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Seat//Head tube coplanarity

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Seat//Head tube coplanarity

Old 09-23-19, 04:17 PM
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Seat//Head tube coplanarity

What are the relevant tolerances for head tube and seat tube coplanarity?

Seat and head tubes are supposed to be in the same plane; I have a couple of bikes here where they appear to be about 1.5° out of plane.
  • What (if anything) does ISO 4210 have to say about this?
  • what are reasonable mass production tolerances?
  • what is considered acceptable by end users?
  • at what stage does this become a safety issue?
To put this in perspective, 1.5° puts the contact patches about 20mm out of line, misalignment is clearly visible when sighting along the wheels and easily measurable by several DIY methods including using straight edges and a laser level.
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Old 09-23-19, 04:31 PM
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What's really important is that the wheels are in plane. If the seat tube is out that's not nearly as important.

Here is a good thread about alignment...https://www.bikeforums.net/framebuil...-thoughts.html
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Old 09-23-19, 04:53 PM
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20mm at the contact patch is not the seat tube, unless the notion is that the rear axle is perpendicular to the seat tube. However, this is doubtful. I'm sure there are tons of bikes out there that are that bad and being ridden every day without any issue. The thing that I have found for bikes that are out of plane is that they will shimmy violently at low speed if ridden no hands. Most people don't ride no hands though.
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Old 09-23-19, 05:37 PM
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Over about 12" I aim for .020" or less variance between the ST and HT. This spec is a floating goal though as the tubes are not as straight or round as many assume and it's not the HT's outsides that counts, it's the headset's fit within the HT that should really be the datum surface.

I came to this spec after I got a surface plate and dial indicators. But being able to "measure" a thou. doesn't make it always relevant. The way wheels are installed and their offnesses are far more drift then the frames I make.

As to what others do- Many builders won't state their tolerances, why do so and give ammo to be called on? So to with most manufacturers. Andy
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Old 09-23-19, 06:32 PM
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Originally Posted by unterhausen View Post
20mm at the contact patch is not the seat tube, unless the notion is that the rear axle is perpendicular to the seat tube. However, this is doubtful. I'm sure there are tons of bikes out there that are that bad and being ridden every day without any issue. The thing that I have found for bikes that are out of plane is that they will shimmy violently at low speed if ridden no hands. Most people don't ride no hands though.
I know it is not the seat tube; the rear wheel and seat tube are coplanar, therefore the rear axle IS perpendicular to the seat tube. This is a hardtail MTB, with Boost through axles (not dropouts). The issue is the head tubes appear to be ~1.5° misaligned to the seat tube (and hence the rest of the bike frame).

Likewise. I'm sure there are many bikes that are bad and few people notice; doesn't make it acceptable, or without issues though.

However, what is the acceptable tolerance for a brand new bike from a major manufacturer? Pretty sure 1.5° ain't even close...
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Old 09-23-19, 06:38 PM
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Originally Posted by Nessism View Post
What's really important is that the wheels are in plane. If the seat tube is out that's not nearly as important.
The wheels are not in plane. They are 15mm different over 600mm diameter measured top to bottom. The rear wheel is in plane with the seat tube.
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Old 09-23-19, 06:47 PM
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Originally Posted by Andrew R Stewart View Post
Over about 12" I aim for .020" or less variance between the ST and HT. This spec is a floating goal though as the tubes are not as straight or round as many assume and it's not the HT's outsides that counts, it's the headset's fit within the HT that should really be the datum surface.

I came to this spec after I got a surface plate and dial indicators. But being able to "measure" a thou. doesn't make it always relevant. The way wheels are installed and their offnesses are far more drift then the frames I make.
Okay, I accept that for a fully built bike there will be larger tolerances, and of course this also eliminates the variation on HT bearings actual fitment. BTW the HT is tapered anyway, as is the steerer tube.

