If you talked to Randal he will be the first to tell you he was having trouble with the feel of the power brakes on Bill's car.
I was just reviewing the video again and although Bill was faster overall, he was throwing the car into the corners. Literally. His rear wheels were coming off the ground and bouncing.
You were actually smoothing out nicely at the end of your runs. Best times for you too.
Other side went up, too.
KT
Full Version: wheel lift ... what to do about it?
QUOTE(trekkor @ May 17 2006, 08:26 PM) 
Other side went up, too.
i can't help it, i'm a pinky-lifter ...
AndyPS: how about emailing me that video?
QUOTE(Dave_Darling @ May 17 2006, 05:02 PM)
QUOTE(Brett W @ May 17 2006, 04:25 PM)
A car will always corner faster on four wheels than it will on three.
When you have to compromise the grip elsewhere just to get the one tire to touch down, the car will corner slower on four wheels than three. Sure you can add a ton of rear roll stiffness to get that front tire down, but then the car will oversteer, probably pretty badly!James (Lapuwali) is dead-on correct in this.
--DD
I was going to say roughly the same thing as Dave - I have a race car suspension book somewhere that states carrying one front tire through a corner isn't a bad thing. The author made a point to refer to road holding and handling as two separate things - the cars front tire has a road holding of zero, but the handling may be the best it can be. He also made mention of putting the tire over the inside berm to cut the corner better since it was already floating that high - but more as a point of humor.
There was a thread on the bird board about this same question awhile back - the guy had a 911 and was concerned it carried the front tire through corners. In the Autocross forum.
QUOTE(byndbad914 @ May 17 2006, 08:58 PM)
the cars front tire has a road holding of zero
i don't see how this could be true ... yes, you're unloading that side of the car, so there will be more weight on the other side for sure, but there has to be a difference between 3 x 9" slicks on the ground as opposed to 4 x 9" slicks on the ground. even if the 4th one has less weight on it, i can't see how that tire would not have any impact on the overall "stickyness" ...
Andy
i think you stated that this lift is comming thru a series of connected turns, right?
what shocks are you using?
if there adjustable, soften them [front] up a little. you might be jacking the suspension by the shocks being to stiff and there not being enough time or force for them to react.
or stiffen the rear shocks up some.
what shocks are you using?
if there adjustable, soften them [front] up a little. you might be jacking the suspension by the shocks being to stiff and there not being enough time or force for them to react.
or stiffen the rear shocks up some.
but then again it just might be the "tweak" in the tub causing you this pain.
Hi Andy,
I've been talking with several people about the two wheels up issue on our cars and the unanimous conclusion from the race car prep shops is that the cars are too soft. But is is not an easy fix soft. The roll center of our cars are too high for the amount of traction that the slicks are generating. I showed JWE your vid and mine, in fact Rich and the boys were already looking at it when I called. I also called Hoosier and Goodyear and talked with their techs. In the case of Goodyear, I got to speak to one of their engineers.
Andy, in your case, since it's a street car you will need to compromise. You either change the setup or go slower. In this case you would stiffen the rear springs while adjusting the oversteer out by tightening the front bar. You would also benefit from lowering the car. Since you have a bent tub and don't want to stiffen the car, you're effectively hosed. The tire engineers did say that if we are catching the tires on pavement because they are sticking and / or rolling over (like mine did by almost 2 inches) on the sidewall, we need to up the tire pressure. This will strengthen the sidewall and in the event of transfer load at an AX, the tire should skate instead of biting. This should keep at least 3 wheels down.
In my case, we already knew that the roll center was too high. We left the springs and ride height as I purchased the car to do exactly what we are doing, play with the setup to suit my driving ability and style. The car is now back at JWE for some adjustments, most likely a spring rate increase and lowering the car another 1.5 inches to lower the center of gravity. I'm also putting in a remote fuel tank to help with my fuel starvation I have been experiencing on the big tracks.
