Ride Height

[bpossel]

Hi All!

I removed the spring nuts (cheater) this morning that I mentioned on an earlier post.  Turns out there was only one of these cheaters, on the left side front spring.  Drove the car to let everything settle....

Note: I have replaced my rear upper spring pads; center rear mount; and have new bilstein shocks.

Here are my current measurements (from center of wheel cover star to lowest point on my fenders:

Left Front = 14.5 inches
Right Front = 15.5 inches[:0]
Left Rear = 14.25 inches
Right Rear = 14.5 inches

Before I do anything else, any suggestions on next steps to try and reduce the height of the right front by 1 inch?  Do I adjust the spring cup on the left rear?

  Thanks for your comments!
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[A Dalton]

You can just take the Mother-In-Law for a Ballast ride when using the car..Pleasure Cruise..
 Your front lean is typical driver side spring fatique from many miles of driver only weight.  That is why they had the spring helper on that side.
 Many cures , from spring change to J Villers O rings/spacers.. Think you would be better getting the left back up to the right instead of lowering the right to even out with the worn left ..

[JimVillers]

This would be a good time to collect information about ride heights.
My 230SL, Koni adjustable in front, old Bilsteins in the rear, custom srpings in front, stock in rear:

Left Front = 13.25 inches
Right Front = 13.00 inches
Left Rear = 13.50 inches
Right Rear = 13.50 inches

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

Wheel axle C/L reference is being used here for comparison and it is a good measure tecnique as it cancels out tire sizings, but what you realy want to look at is the difference in measure between the front control arm pivot points in Curb condition.  This is the ideal heigth as it takes all other alignmnet geometrics into
consideration . The 113 spec here is 88mm , +5/-10, and the main concern for front axle lateral level should show no more than 5mm differential, r/l.  This is where the spring rubbers trim specs are employed.
 These specs effect turning geometrics and pivot specs , so they are a better reference for overall suspension handeling/performance.
 All these specs are in the Data section of BBB chassis alignment sector.

[J. Huber]

Using the star to fender technique, mine currently are:

LF -- 13.75 (read 13 3/4).
RF -- 13.75
LR -- 13.75
RR -- 13.75

Give or take a 16th of an inch since I was freehanding it. I was surprised at the evenness...

New Bilsteins, engine & subframe mounts. Original springs.

James
63 230SL

[JimVillers]

Arthur ... I am all for better.  What are the control arm pivot points at curb condition?  From the lower outside trunion to inside upper trunion pivots?  88mm is about 3.5 inches.  If that is measuring from the lower control arm to the floor, that would just measuring tire effect.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[norton]

I would think that the condition of sub frame and rear axel mounts would have a big effect on ride height :?:

Mike Halleck
Chesterfield Mi
71 280SL
68 250SL (parts car)
94 E320 Coupe

[A Dalton]

quote:Originally posted by norton

I would think that the condition of sub frame and rear axel mounts would have a big effect on ride height :?:

Mike Halleck
Chesterfield Mi
71 280SL
68 250SL (parts car)
94 E320 Coupe

 Most certainly.. any part that is worn enough to change the chassis geometics  has an effect on spec measures.

[A Dalton]

quote:Originally posted by JimVillers

Arthur ... I am all for better.  What are the control arm pivot points at curb condition?  From the lower outside trunion to inside upper trunion pivots?  88mm is about 3.5 inches.  If that is measuring from the lower control arm to the floor, that would just measuring tire effect.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

 Jim

  This one is a little tricky to explain  [ for me , not that it is  tricky  geometry] ..
I will try a comparison approach to a Right Triangle:
 The thing that is getting measured is the angle slope of the lower control arm. This is done not from the floor as reference , but from the trunion/knuckle bolt C/L .
  With the car on a level surface:  Imagine a line going from the c/l
of the left trun/knuckle bolt [that goes through the lower control arm] going over to the right trun bolt c/l... so, this line is connecting the two bolts c/l.. right to left sides , full width of the front end...OK?