But I'm seeing a different in angle of 15mm over 600mm wheel diameter (top and bottom) which is a tad more than the tolerance you aim for. :-(

Originally Posted by Andrew R Stewart View Post
As to what others do- Many builders won't state their tolerances, why do so and give ammo to be called on? So to with most manufacturers. Andy
That's why we have standards, and why I asked if ISO 4210 happens to address this (and other tolerances).
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Old 09-23-19, 08:17 PM
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hindesite- I'll say that your frame is "a tad more" then my stated alignment tolerance. Like by about 15 times more...

First we need to go back to the foundation of why we have bikes, to ride. So is this frame exhibiting any issues with the ride? When ridden no handed is it not tracking straight, you have to lean significantly to the one side to maintain a straight line? Of course stuff like wheel dish is already pretty good?

Next there's the question as to how this 15mm was measured. If it's with a fork in situ then the fork must be checked. I certainly have seen many production forks that are rather bad in their blade length equaliness as well as the dropouts (or drop throughs) that are not centered WRT the steerer. If the 15mm was a calculated amount based on an angular HT offness please explain your method to come to this angle.

Not trying to say you can't measure or don't understand this stuff but a number stated with little/no backround as to where it was derived from isn't a full story.

While not really vital to the question of alignment one does wonder about the brand/builder of this frame. Maybe at some point you will fill us in on that aspect too. Might explain some motivations or fears.

As to the ISO standards- It was my belief that the ISO set performance and safety standards and "graded" the bikes/frames on tests that place loads and measured deflections or ran the structures through fatigue tests to failure. I don't recall any alignment (under load or not) aspects being talked about when this standard was being designed or enacted. So I tried to pull up the standards actual text and have to pay for it. (Although in this day and age of intellectual rights being stolen and offered on line for free there is likely some place I could find the standards for free. Not that I plan to do that as I respect others hard work at this kind of thing). So I really can't speak with self authority about whether ISO 4210 is applicable here.

Some in reading my reply here might see me as a downer and a person who is too picky as to terms and maybe anal (auto censor might nix that word) about how people converse. If so I can handle that claim. I prefer to think I view these questions as a complex problem with various levels and relationships and am trying to cut through the miss directions or lacking info to get to the roots and therefore end up with a greater understanding of the problem.

This thread's trajectory that is an example of why so many don't publish alignment specs. I would love to have your frame in my hands for an evening. If what you say is real it's a sad example of a quality built frame. But we are not the ones that count. Andy
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Old 09-23-19, 09:25 PM
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what I see online is that the ISO spec in question is 6 pages. Somehow I doubt there is anything more than fluff in a spec that short, but I'll see if I can get a look at it.

I don't know what would happen if you went to a major bike company with a complaint that a frame didn't meet an ISO standard. Good luck with that.
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Old 09-24-19, 10:15 AM
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"I don't know what would happen if you went to a major bike company with a complaint that a frame didn't meet an ISO standard."

As far as I know, meeting ISO standards is voluntary, not mandatory, so as unterhausen said, "Good luck with that."
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Old 09-24-19, 03:16 PM
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Originally Posted by unterhausen View Post
what I see online is that the ISO spec in question is 6 pages. Somehow I doubt there is anything more than fluff in a spec that short, but I'll see if I can get a look at it.

I don't know what would happen if you went to a major bike company with a complaint that a frame didn't meet an ISO standard. Good luck with that.
Part 1 of the standard is 6 pages, and covers terms and definitions. There are 9 parts covering various aspects of the standard, most appear to cover test methods but also minutiae like spoke protectors.

Of most interest here is Annex A to Part 2, which covers steering geometry.

There are numerous other standards related to cycles, some of them are incredibly specific (like the standard for stem wedge angles!) but I can't see anything that covers the basics like wheel trueness, frame alignment etc.

