Rear shock angle ?

[cossie pop]

Hi all Im building a rear independent suspension set up for my pop have read most the techie bits but cant find anything on rear shock angle before they fold rather than compress is there an optimum angle they should be set at going to be using four adjustable coilovers was thinking of mounting through the rose joint bolts or just infront on the bottom wishbones any help appreciated as wont be long before I need to order them up
cheers Adie

http://i101.photobucket.com/albums/m58/KIPBITS/16012011476-1.jpg

[langysrodshop]

Shocks are designed to be used straight up Ade, They work properley that way, I can't remember the percentage difference but for every 5 degrees of lean the lose a certain percentage of efficiency, 20% if i remember right.

[cossie pop]

Cheers Steve diddnt realise you lose that much performance 10 degrees = 40%
better get the tape measure out ;) and come up with another plan
Adie

[langysrodshop]

I can't remember exactly Ade but its not good when you see people with 45 degree shocks as they ain't doing nought.



Cheers Steve diddnt realise you lose that much performance 10 degrees = 40%
better get the tape measure out ;) and come up with another plan
Adie

[Morris460]

It's the cosine of the angle of lean Ade. You can't just double it up for a doubled angle. Once you get beyond 45 degrees(70%) the value plummets rapidly.
As Steve said, more upright is best.

[Adam]

Why do you want to use 4 shocks for a pop with a cossie in it. Seems a lot of packaging & overkill. Be a lot simpler to use 2 coilovers at the correct rate for the car. You could probably get them straight up then with the more room you will have.

[cossie pop]

Hello Adam, I dont do simple :) definatly overkill but Ive got this look im after for the rear set up could of just bunged a jag under it and be done with it but thats to easy and to mainstream fancied something differnt ;)
Adie

[cossie pop]

I can't remember exactly Ade but its not good when you see people with 45 degree shocks as they ain't doing nought.


It's the cosine of the angle of lean Ade. You can't just double it up for a doubled angle. Once you get beyond 45 degrees(70%) the value plummets rapidly.
As Steve said, more upright is best.

Have come up with a solution and can get near upright if my guestimate is correct all depends on the average travel of the rear end ???
WHAT IS THR AVERAGE TRAVEL ON A EVERYDAY SET UP 3"????
been on the gaz site and found these
1 3/4" diameter bodies with 12mm rods
OPEN 9" CLOSED 7" TRAVEL 2"

OPEN 10" CLOSED 7 1/2" TRAVEL 2 1/2"

OPEN 11" CLOSED 8" TRAVEL 3"

OPEN 12" CLOSED 8 1/2" TRAVEL 3 1/2"
Gonna have a measure up in the morning got 4 pairs of coilovers stored up bet your bottom doller all will be to long
Adie

[nigelh]

I got mine from protech shocks.13 open with 9 inch springs. Andy made some solid bits to set the shock mounting points. They are set at 11 5/8 inches between the mounting points. It worked ok on his roadster.:)

[cossie pop]

I got mine from protech shocks.13 open with 9 inch springs. Andy made some solid bits to set the shock mounting points. They are set at 11 5/8 inches between the mounting points. It worked ok on his roadster.:)

Hello Nigel cheers for the input :) heard good reports on the protechs will buzz them tomorrow see what there prices are like.
Adie

[53pop]

hi adie see your getting the shocks under way as i said make up some metal stays to the length you need then you can sort out where you can fit them then sorce shocks to match or that are very close .then you wont where out them tapes B&Q will be putting them up soon as they will be one of there best sales.

[Happydaze]

Hello Adam, I dont do simple :) Adie

Suerely you should be looking at strut rods, bellcranks and shocks therefore where you want to put them. :cool: You can then tailor the bellcrank ratios to suit the shock travel seeing as how you've already got the shocks.

You've got a high tech type car so surely the right thing to do?

Only gas type shocks work at any angle, so i believe. Oil flilled types need to be upright (ish) - certainly not horizontal or inverted.

Chris

[Paul B]

There's more to it than simply being laid over. If it is compressed directly perpendicular to itself then the spring is exactly the same stiffness no matter what angle it is sitting.

Thus you can use a bell crank and have the shock sat horizontally, but beware the inevitable air bubbles in the oil that will louse up the damping effects, unless you use remote reservoirs.

[Brizey]

but beware the inevitable air bubbles in the oil that will louse up the damping effects, unless you use remote reservoirs.
I`m not that up on shock hydraulics, but surely there shouldn`t be any air in the shock to start with (as from new).
If there was, even normal road use would cause aeration (small bubbles) to permeate through the oil making the shock operate below it`s intended performance level, even if fitted at the correct mounting angle.
I`ve always understood a shocks oil chamber to be a fully filled (no air) sealed unit, or am I missing something :confused:...

