Springs/dampers

[mark]

I am going to order my springs and dampers from dampertech this week.

Last time this subject was mentioned somebody listed the specs and order codes etc and i seem to remember somebody talking about spring rates and that heavier people should get stronger rear springs?

Can somebody in the know please advise me if this is correct and which to order as they are quite pricey :eek: and i want to make sure i get the correct ones

Im 16 stone if that does make a difference

Thanks

[NEroadster]

Mark, I bought mine from Dampetech to be honest I just rang up and asked for a set of dampers for the haynes roadster the guy knew exactly what I was talking about and despatched them that day.

[mark]

I will do the same then, thanks for the reply :)

[londonsean69]

Mark, I bought mine from Dampetech to be honest I just rang up and asked for a set of dampers for the haynes roadster the guy knew exactly what I was talking about and despatched them that day.

What did they cost?

[spud69]

I am going to order my springs and dampers from dampertech this week.

Last time this subject was mentioned somebody listed the specs and order codes etc and i seem to remember somebody talking about spring rates and that heavier people should get stronger rear springs?

Can somebody in the know please advise me if this is correct and which to order as they are quite pricey :eek: and i want to make sure i get the correct ones

Im 16 stone if that does make a difference

Thanks

Hi Mark,

I did the same and got mine from Dampertech, 350lbs front and 200lbs rear. The front on mine are perfect but next time i will be going for 250lbs springs for the rear, i'm also 16 stone and with a passenger the rear does compress a bit too much. I have had to wind the springs quite a way up to get my ride height and also stiffen up the dampers a fair bit.

I've wound up the springs since this pic but it does show how much rear compresses. Car still handles excellently though and it was pushed to the limit on these pics.

AndyH

[HandyAndy]

Spud, i,ve got 250lb springs for the rear of my car, if you want to try them to see if they achieve what you like in ride/handling just shout, easy to get them off at the mo ;)

cheers
andy

ps, great pics, i wonder who the lightweight is in the passenger seat ???

[spud69]

Spud, i,ve got 250lb springs for the rear of my car, if you want to try them to see if they achieve what you like in ride/handling just shout, easy to get them off at the mo ;)

cheers
andy

ps, great pics, i wonder who the lightweight is in the passenger seat ???

Cheers Andy,

I think next time it goes on the track i may give it a try, its only when its pushed to the limit you notice.

Thanks...AndyH

[mark]

Hi Mark,

I did the same and got mine from Dampertech, 350lbs front and 200lbs rear. The front on mine are perfect but next time i will be going for 250lbs springs for the rear, i'm also 16 stone and with a passenger the rear does compress a bit too much. I have had to wind the springs quite a way up to get my ride height and also stiffen up the dampers a fair bit.

I've wound up the springs since this pic but it does show how much rear compresses. Car still handles excellently though and it was pushed to the limit on these pics.

AndyH


I think i will go for the 250 rears then, looking at those pics it is very low on the limit :D

Also my bro is like me and you spud over six foot and 16+ stone and he will no doubt be coming along for the ride regularly when i get it finished.

Nice pics by the way, i drove an aston martin db9 around teesside autodrome
a few weeks back. I had the instructor shouting at me on the last lap :D i got up to 130 on the back straigt then braked very late! scared myself a little too :eek: its prob more fun and better suited to your car though as you know its a very tight track and the aston was like a bus compared to a roadster!

Thanks for the info mate

[AshG]

call dampertech and ask to speak to Dave. tell him Ash from CKC Mag pointed you in his direction and he should do u a good deal. say you need a haynes roadser setup and he will know what to send to you. it may be worth asking for the 250 rear springs as they ship by default with 200's

[dogwood]

I'm going to change to 250's on my rebuild.
I found it bottoms out quite easly, especialy 2 up.
Yea OK we are both lardy......:eek:

David

Anyone say we need 300's will get a slap!!!!:mad:

[mr henderson]

Springs cannot be define by rate alone, the unfitted length is also a big consideration. For suspension to work as well as it could, then both the rate and the length must be right.

[dogwood]

????
Explain, for dummies.:D

David

[mr henderson]

????
Explain, for dummies.:D

David


Let's take a simplified example.

vertical spring damper with 400lbs of weight on it.

If the spring is a 200lb spring, then it will compress by 2 inches. If it started at 10 inches long, it will now be 8 inches.

If, on the other hand, it was a 400lb spring, then it would only compress 1 inch. If it started at 10 inches it will now be 9 inches long.

What I am getting at is that the two factors, rate and length are interdependant, and should both be chosen carefully to get the correct ride height and rate. Of course the adjustable spring base can be used to change the ride height, but people should be wary of using up the available suspension travel to compensate for having springs of the wrong length.

[Land Locked]

I'm going to change to 250's on my rebuild.
I found it bottoms out quite easly, especialy 2 up.
Yea OK we are both lardy......:eek:

David

Anyone say we need 300's will get a slap!!!!:mad:

I'll probably need 300's ;)

That said, Mr Henderson makes a good point. If I understand it right then for two up each around the 100Kg mark 250's that are a wee bit longer should do the trick then.

[mark]

What did they cost?

