Are linear tracking arms better than pivoted arms?

Let us not forget that pivot arm also has friction (owing to slow tracking speed, this is static and not dynamic coefficient of friction) at the bearing and due to this friction the arm would also have "+/- X force" (x force normal to the pivot arm longitudinal axis). This is in addition to the y component working along axis of the arm. Any ME or SE can draw a simple free body diagram to balance primary force vectors.

Your intuition would tell you that this force would be lower than that in the linear arms, but it depends. It depends on the effective static mass at the friction interface- longer and heavier the arm, greater the friction force. Thus longer and heavier arms with mechanical pivot/bearing may have higher friction force than say shorter wand on linear arm with mechanical 'sliding friction' bearing.( an air bearing would even be further lower)

Of course, we are talking about a small force values here- tenth of grams. milli grams or even micro grams of friction force depending upon the arm mass etc.

It would be good to know how and what design load s cartridges (the stylus, suspension and suspension to cartridge body interface) and are designed at. Static and dynamic loads. Naturally owing to the function of cartridge, the stylus and the rest of the 'structure' would be designed with cantilever beam loading idealization and thus would have certain design capability (static and cyclic based fatigue) in both x and y directions (and of course the z direction) to be be able to withstand x and y load induced during tracking wavy grooves.

So without looking at hard numbers on free body with two samples of linear and pivot arms it is hard to say which one has more x (excessive damaging forces). I tend to think air bearing linear arm would be approaching (Or even lower than) light weight pivot arm.

Rather than generalization, I would like to see free body force values for a set up compared with cartridge design values (both static and fatigue(-number of cycles- I bet you cart manufacturers should have this)

Until then the real life experiences are good indication to base the 'judgement' on. And we do have experiences from both camp.

Nilthepill, interesting points. In the horizontal a linear air bearing design has the advantage of zero static or dynamic friction. Moreover, assuming good eccentricity of LP, within certain limits the higher lateral mass of a linear arm could actually be an advantage, insofar as an inertial mass with constant momentum toward spindle would tend to reduce centripital force required to advance stylus.

I love this, Nilthepill! In class, we have been studying free body diagrams...now, if only I could introduce this as a real-life application to the mp3 generation :-)

Vbr,
Sam

Dgarretson you are right - a very short linear tonearm (like Souther or Versa Dynamics) can indeed feature very little horizontal effective mass.
But much more important it features a very small (= short) lever.
As said earlier - the very short linear tonearms do not show the big problem with the long lever and subsequently the huge lateral force applied by this lever to promote progression.
THese short linear trackers (and this was recognized by their designers) do have problems with not only warped records, but with every little tiny height difference in record surface (and there usually are hundreds of tiny valleys and hills for your stylus while tracking a record groove).
The problem here is, that the vertical lever is very short too and thus every little tiny height difference on the record is huge for the cantilever and stylus. Huge VTA/SRA changes in a long row - up and down the groove highway over the many lovely hills and valleys of the lake district in the midlands of Britain.....

Seriously - as Mentioned before - the problems of the linear trackers are all mechanical issues of the most basic mechanical laws and models.
It is not about friction - it is about long and short levers and the point that the stylus commands the progression.
These problems can all be solved. No doubt about that. "We, the people..." long have all needed electronic and mechanical tools at hand to design and produce a linear tracking tonearm allowing any cartridge to track at zero error line without applying any lateral force on the cantilever at any time.
A linear tracker with groove margin compliant progression independent from any derivation of the cartridge/stylus/armwand.
It is not a big deal, but it has not been done yet.
That was all I am saying so far.
I certainly do not want to tease any owner of linear tonearms. I too did own most major linear tonearms too.
Each of them had its promises and was tempting in one or two sonic details. But none so far did address all the issues in linear tonearm design.
It is not about any heroic design attempt either - there are no heroes in audio, thus we won't see any heroic design.
After all, a hero is someone overcoming his/her fear, fighting the battle, eventually surviving and maybe finds someone who remembers and tells the story.
The physical model of linear tracking tonearm with its force vectors is there. It is no secret.
But just because there are some linear trackers out there since the early 1960ies, doesn't mean that the concept has already been brought to its promises.