Discussion
There are a lot of thoughts around what causes tyre shake, but no real definition of what it is (as far as I am aware)..
So what are your thoughts? Is it that the tyre "footprint" begins to overtake itself causing the flap or is it something else? Whaddya think folks?
slinky
587racing.com
So what are your thoughts? Is it that the tyre "footprint" begins to overtake itself causing the flap or is it something else? Whaddya think folks?
slinky
587racing.com
from seeing that 1000fps slo-mo NHRA video it seems to be when there isnt enough power put to the ground and the tyre doesn't slip enough (in top fuel anyway) so it slips, grabs, slips, grabs and the tyre hits a resonant frequency or anytime the tyre slips and grabs
from what I've gathered anyway, experts feel free to correct me
from what I've gathered anyway, experts feel free to correct me
so you saw Erica Enders horrendous shake tonight as well...lol
Tyre shake is generally thought to be caused by the tyre getting to much grip and trying to fold over itself.Tyres work well with the tyre just turning over the surface..if it grips too hard part of it stays stationary and the rest tries to carry on therefore "rolling" over.Cure is generally gearing,clutch tune,shock tune..it can be just one or all three..
worst shake i've seen here in a while was Andy Kirks at Shakey...before that it was Andy Robinson also at Shakey...both blurred my vision from the stands!!
Tyre shake is generally thought to be caused by the tyre getting to much grip and trying to fold over itself.Tyres work well with the tyre just turning over the surface..if it grips too hard part of it stays stationary and the rest tries to carry on therefore "rolling" over.Cure is generally gearing,clutch tune,shock tune..it can be just one or all three..
worst shake i've seen here in a while was Andy Kirks at Shakey...before that it was Andy Robinson also at Shakey...both blurred my vision from the stands!!
redvictor said:
Tyres work well with the tyre just turning over the surface..if it grips too hard part of it stays stationary and the rest tries to carry on therefore "rolling" over.Cure is generally gearing,clutch tune,shock tune..it can be just one or all three..
Hi Andy & the other experts !
When I look at -good- dragrace photos,
I can clearly see that the tyre is not just "running over the surface".
(On some Pro Pix you can see tyres that are NOT round, but very distorted,
even square or triangular, seen from the side)
Because it would not have enough of a "contact patch" between the rubber and the track,
so I think the teams are trying to have something like a "controlled unbalance" of the tyre,
to "throw" a large chunk of rubber "in front" of the contact patch,
to enlarge the contact surface and get more power to the ground.
If this works well, and evenly on both tyres, it will be a good run.
But if the "unbalance" gets uncontrolled, or uneven on the 2 driven wheels,
then the trouble -and tyreshake- starts, at least that´s what I am thinking.
But that´s just my 2 cents from the wrong side of the guardrail.....
So let´s shake, rattle & roll further in this thread !
Benni
I've watched slo mo videos in which the shake appears to be from side to side. Frank Hawley has also written that tire shake happens if the tires hook up too early in a run, and that the way to avoid tire shake is to apply more power and keep the tires slipping longer.
I met Brendan Murray at a nostalgia race here in the states and he swears that he's ran the same 9" Ford STREET gear in his blown nitro front engine dragster for two years. He says that he gets away it because of the car's narrow tires and a soft clutch setting. When I told him that I was putting together a nostalgia nitro funny (which has to have big tires to fill the wells or it'd look ridiculous), he said to run a pro gear and check it often because we'll be hammering the gear with shake occasionally.
Here's what I believe is most likely. I think shake happens if ONE tire hooks up too soon. Watch how many degrees a wheel can rotate within the sidewalls at launch on super slo mo before the car even starts to move. If one slick hooks up, that wheel is going to wind that sidewall up tight the same way. Meanwhile, the other tire is still spinning, but they're both connected via the same live axle. I think that just before the one tire snaps loose again after the sidewall windup, the other tire now decides to stick (probably because it might have slowed down a bit as the other sidewall gets tight). From there I think it's just a series of both tires taking turns hooking on their own and letting go. I can't think of anything else that makes sense.
