Results 1 to 18 of 18

Thread: Why does my car lift a wheel in a corner?

  1. #1
    Registered User steve91tt's Avatar
    Member ID
    CZCC-20531
    Join Date
    Dec 2009
    Location
    Houston
    Posts
    802

    Default Why does my car lift a wheel in a corner?

    I noticed that my car tends to come very close to lifting the inside front wheel in a corner on the track.

    Click image for larger version. 

Name:	IMG_14352.jpg 
Views:	322 
Size:	98.7 KB 
ID:	50796Click image for larger version. 

Name:	IMG_14659.jpg 
Views:	704 
Size:	88.5 KB 
ID:	50798Click image for larger version. 

Name:	IMG_14380.jpg 
Views:	424 
Size:	85.7 KB 
ID:	50799

    I assume this is a symptom of something being off in my alignment or suspension geometry. Anyone dealt with this before in a 240Z?
    Steve

    1973 240Z (daily driver)
    1971 240Z (track car)

  2. #2
    Registered User LeonV's Avatar
    Member ID
    CZCC-19146
    Join Date
    Apr 2009
    Location
    Bay Area, CA
    Posts
    1,961

    Default

    It actually doesn't have anything to do with alignment or geometry. It's dependent upon the lateral force generated, and the "axle's" cornering stiffness. When the inside wheel lifts, that means that all the weight has been transferred and there will be no additional lateral force generated at that end.
    2/74 260Z

  3. #3
    Low Budget/High Value
    Member ID
    CZCC-20342
    Join Date
    Oct 2009
    Location
    Washington County, OR
    Posts
    3,629

    Default

    I read an article in one of the car magazines years ago about a 67 Malibu turned in to a fast track car. The owner adjusted his anti-sway bar settings to lift the front wheel for photos, but he didn't race it that way. There was commentary in the article about how the suspension was so tunable that the owner asked the photographer how high he wanted the wheel for the shot.

    So I would guess sway bar adjustments as a possible solution but I'm sure the track guys will know more.

    Edit - by the way, you didn't say if you wanted more lift or less. Looks cooler with more...
    Last edited by Zed Head; 01-23-2012 at 08:38 PM.

  4. #4
    Registered User steve91tt's Avatar
    Member ID
    CZCC-20531
    Join Date
    Dec 2009
    Location
    Houston
    Posts
    802

    Default

    Would you then stiffen the rear sway bar to keep the front tire on the ground?
    Steve

    1973 240Z (daily driver)
    1971 240Z (track car)

  5. #5
    Registered User LeonV's Avatar
    Member ID
    CZCC-19146
    Join Date
    Apr 2009
    Location
    Bay Area, CA
    Posts
    1,961

    Default

    Quote Originally Posted by steve91tt View Post
    Would you then stiffen the rear sway bar to keep the front tire on the ground?
    Yes, that's one way to do it. That would shift your cornering stiffness distribution to the rear, thus delaying full weight transfer at the front. That should make the car more neutral. When the inside front lifts, you're increasing understeer (unless you break the rears loose). You may be better off downsizing the front bar to somewhat decouple the left and right wheels, however that will likely dictate an increase in spring rate.
    2/74 260Z

  6. #6
    Nova Scotia,Canada,Earth Blue's Avatar
    Member ID
    CZCC-7641
    Join Date
    Jan 2005
    Location
    NS
    Posts
    4,085

    Default


    Lots of Datsun Examples in this one.




    or wait for John to chime in.
    There is scarcely anything in the world that some man cannot make a little worse, and sell a little more cheaply.
    The person who buys on price alone is this man's lawful prey.


