Happy Feet

That's the understatement of the year

Imagine surviving all these years without thru axles - or regular washing and aircraft quality maintenance.

Kapusta

OK, so after having clarified the difference between correlation and causation, I should now explain what correlation is and what it is not: To say that disc and TA in forks are correlated does NOT mean that every fork that is disc is TA or vice versa, unless it is stated that it is a perfect correlation (r = 1.0). Clearly there is a correlation between forks being disc and TA, but the correlation is not r =1.0. Or put more simply: the fact that there are QR/disc forks out there does not mean there is a lack of correlation between disc and TA.

The exact same question could be asked about disc brakes. Why did it take over 15 years after near complete adoption and proof of efficacy in mtb for discs to finally show up on road bikes in any significant numbers? I am guessing the answer is probably the same for disc and TA: Few understood the what the benefit was for road bikes. Again, correlation is not causation.

...and the explosion of road bikes with geometry aimed towards making them handle with stability rough roads (dirt and gravel)....
...and the move to running wider tires...
...and lower gearing options for road bikes...
...and now suspension popping up in some models..
...and Di2...

The first three (in addition to disc brakes) have been there for the taking for a very long time. I am unclear why among all of these things (including disc) that TA alone should need some OTHER technology to explain its timing.

This may or may not be the case. How do you know this is the reason they all want TA? (I prefer TA, but it has nothing to do with disc brakes, which I also like). Have you asked any of the manufacturers if this is why they are putting TA in disc forks? In any case, I addressed this in my last post.

I will not rule out that there COULD be causation here.

One scenario could be, as both you and I have suggested, that people wanting TA because of the discs caused the adoption of TA. You seem quite certain of this, I will not rule this out, but have my doubts.

Another possible scenario is that while TA is nice to have in any fork, it was not worth introducing a new fork and hub standard over for road bikes. However, once forks and hubs were being redesigned with new standards, adding TA was very easy. I guess that would not really be discs causing TA adoption, but more discs allowing it. But again, who knows?

livedarklions

Except for Di2, none of those are really new trends. All of those were hybrid features and yet those were almost universally QR until disks were adopted there.

You're putting words in my mouth--I never said it was the only reason people like TA. However, without disks, TA is a niche product for road bikes, requiring very expensive custom frames. Disks made them redesign the road frames anyway and some large number of people are going to want the TA because of the disks, so it's easier to take the TA road bike "mainstream" now. In other words, disks made the emergence of TA in large numbers road bikes possible.

Shall we argue the chicken-egg question now? Probably about as meaningful.

Kapusta

In light of the fact that most or our disagreements revolve largely around semantics, I suggest we move on to another debate.

I will let you choose the topic.

livedarklions

What is the proper lube to use while waving at a cyclist about to buy a bike from Walmart?

OBoile

This. While QR is not exactly difficult, I much prefer changing a wheel on my bike with a TA than my bikes with QR. It may be slightly slower, but it's virtually impossible to mess up in any way.

dabac

79pmooney

Yup. That someone might die from inattention to a detail that was never required on his previous bikes is just an inconsequential detail of far less importance than either aero or style points.

Ben

jlaw

But - regular washing does definitely make my bike lighter and makes me go waaay faaaaaster! (and I actually do like riding a clean bike)

jlaw

I agree - sometimes it's the little things that make a technology worthwhile.

On the other end of the spectrum are the drop-outs on my 2 'vintage' bikes that lack the retainer nubs - just loosen the QR and the wheel falls right out - Love It! Seriously.

Kapusta

Where is the evidence of all of these accidents? I mean, accidents happen from people forgetting to secure the QR, and the wheel falling off (with disc or rim), but where is there any evidence of there being more wheel-ejecting incidents with disc/qr wheels vs rim/qr wheels?

And regarding the forward-facing dropouts: many new qr/disc forks still have vertical dropouts. Rock Shox has 4 fork models available in disc/qr, and in all cases, the dropout is vertical. Same with Manitous 1 remaining QR Disc fork. And all six of RST's six XC fork lines. It does look like Suntour uses forward facing dropouts.

If this is really an issue that they are worried about being sued over, I am having a very hard time believing that after 20 years Rock Shox, Manitou, and RST would STILL continue to make the forks in such a way that would eject the wheels, simply to try and hold up some ruse (especially after Suntour has blown everyone's cover). They would have just quietly re-oriented the dropouts.

Think about it: did adding lawyer tabs open up fork manufacturers to litigation from when they did not include them?

My apologies for the lack of clarity of my post... it was meant to be a rhetorical question, intended to imply that disc was NOT the reason (or at least a significant reason) for TA.

dabac

Kapusta

My apologies for the lack of clarity of this post... it was meant to be a rhetorical question, intended to imply that disc was NOT the reason (or at least a significant reason) for TA.

