Ok i got a couple questions on tires because im kinda new on tires and ive never had to replace any. My bike had 10,000 miles on it when i bought it and it came with a Michelin pilot power for the rear and i think stock dunlop 207 on the front. Well i hear these pilot powers are sweet but i havent really rode agressive enough to test it, but she has done everything i have asked so far. What im wondering is how do i know when the tire is shot, because its still got the tread groves and all and it looks good to me but its also kinda a race grip tire so im not sure how to judge without having past experience. Also, I have no clue of the tires milage cause the guy i bought it from doesnt know anything about this bike. Is their a tread depth measurement or anything to go by? Also, I think im gonna switch my front d207 to a pirelli diablo because even with the way i ride, the front tire feels like somebody rubbed sex jelly all over it. Is it cool to be running a pilot power rear and a diablo front or does that mess things up a little?

Here's my limited knowledge:

you can tell a tire's relative mileage by the tread depth/wear bars. (bars that run horizontally across the tire and can be seen between the tread). If the tread depth gets even with the wear bars or below them, you're probably on the side of the road. If you've got an 1/10" of tread or more over the wear bar you're ok for a while.

as for running different brands of tires front and rear, the only down sides I know of are different amounts of time to warm up and possibly different stickiness. On the other hand, I hear running pilots is the way to go on an R6. (I am buying some for mine as soon as the rain dies 8)

Tire manufacturers desing their tires to be run as a matched set. The profile and handling characteristics of a rear to tire will compliment that of the same company's front tire.

Now if you know more about tires then you could mix and match the different advantages of certain tires from different companies to fit how you are trying to ride.

An example of this is that I'll put a stickier more aggresive tire on the front at certain tracks because I need to corner hard and the harder rear tire allows me to get on the stick hard without the risk of ripping up the back tire.

If you are riding mainly or solely on the street I would highly recommend getting a michelin to match your rear tire.

First of all d207s are crap. They feel like you're riding on wooden wheels. They don't inspire confidence in the twisties. They suck. Michelin's are nice tires. Pirelli makes good rubbers, but if you want to switch to Pirelli I'd get a set so they match. At least until you have some tire knowledge under your belt to determine what is good for you.

Oh, and how to tell if you tires are shot. If you ride on the street a lot you'll develop a flat spot on the rear tire. This comes from riding too much with the bike up and down and not enough riding while leaned over. If you run your hand across the tread from rim edge to rim edge you'll feel that the tire is curved near the edges and squared off in the middle. This isn't good. You should think about replacing the rear tire. The primary reason is that the bike will no longer handle the way the tire and the geometery were set-up to do. And as far as tire life goes... you should be able to get 1 front to last through 2 rears.

hey fiero, what about cracks in the tread? For some reason my front has a bunch of light cracks in the treads (but still has a lot of tread left). The tires are old but have hardely any miles on them...

cracks are bad. This is a sign of dry rotting. Since you can only see the outer edge of the tire shell you can't determine how bad the carcass of the tire has eroded and been compromised.

I would ditch the front tire as soon as you can. Motorcycle tires often lose the performance envelope before they run out of tread. The rubber compound is made with oils that release over time and help keep the tread soft. This helps the tire be sticky and make you go fast. But as the tire gets hot and cold from the ambient air, or from you riding and heating up the tires, or just from evaporation these oils leave the tire. And once that has happened you should replace the tire.

There really isn't any way to gauge whether a tire is still soft. You can push a finger nail in and see if it still squishes, but knowing how much it bends compared to how much it should bend only comes from burning many many sets of tires.

I've got 25k miles on my bike. And I've probably smoked 15-20 sets of tires. I've also had street tires (michelin pilot sports which they don't make anymore) last 6k miles with good even riding and making sure you get some good twisties in to keep the tire round and not square in the back.

So my best suggestion is to replace the tire. A) you'll be happy with the better performance B) you'll be better off with a safer tire C) front tires aren't that expensive. Once you've gone through a few sets you'll be able to tell what's good and what's not, and what you want out of a tire or set of tires.

Tire manufacturers desing their tires to be run as a matched set.

Okay I get that but where is all of this going?

Tire manufacturers desing their tires to be run as a matched set.

Okay I get that but where is all of this going?

It's going towards getting a matched set of tires and riding on them until you have enough knowledge under your belt to deviate from what tire manufacturers suggest.