new springs front axle

[Costin Moga]

I'm at the point of replacing the front axle springs. The old ones are resting on the rubber bumper leaving no room for spring travel. I think this was the original design ideea but my opinion it was a mistake. Basically the axle travels only downways performing a good axle twist but it does not levell any of the road bumps or stones leaving this at the mercy of the tire.

Seccondly, the lower main leaf is made of 3 parts having the eye tight on the upper main leaf. I think a classic military wrap eye and a continuous leaf will be better.

Has anyone on this forum performed such a change ? I would like to get some opinions.

I would do this at Owen Springs in the UK. They told me have done a pair of springs for Adam Servers. Can anyone get me in touch with him ?

[54ekstrom]

What car is this? If it is a "Sugga", the setup is a rubber bump stop that hits the main spring leaf between the axle and the front spring anchor; the rubber is touching the spring lightly even with vehicle unloaded and on level ground. I just removed the rubber stops to get better articulation and driving comfort. I guess some sort of soft stop i required, though, so if I had kept the car I would have had to make a modified stop.

[Costin Moga]

Yes, the car is a TP21.

After a dozen of emails and some phone chat this is what I came through - they can make a replacement spring (following my requirements) in any of these:

- as original but with 6.35 mm material thickness seccond leaf continuous

- as original with 7.9 mm material thickness seccond leaf continuous

- 5 cm lift spring, more arched giving a longer camber dimension (distance measured from line unifing center eyes end top of first leaf at its center) in both combinations (6.35 or 7.9 mm)

- can add an extra leaf if required

I think best option is to go for 5 cm lift, 6.35mm material and an extra leaf (which can be removed if necessary).

They have done for Adam Servers as orignal, 7.9 mm thickness. I was curious how these performed.

My concern is if going with 5 cm lift, the geometry of the spring would be too much altered.

Your opinion ?

[54ekstrom]

Well... my opinion cannot be other than very general, but here goes: Adding leaves or making them thicker will probably make the spring "harder". Given it has the same unladen shape as the original spring, the car will be higher, BUT the spring will be stiffer, resulting in harsher ride and limited articulation. I would probably go for a spring that has a "force factor" that is similar to the original, but has a more pronounced curvature when unladen, and I would make rubber stops that engage only after substantial compression of the spring (really just being bump stops). That would make for a bit more "comfort" and a slightly higher front. I am generally very cautious about altering the ride height of vehicles such as the TP21; the steering linkage and propeller shafts may be affected by angles not accounted for at the time of designing these parts.

[Glynn]

Hi Adam has a perkins engine in his which is heavier but it does work well off road  ,i can ask if he will contact you if you wish?

[Costin Moga]

please do so, I would like to have a quick chat with him and benefit from his experience

[Costin Moga]

I made a schematic drawing of the original spring and the +5cm one as it would be.

It's interesting to know the front axle moves some 30mm backwords when axle travels from full spring extension to full spring compression !

With a longer, more arched spring (+50mm camber) it would travel >46mm !

 

 

front spring.pdf

[Glynn]

Hi if you pm me your email i will pass it on to him

[Costin Moga]

mogacostin (at) yahoo com

[rodbargee]

Hi Costin

 

How did you get on with Gateshead Springs....

 

Adam