front suspension travel Options

[Jeroen]

so, I'm test fitting my front wheels to check clearances etc.

I lowered the front end to where the a-arms are parallel to the floor
that's pretty freakin' low (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)

it leaves about 6" of clearance from the bottom of the long to the floor (got no jack donuts to measure)
and there's just a tad over 2" (55mm) of clearance before the top of the tire hits the inner fender

The original plan was to raise the spindles on my struts, but that would make the car even lower (if I keep the a-arm parallel)

so what's the deal?
is the "a-arm parallel" setting too low?
I thought that was the preferred setting to maintain optimal suspension geometrie (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

these settings all sound cool reading about them on the net, but the real world makes it seem quite a bit too much

any input????

(IMG:http://www.914world.com/bbs2/uploads/blog-1132592777.jpg)

[Aaron Cox]

what is diameter of your tires?

my car is LOW with 225/50 and 205/50 on 15" wheels. id say 4-5" at donuts...
a arms are parallel and not much travel.....

really needs raised steering arms for bumpsteer, as its still apparent even with the rack spacers

[J P Stein]

A lot of guys run them lower, but I ain't one of them.
Much depends on tire diameter, also. By raising the strut,
you can leave it at that height and get more suspension travel....I often find myself fresh out of the latter.
With a 22 inch tire, I have about 5.5 in of clearance from where you state. I have some raised spindles to go on this winter and plan to do just that.

AaARON:
A local guru has told me that joggling the steering arm is not so good. It screws up the Ackerman, says he.....tho that ain't what he said last time we spoke.
So I'm stuck with Elephant or ERP tie rod extensions.....that doesn't thrill me......but Fordahl said the ERPs are OK....bit keep an eye on em'. I looked at the Elephant's & started scratching my haid. (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif)

[r_towle]

the lowest you can safely go is to the point that the a-arm hits the frame during commpression of the shock...

So...if you remove the torsion bar adjuster...jack up the front suspension till the a-arm hits the fram and set it about 1/4 inch higher than that....thats it...

I measured from top of rim, or centerline of rim to fenderlip...

Also, set your car with the front end about 1/4 in higher than the rear...

if your car is to low...you will see a shiny spot on top of the a-arm, and possibly a bent portion of the frame tab that sticks straight down...

Rich

[TimT]

You can also get the strut housing cut down, and the insert shortened to allow the car to be lower, and yet maintain the same suspension travel.

[Jeroen]

tire diameter is approx. 23"

raising the spindles would (theoretically) add some suspension travel in the shock, but it will lessen the space between the top of the tire and the inner fender as well as overall ground clearance

[J P Stein]

QUOTE (Jeroen @ Nov 22 2005, 06:33 PM)

tire diameter is approx. 23" raising the spindles would (theoretically) add some suspension travel in the shock, but it will lessen the space between the top of the tire and the inner fender as well as overall ground clearance

That's what the T bar adjuster is for. Think it thru.
Raise the spindle 3/4 in, the car drops 3/4 & closes up the
the tire clearance 3/4. Crank up the T bar adjuster 3/4....bingo.
Same ride height as you started with, same clearance, 3/4 more shock travel.

Tim: Not with Bilsteins.....possible, but not a good idea as it would eliminate some of the insert bearing surface & seal......but *if* you have a machine shop......

[Jeroen]

QUOTE (J P Stein @ Nov 23 2005, 03:43 AM)

That's what the T bar adjuster is for. Think it thru. Raise the spindle 3/4 in, the car drops 3/4 & closes up the the tire clearance 3/4. Crank up the T bar adjuster 3/4....bingo. Same ride height as you started with, same clearance, 3/4 more shock travel.

agreed... but then the a-arm wouldn't be parallel to the ground anymore (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

[J P Stein]

QUOTE (Jeroen @ Nov 22 2005, 06:56 PM)

QUOTE (J P Stein @ Nov 23 2005, 03:43 AM) That's what the T bar adjuster is for. Think it thru. Raise the spindle 3/4 in, the car drops 3/4 & closes up the the tire clearance 3/4. Crank up the T bar adjuster 3/4....bingo. Same ride height as you started with, same clearance, 3/4 more shock travel. agreed... but then the a-arm wouldn't be parallel to the ground anymore (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

Is this bad? I think not.

[Aaron Cox]

QUOTE (J P Stein @ Nov 22 2005, 08:17 PM)

QUOTE (Jeroen @ Nov 22 2005, 06:56 PM) QUOTE (J P Stein @ Nov 23 2005, 03:43 AM) That's what the T bar adjuster is for. Think it thru. Raise the spindle 3/4 in, the car drops 3/4 & closes up the the tire clearance 3/4. Crank up the T bar adjuster 3/4....bingo. Same ride height as you started with, same clearance, 3/4 more shock travel. agreed... but then the a-arm wouldn't be parallel to the ground anymore (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif) Is this bad? I think not.

stock geometry then... which is what your aiming for anyway right?
by raising the rack, and the pickup points, it MAINTAINS the stock geometry with lowered stance...

