rotoflex / non rotoflex - what's better?

[Deleted User]

448 wrote:

Thanks so much for all the replies. I'm a little surprised that such a popular car with (some would say.....I know....) a slightly dubious suspension setup hasn't got a recognized fix after all these (30+) years. Perhaps the problem isn't as great as the whispers would make you believe, but after such a long  time someone must have said 'to get a really well handling Spit/GT6 this is what needs to be done'. Or no?

Madaza - you have heard lots of positive comments hear - from people that know the cars well - what credentials do you have to keep perpetuating the "story" that there are problems with the suspension that "must" be fixed - a Troll perhaps ?  Is there a clue in your name ?

If the problem was as bad as you seem to keep trying to imply it is - and you appear to have no actual experience of these cars - then they would not be as popular as they are, and as you say, someone would have come up with a "fix".  Doesn't the fact that no "fix" is necessary tell you that there isn't a problem, and all your "whispers" are from people that have no idea what they are talking about.

If you can substantiate what you are saying, with names, and book/article references from credible sources then it would help, but to keep banging on the way you are is indicative of troll like behaviour.

[herald948]

I always love discussions about small-chassis Triumph rear suspensions...especially when someone quotes a friend of a friend who read some obscure article stating "OMG, you'll flip the car over just parking it..." or some such nonsense. Yes, pretty much any true swing-axle rear suspension will have its limitations in unique situations, such as sudden, repetitive transitions (think slaloms). Old VW Beetles (and Chevrolet Corvairs, and a few other notable cars over the years) all had swing axles but generally didn't have the "reputation" that the Triumphs got. Why? No clue! And no one ever seems to talk about how hideously dangerous those older 911 Porsches were (oh, at or well over the limit, right?). And let's not even talk about axle tramp in older Mustangs...or Opel GTs.... well, you get the point. As noted, pretty much every car ever made will have its "flaws" at some limit or extreme of use.

The GT6 was designed pretty much with the American market in mind and, as such, did have a rather soft suspension even in Roto-flex form. But they still handled pretty darned well. When I ran one as a daily driver in the mid-1970s, I was lucky enough to win my share of autocross (Solo II or whatever you wish to call it) events with mine, stock save for Koni shocks and 175/70R13 radials.

Oh, and I once took a Buick-owning neighbor in my GT6+ to pick up his car from the dealer where it was being serviced. My neighbor raved the whole 25-mile trip about what a nice-riding car my GT was! Same car. Well named, IMO: a Grand Touring car with some very sporting capabilities, all in a smooth (if tiny!) package at a decent price.

[Madaza]

Neil, thanks for that info. I suppose you are absolutely correct in that the best route is probably to just 'build' the car to what I want it to be. I suppose what I was trying to figure out was how difficult/convoluted  a task it was (and whether or not it really needs doing in the first place). Is the 1500 setup difficult to transplant?

Richard, yup need to drive a few and see how they feel, and then see what (if anything) needs doing. Btw your Spitfire sounds fantastic!

Tim, all the way down in Kent unfortunately.

Kevin, thanks so much for your extremely helpful reply. I don't know how much spare time you have on your hands, but my life is full enough without sitting in front of a computer trying to bait people about the suspension setup of their classic cars. As regards my credentials, I stated at the very beginning I knew very little of these cars and was asking for advice - if I was already an expert I wouldn't need to be here! It's all very well saying that the problem doesn't exist - you may know that because you are familiar with Triumphs, but for those who aren't there is a perception (rightly or wrongly) that these cars are dynamically a little unstable - if you think I'm making this up go ask anyone who isn't familiar with Triumphs. In addition I never said the problem exists - I asked IF it did exist, and IF so, how to remedy it. In that regards, everybody has been extremely helpful, and generous with their time and advice (in fact, I was just mentioning to a friend earlier today what great people were on this site). Once again, thanks for your valuable input into this discussion - very helpful.

[Tim Bancroft]

CT will hopefully do a evening Track Day at Brands Hatch in June or July, if you can make it pop along and I am sure one or two Spit or GT6 people would take you around the track-good way to see that some of these cars can handle.

Otherwise pop along to a Kent area meeting, sure someone would take you out in a car.

Whatever you do, make sure that you go for a drive in one of these little cars before steping into the market.

Keep asking the questions.

[Madaza]

Thanks Tim - I'll def try to get to a local meet and have a chat with everyone. Trouble is I've seen a lovely GT6 for sale and I'm getting itchy feet........ :)

[Deleted User]

448 wrote:

Trouble is I've seen a lovely GT6 for sale and I'm getting itchy feet........ :)

Then scratch the itch - go and buy it - you know you want to !

[thescrapman]

448 wrote:

Thanks so much for all the replies. I'm a little surprised that such a popular car with (some would say.....I know....) a slightly dubious suspension setup hasn't got a recognized fix after all these (30+) years. Perhaps the problem isn't as great as the whispers would make you believe, but after such a long  time someone must have said 'to get a really well handling Spit/GT6 this is what needs to be done'. Or no?

There was a fix (not that there really was a problem, just drivers who got caught out), in fact ther was 2.

The original engineering fix was rotoflex, the second was a financially motivated fix, that was swing spring.

Come to a meeting somewhere and we will give you some demonstrations.

Cheers

Colin

[herald948]

thescrapman wrote:

There was a fix (not that there really was a problem, just drivers who got caught out), in fact ther was 2.

The original engineering fix was rotoflex, the second was a financially motivated fix, that was swing spring.