 Now , the inner pivot of the same control arms [ that is bolted to the cross sub frame] is the measure point . If one measures down from that control arm inner pivot point c/l down to the imaginary line , the distance should be spec for that chassis [ according to Benz Data]
 So , you can see that each sides measure forms a right triangle,
 with the spec measure being the height side of the right triangle
[ side A]..the  hypotenuse being the control arm. { side C ]
If both sides [ right/left]have the same spec at this measure , then you know the slope angle of the control arms are the same and the suspension is in spec. Changing spring, rubber , ect changes the control arms slope/ , along with the hiegth of the measure spec.
I made a simple tool for this measure and I think it is here or over mercedesShop somewhere in the archieves with the others .. been a long time ...
 The trick here is to bounce the car a few times to let it settle out and load the car to your normal load .. It is all in the BBB somewhere , with specs for both curb and test load conditions..
 ..prob clear as mud .. I am sure someone with tech writing skills beyond mine could clean it up.

 PS.
Seeing that you have just done some experimenting with different springs and konis up front , I would certainly check this measure to see how it compares to a Factory 113 spec , just out of curiosity...

[JimVillers]

Arthur .... Let me try to simplify.  On a level floor, the difference between the height from the floor of the inner A-arm pivot center and the height from the floor of the outer A-arm pivot center is the difference in measure between the front control arm pivot points in Curb condition that is shown in the technical data manual.

Expressed another way, if I make a cardboard right angle triangle with the hypotenuse the length of the lower A-arm and the short side 3.5 inches, it should fit square (level) under the A-arm.


Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[Vince Canepa]

Actually I think Arthur has explained it fairly well.  Now that I look at it, this is the same way M-B spec'd out ride height on the later cars (116-123 etc) also.  I usually measure from the floor up to the center points of the pivots and subtract the measurements to get a reading.  The product of that calculation should be 88mm + or - 15 mm for the 113 chassis as Arthur points out.  Using my floor up method has been fairly accurate for me in the past.  Provided you are in this range, you should have no problem being able to get the alignment with spec.

Every spacer, mount, etc on the car affects this spec.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[A Dalton]

Yes , you guys have it .. I don't mention measure from the floor cuz my Barn had wooden floors , so I never had that luxury.  So , I made a tool that uses a right triangle as it base design.
 The main 2 considerations are that the distance is within spec and that each side is within 5 mm of the other .
 If measuring up from the floor , as long as the distance from the floor to the knuckle bolts c/l is the same on both sides , you are there .. [ assuming floor is level]..if not, a good trick is to use a few 9" or 12" flooring tiles under the offending/lower side until they are equal.
That takes the tire sizing/PSI out of the equation.
One will notice that Benz recommends lifting the bumper and taking one measure , then pushing down on bumper and taking another measure , devide by 2 to get the Mean.. but , you can get it settled with a few pumps and take one measure and get the same results.
The important part of this technique is that all the other measures come off the axle being in this position, so it is a very important consideration. When this is correct, the axle spindles are completely straight and parellel to the level line and only then is the camber added to the correct plane .. That is how the geometry design gets Correct.. Same as toe is set individually from chassis longtitude C/L , equal on each side of the line, rather than total measure.

 Fussy ?? , yes .. but that is why I love these cars.. you can turn a screw or bolt and see the change/results of your adjustment..."tweaking" is a very satisfying gig for guys like us.

[bpossel]

 :oops: With the discussion of height related to the control arms, does this mean that the king pin and the control arm outer upper and lower bushings also play a part?

In other words, I have replaced my right side king pin and outer (upper and lower) control arm bushings.  I have not done the left side.  Would this then be the cause of the right side being a bit higher than the left? :?:

Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[113gray]

My Star to fender lip measurements (John Olsen springs all around, new spring rubbers, 4 new stock Bilsteins) are: DSF, 14.5"; PSF, 14.75"; DSR, 15.5"; PSR, 15.75".     -JP- '66 230SL, 5-spd, Kinder.

[enochbell]

Just for the catalogue, and for my own interest, mine are 14" all except the DR which is 13.5".  Full tank of gas, all new rubber except rear subframe, new shocks (Bilstein, original springs.  Sounds like I have a lowrider, but hey, it's a California car...

Greg

'64 230sl, fully sorted out...ooops, spoke too soon

[A Dalton]

Originally posted by bpossel

 :oops: With the discussion of height related to the control arms, does this mean that the king pin and the control arm outer upper and lower bushings also play a part?

