Tire Worn Out?

[ipscer]

I have been using Michelin's PR1/Power Race Mediums on my SV650, and find they work great. Other than a little bit of slippage powering out of a turn and a little bit upon turn-in before they get warm, I have never had any issue.

However, I am unsure how to determine if they are worn out. My concern is wether I am throwing them away too soon or not. I am not trying to get every penny out of them, but I would hate to think I am throwing them away half worn.

Thoughts??

Greg

[proechel539]

My thoughts are if you try and save money on tires it can get real expensive. Like my high side at VIR wich cost me two broken vertebrea and a lot of pain. I will be spending alot more on tires next year. Better safe than sorry!

[ipscer]

Hey Darrell,

Thanks for the reply.

I don't  think I am trying so much to save money on tires and I am trying to understand how to know when they have been worn to a point where they should be replaced. Obviously, there is a connection between cost and usage, although may primary focus is knowing how to know.

Regards,

Greg

[bigreid]

I get what you're saying Greg, you're not trying to stretch them by  any means, but you don't want to be wasteful.  I've wondered the same thing myself.

[251am]

  I was in the similar position with mediums. Polished areas like we find at MAM and Ginger. tend to REALLY slide the Mediums around. I switched to the PR5 rears and PRC front, and just closely monitor the wear, pressures, and take extra care of them with warmers and being clean.

Might wanna take a look at your suspension habits, too. Do you have notes on sag, rear ride height, pre-load, compression, etc.? 

  The Mediums are great for a tighter budget, but for the top %20 of competetiveness in either Ams or Experts the track distributors like Tom Mason and Edgar with the Michelin tent are your best bet for advice; 612-250-9122

[Super Dave]

However, I am unsure how to determine if they are worn out.

Well, you've got different issues on radial motorcycle tires.

Rubber is the direct contact to the ground, and that is what keeps you hooked up.

But the rubber also is insulation.

As the tire wears off the rubber, the insulating properties that the rubber has is reduced.  That allows heat developed by the load of traction or a tire warmer to escape.  In a tire that is used with out a warmer, it may never get to operating temperature, and so the rubber will never operate in its intended manner to generate good traction.

With a warmer, it might work for a while but then drop off.

By the time you get to the wear indicators, the ability of the tire to make good traction is really far gone. 

You can use it and use it and use it, per se, but the risk involved can be hazzardous to your pocket book or to your body.  Experinced riders usually have a better sense of feel for tire traction, so, often, they can get away with stuff.  Less experienced ones need good traction to cover some of their mistakes that might be costly. 

So, a tire will be worn out traction wise before it's physically worn out of rubber.

[ipscer]

Exactly!

I don't want to push tire to the limit because I may hurt myself, by bike or others; however, what are the signs that they are getting close to that point?

[ipscer]

By the time you get to the wear indicators, the ability of the tire to make good traction is really far gone.  So, a tire will be worn out traction wise before it's physically worn out of rubber.

I understand, that makes a lot of sense.

Can you give some indicators of how to tell when it as "worn out traction wise"?

Thanks

Greg

[Super Dave]

Well, it's a feel thing.

On a new rear, I expect that it will hold a certain amount of traction leaned over at full throttle on my 600.  When it begins to spin a little, not really going sideways at all, I know that I've used up the best part of the tire or that there might be a traction issue on the track surface.

It's pretty subjective. 

How much feedback you get is based on your chassis set up.  I've ridden bikes, mine and others, that have felt more like a wet sponge that didn't give me the feedback that allowed me to recognize that I, or the owner, was spinning up.  Usually, it was more of an indication that an event had happened and that now I was just receiving information that it was here and gone.

Regardless, you're only going to get a certain amount of "great" traction.  Then deteriorating from there.

Personally, I haven't liked the PR1 style carcasses on 600's.  The Power Race medium  isn't a race distribution tire, but, maybe someone knows, is the PR Medium harder than the PR5 from the race distribution line up?

[mq105]

I think a big part of this equation is how fast you are, and your riding style. In other words, how much are you asking of your tires? If you're running four seconds off the lap record you probably want to replace the tires sooner than if you're running, say, 15 seconds off at the same track. I agree with the opinion of erring on the side of replacing earlier. I came to that opinion the hard way.

[Super Dave]

Even beyond that though.  The faster you go, more of the full available traction will be used.  That means the tires WILL wear more, everything being equal.  You won't just want to replace them, you will be required to replace them sooner to maintain the same level of traction or level of safety margin for errors, etc.

[p3afoster61]

I have been told, and verified through experience, that in sprint racing, a tire will heat cycle its way out of usefulness long before being worn out.  Ask your tire vendor how many heat cycles their tires will take before turning to junk.  Also, many racers change the front more often than they need to.  You can often use two rears to one front. Count heat cycles!