Trekkor also points out that Randal is much smoother than we are and there's no arguing that I'm not. So smoothness may reward the setup if the car is setup for smoothness. My style on the big tracks has gotten much smoother, but AXing is still a learing curve for me. In think Trekkor has something like 30 AX's under his belt and Randal has probably 2 or 3 times that. They are much more experienced than I am. You and I are still relatively newbies, or at least I am as this last AX was my 22nd time. I only ran a full schedule for 2003 before blowing up at the beginning of 2004 and I just got back to it this year.
And yes Andy, Randal and I DESTROYED the set of slicks on the car! The fronts are shredded and the rears may have another AX in them!
So, if you don't want to stiffen her up, pump up them tires and make here skate!
Bill P.
I've been talking with several people about the two wheels up issue on our cars and the unanimous conclusion from the race car prep shops is that the cars are too soft. But is is not an easy fix soft. The roll center of our cars are too high for the amount of traction that the slicks are generating. I showed JWE your vid and mine, in fact Rich and the boys were already looking at it when I called. I also called Hoosier and Goodyear and talked with their techs. In the case of Goodyear, I got to speak to one of their engineers.
Andy, in your case, since it's a street car you will need to compromise. You either change the setup or go slower. In this case you would stiffen the rear springs while adjusting the oversteer out by tightening the front bar. You would also benefit from lowering the car. Since you have a bent tub and don't want to stiffen the car, you're effectively hosed. The tire engineers did say that if we are catching the tires on pavement because they are sticking and / or rolling over (like mine did by almost 2 inches) on the sidewall, we need to up the tire pressure. This will strengthen the sidewall and in the event of transfer load at an AX, the tire should skate instead of biting. This should keep at least 3 wheels down.
In my case, we already knew that the roll center was too high. We left the springs and ride height as I purchased the car to do exactly what we are doing, play with the setup to suit my driving ability and style. The car is now back at JWE for some adjustments, most likely a spring rate increase and lowering the car another 1.5 inches to lower the center of gravity. I'm also putting in a remote fuel tank to help with my fuel starvation I have been experiencing on the big tracks.
Trekkor also points out that Randal is much smoother than we are and there's no arguing that I'm not. So smoothness may reward the setup if the car is setup for smoothness. My style on the big tracks has gotten much smoother, but AXing is still a learing curve for me. In think Trekkor has something like 30 AX's under his belt and Randal has probably 2 or 3 times that. They are much more experienced than I am. You and I are still relatively newbies, or at least I am as this last AX was my 22nd time. I only ran a full schedule for 2003 before blowing up at the beginning of 2004 and I just got back to it this year.
And yes Andy, Randal and I DESTROYED the set of slicks on the car! The fronts are shredded and the rears may have another AX in them!
So, if you don't want to stiffen her up, pump up them tires and make here skate!
Bill P.
Lower the car.
I have spent a lot of time around the Bias Ply (E-prod and F-prod SCCA 914's).
These tires are the reason we cut the inner mounts and raised the rear suspension pick up points (to get a better CG) The tires worked MUCH better.
What kind of pressure where you guy's running?
B
I have spent a lot of time around the Bias Ply (E-prod and F-prod SCCA 914's).
These tires are the reason we cut the inner mounts and raised the rear suspension pick up points (to get a better CG) The tires worked MUCH better.
What kind of pressure where you guy's running?
B
Nice, Bill... 
KT
KT
I'm betting Andy's front shocks are completely shot. Nevermind the stock Carrera bushings in the arms.
B
B
Corner weights are dynamic. Traction is a function of downward force on the tire, as well as it's inherent "stickyness". A lifted tire obviously has zero downforce on it (and therefore generates zero traction), but even a tire that remains on the ground may have very little downforce on it, perhaps so little that the contribution to overall traction is still unmeasurable. At best, the contribution of the inside front will be small relative to the most heavily loaded outside tire (which appears to be the outside rear on your car).
