Nubster
Narrowed down to two bikes. One had 135 QR rear and the other is 142x12. How much actual difference is there, if any? Is it something that I will likely notice? Will I regret not getting the 142x12 6 months from now? Should it be a deciding factor when choosing between the two bikes?
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GOTA
Deciding factor?  No. 

It's not like you are using a suspension fork on your gravel bike.  I've had a Salsa Colossal with disc brakes and QR for years now and it never has been an issue.  I'm 225 so stiffness can be noticeable but not in this case.  That's strictly a road bike with 28 mm tires max so it's a little different.

From what I've read the bigger issue is frame design.  For a regular 135 QR rear the chainstays need to be longer for disc brake bikes.  Shimano recommends 120 but my Colossal had 115 without any issues.  The 142 would allow for shorter chainstays which is usually for racier bikes.  Is that really a factor on gravel bikes where stability is more important?  I wouldn't think so.

The bigger issue to me would be if they are using proprietary hubs like Specialized or Cervelo often do.  I've seen too much of that to make disc brakes worth with one system or another.  That would be a deciding factor to me.
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RoverAl
I am a recreational rider, solo adventurer, paved, dirt, sand or whatever. I put 2-3k miles a year on my bikes. My new bike Willard has TA'S front and back. IMO there is a noticeable difference with TA'S. Downhills are rock solid, straighter tracking. More confidence at speed.  Braking is better. The solid bolt on security. Many builders are leaning towards this feature. I've had QR'S come loose before. 
Installing the rear wheel is a little awkward but other than that I think they are great.

Yes  I think you would miss having them in a few months because you would be wondering what if? Yes you will notice a difference,yes Get them you won't regret it. Resale value having TA'S is a perk for some. As I upgrade I will only buy a bike with TA'S
Just one mans opinion! Can't measure the results.
What's not to like about them???
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GOTA
It's definitely a great feature.  What I'm talking about is whether thru axles are a deciding factor.  To me the deciding factors are fit and price.  Fit is the first.  If the bike doesn't fit then forget it.  

Like most I have a budget.  Does the bike offer good value for money?  Will I have to replace a lot of the components quickly?  I tend to upgrade wheelsets, tires and seats when I buy a new bike.  If I have to invest in replacing a flexy crank or poor brakes then what is a good deal could be very expensive.

I know for some features really matter.  If he bike has a press fit bottom bracket it's off the list.  If it doesn't have enough tire clearance or mounts for racks and fenders it's off the list.  That is how I see the QR vs TA debate.  If I could get TA or any of those other things they are a bonus but none of them trump fit or price.  It really comes down to how important these items are to you.
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Nubster
Parts aren't too much an issue with either bike. One has SRAM which I prefer but it has the 135 rear but does have a 15mm front axle which this time around is mandatory. Disc brake both bikes. The other is Shimano 105 with discs which I can deal with...solid group for sure, just not my preference. But it does have the 142 rear and 15mm front axle. Saddle is covered already. Other components not worried about too much. Fit I don't think will be a problem either. Price is 4600 difference with the 135 Sram bike being cheaper. Comparing geometries between bikes...there's some differences and there's some stuff very close to the same. I don't know enough about that stuff to determine what does what really when it comes to geo numbers.
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drwelby
GOTA wrote:

From what I've read the bigger issue is frame design.  For a regular 135 QR rear the chainstays need to be longer for disc brake bikes.  Shimano recommends 120 but my Colossal had 115 without any issues.  The 142 would allow for shorter chainstays which is usually for racier bikes.


No, this isn't the case. The frame and hub are in exactly the same place except the extra 3.5mm of axle that fits in the recess in the dropout. You might be thinking about Boost which pushes the chain line out which can help make for shorter chainstays.

The key benefit for through-axles on a rigid bike is better repeatability of wheel positioning. Once you set up your disc brake pads your disc will end up in the right place every time you put your wheel back in.
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downhillsfast
I have a Grade Carbon SRAM with TA on front and QR rear. I love the bike but for what it's worth I would definitely look for TA rear next time. Lots of fiddling with QR to get wheel into correct position with disc brake, and after a few longer and more aggressive rides I just happened to notice that the QR was loose. This could have been dangerous. So I would say it's not the only feature to decide on, and there is the issue of compatibility with more wheelsets/hubs but yes it does make a difference.
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Slim
It depends on the design, you could have a QR dropout fame that was stiffer than a through axle, so whether or not you would notice it on two different bikes we can not say.
I also managed to operate my mtb with a qr and disc brakes for awhile.
That being said, I've had stiffness issues, alignment issues and problems with skewers holding tight, so if I had the choice I would choose the T-A.

However, the are other considerations too. Do you like the geometry/tire clearance of one frame more than the other?

In short, if all else is a draw, I would certainly pick the T-A frame over the QR frame, but not if it meant giving up good geometry or tire clearance.
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GOTA
drwelby wrote:


No, this isn't the case. The frame and hub are in exactly the same place except the extra 3.5mm of axle that fits in the recess in the dropout. You might be thinking about Boost which pushes the chain line out which can help make for shorter chainstays.

The key benefit for through-axles on a rigid bike is better repeatability of wheel positioning. Once you set up your disc brake pads your disc will end up in the right place every time you put your wheel back in.


