Stahlbus brake bleed valve - right front for 22 RS

[JtL]

Does anyone know the correct PN (or even thread details) of the right front caliper bleed valve?  2022 RS.

Left is fine, but not the right.

Stahlbus themselves don't seem to know as they haven't had a bike top play with apparently, although one of their parts will fit.  Seems a bit odd, but there you go...

[Liteitup]

Might check here

http://www.speedbleeder.com/bikechart.htm

SB6100

[JtL]

Thanks - I may have to use Speedbleeders although my preference is the Stahlbus.

[Liteitup]

Further research leads me to believe the speedbleeder part # refers to thread size and pitch.

Sb6100 is M6x1 per the chart at bottom of this chart
https://www.revzilla.com/assets/0003/203...lpha_2.pdf

[Grumpy Goat]

Thanks - I may have to use Speedbleeders although my preference is the Stahlbus.

Any specific reason?

[JtL]

The Stahlbus strike me a better made, and they only screw into the caliper once and done, as they are in two parts, versus the Speedbleeders in & out each time. Not that there should be much in & out anyway, once every couple of years.

Thanks, Liteitup - I had missed that table - might be exactly what I'm looking for.

[Liteitup]

Apologies, I was looking at the wrong column. SB6100 is for the left.


SB8125L looks like the size for right front. M8x1.25



Heck, don't trust me, I've misread the chart three times in a row.

[JtL]

I've just had what - to me - was a very strange conversation with Speedbleeders. Apparently, there's no strength difference between the standard and stainless units, which I find unlikely.

Secondly, and from an engineering perspective this is plain wrong, the person I spoke with recommended a 6-side wrench, and specifically not a socket, further, a specific make-up torque wasn't suggested.

This latter I find ridiculous as the implication was that too much torque would be applied and the bleeder would be snapped off.  I quote "you can't feel with a socket".

To the very best of my knowledge, every thread is designed for a specific torque and I even have a couple of tools which go down to tools which go down to 3 NM.  Bicycle people probably have many of the same tools.

Overall the conversation wasn't confidence inspiring.

[Grumpy Goat]

I've just had what - to me - was a very strange conversation with Speedbleeders. Apparently, there's no strength difference between the standard and stainless units, which I find unlikely.

Secondly, and from an engineering perspective this is plain wrong, the person I spoke with recommended a 6-side wrench, and specifically not a socket, further, a specific make-up torque wasn't suggested.

This latter I find ridiculous as the implication was that too much torque would be applied and the bleeder would be snapped off.  I quote "you can't feel with a socket".

To the very best of my knowledge, every thread is designed for a specific torque and I even have a couple of tools which go down to tools which go down to 3 NM.  Bicycle people probably have many of the same tools.

Overall the conversation wasn't confidence inspiring.

We could have many discussions on fastener torque but at the end of the day the torque applied to a fastener is not dependent on the thread geometry, but on the desired clamping force. If the shank on which the threads are laid is weak then the torque specified could be limited by the shear capacity fo that shank as opposed to any clamping force that may be contemplated. That is shy Speedbleeders are suggesting that there is no [discernible to the wrist] strength difference between the standard and the stainless units.

I agree that the lack of specification of torque is bordering on the ridiculous, but when it comes to the low value of same (due to weakness of the shank of the tiny bleeder) then it makes sense. I do have some personal experience in this area.

[JtL]

Broadly, I agree with you, and I should have been more specific, using the term threaded body rather than simply thread.  I also agree with you that the desired end result is clamping force, and usually it is the end clamping force which has strong influence over the chosen thread, although obviously there are many other factors at work too.

I have to disagree with you here, but it may simply be semantics: my contention is that the same item made of different materials should have a strength differential, one to the other, which may or may not require different torque values.  You only have to consider bolt grades available from say McMaster.  Likely, in the case of Speedbleeders the desired make up torque is the same regardless of material composition.

For theses tiny items, I'm painfully aware of how easy they are to damage, and especially when it's a hard but thin and apparently easily broken steel object being screwed into a softer (& much more expensive) piece of alloy. In these cases, a known and observed make-up torque is even more critical, I would have thought, but that's just my opinion.

