[Top] [All Lists]

Re: rear suspension geometry

To: "Harlan Jillson" <>,
Subject: Re: rear suspension geometry
From: "teds" <>
Date: Sat, 7 Aug 1999 17:21:10 -0700
Harlan, thanks for your detailed reply. I understand what you mean about the
tube shock/spring rebound rate. I wonder however that since the shock(s)
were not really designed to operate in this plane, (but were meant to be
strictly vertical), if they wear out much quicker due to the more intense
side or top loading. (more side mechanical wear).

I was thinking this was the case, also with various types of terrain the
rear suspension (with tube shocks), will act like there is no suspension at
all. I believe this occurs if the terrain has bumps that interfere time/wise
with the dampening actions of the shocks and the rebound of the springs,
such as in a series of 3-4 inch bumps in quick succession which individually
slowly taper off, like on a smooth slope.

when I travel over a series of these, (and at very slow speeds), (there is a
set unfortunately right in front of my house), the rear of the car and the
occupants are severely pounded, however  a pot hole or something like that
will not produce such a similar jaw jarring response.

I tend to suspect that returning the original shocks to the car would
actually be a good idea, perhaps the mad rush to 'improve' things British is
not warranted here. Would it be as simple as just obtaining a set of working
lever shocks ? I didn't put these in, the po did, but I do not see anything
special installed anywhere.

thanks, Ted Stowe
----- Original Message -----
From: Harlan Jillson <>
To: teds <>; MGList (E-mail) <>
Sent: Saturday, August 07, 1999 4:12 PM
Subject: Re: rear suspension geometry

> Ted,
>    In a word, yes.  Angling the shock forward does reduce its efficiency.
> The resistance of the dampner ( shock), which is used to dampen the
> oscillation of the springs during compression and rebound, is reduced by a
> factor related to the cosine of the angle from 90 degrees.
>   In the case of these shock conversions on B's,  most of the shocks used
> have far too much dampening for the spring rate and weight of the B, so
> reduction is probably an advantage,  the racers on the list could tell you
> lot more.
>    A lot of the stiffness in the suspension of the B is in the spring
> The front springs are running something like 480 pounds per inch of
> compression, and the rears are somewhere around 120 to 130 pounds per inch
>  this from books, not experience....).  The rear leaf springs also serve
> traction bars ( sort of ) to distribute the load to the body/frame.  The
> shocks/dampners are there to 'dampen' out the spring oscillation.  The
> stiffness of the shock relates to how fast this happens.  Another thing to
> remember is that most shocks resist compression and extension at different
> rates.   So a real stiff shock will feel make the suspension feel hard,
> depending on the resistance to extension the rebound rate may not be bad.
> All of this relates to two things,  how it rides, and how well the tire
> maintain contact with the road.  Too little dampening and the car will
> bounce until the oscillation settles out, to much and it will ride like a
> gravel truck, and won't keep the tires in contact with the road.
>    If you read some of the reports some folks have made on these shock
> conversions, you will find they run the full gambit, most of the
> racing shocks ( spax, konis, etc) are way too stiff except and their
> settings, and the non-adjustables may be fine, depending on which shock is
> chosen.
>    All of this is what I've gleened from reading the material some of the
> more informed folks have put up on the web, and my own limited experiance.
> I'm currently doing a shock conversion, so if you like I'll let you know
> it turns out.
> Harlan.
> -----Original Message-----
> From: teds <>
> To: MGList (E-mail) <>
> Date: Friday, August 06, 1999 11:14 PM
> Subject: rear suspension geometry
> >a question on the rear shock replacement with tube shocks...
> >
> >my 77 mgb came with this done, I have some kind of Monroe shocks in the
> >rear.
> >however my car has a real stiff rear suspension, in looking at the
> direction
> >of travel of the shock, I'm wondering how this works as the shock itself
> >not sitting straight up and down but it is tilted forward, doesn't this
> make
> >the dampening action less efficient ?
> >
> >thanks, Ted
> >
> >

<Prev in Thread] Current Thread [Next in Thread>