[flesburg]

With the a-arm parallel to the ground, you are too low.

The factory setting is to achieve a difference between the center of the torsion bar and the center of the hub. I do not have my books here with me, but it is in the range of a difference of something like 90 to 100 mm.

At this setting the ball joint end of the a-arm will be lower than the pivot point (the a-arm will angle down toward the ball joint).

You can lower it more, and I think I am at 110 to 120 mm, but my a-arms still slope down.

We have tried all kinds of settings on the track, and you can go too low and it will effect handling. That is why you can raise the spindles up to an inch 25mm to get the car lower and keep the a-arm settings closer to stock.

I am not an engineer and cannot explain why, but as the suspension compresses, you want the first part of the movement to move the ball joint away from the center of the car. It has something to do with camber changes under load. I have read several technical articles on the subject and they all make these points...

Just my opinion, but I would raise the torsion bar adjustment to close to factory settings, and then lower the car by raising the spindles....

[Jeroen]

ok, thanks all...

somehow, I got it stuck in my mind that the a-arms should be parallel to the ground (dunno why)

going over your posts, it hit me that that wouldn't make any sense, cause when the a-arms are horizontal, that's your max neg camber (compressing furter would push the camber back out again)

maybe I should just stop thinking about stuff like this at 04.00 in the morning (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

[maf914]

QUOTE (Jeroen @ Nov 23 2005, 05:08 AM)

going over your posts, it hit me that that wouldn't make any sense, cause when the a-arms are horizontal, that's your max neg camber (compressing furter would push the camber back out again)

Very good point. I would probably never have thought of that. (IMG:http://www.914world.com/bbs2/html/emoticons/rolleyes.gif)

[rhodyguy]

what is the relationship of the tierods to the ground. pointing up, down, parallel to the ground? the 90mm + or - 5mm from the cl of the adjuster to the cl of the hub will more than likely give you the "nose up stance". don't forget to factor in the weight of fuel, tank, front hood, bumper, fenders (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif), etc, when you're setting things up.

k

[Dave-O]

QUOTE (Jeroen @ Nov 23 2005, 07:08 AM)

going over your posts, it hit me that that wouldn't make any sense, cause when the a-arms are horizontal, that's your max neg camber (compressing furter would push the camber back out again)

Not quite, Maximum camber happens when the A-arm is perpendicular to the strut housing, which is not necessarily when the A-arm is parallel to the ground. If you set the A-arm parallel to the ground you still have some camber gain as the suspension compresses, but not as much as if the A-arms are angled down.

If you can't fiddle with the spindle height due to racing class rules...it seems that keeping the A-arm parallel to the ground is a good compromise.

Cheers! (IMG:http://www.914world.com/bbs2/html/emoticons/beer.gif)

[Britain Smith]

Here is the new Elephant Racing Bump Steer correction kit that I believe is a huge improvement over the ERP version. I was mentioning this to JP during the discussion of jogging the arms.

-Britain

(IMG:http://www.elephantracing.com/images/bumpsteer/bumpsteertransparent.gif)

(IMG:http://www.elephantracing.com/images/bumpsteer/bumpsteer.jpg)

(IMG:http://www.elephantracing.com/images/bumpsteer/installedendview.jpg)

[J P Stein]

The steering arm has a tapered hole for the ball joint. The Elephant jobbie doesn't
have a matching taper. Don't like that. The thingy looping around the end or the arm must have some purpose.......and usually I can spot a reason....or a good one. I think it's supposed to put the bolt in double shear, but I'm not sure it really does....the upper section is too thin......*I think*....it seems to still be a cantilevered connection...thus the haid scratching.

[maf914]

QUOTE (J P Stein @ Nov 23 2005, 12:08 PM)

The thingy looping around the end or the arm must have some purpose.......and usually I can spot a reason....or a good one. I think it's supposed to put the bolt in double shear, but I'm not sure it really does....the upper section is too thin......*I think*....it seems to still be a cantilevered connection...thus the haid scratching.

I was wondering the same thing. The upper end of the bolt that passes through the steering arm may be reinforced by the yoke, but the connection to the tie rod ball joint is still single shear. It looks like the yoke will assure the loads are concentrated just above the ball joint. (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

What it all means, I don't know. (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif)

[Jeroen]

for some reason, I don't like the Elephant bumpsteer kit (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

[J P Stein]

QUOTE (Jeroen @ Nov 23 2005, 01:46 PM)

for some reason, I don't like the Elephant bumpsteer kit (IMG:http://www.914world.com/bbs2/html/emoticons/idea.gif)

Yeah, me too. Can't put my finger on it exactly and I don't often go on "feelings", but the man says ERP is OK so that's the way I'll go.....besides the ERP is CHEEPER (IMG:http://www.914world.com/bbs2/html/emoticons/mueba.gif)

Keep at it Jeroen. I see progress....it's all one color, for instance and on wheels. Git er' done.