This is where I got that from.  These guys are pretty good wheel builders.  They are also very much pro TA

http://www.novemberbicycles.com/blog/2015/7/22/thru-axles-vs-quick-release.html

"The quick release standard for disc rears is to have the dropouts 135mm apart, with 10mm diameter dropouts. Already on road bikes, which often have chain stays about 405mm long, the 135mm spacing causes some friction. First, it's hard to keep your heels clear of hitting the wider-spread chainstays (especially when you're a duck-footed freak like me). Second, the chain line gets more tortured as you shift to the outer cogs. Shimano says you need a 420mm chainstay for their drive trains to work correctly on 135mm rears. Specialized goes so far as to move the drive side flanges inboard on many of their disc hubs so that you can use the full gear range even with a 405mm chainstay. The problems with that are that you're somewhat limited to their hubs with their bikes, and moving the inboard flange in is precisely what you don't want to do from the wheel's perspective. For what it's worth, you can totally use a normal hub in these Specialized bikes, you just don't want to do any small-to-small cross-chaining - even if you are Andy Schleck."
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drwelby
Yes, but what they're talking about is going from the existing 130 road spacing to 135 mountain spacing used on almost all disc hubs. 

135 QR and 142 TA are the same thing. The extra 3.5mm of axle on each side fits into the recess in the dropout. But where the flanges and cassette end up are the same and the inside of the dropout face is still 135mm.
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GOTA
drwelby wrote:
Yes, but what they're talking about is going from the existing 130 road spacing to 135 mountain spacing used on almost all disc hubs. 

135 QR and 142 TA are the same thing. The extra 3.5mm of axle on each side fits into the recess in the dropout. But the end caps are still 135mm wide.


I understand what you are saying.  Thanks


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WFRTony
Here is a link that helped me understand the difference:

http://blog.artscyclery.com/mountain/rubber-side-down-axle-standards/
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shiggy
Nubster wrote:
Narrowed down to two bikes. One had 135 QR rear and the other is 142x12. How much actual difference is there, if any? Is it something that I will likely notice? Will I regret not getting the 142x12 6 months from now? Should it be a deciding factor when choosing between the two bikes?

Metal frame: does not matter.
Carbon frame: go through axle. I have seen and experienced the wheel coming loose in an open dropout, including the wheel coming completely out of the frame in a crash.
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shiggy
GOTA wrote:


This is where I got that from.  These guys are pretty good wheel builders.  They are also very much pro TA

http://www.novemberbicycles.com/blog/2015/7/22/thru-axles-vs-quick-release.html

"The quick release standard for disc rears is to have the dropouts 135mm apart, with 10mm diameter dropouts. Already on road bikes, which often have chain stays about 405mm long, the 135mm spacing causes some friction. First, it's hard to keep your heels clear of hitting the wider-spread chainstays (especially when you're a duck-footed freak like me). Second, the chain line gets more tortured as you shift to the outer cogs. Shimano says you need a 420mm chainstay for their drive trains to work correctly on 135mm rears. Specialized goes so far as to move the drive side flanges inboard on many of their disc hubs so that you can use the full gear range even with a 405mm chainstay. The problems with that are that you're somewhat limited to their hubs with their bikes, and moving the inboard flange in is precisely what you don't want to do from the wheel's perspective. For what it's worth, you can totally use a normal hub in these Specialized bikes, you just don't want to do any small-to-small cross-chaining - even if you are Andy Schleck."


I disagree with the majority of their claims in that piece, from chainline to braking forces.

Agree with heal clearance, but that is only a problem with chainstay mounted calipers and poorly designed frames.
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Nubster
shiggy wrote:
Metal frame: does not matter. Carbon frame: go through axle. I have seen and experienced the wheel coming loose in an open dropout, including the wheel coming completely out of the frame in a crash.


Guess I should say that at this point 142x12 isn't really an option. I don't want a metal frame bike or at least there isn't one that I'm really liking that I can afford and the carbon bike options that I have at this point in time are 135 QR. The Renegade is off the table since the Expert is sold out and I can't afford the Elite. There's a 2015 Elite that was listed on Monday but Jamis has their head up their ass and won't return my dealer's phone calls so I don't know if that bike is even available or what the price is...but regardless...it's a 135 QR rear. So pretty much...that's the only option to me at this point that I can afford and I don't really want to wait 2-3 months for the 2017's to start hitting the floor.
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drwelby
shiggy wrote:
I disagree with the majority of their claims in that piece, from chainline to braking forces. Agree with heel clearance, but that is only a problem with chainstay mounted calipers and poorly designed frames.


I remember at least one custom builder getting burned by the chainline problem. The 135 hub pushes the small cog out far enough that when in the small/small the chain rubs on the large chainring. Yes, the simple answer is don't ride in the small/small, but you can't tell that to the customer who just spent several thousand dollars on their perfect dream bike.
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shiggy
drwelby wrote:


I remember at least one custom builder getting burned by the chainline problem. The 135 hub pushes the small cog out far enough that when in the small/small the chain rubs on the large chainring. Yes, the simple answer is don't ride in the small/small, but you can't tell that to the customer who just spent several thousand dollars on their perfect dream bike.
i just lost a long reply. Short version: I would tell the customer EXACTLY that. Current production chainlines are driven by factors other than drivetrain efficiency.

Nearly every bike I own has a proper chainline: chainring centerline aligned with cassette centerline.
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Nubster
Bike ordered. Has 135 rear. I will be having a new wheel set built and plan on going with a 135x10 hub so while not quite the same as the 142x12...at least I can get a little benefit from a thicker axle and supposedly better clamping.
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Mudge
drwelby wrote:


I remember at least one custom builder getting burned by the chainline problem. The 135 hub pushes the small cog out far enough that when in the small/small the chain rubs on the large chainring. Yes, the simple answer is don't ride in the small/small, but you can't tell that to the customer who just spent several thousand dollars on their perfect dream bike.


Every bike I own, or have ever owned, road, 'cross, mtb, well, not my fixie or track bike, but otherwise every bike has always suffered the 'chain rubs the big ring in small/small' problem. I'd be concerned if my bike didn't have that (non) problem
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