Cure for lightfootedness...

tsk1979 · 3rd June 2005, 10:44

Hi,
I have found that while driving at extreme speeds(150-160 range) the car gets light footed. As if it has shed 500kilos. As in the steering gets exremely light. This problem is not at all there before 140. The tyres are 155/80R13. To cure this problem are wider tyres advised or a spoiler will do the trick. Also how much impact on top speed will the spoiler have. Are there any scientificaly designed spoilers available for hatches. Most of the after market stuff i have seen are cosmetic jobs with no measuments on angle and stuff. I usually run 2-3psi above manufacturer recommendation for high speeds.

hrag · 3rd June 2005, 10:52

If you are talking about the Indica, yes. The steering does feel light at high speeds. The feeling starts around 130 - 135 kmph.

Have you tried these speeds with the recommended pressures?

hrag

tsk1979 · 3rd June 2005, 11:19

Indica does not cross 130(DLS i have). this i am talking about the Getz. At around 160 i felt as if the car had slightly lifted off. I am wondering wether the 155 width tyres are to blame or is it the aerodynamics. I am scared to drive at recommended pressures because they are the "minimum" and risk of tyre burst is high at those pressures.

drifter · 3rd June 2005, 11:33

The suspension causes this....changing the tyres wont help much in lightfootedness....but upgrade from 155s to atleast 175 for the getz...actually i didnt know the getz came with 155s. 175s will make the steering a bit heavier...which will help a little at high speeds.

Drifter

nitrous · 3rd June 2005, 11:36

yes man, the tyres are biggest culprits. try to upsize asap. atleast 175/70/R13

tsk1979 · 3rd June 2005, 11:50

The GL does! Since tyres dont help, wont a spoiler increase the downforce and help in this case. On a related note, i may be buying indigo Tdi in near future which is capable of 150kmph. Would it be useful to put in a spoiler. I have used indigo for about 1K kms, and found high speed handling to be stable at 130-140. Any other user can give me feedback regarding handling at higher speeds?

Shan2nu · 3rd June 2005, 12:08

Quote:

Since tyres dont help, wont a spoiler increase the downforce and help in this case

It will, provided you get it tested in a wind tunnel. hehe

Just fitting a spoiler without knowing the effects of it on your car can be devastating.

If your car doesn't feel comfortable at 160, then it clearly shows that it's not supposed to be driven at such speeds. Try and limit yourself to 140kmph. Thats the easiest and the safest cure i could think of.

Shan2nu

anoops · 3rd June 2005, 12:48

WOW you've hit speeds of 150-160 in your indicar???...super!!...
sorry just read the rest of the post...still these speeds are possible on a getz..pretty good eh??

Steeroid · 3rd June 2005, 12:57

Quote:

Originally Posted by tsk1979

Would it be useful to put in a spoiler. I have used indigo for about 1K kms, and found high speed handling to be stable at 130-140. Any other user can give me feedback regarding handling at higher speeds?

I'm not sure how far this is applicable to all cars, but the source is impeccable. One of my ex-colleagues is now part of the BMW Williams F1 team (a pretty junior member) after he finished his specialization in aerodynamics. According to him the spoilers on roadcars are purely decorative as the downforce becomes useable only at speeds > 200 kmph, and that too when the spoiler has been designed after windtunnel tests. SMall changes in the positioning and height makes a huge difference and could even result in the car handling badly (all this at speeds over 200 kmph).

Therefore I really doubt if adding a spoiler to an Indica or a Gets will make things better. Apparently aero skirts make more of a difference at those speeds, but you dont want to drive in india with those.

RX135 · 3rd June 2005, 13:05

@steer, at 150+, the effect may not be as drastic as 200+ speeds, but still it should be able to provide downforce to assist (or mess up) handling. Race cars would require far more downforce due to their extreme powered engines, which will not be the case with road cars. So, installing an OEM spoiler should be some help, especially for cars which oversteer.

hrag · 3rd June 2005, 14:47

Quote:

Originally Posted by anoops

WOW you've hit speeds of 150-160 in your indica???...super!!...
sorry just read the rest of the post...still these speeds are possible on a getz..pretty good eh??

Well, I've touched 150 kmph in my Indica LSi. It could have probably done more but I didn't want to risk it with stock tubed tyres.

hrag

speedsatya · 3rd June 2005, 15:22

try keepin a gunny bag or two in the boot if driving alone.
also spoilers on almost all cars simply cosmetic.

actually its only above 120kph that feather weighted sports cars do tend to lift of fthe ground .so the spoiler comes into the picture only after these speeds.thats the reason wven in some porsches the spoiler comes out only after 120kph.

about the getz,simply adding a spoiler will only increase its cd figures.as itis its too heavy to be airborne.
and if u feel its light at 160 the simple answer is "dont drive at 160".its not all meant to be driven at those speeds.a limit of 120 kph on our roads is more than enough.

3rd June 2005, 16:05

guys
i have done 175kmph in my indica petrol (lsi) of course with 175/60/13R rubbers and even at that speed the car felt rock solid .............. the car is very stable at any speed and at any condition that to with out any spoiler or anything................

tsk1979 · 3rd June 2005, 16:06

Quote:

Originally Posted by speedsatya

and if u feel its light at 160 the simple answer is "dont drive at 160".its not all meant to be driven at those speeds.a limit of 120 kph on our roads is more than enough.

hehe, point taken sir

. I too think 120-130 is the limit for expressway!