In any turn you're going to have SOME weight transfer from the inside tires to the outside tires, so the outside tires will have more downforce, and thus will be contributing more to the overall traction than the inside tires. At the extreme, you lift the inside tires completely off the ground. There is no way to eliminate weight transfer, and anything you do to reduce it will increase body roll, except lowering the car's center of gravity, which obviously is limited by ground clearance. Therefore, the percentage of traction the inside tires produce will always be less than the outside tires.
It's possible that your car can have good handling balance and have all four wheels on the ground. My point is that you shouldn't automatically assume that lifting a wheel is bad. The difference in overall traction between a lifted tire and one barely kissing the pavement will be small. I strongly suspect that without fairly serious changes (one of which would be serious lowering) to your car's setup, that you're not going to do much more than have the inside front very lightly loaded, and thus only generating a tiny amount of additional traction.
In any turn you're going to have SOME weight transfer from the inside tires to the outside tires, so the outside tires will have more downforce, and thus will be contributing more to the overall traction than the inside tires. At the extreme, you lift the inside tires completely off the ground. There is no way to eliminate weight transfer, and anything you do to reduce it will increase body roll, except lowering the car's center of gravity, which obviously is limited by ground clearance. Therefore, the percentage of traction the inside tires produce will always be less than the outside tires.
It's possible that your car can have good handling balance and have all four wheels on the ground. My point is that you shouldn't automatically assume that lifting a wheel is bad. The difference in overall traction between a lifted tire and one barely kissing the pavement will be small. I strongly suspect that without fairly serious changes (one of which would be serious lowering) to your car's setup, that you're not going to do much more than have the inside front very lightly loaded, and thus only generating a tiny amount of additional traction.
QUOTE(Brad Roberts @ May 17 2006, 09:42 PM)
What kind of pressure where you guy's running?
21 cold in the front, 22 cold in the rear ...
didn't gain much in the morning (~3lbs) which i bled off after the first afternoon run ...
coincidentally, that very next run i was on two wheels ...
Andy
Are these the R430's?
We start the 430's around 19 or so for road racing.
Sounds like you are going to need 31/32 hot.
B
We start the 430's around 19 or so for road racing.
Sounds like you are going to need 31/32 hot.
B
QUOTE(nine14cats @ May 17 2006, 09:35 PM)
... you're effectively hosed ...
yeah, once the thing is straight, i will drop it a few inches. that should help.
also got the mueller roller bearings and new trailing arms. maybe some stiffer torsion bars.
i guess a set of koni's wouldn't hurt either ...
that should make a difference ...
Andy
Hi B,
On the slicks Andy has on his car, I was running ~24lbs hot front and 25lbs hot rear (on our 914-6). I would experience rollover on the sidewall at anything less than that. But I was running ~400lbs springs in the back, and the car was slammed, so I wasn't getting the body roll that Andy is getting. As a datapoint, the 2 wheel up I had at Marina in 2003 was with 250lbs springs in the back.....same as what Andy has now.
On the 911 we were running 23 hot and 25 hot front/back at the end of the day. Goodyear believes I need to up it to 27 or 28 hot....they say with the rear engine the rear tires will stay plenty warm.
Bill P.
On the slicks Andy has on his car, I was running ~24lbs hot front and 25lbs hot rear (on our 914-6). I would experience rollover on the sidewall at anything less than that. But I was running ~400lbs springs in the back, and the car was slammed, so I wasn't getting the body roll that Andy is getting. As a datapoint, the 2 wheel up I had at Marina in 2003 was with 250lbs springs in the back.....same as what Andy has now.
On the 911 we were running 23 hot and 25 hot front/back at the end of the day. Goodyear believes I need to up it to 27 or 28 hot....they say with the rear engine the rear tires will stay plenty warm.
Bill P.
QUOTE(Brad Roberts @ May 17 2006, 10:23 PM)
Are these the R430's?