From a Medium article titled "Electric Bikes: standards, laws and safety concerns":

The TC149 ISO bicycle committee, including the TC149/SC1 («Cycles and major sub-assemblies») subcommittee, has published the following standards:[citation needed]
  • ISO 4210 Cycles – Safety requirements for bicycles
  • ISO 6692 Cycles – Marking of cycle components
  • ISO 6695 Cycles – Pedal axle and crank assembly with square end fitting – Assembly dimensions
  • ISO 6696 Cycles – Screw threads used in bottom bracket assemblies
  • ISO 6697 Cycles – Hubs and freewheels – Assembly dimensions
  • ISO 6698 Cycles – Screw threads used to assemble freewheels on bicycle hubs
  • ISO 6699 Cycles – Stem and handlebar bend – Assembly dimensions
  • ISO 6701 Cycles – External dimensions of spoke nipples
  • ISO 6742 Cycles – Lighting and retro-reflective devices – Photometric and physical requirements
  • ISO 8090 Cycles – Terminology (same as BS 6102–4)
  • ISO 8098 Cycles – Safety requirements for bicycles for young children
  • ISO 8488 Cycles – Screw threads used to assemble head fittings on bicycle forks
  • ISO 8562 Cycles – Stem wedge angle
  • ISO 10230 Cycles – Splined hub and sprocket – Mating dimensions
  • ISO 11243 Cycles – Luggage carriers for bicycles – Concepts, classification and testing
Other ISO Technical Committees have published various cycle relevant standards, for example:
  • ISO 5775 Bicycle tire and rim designations
  • ISO 9633 Cycle chains – Characteristics and test methods
Published cycle standards from CEN TC333 include:
  • EN 14764 City and trekking bicycles – Safety requirements and test methods
  • EN 14765 Bicycles for young children – Safety requirements and test methods
  • EN 14766 Mountain-bicycles – Safety requirements and test methods
  • EN 14781 Racing bicycles – Safety requirements and test methods
  • EN 14782 Bicycles – Accessories for bicycles – Luggage carriers
  • EN 15496 Cycles – Requirements and test methods for cycle locks
Yet to be approved cycle standards from CEN TC333:
  • EN 15194 Cycles – Electrically power assisted cycles (EPAC bicycle)
  • EN 15532 Cycles – Terminology
  • 00333011 Cycles – Bicycles trailers – safety requirements and test methods
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Old 09-24-19, 05:45 PM
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Originally Posted by TiHabanero View Post
"I don't know what would happen if you went to a major bike company with a complaint that a frame didn't meet an ISO standard."

As far as I know, meeting ISO standards is voluntary, not mandatory, so as unterhausen said, "Good luck with that."
I think that is not being fair to the manufacturers, they very well may take issues raised seriously, I know the manufacturer in my case has.

I would think in any case a cycle that fails an ISO 4210 specified safety test is going to be a legal liability for any manufacturer/distributor/retailer and each may put pressure to fix the situation.
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Old 09-24-19, 06:11 PM
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Originally Posted by hindesite View Post
I think that is not being fair to the manufacturers, they very well may take issues raised seriously, I know the manufacturer in my case has.

I would think in any case a cycle that fails an ISO 4210 specified safety test is going to be a legal liability for any manufacturer/distributor/retailer and each may put pressure to fix the situation.
It doesn't work that way. ISO creates standards, it does not mandate their application.
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Old 09-24-19, 06:58 PM
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Originally Posted by Nessism View Post
It doesn't work that way. ISO creates standards, it does not mandate their application.
Please go back and read what I wrote; I did not say that ISO mandates anything. It does, however, give parties a common baseline to work from. It also provides tools for organisations to build their own processes on. It can be used by regulators to enforce (in this case) safety standards rather than every jurisdiction creating their own.

In any case it is not my intention to focus on ISO 4210 particularly, but more about what is acceptable tolerances for frame defects (in this case, head/seat tube misalignment).
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Old 09-24-19, 07:20 PM
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nobody is going to mandate head tube/rear axle axis misalignment. I doubt anyone considers it a safety issue. A specification for this requires a fairly sophisticated tolerancing which is not the kind of thing found in standards. For example, old style +/- dimension tolerancing doesn't work. It would require GD&T, and those are very difficult to produce in the abstract.