    John Ruskin (1819 - 1900)



    ZCars in Eastern Canada seaport ready for shipment to Europe

    http://ZSportCanada.com


  7. #7
    Registered User
    Member ID
    CZCC-5121
    Join Date
    Oct 2003
    Location
    Seattle, WA
    Posts
    2,362

    Default

    The question is: "Is the car faster lifting a tire or not lifting a tire?" Yes, if you lift a front tire off the ground that might cause you to have less traction available to turn the car at that particular part of the turn, but maybe you gained more traction in the rear for acceleration and realized a net gain. Usually the front tire comes up when the power goes on. You can stiffen the rear to stop it, but this might make it harder to put the power down.

    There is more info on this kind of thing at Hybrid Z than you will find here.
    Jon

  8. #8
    Registered User steve91tt's Avatar
    Member ID
    CZCC-20531
    Join Date
    Dec 2009
    Location
    Houston
    Posts
    802

    Default

    Blue, I picked up a copy of "How to Make Your Car Handle" from Amazon this morning. Looks like a great book.

    Jon, I will dig into Hybrid Z and see what I can find on the subject.
    Steve

    1973 240Z (daily driver)
    1971 240Z (track car)

  9. #9
    Crumudgeon
    Member ID
    CZCC-798
    Join Date
    Apr 2000
    Location
    La Habra, CA USA
    Age
    59
    Posts
    1,374

    Default

    Looking at the pictures the balance seems about right. Maybe reduce rear roll stiffness a bit. With these cars you generally want the inside front tire very light in a corner. Helps with traction out of the corner.

    Click image for larger version. 

Name:	RODatLVMS.jpg 
Views:	208 
Size:	46.3 KB 
ID:	50801

    You as a driver need to relax your shoulders and tighten your shoulder harnesses so you don't lean into the corner as much and don't have to hang on to the steering wheel.

  10. #10
    Registered User steve91tt's Avatar
    Member ID
    CZCC-20531
    Join Date
    Dec 2009
    Location
    Houston
    Posts
    802

    Default

    Thanks John. Good to know that it's typical for these cars to have a light inside wheel in a corner. I've been working to be as relaxed as possible on the track but I don't have a harness and even with a decent seat and the stock belts as tight as I can make them I'm still fighting to keep my body planted in a corner. This should all change soon as I'm taking my car to a builder tonight to have a custom cage made and 6 point harness installed. Hopefully that will help with safety and stop me from being thown around so much in the corners.
    Steve

    1973 240Z (daily driver)
    1971 240Z (track car)

  11. #11
    Supporting Member Zedyone_kenobi's Avatar
    Member ID
    CZCC-16285
    Join Date
    Mar 2008
    Location
    Houston
    Age
    46
    Posts
    2,919
    Blog Entries
    2

    Default

    The 6 point harness is the money buddy.

    But a poor mans way to hold your butt into your stock Datsun seat was given to me by Frank C. on this board.

    A nice roll of kitchen drawer liner, that rubberized bubbly stuff. I put in on my Datsun last time around Grandsport and it was AMAZING how stuck to the seat I was...
    1971 240Z HLS30-38691
    93.9% done and getting better every day
    Now with 100% more DATSUN SPIRIT L28 Power
    1968 Datsun 2000 SRL311-03416

  12. #12
    Registered User steve91tt's Avatar
    Member ID
    CZCC-20531
    Join Date
    Dec 2009
    Location
    Houston
    Posts
    802

    Default

    I used the rubberized liner trick until I got the racing bucket. I agree it works great on the stock seats. I don't have a problem with my butt moving in the new seat it's my head and shoulders that are getting tossed around. Yet again, my swollen head gets me in trouble.
    Steve

    1973 240Z (daily driver)
    1971 240Z (track car)

  13. #13
    Semi-retired admin Arne's Avatar
    Member ID
    CZCC-8596
    Join Date
    Jun 2005
    Location
    Eugene, Oregon, USA
    Age
    62
    Posts
    8,465

