Interesting Read

Crash · 10-23-2003, 11:25 AM

Kinda Sketchy

*okay so my text must have been edited out**

Just basically an article about problems with Dunlop.

Crash · 10-23-2003, 11:31 AM

Kinda Sketchy

This is from AMA Superbike.com and it's a little frightening to think that Dunlop isn't focused on the proper issues. *There is a lot of back peddling in this interview, but it gives credence to the fact that there are problems with Dunlop. *Personally I've never had a Dunlop tire I trust.

From their sport tourer D205 to the 208 GP A's I just don't like them.

Also, who else thinks that we need to stop racing at places like Daytona, Cal Speedway, PPIR, any place with concrete walls on the tack?

Serial Thriller · 10-23-2003, 11:35 AM

That has happened in other forms of racing too (not Dunlops). As the vehicles get faster, the tire technology can't keep up. What usually happens is the vehicles are restricted to match the capabilities of the available tires.

Crash · 10-23-2003, 11:56 AM

I understand that, but he admits that they are not paying attention to the issue. Malidin's quote is a testament to that and the fact that he agreed with it, shows that they aren't focused.

tigerblade · 10-23-2003, 12:00 PM

Sounded to me like Allen thinks they've been focusing on placating the racers too much instead of taking a hard look at the engineering.

He's right about them having almost the full grid in AMA, so any problem will likely be a Dunlop problem, but that doesn't explain the lack of failures in other series.

luvtolean · 10-23-2003, 12:01 PM

I think they're focused, but they haven't been focused on keeping the tire from blowing.

Dunlop's new slicks, especially the 'good stuff' (ie, the stuff that is hard to impossible for a privateer to get) are much lighter. I think they've been driven by other tire maker's (michelin) coming out with light tires. Maybe they didn't study this well enough and removed strength making the tire light. The 16.5' tires also have a lot more sidewall, which is going to lead to more flex....leading to more heat...and the new rules mean a lot more people have lots'a power. It's a vicious circle.

Baketech · 10-23-2003, 12:02 PM

Quote:

Crash : I understand that, but he admits that they are not paying attention to the issue. *Malidin's quote is a testament to that and the fact that he agreed with it, shows that they aren't focused.

I wouldn't exactly agree with that. I would put it more in the category of self-deprecating customer flattery.

I'm sure Dunlop engineers are well aware of the design parameters.

This is just the kind of things that reps say when they are on the record.......Public Relations 101

Crash · 10-23-2003, 12:42 PM

So as a tire manufacture, would you guys cater more to the rider wanting traction, or would you as he put it 'This is what we have and you are racing with it'? *

I mean wouldn't you rather have a reliable tire as a manufacture. *When you have such highly publicized blowouts that isn't good for your Public Relations....

tigerblade · 10-23-2003, 12:58 PM

I think I would point to Mladin and Spies' catastrophic tire failures and tell the rider, 'this is at the limit of what we can do. We'd like to give you a little bit lighter tire, but we feel we've gone as far as we can before we compromise safety.'

Baketech · 10-23-2003, 1:05 PM

Tire science is empirical in nature, so it follows that development is probative...

tigerblade · 10-23-2003, 1:11 PM

I can understand it being empirical in regard to the 'feel' aspect, but wouldn't the heat/stress threshold be more absolute?

Baketech · 10-23-2003, 1:26 PM

Quote:

tigerblade : I can understand it being empirical in regard to the 'feel' aspect, but wouldn't the heat/stress threshold be more absolute?

Because the elastic modulus can change dramatically at different flexure frequencies, I'm guessing not...
(BTW, this would go a long way toward explaining the different performance on different bikes....think power delivery)

I think they are at the pointy end of the envelope, and it requires a ton of iteration and data collection to come up with workable calcs.... just my 2 cents...

tigerblade · 10-23-2003, 1:30 PM

I defer to your engineering knowledge. I would still think that for the given materials and conditions that it could all be extrapolated. Guess sometimes you've just gotta test it and see what happens, huh?

Crash · 10-23-2003, 1:46 PM

I think that on a track by track basis you can get that data out. in re: Heat/stress. The manufactures pretty much tailor the tires to specfic tracks like Daytona. It's very easy to obtain the data on that track and focus on a compound for it.

Would the flex and temps rates be the same for the same track? I know ambient temp and track temp and whether or not the rider had a burrito that morning all factors in, but you could still find the mean and test around that mean?

Baketech · 10-23-2003, 1:53 PM

There's a big diffence between extrapolation inside the observed data set, and outside of it.....lots more unknowns.....especially on a race tire that becomes a 'living' creature at temperature.

tigerblade · 10-23-2003, 2:01 PM

We have some pretty good examples of failures. *Would those serve as an 'outer limits' point for the observed data set? *Of course, Allen indicates that they still don't know what went wrong with Bostrom's tire in 1998...

...and then the tire construction/composition is constantly changing so the date for one combination probably won't be relevant to a new combination...

Hey! Maybe this stuff isn't so easy? Still, haven't seen these problems in WSB or MotoGP. Given, the weight of the MotoGP bike is probably a factor, but the WSB machines should be comparable?

luvtolean · 10-23-2003, 2:21 PM

Topics were merged.

Crash · 10-23-2003, 4:36 PM

Quote:

tigerblade : We have some pretty good examples of failures. *Would those serve as an 'outer limits' point for the observed data set? *Of course, Allen indicates that they still don't know what went wrong with Bostrom's tire in 1998...

...and then the tire construction/composition is constantly changing so the date for one combination probably won't be relevant to a new combination...

Hey! *Maybe this stuff isn't so easy? *Still, haven't seen these problems in WSB or MotoGP. *Given, the weight of the MotoGP bike is probably a factor, but the WSB machines should be comparable?

The only example of a tire failure like we've seen in the AMA, to happen in MotoGP that I can remember was Rossi's rear last year at Le Mans (I think). His rear tire completely delaminated.

tigerblade · 10-23-2003, 4:48 PM

Yep. *And that's one. *From AMA this year we have at least Spies, Mladin, and isn't that what happened to Brian Livengood too? Oh, and Kurtis had a problem at VIR while leading?