shocking question?
 

i have a bit of a Q to do with shocks and why we need to have this 1" extension instead of making the hole shock longer?

so 13"-9" + 1 would be replaced with 14"-10 (14"-9.5" is a std size)
this would open up the list of sutable makes and 4x gaz inc springs could be got for £247 thats £110 less

cant see any problems with the rear its the front as we would be looking at an extra half inch stroke witch could be a problem for the draglink/top ball joint

a half inch spacer at the bump stop should sort it?
what we think

Beats me why matey maybe just a marketing thing to cream more quids out of you...no doubt somebody will know why:rolleyes:

Hi Barry

This is how the extensions came about came about ( This is to the best of my knowledge )

After the book was written & Roadster Number 1 had been on some real life roads, it was found that the dampers tended to reach full extension on bumpy surfaces .... Just guessing here " Full Droop !!?? ".
Sorry, clueless when it comes to suspension terminology :confused: :o

Chris decided the best way to counter this problem would be to add a 1" extension to the top of the damper .... This way, the original active part of the damper would remain unchanged.

Purely guessing here, I would imagine that if longer dampers were fitted, the springs lengths & rates would need to be changed to allow for the longer active part of the damper.

Chris felt that it would be unfair to expect the average builder to start messing about with the suspension geometry .... So much easier to use an " Out of the box solution ".

The way I look at it is, both Dampertec & Protec supply the roadster shocks with a 1" extension to cater for the Roadster.
I am sure that if there was a better solution available, either company would advise accoringly ;)

Been fabricating & working on motors for year's & I will be the 1st one to admit .... I know diddly squat when it comes to suspension design & geometry :D

Hopefully there is some logic in there somewhere !!

well the load will not have changed so spring rate would be the same (seems people are useing diffrent rates any way.

i did ask the guy at dampertech over the phone and he could not tell me why we need the extension instead of a longer unit. he seemed to think it was due a clearence issue from frame and bodywork.

if we where to look at what the diffrence would be between a std fitment shock with the extension and one without but longer (next size up) what would we get.
eye to eye length would be the same open.
eye to eye length would be half inch shorter (bump stop could be ajusted possibly with a simple spacer)
extra half inch stroke at shock (could be an issue for movemet at drag link).
spring seats can be ajusted so if we use the same length spring we could ajust up the seat but this might reduce the amount of running ajustment or run out of ajustment so the other option would be to use a longer spring.

what we realy need to do is get mr gibbs himself to tel us why we have the extension in the first place and why we dont just use a longer unit ;)

The way I see it 14"-9.5" with the springs a touch harder would be equivalent.

Here you go Barry Straight from the horses mouth :)

Item 10 Here

I have spoken to Chris in great detail at some of the shows .... Bless his cotton socks, spent a lot of time trying to cram that info into my thick skull :D :D

I would use 14" open length dampers then as there is a cock up somewhere.......:D

here is a thort if orignaly the car was designed to run 13-9 no extension
then a 14-9.5 would still be in scope of the drag link as the orignal 13-9 would be half inch shorter fully closed position.

any one have a pic of the 1"extension type fitted with the ride hight set idealy with engine like a pinto or zetec fitted so we have an idea how far up the spring seats are set

If using a shock with an inch extension in the body fits then a 14" shock will fit no problem. I don't see any reason to use the more expensive option.;)

Does it not stand to reason that if the book says to use 'x' then every body goes and buys 'x' so when people do group buys and starting selling parts they just read the book and supply 'x' ?

Yep it does indeed and I never noticed the shock absorber thing as I have not built a roadster up to a rolling chassis. I built a chassis to make the bodywork and that was all i was interested in. If I had intended to build a car and then come across the inch extended dampers then I would have wanted to know why as it doesn't do anything for the damper other than make it longer.

have i opened a can or worms here :)

No I don't think so all you did was ask a question.
As for my excuse....I never realised about the extended shock thing as never went as far as that when I made a chassis so I too would have asked questions as to why.
:)