"I do have some personal experience in this area" presumably referring to the SB that just broke, which might perhaps have been avoidable with known torque values or better manufacturing?  Presumably one or the other as there aren't many other options.

[MrVvrroomm]

Stainless is not stronger than carbon steel. Speed Bleeders, once installed, are never removed. You only need to open bleed valve 1/2 turn, as in any manual brake bleed valve.

Speed Bleeders are same for all models of liquid cooled boxers. Yes, I know they are three different brake calipers with three different sizes.

Using a torque wrench on ANY fastener that is not clean, dry, new is a recipe for disaster.

[JtL]

Stainless is not stronger than carbon steel.  Speed Bleeders, once installed, are never removed.  You only need to open bleed valve 1/2 turn, as in any manual brake bleed valve.

Speed Bleeders are same for all models of liquid cooled boxers.  Yes, I know they are three different brake calipers with three different sizes.

Using a torque wrench on ANY fastener that is not clean, dry, new is a recipe for disaster.

I asked if there was a strength differential, not expecting stainless to be stronger than carbon, although 'stronger' is a very vague, non-descriptive term.  Certain grades of stainless are more 

As for 'Using a torque wrench on ANY fastener that is not clean, dry, new is a recipe for disaster' - great, my point exactly! Speedbleeder recommended a 6 sided wrench, specifically not a socket "as you can't feel anything" (amazing!), and couldn't provide a torque value, and specifically did not recommend a torque wrench.  Obviously without said value, using a torque wrench is totally pointless.

[Grumpy Goat]

Stainless is not stronger than carbon steel.  Speed Bleeders, once installed, are never removed.  You only need to open bleed valve 1/2 turn, as in any manual brake bleed valve.

I knew I forgot to mention something in my reply ... 

[MrVvrroomm]

You can't use a socket on the smaller Speed Bleeders because it won't slip over the end and still purchase flats of bleeder valve.

Most wannabe mechanics over-use torque wrenches. If it doesn't vibrate and/or get hot there is no need to use a torque wrench.

[Grumpy Goat]

I have to disagree with you here, but it may simply be semantics: my contention is that the same item made of different materials should have a strength differential, one to the other, which may or may not require different torque values.  You only have to consider bolt grades available from say McMaster. 

Agree or disagee it doesn't matter. If you read again what I said you'd see I put in the bit in square brackets to qualify what I said, i.e. "[discernible to the wrist]". While there may be differences in material strength, to the wrist at that size of bleeder there is no difference; they will all twist off easily. Any difference are relegated to forum discussions ... 

[Grumpy Goat]

You can't use a socket on the smaller Speed Bleeders because it won't slip over the end and still purchase flats of bleeder valve.

Most wannabe mechanics over-use torque wrenches.  If it doesn't vibrate and/or get hot there is no need to use a torque wrench.

Agree on both counts.

[JtL]

As long as what you do works for you, that's great.

Had to laugh about wannabe mechanics and torque-wrenches.  I'd have said exactly the opposite, when it comes to being absolutely precise, as would most Formula One pit crews.

On the Stahlbus items you can easily get a socket - which I prefer to a wrench - onto both parts, body & nipple.  I'd definitely use a torque-wrench to install the body into the caliper but wouldn't bother for the nipples.

Personally, I enjoy precision, unlike the people at the local tire shop who routinely wildly over-tighten wheel bolts

I think more of an issue is that too many people are too cheap to buy a decent set of torque wrenches, and/or understand how and when to use them. No surprise, many understand how to use a helicoil.

Not that long ago, an STL file was sent up to the ISS so the astronauts could 3D print a special wrench to tighten a bolt to 2NM - the wrench is available on Thingiverse for the curious.

Spent a little time with the Martini Offshore powerboat team.  EVERYTHING was tightened extremely carefully. I'd never seen such a wide range, and quantity, of ultra-high quality torque-wrenches.

My '74 Norton is different - I could hammer things into place and it would be fine.