In the spirit of Bike Forums, I am still happy to argue about it, but at least we can start such debates on the same page.

livedarklions

In anglo-american tort law, remedial measures are not admissible as evidence against the defendant for the rather obvious reason that to allow it would deter the defendant from doing anything to remove the hazard lest it be considered an admission of negligence. So lawyer tabs probably couldn't have been used as evidence against the defendant for incidents involving bikes before the tabs were introduced. If you produced bikes without them after they were introduced, the existence of such technology might be used against the defendant, however.

I doubt there's any publicly available database that compiles wheel ejectments sorted by cause. It's not like every bike accident has an investigation of some sort.

Am I wrong in thinking that the comparative ease of aligning the disk brakes with TA vs. QR is a rather big and marketable advantage?

Spoonrobot 

I don't think there's any quantitative data available for QR/Rim v. QR/Disc wheel falling out/ejection but there a web search shows dozens & dozens of self-reports and quite a few hits for lawsuits due to disc brakes. The QR/Rim lawsuits are all much much older and I would suspect could only be found with knowledge of the plaintiffs/defendants & case number or screening old usenet postings. Jobst Brandt makes mention of John Howard's testimony in a usenet posting from 2000 about QR loosening over time but no specific lawsuit is mentioned.

The dropouts for suspension forks with QR are inset inside of a lip and also have a specific service interval: https://www.ridefox.com/fox_tech_cen...nspection.html

Has this been posted? The images at the end are very illustrative of the issue and how it can be resolved with dropout orientation: https://cyclingtips.com/2015/10/road...axels-but-why/

I've had my downward facing dropout Soma fork loosen up over time. I think the issue was a aluminum acorn nut and external cam skewer. I replaced both with steel and internal cam and had no further issues. My other forks have forward facing dropouts and I have not had any issues neither with loosening or movement. I added witness marks to the dropout and over a few thousand miles of road/gravel the hub has not moved and the acorn nut has not loosened.

dabac

Should you wish to participate in such a discussion again, compare the TA assembly to a common (threadless) headset design.
Crown race is pressed on, usually with some force. That's positive centering/positioning there.
Top race often have a ring with a wedge-shaped cross-section that gets pushed down between top race and steerer tube by the wraparound piece of the stem when you tighten the top cap. Positive centering/positioning again.

And then there's the front hub.
Threaded onto a loosely fitting axle and clamped between two parallel surfaces by an undefined force. No contest really.
Not saying it HAS to perform poorly. But it's hardly surprising when it does. Its more dependent on production and installation tolerances.

Cyclist0108

This:





vs this:




My first generation Enve CX fork looks like the fork in the second image. I never have had an ejection event, but when I had external cam Salsa boutique QR skewers, I had to re-seat the wheel after every ride, or I would have disc brake rub, indicating a small amount of movement. Upon replacing these with Dura Ace (admittedly overkill) internal cam skewers, the problem went away.

The newer version of the Enve CX fork is through-axle.

fietsbob

As those Car Talk Guys on NPR suggested , the reason is the engineers
have to keep their boats seaworthy , and that's expensive,

so they have to keep making something new..

those "lawyer lips fork tips" keep your wheel

with the QR skewer properly tightened from coming out in normal use.



I have an inconvenience, non QR, security skewer in my 1 disc brake bike ..

I just use an L hex wrench to loosen or tighten it..






...

fietsbob

German Bike company Tout Terrain has made forks with forward opening fork tips as described in
above graphic, of torque center changes .
Other builders solved it by putting the caliper on the right fork blade,
so torque center shift forced the hub axle more into the dropout..

fietsbob

Dinosaurs laid eggs , chickens descended from those dinosaurs a few million years later.

so paleontology solved that one...

livedarklions

Solved it for the generic "egg" you mean. For the specific "chicken egg", presumably there was a point where a not quite chicken laid an egg that hatched a chicken.

To make this relevant to the forum, what are the best bike gloves to wear while eating fried chicken?

fietsbob

Neoprene , for keeping the grease, chicken fat, off your hands..

fietsbob

Indeed, .. for the very worry prone..

Koyote

Last year I bought my first disc brake-equipped bike, and the first things I replaced were the cheap open cam QRs with Shimano XT skewers. Cost $27 and gives me peace of mind.

csrpenfab

I'm two weeks into ownership of my next Trek FX6 Sport with hydraulic discs and thru axles. I have yet to see a drawback. The wheels are totally secure, with zero chance of coming out. Placing a wheel takes all of 10 seconds with very little fiddling required.