The Spool Shimmy
07-08-2008, 12:34 PM
#16
this has been a very interesting thread, though i am still very interested in sosidge's original question - any suggestions on how to smooth out the "shimmy" on asphalt?
bueller?
bueller?
07-09-2008, 02:04 AM
#18
I guess it depends on your driving style, some people like a twitchy feel to their car, others prefer a more "lazier" feel, where the chassis isnt so responsive.
07-09-2008, 02:41 AM
#19
Just as a goof, I tried running a tightened ball diff in the front and a loose in the rear about a couple years ago. I noticed the tail wag on launch and I liked it so much I decided to keep it as a carpet setup.
During the winter while I was TQ'ing, the track boss came up to me and pointed out that I had the fastest laptime of all the people there. I looked over to see if he was pulling my leg and sure enough, I was quicker than the pack by a quarter of a second.
oneways just feel 'wierd' to me. the car takes on such a different characteristic that I tend to think about how to drive the car than running the track fast.
as for this question: "any suggestions on how to smooth out the "shimmy" on asphalt?"
I would try a softer rear end with a little more camber.
During the winter while I was TQ'ing, the track boss came up to me and pointed out that I had the fastest laptime of all the people there. I looked over to see if he was pulling my leg and sure enough, I was quicker than the pack by a quarter of a second.
oneways just feel 'wierd' to me. the car takes on such a different characteristic that I tend to think about how to drive the car than running the track fast.
as for this question: "any suggestions on how to smooth out the "shimmy" on asphalt?"
I would try a softer rear end with a little more camber.
07-09-2008, 11:14 AM
#20
That would give the car more steering on the exit of the corner, this could make the car twitchy and harder to drive, but then again it might help you control the car better.
I guess it depends on your driving style, some people like a twitchy feel to their car, others prefer a more "lazier" feel, where the chassis isnt so responsive.
I guess it depends on your driving style, some people like a twitchy feel to their car, others prefer a more "lazier" feel, where the chassis isnt so responsive.
Surely this is on power and such will generate rear grip and less steering
07-09-2008, 12:20 PM
#21
In fact the opposite is true, more INCREASES grip.
More front droop means the inside wheel is less likely to lift off the ground and become unloaded on power, so that way you get smoother, more consistent steering all the way through the bend.
It wouldn't be the first change I made to get more steering on-power, but it does have an effect.
In terms of the spool shimmy I don't see why more front droop would help either but if it works for others it may be worth a try. My impression from other peoples responses to my original question is that you either "deal with it" or fit a different front drive. Which suits me as I have a spool, diff and one-way in the pit box to choose from!
07-09-2008, 02:41 PM
#22
not sure I can agree on the steering thing still. I do agree it makes it smoother but not increased. More droop will generate more grip by allowing chassis roll and on bumpy tracks it allows the car to stay flatter and not skit over the surface.
Back on the spool shimmy I found that a slightly looser rear belt seemed to help as It caused a small delay between acceleration and actual drive so it has less snatch in the drive train.
Back on the spool shimmy I found that a slightly looser rear belt seemed to help as It caused a small delay between acceleration and actual drive so it has less snatch in the drive train.
07-09-2008, 03:11 PM
#23
Loads of people misunderstand droop and think that more decreases grip.
In fact the opposite is true, more INCREASES grip.
More front droop means the inside wheel is less likely to lift off the ground and become unloaded on power, so that way you get smoother, more consistent steering all the way through the bend.
It wouldn't be the first change I made to get more steering on-power, but it does have an effect.
In terms of the spool shimmy I don't see why more front droop would help either but if it works for others it may be worth a try. My impression from other peoples responses to my original question is that you either "deal with it" or fit a different front drive. Which suits me as I have a spool, diff and one-way in the pit box to choose from!
In fact the opposite is true, more INCREASES grip.
More front droop means the inside wheel is less likely to lift off the ground and become unloaded on power, so that way you get smoother, more consistent steering all the way through the bend.
It wouldn't be the first change I made to get more steering on-power, but it does have an effect.
In terms of the spool shimmy I don't see why more front droop would help either but if it works for others it may be worth a try. My impression from other peoples responses to my original question is that you either "deal with it" or fit a different front drive. Which suits me as I have a spool, diff and one-way in the pit box to choose from!
stu rand
2007/2008 carpet wars chanpion
2007 corally stcc champion
07-09-2008, 03:13 PM
#24
Loads of people misunderstand droop and think that more decreases grip.
