Adjustable front suspension legs

Marsu · Postby **Marsu** » 26 Apr 2011 16:52

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by DNK

Marsu, the spring rates are on the springs in the pics
<hr height="1" noshade id="quote"></blockquote id="quote">

Thnx Don for pointing that out.

So version 2 of the front strut spring appears to be a 2&1/4" 8 coil 'RACING 250-60'. Beans, I'd be grateful if you could advise its free length, if known, and any relevant additional info, such as how this compared to version 1 which appears to have 10 coils.

The rear spring appears to be a 2&1/4" 8 coil 'RST 200 30-51'. Similarly, Beans, I'd be grateful if you could advise its free length, if known, and any relevant additional info.

Beans · Postby **Beans** » 26 Apr 2011 17:49

The details are indeed printed on the springs, but are metric, they are from AST Suspension.
â€¢ front; free length 250mm, rate 60kg/cm diameter 60mm;
â€¢ rear; free length 200mm, rate 30kg/cm, diameter 51mm (plus helper springs to keep the springs seated on full suspension drop;
Also bear in mind that the rears will be mounted just behind the rear axle, changing the effective spring rate considerably.

More info on these modifications in my weblog under the label â€œsuspensionâ€
And sorry, I wonâ€™t give advice on spring rates or ride height as that is very personal [;)]

As it stands now the rears will (hopefully ) be fitted somewhere in the next few weeks (in time for a short trip to Scotland).

As the forces on the dampers are bigger than those on the springs I have no short term modifications/strengthening in mind for the rear strut towers. But I will pay some extra attention to that area when I start on the bodywork (again hopefully) next year (probably seam welding and cross bracing).

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

john 215 · Postby **john 215** » 26 Apr 2011 19:20

Hi,

The picture below is off S+S front adjustable strut, actually one out of there shop, lots of sweaty hands been man handling it !

I feel the need for a set I am affraid [8D]

Has the advantage too of being able to use standard fit spings of any spring rate.

Cheers John

LIVE LIFE A QUARTER OF A MILE AT A TIME!
1979 3.5 FHC(STATUS PENDING!!)

1982 2.0 DHC NOW A 4.6,ON THE ROAD NOW KICKING AR5E !!!!

Jolyon39 · Postby **Jolyon39** » 26 Apr 2011 21:06

Can someone please explain the difference between these top mounts and the rubber filled TR7 and TR8 top mount?

I understand the bearing being added but wonder just what difference the removal of the rubber makes to the top mount. Would not the front become very stiff and transfer a lot of jarring and noise?

Jolyon

Beans · Postby **Beans** » 26 Apr 2011 21:17

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Jolyon39

... what difference the removal of the rubber makes to the top mount ... <hr height="1" noshade id="quote"></blockquote id="quote">
Gives much more precise steering and better feel of what's happening under the wheels.

And of course you'll have to ask yourself how you use the car.
There's a reason why my DHC has only slightly uprated suspension (200 lbs springs with Koni's and polybushes)

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

Vegas_M · Postby **Vegas_M** » 26 Apr 2011 23:41

Ok, given Beans springs settings:

front; free length 250mm, rate 60kg/cm diameter 60mm
rear; free length 200mm, rate 30kg/cm, diameter 51mm

In "Henglish" that converts to:

front; free length 9.84in, rate 336lb/in diameter 2.36in
rear; free length 7.87in, rate 168lb/in, diameter 2in

(1 lb/in = 0.01785 N/mm)

M.

Martin

[url="https://docs.google.com/leaf?id=0BxOL0HRH5pDeNWRlOTVhZjgtMWE1Mi00ZWNiLWE3ZGYtOWNiODU1Y2JjOGQ0&hl=en_GB"]My TR7v8 Document Repository[/url]

DNK · Postby **DNK** » 27 Apr 2011 04:13

9.84.? Boy that sounds long

Don
"No More Cars For You"
71 TR6- Perpetual remodel
80 TR7 V8 Kick in the pants

Last TR · Postby **Last TR** » 27 Apr 2011 04:46

They sound short to me. My nominally 1" lower front springs from TSI are about 12-3/4" free length. The front rides right at factory height. My old collapsed springs are 10-3/4" free; the front rode 3" low.

