[The CyberPoet]

Thank you for your input. I do check the pressure regularly. I was hoping it may be that some tires just do it. Take care.

Remember, these are NOT the OEM tires for your Kat, and as a result, the tire pressures recommend by Suzuki in the owner's manual and on the sticker on the swingarm are not directly applicable.

Furthermore, tire pressures for the Kat's safety stickers are listed as minimums for a 140 lb (wet, geared-up) rider riding solo on the Macadams (98+ Kat 600) or Dunlop 205's (98+ Kat 750). Most riders weigh quite a bit more than that, esp. with cargo/passenger/gear/etc.

Let's do a little though exercise that a Metzeler engineer once taught me (this is not verbatim, but covers the same points):

Imagine the bike sitting there on the tires set to their minimum pressure and with no rider on the bike. Think about the size of the contact patch and how much the bottom of the tire is flattened out at that point. Got it so far?
Good...
Now we know how the tire builds heat for modern tires is controlled (literally) by how big that deflection patch is (and the angle the belts/carcass deflects to hit the contact patch and come back out of it)...

Now imagine what's going to happen to that tire once you add on your weight to it. The patch will get bigger, the angles of the tire coming into and out of the contact patch will be larger, and the tire will run hotter as a result. This extra heat and the extra drag as the rubber chunks deform/reform as they come into/out of the contact patch is what causes tires to cup and scallop.

The right answer is to increase the tire pressure to keep the contact patch (and the angles leading into/out of it) the same size with you on the bike as it had been at minimum pressure with you off the bike. Doing this will put the tire back into the right operating temp and will prevent cupping/scalloping (and if existing cupping/scalloping isn't too bad, may wear the tire back to even). And because the tire is now back to the shape it was engineered to be, handling should improve significantly AND tendency towards hydroplaning in the wet will decrease at the same time.

This is why most aftermarket tire companies recommend a higher baseline pressure for the Kats than Suzuki does. Pirelli and Metzeler both start off the both the front & rear at 36 psi and tell you to increase from there as needed (generally 1/2 psi for every 50 lbs of load weight on the front, a bit more for every 50 in the rear, so a 200 lb rider would run 37.5 - 38 at the front, 38.5 - 39 at the rear).

I don't know what Bridgestone's specific recommendations are, but I can tell you that if the tire is cupping out, the tire pressure is (by definition) too low for the total weight on the tire, and it's running hotter than it should as a result.

Cheers
=-= The CyberPoet

[steves]

I had battle ax's on the Bandit, and the front cupped too almost no matter how much pressure I ran.

[The CyberPoet]

My experiences with them are that they are really designed for cooler weather than Florida's roads in anything approaching summer (ditto every Dunlop I ever tried on the Kats) and as a result, need less input to get past their operating temp range and start shedding rubber/scalloping/cupping, esp. with a heavy bike like a kat or a bandit. I could easily see how this would be a benefit to riders in cold areas, at the price of riders in warmer climates.

Cheers
=-= The CyberPoet

[justyn]

This is somewhat off topic, but not entirely. My front is cupped from the PO. It doesn't appear to be too bad. I'd like to get the rest of the season out of the tires, because I see no dry-rot and the tread is in otherwise good shape.

My experiences with them are that they are really designed for cooler weather than Florida's roads in anything approaching summer (ditto every Dunlop I ever tried on the Kats) and as a result, need less input to get past their operating temp range and start shedding rubber/scalloping/cupping, esp. with a heavy bike like a kat or a bandit. I could easily see how this would be a benefit to riders in cold areas, at the price of riders in warmer climates.

My question is based on that statement. The Metzeler Z6's seem to be the bee's knee's from what I read. Would that be true for all climates? I know CP likes them, but he's in Florida, and Wisconsin weather is a bit different. Plus I like to start riding February/March, and ride until November/December, where morning temperatures are well below freezing. (it was below freezing on my way in two days ago ) I will qualify that statement with most of my rides in that cold of weather is a 20 mile one way commute.

[steves]

My question is based on that statement. The Metzeler Z6's seem to be the bee's knee's from what I read. Would that be true for all climates? I know CP likes them, but he's in Florida, and Wisconsin weather is a bit different. Plus I like to start riding February/March, and ride until November/December, where morning temperatures are well below freezing. (it was below freezing on my way in two days ago ) I will qualify that statement with most of my rides in that cold of weather is a 20 mile one way commute.

No problems here with the Z6, but I quit riding after the salt starts going down... and don't start until after it's been washed away.

The Z6 is engineered in Germany where many people ride in the winter

[Shifty]

My stock front Michelin Macadam cupped badly as well. Never could figure it out.

[thetable]

My question is based on that statement. The Metzeler Z6's seem to be the bee's knee's from what I read. Would that be true for all climates? I know CP likes them, but he's in Florida, and Wisconsin weather is a bit different. Plus I like to start riding February/March, and ride until November/December, where morning temperatures are well below freezing. (it was below freezing on my way in two days ago ) I will qualify that statement with most of my rides in that cold of weather is a 20 mile one way commute.

I haven't ridden the Z6 in the cold, but I have ridden it's brother the Strada, which from everything I can tell is nearly identical. They do tend to get a little hard in the cold temps (Sub 40), and they never come up to temp, but the ride quality is indicative of that. If ridden with respect, I had no problems with them. I spent a fair amount of time this winter in the teens + on the Stradas. I've even ridden them in the snow a few times. This winter I will probably go with a more dualsport oriented tire, since they tend to be of a softer rubber compound designed to operate at lower temps.

[The CyberPoet]

My question is based on that statement. The Metzeler Z6's seem to be the bee's knee's from what I read. Would that be true for all climates? I know CP likes them, but he's in Florida, and Wisconsin weather is a bit different. Plus I like to start riding February/March, and ride until November/December, where morning temperatures are well below freezing. (it was below freezing on my way in two days ago ) I will qualify that statement with most of my rides in that cold of weather is a 20 mile one way commute.

Florida does get cold in Dec-Feb, and I have ridden them in the 30's & 40's, and although they took about three times as many miles to heat properly, they did come up to temp for me here in mid-January at near-freezing on the Kats. Note that Florida's coldest periods is a very dry cold, so heat loss is lower than it might be with snow or rain in your area. Lower the tire pressures slightly will also cause the tire to run hotter, which makes sense in the worst of weathers.

One thing to think about and that's even if you ride a sport-bike: the tires need to operate in their operating temp range to work correctly. In very cold weather (say below 45 degrees F), even with a 1k SS bike, you're not going to get a set of sport tires into their operating temp range away from a race track or serious canyon carving -- so in cold weather, sport-touring or just plain touring tires actually have a benefit, because their operating temp range is lower and is easier to successfully hit.

Cheers
=-= The CyberPoet