Its a very good question and one im not qualified to answer either but I would have thought that as long as the shocks fit and can travel through theyre entire range without any issues then that would be fine.
I think its a case of what mr talon says and everyone has just accepted that everyone else uses them so we should too.
I beleive and may be wrong but the extension was put in to raise the ride height and keep the shock in its best position and was probably done instead of buying a new set to try.
after it was found to work it was left like it.
If I were to buy shocks as your suggesting without having seen them on another car id try and get sale or return on them then fit to the car without springs to check the suspension will go through its range without any problems.
if you go ahead ket us know the result so we can all get cheaper shocks
Ray:)

Not a Roadster I grant you but this is one I made a good few years ago using Sierra donor parts. The shock is mounted in the same position as the Roadster, well more or less. The damper is 13" open length and the wishbones are flat oval tubing holding up Sierra uprights. It's been in my LCB archive for 6 or 7 years hence the LCB border..hahahahaha

How does this compare to the Roadster? anyone got a close up picture?

Nope, just a complex subject that is not easily understod by the average Joe builder ( Read me ).

I would imagine that most folk, I include myself here, want to buy the book, build the car to the book, get it on the road & drive the well ballanced car that the Roaster is ;)

Just want to enjoy the dream just like the other people who have completed their builds :cool:

Or me Ronnie........I can and do talk a lot of horsedump at times:D Just wanted to know why an extended shock is being used when a 14" job will still work and be cheaper to boot.:)

It would be interesting to know the in's and out's of the theory behind the Roadster suspension,as Ronnie says buy the book,build the car,drive the dream ;) .

i do hope its not one of thoes supplyer spec things again it realy is odd that all the normal locost bits just dont fit the roadster why is that
arm bushes, shocks blah blah blah its even real hard to find a sierra thease days.
its geting to be expensive idea this haynes roadster build. :rolleyes:

i think im going to set up my own cottage industry just making one wierd bit for the roadster :)

Of course you could always buy the 13" open 9" closed shocks and make your own extensions if your handy with a lathe.
the extensions could be made for a lot less than the difference in prices you quote.
bear in mind though that the shocks that you are comparing to are custom made and not off the shelf.
Ray:)

Funny how folk post a comment then it disappears........:D

Must have missed that one was someone being naughty lol
Ray:)

No it wasn't rude, naughty or even taking the piss that's why I thought it was funny the post vamooooshed...:rolleyes:

Surely this is development , this is people developing a very good idea and making it better, move back from the conspiracy theory and take the engineering development further.

Life is a conspiracy you know, we all live in a poota cos I've seen the "matrix":D

Had a day and a half away from the 'puter so i think its time to add my experience / thoughts.......:cool:

Springs are rated at whatever poundage / inch of travel irrespective at what state of compression they are in as long as they don't become fully compressed they will always react the same. So, 14" dampers with 9" springs will react the same as 13" dampers + 1" extension with 8" springs just with the 14" dampers you will have more travel. The length of the springs governs the ride height of the car thus screwing the ring nut up and down the damper adjusts the ride height of the car / corner weighting rather than adjusting the handling. Cheaper, 14" springs, will be fine with the correct length, 9", springs on.

From my own cars on the road the rear of the car is ideal with 14" damper + 8 /9" springs, whether 13" + 1" (8" spring) or 14" (9" spring), allowing plenty of adjustment for ride height. Car runs well on 4" front and 4 1/2" rear allowing enough clearance for most speed bumps. The front, however, with 13" + 1" with an 8" spring is at it's lowest setting for the front ride height at 4". Obviously when it comes to track time i would ideally like to lower the car as much as possible so next time i'm going for a 14" damper (for longer travel) with an 7 / 8" spring to give the lower ride height when required. The rear there is plenty of adjustment available.

Ideally, for the cost of springs, i think i'll go for a stiffer track set of springs and also the standard road going springs (350 front and 250 rear). They are easy to change and would make a big difference on the track.

Just my thoughts.....Andrew

so what spring rates you useing spud (my book says 350lb/200lb for std so i take thats for a pinto)

Matt at Procomp has a good section on his webby about shocks, Something I never realised that no two shocks ever seem to be the same so Matt dyno's them so you get matched pairs...clever stuff :cool:

http://www.procomp.co.uk/shockdyno.html

Hi Baz r where did you get a price for the off the shelf 14" gaz coilovers? I've been looking at different suppliers.
From what people have said It sounds like the top hat was just a fix for those who had already bought 13" coilovers therefore I'd love to buy some £110 cheaper.
Whats the normal advised spring rates for a BEC for I have a zx9r engine?
Also do we need longer springs with the 14" units?

Cheers chris

ok people im not a suspension expert or a shock supplyer so please please stop pm'ing me about shock supply and what spring rate is right for your car. when i have a solid quote and supplier im can let you know im not doing a group buy to find out when your car is finished the shocks are not quiet right! you can buy your own at your own risk
im just tring to find a better option that you might want to go for yourself
price was given for 4 std locost/westfield dampers and springs with a length and spring choice after speeking to the supplier it looks like the orignal pack options at £247+vat might be no good but a simular price could be available
buy picking standerd size shocks and springs .
also you can go buy them from anywhere and of almost any make not just gaz or protech (that was the real idea)
avo,spax and meny others could be used as it looks like thay all make the same sizes.

Hi Baz,

350lb on the front works fine with the car, pinto or whatever medium size engine, but i did find with 200lb springs on the rear it felt a bit loose. Always put 250lb on the rear now and it does feel a lot better balanced and firmer on the rear (of the car ;) )

Andrew

A Bike engined car will be a lot lighter so each wheel will have less weight acting on it to get things spotty dog ideally you need to know the weight of the finished car....Then it comes down to weight of driver/passenger etc.
Imagine a car corner weighted as it sits then some one as big a bloke as Lesg sits in the drivers seat...said car will be all to wonky so it needs corner weighting with the big fella sat in the drivers seat to get things all tickety boo so he can wazz about safely.


I'm not saying les is huge but his arms are bigger than my legs....:eek:

Thanks for the reply, might borrow the missus bathroom scales under each wheel and see what the front weighs. Think they will tell you the roadsters BMI as well. ;)
Didn't mean to nag earlier its just shocks seem to be a very complicated subject with many options and they're an expensive thing to buy incorrectly especially on a budget.

I suppose springs are pretty cheap though and it these we can play around with.

How does the weight of the car per wheel relate to the spring poundage?

Cheers Chris

ok had a chat with supplier this morning
4x 14-9.5 gaz with 4x any rate 8 or 9" springs would be £264.08+vat and 10 p&p (i make it £326.89)
kit quoted was cheaper as springs suppied are cheaper as thay are shorter and not in the same price bracket :( thay would have been happy to keep the kit same price as long as the all the bits where the same price
all shocks in that size in stock and guy seemed to think spring rates would be in stock in most rates

£328.29 all in to your door from rally design tried arm twisting for pack deal but no joy :rolleyes:
spring prices step up at 8" :mad: and im thinking would be the shortest we can go
would be £37 less than extension type i was quoted :rolleyes:

so would you agree that 4x 14-9.5" with 8"front and 9"rear springs would be an ideal package for all round use andrew? or anyone else?
would realy like the springs set mid way for normal use idealy :)

Yes Baz, that's what i'll be going for on the Mx-5 car.

Andrew

Thing is if the suspension works at 4" ride height then lowering the car may well upset the handling. Just because it's lower doesn't really mean the geometry is right for it all to work.
Maybe the only way to run the car lower would be to lift the mounting points so the chassis sits lower, suspension is a minefield and one change can alter other things.

Here's a question:
Those that have got built Roadster, when the car is jacked up at the front how do the front wheels sit?..do they go into positive camber or negative? This one thing will show whether things are ideal or not.

It's nice to have the option to lower the car though, main thing on the track for me is the body roll, although not much, so getting the C of G as low as possible will help with this. When the car is lowered the wheels go into a negative camber, again not much though when lowering the car by 1 to 2", but this will help to keep the tyres flat to the tarmac especially with warm sticky tyres and cornering on the limit.

Be nice to try, that's all Mark. Wish it was spring to get out there again, going stir crazy stuck in here all day listening to Planet Rock and Radio 2. Definitely need some adrenalin rushes to put the fire back in the veins......

Spoke to TeamTrain yesterday and the car will be ready for track testing mid-march with the first race, hopefully, at Knockhill for a full shakedown then first round of the Northern Race Series at Croft on Easter Weekend. Going up on Saturday to check on progress and get some more pics. Roll on Spring.....:(

Andrew

Hi Andrew,

Will you supply 4x 14-9.5 dampers and 8/9" springs for mx-5 builders like myself? :D

Cheers

Chris