Took the car out Sat night, fresh Mickeys on it. Their website says to give them a solid burnout first pass. I did a bit longer than my usual burnout, (Get them spinning, quickly shift to high gear, 5,000 RPM, normally roll out of it after 2 seconds, this time went maybe 2.5-3 seconds). It was after sundown, ambient temp in upper 80's. Track was re-prepped just before my pass, (1st car in that lane).
60' was right about where I expected it to be, maybe off 2-3 hun on brand new slicks. Felt like they maybe hazed a bit early on, then hooked solidly rest of run.
Got back to pits, and looked them over, because I had gone down to a shorter 28" tire, and wanted to see how they looked, as I was basically guessing at what tire pressure to use. (Stiff-wall 10.5 tire, heavy car, didn't want to kill sidewalls on 1st pass, so went with 11.5 PSI). Contact surface looked really even across the tire, but the Right tire had 2 smooth "grooves" or lines on it, each about 3 inches in from inner and outer edge. (Not a physical groove as in a gouge, just a stripe around the circumference). Rest of contact area was slightly feathered, but these 2 lines were very smooth.
Left side tire had just 1 of the same line on it, toward the outboard side about 3 inches in. Tires are quite fresh, date code on both is Week 20 of 2018, which puts them mfd in middle of May.
They looked so strange, I loaded up that car after that pass.

Gonna try to post up some pictures here, anyone ever seen anything like this? I have not, in almost 30 years of racing. Any M/T guys on here that might comment, or PM to me? Thanks, afraid to run them again until I know what I am looking at...

Right side:


Left Side:


Date Code & Close-Up of stripe:



Can't tell if the pics showed up, here are the URL's for them:
Right: Right
Left: [/url]
Close-up & Date Code: [url=https://flic.kr/p/M18Ue2]3
4

This message has been edited. Last edited by: FootbrakeJim,

my first thought, the tires are rubbing something in the wheel tub.

quote:

Originally posted by Larry Woodfin:
my first thought, the tires are rubbing something in the wheel tub.

Larry, at first glance I thought maybe something was rubbing, although I couldn't imagine how. I had just switched from M/T 29.5 x 10.5 Stiffs, to 28.0 x 10.5 stiffs. Same wheels. These are 3/4" smaller (radius) at the tread than the old ones. There is nothing within 2.5 inches of the tires. I climbed underneath to make sure there was nothing hanging from in there, etc. I will try to get better pictures of them in the daylight.

I race a Stock Eliminator car with Hoosier CO7 Radials.

I have seen what you are showing before on my slicks when they are brand new.

All I can say is that after about 5 or 6 runs,they go away and work perfect.

Usually the lines are two on each side.

Heavy car (4020 pounds with driver) on 15 X 10 wheels .

I will be following this to see what some of the theories are.

Dan

Why so low on the tire pressure? I run 16 lbs in my bias 28x10.5's. That things gotta wad the shyt out of the tire.

I run 18 psi in my bias ply 29.5x10's, have accidentally had 20psi in them, mid 1.3x 60's in a 3300lb car, off the TB at 5000. No issues!

I would send some pictures to MT and see what they say. They may want to exchange them for you. They have always been good to me.

Maybe its just me, but I just put new M/T's on, 32x14, and first pass they looked a little weird to me also, threw it up to new tire and it being a test and tune where the track prep may not be normal. Made 5 more hits and tire looks as normal. I would worry after 5 or 6 hits IMO, not the first one.

quote:

Originally posted by Slick Vic:
I would worry after 5 or 6 hits IMO, not the first one.

Vic, I thought about doing that, but I know from this forum over the years M/T has been really good about taking care of the very few issues that have come up, even though there is no warranty on drag slicks. I was thinking if this did happen to be a fabrication issue, my chances of obtaining support from them would be better if I didn't put any more passes on them.

Anybody have suggestions on who to contact? I suppose I can call their tech line, probably be better than the Customer Service #, most C/S phone banks read the scripted response, (most likely would tell me no warranty on race tires).

