Both the start nut and compression plug are for bike forks but these are not installed on the same material as bike forks, aluminum, and steel steering tubes have star nuts installed in their forks and the compression plugs are modern plugs and are recommended for carbon fiber forks. but there are also a few categories of bikes that are still using star nut plugs in their carbo bikes for example Cannondale bikes. star nuts are specific for metal frame bikes because these would rub and scratch carbon forks, it is the reason these are not used for carbon forks. Star nuts are lighter in weight as compared to compression plugs and also there are old with poor looks than that of compression plugs, star nuts are more durable and strong than that compression plugs.
The top cap of the stem body is also specific for these plugs, and if you insert star nuts in carbon forks the top cap does not make a compatible relationship with the star nuts due to which forks will start unscrewing and dismounting, as a result, fork loses. the old model and traditional star nuts are M6 bolts and if you will check the compatibility, then these M6 bolts are compatible with the new carbon fork compression plugs, so if your fork is of carbon material then you can easily select M6 bolts instead of star nuts in place of compression plugs.
The stem cap body also has different thread sizing and it is difficult to select the specific compatible plug for the carbon and aluminum forks. but you can check the compression plug for mounting on the aluminum frame, if it fitting accurately then it does not mean that it is a safer way to run your bike in this setup because there is a large difference between the aluminum and carbon forks, their width and diameters are different from each other, it is the reason that star nuts and compression are specific for them.
the headset of the handlebar has bearings, which need their specific plugs, if you are adjusting the star nut on a carbon fork and the compression plug on an aluminum or steel fork, then the bearings of the headset would press and cause friction, tools are different for star nut and compression plugs, so if you want to insert compression plug in an aluminum steered then you have to replace or change the stem bolt of the headset if the stem bolt is compatible with the compression plug then you can easily insert compression plug but this setup is for temporary use, you have to change the compression plug with a star nut for an aluminum steerer tube.
What Are The Main Risks Of Inserting Compression Plug-In An Aluminum Steerer Fork?
Compression plugs are specific for carbon steerer forks so if you insert them in the opposite way, then they will not tighten themselves with the3 aluminum fork and it remains loose, when you ride on rough and hard trails you will notice the plug start wobbling and vibrating, and losing itself, it is a risky step, if you are a mountain biker and trails are hard and aggressive then compression plugs are strictly not allowed for aluminum forks, the headset of the stem body starts shaking and you will loose gripping and handling of your bike on the trails.
Difference Between Compression Plug And Star Nut:
The compression plug is solid in nature and does not move with the carbon steerer forks, the stiffness is relative to the carbon fiber stiffness, but star nuts are not stiffer, these contain small spring-like materials and these will vibrate upward and downward within the aluminum frame, so if you interchange them each other these will work differently.
Compression plugs are simply installed by pushing your palm on the top surface but star nuts require tools that are expensive, so if you insert a star nut within a carbon steerer fork and start pushing with your palm hand or with the hammer, you will break or split your carbon fork, because star nut insertion is also harder than compression plugs.
Compression plugs require less striking force than star nuts because star nuts require proper tools and you have to hit with tools on the top surface of the nuts which will sometimes break or crack the edges and surface of the star nuts, so these are the preventive measures which you need to remember before inserting plugs within the headset of the forks.
Star nuts have a greater width and these are wider in diameter as compared to compression plugs so there are many brands of compression plugs that are used for both carbon and aluminum steerer tubes, because these plugs are wider than the normal plugs, if you will find a wider compatible plug for both carbon and aluminum forks, then you can use it for both types of forks in the future.
Thickness Of Steerer Walls For Compression Plugs:
Carbon fiber forks have the same specifications and the width and diameter of the sidewall of the carbon forks are universal for all forks carbon forks have narrow diameter of sidewalls, but if we discuss the steel and aluminum then, the diameter and width of their walls are different and vary from fork to fork and also aluminum and steel sidewalls have a greater thickness than carbon sidewalls, that’s the reason compression plugs are not installed and inserted within the steel and aluminum forks.
There is a larger noticeable difference between star nuts and compression plugs, and also tools of star nuts are more expensive than compression plugs, so if you want to replace a compression plug with a star nut, then you have to find your own hand-made tool for the insertion of the star nut, these are inserted in the straight vertical position, if you have inserted in a wrong angle then it will not tolerate bumps ad jumps of teh trails and your headset will start losing and vibrating.