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Steerer tube extension - is it safe?

66K views 52 replies 26 participants last post by  Lombard 
#1 ·
I was in the LBS this afternoon. This guy came in with this really nice road bike that he bought online for a great deal. The bike was really nice.

He was an older, heavier guy, and I think this may have been a race bike. He was having troubles with fit (go figure, but he got a great deal on the bike).

The LBS staff was trying to install a steerer tube extension on the bike. It was a carbon frame, carbon fork, but the fork had an aluminum steerer tube. I watched the LBS guy putting it on, and I asked:
(Me, asking tentatively) - "Is that safe?"
(LBS guy, answering confidently) - "Oh, it's very safe."
(Me) - "I don't think it is."

I went and mentioned to the store manager that those steerer tubes are limited to about 5 cm extension, or else the torque on them could crack them and cause a failure. I asked him to go back and investigate, then I left.

Are those steerer tube extensions safe?
 
#8 ·
But it's not safe from ridicule.

Those extenders belong on comfort bikes, not race bikes.
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#9 ·
I had an similar experience. My son plays High School Football and the head coach called a running play on 3rd &10. I thought a passing play was in order. So I called the athletic director at home and told him he might want to come to the game cause the coach isn't calling the proper plays.
 
#12 ·
Sometimes I think this is some kind of joke. And then I realize it isn't.

Is that a Trek?
 
#16 ·
Omg

that big "N" on his jersey is for NO NO NO NO NO NO!!

However, back to the OP's concern, no there isn't inherently anything UNsafe about a steerer extension. On the other hand, I would have no hesitation as a shop employee to tell him that:
A: no matter how 'good a deal' the big is, it is not the right bike for him, and
B: IF the mechanic says "ok" It will cost you at least $100 for us to install (new cables, housing, bar tape, yada yada)
C: Frankensteining that bike will affect handling,
D: We would ask that you sign this dated letter absolving us from all liabilty

I've had this conversation in the past with a customer, and they ended up returning the "good deal" bike and bought a more appropriate and properly fitting bike from us.

Had a similar conversation with a gentleman who had a 60cm Madone with a steerer extension. Our conversation ended with him putting down a deposit with me for a custom Moots.

So, my point is that the LBS is doing a disservice to the customer by:
A: NOT selling him/her on the expertise, knowledge and services of their shop,
B: Allowing him/her to have a crappy experience on a bike. That, I think, is the worst part of it all. :cryin:
 
#17 ·
Is it safe? probably yes.

Total bending moment on the extended steerer is a function of stack height and handlebar extension. The measurement that counts is the distance from the handlebar to the headset top assembly. There are other factors involved including how precisely the spacers are made, and the angle that the rider pulls on the bars.

In any case, the extender fits down into the steerer and reinforces it pretty well. If the base of the extender is below the headset bearing the arrangement is probably stronger than direct mounting.

If the bottom is above the headset, it's the same as without except for the longer moment arm, but with a short stem and a rider who doesn't work the bars hard hill climbing is probably no worse than the use of carbon parts anywhere else on the bike.
 
#18 ·
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.
 
#30 ·
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.
 
#23 ·
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 ?
 
#26 ·
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?
 
#37 ·
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.'
 
#42 ·
Step one: Find an online seller with a wide selection. Someone that stocks from QBP will do.
Step two: Notice that these are available from multiple manufacturers.
Step three: Consider America's litigious environment.

They may not be the best idea on the planet, for a few reasons, but yeah, they are reasonably safe when used according to directions.
 
#43 ·
This is an old thread and I noticed no one here has actually installed or used a steerer extension. Good news! I have one on an aluminium frame Malvern Star oppy A4. The stock frame is very racey (small headtube). Bike is a lot more comfortable and the geometry is now more like an endurance bike when on the hoods and of course you still have the drops when you need some speed. This was my first race bike and I bought the large size (56cm top tube) on the recommendation of the bike shop owner. I'm 185cm tall and 55 when I bought it. I have also installed a shorter stem so no problem with cables. In retrospect a more comfortable geometry would have been the way to go but because of my inexperience I didn't know any better. I assumed race bikes were meant to be uncomfortable!
Extender works fine and is solid. I've completed 100km plus rides on this bike without any problems.
479059
 
#47 ·
A stem extender is OK unless you have a carbon steerer, then it's dangerous. If you are looking to get some handlebar height, why are your bars tilted so low. You can get "free height" by tilting them up. Better yet, get bars with a shorter reach and a stem with a greater rise.

This being said, as Finx said, the bike looks too small for you anyway. These "fixes" are all a Band-Aid on a broken leg.

And as duriel implied, your saddle angle looks like you would struggle to not slide forward. I can't imagine that's very comfortable.
 
#51 ·
Looks like he was re-banned already. Don't know what he posted elsewhere. These two posts of his don't seem ban worthy.
 
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