Martina My understanding of waving from side to side, is that it is done primarily to scrub the surface of the tyre. Link to comment Share on other sites More sharing options...
Guest Jonchilds Posted August 18, 2007 Share Posted August 18, 2007 Tyres with higher speed ratings are also likely to have slightly thicker/stiffer sidewalls. At high speed, the forces pulling the tyre away from the rim may be greater than the tyre is able to overcome, and can cause the tyre to separate from the rim. There's also the issue of tread separating from the carcass at high speed, especially if the tyre is either very cold or very hot. It's not so much a problem with modern tyres on most bikes, as we rarely see 130mph on the street, but if you're in a top speed event or at the track, it's definately a consideration. Link to comment Share on other sites More sharing options...
Member Contributer Stéphane Posted August 18, 2007 Member Contributer Share Posted August 18, 2007 My understanding of waving from side to side, is that it is done primarily to scrub the surface of the tyre. . . . inside the rider's head. No real scrubbing will happen before the bike is put up to speed. But like as they say, if it helps your confidence, then do it. Still a lot of pro racers still do it, even though they've been told it had no real benefits. Link to comment Share on other sites More sharing options...
Baileyrock Posted August 18, 2007 Share Posted August 18, 2007 My understanding of waving from side to side, is that it is done primarily to scrub the surface of the tyre. . . . inside the rider's head. No real scrubbing will happen before the bike is put up to speed. But like as they say, if it helps your confidence, then do it. Still a lot of pro racers still do it, even though they've been told it had no real benefits. In car racing it's used to wipe crap/marbles off the tires that you may have picked up prior to the race start, I do the same thing to clean my bike tires if I've been in any crap. BTW you CAN scrub the surface by weaving side to side, I do and test it all the time. :thumbsup: Link to comment Share on other sites More sharing options...
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