19 replies to this topic

[kikiturbo2]

so,
was at the technical museum today, taking some pics of their Mercedes Type S (with a blower..), from 1926, when I noticed something on it's front suspension..







There was this additional link almost paralel to the leaf spring. On the housing it said Shimex, and on one side part of it was cut open (the car was used as a demo on our university long time ago....) revelaling a fine threaded shaft used to adjust some sort of preload on a spring inside...






my theory is that this is some sort of preload for the leaf spring... anyone care to shed some light.. ?

cheers

vlado

Edited by kikiturbo2, 19 April 2010 - 19:38.

[Greg Locock]

More heat than light. My first thought was a crane simplex linkage, either way Mr Olley probably discusses it http://www.sae.org/i...c_pdfs/R206.pdf

It might have been some sort of anti shimmy damper.

[carlt]

maybe to stop wind up under braking ?

[SteveCanyon]

maybe to stop wind up under braking ?

My guess as well - similar looking gadgets are often used on leaf-spring cars to stop the rear flapping around under wheelspin ...... with varying degrees of success.

[cheapracer]

maybe to stop wind up under braking ?

+1.

[VAR1016]

My guess as well - similar looking gadgets are often used on leaf-spring cars to stop the rear flapping around under wheelspin ...... with varying degrees of success.

Yes, used (maybe still are) to be called "anti-tramp bars"

As an aside, 1930s Rolls-Royce Bentleys used to suffer from front axle "patter" This was cured by the addition of lead weights!

[Catalina Park]

+1.

+2

[Tony Matthews]

+2

+3

[cheapracer]

= 8.

[Terry Walker]

The lead weight trick was used in several cars in the 30s when fat tyres and beam axles proved incompatible - the dreaded shimmy. The lead weights were usually in the ends of the front bumper, and acted as - wait for it - mass dampers!

Nothing new under the sun.

Once halfway decent ifs appeared, the problem disappeared.

Edited by Terry Walker, 20 April 2010 - 13:30.

[OfficeLinebacker]

The lead weight trick was used in several cars in the 30s when fat tyres and beam axles proved incompatible - the dreaded shimmy. The lead weights were usually in the ends of the front bumper, and acted as - wait for it - mass dampers!

Nothing new under the sun.

Once halfway decent ifs appeared, the problem disappeared.

what about ands or buts?

[mariner]

Speaking of old cars and suspensions and shimmy etc. I was looking at the wonderful Deusenburg SJ on display at the Haynes Museum in the UK and noticed that it's friction front dampers were connected to the axle by flexible straps. I suppose they had some sort of retractors but as there is no linkage stiffness at all in the upward direction it was truly a rebound only damping set up. None of your 50% in bump etc. rules of thumb for them.

Mind you I could forgive a Duesenburg SJ almost anything they have such incredible style, what a way to boulevard cruise!!

[Tony Matthews]

what about ands or buts?

Don't forget the maybes...

[gruntguru]

Speaking of old cars and suspensions and shimmy etc. I was looking at the wonderful Deusenburg SJ on display at the Haynes Museum in the UK and noticed that it's friction front dampers were connected to the axle by flexible straps. I suppose they had some sort of retractors but as there is no linkage stiffness at all in the upward direction it was truly a rebound only damping set up. None of your 50% in bump etc. rules of thumb for them.

How did the dampers return after the first rebound? Did the driver stop the car and reset them for the next pot-hole?

Edited by gruntguru, 20 April 2010 - 23:35.

[Greg Locock]

Rover P6 had masses in the bumpers that were sued as tuned absorbers, they were adjusted on the assembly line. I've worked on a BMW and a Porsche that had bloody great lumps of cast iron in them that were untuned absorbers.

[VAR1016]

Speaking of old cars and suspensions and shimmy etc. I was looking at the wonderful Deusenburg SJ on display at the Haynes Museum in the UK and noticed that it's friction front dampers were connected to the axle by flexible straps. I suppose they had some sort of retractors but as there is no linkage stiffness at all in the upward direction it was truly a rebound only damping set up. None of your 50% in bump etc. rules of thumb for them.

Mind you I could forgive a Duesenburg SJ almost anything they have such incredible style, what a way to boulevard cruise!!

Off-topic: Duesenberg J and SJ models had another unusual damper arrangement in their straight-eight engines. Fixed to one of the crankshaft webs was a cylinder which was half-filled with mercury. I understand that this corrected a vibration "period"

[Greg Locock]

Off-topic: Duesenberg J and SJ models had another unusual damper arrangement in their straight-eight engines. Fixed to one of the crankshaft webs was a cylinder which was half-filled with mercury. I understand that this corrected a vibration "period"

Yup liquid filled dampers are often proposed, rather more rarely used. Other similar things are sand or lead shot in chassis tubes. And for torsional dampers there are free floating flywheels with some liquid in the casing. If you really want to get into crankshaft vibration there is a book by Kerr Wilson - 3 volumes, $1000, classic.

[Catalina Park]

If you really want to experience steering shimmy you should try driving a twin steer truck.
It just takes the right combination of tyre wear and road surface to turn an experienced truck driver into a blubbering mess.
In my truck I am currently getting occasional attacks of shimmy when I least expect it. The truck shakes so much my head is almost hitting the window and the steering wheel is getting pulled out of my hands.
If it happens on a nice wide straight bit of road (which it rarely ever does) you can take your hands off the wheel and watch it just flog about half a turn each way while the truck just keeps shaking its way up the road.
The only cure is to slow down until the shake goes away.

[Tony Matthews]

The only cure is to slow down until the shake goes away.

I find that holds true for most of life's little problems...

[thomaskomm]

Wonderful pictures was this the car type which drove the first Nürburgringrace 1927? I believe there was an photo on grid with the newer Mercedes SSK and than the older daimler, before the went together, this is an car absolutley different from the SSK. Thanks in advance! Thomas Yes, it is! I have looked at google yes this is the car before the fusion with Daimler and Benz 1926 this is an old Daimler!!!! All i take back it is the newer mercedes-benz from 1926 with SSK the pictures are so little i have found a better picture i have simply mistaken..... tough very beautiful pictures! I love it!!

Edited by thomaskomm, 25 April 2010 - 08:10.