Dunlop L Racing Tire "Break In"?

[John_W]

Dunlop L Racing Tire "Break In"?

Hey folks,

I'm running the Dunlop bias ply racing tires (L) and just looking for some thoughts and opinions on whether there are tire "break in" procedures that you all think will extend the tire life appreciably. I've read some things about the importance of the first heat cycle with respect to long term tire life and would appreciate your experiences. My question is specific to Dunlop bias ply racing tires but I imagine it also applies to the Hoosier TDs as well.

Any thoughts?

Thanks - JW

 

[dougie]

Re: Dunlop L Racing Tire "Break In"?

John -

I run bias-ply on my vintage racer, usually Hoosier Vintage TD's, but the Dunlop L's and Good-Year Blue-Streak should all be"broken-in" the same way. I use this method and have found I get at least 1-2 more weekends out of a set of race tires (4-8, 20-minute races) then when I didn't. It does depend on the weight of you car and the tracks you run as well. Here's the procedure: https://www.racetire.com/products/tctips.htm#Tire%20Break-In%20Procedure

I also jack up the car and remove the tires after the initial break-in run, storing them in the shade or out of the sun in the trailer. I do let them sit a minimum of 24 hours often longer. I have 1-2 sets in the rotation at all times.

[img:center]
PNWH12_DJS-1778 by dougescriva, on Flickr[/img]

 

[John_W]

Re: Dunlop L Racing Tire "Break In"?

Dougie,

Thanks for the response. I had read this before but was looking for some verification that this procedure works as described. I'll try it but I may have to do the first heat cycle in a local parking lot or something. I'd like to get the new tires prepped before I get to the next rack event. I'll have to think about where I can do that .....

 

[aeronca65t]

Re: Dunlop L Racing Tire "Break In"?

I do not see anything mentioned in the link, but generally I think it's a good idea to drop the pressures when tires are stored.

With the Toyo R888, they actually warn you that the tires can crack if they are left over the Winter at full pressure.

But even with bias tires, I'd store them at about 15 psi or so (off the car, of course).

Also, the notion that one should <span style="font-style: italic">increase</span> tire pressure for rain seems counter intuitive to me.

 

[dougie]

Re: Dunlop L Racing Tire "Break In"?

Niels -

Good call on the lowering the pressure during storage. I do increase my tire pressure, usually 1-2 psi during rain races because they don't generate as much heat and "grow" as they do in the dry. This is for the bias-ply only.

 

[Michael Oritt]

I just installed a set of Dunlop 204's on t he MK IV and in researching the best way to break in the tires I ran across this old thread which was quite helpful.

The article that Dougie posts is quite informative but since I do not have access to my own test track I am limited in how, when and where I can follow the procedure suggested several days prior to an event.

This evening around 6:00 PM I pumped the tires up around 5 psi over normal pressures and trailered to the local high school where there is a very big parking lot with absolutely no obstacles or curbs. I quickly unloaded the car and began running several series of fairly tight circles, both clockwise and counterclockwise, first at moderate and then at higher speeds. After each run of five or so minutes I stopped and checked tire temps. The tires were at 77 degrees when I started, and after the first run they were at around 100. By the time I finished the third and final set of runs the tires were between 125 and 130 degrees, which is quite a bit hotter than I normally read when I come in from a session.

In any case I stopped at that point and the tires will now "rest" until next week's Jefferson 500. Let's hope I get the increased tire life/performance that the Hoosier folks promise.

 

[Elva164]

Nial, increased tire pressure in rain also allows the tread to "stick out" a bit more prominently and not squish as much during cornering, allowing more water to pass inside the tread and away from the contact patch.

Edit: You know, if you've been wondering for the past year or two...

 

[aeronca65t]

Edit: You know, if you've been wondering for the past year or two...

LOL!

To be honest, I don't really change tire pressures in rain anyway.
Overall, I guess it "bulges" the tire more and reduces contact patch size...which might "knife" though the puddles better.

I think it's hilarious that Mike took his race car for spins at the local high school. If I did that at the high school near me here in NJ, the coppers would lock me up!

 

[Michael Oritt]

Nial--

The result would probably be the same here. I'm not being critical of police but the friendly cop who would likely turn a blind eye to such an activity seems to have become extinct and nowadays our police forces are populated by extremely professional ex-military types who have had their senses of humor trained out of them.

Some of you may know that due to a major screw-up on Dunlop's part the factory where they produced vintage tires has closed and as of this writing L-series tires are not available and will probably remain so for the balance of the season. All of the groups with whom I race (VSCCA, VRG and SVRA require that I use ONLY Dunlop L tires and though SVRA does permit the softer 484's they too are like hen's teeth. So the question becomes whether vintage sports racers will be able to use an alternative tire such as Hoosier TD's or will this segment of the racing population be forced to observe from the sidelines? I have managed to put aside a spare suit of tires and it could be that I will be a frequent class winner later in the season if only because I will be the only registrant!

 

[Elva164]

I have managed to put aside a spare suit of tires and it could be that I will be a frequent class winner later in the season if only because I will be the only registrant!

You always find a way to the front.