Sounds like you are going to need 31/32 hot.
R250 (the softest out there for 15x7) ... 32 hot will have me sliding all over the place ...
i used to run them 16 cold before the corner balance ...
Andy
I like what James is saying. Shouldn't you only be trying to cure front wheel lift if you're experiencing understeer? If you're not understeering, that seems to tell me that you have enough traction for the corner at the speed your taking it.
I'm with Brad. There seem like a lot of assumptions about your front suspension. IIRC, the life of your shocks is unknown and the torsion bars have never been measured. Next time you're at the shop, lets pull out a torsion bar and measure it.
I'm with Brad. There seem like a lot of assumptions about your front suspension. IIRC, the life of your shocks is unknown and the torsion bars have never been measured. Next time you're at the shop, lets pull out a torsion bar and measure it.
QUOTE(nine14cats @ May 17 2006, 10:25 PM)
the 2 wheel up I had at Marina in 2003 was with 250lbs springs in the back.....
wasn't that in reno ???
Andy
Jesus. How old are these 230's? I thought they stopped making them back in 03 or something. Yep. 31/32 is too hot for a 230.
Bill,
great point about the rear engine and heating the tires.
Hum.. maybe I should try some 430's on the Boxster. That would be BITCHIN.
B
Bill,
great point about the rear engine and heating the tires.
Hum.. maybe I should try some 430's on the Boxster. That would be BITCHIN.
B
QUOTE(McMark @ May 17 2006, 10:29 PM)
Next time you're at the shop, lets pull out a torsion bar and measure it.
AndyQUOTE(Brad Roberts @ May 17 2006, 10:30 PM)
Jesus. How old are these 230's? I thought they stopped making them back in 03 or something. Yep. 31/32 is too hot for a 230.
250 (two fif ty) ... goddyear still sells them in 15 x 9" ... my set is old tho, i got it used from bill ... yet the rubber is still very soft and once warm sticks like glue ... they have a few more AX in them ...
![shocked[1].gif](http://www.914world.com/bbs2/style_emoticons/default/shocked[1].gif)
Andy
Andy,
You had me confused earlier. I would have thought that with the 250# coils and big ol' 23 mmm sway bar that you were running equally beefy torsion bars. Stock 911 bars are still pretty whimpy (19 mm). You could easilly be overloading those torsion bars. Hit the stop and your roll center instantly transfers from the center of the car to the contact patch of the outside tire. That'll pull your inside wheel (and fender) pretty high off the ground, and it can be rather abrupt too.
Beef up the front suspension pronto. You should be able to go to 21 mm or 22 mm torsion bars and loose the rear sway bar. Elimiation of the rear sway bar will also help prevent the wheelspin you were describing as well. Running that much spring with a rear bar on slicks is a sure fire recipie for wheelspin. And a mongo sway bar with small torsion bars will definitely get that inside wheel airborne.
Beefy torsion bars will resist the compression that the sway bar is coupling to the inboard suspension.
-Josh2
You had me confused earlier. I would have thought that with the 250# coils and big ol' 23 mmm sway bar that you were running equally beefy torsion bars. Stock 911 bars are still pretty whimpy (19 mm). You could easilly be overloading those torsion bars. Hit the stop and your roll center instantly transfers from the center of the car to the contact patch of the outside tire. That'll pull your inside wheel (and fender) pretty high off the ground, and it can be rather abrupt too.
Beef up the front suspension pronto. You should be able to go to 21 mm or 22 mm torsion bars and loose the rear sway bar. Elimiation of the rear sway bar will also help prevent the wheelspin you were describing as well. Running that much spring with a rear bar on slicks is a sure fire recipie for wheelspin. And a mongo sway bar with small torsion bars will definitely get that inside wheel airborne.
Beefy torsion bars will resist the compression that the sway bar is coupling to the inboard suspension.