In fact the opposite is true, more INCREASES grip.
More front droop means the inside wheel is less likely to lift off the ground and become unloaded on power, so that way you get smoother, more consistent steering all the way through the bend.
It wouldn't be the first change I made to get more steering on-power, but it does have an effect.
In terms of the spool shimmy I don't see why more front droop would help either but if it works for others it may be worth a try. My impression from other peoples responses to my original question is that you either "deal with it" or fit a different front drive. Which suits me as I have a spool, diff and one-way in the pit box to choose from!
In fact the opposite is true, more INCREASES grip.
More front droop means the inside wheel is less likely to lift off the ground and become unloaded on power, so that way you get smoother, more consistent steering all the way through the bend.
It wouldn't be the first change I made to get more steering on-power, but it does have an effect.
In terms of the spool shimmy I don't see why more front droop would help either but if it works for others it may be worth a try. My impression from other peoples responses to my original question is that you either "deal with it" or fit a different front drive. Which suits me as I have a spool, diff and one-way in the pit box to choose from!
07-09-2008, 03:30 PM
#25
Ok people, please be patient with me since it's been a long time since I ran anything electric or on carpet but the thread caught my eye since spools are making a comeback on nitro TC's. Actually I want to talk about front droop though.
With dirt oval cars, more front droop reduces on power steering off the corner. I believe there are two reasons for this. 1. We run so much droop the nose really comes up and transfers weight to the rear tires. 2. when the nose rises it reduces downforce on the nose of the car. I use dirt oval cars for my example because of the extreme amount of droop we sometimes run so you can really feel and see this effect.
I find droop has the exact same effect on nitro on road cars on asphalt.
I suspect that if you had very little droop and a stiffer front suspension that the opposite effect could happen. Increasing droop might then increase on power steering.
Perhaps carpet TC's are different but that is what I have noticed.
With dirt oval cars, more front droop reduces on power steering off the corner. I believe there are two reasons for this. 1. We run so much droop the nose really comes up and transfers weight to the rear tires. 2. when the nose rises it reduces downforce on the nose of the car. I use dirt oval cars for my example because of the extreme amount of droop we sometimes run so you can really feel and see this effect.
I find droop has the exact same effect on nitro on road cars on asphalt.
I suspect that if you had very little droop and a stiffer front suspension that the opposite effect could happen. Increasing droop might then increase on power steering.
Perhaps carpet TC's are different but that is what I have noticed.
07-09-2008, 03:31 PM
#26
Hi Guys
Just from reading this thread i was wondering if the shimmy isnt the result of the unloaded inside front wheel finally biting as the car settles back into its suspension. This would cause a brief dart to the outside of the corner.
Therefore the answer would be more fr droop to stop the wheel lifing quite so much=less slip.
Just from reading this thread i was wondering if the shimmy isnt the result of the unloaded inside front wheel finally biting as the car settles back into its suspension. This would cause a brief dart to the outside of the corner.
Therefore the answer would be more fr droop to stop the wheel lifing quite so much=less slip.
07-09-2008, 03:57 PM
#27
It all depends on what you define "droop" as. if your thinking of "more droop" as a bigger number on a downstop gauge such as the ASC. one or the one in the hudy setup then you will get more on power steering. if "more droop" is more chassis travel before the chassis hits the downstops (meaning a smaller # on a downstop gauge) then it will reduce on power steering, and is possibly a solution to the original poster's question. personally, i would check chassis tweak and balance, and see if that is not the cause of the car doing this.
07-09-2008, 04:00 PM
#28
I can't believe I forgot to mention that. When I refer to droop I mean how far up the chassis can be lifted before hitting the stops. There are still a lot of people out there that go by Serpent terminology where they refer to a bigger number on the gauge as more droop.
Last edited by wingracer; 07-09-2008 at 05:44 PM.
07-09-2008, 05:04 PM
#29
nah im with tim on this one if you give the front more droop it wil affect give more steering though the corner (no throttle input)but under hard acceleration when the spool shimmy comes in it will not give you more steering as more weight can be transferd to the rear thus giving the rear more traction so if the rear has more traction the car cannot have more steering
stu rand
2007/2008 carpet wars chanpion
2007 corally stcc champion
stu rand
2007/2008 carpet wars chanpion
2007 corally stcc champion