Abhay · 3rd June 2005, 17:18

I am sure the spoilers are more to do with cosmetics than downforce on these hatches although cant say there wont be any effect at all at speeds lower than 200...
Mostly the spoilers will help grip the road better while taking fast turns rather than at top speed runs on a straight...

anupam9055 : are you sure you did 175 in your car ? has it been modded at all?
since it is good for abt 155 (maybe 165 on the speedo)
also all Indicas (Petrol) have a spoiler......as far as I know

but agree that the car is very solid at speeds upto 120/125 (my personal max upto now)

3rd June 2005, 10:44	#1
tsk1979 Team-BHP Support Join Date: Feb 2005 Location: San Jose, CA Posts: 23,717 Thanked: 22,825 Times View My Garage	Cure for lightfootedness... Hi, I have found that while driving at extreme speeds(150-160 range) the car gets light footed. As if it has shed 500kilos. As in the steering gets exremely light. This problem is not at all there before 140. The tyres are 155/80R13. To cure this problem are wider tyres advised or a spoiler will do the trick. Also how much impact on top speed will the spoiler have. Are there any scientificaly designed spoilers available for hatches. Most of the after market stuff i have seen are cosmetic jobs with no measuments on angle and stuff. I usually run 2-3psi above manufacturer recommendation for high speeds.
	() Thanks

3rd June 2005, 10:52	#2
hrag BANNED Join Date: Nov 2004 Location: Bangalore / Madras Posts: 1,982 Thanked: 31 Times	If you are talking about the Indica, yes. The steering does feel light at high speeds. The feeling starts around 130 - 135 kmph. Have you tried these speeds with the recommended pressures? hrag
	() Thanks

3rd June 2005, 11:19	#3
tsk1979 Team-BHP Support Join Date: Feb 2005 Location: San Jose, CA Posts: 23,717 Thanked: 22,825 Times View My Garage	Indica does not cross 130(DLS i have). this i am talking about the Getz. At around 160 i felt as if the car had slightly lifted off. I am wondering wether the 155 width tyres are to blame or is it the aerodynamics. I am scared to drive at recommended pressures because they are the "minimum" and risk of tyre burst is high at those pressures.
	() Thanks

3rd June 2005, 11:33	#4
drifter Senior - BHPian Join Date: Sep 2004 Location: Bombay Posts: 1,488 Thanked: 75 Times View My Garage	The suspension causes this....changing the tyres wont help much in lightfootedness....but upgrade from 155s to atleast 175 for the getz...actually i didnt know the getz came with 155s. 175s will make the steering a bit heavier...which will help a little at high speeds. Drifter
	() Thanks

3rd June 2005, 11:36	#5
nitrous Senior - BHPian Join Date: May 2004 Location: UAE/Lon/Madras Posts: 6,965 Thanked: 325 Times View My Garage	yes man, the tyres are biggest culprits. try to upsize asap. atleast 175/70/R13
	() Thanks

3rd June 2005, 11:50	#6
tsk1979 Team-BHP Support Join Date: Feb 2005 Location: San Jose, CA Posts: 23,717 Thanked: 22,825 Times View My Garage	The GL does! Since tyres dont help, wont a spoiler increase the downforce and help in this case. On a related note, i may be buying indigo Tdi in near future which is capable of 150kmph. Would it be useful to put in a spoiler. I have used indigo for about 1K kms, and found high speed handling to be stable at 130-140. Any other user can give me feedback regarding handling at higher speeds?
	() Thanks

3rd June 2005, 12:48	#8
anoops BHPian Join Date: Mar 2004 Location: bangalore Posts: 183 Thanked: 3 Times	WOW you've hit speeds of 150-160 in your indicar???...super!!... sorry just read the rest of the post...still these speeds are possible on a getz..pretty good eh?? Last edited by anoops : 3rd June 2005 at 12:51.
	() Thanks

3rd June 2005, 13:05	#10
RX135 Senior - BHPian Join Date: Dec 2004 Location: pune Posts: 2,106 Thanked: 75 Times	@steer, at 150+, the effect may not be as drastic as 200+ speeds, but still it should be able to provide downforce to assist (or mess up) handling. Race cars would require far more downforce due to their extreme powered engines, which will not be the case with road cars. So, installing an OEM spoiler should be some help, especially for cars which oversteer.
	() Thanks

3rd June 2005, 15:22	#12
speedsatya Senior - BHPian Join Date: May 2004 Location: bangalore/manga Posts: 3,169 Thanked: 738 Times View My Garage	try keepin a gunny bag or two in the boot if driving alone. also spoilers on almost all cars simply cosmetic. actually its only above 120kph that feather weighted sports cars do tend to lift of fthe ground .so the spoiler comes into the picture only after these speeds.thats the reason wven in some porsches the spoiler comes out only after 120kph. about the getz,simply adding a spoiler will only increase its cd figures.as itis its too heavy to be airborne. and if u feel its light at 160 the simple answer is "dont drive at 160".its not all meant to be driven at those speeds.a limit of 120 kph on our roads is more than enough.
	() Thanks

3rd June 2005, 16:05	#13
anupam9055 Posts: n/a	guys i have done 175kmph in my indica petrol (lsi) of course with 175/60/13R rubbers and even at that speed the car felt rock solid .............. the car is very stable at any speed and at any condition that to with out any spoiler or anything................
	() Thanks

3rd June 2005, 17:18	#15
Abhay BHPian Join Date: Apr 2005 Location: Pune Posts: 727 Thanked: 11 Times	I am sure the spoilers are more to do with cosmetics than downforce on these hatches although cant say there wont be any effect at all at speeds lower than 200... Mostly the spoilers will help grip the road better while taking fast turns rather than at top speed runs on a straight... anupam9055 : are you sure you did 175 in your car ? has it been modded at all? since it is good for abt 155 (maybe 165 on the speedo) also all Indicas (Petrol) have a spoiler......as far as I know but agree that the car is very solid at speeds upto 120/125 (my personal max upto now)
	() Thanks