-Josh2
I'm running 250 compound for AX (my set is toast now, I may just use one of the heat cycled sets for now) and I'm running R600 GY's for the GTL spec set up. I'm also tire testing my favorites -- Hoosier slicks in the R45A and R55 compound. It appears based on lamp times and stickiness (butt dyno) that going from sticky to least sticky it looks like this:
Goodyear R250
Hoosier R45A
Hoosier R55
Goodyear R430
Goodyear R600
But.....the Goodyear R250's kick ass at AX and the R600's are just wearing and heat cycling great. The R600 fall off is gradual and I'm still waiting for the dead point.
I prefer the feel of Hoosiers....which is odd since they have a softer sidewall...but I do.
I thing R430's on the Boxster would be great!
Bill P.
Goodyear R250
Hoosier R45A
Hoosier R55
Goodyear R430
Goodyear R600
But.....the Goodyear R250's kick ass at AX and the R600's are just wearing and heat cycling great. The R600 fall off is gradual and I'm still waiting for the dead point.
I prefer the feel of Hoosiers....which is odd since they have a softer sidewall...but I do.
I thing R430's on the Boxster would be great!
Bill P.
one more of trekkors videos, covers the last 3rd of the AX course this sat.
i counted 5 (five) times in just that section where i could clearly see a front wheel off the ground ...
Andy
http://www.914world.com/videos/Cap0023.wmv (2 MB)
i counted 5 (five) times in just that section where i could clearly see a front wheel off the ground ...
Andyhttp://www.914world.com/videos/Cap0023.wmv (2 MB)
Rear end seamed to bounce at the end..
how old are your rear shocks?
I wana play!!!!
alls I got is lousy R tires... I need some slicks... arg
how old are your rear shocks?
I wana play!!!!
alls I got is lousy R tires... I need some slicks... arg
You guys may find it OK to settle for the suggestion that is is not important to worry about it, but I see it the exact opposite. If this is your street car then deal with the compromises inherent in that system.
If you want a car that is the best, then do what ever it takes to settle this problem. Either take some stiffness out of the front or add some to the rear. I would start with 50lbs and see what happens.
Roll stiffness is not just added through sway bars, add spring.
This car really needs a baseline, before you can go anywhere.
If you want a car that is the best, then do what ever it takes to settle this problem. Either take some stiffness out of the front or add some to the rear. I would start with 50lbs and see what happens.
Roll stiffness is not just added through sway bars, add spring.
This car really needs a baseline, before you can go anywhere.
Come to think of it: I think his rear shocks were given to him by me (and they were old/used whe I gave them too him)
Lets get the tub straight first. Worry about the rest later.
B
Lets get the tub straight first. Worry about the rest later.
B
QUOTE(Andyrew @ May 17 2006, 11:02 PM)
Rear end seamed to bounce at the end..
yeah, i beat it into submission. trailbraking going into the corner hot to get that ass to come around while applying throttle ...
works well if there's no more track afterwards you have to worry about ...
got the right front to lift quite a bit there too ...
yeah, those are old bilsteins from brad, they seem to be working fine, i checked them when i put on the 250lbs springs ...
Andy
If you have to trail brake to get it to turn in, then I would say that you can afford to put a couple more lbs in the rear....
then again thats slow speeds... so... I dono..
then again thats slow speeds... so... I dono..
Andy,
should we attempt to straighten two tubs memorial day weekend?
Put together a club day at Yeamans? Get as many hands as possible for disassembly and re assembly of "Ole Red"??
I think Jenny's car was drivable in 18hrs.
We are a tad older.. but we can do it.
I'm in if you want to pull it off.
We will need to reserve the Cellete fixtures for that Friday.
Thoughts? I"ll start another thread when you pull the trigger.
B
should we attempt to straighten two tubs memorial day weekend?
Put together a club day at Yeamans? Get as many hands as possible for disassembly and re assembly of "Ole Red"??
I think Jenny's car was drivable in 18hrs.
