Threadless Steering Tube Extensions?

It sounds like this a MTB. Is the steerer tube Al or Fe? Is it 1'"or 11/8"?
If it is 1 1/8" steel, the sky's the limit. Your weight and riding style
will determine the limits for Al.
I once sleeved an Al steerer w/cro-mo for a customer with few options.
Tom

--
Bruni Bicycles
"Where art meets science"
brunibicycles.com
410.426.3420
(Pete Cresswell) wrote in message
...
Maybe somebody with an engineering background can shed some light...

Seems to me like I read somewhere that the max height of a spacer stack
was
something like 1.25 or 1.5 inches - anything in excess of that was
challenging
the strength of the steering tube too much.

If that's the case, what's the diff between that and:

1) Really high riser bars - like 3". Isn't the leverage still there down
where
the steering tube goes into the headset?

2) Steering tube extensions that clamp on to the existing protrusion -
same
observation about the leverage still being there.


My agenda is that my riser bars are pretty high, and I've already trimmed
my
steering tube so it's max stack is about 1.25". If I replace those
risers and
want to keep the same bar height, I'll be faced with a choice between
getting
risers that are just as extreme and getting, say, 1" risers and elevating
the
stem attachment point (the stem's height is already max..).

Any thoughts besides getting a custom frame?
-----------------------
PeteCresswell

Maybe somebody with an engineering background can shed some light...

Seems to me like I read somewhere that the max height of a spacer stack was
something like 1.25 or 1.5 inches - anything in excess of that was challenging
the strength of the steering tube too much.

If that's the case, what's the diff between that and:

1) Really high riser bars - like 3". Isn't the leverage still there down where
the steering tube goes into the headset?

2) Steering tube extensions that clamp on to the existing protrusion - same
observation about the leverage still being there.


My agenda is that my riser bars are pretty high, and I've already trimmed my
steering tube so it's max stack is about 1.25". If I replace those risers and
want to keep the same bar height, I'll be faced with a choice between getting
risers that are just as extreme and getting, say, 1" risers and elevating the
stem attachment point (the stem's height is already max..).

Any thoughts besides getting a custom frame?
-----------------------
PeteCresswell

(Pete Cresswell) wrote:

Seems to me like I read somewhere that the max height of a spacer stack was
something like 1.25 or 1.5 inches - anything in excess of that was challenging
the strength of the steering tube too much.

That sounds like either a limit for carbon or aluminum steerers
(possibly less for carbon) or manufacturer's ass-covering.
A steel steer tube is quite strong. It is stronger and stiffer
than other devices used to get several inches of rise, such as
the swanlike 22.2mm diameter aluminum Nitto Technomic stem, or the
aluminum and steel quill riser stems that most early MTBs came with.

I'm pretty sure there are folding bikes out there with very long
steerer extensions. Of course, they aren't intended for big
dirt-jumping, but I think you aren't planning on that.


If that's the case, what's the diff between that and:

1) Really high riser bars - like 3". Isn't the leverage still there down where
the steering tube goes into the headset?

2) Steering tube extensions that clamp on to the existing protrusion - same
observation about the leverage still being there.

RE/
Is the steerer tube Al or Fe? Is it 1'"or 11/8"?
If it is 1 1/8" steel, the sky's the limit.

1", Al. Marzocci X-Fly 100 fork.....
-----------------------
PeteCresswell