Actually, the "original" original fix (albeit not a factory fix per se), dating back at least to the introduction of the Spitfire, was the camber compensator, a cheap, cheerful and very effective fix at that!

http://www.fairpoint.net/~herald948/database/cc/

[Madaza]

Cheers Colin, I'm out of town right now - returning tomorrow. As soon as I get back I'm going to try and figure out where the nearest/earliest meeting is.  :P

[junkuser]

Possibly the stories of bad behaviour of Spitfire rear ends dates back to the early ones which had 5.20 X 13 bias ply tyres on 4 inch rims.
When I first built mine up out of two sick ones in 1976 I used this specification and had replaced the rubbing blocks between the leaves of the rear spring which resulted in zero rear camber.

The first time I drove it around  a local right angle right turn at a speed I regularly drove a Thames 800 van the rear tucked under and the car turned through almost 180 degrees.
This violent oversteer would have been due to a combination of tuck and tyre roll.

Decided to find out more about tuning suspension and found a rather large book on the subject.  It was not very helpful but had a picture of an early Spit, taken from behind, as it braked into a corner on a race track.  The rear was up and the outside wheel tucked in.  The caption read - Early Spitfires had the worst road holding of any production car.
From this it seemed something should be changed.

Fitting 4 1/2 inch Zephyr rims on the Spit centres with 155 X 13 radials overcame the problem and when the rear spring settled to give a degree or two of negative camber vigorous cornering gave no problems.

I still drive this car and it has never given me a fright since.   All suspension parts are standard.

[JohnD]

Actually Madaza, I think that the reticence of your responders is down to innate politeness and British dislike of boasting.    There are fixes  - see any race involving 'small chassis' Triumph cars - but not many people like to to say, "Yes! I know how to fix it!   None of these other b*gg*rs do, but I'll tell you how I did it!"     There are some, but they are more likely to sell you than tell you, and they don't post here anymore.

On the other hand, why shouldn't they sell it?  EG: one of the greatest canards in motoring is that Porche 911s swap ends at the drop of a rain, er, drop.  But do Porche tell you how to stop your old car doing it?  No, they sell you the latest version, and continue to let on that it is death on wheels unless you are an expert, when in fact it is a well mannered sports car.  Makes you feel more of a hairy-chested he-man when you roll by your neighbour in his Volvo.
    Just the same, though Triumph aren't marketing it now - "Ho, yus! My GT6 has lethal cornering, but I can control it!"

John

[Madaza]

;D ;D Nice analogy John (esp appreciated by one who used to own said he-man car). I think I pretty much get the picture; there was a problem in the earlier cars but only in very specific dynamic circumstances, and has been very much hyped. Whatever 'issues' there might be at the limit can mostly be overcome by a range of fixes running the gamut from relatively cheap to bespoke custom setups. Right then , where's my cheque book.....?  :X

[Richard B]

Step this way Sir........   ;)

[rotoflex]

You should know ahead of time that the Spitfire & GT6 have differences of character beyond looks & handling, but differences of weather.  

The Spitfire is a fun, fun, reference open sportscar with air, wind, bugs, & the big outdoors being all yours.  

The GT6 is a small closed car which is fine if you like a tight, fun car, but also it can have a sort of tropical character all its own.

[Madaza]

I am easily led Richard.  ;D

rotoflex, by 'tropical' character I presume you mean it slow roasts the occupants...........?

[Deleted User]

448 wrote:

by 'tropical' character I presume you mean it slow roasts the occupants...........?

More Scandanavian - like a Sauna !

[Clive]

Back to "fixes" a used but good 1500 spring and front ARB should be £20-£50 depending on who is selling. Cheap enough! New about £150 I guess.

[Madaza]

cliftyhanger wrote:

Back to "fixes" a used but good 1500 spring and front ARB should be £20-£50 depending on who is selling. Cheap enough! New about £150 I guess.

Surely a 'no brainer' then?

[GT6 John]

Hello Madaza.  I have a Mk1 GT6 with the 'death-trap' swing axle! ;)

As I think you've started to appreciate through members replys in this thread this is total nonsense.  It has its limitations of course, but slow in fast out is the way to hold it.  Also don't lift off through a corner.

It can be tail happy, especially on very wet days on sharp bends, but then drive accordingly and you're fine.

There are easy things to improve the road holding capabilities that aren't expensive. They don't make a massive change, but it is definately noticeable.  I have done and can recommend the following on a Mk1 GT6:

Koni or Avo shocks front and rear set to a slightly harder setting than standard ones.

440lb or 480lb front springs, preferably 1" shorter than standard. You will have to cut off the inside lip of the wheel arch otherwise it will cut into the tyres on bends and rough roads if you fit wider tyres, which I have also found an excellent upgrade,

One degree negative camber on the front.

Decent quality 175/70/13 tyres. I've bored members of this forum rigid on just how impressed I was with the handling improvement on my GT6 by simply putting a decent set of tyres on. I fitted Uniroyal Rallye 680 rain tyres.

The GT6 is a bit tail happy in wet weather.  Fitting tyres that grip better in wet weather therefore makes sense!

Good luck with your purchase.  If you do go for a GT6, do post some pictures of it on here.

Oh, and yes, GT6s do get a tad warm inside at times! Lovely in the current weather we've been having.  Not so good in the summer.  But then that's why GT6 owners generally wear shorts and have wet backs!  At any meeting you go to you'll always spot the GT6 owners! ;D

[Madaza]

Thanks John, that's the kind of advice (along with others here) that I'm printing off and saving for when I get my car. Off to go invest in a Nike 'permadry' fabric suit.....

Edited to add; it always surprises me how few people pay attention to their tyres. I've owned cars where tyre choice was absolutely critical to handling, varying even throughout the temp extremes of the seasons. Should be the first place to look when attempting to modify the feel of a car.