(Note: Donations are not tax deductible)

This is a public forum. The opinions expressed here don't
necessarily reflect the feelings of The Folks That Run The Site (that's us)
unless we explicitly say so, ok?


Forum's been "upgraded".
Things will look a bit different.
A *few* posts might have gotten lost in the crossover.
PM bobc with problems, or post in "Website Suggestions".

Author Topic: caster  (Read 4127 times)

0 Members and 1 Guest are viewing this topic.

Online bob

  • Jr. Member
  • **
  • Posts: 47
  • Age: 67
  • Location: sierraville calif
  • Sierraville, CA
caster
« on: August 21, 2018, 10:58:14 AM »
what would be correct amount of caster, I know more is better for straight line stability, but how much is more, and is to much counter productive  thanks

Offline 7800ebs

  • Full Member
  • ***
  • Posts: 159
    • http://quickturnparts.com/index.html
Re: caster
« Reply #1 on: August 21, 2018, 12:57:43 PM »
I have less than 10 degrees as I remember..

too much and you will get a wheel wobble.. been there, done that

bob dalton
flashpoint

Offline Stan Back

  • Hero Member
  • *****
  • Posts: 5051
  • Location: San Berdoo
Re: caster
« Reply #2 on: August 21, 2018, 02:22:58 PM »
We've got 13ยบ.  Never a wobble, but won't keep you out of the spin cycle.
Member of the San Berdoo Roadsters -- "California's Most-Exclusive Roadster Club".
Celebrating 67th anniversary of racing on the salt.

Offline hotschue

  • Full Member
  • ***
  • Posts: 254
  • Location: Ocala, Florida
Re: caster
« Reply #3 on: August 21, 2018, 03:38:23 PM »
Built axle 13 degrees (same as a funny car) machined spindle, hub and wheels to achieve "0" scrub radius.   You can just about take your hands off the steering wheel......
Udo Horn
221.559 D/CGC '03
178.835 G/GMS '10

Online bob

  • Jr. Member
  • **
  • Posts: 47
  • Age: 67
  • Location: sierraville calif
  • Sierraville, CA
Re: caster
« Reply #4 on: August 21, 2018, 06:51:19 PM »
thanks for the input , sounds like about 13* is about right. I better not listen to my expert buddy who kind of knows about alignment, and not set it at 24*. dangerous combo.

Offline kiwi belly tank

  • Hero Member
  • *****
  • Posts: 2555
  • Age: 167
  • Location: Lava Hot Springs Idaho
Re: caster
« Reply #5 on: August 22, 2018, 01:13:59 AM »
There are lots of variables to the correct answer & that includes what your car is, what type of suspension (if any), what the other geometry of your front end is, how fast is it going & where,..........
  Sid.

Offline revolutionary

  • Sr. Member
  • ****
  • Posts: 524
  • Location: Windermere, FL
Re: caster
« Reply #6 on: August 23, 2018, 09:39:40 AM »
I built my spindles with 14 deg KPI and set the caster at 13. Ended up with about .5" scrub using 25" tires. Going to a taller tire I could take some scrub out, but I never felt it make any moves during SW this year.
Breaking Wind #9614
  ECTA Record AA/BGALT 214.8
  SCTA Bonneville PB AA/BGALT 237.4
Breaking Wind "Spirit of Effluvium" #451
  SCTA Bonneville Record SC/BF100 48.931

Offline Bob Drury

  • Hero Member
  • *****
  • Posts: 2567
  • Age: 72
  • Location: Vancouver,Wa.
Re: caster
« Reply #7 on: September 07, 2018, 11:24:30 PM »
  Back in the sixties most of the fuel dragsters ran 25 degrees + or - and when they pushed down to the starting line to make the tight U-turn to stage the wheels would flop over like some of the "Ladies" in Wells, Nevada.
  Enter the funny car era around 1966 with steel bodies and straight axles they ran darn near that much and into the early to mid seventies even with torsion bar suspension or coil over independant suspension, a lot of funny cars still ran a ton of caster. The results were often not pretty.
  I watched Twig Ziegler (who was one to back up reeeal fast) end up looking like a turtle after the wheels flopped on the Pizza Haven Plymouth Satellite.  It's pretty hard to look graceful when hanging upside down waiting for a dozen people to roll You back over so You don't break Your fu*king neck getting out.
  p.s.  How in the hell do I remember that when I don't even know what day it is anymore?
 