We are a tad older.. but we can do it.
I'm in if you want to pull it off.
We will need to reserve the Cellete fixtures for that Friday.
Thoughts? I"ll start another thread when you pull the trigger.
B
The roll centers on a stock 914 front suspension are too low... not too high. This is why people run huge bars to counteract the large moment between the low roll center and the Cg.
I've asked this before.... How much travel does your front damper have from ride height to jounce bumper engagement? And what kind of jounce bumper are you running (height and relative stiffness)? My guess is your bottoming out the front suspension on the loaded side and then what choice does your car have? It has to lift the inside wheel or slide.
There's small wheel lift, which is generally harmless, and there's what Andy has, which isn't good... too much (and sometimes 2 wheels???? this is dangerous and needs to be fixed).
Why does everyone think roll is such a bad thing? A reasonable amount of roll is required to make a car work. Check out this pic of my car in the wet.... see the roll?
Here's another pic in the dry from last year... Again, see the roll... slight inside wheel lift, but it's not a big deal because the car is settled and not going to lift another wheel...................btw I run no rear bar, so yes, my car rolls more at the back than at the front.
I've asked this before.... How much travel does your front damper have from ride height to jounce bumper engagement? And what kind of jounce bumper are you running (height and relative stiffness)? My guess is your bottoming out the front suspension on the loaded side and then what choice does your car have? It has to lift the inside wheel or slide.
There's small wheel lift, which is generally harmless, and there's what Andy has, which isn't good... too much (and sometimes 2 wheels???? this is dangerous and needs to be fixed).
Why does everyone think roll is such a bad thing? A reasonable amount of roll is required to make a car work. Check out this pic of my car in the wet.... see the roll?
Here's another pic in the dry from last year... Again, see the roll... slight inside wheel lift, but it's not a big deal because the car is settled and not going to lift another wheel...................btw I run no rear bar, so yes, my car rolls more at the back than at the front.
Damn looking at that video my 1st question was "what kinda marshmellows is he running for shocks.
You will do well by getting some Koni Sports.
Stiffer front T-bars, and rear springs.
You got to make a choice. race car or street car.
Race car gets sticky slicks and massive suspension
street car gets at the most DOT-R tires and Koni's
You are going to kill yourself in half-assing Just my .914 cents worth.
You will do well by getting some Koni Sports.
Stiffer front T-bars, and rear springs.
You got to make a choice. race car or street car.
Race car gets sticky slicks and massive suspension
street car gets at the most DOT-R tires and Koni's
You are going to kill yourself in half-assing Just my .914 cents worth.
![popcorn[1].gif](http://www.914world.com/bbs2/style_emoticons/default/popcorn[1].gif)
just watched the vid. the rear looks really spongey.
I think Andy needs to add bigger cement blocks up front to balance the car.
Andy,
Seems there are some unknown's with regard to your front suspension, if I read the thread correctly. I would suggest first identifying your suspension components, i.e. condition of shocks, condition of bushings, T-bar rate, etc. Do you have all the specs for the rear? Point being, untill you know exactly where you are, you'll be unable to know which way to go (I know this is hugely oversimplified, but I hope you get my point). Inspect and identify everything.
I read some good recommendations. I initially too think the car should be lowered a bit, but if this is not a dedicated racer car, you may be forced into a number of compromises.
Lastly, don't look for the suspension to cure poor driving habits.....please do not take this as criticism, as every racer has fallen prey to this, myself included. Someone mentioned smoothness (or rythm, or??). It can make a significant difference in lap times that no amount of suspension adjustment can compensate for. Seat time, and well structured test sessions will help tremendously.
Andys
Seems there are some unknown's with regard to your front suspension, if I read the thread correctly. I would suggest first identifying your suspension components, i.e. condition of shocks, condition of bushings, T-bar rate, etc. Do you have all the specs for the rear? Point being, untill you know exactly where you are, you'll be unable to know which way to go (I know this is hugely oversimplified, but I hope you get my point). Inspect and identify everything.
