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Camber

Posted: 14 Oct 2013 22:54
by nick
My two cars have different camber angles. Both are negative but the '76 FHC seems to have a couple of degrees more than the '79 DHC. I did a course measurement by putting a carpenters square vertically against the tires and observed the angle between the square and the shop floor. I would estimate a couple of degrees difference between the two cars. The last time I had an alignment on the FHC they measured the camber at -.4 degrees and -.5 degrees. So the DHC is probably on the order of -1.5 to -2.0 degrees.

Because of this difference they handle quite differently. The FHC seems to want to oversteer much more than the DHC. I'm not happy with how the FHC feels. I know those angles are nonadjustable. So could I have some shorter than standard springs in there or would this be just a matter a of production variance? The car doesn't look any lower than it should so I am perplexed.

Image[img][IMG]http://i615.photobucket.com/albums/tt234/nickmi/TR7%201975/Yellow.jpg[/img]
nick
'79 TR7 DHC
'76 TR7 FHC

Posted: 14 Oct 2013 23:18
by Workshop Help
It would be my guess that over the nearly four decades, more than a few curbs have collided with the wheels/tires of your cars. I know mine certainly have. The solution was for my favorite brake & alignment shop, the one with all the grey haired men, to drag out the torch and special levers to heat straighten the spindles to strut tube angle, thus restoring the desired camber and castor settings.

I know the official factory service manual says only the toe-in is adjustable, but some things just have to be done.

Mildred Hargis

Posted: 14 Oct 2013 23:40
by Hasbeen
It is probably more like body sag, or bad major repair work. The strut towers have probably moved inwards, although it could be the stub axles are bent.

Run a tape across both your cars, find the difference, then find a car with no more than 1 degree of negative camber, & measure that. If they are materially different, talk to a top body shop, one with a body straightening rack, to see if they can true it up, without damaging anything else.

I had the 8 checked & squared up years ago, & it has not moved since. One front corner was high, & they pulled it down, or actually pushed the other up I think. I couldn't watch. They thought it was accident damage, although were not sure.

Ron [silverseven] will know more about this stuff, & will probably tell us.

I would not have more than 1 degree negative camber on a road car, & would check it out if it had more.

This is a very good argument for fitting a strut brace.

Hasbeen

Posted: 15 Oct 2013 20:24
by jeffremj
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Because of this difference they handle quite differently. The FHC seems to want to oversteer much more than the DHC. I'm not happy with how the FHC feels.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Before you try and do some heavy mods., why not swop all the wheels over and see if the oversteer follows the wheels.

Posted: 15 Oct 2013 21:33
by RadioGuy
Don't jump too hard or quick but..I have found that if I over inflate my front tires to about 42-45 psi my over-steer is eliminated or greatly reduced. Running at 32 or less psi has scared the poop out of me a few times...Not a pretty site [:I]

ImageImageImageImage
Maintained on Saturday…Drive on Fun-Day !!! 1976 FHC - 1980 DHC http://tinyurl.com/7rkonrx

Posted: 16 Oct 2013 09:51
by Beans
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Hasbeen</i>

... This is a very good argument for fitting a strut brace ... <hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
Agree, but the most likely cause is that the car with the most camber sits lowest (caused by sagged or lowered springs).
Check/compare the TCA angles when the cars are on a flat surface.

When I lowered 't Kreng many years ago it changed the camber from -0,5° to -2,0°.
It also changed the castor angle, lessening it by about 1°
The car handled fine in corners but was rather nervous in a straight line.

<center>Image
<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="3"><font color="red">My full Weblog</font id="red"></font id="size3"></b></u>[/url]</b></i></center>

Posted: 16 Oct 2013 13:31
by FI Spyder
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by RadioGuy</i>

Don't jump too hard or quick but..I have found that if I over inflate my front tires to about 42-45 psi my over-steer is eliminated or greatly reduced. Running at 32 or less psi has scared the poop out of me a few times...Not a pretty site [:I]
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Interesting. The stock psi is 24 front (very low). I often wondered if this was to induce under steer to preventing drivers from swamping ends and leaving the road (it didn't work as I've talked to a lot of people who said "I had/friend had one of those but I/he crashed it"). This under steer happened with the MGC that was corrected with higher (front) tire pressure. I like to run mine about 32 or just under. I only have some under steer on low speed cornering (like small traffic circles) but at speed curves it almost seems to turn through them it's self to the tires limit with any tire slippage being equal with no over or under steer. While this makes it a little harsh on lower speed rough road conditions, I like it otherwise so continue at that, not to mention even tire wear. No idea what caster/camber is, don't care as I'm happy with status quo.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT
Image

Posted: 16 Oct 2013 13:31
by nick
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by jeffremj</i>

[quote]Because of this difference they handle quite differently. The FHC seems to want to oversteer much more than the DHC. I'm not happy with how the FHC feels.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">Before you try and do some heavy mods., why not swop all the wheels over and see if the oversteer follows the wheels.
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Swapped wheels between the FHC and DHC. No change.

Image[img][IMG]http://i615.photobucket.com/albums/tt234/nickmi/TR7%201975/Yellow.jpg[/img]
nick
'79 TR7 DHC
'76 TR7 FHC

Posted: 16 Oct 2013 13:34
by nick
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Beans</i>

[quote]<i>Originally posted by Hasbeen</i>

... This is a very good argument for fitting a strut brace ... <hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
Agree, but the most likely cause is that the car with the most camber sits lowest (caused by sagged or lowered springs).
Check/compare the TCA angles when the cars are on a flat surface.

When I lowered 't Kreng many years ago it changed the camber from -0,5° to -2,0°.
It also changed the castor angle, lessening it by about 1°
The car handled fine in corners but was rather nervous in a straight line.

<center>Image
<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="3"><font color="red">My full Weblog</font id="red"></font id="size3"></b></u>[/url]</b></i></center>
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

Measured from the front wheel arches to the ground on both cars. They are almost identical.

Image[img][IMG]http://i615.photobucket.com/albums/tt234/nickmi/TR7%201975/Yellow.jpg[/img]
nick
'79 TR7 DHC
'76 TR7 FHC

Posted: 16 Oct 2013 18:32
by Beans
<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by nick</i>
[brMeasured from the front wheel arches to the ground ...<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
That only works if the wheel tyre combination is th esame on both cars.
Better to measure from wheel arch to axle line.

<center>Image
<font color="blue"><i>1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)</font id="blue">
<b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="3"><font color="red">My full Weblog</font id="red"></font id="size3"></b></u>[/url]</b></i></center>

Posted: 16 Oct 2013 18:41
by bmcecosse
As mentioned above -make/fit a strut brace - with a centre adjustment. Then you can crank that round to spread the turrets till the camber is as you want it.......

Image Image ImageImage

Posted: 22 Apr 2014 17:17
by nick
This is a follow up to my camber problem. I replaced the front springs in the '76 car and it appears that the negative camber problem is cured. Good call Beans. The new springs, TKC1329, are for AC equipped cars. They raised the front by about 1/2 inch. It doesn't sound like much but the effect on handling and appearance is quite noticeable. The straight line jitteriness is gone and the stance of the car looks remarkably better. It looked like the car was diving and the front wheels were noticeably cambered out. Not pretty.

At some point I will reinstall the AC. I hope that doesn't resurrect the problem.

Image[img][IMG]http://i615.photobucket.com/albums/tt234/nickmi/TR7%201975/Yellow.jpg[/img]
nick
'79 TR7 DHC
'76 TR7 FHC