Rear spring rate

[TimW]

Anyone know what the spring rate of the leaf spring is on both rotoflex and swingspring?

[Anthony]

Don't know if it's accurate or not..........


http://www.teglerizer.com/triumphstuff/springs.htm

[Velocita Rosso]

339 wrote:

Anyone know what the spring rate of the leaf spring is on both rotoflex and swingspring?

I thought you were listening to your doctor.... ;)

Weve just bought two new springs for Spit/ and GT, we had two new ones on from Fitchetts, that we had fitted not so long back
Having problems , we rang Dave at Canley`s and he explained all the variations etc
Bought two new from him and the ride height raised, the material was thicker and they weighed another 2.5kgs more due to that.
Speak to David  

[TimW]

1903 wrote:

Don't know if it's accurate or not..........


http://www.teglerizer.com/triumphstuff/springs.htm

maybe i shouldn't be so lazy and looked my myself!  Thanks for the link!

[TimW]

michael_charlton wrote:

I thought you were listening to your doctor.... ;)

Weve just bought two new springs for Spit/ and GT, we had two new ones on from Fitchetts, that we had fitted not so long back
Having problems , we rang Dave at Canley`s and he explained all the variations etc
Bought two new from him and the ride height raised, the material was thicker and they weighed another 2.5kgs more due to that.
Speak to David  

Mike

What do the doctors know anyway!!

Us mere mortals don't get the opportunity to talk to Dave!!  I have called canleys but they said they didn't have any info to hand.  They did tell me to look it up in the workshop manual.  Why didn't i think of that!

[thescrapman]

michael_charlton wrote:

Weve just bought two new springs for Spit/ and GT,

Does that mean you have a new spring on the back of your spitfire now??

No more tyre shredding??

[Velocita Rosso]

thescrapman wrote:

Does that mean you have a new spring on the back of your spitfire now??

No more tyre shredding??

Cooee. The new spring was fitted two weeks before 10CR
The tyre shedding has now been solved by fitting adj radius arms
The four wheel alignment showed 9 deg toein on rear...so it should be solved
The rear wheel must have been scrubbing with the neg camber and toe in ...any way with new `Dutch` tyres and I can now clog it! ??)

Thread....so now the back end is lifted better due to better spring and the GT has improved tremendously
Tim ...PM Dave with the question  

[thescrapman]

michael_charlton wrote:

Cooee. The new spring was fitted two weeks before 10CR

Ah. You must have had too much crap in teh boot then.... :-)

[mikeyb]

michael_charlton wrote:

The four wheel alignment showed 9 deg toein on rear...so it should be solved
  

9 deg way too much for sure, but toe in would have caused your tyres to wear on the outside, thought your's wore on the inside?

[Nick Jones]

The outsides couldn't wear as they weren't touching the ground  ;)

So they just started scrubbing where they started touching - remarkably near the inside edge from the photos.  Good example of why low profile tyres and Triumph suspension doesn't really mix!

Should think it drives rather better too Mike?

Cheers

Nick

[Velocita Rosso]

Nick_Jones wrote:

The outsides couldn't wear as they weren't touching the ground  ;)

So they just started scrubbing where they started touching - remarkably near the inside edge from the photos.  Good example of why low profile tyres and Triumph suspension doesn't really mix!

Should think it drives rather better too Mike?

Cheers

Nick

Lot better
It would not drive in a straight line with symetrical tread and I had to fit assymetrical tread to achieve straight lines
Now all OK
Mike ...I thought the same until sat and thought about what someone said
Immagine a horizontal line(say a live axle), then place two full beer glasses on the end of the straight line sat acoss its axis
Then lift the beer glasses onto one edge so they tilt inwards then twist forward so the glasses are pointingback 15degs, then do an immaginery drive forward. See what I mean, and thats how the tread was wearing bad on the inside with a 9deg toe in and negative camber
So simple ...............and that was explained after the glasses were empty ;)

[starman]

339 wrote:

Anyone know what the spring rate of the leaf spring is on both rotoflex and swingspring?

Spring rate of the fixed spring used on the rotoflex GT6's is 185 lb/in.  The Spitfire swing spring vertical rate is ~320 lb/in.  These values are based on published specs, direct measurements and idealized calculations.  Supposedly the GT6 swing spring, p/n 159654, is stiffer than the Spitfire swing spring, p/n 159640, because its two bottom leaves are 0.3125 inch thickness vs. 0.25 inches for the Spitfire one, but I have yet to measure the rate of a GT6 swing spring that has such two thicker bottom leaves.

Note that these are semi-elliptical spring rates.  Half this rate is at work simultaneously at each spring eye.  Moreover, the wheel rate is the spring rate per wheel (i.e., half the semi-elliptical rate) times the motion ratio of the spring eye to that of the wheel squared, so the actual rate at the centerline of the wheel and tire, which is what matters because that's where the rubber meets the road and is a measure of true vehicle stiffness (not including the spring rate/compliance of tires), is less.

[TimW]

1416 wrote:

Spring rate of the fixed spring used on the rotoflex GT6's is 185 lb/in.  The Spitfire swing spring vertical rate is ~320 lb/in.  These values are based on published specs, direct measurements and idealized calculations.  Supposedly the GT6 swing spring, p/n 159654, is stiffer than the Spitfire swing spring, p/n 159640, because its two bottom leaves are 0.3125 inch thickness vs. 0.25 inches for the Spitfire one, but I have yet to measure the rate of a GT6 swing spring that has such two thicker bottom leaves.

Note that these are semi-elliptical spring rates.  Half this rate is at work simultaneously at each spring eye.  Moreover, the wheel rate is the spring rate per wheel (i.e., half the semi-elliptical rate) times the motion ratio of the spring eye to that of the wheel squared, so the actual rate at the centerline of the wheel and tire, which is what matters because that's where the rubber meets the road and is a measure of true vehicle stiffness (not including the spring rate/compliance of tires), is less.

Thanks Paul  very useful info.  :)