This is a forum for framebuilders, not people who mass produce frames. Most companies that mass-produce frames do have their own tolerances, some of them fairly wide. I know my LBS has gotten warranty replacements of bikes because there were alignment problems with the frames. The one case I'm aware of is the dropouts not being parallel within a reasonable tolerance.

What is your role in the purchase/sale of these bikes? If you have recourse, I would ask for a warranty replacement. If you are a reseller working with a factory, you need to work on your specifications.
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Old 09-25-19, 07:28 PM
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Originally Posted by unterhausen View Post
nobody is going to mandate head tube/rear axle axis misalignment.
Of course they are, even if only internally to the manufacturer.

I doubt anyone considers it a safety issue.
I bet you'd consider it a safety issue if the contact patch was 100mm misaligned. How about 50mm? 25mm?

A specification for this requires a fairly sophisticated tolerancing which is not the kind of thing found in standards. For example, old style +/- dimension tolerancing doesn't work. It would require GD&T, and those are very difficult to produce in the abstract.
Just because it might be hard doesn't mean it isn't done; but that is irrelevant. I'm specifically asking about what reasonable expectations are.

This is a forum for framebuilders, not people who mass produce frames.
I understand that, but I'm sure people here will have made frames for customers, and wonder how they deal with this issue.

Most companies that mass-produce frames do have their own tolerances, some of them fairly wide.
I doubt that you are being fair to manufacturers with an opinion like that, unless you have some specific examples.

I know my LBS has gotten warranty replacements of bikes because there were alignment problems with the frames. The one case I'm aware of is the dropouts not being parallel within a reasonable tolerance.
You've just coasted past my question. Would you circle back and explain just what "reasonable tolerances" were?

What is your role in the purchase/sale of these bikes? If you have recourse, I would ask for a warranty replacement. If you are a reseller working with a factory, you need to work on your specifications.
Do you think that a spec might include some kind of tolerance for head/seat tube alignment?

Neither is relevant or what I was asking about; in fact warranty replacement is a given, the retailer and factory are both taking this very seriously.
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Old 09-25-19, 08:03 PM
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Originally Posted by Andrew R Stewart View Post
hindesite- I'll say that your frame is "a tad more" then my stated alignment tolerance. Like by about 15 times more...

First we need to go back to the foundation of why we have bikes, to ride. So is this frame exhibiting any issues with the ride? When ridden no handed is it not tracking straight, you have to lean significantly to the one side to maintain a straight line? Of course stuff like wheel dish is already pretty good?
Thanks Andrew, you are the only respondent here who has addressed any of my questions.

Wheels are perfectly true and exactly centered on the seat tube and between the fork stanchions, so I'm sure wheel dish is correct. Besides, the issue isn't offset, if is an angular error. Not easy to ride no hands, and front wheel has a tendency to wash out to the left in mud and gravel. On seal you are slightly aware of having to correct the steering. When you look down you get the impression the front tire is not parallel to the top tube.

Next there's the question as to how this 15mm was measured. If it's with a fork in situ then the fork must be checked. I certainly have seen many production forks that are rather bad in their blade length equaliness as well as the dropouts (or drop throughs) that are not centered WRT the steerer. If the 15mm was a calculated amount based on an angular HT offness please explain your method to come to this angle.

Not trying to say you can't measure or don't understand this stuff but a number stated with little/no backround as to where it was derived from isn't a full story.
The fork looks perfect, the wheel is centered and there is no evidence of a bent steerer tube. I could I guess also measure how parallel the fork tubes are to the rear wheel, or rotate the fork 180° but at this stage doesn't seem likely to be the problem.