I think that applying more power and keeping them slipping longer gives them a chance to more gradually even themselves up before sticking.
www.break.com/index/drag_racing_filmed_at_1000fps.html
I've downloaded this next vid to my pc, then played the already super slo mo launch at half speed on Windows Media Player. If you do the same you'll see some amazing things. Watch how the sidewalls wind up, then the tires "snap" loose one time before tightening up AGAIN. Then the tires start slipping (apparently not gripping and snapping like the first time due to the wheel having some momentum now?)and the car begins to move forward. Look at how much the outside diameter of the tire reduces as the sidewalls wrap up before the tread snaps loose. A lot of dynamics there to try to wrap your brain around.
www.whoisthemonkey.com/videos/dragstercrashcompilation.wmv
I met Brendan Murray at a nostalgia race here in the states and he swears that he's ran the same 9" Ford STREET gear in his blown nitro front engine dragster for two years. He says that he gets away it because of the car's narrow tires and a soft clutch setting. When I told him that I was putting together a nostalgia nitro funny (which has to have big tires to fill the wells or it'd look ridiculous), he said to run a pro gear and check it often because we'll be hammering the gear with shake occasionally.
Here's what I believe is most likely. I think shake happens if ONE tire hooks up too soon. Watch how many degrees a wheel can rotate within the sidewalls at launch on super slo mo before the car even starts to move. If one slick hooks up, that wheel is going to wind that sidewall up tight the same way. Meanwhile, the other tire is still spinning, but they're both connected via the same live axle. I think that just before the one tire snaps loose again after the sidewall windup, the other tire now decides to stick (probably because it might have slowed down a bit as the other sidewall gets tight). From there I think it's just a series of both tires taking turns hooking on their own and letting go. I can't think of anything else that makes sense.
I think that applying more power and keeping them slipping longer gives them a chance to more gradually even themselves up before sticking.
www.break.com/index/drag_racing_filmed_at_1000fps.html
I've downloaded this next vid to my pc, then played the already super slo mo launch at half speed on Windows Media Player. If you do the same you'll see some amazing things. Watch how the sidewalls wind up, then the tires "snap" loose one time before tightening up AGAIN. Then the tires start slipping (apparently not gripping and snapping like the first time due to the wheel having some momentum now?)and the car begins to move forward. Look at how much the outside diameter of the tire reduces as the sidewalls wrap up before the tread snaps loose. A lot of dynamics there to try to wrap your brain around.
www.whoisthemonkey.com/videos/dragstercrashcompilation.wmv
Edited by Nitrohaulic on Friday 24th November 02:01
That is an interesting theory certainly, and would be consistent with the characteristic "caterpillar tracks" seen on the track after bad shake. This relates then to an article I was reading about tyre pressures and widths recently, which refuted the conventional wisdom that a wider tyre gives you a bigger contact patch - effectively a simple application of pressure=force/area, it simply means you have the same contact area in a different shape - a wide tyre gives a wide but short contact patch, whereas a narrow tyre has a long and narrow contact patch.
Clearly that is just a static analysis and the dynamics are a lot more complex, but worth mulling over nonetheless.
Clearly that is just a static analysis and the dynamics are a lot more complex, but worth mulling over nonetheless.
Nitrohaulic said:
I've watched slo mo videos in which the shake appears to be from side to side. Frank Hawley has also written that tire shake happens if the tires hook up too early in a run, and that the way to avoid tire shake is to apply more power and keep the tires slipping longer.
I met Brendan Murray at a nostalgia race here in the states and he swears that he's ran the same 9" Ford STREET gear in his blown nitro front engine dragster for two years. He says that he gets away it because of the car's narrow tires and a soft clutch setting. When I told him that I was putting together a nostalgia nitro funny (which has to have big tires to fill the wells or it'd look ridiculous), he said to run a pro gear and check it often because we'll be hammering the gear with shake occasionally.
