is thss fork steerer stem too far up the steerer tube

[gerrymcm]

I wonder if I can ask for some opinions please.
when I bought my On One Pompetamie approx 3 years I dithered about getting the steerer tube cut as I was tinkering with the setup.
A chap in my local bike shop said "I'd advise a steerer clamp until you've decided". It's now been like this for 3 years and I'd quite like to keep it at this height but recently when back in the same shop the new mechanic said "that's dangerously high up the steerer tube and will snap".

I assumed that modern heavy duty cromo forks with thick steerer tubes would be able to handle this sort of thing and that only the headset was under undue pressure with this sort of setup.
I still have the steerer clamp in place (right above the headset) and I have approx 150mm between the clamp and the bottom of my stem.

Is this too much?

Your advice would be greatly appreciated.

Sorry not a great snap due to the angle.

Thanks
Gerry

[b1ke]

I've got a Thorn Raven Sport Tour with uncut steerer and lots of spacers. Had a Thorn Sherpa with the same set-up before and never had any issues. That said, the head tube on that frame of yours looks very short so wouldn't like to say one way or the other. Why not contact Planet X with the same pic and get their advice?

[Erudin]

I can't see any problem if the steerer is steel, Surly and Thorn forks have long steerers and lots of riders leave them long.

From: http://www.ridemonkey.com/threads/long-exposed-steerer-tube-legal-warranty-issue.190791/

"I'm a little surprised that I got a response from Surly on the weekend, but I did...

Steve,

We don't specify any maximum amount of stack spacers you can use. Feel free to leave the steer tube uncut and stack 'er all the way up. The steel steer tube on the Surly fork is not even going to flinch at this. Most carbon steer tube forks and some aluminum steer tube forks will say you can't have more than x length of spacers. That ain't us. Go for it.

If your shop has questions, they're more than welcome to call. 877-743-3191

Cheers,
Eric Sovern
Surly Bikes"

[mercalia]

well what would you do if you cut it down? would you get the ride you want? If you are worried you could get a longer stem with steeper angle so that it could be used further down. I still wouldnt cut the steerer down. What sort of riding do u you do? lots of weight/thrashing on the handle bars? or a light touch?

[Valbrona]

What the hula-balula is a steerer clamp?

[gerrymcm]

Its one of these
http://www.woodmancomponents.com/Web/Pr ... 2006:27:55
They're handy when tinkering with stems as you don't have to keep checking your headset. set it once immediately above the headset and then put your spacers on top and you move spacers and stem around quickly.

Gerry

[JohnW]

Unless your saddle is lower than your bars by quite a long way, I'd say your frame is too small for you.

[Pandaz]

That's too much!!

[Pandaz]

Unless you're the worlds tallest man...!

[Erudin]

Glen Burmeister has plenty of spacers on his Raven.


From: http://glenburmeister.com/transport/

This is the bike I used to set my first three Guinness World Records.
‘Fastest cycle across Europe from North Cape to Tarifa’
‘Fastest cycle across the United States from north to south and west to east’
‘Most countries visited by bicycle in 7 days’

"To date, I have cycled over 14,000 miles on my raven tour."

[gerrymcm]

I'll try and get a snap of frame from side but handlebars aren't higher than saddle.
In fact the bike setup looks very similar to the one in the picture of Glen Burmeister's bike.
Re sizing I think I have short legs for my height and I like to maintain clearance with the top
tube. When I bought the bike I had a good long chat with the lbs (now sadly gone) and tried a bigger size
and was assured this was the size for me.
Gerry

[531colin]

I just found this on the 'net for On-One Pompetamine.....I don't know if its your year, etc, etc.

http://www.on-one.co.uk/i/q/FROOPO135/on-one-pompetamine-frame....click "size guide"

If you are looking at the difference between the 2 smallest sizes, the head tube is only 1cm longer in the larger size of those two, there is about 3cm difference between the other adjacent sizes.

The discussion on the thread seems to be getting towards "is this the right size" rather than "will the steerer break?"

......I think you would need to wrestle the bars awful hard, for an awful long time, to fatigue an un-damaged steel 1 1/8" steerer.

Whether this is the right size, or the right sort of bike, is a bigger question. You have swept bars set as high as possible, suggesting you want as upright a stance as possible.....I can't find a picture of a Pompetamine built up on On-One's site, is this what they are designed for? EDIT....I may have an answer.....https://www.google.co.uk/search?q=pompetamine+picture&rls=com.microsoft:en-GB:IE-Address&rlz=1I7SUNC_enGB402&tbm=isch&tbo=u&source=univ&sa=X&ei=P_ITVI-8KIT_PMqYgaAE&ved=0CCIQsAQ&biw=1274&bih=636

I'm not sure that a shorter stack of spacers and a high-rise stem is any different to what you have now.......the leverage exerted by the 'bar would be the same.

[Brucey]

with carbon steerers there are rules about what thickness of spacers you are and are not allowed to have in there. However with steel steerers this appears not to be the case; does anyone know of any manufacturer's 'thou shalt not under any circumstance' ruling on this? - I don't.

So what is the difference then? For one thing (if you disregard any effect from the spacers for a moment) I would argue that the bending loads in the steerer from the handlebars don't greatly vary with the exposed steerer length; the reason for this is that the top race on most A-head headsets does not provide any real resistance to bending of the steerer; all it does is locate the steerer laterally.

However once the spacers are taken into account you can see that the bending stiffness of the exposed steerer is added to by the stiffness of the spacers stack. The preload on the bearing influences this too. When the steerer sees a bending load one side of the spacer stack goes into compression and this must share the load and thus reduce the bending load in the steerer, in exchange for a slightly increased net tension load. However the greater the spacer stack, the squashier it gets; the height, all those interfaces that don't quite fit perfectly (and can slide over one another) all add up to less stiffness.

On road bikes the fashion is to use carbon spacers; I would say that many of these are pretty flimsy; you wouldn't need very many to make the stack a bit squashy. The other thing is that many carbon steerers have a special internal plug instead of a star fangled washer; the plug is often longer than you might expect, and it is intended to reinforce the steerer internally, at least as far as the top race of the headset.

So there may be a real effect arising from the spacer stack and there may be another effect that really only applies to certain carbon steerers... between the two you could see how someone in an LBS could get confused or just want to play it safe.

Overall I agree with Colin's assessment of its likely durability.

If the OP is truly concerned about the consequences of steerer failure, I'd suggest fitting a Head lock type arrangement, in which there is a long bolt that passes through the entire steerer. If the steerer should fail (which I do not think is likely), the bolt will at least hold everything together well enough for you to have a good chance to bring the machine to a safe halt. A possible snag with this scheme is that it is very easy to apply excessive preload to the headset this way.

cheers

[531colin]

Just as an aside, the OP says he has a clamp just above the headset so he can play with the spacer stack without re-adjusting the headset each time..

....so in theory his spacer stack doesn't need to be under any compressive load from the top cap....indeed, the spacers could be removed......
I still don't think his 1 1/8" steel steerer is likely to come away in his hands anytime soon.......

[gerrymcm]

Thanks guys for your input it's more reassuring. I had been considering, now I've settled on a height for the stem, buying a bit alu tubing and cutting it to length with the aim of replacing all the individual spacers. Wood this help or hinder the stresses on the steerer tube? My guess is that it could only help as it would assist in making the steerer more rigid but I know it wouldn't help if the steerer did actually snap.
Thanks
Gerry