                                                                                     "One Run", out................................................ :roll: :-o :mrgreen:
« Last Edit: September 07, 2018, 11:28:17 PM by Bob Drury »
Bob Drury

Offline Stainless1

  • Administrator
  • Hero Member
  • ***
  • Posts: 7262
  • Age: 68
  • Location: Near Furley and Kechi KS
  • Robert W. P. "Stainless" Steele
Re: caster
« Reply #8 on: September 08, 2018, 07:39:09 AM »
One Run... it is easy to remember what day it is....if you remember there are only 3 days of importance to you... Yesterday, the last day you remember....Today, this is today, and Tomorrow, it is.... well tomorrow...  :roll:  :-D
Work on it, there will be a test tomorrow  :cheers:

Edit: I guess I should comment on the subject... we ran a flopper front on the Bockscar for many years... about 36 degrees, no scrub.  A couple of years ago I changed it to 12ish.... no scrub.... it is easier to back up, and we lost that pressure area in the steering that you could tell you were about to steer the car.
« Last Edit: September 08, 2018, 07:42:57 AM by Stainless1 »
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline floydjer

  • Hero Member
  • *****
  • Posts: 2857
  • Age: 61
  • Location: grand rapids, michigan
  • "There is no duck side of the moon..."
Re: caster
« Reply #9 on: September 11, 2018, 01:48:45 PM »
Might be worthwhile to place scales under each wheel and see what effect the various caster angles have on camber gain/loss and weight jacking.
I`d never advocate drugs,alcohol,violence or insanity to anyone...But they work for me.

Offline SPARKY

  • Global Moderator
  • Hero Member
  • ***
  • Posts: 6682
  • Age: 77
  • Location: Phoenix
Re: caster
« Reply #10 on: September 12, 2018, 11:55:17 AM »
Costello runs 0  ZERO 
 I run three----

What we both are trying to do is not have steering inputs weight jack the car when you are down course---Caster with scrub radius definitely will induce the rear tires steering the car.
Miss LIBERTY,  changing TKI  to noise, dust and RUST!!!

The # 1 issue is: TO KEEP THE REPUBLIC      
   Center for Self Governance            tncsg.org     mrspowell.org

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

Offline floydjer

  • Hero Member
  • *****
  • Posts: 2857
  • Age: 61
  • Location: grand rapids, michigan
  • "There is no duck side of the moon..."
Re: caster
« Reply #11 on: September 13, 2018, 07:14:31 AM »
careful Sparky.....You`re getting dangerously close to agreeing with me.... :cheers:
I`d never advocate drugs,alcohol,violence or insanity to anyone...But they work for me.

Offline Rex Schimmer

  • Hero Member
  • *****
  • Posts: 2345
  • Age: 76
  • Location: Fulton, CA
  • Only time and money prevent completion!
Re: caster
« Reply #12 on: September 13, 2018, 10:10:50 PM »
Solid suspension cars, like Sparky's, are especially sensitive to jacking caused by wheel offset and caster. There is effectively zero suspension compliance and if the chassis is stiff in torsion, which Sparky's certainly appears to be, small vertical movements of a wheel can cause large amounts of cross chassis weight transfer, i.e. jacking. Pretty easy to understand why Sparky wants to minimizing caster and wheel offset.

Rex
Rex

Not much matters and the rest doesn't matter at all.

Offline SPARKY

  • Global Moderator
  • Hero Member
  • ***
  • Posts: 6682
  • Age: 77
  • Location: Phoenix
Re: caster
« Reply #13 on: September 14, 2018, 01:22:19 PM »
careful Sparky.....You`re getting dangerously close to agreeing with me...

And that would be a wonderful thing right  :-D
Miss LIBERTY,  changing TKI  to noise, dust and RUST!!!

The # 1 issue is: TO KEEP THE REPUBLIC      
   Center for Self Governance            tncsg.org     mrspowell.org

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

Offline manta22

  • Hero Member
  • *****
  • Posts: 3390
  • Age: 80
  • Location: Tucson, AZ
  • What, me worry?
Re: caster
« Reply #14 on: September 20, 2018, 04:44:43 PM »
I run 7 degrees of caster FWIW.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