    Default

    I'll add that lots of RWD cars do this. Watch a 911 some time. Since the rear engine car is rather light on the front, the inside front may be several inches in the air - and that's normal. FWD are the other way around. I've got pictures somewhere (film, not digital) of my old Scirocco (with lots of sway bar) in an auto-x with at least 6" of air under the inside rear wheel. Watch a Rabbit on the track some time - it can be amusing.
    Arne - Former owner, HLS30-37705, 7/71, 905 Red
    Car blogs - 240Z - Porsche 911

  14. #14
    Registered User Jeff G 78's Avatar
    Member ID
    CZCC-7975
    Join Date
    Mar 2005
    Location
    Northville, Michigan
    Age
    53
    Posts
    1,895

    Default

    I don't have near the stiffness John does, but my inside front gets light as well. This is with cut springs and aftermarket bars. This is my $500 crapcan racer.
    Jeff
    Northville, Michigan
    IZCC #1285
    '78 280 10:1 CR, Arizona Z Car header, urethane bushings, Tokico springs, Illumina struts, Panasports w/Hankook R-S2 225/50R16 tires, Maxima 105 amp alternator
    http://www.classiczcars.com/photopos...00&ppuser=7975
    '74 260Z BRE look-alike crap can for Optima Batteries ChumpCar World Series Racing racing
    https://www.facebook.com/Jeff.Grauer

  15. #15
    Registered User beermanpete's Avatar
    Member ID
    CZCC-21519
    Join Date
    Apr 2010
    Location
    Northridge, California, U.S.A.
    Age
    56
    Posts
    631

    Default

    Our car behaves similarly. The inside tire leans in enough to raise the outside 1/3 of the tire off the ground. Here is a shot from the track before we did any suspension work. Stock springs, dead shocks, no rear anti-sway bar.

    Click image for larger version. 

Name:	Turn 4 - Peter.jpg 
Views:	280 
Size:	143.1 KB 
ID:	50816

  16. #16
    Low Budget/High Value
    Member ID
    CZCC-20342
    Join Date
    Oct 2009
    Location
    Washington County, OR
    Posts
    3,629

    Default

    Look at the pictures on the front page here to see how the Porsches do it. More lift!

    http://rothsport-racing.com/

  17. #17
    Registered User
    Member ID
    CZCC-5121
    Join Date
    Oct 2003
    Location
    Seattle, WA
    Posts
    2,362

    Default

    Quote Originally Posted by beermanpete View Post
    Our car behaves similarly. The inside tire leans in enough to raise the outside 1/3 of the tire off the ground. Here is a shot from the track before we did any suspension work. Stock springs, dead shocks, no rear anti-sway bar.
    Control the roll (in this case it may be as much or more due to the inside suspension jacking up around the corner as it is the outside suspension compressing) and you'll fix that. This gets pretty technical and there are lots of different viewpoints on the subject which is why I didn't want to get into it here, but this post pretty much tells the story and you can follow it up from there if you like.

    http://forums.hybridz.org/index.php/...ost__p__617208
    Jon

  18. #18
    Registered User Jetaway's Avatar
    Member ID
    CZCC-16944
    Join Date
    May 2008
    Location
    Manteca, CA
    Age
    60
    Posts
    382

    Default

    Needs to pee?

    Chris

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Cowl Grille corner rubbers
    By Stevie P in forum Help Me !!
    Replies: 9
    Last Post: 01-05-2012, 03:23 PM
  2. Thunk and stiffness from one corner.
    By Z-Luke in forum Suspension and Steering (S30)
    Replies: 6
    Last Post: 03-31-2010, 09:04 PM
  3. The Mitty is just around the corner
    By SteveJ in forum Open Discussions
    Replies: 11
    Last Post: 03-24-2009, 09:21 AM
  4. Corner Balancing
    By gnosez in forum Suspension and Steering (S30)
    Replies: 1
    Last Post: 01-01-2009, 04:32 PM
  5. 240k corner weights?
    By mark105 in forum Open 240K Discussion
    Replies: 8
    Last Post: 12-09-2008, 02:48 AM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •