Landracing Forum
Tech Information => Technical Discussion => Topic started by: javajoe79 on July 23, 2010, 05:26:01 PM
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Does anyone do this for some extra, if any, grip on the salt? You know how the dirt track guys use tire knives to groove their tires for given conditions. We have 12" wide hoosier slicks on the back of our car and I was contemplating cutting some grooves to help with traction kind of like this....
http://image.circletrack.com/f/10690311+w750+st0/ctrp_0810_05_z+dirt_racing_tire_prep+.jpg
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Personally I like some grove tread on a tire but I would be reluctant to run Hoosier slicks with 60 psi in them on the salt. If you have enough tread to put gooves in them it maybe too much tread for the speed you will be running which you didn't say. It just gives them places to chunk and come off.
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I think the 12" hoosiers are a bad idea right off the bat. I don't think cutting grooves will help any. This is just my opinion I have no technical data to back this up. Just what I've seen in the few years I've been attending salt events.
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We want to run over 250 eventually. I just looked at our stock of tires and not that it's much difference but the tires on there now are 11.5" and we have some 10" tires too. They are all relatively fresh tires with pretty much full tread depth left. We have been running them at 35psi at Maxton with 28" frontrunners... out front and the car was very stable. We went 205+ at Maxton with 7 total runs over and near 200 and they all felt great but grip isn't an issue there.
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Don't even try to compare the asphalt, concrete to the salt. Two different worlds and a much greater distance. Wide tires in most cases don't work. You can ask anyone who has spun on them in sports cars and other short wheel base cars. I have seen probably close to 50K runs at the lakes and Bonneville and have many stories on things that happen at those venues.
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Those tires will be an adventure on the Salt.
Better bring something narrower also.
FREUD
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I'm not trying to compare the two venues just adding info to the discussion. I know that wide is not good but I also know that at least one real fast car runs a 10" rear tire. Any thought on grooving tires for better grip FREUD?
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Like JD said they will chunk at speed or split down the groove.
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Group 44 Guy - Do yourself a big favor and listen to Glen Barrett . JD Tone and young Volk. All three have lessons and the experience of decades to draw from. I know it's fun to be a pace setter and try something "new" but even though it's called Speed WEEK the time goes really fast. You will be wasting time and runs trying to prove a point when proven tire combinations are available. Pat Kinne
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if ya feel like cutting tread in a tire.... Ill give ya my ex wife's address.... her life ins is paid up!...
Kent
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Thanks for the info guys. That is what I wanted to know.
No avatar guy. I am not trying to be a pacesetter or prove a point just wanted to know what people thought about it. There is no harm in a question. It's not like I declared that I would do it anyway in spite of what you all said. :cheers:
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I have no experience with the tires your talking about, but the ones we run work great at Bonneville. We have had many, many runs over 260mph with the 10 inch tire and quite a few runs in the 275-290 range. It may be that we have the correct set up for our car and maybe other do not, but we have never had any problems with the tire causing us to spin. :cheers:
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Does anyone do this for some extra, if any, grip on the salt? You know how the dirt track guys use tire knives to groove their tires for given conditions. We have 12" wide hoosier slicks on the back of our car and I was contemplating cutting some grooves to help with traction kind of like this....
http://image.circletrack.com/f/10690311+w750+st0/ctrp_0810_05_z+dirt_racing_tire_prep+.jpg
I've thought the same thing but would groove them more like a high performance street bike tire.
I just measured the wear holes on our ''too wide'' 10'' goodyear lsr tires .117 thousand, deep enough to groove and still rated for 300mph.
My cousin Arley drove a lakester for Les Liggett at El Mirage years ago with big agressive tires and the officials were not happy with the condition of the track afterwords :x
JL222
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Thanks for the input guys. You were who I was referring to about the 10" tires. :cheers:
From the guys who think they will chunk or split, why do you think that? Has this been tried and that is what happened? How long ago and what tires and how fast?
I would like to run a narrower rear tire but we are running out of time and money isn't abundant. We are coming to run regardless. I know we will learn alot too, and that is half the reason I like doing this stuff.
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javajoe... there is more to it than just wide tires we run a lot of weight in back ,soft springs and an instant center that does't shock the tires, my last measurement was 69% on rear wheels. Also the max spoiler length allowed.
Just got my new LSR frontrunners and the thread depth is .105 thousand.
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From the guys who think they will chunk or split, why do you think that? Has this been tried and that is what happened?
Its called tread squirm, which heats up the tires and start chunking. When we road raced we kept our rain tires at the bare minimum to dispel the water, otherwise the heat build up in the tread blocks would overheat the tires and start chunking. Tony
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To add to Tony's input. Each tread block has edges, each edge will heat instead of the heat being spread across the entire tread. As the tread blocks heat they will separate from the tire in our application.
DW
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javajoe... there is more to it than just wide tires we run a lot of weight in back ,soft springs and an instant center that does't shock the tires, my last measurement was 69% on rear wheels. Also the max spoiler length allowed.
Just got my new LSR frontrunners and the thread depth is .105 thousand.
Yeah I remember reading your posts about the suspension setup and weight. Thanks
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From the guys who think they will chunk or split, why do you think that? Has this been tried and that is what happened?
Its called tread squirm, which heats up the tires and start chunking. When we road raced we kept our rain tires at the bare minimum to dispel the water, otherwise the heat build up in the tread blocks would overheat the tires and start chunking. Tony
Ok good stuff. I too have experienced killing rain tires on a road course. I used to work at a racing school and during one of our race weekends we had a particularly bad case of chunking rain tires. It was up to the head instructor/race director to call for a red flag to stop the race for a tire change when it started drying out but he failed to do that and let the race finish. By the end you could see all sorts of chunks flying as the field came past the pits. It ruined every tire on all 20+ cars.
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To add to Tony's input. Each tread block has edges, each edge will heat instead of the heat being spread across the entire tread. As the tread blocks heat they will separate from the tire in our application.
DW
What about a pattern more like what jl222 mentioned. Large blocks, not unlike a drag radial or street bike tire? From reading up on dirt car tires and grooving, alot if it has to do with helping to shed heat. Or do you think that a tire without tread is just better for traction on the salt?
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I'm just an observer. I do think though that the more surface you put on the race track, tire blocks, will increase the heat build up, not shed heat. The larger the blocks the more surface area for heat build up.
IMHO.
DW
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So you think more tire, more heat, so narrow tire, less heat?
We have thought about skinnies on the back too. I know the Jesel truck ran what 240 or so with four front runners right?
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To add to Tony's input. Each tread block has edges, each edge will heat instead of the heat being spread across the entire tread. As the tread blocks heat they will separate from the tire in our application.
DW
What about a pattern more like what jl222 mentioned. Large blocks, not unlike a drag radial or street bike tire? From reading up on dirt car tires and grooving, alot if it has to do with helping to shed heat. Or do you think that a tire without tread is just better for traction on the salt?
The street tires I've seen just have a few grooves curving out to edge of tire with fairly wide spacing [not many of them] and I was surprised that is all they need in case of wet conditions. If I were to groove a tire for salt or dirt I would use at least double the grooves.
I also think a lot of heat buildup in LSR tires is from spinning ''skinny'' tires. Never have taken tire temps but have never noticed our
''wide'' tires being hot. Taking tire temps will be a new chore for one of our crew and I will post the results.
A certain competition coupe blew a ''skinny'' tire at close to 300 mph after spinning them to failure.
I said your spinning the tires going that fast, and he said everybody spins there tires.
We sold our Goodyear 10'' tires after 15 years and did not notice any change in the wear holes,now I wish I had measured them :roll:
JL222
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From the guys who think they will chunk or split, why do you think that? Has this been tried and that is what happened?
Its called tread squirm, which heats up the tires and start chunking. When we road raced we kept our rain tires at the bare minimum to dispel the water, otherwise the heat build up in the tread blocks would overheat the tires and start chunking. Tony
Tony... not many turns our the traction to heat up a tire on the salt, unless it's spinning.
What was the distance covered after the track dried before they chunked.
JL222
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I like the new avatar Dan. It describes exactly who you are! :cheers: :cheers: :cheers:
Pete
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Every time a tire chunks we have to do a course sweep to make sure the now out of balance tire has not shook so hard other pieces of the vehicle have come off. Dzus buttons come off as well as other items. Each time we do a sweep of the course it's usually about a 30 minute down time. Now another problem is the crews don't always notify the timing tower so we know. It's very important to do a quick inspection of the race vehicle and to let us know if anything including engine parts were left by your vehicle. When tire chunks etc. are on the course the next driver may see this and try to drive around the object. That can lead to other problems.
The next important thing is to make sure your crew attend the drivers meeting and understand what is going on as well. Do the course drive down on the course you will be racing on and understand why we do it.
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Are Hoosier slicks wrinkle wall tires? How would that affect handling?
-Chad-
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Any wrinkle wall will get you in trouble as they are designed to run at low pressures. Getting a little side ways can cause it to roll under the wheel.
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No they aren't drag slicks, so not wrinkle walls.