Here's what I believe is most likely. I think shake happens if ONE tire hooks up too soon. Watch how many degrees a wheel can rotate within the sidewalls at launch on super slo mo before the car even starts to move. If one slick hooks up, that wheel is going to wind that sidewall up tight the same way. Meanwhile, the other tire is still spinning, but they're both connected via the same live axle. I think that just before the one tire snaps loose again after the sidewall windup, the other tire now decides to stick (probably because it might have slowed down a bit as the other sidewall gets tight). From there I think it's just a series of both tires taking turns hooking on their own and letting go. I can't think of anything else that makes sense.
I think that applying more power and keeping them slipping longer gives them a chance to more gradually even themselves up before sticking.
www.break.com/index/drag_racing_filmed_at_1000fps.html
I've downloaded this next vid to my pc, then played the already super slo mo launch at half speed on Windows Media Player. If you do the same you'll see some amazing things. Watch how the sidewalls wind up, then the tires "snap" loose one time before tightening up AGAIN. Then the tires start slipping (apparently not gripping and snapping like the first time due to the wheel having some momentum now?)and the car begins to move forward. Look at how much the outside diameter of the tire reduces as the sidewalls wrap up before the tread snaps loose. A lot of dynamics there to try to wrap your brain around.
www.whoisthemonkey.com/videos/dragstercrashcompilation.wmv
I met Brendan Murray at a nostalgia race here in the states and he swears that he's ran the same 9" Ford STREET gear in his blown nitro front engine dragster for two years. He says that he gets away it because of the car's narrow tires and a soft clutch setting. When I told him that I was putting together a nostalgia nitro funny (which has to have big tires to fill the wells or it'd look ridiculous), he said to run a pro gear and check it often because we'll be hammering the gear with shake occasionally.
Here's what I believe is most likely. I think shake happens if ONE tire hooks up too soon. Watch how many degrees a wheel can rotate within the sidewalls at launch on super slo mo before the car even starts to move. If one slick hooks up, that wheel is going to wind that sidewall up tight the same way. Meanwhile, the other tire is still spinning, but they're both connected via the same live axle. I think that just before the one tire snaps loose again after the sidewall windup, the other tire now decides to stick (probably because it might have slowed down a bit as the other sidewall gets tight). From there I think it's just a series of both tires taking turns hooking on their own and letting go. I can't think of anything else that makes sense.
I think that applying more power and keeping them slipping longer gives them a chance to more gradually even themselves up before sticking.
www.break.com/index/drag_racing_filmed_at_1000fps.html
I've downloaded this next vid to my pc, then played the already super slo mo launch at half speed on Windows Media Player. If you do the same you'll see some amazing things. Watch how the sidewalls wind up, then the tires "snap" loose one time before tightening up AGAIN. Then the tires start slipping (apparently not gripping and snapping like the first time due to the wheel having some momentum now?)and the car begins to move forward. Look at how much the outside diameter of the tire reduces as the sidewalls wrap up before the tread snaps loose. A lot of dynamics there to try to wrap your brain around.
www.whoisthemonkey.com/videos/dragstercrashcompilation.wmv
Edited by Nitrohaulic on Friday 24th November 02:01
Welcome Ron!
This man is gonna have a bitchin' Nostalgia FC!
Thanks for the welcome (and letting me know about this site). How many Dragsterworld people are here? Hated to see that site go. Was a great place to be.
Yeah, I remember people using connected air lines to try to air both tires up exactly evenly. When watching how much the outside diameter of the tires change as the sidewall wraps up and draws the tread closer, I think it throws anything related to closer tolerances right out the window.
