Grab-a-track leaf springs

[reenmachine]

The person I spoke to told me that the standard spring came in a 205lbs spring rate. I thought that it was going to be too stiff for the street. That's when he told me that the glass and steel rates were different. A 205lbs glass would be much softer than a 205 steel spring. I could order any rate I wanted, but without being able to compare it to a steel spring rate I'd just kinda be guessing.

That makes absolutely no sense to me at all. A spring rate is a spring rate no matter if the spring is made of steel, fiberglass, titanium, rubber, air, or whatever. If the rate is 205 lb/in then there's 205 lbf exerted per inch of deflection, period.

Different materials will have different characteristics as far as the speed at which they can react, weight, etc., but to say a spring is "softer" than another with the same rate just doesn't make sense.

 

[Hack]

That makes absolutely no sense to me at all. A spring rate is a spring rate no matter if the spring is made of steel, fiberglass, titanium, rubber, air, or whatever. If the rate is 205 lb/in then there's 205 lbf exerted per inch of deflection, period.

Different materials will have different characteristics as far as the speed at which they can react, weight, etc., but to say a spring is "softer" than another with the same rate just doesn't make sense.

.. unless the sales guy was talking about stiction. But then why didn't he say stiction between the individual metal leafs is the difference? Sounds to me like a lack of training or something. Or possibly as the spring is deflected there is a change in the spring rate. The spring rates of fiberglass and metal leafs could be the same at installed height, but diverge under compression or extension.

 

[reenmachine]

.. unless the sales guy was talking about stiction. But then why didn't he say stiction between the individual metal leafs is the difference? Sounds to me like a lack of training or something. Or possibly as the spring is deflected there is a change in the spring rate. The spring rates of fiberglass and metal leafs could be the same at installed height, but diverge under compression or extension.

Well, if he was talking about stiction he should have said so, or said they were smoother or something. And if he was implying that they are progressive rate then that's a whole other thing altogether. Neither of those things should be expressed as "softer".

 

[mikethebike]

That makes absolutely no sense to me at all. A spring rate is a spring rate no matter if the spring is made of steel, fiberglass, titanium, rubber, air, or whatever. If the rate is 205 lb/in then there's 205 lbf exerted per inch of deflection, period.

Different materials will have different characteristics as far as the speed at which they can react, weight, etc., but to say a spring is "softer" than another with the same rate just doesn't make sense.

I don't think the people who answer the phone at any of these places knows a thing about the product. The guys at S&S Motorcycle didn't know how to calculate H.P.! The guys at Heidts didn't know what the Ackerman was.

I agree with your assesment of the differences in an IRS and a leaf spring solid alxe but that's why we have panhard bars and trailing arms. The only advantages of the mono-glass spring that I see are the weight savings and the elimination of stiction. Let's face it, if you can reduce unsprung weight by 30 or 40 lbs. (without having to do a complete and multi thousand dollar redesign) you have approached the Holy Grail of suspension improvement. If you remember GM tried a mono-leaf steel spring in the 68 Nova for that very purpose.

Think about this...if you wanted to install a Versailles disc brake axle and you used glass springs you should come out with about the same unsprung weight as a stock drum 8" with steel springs.

 

[Hack]

Well, if he was talking about stiction he should have said so, or said they were smoother or something. And if he was implying that they are progressive rate then that's a whole other thing altogether. Neither of those things should be expressed as "softer".

Agreed. Like Mike said - it's got to be a training or capability issue. Typically these people are picked for good verbal interactive skills and their technical ability is nil.

 

[Jimmys66]

Agreed. Like Mike said - it's got to be a training or capability issue. Typically these people are picked for good verbal interactive skills and their technical ability is nil.

I'm almost certain this was the case......When he gave me the "softer" speech, I started asking questions. Questions that couldn't get answered. The person I talked to on the phone didn't seem to have alot of automotive knowledge at all. When I asked if there was some one that could answer my questions, I was told no. I lost faith in buying the product for lack of the person on the phone to be able to properly explain the product.

I agree. To me, spring rate is spring rate, no matter what the composition of the spring is made of. 205lbs is 205lbs.

Maybe someone else will have better luck on the phone.