Rear Springs - Page 3

Patrick · #41 25th April 2006, 20:07

I had a look at the studs the spring plates screw on to (had them off while measuring things up for coil overs) - it looks like a pretty straight forward chop and reweld - the weld bit is only straight forward if you know someone who knows what they are doing!

Stuart · #42 26th April 2006, 07:02

I hope i can give you weights after my SVA next week ill keep you posted.

MartinClan · #43 26th April 2006, 07:50

Quote:

Originally Posted by Stuart

I hope i can give you weights after my SVA next week ill keep you posted.

OK thanks Stuart - that would be very helpful. Good luck with the SVA!

Robin

mperman · #44 27th April 2006, 18:25

Ok, I've got some developments here, this is getting good now.
I have a final weight to ponder over, supplied from John (Warwick) on the OC forum. His weight, which is also probably the same as mine, is 1040kg, WOW that's 100kg more than my highest estimate. Still its the best data to go on with.
So, for those of you that followed my earlier rantings (and stayed awake) these are my final estimated values:
FRONT
MR = 0.55 (0.38 squared)
WR = 82.5lbs (300lb spring)
Freq = 1.33 cps

REAR
MR = 0.63
WR = 90lbs (220lb spring, freelength 8")
Freq = 1.24 cps (softer than front)

Now that's mine sorted out, but then its heavier and E36 based. For an E30, let me have the MR and desired Freq and I will do a quick calculation. Or better still if Robin would like to do his and get me to check it...

Cheers,
Martin

raasayphil · #45 6th June 2010, 16:17

Quote:

Originally Posted by peterux

Hi Robin,
I've checked the part number of my Apex Springs.

They are marked 20-10352 HA 219/03

I also re-checked their current compressed length and it is 170mm. As I said, that is with no bodywork, petrol, driver or passenger.

By the way, the centre of my top bump stop "bolt" is directly in line with the outer edge of the rear box section that takes the rear bumper, when viewed from the back of the car.

hope this helps,

Peter

Hi I am finally getting into gear and starting my build and have the same problem regarding alignment of bump stops. Do I understand correctly that when the bumpstops are correctly positioned the alignment is as you describe?

Thanks

Phil

MartinClan · #46 6th June 2010, 17:21

There were some chassis produced with poorly positioned "posts" (ie big threaded stud) for the top spring plate. Mine was one of them. That would have been about 5 years ago.

I solved the problem by removing the lower spring plates from the lower suspension arm and having them welded back on so that the bump stops aligned. It was pretty easy to do - just 3 spot welds as I remember. Others moved the posts to the correct position but they are difficult to get to (specially if your car is part built) so I avoided that. Patrick circumvented the problem by using coil overs!

They weren't far out - about 1/2" - but enough so that the bump stops didn't line up. At the time Mark said that it didn't matter - I'm afraid I don't agree....

Robin

Stuart · #47 6th June 2010, 17:23

I took the Sportster to Track developments near Castle Combe. I still have standard springs in the back and Marlin supplied on front coilovers. He recommended the following after doing corner weights and a lot of measurements of the vehicle.

quote:Hi Again Stuart

I have managed to get some more info. At last I have found the formula I needed. Before I was transposing from Metric units and getting conflicting results.

Your choice is :- for comfort go with 250 Front and 260 rear. This would still be stiffer than a family saloon.
For a more sporting set up try 280 Front and 300 rear.
end:

I am yet to source some full length rear springs at 260lbs if anyone has supplier would be apreciated.

Stuart

MartinClan · #48 6th June 2010, 17:27

I had mine made. Can't find the details now but there is a thread somewhere on this forum with the name of the company!

Robin

peterux · #49 6th June 2010, 21:13

Quote:

Originally Posted by MartinClan

There were some chassis produced with poorly positioned "posts" (ie big threaded stud) for the top spring plate. Mine was one of them. That would have been about 5 years ago.

I solved the problem by removing the lower spring plates from the lower suspension arm and having them welded back on so that the bump stops aligned. It was pretty easy to do - just 3 spot welds as I remember. Others moved the posts to the correct position but they are difficult to get to (specially if your car is part built) so I avoided that. Patrick circumvented the problem by using coil overs!

They weren't far out - about 1/2" - but enough so that the bump stops didn't line up. At the time Mark said that it didn't matter - I'm afraid I don't agree....

Robin

Mine seemed to be lined up Ok, but I think I remember somebody having their mounts re-welded by Marlin. But my memory may be playing tricks?
I think Robin's solution is the simplest.

There are some pictures on his website.

...peter

raasayphil · #50 7th June 2010, 06:45

Thanks for advice.