I read some good recommendations. I initially too think the car should be lowered a bit, but if this is not a dedicated racer car, you may be forced into a number of compromises.
Lastly, don't look for the suspension to cure poor driving habits.....please do not take this as criticism, as every racer has fallen prey to this, myself included. Someone mentioned smoothness (or rythm, or??). It can make a significant difference in lap times that no amount of suspension adjustment can compensate for. Seat time, and well structured test sessions will help tremendously.
Andys
Without knowing any more than I do... lowering the car will only make the problem worse. You will not use your springs for what they are designed to do and the rate will go non-linear even sooner because you'll compress the jounce bumper sooner.... and oh, by the way your roll center will get even lower requiring even more bar to counter roll.
QUOTE(Andyrew @ May 17 2006, 11:20 PM)
If you have to trail brake to get it to turn in
the car turns in fine, with slight *oversteer* ... until you're waaaaaay too hot for a corner, in which case you will go straight through the cones.
in order to take that last corner before the finish line as fast as possible, i went into the corner waaaaaay too hot, using the brake to get the rear end to come around while applying throttle to move it forward.
the result is a very high corner speed but the tradeoff is that you will upset the car greatly, which you can see in the video.
but because this was at the finish line, i was not concerned with upsetting the car coming out of that corner ...
again, for everything else, the car has a slight *oversteer* ...
AndyQUOTE(Brad Roberts @ May 17 2006, 11:21 PM)
Thoughts? I"ll start another thread when you pull the trigger.
i'm all for it! but how are we (you) going to get the /6 tub up here? now that you don't have a trailer no more ...
Andy
QUOTE(Bleyseng @ May 18 2006, 07:10 AM)
I think Andy needs to add bigger cement blocks up front to balance the car.
Cement blocks, what are you talking about? BEER! And then more beer! LOT'S of beer! And no "light" beer, either, gotta keep that weight up, need REAL beer! Heavy beer, and lots of it!
QUOTE(andys @ May 18 2006, 09:49 AM)
please do not take this as criticism
there's certainly room for improvement on the drivers side of the equation. while i like to see myself as a smooth driver, i know i left at least 1 second if not more on that course that was not car-related ...
Andy
I have access to several other trailers down here. My trailer being gone wont stop me from coming up.
I need to call Scott and make sure it is all cool with him. He needed computer help the other day. Maybe I can swing a deal.
B
I need to call Scott and make sure it is all cool with him. He needed computer help the other day. Maybe I can swing a deal.
B
Silly rabbit, slicks are for....race cars.
Did anyone see that Radical bicycling?....I thought not.
Throw a set of slicks on any stock chassis/modified suspension sumbitch
and funny things (read ugly) can happen....particularly on a high grip surface. The closer to stock the suspension (or the more obsolete), the more thrilling things can get. Soft suspension/bad shocks/misalignment/ignoring the traction circle theory (how do you high-side a motor cycle?)/rubber in the suspension.....gud luck.
It's good for me that our venue sux, so I slide/get no heat & slide summore.
I no longer lift wheels (see sux above). If I do, it's the front....and that doan worry me a bit. The cure has been stated previously in this thread.
Did anyone see that Radical bicycling?....I thought not.
Throw a set of slicks on any stock chassis/modified suspension sumbitch
and funny things (read ugly) can happen....particularly on a high grip surface. The closer to stock the suspension (or the more obsolete), the more thrilling things can get. Soft suspension/bad shocks/misalignment/ignoring the traction circle theory (how do you high-side a motor cycle?)/rubber in the suspension.....gud luck.
It's good for me that our venue sux, so I slide/get no heat & slide summore.
I no longer lift wheels (see sux above). If I do, it's the front....and that doan worry me a bit. The cure has been stated previously in this thread.
