GT6 rear spring swap

[GreenV8Machine]

On my non roto mk3 I changed my tired old spring for a new one from fitchetts. I think they said it was the same as the 1500 spit one, so thats what I got. Now the spring was good for about a month but seems to be tired again. Its never needed a lowering block and has always been low. Now looking at tiggrr1s gt6 rear setup its great, nice and stiff, good ride height. He said the chap he bought it from said it was a vitesse, is this a straight swap?

[Clive]

Interesting.... I am assuming it is a newish swingspring "designed" for the vitesse. Canleys had these made, obviously stronger than the std spitfire ones. Not sure if anybody else sells them?
And yes, I would assume a straight swap, but worth asking before parting with the old hard-earned

[cook1e]

cliftyhanger wrote:

Interesting.... I am assuming it is a newish swingspring "designed" for the vitesse. Canleys had these made, obviously stronger than the std spitfire ones. Not sure if anybody else sells them?
And yes, I would assume a straight swap, but worth asking before parting with the old hard-earned

I thought the GT6 Spring is lighter than the Vitesse, has less leaves in Roto and Non Roto form so I'd expect a Vitesse swing spring to be heavier with more leaves too.  Standard GT6 MKIII swing spring rear spring has the same part number as a MKIV Spit TKC0478 so a spitfire one should be up to the job. I think MOSS Triumphtune still do an uprated and negative camber version of the spring for spitfire and GT6 which is likely to be more suitable than a Vitesse Spring.

[tiggrr1]

GT6_User_and_Abuser wrote:

On my non roto mk3 I changed my tired old spring for a new one from fitchetts. I think they said it was the same as the 1500 spit one, so thats what I got. Now the spring was good for about a month but seems to be tired again. Its never needed a lowering block and has always been low. Now looking at tiggrr1s gt6 rear setup its great, nice and stiff, good ride height. He said the chap he bought it from said it was a vitesse, is this a straight swap?

Phil mines a rotoflex backend and that spring is bloody stiff. I think it's made of concrete ;)

I was told it was from a vitesse but thats all I know.

I'd have to check how many leaves and dimensions etc, It's been in a couple of years now and I don't remember the details.

[GreenV8Machine]

bloody useless arent yer!

I want to take my GT on the ecosse next year, but the backs just so low!

[Clive]

I think that originally the GT6 and spitfire springs WERE different, the GT6 had a thicker lower leaf....And I doubt anybody makes them any more, but may be worth asking. I am not sure how Canleys achieve the extra "strength" for the saloon cars, maybe more camber on the spring?? I have had a little success by swapping leaves in a swingspring, so it has none of the short ones but extra longer ones. May be worth a play?

[Deleted User]

also depends on whether the car is long or short shaft  the springs are the same length but a different rating...  the spring for the long shaft being stiffer

[Slimboyfat]

cliftyhanger wrote:

I am not sure how Canleys achieve the extra "strength" for the saloon cars, maybe more camber on the spring?? ?

Canleys achieve it by using the correct spring!

FYI there are two swing spring springs.

159640 which is short shaft Spitfire MKIV

159654 which is long shaft MKIV, 1500, GT6 MKIII

In the flesh they look very similar, but in practice they are very different beasts. Use a 159640 on a GT6 and it would drag it's arse. Use a (proper) 159654 on a short shaft MKIV and it would sit high in the air.

We use 159640 on our early Spitfire swing spring conversions, and 159654 on Herald, and early Vitesse conversions. Using a 159654 on short shaft saloon conversions compensates for any extra weight.

As far as I'm aware we currently have the only supply on correctly specified 159654 (and it's been that way for a while).

The market is currently awash with cheap and cheerful repro springs, but fortunately they haven't tried to copy the 159654. However there are at least 3 repro 159640 springs out there, that's why the price has tumbled on them in comparison to all other types of small chassis rear springs. One of the repro 159640 in particular is rubbish. We bought a small batch of them to evaluate based on the fact that we would no longer be able to compete with everyone else's retails. Joe fitted one to his Vitesse and we watched it droop ever lower on it's way around the recent Auto Ecose. It's to the point now where it needs replacing with a 159654, and it only did one event!

Beware anyone selling 159640HD, or anyone telling you there's only one type of spring that fit's swing spring car's because patently that's not correct.

[Tim Bancroft]

MY GT6 still runs its old spring, it was de-cambered back in about 1990 by TT, still does the job. The little car handles well for something that has a iron lump up front!

[CharlieB]

Slimboyfat wrote:

FYI there are two swing spring springs.

159640 which is short shaft Spitfire MKIV

159654 which is long shaft MKIV, 1500, GT6 MKIII

Beware anyone selling 159640HD....

My Spit 1500 parts catalogue (feb '81) lists 159640 ?

What's the 159640HD all about?

[herald948]

Where does p/n 311539 fit into the grand scheme of things, Dave? That's what comes up when dialing either original part number in at The Roadster Factory (USA) web site! Another US vendor (Spitbits) lists the 159640 for all swing-spring GT6 and Spitfire!

[Slimboyfat]

herald948 wrote:

Where does p/n 311539 fit into the grand scheme of things, Dave? That's what comes up when dialing either original part number in at The Roadster Factory (USA) web site! Another US vendor (Spitbits) lists the 159640 for all swing-spring GT6 and Spitfire!

The master price list (effective Sep 1974) lists 311539 as 'USE 156947'. 156947 is listed under a Spitfire peculiar code (FB).

I have found 311539 in the Spitfire MKIV Preliminary parts list, but I haven't got to hand the 'normal' MKIV parts list. As the part number was superseded sometime prior to Sep 1974 I presume there must have been a revision to the specification (maybe the long shaft introduction?), and 156947 was the result.