Ken
Anchorage, Alaska

1980 TR8, 1973 TR6, 1965 Volvo PV544, 1958 MGA, Jeep Cherokees

V8Wedgehead · Postby **V8Wedgehead** » 27 Apr 2011 11:21

A 10-inch long spring that is over 200lbs is right for the coil over front adjustable set up shown above. I have the Works Rally TR7V8 front Bilsteins and with the short inserts the spring used is 10-inches and you can raise or lower to adjust the height.

Michael
1980 TR8 FHC #0020 Rally Conversion

dycecooper · Postby **dycecooper** » 27 Apr 2011 13:31

I have the Bilsteins too and the rear arms with the lower spring seat.

DNK · Postby **DNK** » 27 Apr 2011 13:37

I stand corrected . I was going by old memory and i thought the number for the front was in the 8.5-9

Don
"No More Cars For You"
71 TR6- Perpetual remodel
80 TR7 V8 Kick in the pants

Vegas_M · Postby **Vegas_M** » 27 Apr 2011 14:11

Remember guys, ride height is affected by a number of things, the actual suspension geometry, the spring rate, it's free length and the preload on the spring. Given the same suspension geometry, it's really the latter three.

The spring rate is basically how much the spring compresses for a given load. e.g. 200lb spring compresses 1" for every 200 lb of load.

For ride height we only need to talk about static loads on the spring. Dynamic loads give me a headache....

A stock front strut has about 7" of gap from the lower spring mount to the underside of the upper mount at full extension.

So, a mounted 10" 200lb spring has 600lb of preload at rest (3" x 200lb/in). This means that it will not compress more until a load greater than 600lbs is applied. It will take another 200lb to compress it one inch.

A 12-3/4" 97lb spring (stock spring), will compress almost 5" to mount it, giving it around 500lb of preload (close enough for this chat). However, it will only take 100lb to compress it another inch. With this spring and 600lb of load, the car will sit 1" lower than the previous one. The car will also have a "softer" ride than with the 200lb spring.

With an adjustable spring perch, you are basically changing the amount of preload on the spring, which impacts the how much the spring will compress with the car at rest, which impacts the static ride height. The spring rate impacts how "stiff" the car feels when driving. Simple geometry.

M.

trekcarbonboy · Postby **trekcarbonboy** » 27 Apr 2011 16:04

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Beans

<hr height="1" noshade id="quote"></blockquote id="quote">
What type of metal is this sleeve made from? When I do a search all I can find is aluminum. You can't weld aluminum to steel right? Anyone in the US have a source for these?

Craig

Vegas_M · Postby **Vegas_M** » 27 Apr 2011 16:49

Almost all sleeves are aluminum. Get one with the correct ID for the strut tube diameter. Figure out where you want it to sit and weld a steel plate below to support it. With the spring load it isn't going to move. Just put a good coating of anti-seize on the inside of the sleeve before you mount it or you will get corrosion.

Some of the kits come with o-rings to take up the difference in tube diameters, but they will rot over time. Better to make a steel spacer out of some pipe, if need be.

M.

Martin

[url="https://docs.google.com/leaf?id=0BxOL0HRH5pDeNWRlOTVhZjgtMWE1Mi00ZWNiLWE3ZGYtOWNiODU1Y2JjOGQ0&hl=en_GB"]My TR7v8 Document Repository[/url]

Beans · Postby **Beans** » 27 Apr 2011 17:06

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Vegas_M

... rear; free length 7.87in, rate 168lb/in, diameter 2in ... <hr height="1" noshade id="quote"></blockquote id="quote">
And given the different position its effective spring rate is the same as a 240 lb/in spring in the standard position.

<center>

1980 TR7 DHC (my first car, now restored and back on the road)
1981 TR7 FHC Sprint (better known as 't Kreng)
[url="http://www.tr7beans.blogspot.com/"]My Weblog[/url]</center>

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Adjustable front suspension legs

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