[cossie pop]

Hi I did draw up a rough design with the shocks mounted behind the diff which was my initial idea but the bell crank side of it took it out of my capability at the moment as this is my first build and learning as I go along, trying not to creep above the floor level to much as want to keep the rear seat, Been onto gaz and they can supply shocks at £60 + vat each with rose jointed ends made to order in two weeks and there only 20 mins down the road from me
cheers all Adie

IF ANYONE HAS ANY LINKS TO BELL CRANK SET UPS COULD YOU POINT ME IN THE RIGHT DIRECTION :)

[Happydaze]

Based on what we've seen you achieve thus far it's a bit rich trying to play the rookie card :rolleyes: :p :D


Theoretically with bellcranks and pushrods you can place the springs pretty much anywhere you chose to.

Chris

[cossie pop]

Based on what we've seen you achieve thus far it's a bit rich trying to play the rookie card :rolleyes: :p :D


Theoretically with bellcranks and pushrods you can place the springs pretty much anywhere you chose to.

Chris

geee shucks cheers Chris
I think alot of it is I will always do my homework draw it out make cardboard cutouts and when I feel ive got it I will always have a go you never know till you try limited tools dont help but ingenuity comes in handy and of course advice from forum members
Adie

[Brizey]

Hi all Im building a rear independent suspension set up for my pop have read most the techie bits but cant find anything on rear shock angle
In answer to your original question Adie, it appears that 30 deg is considered the practical maximum angle (where effectiveness drops to 88 percent) and mounted as close to the wheels as practical...

[cossie pop]

In answer to your original question Adie, it appears that 30 deg is considered the practical maximum angle (where effectiveness drops to 88 percent) and mounted as close to the wheels as practical...

Cheers Brian that gives me a little bit of leway :)
Adie

[MisteR Tee]

That's what I understood it to be, had bell cranks & horizontal coil-overs in mine but have swapped them out for conventional location now. I'll try to find some pics but was difficult to see as they were buried up above the chassis under the boot floor.

Here ya go, found some. This is what I had, the bell-crank was operated by a complicated pair of links off the top of the hub carrier (just visible) & the other end of the shocks were mounted on the diff carrier mounting. One reason for changing them is just visible, the upper sections of the cranks were effectively U section & they were beginning to bend, you can just see the paint cracking & flaking!!! The bottom (horizontal) sections were tubular & covered in a thick layer of filler!:confused:


http://i1005.photobucket.com/albums/af176/mister26tee/My%20Model%20t%20coupe/PIC_2667-1.jpg


This is where they are now, the upper mount has now been braced & is fully welded front & back of the crossmember.;)


http://i1005.photobucket.com/albums/af176/mister26tee/My%20Model%20t%20coupe/IMG00322-20100320-1605.jpg

[langysrodshop]

The further they are from the wheel has an effect also Ade.



Cheers Brian that gives me a little bit of leway :)
Adie

[cossie pop]

Cheers Maurice and Steve :thanks:
the angle of the dangle is quit critical not just a case of finding two points to fit them to will have Alan round when it comes to fitment ideas

went back and found this which gave me the ideas of a bellcrank set up may be usefull for others

http://www.team321.com/321HotRodIRS/321HotRodIRShome.html

[cabby]

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http://www.team321.com/321HotRodIRS/images/StrutAnim.gif

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[MisteR Tee]

Not much work again then Tony??:D

[Paul B]

I`m not that up on shock hydraulics, but surely there shouldn`t be any air in the shock to start with (as from new)......

If it were so, the oil would leak out as it heats up and expands, I would think.

The few shockers I have messed with definitely have a squidgy/bubbley feel if you lay them on their side and operate them which, so I was told, is due to a small air pocket that inevitably gets trapped inside during manufacture.

If you then stand them up, pump them a few times, the bubbles work to the top and are clear of the damping/hole action.

[langysrodshop]

Correct Paul, thats why they shouldn't be laid over.



If it were so, the oil would leak out as it heats up and expands, I would think.

The few shockers I have messed with definitely have a squidgy/bubbley feel if you lay them on their side and operate them which, so I was told, is due to a small air pocket that inevitably gets trapped inside during manufacture.

If you then stand them up, pump them a few times, the bubbles work to the top and are clear of the damping/hole action.

[ross@rmrrestorations]

Anymore than 30 degrees and it's wise to get the shocks re-valved.
My cantilevered rears for my 34 lie almost horizontally and had to be re-valved accordingly.