In other words, I have replaced my right side king pin and outer (upper and lower) control arm bushings.  I have not done the left side.  Would this then be the cause of the right side being a bit higher than the left? :?:

Bob

 While worn control arm pivot points will change the geometry slightly, I doubt you would see it in ride height difference.. lower left side on 113 is usually driver weight over the years ,, there is always a driver load .. on my car anyway ..

[JimVillers]

I adjusted the ride height of my car with a jack this afternoon to 8.5 inches on the outside pivot and 12 inches on the inside pivot.  That resulted in 14.75 inches from the center of the hubcap to the bottom of the fender.  The measurements were the same on both sides.  The appearance of my car looks high at that height.  

Arthur .... What are the specifications to set the rear?


Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

J
 I don't follow you in that you adjusted the heigth with a jack???

[JimVillers]

Arthur ...  I used a jack under the center of the sway bar to raise the car until I had the specified 3.5 inches difference between the height of the inner and outer control arm pivots.  It is really quite easy since the outer pivot stays at a constant height because the wheel is on the ground.  After getting the correct measurements from the control arm, I measured it from the hubcap center to the lowest part of the fender.

I use the hubcap method because is easy and should be reasonably accurate.  This procedure should be reproducible on any 113.  


Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

Oh, I see ..
 You just wanted to see where a fender/axle c/l would be in reference to a correct spec. ride heigth  control arm .  
 Don't forget , you are close to max at 3.5". The specs are from 78 to 93 mm with the +5/-10 allowed tol. included.. [ talking 3 to 3 2/3" approx.] You may want to do the allowable range for fender to c/l measure.

 I thought you were going to see if the new suspension mod you did was in spec. I would be interested in those results.

 Anyway , the rear is looking for 1 degree, 30min , +/- 30 min  in curb load , positive camber..
 You will note in the spec charts that curb and test loads do not vary  camber changes with the heavy rate springs [ in comparison to standard springs].. this is a good testiment as to why regular springs usually result in sagging ass ends on 113s...

[JimVillers]

Thanks Arthur ... I will set and measure hub to fender measurements for the 78 to 93mm differential measurements.

My front is currently too low at 13 inches (hub to fender) and I plan to raise it with the rubber spacers previously discussed.  When I was at Blacklick, I had a lot of stuff in the trunk and the car looked level.  With the trunk empty, the car looks very "aggressive" and drives superb.

I will probably aim at the lower end of the specification and then work on the rear.  I am not sure that I have anything that will accurately measure to a half of a degree so I was thinking about setting the side chrome strip level (may or may not work (I can measure level accurately)).  The rear has a visible positive camber so it may currently be close.  It has the stock springs with new rubber bushings.  

I'll let you know how the measurements turn out.


Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

J.
 There is a simple PVC homemade camber measure tool I listed somewhere in the Archieves..easy to make and will handily measure 30 min.  increments...It is just a wheel offset fixture w/plum bob, but very accurate [ as all plumb bobs are.. ]

[Vince Canepa]

Jim & Arthur - My 1969 Technical Data book shows the delta between the inner and outer pivots as 88mm plus/minus 15mm.  88-15=73 = about 2 7/8".  I think I have mentioned this before - I like zero or a little bit of negative camber at the rear to reduce oversteer.  I think this is even more important when you stiffen the front.  As the front is stiffened traction increases at the front, dialing out some of the understeer M-B designed in.  I think you need to balance that at the rear and reducing positive camber at the rear is an effective means to do so.  

As I think about this project I have come to a conclusion - since the rear height is harder to adjust without altering the camber it might be better to get the rear set and then adjust the front to the desired height (hopefully it will be in the vehicle level adjustment range).

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[A Dalton]

I can not find those specs anywhere in  my info.  All 042/043 specs I have are 88mm curb, +5/-10.
 On the rear  neg camber ,  it is easy to change toward neg equally on both sides by using less shims on the comp. spring..
The main concern on the rear is the spring rate of soft springs allows too much neg with load.

[Vince Canepa]

Arthur - I checked again.  In fact, all models 108, 113 (including the 230 & 250), 114/115, etc. share the same 15mm plus/minus spec in the 1969 Tech Data book.  I also found the same info in 40-0/8 of my Service Manual Passenger Cars Starting 1968.  However, the 1959-67 Service Manual shows +5/-10.  It appears they updated the spec over time.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex