Why do they use torx screws on disc brakes.

[SouthYarraSage]

It's so muppets don't undo anything they shouldn't.

Pretty crap idea. Make something idiotproof and someone just invents a better idiot.

 

[akashra]

Torx head screws allow bolts to be constructed out of lighter and softer materials, while being able to tolerate a much higher amount of torque without risking cam out - Phillips heads are designed to causecam out, Torx are designed to prevent it. Disc brakes are usually torqued much higher than a comparative bolt on another part, using a much tighter thread, so a stripped bolt head can be much harder to remove from the hub without having to destroy the bolt, and potentially the hub.

I sometimes wonder, however, why disk brakes use Torx and not Security Torx.

 

[D_Nine]

Don't understand where this "high torque" comment keeps coming from ? Recommended torque for rotor bolts is ussually 6.2nm, this is not much more than hand tight ! As to why they choose torx bolts ? No idea but will investigate.Any engineers out there that know of benefits or reasons ? (Keyboard experts need not apply !!)

 

[fairy1]

Recommended torque for rotor bolts is ussually 6.2nm, this is not much more than hand tight !

So I need to use a rattlegun? That was where I was going wrong, thanks.

 

[Registered Nutcase]

Don't understand where this "high torque" comment keeps coming from ? Recommended torque for rotor bolts is ussually 6.2nm, this is not much more than hand tight ! As to why they choose torx bolts ? No idea but will investigate.Any engineers out there that know of benefits or reasons ? (Keyboard experts need not apply !!)

Its not the torque that is being put on the bolt, it can take higher torque where you put your tool before it rounds... it has a huge amount of surface area.

 

[muskimo]

as stated just above not only are they able to take high amounts of torque, its a combination of this and more contact area thus allowing the bolt to be done up, un done, done up, un done, done up etc etc etc, with out (usually) any damage caused to the bolt or tool.

 

[GTBoy]

They don't seem to cam out as easily as hex i must admit, but if they do it really does seem to damage them. I cammed out (not sure that even a term but I'm going with it) on one, and it really rounded the edges of it, after that I made sure it didn't happen on the others.

 

[beno]

too all those complaining of skinned knuckles here's a little trick! Use and old hollow QR axle to extend the torx tool and you ahve no more probs! I also use a drill with a T25 bit to undo and do up rotor bolts, just make sure you tighten them by hand! Very important.

 

[Old Shagger]

info

The Torx (T25) is used because;
The height of the head is relative to the depth of the 'drive'.
Rotor bolts need to normally have a shallow,thin, small head height. If you look at a allen key hex drive in a normal SHCS (socket head capscrew), the depth of the drive is much deeper than a torx drive in the comparable screw size.

It has nothing to do with tightning strength as the nm recommended is very small as noted by others.

If a large deep hex allen key drive was put in the shallow head needed, the head would 'pop'off as soon as it was tensioned, as there would be no material in the head of the screw.
The closest you can get which is 'inbetween' the 2 is a button head capscrew. Yes its a hex drive and head height is inbetween. I use these in Stainless steel and have had no issues, and an allen key is SO much easier to use.

 

[scuba05]

I thought it was a mixture of things, but mainly for security. Most things you will notice straight away when you sit on your bike if they are missing, but a rotor? probably wont notice until its too late. Not as many people have torx keys as compared to allen keys, so it would be less likely to get removed.

That, and as previous people have stated, more torque can be exerted onto a torx key over an allen key.

 

[fairy1]

Seriously, three pages on why the use Torx bolts for brake rotors.
Someone should make it a sticky so this never happens again.

 

[muskimo]

I thought it was a mixture of things, but mainly for security. Most things you will notice straight away when you sit on your bike if they are missing, but a rotor? probably wont notice until its too late. Not as many people have torx keys as compared to allen keys, so it would be less likely to get removed.

That, and as previous people have stated, more torque can be exerted onto a torx key over an allen key.

have a second thought about this, first you would have to take the front or rear wheel off, most need tools for this, some special tools, and if you did get the wheel off, would you take the rotor off and leave the wheel?? ?
if someone was to go through so much effort, it would be easier to bring bolt cutters and scoot on the whole thing.

 

[bear the bear]

as stated just above not only are they able to take high amounts of torque, its a combination of this and more contact area thus allowing the bolt to be done up, un done, done up, un done, done up etc etc etc, with out (usually) any damage caused to the bolt or tool.

Expect your f&*ken knuckles.....


torx head bolts are the devils tool

 

[muskimo]

i never have any dramas with any of my torx or allen tools. quality tools and quality bolts mesh perfectly and dont slip.

 

[Yellm]

Torx are here to stay...

I think we just have to take it, Torx is here to stay. Have a look at the components around. A large amount of the current SRAM gear uses Torx heads now, at least when I look at my XX group set, that's all I can find. No more screw driver for the derailleur adjustments... just torx.

When I look at my Formula brakes, they only use Torx heads. Why? Because apparently this is the only way they were able to completely optimise every single bolt for its application. For every bolt or screw they have chosen just the size required for desired function, and have thus been able to make the lightest brakes on the market. Many of the small screws are aluminium. I think as an allenkey head the bolt would have had to have been bigger and rounding is more likely. Formula has one very small multi tool with all the neccesary torx, I think that is a sweet solution. Just get a complete set of allen and torx tools and enjoy being able to do everything on your bike. It may be an investment, but working on my bike has been such fun since I got my self all the necesary tooling. I can only recomend it!

I believe most Cranks (even shimano) use Torx chainring bolts now as well...

Aren't torx screw (compare Ti screws) a tad lighter too? Sure it's only a bit, but in the end it all ads up.