I used 4 different methods to assess the problem with the bike upside down and the steering set straight;
  • eyeball,
  • single straight edge run across rear and front wheels,
  • a vertical straight edge on a chord across each wheel, and measured the end points wrt a vertical laser plane
  • set laser plane parallel to the rear wheel rim, measure offsets to laser at the 4 quadrants of each wheel rim (to eliminate tire variables)((top, bottom, front, rear) and also the seat tube.
I believe my methods are solid considering they were done at home with nothing special; the manufacturer's response was: "The evidence of misalignment is overwhelmingly convincing" :-)

I can't post images at this stage but will do so when able.

While not really vital to the question of alignment one does wonder about the brand/builder of this frame. Maybe at some point you will fill us in on that aspect too. Might explain some motivations or fears.
No, I don't think it is appropriate to do that at this stage, and in any case isn't relevant to my quest for what acceptable tolerances and expectations are. I'm surprised that for such a basic attribute of frame accuracy so many people are dismissive of its importance.

As to the ISO standards- It was my belief that the ISO set performance and safety standards and "graded" the bikes/frames on tests that place loads and measured deflections or ran the structures through fatigue tests to failure. I don't recall any alignment (under load or not) aspects being talked about when this standard was being designed or enacted. So I tried to pull up the standards actual text and have to pay for it. (Although in this day and age of intellectual rights being stolen and offered on line for free there is likely some place I could find the standards for free. Not that I plan to do that as I respect others hard work at this kind of thing). So I really can't speak with self authority about whether ISO 4210 is applicable here.

Some in reading my reply here might see me as a downer and a person who is too picky as to terms and maybe anal (auto censor might nix that word) about how people converse. If so I can handle that claim. I prefer to think I view these questions as a complex problem with various levels and relationships and am trying to cut through the miss directions or lacking info to get to the roots and therefore end up with a greater understanding of the problem.

This thread's trajectory that is an example of why so many don't publish alignment specs. I would love to have your frame in my hands for an evening. If what you say is real it's a sad example of a quality built frame.
It is worse that that; this is 2 almost consecutive frames, both exhibiting exactly the same problem, with only 1 serial number between them. Who knows what else is wrong with these frames...
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Old 09-25-19, 09:02 PM
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Sorry to say but your measurement method wouldn't pass muster under an ISO environment, so it would be hard to argue the ISO game if you can't provide data on that level. Regardless, your post is confusing if on one hand you want us to define acceptable alignment tolerances, and then on the other hand you indicate that the manufacturer shares your feeling that the frame is misaligned? Is this a case of you having a beef with a frame manufacturer that won't warranty your frame (2nd one?) because of misalignment? Does the frame manufacturer carry an ISO cert? What do they say is an acceptable level of misalignment?
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Old 09-25-19, 09:18 PM
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Having the "top" of the wheel centered between the blades says very little as to how the fork is/isn't aligned. One can , and some do, just file one drop out slot and presto the wheel is centered as you described. The fork could still have the drop outs off center WRT the steerer's axis. Only now many will claim the fork is fine. Your's might be, but to use the fork as the gage for alignment is just fooling one's self. Until the fork's alignment is confirmed it too is suspect given the descriptions you nicely provide. Your methods are fine up to that point. That you employed a few differing checks shows your attempts have much merit, up to the fork as a gage, and certainly don't exonerate the frame from being twisted.

One way to check the fork's alignment with no specific tools is to remove the tire/tube, the stem (if a quill) or top cap (if threadless) and reinstall the wheel. Then sight down the steerer from above looking through the rim's valve hole so you can spot the rim on the wheel's far side. If the fork's drop outs are centered WRT the steerer's axis the rim, both at it's top and far side will also be centered. Here's a post I made about this method years ago. https://www.bikeforums.net/bicycle-m...ard-right.html

Checking the main frame twist isn't too hard but does take more time. One of the issues with alignment check is knowing the method and tools are correct as well as having the frame in a state where other components don't either shadow your goal or hinder the set up. A trained eye can see some HT/ST twist if it's major and if the tubes aren't conical ( or otherwise not flat along their sides). This is why many will want to mount the frame on a known flat surface (and relying on the BB shell face as the contact point(s) isn't correct, the shell can be canted but the frame otherwise not twisted. It will track straight but the rider will be "off" in the pedaling) and measure the ST parallelness to the surface then that of the HT. This is where I get my .020" per aprox foot spec.

