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So nothing about this situation raises any red flags for you? Would you have risked your bottom line and reputation on the safety of that deal?
Yes, so far there is nothing about this that raises a red flag for me. As it stands now, I don't have enough information to second guess the judgement of the mechanic in the field. It's possibly that he's going too far, and it's equally possible that it's perfectly safe. the devil here is in the details.

It's always easy to say something may be unsafe. After all there's no way to determine the consequences of an accident that might have happened. Following that logic to it's conclusion nothing is safe, so we need to make judgement calls. And those need to be based on real information about the particulars.
 

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Discussion Starter #22
There are two issues here:

1. Is this safe? On an aluminum steerer, probably.

2. Do you have the depth of knowledge to tell professionals how to do their job? See 1.


You can only argue the ethics of speaking up if you actually have the information to speak up about. If not, you are being a busybody.

Illustrated:
We had a customer buy a $5000 bike the other day. When asked if he wanted a lighter wheel option, he told the mechanic that lighter wheels make the bike less stable, since bikes are kept upright by centrifugal force (they aren't). Imagine if he started doing his 'ethical duty' by warning someone else in the store looking at light wheels to avoid them?

His microscopic bit of knowledge on the topic is fine for him to act on, but screwing with other people's bikes and jobs is not.
I bet you work at "Cycling Spoken Here". Am I correct?
 

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Thank goodness Navy Beat Army yesterday, else this photo would have ruined the rest of 2011 for me.

On a serious note, I was at my local LBS today and one of the wrenchers there has about a 3" extension above the stem on his bike. Is he just "borrowing" a stem and doesn't want to cut It ?
 

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Cathedral City, CA
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Just out of curiosity, I would say that this issue is not a bike fit problem. It sounds more like a rider flexibility problem and they are trying to get the bike to work around that. Anybody else read it this way?
 

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A steerer stack limit of 4cm is generally accepted for carbon steerers. Steel steerers don't really have a limit, and aluminum is a relative unknown. But aluminum should be stronger than carbon for clamping.

What lead you to believe you knew better than the shop staff?
Because most shop staff are not engineers, that's why...
 

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That's irrelevant. :confused:

No one in this story is an engineer. The people who are the engineers are the ones who made the fork and the extensions and wrote the installation manuals that the mechanics read.
I didn't know that bike shop mechanics could read? ....

oooooh.. just kidding, just kidding, I couldn't resist.

But seriously I have seen some awful stuff happen at the hands of bike shop mechs. Awful awful things... I now do everything myself.:thumbsup:
 

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This definitely wasn't a power rider. He was an old, overweight yuppie who got a good deal on a closeout boutique bike online. He had the shop build it from the box for him.The extender would have been mounted above the spacer and headset stack, probably 5cm above the headset.
The stem was probably 100 - 110 mm, 0-6 degree rise.

I'm sure there was no discussion on changing some of the easier variables such as stem length and rise first. The customer probably told the sales guy about what he wanted, and the sales guy tried to accommodate the guy without having him get on a bike and see.

I wanted to step in and tell the guy that was the wrong bike for him, but it just wasn't my place. I'll probably find that bike on Craigslist within the next year.
You seem to know an awful lot about this transaction including the customers ability level, social standing, where he got the bike, etc. Just be aware of all the assumptions you're making.
The stem was probably...
I'm sure there was no....
The customer probably....
I bet you work at.....

You need more information, less disinformation, and more experience before you go around telling shop mechanics how to do their job. It interferes with their work and it can get you a reputation as a pain in the ass. Then you get disillusioned when you go into the shop and get no attention, no service, no deals, and no advice.
 

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Discussion Starter #31
You seem to know an awful lot about this transaction including the customers ability level, social standing, where he got the bike, etc. Just be aware of all the assumptions you're making.
The stem was probably...
I'm sure there was no....
The customer probably....
I bet you work at.....

You need more information, less disinformation, and more experience before you go around telling shop mechanics how to do their job. It interferes with their work and it can get you a reputation as a pain in the ass. Then you get disillusioned when you go into the shop and get no attention, no service, no deals, and no advice.
Speaking of assumptions, everyone is assuming that this was the MECHANIC helping the guy. It WAS NOT. It was a member of the SALES FLOOR staff. A CASHIER.
 

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Discussion Starter #32
That's irrelevant. :confused:

No one in this story is an engineer. The people who are the engineers are the ones who made the fork and the extensions and wrote the installation manuals that the mechanics read.
I'm an engineer.

Since I'm being accused of making assumptions, I'm going to assume that if we contacted the engineers who designed the fork they would not recommend that an extension be added for a variety of reasons. Liability is probably at the top of the list.

The assembly may not fail, but if it does, the consequences could be disastrous. Better to err on the side of caution.
 

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I'm an engineer.

Since I'm being accused of making assumptions, I'm going to assume that if we contacted the engineers who designed the fork they would not recommend that an extension be added for a variety of reasons. Liability is probably at the top of the list.

The assembly may not fail, but if it does, the consequences could be disastrous. Better to err on the side of caution.
This was a 1 1/8" extension, and 1 1/8" steerer tubes are all either carbon or aluminum these days. These extensions are still being produced. Are you saying an engineer designed this, but never to be used?:confused:

BTW, nearly everybody these days is fat, and the skinny ones are not often the ones buying equipment to sit up straighter. I really don't understand who or what you think this device was built for. It isn't a candlestick.
 

