Why do lever drag reels produce more usable drag than star drag reels?

[Nasty Wendy]

This has probably been covered before so a redirect to that thread would be great.  Thanks guys for all you teach me.

[Swami805]

I'm by far no expert but I would think they have more friction surface to work with, the lever drag has the side of the spool, the star drag only what will fit in the main gear.Could be a few other factors too but I think that's the basic reason.

[akfish]

Actually, many star drag reels have more drag surface than lever drag reels because they have multiple drag washers (i.e., calculate the drag surface area of five 113H drag washers and compare that to the drag surface of a single TLD 20 drag washer). But my impression is that for comparable sized reels, star drags have more useable drag because they don't have a pinion bearing to crunch. No matter how you set your drag, you still have free spool on a star drag reel while too much drag will affect free spool in most lever drag reels -- and reduce useable drag.

[boon]

It's quite simple. Star drag stacks make far, far more drag than a lever drag - they have way more friction area (assuming it's a decent multi-stack) and the clamping force is much higher.
So why is the net drag on the spool so much less? Because the reel is a multiplier, and this applies in both directions - in exchange for you getting, say, a 5:1 retrieve ratio, the spool has a 5:1 mechanical advantage on the drag stack. In a lever drag it's obviously a 1:1 relationship as the drag acts directly on the spool.

If you are getting say 20lb of usable drag from a 5:1 star drag reel the drag stack itself is actually resisting 100lb of force.

[redsetta]

Doesn't sound quite right to me boon, but I'm definitely no engineer 

[Swami805]

yup i'm no expert so there you go

[Rothmar2]

Anyone for some Serious Mechanical engineering?

http://alantani.com/index.php?topic=14241.msg145318#msg145318

The best thread I have seen on this topic, with contributions from people I have great respect for.

[Tiddlerbasher]

Yep - well worth a re-read

[boon]

Doesn't sound quite right to me boon, but I'm definitely no engineer 

Respectfully, it is simple physics. A 5:1 gear setup provides a 5:1 increase in speed when the large gear is driven (i.e. by the handle) and a 5:1 increase in torque when the small gear is driven (i.e. by the spool). Think boat winch on a trailer for example.
The actual net force being resisted is not this perfect ratio because of the difference between the radius of the spool and the radius of the drive gear; in fact it is probably larger than the simple multiplication of the gears because the gear is likely smaller than the spool so the drag stack has less effective leverage. From the thread linked earlier (which also has some over simplification but gets close to the crux of the matter). One example presented 29lb of drag as 8.6Nm of torque being resisted by the drag stack; if the drag was acting directly on the spool (1.25 inch radius to point-of-pull) it would produce approx. 59lb of drag - which makes perfect sense as the reel in this example had, you guessed it, 2:1 gearing.

[rippin_lips]

I think it's more important to define what "more useable drag" is.  A wider range? Using the reel at a higher drag? A lever or star drag setup lends itself to different uses.  I would argue a star drag is more useful at or near its max drag than a lever drag.  A star drag does not have the same smooth range with easy adjustment that a lever drag has.

[jurelometer]

1.    What gives you the amount  drag in the drag design itself  is the coefficient of friction of the materials(the relative "stickiness"),  the amount of  clamping force on the drag surfaces,  and the  distance traveled per revolution.      You can fit a much larger disk on the side of a spool  (lever drag), than inside of the main gear (star drag).   So more braking work done per revolution per drag surface.  The same materials can be used on either design.

2.  Star drags generally stack multiple  drag disks-  so you get the multiplier effect.   This is less common in   lever drags.

3.   Gears provide leverage.  If your braking system is on the wrong side of  a 5:1 gear ratio,  it will need five times as much braking force to end up back where you started.     So a star drag with 5 drag surfaces gets you back to where you started from, IF the disks were as large,  which is usually not the case.  The diameter of the main gear only makes a difference in how large a diameter drag disk it will accomodate.  The gear ratio is the thing.

4.    A properly designed lever drag can have the dogs operate off the drag disk.   A star drag requires the dog (or ARB) to operate off the main gear (handle) shaft.    A 5:1 ratio means five times as much force on the dogs, if the ratchet/ pawl is the same diameter for both.  It is much easier to design in a large ratchet/pawl on a lever drag.  The larger the ratchet/pawl,  the less force on the dogs.

5.  The act of engaging a lever drag is typically gradual.   A star drag goes instantly from freespool to fully engaged, much tougher on the reel, esp.  at high drag settings.

6.   A single large disk ( lever drag) will generally do a better job of dissipating heat than a stacked set of smaller disks surrounded by a metal gear.  However, most lever drag reels  fully enclose the drag assembly in order to protect from contamination, decreasing this advantage. 

7.  The spool assembly is already pretty well aligned,  so it is easier to create a braking assembly that is consistent with less spots where the clamping force changes,  ergo a smoother drag.  Much more difficult to do this with  star drags.

In summary,  it is easier with a lever drag to design a reel that  will provide more drag,  engage more efficiently, and operate more smoothly.   However you have to look at a given reel to determine if the design advantages were actually utilized.  A well designed star drag could outperform a poorly designed lever drag.

[Gfish]

Best drag performance(to date) for me has been the Accurate twin drag system(lever drag). 2 drag discs on either side of the spool. Spendy, though.
This original question was a great one.

[redsetta]

Thanks boon - appreciate the explanation. Physics is clearly not my strong suit 

[basto]

Best drag performance(to date) for me has been the Accurate twin drag system(lever drag). 2 drag discs on either side of the spool. Spendy, though.

Yes, Best drag performance for me has been my twin drag Jigging Master PE5N. Also not cheap.

[jurelometer]

It's quite simple. Star drag stacks make far, far more drag than a lever drag - they have way more friction area (assuming it's a decent multi-stack) and the clamping force is much higher.
So why is the net drag on the spool so much less? Because the reel is a multiplier, and this applies in both directions - in exchange for you getting, say, a 5:1 retrieve ratio, the spool has a 5:1 mechanical advantage on the drag stack. In a lever drag it's obviously a 1:1 relationship as the drag acts directly on the spool.

If you are getting say 20lb of usable drag from a 5:1 star drag reel the drag stack itself is actually resisting 100lb of force.

Agree with Boon except for one nit:


At the risk of oversimplification :    Friction is weird.    The amount of force required  for two objects to slip  is a function of the clamping force and the coefficient of friction.  The size of the frictional area is irrelevant.

Since we are dealing with rotation,  the  diameter  does make a difference -  more distance traveled per revolution, means more braking work per revolution.  And the LARGER the inside diameter,  the better  (even though the area is decreased)-  a smaller inside diameter means more  of the load is traveling a a shorter  distance per revolution. There is a OD/ID formula for this,  I think that I have posted it  somewhere on this site.   

A common example is  the  disk brakes on a car.   The pads  clamp a relatively small area at the outer edge of the disk.   When the design requires more braking,  they go to a larger diameter disk,  not a pad with a greater area.

For fishing reels,  my guess is that it is easier/cheaper to get consistent clamping force with a full disk design than a narrow ring or caliper/pad.   There have been fly reel designs that have tried large/narrow friction rings  or calipers, and they generally  haven't fared as well as a full disk.  The main complaint was stickiness. 

Some lever drags have a fairly large ID on the drag pad,  but this is not universal.  I think when looking at two reels, the typical consumer will assume the one with a larger drag area is better.

-J