Checking 159640 the master lists it's application as a Spitfire peculiar part ('F' code), and lists 159654 as a GT6 peculiar part ('K' code).

From that it looks like when John Kipping settled on part numbers he used the GT6 number (159654) for all long shaft cars (makes sense), and the Spitfire number 159640 for the short shaft cars).

Thinking about it I remember all late MKIV's and Spitfire 1500's on their original British Spring manufactured 159640's looking very soft on the back end at a very early age.

Do we change our (CC) listings now to show 159654 as purely GT6 MKIII (swing spring), and 159640 as purely late MKIV/1500 as Triumph intended? Or do we stick with the way we have done it since JK realised a 159640 was to soft for a 1500, and that the only spring for a late GT6 MKIII was a 159654?

Bearing in mind I'm still seeing 1500's with new repro 159640's dragging their arses, and poor old GT6 MKIII's in an even worse state because they have been supplied incorrectly with a 159640 I think we will stick with what we have.
  

[Slimboyfat]

CharlieB wrote:

What's the 159640HD all about?

It's being sold as an 'uprated' 159650. It's effectively a 6 leaf version of a 159640 (normally 5 leaf).

We have one here. How you are supposed to get an extra leaf into the already tight confines of the pivot box I'll never know, it's defeated our best efforts.

[Slimboyfat]

timbancroft61 wrote:

MY GT6 still runs its old spring, it was de-cambered back in about 1990 by TT, still does the job. The little car handles well for something that has a iron lump up front!

Tim we are talking swing springs here, you have a rotoflex car.

[Paudman]

You may find this attachment interesting, it gives spring leaves and thicknesses.
I experimented recently with a number of springs including original GT6, Spitfire 1500 and late MK3 GT6 on my Mk1 Gt6 (note that the original spring was a massive 305 lbs!) but the best turned out to be an original MK3 swing spring bought NOS from Chic Doig, it has transformed the rear of the car and the exhaust no longer hits the ground at speed on bumpy roads...

[Rui Guimaraes]

I have a GT6 Mk1 and my current setup is the standard spring  lowered 3/4 '' with a 7/8 '' anti roll bar in the front.
My goal was to convert it to a Late Mk3 rear swing spring type using a brand new 159640HD spring that i bought a few  months ago. After the previous posts my doubts are uge...

Anyone has tried this setup with success?

What is, in your opinion, the best setup for a GT6 mk1?

Thanks
Regards
Rui

[GT6 M]

To try and clear some confusion up, the late GT 6 spring  IS different to a Spitty one,
the bottom two leaves are thinner,  but still same lenght,


you could make it stiffer by taking some of the shorter leaves oot,and doubling up on the bigger ones,

I put an extra leafin between the bottom two ones, [ spitty one,thinner ] this did make it stiffer, but lost the swing spring part, very little swing at all, see pick for thicknesses of leafs
middle leaf of the bottom 3, is a spitty one

[TimW]

796 wrote:

To try and clear some confusion up, the late GT 6 spring  IS different to a Spitty one,
the bottom two leaves are thinner,  but still same lenght,


you could make it stiffer by taking some of the shorter leaves oot,and doubling up on the bigger ones,

I put an extra leafin between the bottom two ones, [ spitty one,thinner ] this did make it stiffer, but lost the swing spring part, very little swing at all, see pick for thicknesses of leafs
middle leaf of the bottom 3, is a spitty one

WOW Marcus you do love your red paint!!  ;);D 8)

[Paudman]

1570 wrote:

I have a GT6 Mk1 and my current setup is the standard spring  lowered 3/4 '' with a 7/8 '' anti roll bar in the front.
My goal was to convert it to a Late Mk3 rear swing spring type using a brand new 159640HD spring that i bought a few  months ago. After the previous posts my doubts are uge...

Anyone has tried this setup with success?

What is, in your opinion, the best setup for a GT6 mk1?

Thanks
Regards
Rui

Yes, as I said in my earlier post, the ONLY spring that worked anyway well was the original MK3 Gt6 swing-spring. The others all fell short in some way or other.

[Jason]

Slimboyfat wrote:

One of the repro 159640 in particular is rubbish. We bought a small batch of them to evaluate based on the fact that we would no longer be able to compete with everyone else's retails. Joe fitted one to his Vitesse and we watched it droop ever lower on it's way around the recent Auto Ecose. It's to the point now where it needs replacing with a 159654, and it only did one event!

Ahhh that explains a lot, he did well to keep his exhaust with the lowrider Vitesse - it did look good though  8)

[tiggrr1]

339 wrote:

WOW Marcus you do love your red paint!!  ;);D 8)

Beat me to it Tim ;D ;D ;D

[Royboy66]

1570 wrote:

I have a GT6 Mk1 and my current setup is the standard spring  lowered 3/4 '' with a 7/8 '' anti roll bar in the front.
My goal was to convert it to a Late Mk3 rear swing spring type using a brand new 159640HD spring that i bought a few  months ago. After the previous posts my doubts are uge...

Anyone has tried this setup with success?

What is, in your opinion, the best setup for a GT6 mk1?

Thanks
Regards
Rui

Hi Rui,
my mk1 is currently running a swing spring with the longer driveshafts and thicker front anti roll bar.
I just went to fittchets (i live 5mins from them ;) ) and asked for a swingspring.  :-/

im not sure now what acual sprin I have, but it is quite low and thats without a lowering block!

Anyways, i like the way it looks and feels, and it doesnt cause any issues with grounding usually! even on tight hairpins ! ;D............

[tiggrr1]

(dance)(dance)(dance)And it went well round a we oulton park (dance)(dance)(dance)