QUOTE(J P Stein @ May 18 2006, 07:02 PM)
Silly rabbit, slicks are for....race cars.
Did anyone see that Radical bicycling?....I thought not.
Throw a set of slicks on any stock chassis/modified suspension sumbitch
and funny things (read ugly) can happen....particularly on a high grip surface. The closer to stock the suspension (or the more obsolete), the more thrilling things can get. Soft suspension/bad shocks/misalignment/ignoring the traction circle theory (how do you high-side a motor cycle?)/rubber in the suspension.....gud luck.
It's good for me that our venue sux, so I slide/get no heat & slide summore.
I no longer lift wheels (see sux above). If I do, it's the front....and that doan worry me a bit. The cure has been stated previously in this thread.
SUM bitch. I just said that same thing a few posts ago. I also have sumpin like that in my last PM.
QUOTE(groot @ May 18 2006, 04:56 AM)
Why does everyone think roll is such a bad thing? A reasonable amount of roll is required to make a car work. Check out this pic of my car in the wet.... see the roll?
Kevin,
No truer words spoken! Roll transfers weight, and it's how you manage it that makes the dynamics work in your favor.
Though a picture doesn't tell all, my initial impression is what I like to describe as your car settling into the corner, rather than riding on top of it. Did you change your roll centers?
Andys
I have video of that Radical... 
KT
KT
QUOTE
Kevin,
No truer words spoken! Roll transfers weight, and it's how you manage it that makes the dynamics work in your favor.
Though a picture doesn't tell all, my initial impression is what I like to describe as your car settling into the corner, rather than riding on top of it. Did you change your roll centers?
Andys
No truer words spoken! Roll transfers weight, and it's how you manage it that makes the dynamics work in your favor.
Though a picture doesn't tell all, my initial impression is what I like to describe as your car settling into the corner, rather than riding on top of it. Did you change your roll centers?
Andys
I did in the front... I have some things up my sleeve for the rear, but they haven't been implemented yet.
It's about suspension travel, though... and appropriate damping. It sure looks like SirAndy doesn't have any front suspension travel.
one of my co workers thinks this is the coolest thing in the world. his advice would be stiffer sway bars. I nearly whopped him up side the back of his head. Honda's I'll never get it.
This would be the gy that told be his Del Sol on sreet tires and Lambo doors CF body panels would whip my teener in a road course.
Uh he broke his car trying to get with in 6 seconds a lap.
Point is there are people here who race for real and have tons of experience. Normally when I listen to them I get faster. I listen ALOT.
This would be the gy that told be his Del Sol on sreet tires and Lambo doors CF body panels would whip my teener in a road course.
Uh he broke his car trying to get with in 6 seconds a lap.
Point is there are people here who race for real and have tons of experience. Normally when I listen to them I get faster. I listen ALOT.
QUOTE
Roll transfers weight
Right
Roll does not transfer weight. The transfer of weight CAUSES roll to happen. Forces acting on the vehicle are typically some distance away from the ROLL CENTER. The force times the distance from the ROLL CENTER is a torque. This torque usually acts through the suspension (which tries to resist the torque) and roll happens.
A vehicle without suspension will have weight transfer.
The role of the suspension is to keep the four little rubber patches in contact with the ground and to provide a more smooth ride.
QUOTE(JOHNMAN @ May 19 2006, 04:21 AM)
The force times the distance from the ROLL CENTER is a torque. This torque usually acts through the suspension (which tries to resist the torque) and roll happens.
A vehicle without suspension will have weight transfer.
The role of the suspension is to keep the four little rubber patches in contact with the ground and to provide a more smooth ride.
I believe the correct term (since we're playing this game) is moment, not torque.
Anything that turns (or accelerates in any direction) will have weight transfer, whether it has a suspension or not. The real issue is how your car and it's suspension (or lack of suspension) deals with that weight transfer.
I absolutely agree about the role of the suspension. Let's use it!!!!!
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