How much thread on the axle?

I've just been doing some work on my rear wheel and noticed how little
of the axle is being used to support the frame. It looks to me that the
weight of the bike may even be being supported by the quick release
screw. Anyway, I'm hoping someone can let me know if this is normal or a
recipe for disaster. Seeing I'm only just recovering from a headstem
stuff up, I think I might get banned from cycling if another mechanical
failure occurs. I dropped some pics onto the following url to show what
I mean.

http://members.optusnet.com.au/~dbue...stuff/axle.htm

Dave B.

"DaveB" wrote in message
...
I've just been doing some work on my rear wheel and noticed how little
of the axle is being used to support the frame. It looks to me that the
weight of the bike may even be being supported by the quick release
screw. Anyway, I'm hoping someone can let me know if this is normal or a
recipe for disaster. Seeing I'm only just recovering from a headstem
stuff up, I think I might get banned from cycling if another mechanical
failure occurs. I dropped some pics onto the following url to show what
I mean.

http://members.optusnet.com.au/~dbue...stuff/axle.htm

After checking your pics I would suggest that you need to recentre your axle
in the cones/nuts. It is too far over to the LH side.

Back off the LH nut and cone several turns, then tighten the RH cone to
readjust the bearing and lock in place. This should give you about 4mm of
axle protruding on each side. At present you have about 2mm on the right and
6mm on the left. With the axle centred you'll have no problems.

Cheers
Peter

Peter Signorini wrote:
"DaveB" wrote in message
...

I've just been doing some work on my rear wheel and noticed how little
of the axle is being used to support the frame. It looks to me that the
weight of the bike may even be being supported by the quick release
screw. Anyway, I'm hoping someone can let me know if this is normal or a
recipe for disaster. Seeing I'm only just recovering from a headstem
stuff up, I think I might get banned from cycling if another mechanical
failure occurs. I dropped some pics onto the following url to show what
I mean.

http://members.optusnet.com.au/~dbue...stuff/axle.htm


After checking your pics I would suggest that you need to recentre your axle
in the cones/nuts. It is too far over to the LH side.

Back off the LH nut and cone several turns, then tighten the RH cone to
readjust the bearing and lock in place. This should give you about 4mm of
axle protruding on each side. At present you have about 2mm on the right and
6mm on the left. With the axle centred you'll have no problems.

Cheers
Peter



Even then though I'll still only have about 4mm at either end, so I'm
wondering if that is normal. Is that what the frame is supported by? My
MTB (which is certainly getting on in years) doesn't have quick release
so obviously the axle goes well out either side of teh frame for the
lock nuts, and when I look at the MTB compared to the road bike
something just doesn't look right.

Dave B

DaveB:

Even then though I'll still only have about 4mm at either end, so I'm
wondering if that is normal. Is that what the frame is supported by? My
MTB (which is certainly getting on in years) doesn't have quick release
so obviously the axle goes well out either side of teh frame for the
lock nuts, and when I look at the MTB compared to the road bike
something just doesn't look right.

4-5mm of thread contact with dropouts is typical for both MTBs and road
bikes. There hasn't been any significant problems because of this. The
only concern is if you have ultra-thick dropouts and your skewer rod
then becomes too short; I think this is a non-issue though.

"DaveB" wrote in message
...
SNIP
then though I'll still only have about 4mm at either end, so I'm
wondering if that is normal. Is that what the frame is supported by? My
MTB (which is certainly getting on in years) doesn't have quick release
so obviously the axle goes well out either side of teh frame for the
lock nuts, and when I look at the MTB compared to the road bike
something just doesn't look right.

Dave B


It's the friction which keeps your axle in place, by pressing the lug
against the retaining bolt. You would ruin the thread if you would put all
the weight directly on the axle.
Just look at the lug of a road bike, the axle is often not positioned at the
back of the lug opening, but somewhere in the middle and has to be kept
there by pressing the nut against the lug.
Also when you have an axle which protudes on both sides and is attached with
locking nuts, the forces are transmitted metal to metal, via the friction.


Joop

Joop:


"DaveB" wrote in message
...
SNIP
then though I'll still only have about 4mm at either end, so I'm
wondering if that is normal. Is that what the frame is supported by? My
MTB (which is certainly getting on in years) doesn't have quick release
so obviously the axle goes well out either side of teh frame for the
lock nuts, and when I look at the MTB compared to the road bike
something just doesn't look right.

Dave B


It's the friction which keeps your axle in place, by pressing the lug
against the retaining bolt. You would ruin the thread if you would put all
the weight directly on the axle.

No, the rider's weight is taken up by the axle threads in contact with
the dropouts. Look at your dropouts and you'll see scoring where the
axle threads make contact.

Just look at the lug of a road bike,

Lug?

the axle is often not positioned at the
back of the lug opening, but somewhere in the middle and has to be kept
there by pressing the nut against the lug.
Also when you have an axle which protudes on both sides and is attached with
locking nuts, the forces are transmitted metal to metal, via the friction.

The axle takes up the weight of the rider, not the nuts nor QR knobs.
These mainly keep the hub from going out of the dropouts.

"Jose Rizal" wrote in message
ink.net...
Joop:


SNIP
No, the rider's weight is taken up by the axle threads in contact with
the dropouts. Look at your dropouts and you'll see scoring where the
axle threads make contact.


The friction forces are very strong. If I position the front wheel a bit
down from the stops and I put my full weight on it, the axle does not slip.
So it can take 90+ kg on one wheel with friction only. Also I often have one
side of the front axle to the stop and the other is a bit off for propoer
positioning: and it stays there (no shifting).

The scoring marks can be there as there always a slight movement possible
but I think they are mainly from when the wheel is put in. If it would only
rest on the threads, they will be crushed with all shock forces from the
bumps on the road.
As a kid I often failed to tigthen the bolts properly and I often had an
axle where I could not get the bolts off: the threads were completely
squashed.



the axle is often not positioned at the
back of the lug opening, but somewhere in the middle and has to be kept
there by pressing the nut against the lug.
Also when you have an axle which protudes on both sides and is attached
with
locking nuts, the forces are transmitted metal to metal, via the
friction.

The axle takes up the weight of the rider, not the nuts nor QR knobs.
These mainly keep the hub from going out of the dropouts.


I think it is the other way around: firstly the forces are distributed via
friction, the axle-dropout contact is a second line of defence.


Joop

Replacement rear axles are typically 11mm longer than the OLN dimension
(eg 141mm for 130mm OLN, 146mm for 135mm OLN), which means 5.5mm at each
end. I've added a 2mm spacer each side to use a 130mm hub in a 135mm
frame, bringing it down to 3.5mm each side and had no problems, so I
would say anything over 3mm or so is fine.

Nick

DaveB wrote:

Even then though I'll still only have about 4mm at either end, so I'm
wondering if that is normal. Is that what the frame is supported by? My
MTB (which is certainly getting on in years) doesn't have quick release
so obviously the axle goes well out either side of teh frame for the
lock nuts, and when I look at the MTB compared to the road bike
something just doesn't look right.

Dave B

On Wed, 31 Mar 2004 02:01:53 GMT, Jose Rizal wrote:

No, the rider's weight is taken up by the axle threads in contact with
the dropouts. Look at your dropouts and you'll see scoring where the
axle threads make contact.

That may be the norm but it isn't necessarily so I had a bike which
had a slight mishap and if the axle was put in the correct place in
the dropouts the wheel didn't run true. It had to be out of position
on one side but it ran like this for years without the axle touching
the dropouts on one side and relying on the friction of the QR dobbie
to hold it in place - The QR was no tighter than normal