REPOST: Tire technology.. ATTN: Jason C

Okay. Where were we? Here's a copy of your last reply... >It was my understanding that the tire compound had mostly to do with speed ratings. So, heat >is actually the main factor? The role of the belts are to keep the tire from flexing. Therefor, >generating less heat... > >I'm still missing something. I want my tires hot. I want them sticky, to grip the road. I also >want them somewhat flexible, where more tire is in contact with the road during a high-speed >turn. I seems to me, with the role of the belts as you explained, are defeating the pourpose of >what I want my sport tires to do??? Okay... first I must admit that I don't know everything. I sure wish I did, but it's impossible to learn everything after having been with Michelin for only 6 months. Here is my limited understanding... You're right, belts have to do all of that, and more. It's complicated! There are belts to help the tire maintain it's shape at high speed (consistent contact patch) plus there are belts to support the tire during high loads (cornering speed) plus more that I'm just unsure about. Here's where I'm making an educated guess based on what I've learned. To keep the tires sticky, there must be heat - but too much heat will grease a tire. A greasy tire is one that has so much heat applied that the rubber compound goes from a grippy substance to a slippery one. I would equate this to a reverse curing process - from semi-solid to semi-liquid instead of the the opposite. So how do we keep heat in the tire, but not too much? It's a relationship between the belt construction and compounding. If a tire flexes too much, too much heat builds up and greases the compound. To keep the tire "as it should" the belts try to limit the flex to only what is needed for a good contact patch - or a consistent one, throughout acceleration and lateral forces. Now we've got a tire that hypothetically rolls as it should. Now it's the compound's responsibility to warm up quickly and stay at optimum temperature. That's what the chemists do. An added note, if you have belts that help keep a consistent contact patch, you can use "harder" compounds for extra life while still maintaining high levels of traction. So... here's an example... the tires are cold on your car, you get it out on the track and "warm them up" with a quick lap. During the lap the tire has built up heat through it's own "hysteresis" (internal friction). Now I believe, once you get out there and start racing, the belts try to dissipate heat and the rubber tries to stay at optimum temperature. Here's where my knowledge runs out. I know that one of the reasons the belts are there are to maintain tire shape and therefore reduce internal friction and heat buildup. But the rubber needs heat to work, but not too much - so it's made to get to a certain temperature and then stay there. I guess if the belts do not do their job well enough, the rubber is heat cycled too high and therefore greases the tire. I've seen this alot on motorcycle tires that couldn't take it. (Motorcycles are where I get most of this info, but I'm sure it's the same for cars). There's more problems too, like we want the tire to absorb bumps, but still transmit major forces (cornering) to the suspension system. So we not only want damping but a spring force as well. I think I'm going crazy just thinking about it!!! It's all a really complicated relationship between steel and nylon cords, plus probably dozens of rubber compounds in the tire. There's not only the tread rubber, but sidewall, bead, internal, etc. etc. I hope this helps, and I hope I know more someday! Mark

GOTCHA!!!! HA HA

I bet you thought "What, who is this guy. What does he mean I'm wrong." I'm just joking...


You are backwards, though. I don't think it's that you should be on a quest for all the knowledge. It's more like you should be asking alot of questions. The knowledge will fill itself in. Our conversation stemmed from a debate over a nail puncture in a tire. And look at what I ended up finding out. If I was just looking for knowledge I would have stopped at the proper way to fix it. But, I continued to question, and ended up finding out so much more...

BTW, your explanation was excellent. Very cool, the way you were able to answer my questions in a way that I can completely understand, very good job.

Only 6 months, eh? I'm interested in knowing what it is exactly that you do for Michelin? What's your job title? What are you going to do with what you learn from this job???

Respectfully
Jason C

Got you too! Well maybe not. You sure had me there. I was thinking... okay, maybe
this guy is my BOSS posing on the A4 page to nab me. Whew!

Thanks so much for the complement. You're right, the best way to approach things is to ask many questions. That's how I've learned what I know so far. I just feel out of place doing it, because my job doesn't relate directly to tire design. So I try to be careful not to look like I don't like my job! Sometimes I feel like I ask so many questions I need to stop...

My actual job is in mold design, where we get the tire tread design from R&D and decide how to manufacture the tire mold. I'm lucky to be where I am because I have access to tire design knowledge, and I can learn from the designers and Michelin's own information. If I were in sales for example, I wouldn't be able to learn what I have as easily!

I really like what I do! It's really interesting, and really cool to see the new tires coming through that no one knows about or may never know about. I'm not sure where I'd like to go - first and foremost I want to learn as much as I can about my job and perform well. If I had the opportunity, I'd be very interested in tire design, and testing sounds awesome! I'm also a big motorcycle fan, and something on that side of the company sounds interesting too..

We will see where I go. I certainly want to learn more about tires. Hopefully I will always be able to...

Okay, so what do you do for a living?

Mark

I'm in retail of High-line and Exotic cars. I'm only 25yrs old, so I have a long ways to go and I'm taking it step by step. I'm don't want to rush anything. Lately, I've experienced licensing problems, so it's put a delay on things. I'm trying to build a network between Florida and Michigan, and on the net. It was only recently that I was able to get a restart, and start developing a solid plan. I'm just taking my time and asking alot of questions. I really want to focus on evolving the dealership, and focus on where it stands in the near future. With all the new networks, and an overall new way of doing business, a dealership be be that much more. It needs to adapt, and I'm going to be there when it does...

I took it as a compliment when you mentioned you thought I may be your boss. I'm working on being one...