That's another dynamic to think about, too. If one tire/tyre (LOL, little cultural correctness for ya!) hooks first, look at how much the diameter is going to shrink while the other tire is still spinning. If the other tire hooks before the first one lets go, now you've got a big tire and a small tire. Now they're also going to exchange sizes as one shrinks as it tightens and the other grows when it snaps loose. A LOT of things going on there to think about. I think it's amazing what they're able to do with two big balloons as it is. I think it's crazy to EXPECT to be able to make them both hook at exactly the same point. Downtrack they probably just do it a little closer to each other. I'll bet that the longer they slip and the more gradually they both slow down to hook, the more they even themselves out. If they hook too soon, one may be too far behind the other.
I'd have to search, but I remember that someone in the Southern California area did tests on a fueler years ago with some huge diameter rims and tires with short, stiff sidewalls. You gotta wonder if this problem is one that they were trying to solve.
I'll bet it's a net thing. I think there's good and bad in everything and in order to get the benefits of the loose sidewalls you have to take the disadvantages that come with them. It does tell you that there's still room for improvement (as long as NHRA doesn't KNOW you're trying to improve anything, LOL. Can't have that.)
I'm just a 41 year old who's passionately loved funny cars since seeing them for the first time on TV at about the age of five. Like a lot of people, I was just convinced that that was what I was going to do someday. Like a lot of people, I watched them make themselves more expensive from the late 70s/early 80s on faster than I could ever start to make money.
Now the nostalgia thing is opening up some opportunities for a lot of us. Like Virgil Hartman emphasizes the word on classicfunnycarboard, I believe the key is in the SHOW at small tracks instead of RACING at big tracks. I believe that blown nitro running at small tracks will grow to be a bigger show than it even was in the 70s. NASCAR's been popular for about 20 years and they've built d*mn choppers just about every way I think you could build one. I think the public is more than ready for this. When I was a kid I remember seeing a funny car in someone's driveway once. I want to see a LOT of funny cars in a LOT of driveways someday. That's just right.
Yeah, I remember people using connected air lines to try to air both tires up exactly evenly. When watching how much the outside diameter of the tires change as the sidewall wraps up and draws the tread closer, I think it throws anything related to closer tolerances right out the window.
That's another dynamic to think about, too. If one tire/tyre (LOL, little cultural correctness for ya!) hooks first, look at how much the diameter is going to shrink while the other tire is still spinning. If the other tire hooks before the first one lets go, now you've got a big tire and a small tire. Now they're also going to exchange sizes as one shrinks as it tightens and the other grows when it snaps loose. A LOT of things going on there to think about. I think it's amazing what they're able to do with two big balloons as it is. I think it's crazy to EXPECT to be able to make them both hook at exactly the same point. Downtrack they probably just do it a little closer to each other. I'll bet that the longer they slip and the more gradually they both slow down to hook, the more they even themselves out. If they hook too soon, one may be too far behind the other.
I'd have to search, but I remember that someone in the Southern California area did tests on a fueler years ago with some huge diameter rims and tires with short, stiff sidewalls. You gotta wonder if this problem is one that they were trying to solve.
I'll bet it's a net thing. I think there's good and bad in everything and in order to get the benefits of the loose sidewalls you have to take the disadvantages that come with them. It does tell you that there's still room for improvement (as long as NHRA doesn't KNOW you're trying to improve anything, LOL. Can't have that.)
I'm just a 41 year old who's passionately loved funny cars since seeing them for the first time on TV at about the age of five. Like a lot of people, I was just convinced that that was what I was going to do someday. Like a lot of people, I watched them make themselves more expensive from the late 70s/early 80s on faster than I could ever start to make money.
Now the nostalgia thing is opening up some opportunities for a lot of us. Like Virgil Hartman emphasizes the word on classicfunnycarboard, I believe the key is in the SHOW at small tracks instead of RACING at big tracks. I believe that blown nitro running at small tracks will grow to be a bigger show than it even was in the 70s. NASCAR's been popular for about 20 years and they've built d*mn choppers just about every way I think you could build one. I think the public is more than ready for this. When I was a kid I remember seeing a funny car in someone's driveway once. I want to see a LOT of funny cars in a LOT of driveways someday. That's just right.