I just spoke to Dave at dampertech and it cost £340 delivered

He said i will have them on friday :)

Cant wait to take the the square box out thats been moonlighting as springs and dampers for the last few months since i got my chassis rolling :D

[londonsean69]

I just spoke to Dave at dampertech and it cost £340 delivered

Good to know, cheers

[dogwood]

Sorry Mr H.
I'm struggling with this one...
Wouldn't a longer spring wound up to make it stiffer (i.e. shorter)
have the same effect as a heavier one?

I'm happy with the ride height.
It's the bottoming out on humps and bumps I want to stop.

Sorry if I'm being thick.....:rolleyes:

David

[mr henderson]

Sorry Mr H.
I'm struggling with this one...
Wouldn't a longer spring wound up to make it stiffer (i.e. shorter)
have the same effect as a heavier one?

I'm happy with the ride height.
It's the bottoming out on humps and bumps I want to stop.

Sorry if I'm being thick.....:rolleyes:

David


The stiffness is set by the spring rate alone. The length of the spring controls the ride height. Let's ignore the adjustable spring platform for the time being.

Let's continue the example from before- vertical spring with 400lbs sitting on it. The bottom of the spring is fixed to the wheel, and the top to the chassis. Let's suppose that the desire ride height is 5 inches. Let's suppose that it is found that if the spring is compressed to 8 inches then the ride height will be correct.

So the target is to get the spring length to 8 inches. If a 9 inch 400 lb spring is fitted then that will produce the correct height (in this example). If a 10 inch 200lb spring is fitted it will also produce the correct ride height (because it has been compressed by 400lbs, so it is compressed 2 inches).

Now the thing to consider is what hapens if some EXTRA load is imposed, suddenly, such as a bump in the road making the wheel want to go upwards. If that bump was to procude a force of 800lbs (extreme example to make the point), then the 400 lbs sppring would be compressed by 2 inches, but the 200lb spring would be compressed by 4 inches.

From that example we can see that the 400lb spring is indeed stiffer than the 200lb spring. If the ride height is changed using the adjuster then all that is changed is the ride height, the spring itself cannot be made stiffer. It won't even be made shorter, as the car will simply rise as the adjuster is wound upwards (until the shock runs out of travel).

The above example ignore the change in the corner weight that would happen on a car, in other words the weight on that corner would increase as the ajuster is wound up, but as both rear corners are being considered, that's ok.

It's a complicated subject, but the basic principles of springs are straightforward. Mike Capon, who contributes to locostbuilders from time to time, has written a spreadsheet that will enable the determination of the correct spring rate and length if one enters the variables such as the angles dimension and weights. Sorry, I don't have a link to it.

[spud69]

I just spoke to Dave at dampertech and it cost £340 delivered

He said i will have them on friday :)

Cant wait to take the the square box out thats been moonlighting as springs and dampers for the last few months since i got my chassis rolling :D

That's a very good price Mark, did you get Gaz or Protech for that price?

Just looked at my invoice and paid £458 delivered from ProtechShocks. Think i'll be going to Dampertech next time.

Also just looked at my SVA brake test and Axle 1 weight with driver is 272kg and Axle 2 weight with driver is 298kg so i think the 250 or 300lb/in springs would be more suitable.

AndyH

[mark]

That's a very good price Mark, did you get Gaz or Protech for that price?

Just looked at my invoice and paid £458 delivered from ProtechShocks. Think i'll be going to Dampertech next time.

Also just looked at my SVA brake test and Axle 1 weight with driver is 272kg and Axle 2 weight with driver is 298kg so i think the 250 or 300lb/in springs would be more suitable.

AndyH

They are GAZ ones and i went with the 250 rear springs

Ash said to mention his name from CKC and speak to Dave to tell him he should give me a good deal :D

Not sure if this had any reflection on the price, but i was pleased when he said 340 delivered :D it is a very good price.

He also said if i find the 250 rear springs a little too much, a set of 225 or 200lb springs are only £44 if i want to change them.

[AshG]

sounds like he did you a pretty good price. anything less than £100 per corner is not to be sniffed at to be honest.

anyone ordering them can feel free to use my name if it gets you some money off. im not sure if it actually does but its gotta be worth a try. dave is a very nice chap and knows how to look after his customers.

[dogwood]

The stiffness is set by the spring rate alone.

OK, thanks for that Mr H.
Now I got it, :D
I was thinking that winding the adjuster up made the spring stiffer.
But of course it just lifts the car up on the shox
Doh!!!:rolleyes:

So a longer spring would give me the same ride, but more suspension.
Assuming it's not the shock thats bottoming out !!

Cheers David

[mark]

sounds like he did you a pretty good price. anything less than £100 per corner is not to be sniffed at to be honest.

anyone ordering them can feel free to use my name if it gets you some money off. im not sure if it actually does but its gotta be worth a try. dave is a very nice chap and knows how to look after his customers.


Yeah it was a great price :D i was budgeting £400 +delivery to be honest

You are right about he Dave seemed a very nice bloke

Quick delivery times aswell

[teun]

I did see by rallydesign a set of 4 for the price from 247.00:rolleyes: can i use them for my roadster?

[ozzy1]

these are 12" front and 11.5" rear need to be 13".
dampertech quoted me 425gbp incl delivery last week!
i got mine from obp.co.uk for 386gbp plus del of 15gbp.

[teun]

Oke would be to nice:D problem are always the high shipping cost to Holland.