Caster, mystery |
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Caster, mystery |
Randal |
Jun 1 2013, 03:36 PM
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#1
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Advanced Member Group: Members Posts: 4,446 Joined: 29-May 03 From: Los Altos, CA Member No.: 750 |
I know how to set up toe in and camber, but not caster.
Questions: How do you measure it and then reset it. Also what is the stock caster setting and how will adding caster impact the amount of force needed to turn the wheel? Also understand that adding caster will impact toe in and camber. At what setting does this impact begin. All help appreciated. |
J P Stein |
Jun 1 2013, 06:26 PM
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#2
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
Caster is the angle off vertical in the side view that the strut sits. ...leaned back on top. On a 914 it is set about 5.5 deg or more.
Caster does effect camber when the wheel is truned......the outside tire goes negative & the inside positive. Since camber, toe, & camber are all set with strut movement, they is all set at once....juggled, if you will, to what you want within the limits of adjustment. I like all the caster you can get on a 914....close to 6 deg. This puts a good hunk of negative camber into the outside front durring conering. Here's an old pic that shows the effect pretty well. Note the left front wheeel. Attached image(s) |
Randal |
Jun 2 2013, 12:10 PM
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#3
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Advanced Member Group: Members Posts: 4,446 Joined: 29-May 03 From: Los Altos, CA Member No.: 750 |
Caster is the angle off vertical in the side view that the strut sits. ...leaned back on top. On a 914 it is set about 5.5 deg or more. Caster does effect camber when the wheel is truned......the outside tire goes negative & the inside positive. Since camber, toe, & camber are all set with strut movement, they is all set at once....juggled, if you will, to what you want within the limits of adjustment. I like all the caster you can get on a 914....close to 6 deg. This puts a good hunk of negative camber into the outside front durring conering. Here's an old pic that shows the effect pretty well. Note the left front wheeel. So what do you measure the 5.5 degrees against. The strut or ? |
J P Stein |
Jun 2 2013, 12:28 PM
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#4
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
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koozy |
Jun 2 2013, 02:56 PM
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#5
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Senior Member Group: Members Posts: 651 Joined: 21-July 07 Member No.: 7,931 Region Association: None |
Or, you can download an angle app on yer iPhone and slap it on the strut to measure the degrees.. Pick yer poison.
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Randal |
Jun 2 2013, 04:53 PM
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#6
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Advanced Member Group: Members Posts: 4,446 Joined: 29-May 03 From: Los Altos, CA Member No.: 750 |
Caster is the angle off vertical in the side view that the strut sits. ...leaned back on top. On a 914 it is set about 5.5 deg or more. Caster does effect camber when the wheel is truned......the outside tire goes negative & the inside positive. Since camber, toe, & camber are all set with strut movement, they is all set at once....juggled, if you will, to what you want within the limits of adjustment. I like all the caster you can get on a 914....close to 6 deg. This puts a good hunk of negative camber into the outside front durring conering. Here's an old pic that shows the effect pretty well. Note the left front wheeel. So what do you measure the 5.5 degrees against. The strut or ? I have some good angle measurement tools and my iphone app, so will try both. If the factory setup is 5.5 degrees (towards the driver) then what do racers typically run? |
koozy |
Jun 2 2013, 05:25 PM
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#7
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Senior Member Group: Members Posts: 651 Joined: 21-July 07 Member No.: 7,931 Region Association: None |
Most folks max it out but that makes it heavy on the hands. I'm using a bit less. It makes for a light steering car with all that rubber I have up front. If I switch to a narrower front tire I may go back to maxed out.
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URY914 |
Jun 2 2013, 05:58 PM
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#8
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I built the lightest 914 in the history of mankind. Group: Members Posts: 120,863 Joined: 3-February 03 From: Jacksonville, FL Member No.: 222 Region Association: None |
Mine is maxed out.
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SirAndy |
Jun 2 2013, 10:16 PM
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#9
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Resident German Group: Admin Posts: 41,658 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
Just did this today. Mine was way off from left to right which made for some funny driving.
Maxed it out which is about 6 degrees with the stock strut tops. (IMG:style_emoticons/default/driving.gif) |
J P Stein |
Jun 2 2013, 10:28 PM
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#10
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
Ya'll got an app for my cracked & bleedin' ass?