My problem with that solution is that i had my trailing arms powder coated so they would be badly damaged. I have emailed Marlin to see what they say.

I came across a comment about the actual trailing arm bushes and the correct way to fit them - no clear explanation but as far as I can establish the thick end are on the outside of the trailing arm. Looking at them installed it does not look that this is wrong?

Phil

peterux · #51 7th June 2010, 21:39

Quote:

Originally Posted by Stuart

I took the Sportster to Track developments near Castle Combe. I still have standard springs in the back and Marlin supplied on front coilovers. He recommended the following after doing corner weights and a lot of measurements of the vehicle.

quote:Hi Again Stuart

I have managed to get some more info. At last I have found the formula I needed. Before I was transposing from Metric units and getting conflicting results.

Your choice is :- for comfort go with 250 Front and 260 rear. This would still be stiffer than a family saloon.
For a more sporting set up try 280 Front and 300 rear.
end:
I am yet to source some full length rear springs at 260lbs if anyone has supplier would be apreciated.

Stuart

Hi Stuart,
did TD make any other recomendations or changes to your car?

Do you know what the final Camber, Caster, toe settings etc are set to?

Did it make much difference to your cars handling?

I've got Marlin supplied springs at the front and Apex lowering springs at the back, but no idea what spring rates they are?

thanks

Peter

Patrick · #52 8th June 2010, 09:54

Quote:

Originally Posted by raasayphil

Thanks for advice.

My problem with that solution is that i had my trailing arms powder coated so they would be badly damaged. I have emailed Marlin to see what they say.

I came across a comment about the actual trailing arm bushes and the correct way to fit them - no clear explanation but as far as I can establish the thick end are on the outside of the trailing arm. Looking at them installed it does not look that this is wrong?

Phil

Hi Phil,

These are the trailing arms as they came off the donor:

http://www.msportster.co.uk/data/stripping29.jpg

There are some pics of the arms installed here: http://www.msportster.co.uk/detail.asp?cat=7&offset=12

Stuart · #53 8th June 2010, 15:42

Quote:

Originally Posted by peterux

Hi Stuart,
did TD make any other recomendations or changes to your car?

Do you know what the final Camber, Caster, toe settings etc are set to?

Did it make much difference to your cars handling?

I've got Marlin supplied springs at the front and Apex lowering springs at the back, but no idea what spring rates they are?

thanks

Peter

Hi Peter

Camber 1.5 degree
Toe .5 degree in front and back
Caster 5 degrees

Added to this corner weights were adjusted all together this made the car completely different drives much better now only issue I still have is its a little on the hard side so looking for new springs.

Stuart

GreatOldOne · #54 8th June 2010, 17:02

Thanks Stuart - one question though - how do you set up the camber on the rear wheels? I don't recall seeing any adjusters on the trailing arms.

Patrick · #55 8th June 2010, 17:21

you can't set anything on the back unless you get ecentric bushes which are quite pricey.

Stuart · #56 8th June 2010, 17:33

Correct Patrick you need ecentric bushes which I dont have but he did check the rears and that is what they were as standard.

peterux · #57 8th June 2010, 21:07

Quote:

Originally Posted by Stuart

Hi Peter

Camber 1.5 degree
Toe .5 degree in front and back
Caster 5 degrees

Added to this corner weights were adjusted all together this made the car completely different drives much better now only issue I still have is its a little on the hard side so looking for new springs.

Stuart

Thanks, Stuart.

For the caster setting of 5 degrees, how many washers front and back is that equivalent to?

Did they make any comment about the rubber bushes at the front or do you already have poly ones?

I'd like to get mine corner weighted as well sometime because i've read that this can make the biggest difference to handling.

...peter

peterux · #58 12th June 2010, 06:53

I checked with Apex and they tell me my rear springs (Apex 20-10352 HA ) are 51N/mm spring rate which according to an on-line converter equals 291 lb/in so between the 260 and 300 lb/in recomended by TD.

I'm not planning to change them, so this is just info for other builders.

...peter

Stuart · #59 12th June 2010, 08:08

Peter I have 2 washers front and back so equally spaced.
I have poly bushes on the front.
Your springs of 291 lb/in sound almost spot on but you must make sure you have different rate springs at the front otherwise you could get harmonics through the car.

peterux · #60 12th June 2010, 10:54

Quote:

Originally Posted by Stuart

Peter I have 2 washers front and back so equally spaced.
I have poly bushes on the front.
Your springs of 291 lb/in sound almost spot on but you must make sure you have different rate springs at the front otherwise you could get harmonics through the car.

Thanks for the info.

But I have no idea what springs Marlin supplied as standard when I bought the kit from them?