But all this is now known to be moot as the shop and manufacturer seems to agree that the frame is out of spec. At least they seem to be doing the right thing. After this is all done and over you might ask the shop or manufacturer if it's OK to share names. If so then praise them for their willingness to make things right.

As to what else is good/bad? Who knows? We don't. I do suggest having any replacement frame/fork checked for alignment (and other visible issues) before it's being built up and ridden. If the shop doesn't like this suggest it might be time to out them. Remind them that your only goal is a satisfactory frame/fork, not vengeance but that enough is enough. Were this to get to this point where I work I would invite you to my basement and we could collective explore the alignment and go from there. Andy
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Old 09-25-19, 09:23 PM
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Originally Posted by Nessism View Post
Sorry to say but your measurement method wouldn't pass muster under an ISO environment, so it would be hard to argue the ISO game if you can't provide data on that level. Regardless, your post is confusing if on one hand you want us to define acceptable alignment tolerances, and then on the other hand you indicate that the manufacturer shares your feeling that the frame is misaligned? Is this a case of you having a beef with a frame manufacturer that won't warranty your frame (2nd one?) because of misalignment? Does the frame manufacturer carry an ISO cert? What do they say is an acceptable level of misalignment?
I strongly suspect that the manufacture just wants to put this behind them. I doubt their US shipping "office" has any ability to measure alignment, very few do. While the OP's methods are not completely fool proof they do provide enough info in how the OP has tried to deal with this. This amount of effort alone warrants the manufacturer listen and decide, independent of the methods, whether loosing a customer (and potentially getting outed on social sites) is worth the cost of another frame. At some point their decision becomes a business one, not a framebuilding one. Andy
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Old 09-26-19, 03:28 PM
  #21  
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Originally Posted by Andrew R Stewart View Post
I strongly suspect that the manufacture just wants to put this behind them. I doubt their US shipping "office" has any ability to measure alignment, very few do. While the OP's methods are not completely fool proof they do provide enough info in how the OP has tried to deal with this. This amount of effort alone warrants the manufacturer listen and decide, independent of the methods, whether loosing a customer (and potentially getting outed on social sites) is worth the cost of another frame. At some point their decision becomes a business one, not a framebuilding one. Andy
In this case my assessment is that the manufacturer is taking this very seriously, and not looking at it as not losing a customer or dealing with social media fallout. I've had communications from the team lead and one of the product engineers directly; I'm pretty sure they are worried they have a systemic problem as for such a large defect to appear on 2 nearly consecutive frames carries implications for their entire supply chain, not just this model (and size of course). Likewise there are ramifications for the entire retail/distribution chain, since retailers are directly responsible to the customer for fixing this.

In this context the cost (to them) of a replacement frame is truly insignificant.