Hey Scott & Mike - Are you both running bias slicks? Stiff sidewall, Wides, or standard?
What is your wheel width?
M/T Tech Bulletin #3 says to start at 10 PSI for a car over 3,000# with a tire under 30".
I was basically guessing, I had run 28's in the past, (Goodyears, Hoosiers, and Mickey's - but never stiff walls).
The M/T 29x10.5x15 Stiffs I have run for years, were happiest at 11.5 PSI, on these narrow 8" Weld wheels. When I ran 10" wheels, they generally liked 13.0 PSI. We all know the wider the wheel, the higher pressure you need to maintain the same contact patch, & vice-versa. I based that 13 # on 3 factors:
1. Actual contact patch - 10 years ago I had a flat, 75 foot long concrete driveway, (man, do I miss that! ). A splash of water & quick burnout would show if the pressure was too low, (2 thin, dark black strips at the outer edges); too high, (wide, lighter black mark, not as wide as the tire "tread"); or just about right, (nice even mark, full width of tread).
2. Appearance of tread surface immediately after making a pass, looking for even/consistent texture across tread face, minimal shredding.
3. Most importantly, consistent 60' times.
I am certainly planning to experiment with different pressures, and hoping to have my son get some video of the tires at launch, to see how much they are wadding up, then find the sweet spot for steady short times. I definitely know what severe tire wrap feels like, and didn't feel it on the 1 pass. Not saying they didn't get wadded up, and I do appreciate your comments, you both have had plenty of success and it helps to point me toward trying a higher pressure with these. I am all for shortening the learning curve using other folks' experience.

In the past I dealt with Jason Moulton, he got me a set replaced one time. Don't have a direct number for him but im sure if you called there tech support line and asked for him they could hook you up

My 3074 tires look similar to that first pass. Do not worry about it. All good.

quote:

Originally posted by FootbrakeJim:
Hey Scott & Mike - Are you both running bias slicks? Stiff sidewall, Wides, or standard?
What is your wheel width?

I've run the 28/10.5 stiff M/T and the same size Hoosier. Both on 8" rim. I saw some pics from Tulsa a few weeks ago, and it looks like I was wadding them up pretty bad even at 16 lbs. upper 1.30s/Low 1.40 60' at 3400#.


I'm going to 10" rim and 29.5/10.5 PBR over winter.

quote:

Originally posted by Scott Creed:
I saw some pics from Tulsa a few weeks ago, and it looks like I was wadding them up pretty bad even at 16 lbs. upper 1.30s/Low 1.40 60' at 3400#.
I'm going to 10" rim and 29.5/10.5 PBR over winter.

Scott, sounds like you are hitting yours a bit harder than I do. My ride is +200#, and .2 slower 60', (1.56-1.58). But I did find a picture of my old 29.5 stiffs, they were wadded up pretty good, so I am going to try going up to 15 or so on them and see what happens.

Update - M/T tech rep Matt was very quick to respond to my question, he said he thinks he knows what it is caused by, but he asked for pictures before giving his thoughts and advice. I sent them to him, and will share the feedback.

I had a brand new set of 3186's do that and they wouldn't clean up and would spin/shake even after 8-10 passes. MT guy looked and them and said there was an issue with the mold/manufacturer process and replaced them for me

Had new 3074s this spring. Friday night at Bandimere so not a lot of prep and Looked like that till I did one hell of a smoke show. Then worked great the rest of the year.

UPDATE - I wanted to share what the M/T Tech told me, after he shared my pictures with some of their other Motorsports techs.
"It looks like the tire actually was contacting the track during the run in those strips, but they may not be getting as sticky as the rest of the tread. I would run a few more times to see if that evens out. However, if performance and traction is fine, I don’t see that much of an issue with running them."
Mother Nature hasn't allowed me to try 'em out since then, hoping to this weekend, but forecast doesn't look too good at this point...