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new benchmark

This is the gold standard against which all future ridiculous handlebar extensions will be measured
 

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Discussion Starter #35
This was a 1 1/8" extension, and 1 1/8" steerer tubes are all either carbon or aluminum these days. These extensions are still being produced. Are you saying an engineer designed this, but never to be used?:confused:

BTW, nearly everybody these days is fat, and the skinny ones are not often the ones buying equipment to sit up straighter. I really don't understand who or what you think this device was built for. It isn't a candlestick.
You are an argumentative type, aren't you? That's why I asked if you worked at that particular shop. I see you are in the Triangle area. I'm curious as to which shop so I can stay out of it.

Engineers can design all sorts of things, but that doesn't mean that mixing them is a good idea. Just because something is made for a bike and has a certain dimension, doesn't make it compatible.

Engineers designed clamping bike racks and clamping work stands, but that doesn't mean I can clamp them on my engineer designed carbon frame.

One engineer designed a threaded assembly and another engineer designed a tool. But if I use said tool in a manner inconsistent with the specs of the threaded assembly, it will fail. Both were designed by engineers.

So if you rig this assembly up, and it fails, who is ultimately responsible for the consequences? The folks that make the steerer tube extender? That part won't fail, unless it fails at the clamp/screw threads. The fork will be the failure point. It is being used in a manner inconsistent with how it was designed. That manufacturer will deny any claim due to this.

In case of a failure, the store will ultimately be held responsible for the bad advice.
That doesn't help our new cyclist, who should have been advised that this was the wrong bike for him and that he is better off looking for the bike that best fit him.
 

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classiquesklassieker
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You are an argumentative type, aren't you? That's why I asked if you worked at that particular shop. I see you are in the Triangle area. I'm curious as to which shop so I can stay out of it.

Engineers can design all sorts of things, but that doesn't mean that mixing them is a good idea. Just because something is made for a bike and has a certain dimension, doesn't make it compatible.

Engineers designed clamping bike racks and clamping work stands, but that doesn't mean I can clamp them on my engineer designed carbon frame.

One engineer designed a threaded assembly and another engineer designed a tool. But if I use said tool in a manner inconsistent with the specs of the threaded assembly, it will fail. Both were designed by engineers.

So if you rig this assembly up, and it fails, who is ultimately responsible for the consequences? The folks that make the steerer tube extender? That part won't fail, unless it fails at the clamp/screw threads. The fork will be the failure point. It is being used in a manner inconsistent with how it was designed. That manufacturer will deny any claim due to this.

In case of a failure, the store will ultimately be held responsible for the bad advice.
That doesn't help our new cyclist, who should have been advised that this was the wrong bike for him and that he is better off looking for the bike that best fit him.
Rather than arguing in abstract, why don't you find a fork manufacturer's instruction that states the limit that is exceeded in this case? Out of curiosity, I looked at Bontrager's fork installation document and it doesn't give any limits.

I think you are opening new fronts of argument that are not relevant to the discussion, at least I don't see how they are. I thought the argument was simply about whether a particular installation scenario is dangerous, which you helpfully suggested meant that it exceeds a specification.
 

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Just out of curiosity, I would say that this issue is not a bike fit problem. It sounds more like a rider flexibility problem and they are trying to get the bike to work around that. Anybody else read it this way?
Not so much. That's as much as saying that there should only be one size of bicycle, and everyone should just get comfortable as best as they can.

The bike should be adapted to the rider, not the rider to the bike. And if you are doing it right, the bike is close enough that only minor changes are needed.

What I read in this case is that someone simply bought the wrong size bike, because it was a 'good deal.' I wonder how many suits he has in his closet that are three sizes too small, but were a 'good deal.'
 

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You are an argumentative type, aren't you? That's why I asked if you worked at that particular shop. I see you are in the Triangle area. I'm curious as to which shop so I can stay out of it.

Engineers can design all sorts of things, but that doesn't mean that mixing them is a good idea. Just because something is made for a bike and has a certain dimension, doesn't make it compatible.

Engineers designed clamping bike racks and clamping work stands, but that doesn't mean I can clamp them on my engineer designed carbon frame.

One engineer designed a threaded assembly and another engineer designed a tool. But if I use said tool in a manner inconsistent with the specs of the threaded assembly, it will fail. Both were designed by engineers.

So if you rig this assembly up, and it fails, who is ultimately responsible for the consequences? The folks that make the steerer tube extender? That part won't fail, unless it fails at the clamp/screw threads. The fork will be the failure point. It is being used in a manner inconsistent with how it was designed. That manufacturer will deny any claim due to this.

In case of a failure, the store will ultimately be held responsible for the bad advice.
That doesn't help our new cyclist, who should have been advised that this was the wrong bike for him and that he is better off looking for the bike that best fit him.
I don't know what the Triangle area is - I'm in Wisconsin.

I also don't understand what you're getting at with the highlighted section. You said that the guy's bike had an aluminum steerer - the most conservative steerer material available in 1 1/8". If the extender wasn't for this guy's bike, who's bike is it for? Are you talking about a weight limit or bar width limit? :confused:


The other thing to consider here is that the extender connects to the steerer tube the same way a stem with no spacers does - all the way at the bottom. So if spacers are an issue, this system has none.

The only other consideration is leverage. These extenders add 7cm of height, but Mr. Pythagorus says that on a 42cm bar that only increases the lever arm from hoods to headset by 1.1cm. If the leverage of adding this extender is the same as simply going from a 42 to a 44cm bar, what is you engineering issue with it?


BTW, you posted this, not me. If you don't want an argument, don't post something wrong and then insist you're right about it.
 
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