It isn't so insignificant to me, of course.
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Old 09-26-19, 03:35 PM
  #22  
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Originally Posted by Andrew R Stewart View Post
Having the "top" of the wheel centered between the blades says very little as to how the fork is/isn't aligned. One can , and some do, just file one drop out slot and presto the wheel is centered as you described. The fork could still have the drop outs off center WRT the steerer's axis. Only now many will claim the fork is fine. Your's might be, but to use the fork as the gage for alignment is just fooling one's self. Until the fork's alignment is confirmed it too is suspect given the descriptions you nicely provide. Your methods are fine up to that point. That you employed a few differing checks shows your attempts have much merit, up to the fork as a gage, and certainly don't exonerate the frame from being twisted.
I'm almost certain the forks on both bikes are good; these are air forks with 34mm stanchions, and being Boost 110 they have a 15mm through axle which passes through both fork ends perfectly. The fork suspension moves freely with no sticking. The likelihood of the forks themselves being wrong is not high, the most likely unknown is the steerer tube, and since these are tapered the lower bearing flanges are quite wide, the gap appears perfectly even and very tight all around the circumference so I'm confident the steerer is also straight.
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Old 09-26-19, 05:26 PM
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Originally Posted by Nessism View Post
Sorry to say but your measurement method wouldn't pass muster under an ISO environment, so it would be hard to argue the ISO game if you can't provide data on that level.
Great, we are in complete agreement on that point.

What I have done is move from saying "Well, I think the frame is twisted" to "the frame looks this twisted" to "I have measured to the best of my ability the twist in the frame, and it is about this much".

Regardless, your post is confusing if on one hand you want us to define acceptable alignment tolerances, and then on the other hand you indicate that the manufacturer shares your feeling that the frame is misaligned?
While you may be confused, I don't see my post as being confusing. I have identified a significant issue with 2 frames, and that is being dealt with. Which naturally leads to the entirely separate question "just what is the acceptable tolerance for this attribute", which happens to be one of the most basic and fundamental functions of the frame. Yet nobody can tell me.

Is this a case of you having a beef with a frame manufacturer that won't warranty your frame (2nd one?) because of misalignment?
No, that is completely unfounded and incorrect speculation on your part; the retailer and manufacturer have been excellent in dealing with this, I have zero complaints or issues there.

Does the frame manufacturer carry an ISO cert?
As it happens, the frame does have a rather prominent large transfer saying "ISO 4210 Tested" :-)


What do they say is an acceptable level of misalignment?
They don't. I was hoping ISO 4210 did. That is why I'm asking the experts round here. It also happens to be the only question I'm asking - see my OP.
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Old 09-26-19, 06:37 PM
  #24  
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Originally Posted by hindesite View Post
I'm almost certain the forks on both bikes are good; these are air forks with 34mm stanchions, and being Boost 110 they have a 15mm through axle which passes through both fork ends perfectly. The fork suspension moves freely with no sticking. The likelihood of the forks themselves being wrong is not high, the most likely unknown is the steerer tube, and since these are tapered the lower bearing flanges are quite wide, the gap appears perfectly even and very tight all around the circumference so I'm confident the steerer is also straight.
With more info come more understanding. However there's many suspension forks that are not well aligned. The media hype of through axle constructs make it seem they can't suffer from issues. Again, trust but verify. Andy
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Old 09-26-19, 06:59 PM
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Originally Posted by hindesite View Post
Great, we are in complete agreement on that point.

What I have done is move from saying "Well, I think the frame is twisted" to "the frame looks this twisted" to "I have measured to the best of my ability the twist in the frame, and it is about this much".



While you may be confused, I don't see my post as being confusing. I have identified a significant issue with 2 frames, and that is being dealt with. Which naturally leads to the entirely separate question "just what is the acceptable tolerance for this attribute", which happens to be one of the most basic and fundamental functions of the frame. Yet nobody can tell me.



No, that is completely unfounded and incorrect speculation on your part; the retailer and manufacturer have been excellent in dealing with this, I have zero complaints or issues there.



As it happens, the frame does have a rather prominent large transfer saying "ISO 4210 Tested" :-)




They don't. I was hoping ISO 4210 did. That is why I'm asking the experts round here. It also happens to be the only question I'm asking - see my OP.
Bust open the piggy bank and purchase the ISO standard. A quick google search suggests it's about safety standards, not about alignment. And while yes alignment can affect control of the bike I doubt that's what the standard focuses on. The only way to know for sure is to read the standard though.

And BTW, your posts ARE confusing. It's clear that you have an ulterior motive for this thread. Why not just come out and say it?
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