Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 19th April 2007, 11:55   #1
BHPian
 
Join Date: Sep 2005
Location: Mumbai, London
Posts: 54
Thanked: 9 Times
Default Wheels in air dont rotate : Why ?

hi friends,

i was watching a video of some cars pulling stunts like driving on 2 wheels. no not a wheelie. they were like driving on two left wheels. im sure u have seen this before. now the thing is both the right side wheels (which were in the air, did not rotate.) why is it so.

first i thought maybe cuz of differential unit. then i read that in differential, same torque is supplied to both wheels but rotation speed is different. wheel with less friction rotates faster.

in that case the wheel in the air should rotate even faster. why is it stationary? also confirm if differential unit is present on both the axles.
worrisomebear is offline   Reply With Quote
Old 19th April 2007, 12:17   #2
Senior - BHPian
 
esteem_lover's Avatar
 
Join Date: Jul 2006
Location: Madras/Py
Posts: 7,554
Thanked: 445 Times
Default

Could it be simply because there was no acceleration, hence no power transmitted to the wheels ?
esteem_lover is offline   Reply With Quote
Old 19th April 2007, 12:34   #3
BHPian
 
Join Date: Mar 2007
Location: Delhi
Posts: 254
Thanked: 2 Times
Default

Quote:
Originally Posted by worrisomebear View Post
hi friends,

wheel with less friction rotates faster.

in that case the wheel in the air should rotate even faster. why is it stationary? also confirm if differential unit is present on both the axles.
Differential unit is present only on live axle, if it is a 4wd then only diiferentials are there on both axles as both are live, in addition to a transfer case.

You are right the wheel in air, owing to less restriction should spin more, unless there is a specific arrangement for locking the wheel in air, so as to transmit whole power to wheel in contact with graound.
arunforu1 is offline   Reply With Quote
Old 19th April 2007, 13:50   #4
BHPian
 
Join Date: Sep 2005
Location: Mumbai, London
Posts: 54
Thanked: 9 Times
Default

myself confused right now..i dnt know why
worrisomebear is offline   Reply With Quote
Old 19th April 2007, 13:58   #5
BHPian
 
sbasak's Avatar
 
Join Date: Nov 2005
Location: CCU-LTN
Posts: 607
Thanked: 8 Times
Default

Most probably they are governed by TORque SENsing Differential
It sends 100% of available torque to the wheel which has the traction (i.e. to the wheel in the ground in this case).

Search in Google for Torsen differential and you'll get lots of info.

Example
Torsen General Frequently Asked Questions page

Last edited by sbasak : 19th April 2007 at 13:59.
sbasak is offline   Reply With Quote
Old 19th April 2007, 14:42   #6
Distinguished - BHPian
 
Technocrat's Avatar
 
Join Date: Feb 2004
Location: Mid West
Posts: 14,900
Thanked: 2,492 Times
Default

I think this kind of setup is available even in the Mitsubishi EVO remember hearing something like this in a TG video.
Technocrat is offline   Reply With Quote
Old 19th April 2007, 15:40   #7
BHPian
 
rishibravo's Avatar
 
Join Date: Jul 2006
Location: New Delhi
Posts: 579
Thanked: 6 Times
Default

i think it happens in all the cars and the reason is differential.
rishibravo is offline   Reply With Quote
Old 19th April 2007, 15:54   #8
Distinguished - BHPian
 
Technocrat's Avatar
 
Join Date: Feb 2004
Location: Mid West
Posts: 14,900
Thanked: 2,492 Times
Default

Sar because of differential only the wheel should move. plese ready previous posts. Unless it has the TORque SENsing Differential as stated by sbasak the wheel should rotate
Technocrat is offline   Reply With Quote
Old 19th April 2007, 15:58   #9
SLK
Senior - BHPian
 
SLK's Avatar
 
Join Date: Feb 2004
Location: DL XX XX XXXX
Posts: 1,290
Thanked: 185 Times
Default

If differential was the answer.. the wheel in air is the only one that is supposed to move...

I say its just the momentum of the car... they pick up speed... and while doing the stunt don't accelerate at all... just let it roll.

Otherwise if the wheels in air are completely stopped... they might have some kind of a single sided brake!
SLK is offline   Reply With Quote
Old 19th April 2007, 16:58   #10
Senior - BHPian
 
v1p3r's Avatar
 
Join Date: Feb 2005
Location: BLR - chasing cars...
Posts: 4,836
Thanked: 26 Times
Default

Limited slip differential. Or zero throttle.
v1p3r is offline   Reply With Quote
Old 19th April 2007, 17:47   #11
BHPian
 
Jomz's Avatar
 
Join Date: Sep 2006
Location: Detroit, MI,USA
Posts: 810
Thanked: 289 Times
Default

Quote:
Originally Posted by v1p3r View Post
Limited slip differential. Or zero throttle.
With Limited slip differential it should rotate right..
Jomz is offline   Reply With Quote
Old 19th April 2007, 18:29   #12
Senior - BHPian
 
ananthkamath's Avatar
 
Join Date: Jul 2005
Location: USA
Posts: 1,194
Thanked: 46 Times
Default

Quote:
Originally Posted by sbasak View Post
Most probably they are governed by TORque SENsing Differential
It sends 100% of available torque to the wheel which has the traction (i.e. to the wheel in the ground in this case).

Search in Google for Torsen differential and you'll get lots of info.

Example
Torsen General Frequently Asked Questions page

wrong, the torsen doesnt work when one of the wheels is in the air.
ananthkamath is offline   Reply With Quote
Old 19th April 2007, 18:42   #13
Senior - BHPian
 
nitrous's Avatar
 
Join Date: May 2004
Location: UAE/Lon/Madras
Posts: 6,966
Thanked: 282 Times
Default

Differential lock is one probable reason.
nitrous is offline   Reply With Quote
Old 19th April 2007, 19:15   #14
Senior - BHPian
 
v1p3r's Avatar
 
Join Date: Feb 2005
Location: BLR - chasing cars...
Posts: 4,836
Thanked: 26 Times
Default

Quote:
Originally Posted by Jomz View Post
With Limited slip differential it should rotate right..
No. With an LSD the wheel in the air won't rotate. Torque is supplied to the wheel that has traction.

But in this case, it's 99% because they are cruising with zero throttle.
v1p3r is offline   Reply With Quote
Old 19th April 2007, 19:17   #15
Senior - BHPian
 
headers's Avatar
 
Join Date: May 2006
Location: Greater Chennai
Posts: 4,589
Thanked: 454 Times
Default

camera trick is the answer.

As many of you pointed out..the wheel in the air is supposed to rotate faster than the one on the road. Any kind of diff including Diff lock..WILL make the wheel rotate and NOT otherwise..
headers is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why dont car manufacturers adopt standard naming conventions for variants anujmishra The Indian Car Scene 30 11th February 2014 10:51
Why dont we have GROUP orders/buys here ? black12rr Shifting gears 7 28th August 2009 10:25
some light glowing in dash - dont know why rajivanoj Technical Stuff 13 18th December 2008 11:50
Why dont we see column mounted gear shifters anymore? deva kuduvalli Technical Stuff 10 25th July 2008 10:02
why dont we have this ? normally_crazy Shifting gears 4 23rd October 2004 21:30


All times are GMT +5.5. The time now is 16:20.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks