why is pushrod suspension better than normal suspension?

[Lennie]

Forgot, When we got together with AVO for the project we, well I, asked the question, about heat sink on the dampers, They said and I quote 'if the paint on the dampers does not bubble it will be alright' and if it does you still have some way to go before there is a problem.

[Peter Carmichael]

I was probably responsible for starting the hot air on dampers rumour. I've since had a lecture from Guy at Nitron saying that he gets worried when they run dampers alongside a formula gearbox underneath the exhaust headers, but a bit of hot radiator air isn't an issue.

[dino ferrana]

The Jap driver had presumably had very little time in that car and very little time with IRS.

There isn't much set-up data around about the IRS yet?

Had he ever driven around Brands?

Was he any good?

Comparing that car with the people who have had loads of time at Brands with a very well known car is perhaps a little unfair?

[Lennie]

Dino you are right of course, in our world it is all a matter of opinions and one mans perfect car is another’s pig. The nice thing is though we do have the stopwatch which is a strong argument one way or another, although I do have a very thick book of 'driver excuses'. Funny enough our cars have never won a race but the drivers we run in them have won lot's, and our drivers have never lost a race but, there again, the cars have lost a few.

[dino ferrana]

Yes the stopwatch is a strong argument but:

 

If you put me in a very well set-up CSR260 and Barry Horne in a 1.6 Roadsport he would almost certainly beat me unless the track had lots of big straights!

 

Did the Japanese driver own the car or did it belong to CC? If not it is a very strong reason not to push it and bin it in a gravel trap likewise if it is his brand new car!

[neil.cavanagh]

in the original advantages someone said 'unsprung mass'...

 

is this really true? Surely all the rocker arms and push rods and 'stuff' are still unsprung mass? and these are in addition to the shock that both have...

Don't all bits between the wheel and the chassis mounting points for wishbones & shocks have to be conisdered as unsprung mass?

 

So I would suggest that the in-board set up has MORE unsprungs mass, albeit a fairly minimal amount..

[DanB]

The main advantage of pushrod suspension on a seven IMHO is that means (if it's done properly) that the suspension is no longer falling rate. The angle of the dampers is not only important due to the reduced damper travel, it's also important because of the angle changes during suspension travel. Basically, the further the wheel moves up, the flatter the spring gets, and the lower the effective spring rate becomes. This means that as the car rolls, the suspension on the outside front wheel becomes softer when of course what you really want it to do is get stiffer.

 

This can be avoided either by using inboard dampers and rocker arms (like the Sylva cars) or a pushrod set-up. The pushrod set-ups have other benefits over a rocker arm system but IMHO they're relatively minor.

 

Dan

[julians]

All this theory is all well and good. What we really need is two lap times from the same car on the same day with the same (very good) driver, one with the traditional caterham setup and one with the push rod installation.

 

Dont suppose anyone has this data do they?

[V7 SLR]

I'm intrigued by some of the reports of people installing the Freestyle inboard kit that they have found their steering effort to be reduced. Now I'm particularly interested in this as V7 has always suffered from the need for a huge steering effort from new. I've messed about with most things and put it down to the 22% rack simply requiring that much leverage, but if something about the Freestyle kit helps, then I'm interested.

 

Now, who wants to buy a PC or some PC parts? I need to sell some stuff to pay for it.

[Tight fart]

Should be able to tell you in 3 weeks

 

pics here

www.p1spot.com

[Dave Barrow]

You need to spend some time in one to really comment chelspeed had it right I think and one other who crucially stated pushrod especially the freestyle version delivers rising rate not falling rate (unlike CSR). It also has twice the travel 2-1 which directly effects the spring/damper the Freestyle pushrod is about leverage of travel at the contact with the road surface the the effect of both these facts end up with the damper being able to react much much quicker and efficiently.

 

Mentioned b4 a spring 'doesn't care on it's angle' quite true but how it reacts to the road through the car is totally different otherwise there would be no problem having them horizontal which would provide little or no damping. If the spring and damper is positioned in a poor way it will simply do what it can and the rest of the shock over a bump etc will be transferred through the car upsetting it the spring and damper can not do it's job horzontally the pushrod is the exact opposite.

 

I know I might be seen as biased but having used both methods even after Gary improved my old car with more travel on the dampers and better rated springs and adj arb so well set up! the two don't compare.

 

I'm sorry but those that say it's just fashion are clearly just jealous I care little for the look only for the results at £1500 it's cheap the car is so much more liveable on a day to day basis so much more composed and when you hit a pothole or bump with one wheel the other side is totally oblivious no shock is transferred thru and with no need for arb this helps also.

 

So many will upgrade the engine before the suspension how a car feels on the bends in and out of them surely is what the car is largely about a fat engine won't get you round that corner any faster a lower power and better suspension will.

 

Personally I could never go back and now facing my next 7 Pushrod is a definate priority regardless of the fact few in the pub have any idea of it's supposed status.

 

Ducking low

 

Dave B Superlight No.175 Freestyle superwide Pushrod SV rear and aerofoil mmmmmmmm!

[Lennie]

B11 Moy went to Snetterton after being converted to pushrod it maybe that he will be along to report and after speaking to Richard in France at the weekend he seems very pleased with the set up as well. It is very dangerous to say on the internet but I can only say we have not had one negative response from any pushrod customer.

As for price we actually earn very little on the pushrod set up, none if we were to price in development costs, anybody want 6 pair of dampers that will not fit any Seven let alone any other car. We wanted alloy dampers as standard with spherical joints and adjustable for stiffness, and, we think, it is good value compared to the adjustable Bilstein dampers sold by the factory, or even a Nitron set. You pays your monies and take your choice.

I will say though having driven only pushrod cars for a while I realise how spoilt I have become when going into a standard car.

I, like every body else, can’t wait to drive the factory car speaking to the guy’s from the factory over the weekend they can’t wait either to see how it goes.

Open invite to all we are at Silverstone come down and I can’t promise a go on the circuit, we have enough test drivers booked in already, good morning tight fart, luxemburger, Billy and Chris, but we will let you take it for a trip round the paddock to get a feel before we take you out on the track.

 

[Nemesis]

for an independent view on the pushrod pick up circuit driver's review in 2003 (Oct or Nov)

 

Nemesis

Don't click here

[RiF]

Back at a computer at last!!!

 

Forgetting the theory here: On real roads I can drive happily at 30mph higher speeds (if I want to) on the same bit of road as I could a non push rod car 😬 Surfaces on many of the roads around where I drive in France are uneven although straight, the Freestyle pushrod system works and is NOT A FASHION STATEMENT. (Another doughnut you owe me Len )

 

For me when building a new car the price difference to wide track from CC with aero wishbones was very small and well worth every penny.

 

PS: Why does the new Caterham not have aero style wishbones????

 

Richard in France

Flying fast in my very bright yellow 226bhp Duratec 7, with internal kevlar/carbon panels and pushrod suspension 😬 😬 😬.for pictures of 7 and carbon

[CageyH]

Reading this, it seems Gambo took three years toinstall his system, but was moaning at me taking a long time

 

Only dead fish go with the flow....!

[TopQ1967]

Due to the design with pushrod and rockers you can alter the travel ratio of the damper.

For instance 1 inch suspension travel gives 1.5 inch shockabsorber travel.

The damping caracteristics of a damper can be preciser tuned over a longer travel.

 

Regards

 

 

Q.

 

 

 

 

[Mike Biddle]

Well now, I'm no race driver, though I do enjoy track days and sprints, and I can assure you without any shadow of a doubt that Freestyles inboard set up has totally transformed my car for the better.

 

Ride quality, turn in, steering and handling are all significantly improved.

 

Woth every penny! In fact I would say it's underpriced.

[RiF]

Totally agree, still happy 4 years on 😬

 

RiF Driving one of the first Duratec 7, and building CA07BON for Henrietta 😬 😬 😬.for pictures of 7 and carbon andCA07BON

[Atinod]

I thought frankynuckles was back until I noticed the date

[I.Mupferit]

I do like mine as fitted to my SV. More in the spirit of a constructive observation and certainly not a criticism though, if you are contemplating going this route I would consider fitting slightly different bolts to those Gary provides where the pushrod pivots in the rocker.

 

One of mine broke earlier this year, leaving the pushrod (fortunately) jammed up into the rocker. Upon inspection, the threaded portion of the bolt starts where it passes through the edge of the spherical joint and is under a very high shear stress at this point. Furthermore it is a 12.8 spec which I feel makes it slightly too brittle for something in shear so I have sourced good quality longer bolts where the threaded portion starts approximately 1mm in from the outside edge of the rocker. The bolts are now 10.8 grade and I did have to shorten them so now they have about 2mm of thread protruding out of the new nyloc retaining nut.

 

I think it is unwise to use the shorter, more brittle bolts as they are always going to be weaker at the point where the thread starts which just happens to be where it is under a very high shear loading in this application.

 

As I said though, that is just a constructive observation from my own usage and in no way intended as a crticism of the system which I like enormously.

 

 

 

Brent

(aka Arfur Nayo)

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

 

 

 

 

 

Edited by - Brent Chiswick on 5 Dec 2007 20:38:20

[BBL]

Brent - Have you mentioned this to Gary? I assume you have... If so, what was his reply?

 

- Sean

[millsn]

Might be worth pointing out that if you do bend your pre '96 car, you open up the realms of changing to a new front end- it is daft not to. Rather than buying new wishbones the pushrod kit offsets the cost of the new wishbones, dampers etc as you are replacing them anyway.

That's my justification for spending more than I really need to. Let you know what they feel like when the car is back on the road sometime in 2008 I imagine.

[I.Mupferit]

Sean, yes I discussed it with Gary at the time and he said mine was the first failure he knew of so it may be I was just unlucky in having a dodgy bolt supplied.

 

It is one of those occasions where you don't know you have a problem until it happens if you see what I mean. I built the car and it didn't occurr to me at the time about the positioning of the thread in relation to the spherical joint at the end of the pushrod.

 

However being the type of person I am, I needed to find a reason for the failure in order to retain my confidence in the car so on investigation I discovered that the threaded portion of the bolt wasn't in the ideal location given the stress mode it is under. I should have seen the potential failure point at the time of the build and it has irked me ever since the failure that I didn't.

 

Now it may just be that the bolt was, indeed, faulty and a simple replacement would have ensured it never happened again but I am a 'belt & braces' sort of bloke and it just seemed sensible to try and improve on the standard design while I was at it. By speccing a slightly less brittle bolt with the threaded portion resited to a safer location it was an easy and effective modification. I obviously replaced all the bolts at the same time even though no others had failed.

 

Hindsight is a truly wonderful thing! 😬

 

Gary is a fantastic guy for whom I have enormous respect and in no way do I blame him for what happened. He designed a really good system with which I am very pleased but that doesn't mean to say you can't make detail improvements to it if the need arises.

 

I would very definitely recommend Gary's pushrod system but as I said in the earlier post, it would be a good idea to consider fitting slightly different bolts. You may never experience the same failure mode as on my car if you don't change them but it costs no more and certainly won't do any harm.

 

 

 

Brent

(aka Arfur Nayo)

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬

 

 

 

Edited by - Brent Chiswick on 5 Dec 2007 20:40:11

[BBL]

Thanks Brent. I hope to try out one of these Freestyle pushrod systems someday myself. Sometime soon, I hope!

 

- Sean

[I.Mupferit]

Do it, you won't regret it.

 

Brent

(aka Arfur Nayo)

 

2.3 DURATEC SV Reassuringly Expensive

R 417.39 😬