Kids these days...... |
koozy |
Jun 2 2013, 11:55 PM
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#11
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Senior Member Group: Members Posts: 651 Joined: 21-July 07 Member No.: 7,931 Region Association: None |
Ya'll got an app for my cracked & bleedin' ass? Kids these days...... Will this help? https://play.google.com/store/apps/details?...cButt&hl=en |
Randal |
Jun 3 2013, 08:20 AM
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#12
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Advanced Member Group: Members Posts: 4,446 Joined: 29-May 03 From: Los Altos, CA Member No.: 750 |
Just did this today. Mine was way off from left to right which made for some funny driving. Maxed it out which is about 6 degrees with the stock strut tops. (IMG:style_emoticons/default/driving.gif) So that was the weird handling "thing" we were talking about. Glad you found it. |
Randal |
Jun 3 2013, 10:18 AM
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#13
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Advanced Member Group: Members Posts: 4,446 Joined: 29-May 03 From: Los Altos, CA Member No.: 750 |
Just did this today. Mine was way off from left to right which made for some funny driving. Maxed it out which is about 6 degrees with the stock strut tops. (IMG:style_emoticons/default/driving.gif) Is this the correct way: I put a straight edge across the cup that holds the shock bolt. My iphone app was flipping back between 9 and 10 degrees(*). So given that the floor is 2 degrees my caster is 8 degrees? Not sure if this is the way to measure it, but isn’t that a bit high and a cause for my hard steering? (*) The reading on the picture looks like 19 degrees, but the camera caught the app switching from 9 to 10 degrees. |
SirAndy |
Jun 3 2013, 11:26 AM
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#14
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Resident German Group: Admin Posts: 41,658 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
So that was the weird handling "thing" we were talking about. Glad you found it. Most of it it seems. There's still a bit of a "mushy" feeling and the alignment is not yet dead on, but the bouncing in corners is almost gone. I know i still have a bit bump steer due to my current ride height (way up) and once that is dialed out and the alignment is spot on the car should drive *much* better. The caster was off by several degrees between left and right. No idea how that happened. (IMG:style_emoticons/default/blink.gif) |
r_towle |
Jun 3 2013, 11:29 AM
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#15
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Custom Member Group: Members Posts: 24,584 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
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Matt Romanowski |
Jun 3 2013, 12:48 PM
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#16
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Senior Member Group: Members Posts: 878 Joined: 4-January 04 From: Manchester, NH Member No.: 1,507 |
Just did this today. Mine was way off from left to right which made for some funny driving. Maxed it out which is about 6 degrees with the stock strut tops. (IMG:style_emoticons/default/driving.gif) Is this the correct way: I put a straight edge across the cup that holds the shock bolt. My iphone app was flipping back between 9 and 10 degrees(*). So given that the floor is 2 degrees my caster is 8 degrees? Not sure if this is the way to measure it, but isn’t that a bit high and a cause for my hard steering? (*) The reading on the picture looks like 19 degrees, but the camera caught the app switching from 9 to 10 degrees. You want to measure on the strut, not the cap. Caster is the measurement of the kingpin angle viewed from the side of the car. For MacPherson front ends, it's the angle of the strut. Google "alignment caster" and you'll see what you are supposed to be measuring. Edit: Read the other scale - it looks like you have about 3 degrees (90-87). I would still say you should measure off the strut itself. |
Randal |
Jun 3 2013, 02:13 PM
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#17
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Advanced Member Group: Members Posts: 4,446 Joined: 29-May 03 From: Los Altos, CA Member No.: 750 |
Thanks for the advice!
OK so measure against the strut as per the picture, i.e., the red arrow? |
Woody |
Jun 3 2013, 03:55 PM
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#18
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Sandbox Rabblerouser and head toilet scrubber Group: Members Posts: 3,858 Joined: 28-December 10 From: San Antonio Texas Member No.: 12,530 Region Association: Southwest Region |
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SirAndy |
Jun 3 2013, 04:08 PM
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#19
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Resident German Group: Admin Posts: 41,658 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
I would measure below the dust cover on the actual strut itself. My car is maxed out at 5.5 degrees. (IMG:style_emoticons/default/agree.gif) Don't use the dust cover (if you still have one), use the strut itself. Now would also be a good time to see if there's a difference in angle between the strut and the shaft. (IMG:style_emoticons/default/popcorn[1].gif) |
J P Stein |
Jun 3 2013, 04:21 PM
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#20
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Irrelevant old fart Group: Members Posts: 8,797 Joined: 30-December 02 From: Vancouver, WA Member No.: 45 Region Association: None |
Measure front face of strut tube....or insert (piston rod) in same, that is more uinform.
Keep the instrument parallell to the tube in X & Y. App that with the machined surface of your cell phone. Attached image(s) |
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