Edited by Nitrohaulic on Friday 24th November 13:38
I gotta find one of those free pic posting sites. I'm still a self-taught computer idiot! The only pic I've got of the 80 Omni body is an old scanned handout from when my friend, Gary Litton, campaigned it as the Tennessee Shaker a little over twenty years ago. I bought the body twenty years ago (for $250) right after he got sponsorship to run identical nitro funny cars for he and his son. Gary's the one who told me back then "We match race at small tracks all year to make money, then enter one or two national events a year to spend money." He had a 14-71 engine to race with and a 10-71 KB blocked, iron headed engine to put on shows with.
The only pics I've got of the chassis are from where it was sitting in the former owner's driveway in Texas. Someone half converted it to a bracket altered already by the time I got it. I've still got to call a lady at SEMA with the tag number to see who built it, but the torsion bar front end looks exactly like Donnie Reeves' Mustang (down to the scallops on the ends of the links), which is a Buttera. If there's a way for me to post them here, just tell me how and I'll do it.
As far as parts, I've scored a Lencodrive (a big investement even at $6,500 used, but no clutch to maintain), a Rodeck block ($1,500), a set of new in the box BME rods ($500 with a $1,300 invoice), an anodized and stripped 6-71 Mooneyham ($935), new top fuel Goodyears that were too big for someone else's car ($750), and a pair of 16x14 Weld Draglites last week for $375. A guy's holding a new billet 3.75 stroke crank for me for $1,400 as soon as I get saved up again. The chassis came with headers. If it weren't for getting deals on e-bay and other sites this thing would go nowhere!
I'm just someone who's always had a lot more love for the sport than ability to do anything in it (Like that doesn't describe most of us!).
The only pics I've got of the chassis are from where it was sitting in the former owner's driveway in Texas. Someone half converted it to a bracket altered already by the time I got it. I've still got to call a lady at SEMA with the tag number to see who built it, but the torsion bar front end looks exactly like Donnie Reeves' Mustang (down to the scallops on the ends of the links), which is a Buttera. If there's a way for me to post them here, just tell me how and I'll do it.
As far as parts, I've scored a Lencodrive (a big investement even at $6,500 used, but no clutch to maintain), a Rodeck block ($1,500), a set of new in the box BME rods ($500 with a $1,300 invoice), an anodized and stripped 6-71 Mooneyham ($935), new top fuel Goodyears that were too big for someone else's car ($750), and a pair of 16x14 Weld Draglites last week for $375. A guy's holding a new billet 3.75 stroke crank for me for $1,400 as soon as I get saved up again. The chassis came with headers. If it weren't for getting deals on e-bay and other sites this thing would go nowhere!
I'm just someone who's always had a lot more love for the sport than ability to do anything in it (Like that doesn't describe most of us!).
Edited by Nitrohaulic on Sunday 26th November 01:18
[URL=http://imageshack.us]
[/URL]
[URL=http://imageshack.us]
[/URL]
[URL=http://imageshack.us]
[/URL]
Heres Rons car!
Send me the pic of the body if you want me to upload it!
Dan
[/URL] [URL=http://imageshack.us]
[/URL] [URL=http://imageshack.us]
[/URL] Heres Rons car!
Send me the pic of the body if you want me to upload it!
Dan
Edited by flying toilet on Friday 24th November 16:20
Edited by flying toilet on Friday 24th November 16:21
Heres an update of Rons car. He sent me this scan of a handout of the car in its old guise!
The new paint is going incorporate his username.
[URL=http://imageshack.us]
[/URL]
The new paint is going incorporate his username.
[URL=http://imageshack.us]
[/URL] Edited by flying toilet on Wednesday 29th November 14:08
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