Just how long should a spoke be.

[mike killay]

Just how long should a spoke be?
What I mean is should the spoke need to be bent to fit it into the ferrule, or should it be just long enough to reach the wheel rim?

 

[MarcusT]

The nipple should be retracted when installing a new spoke, so no bending involved. If you do not know the length you need , I just measure it so the spoke goes about half way through the nipple when just tight. Too long or too short will give you problems.
Try :

How to Measure Spokes

How to measure spokes - Ideally done with a spoke ruler but can also be measured from the inside of the J-Bend to the end of the thread on a spoke.

www.customcutspokes.co.uk

 

[Sturmey]

....... should it be just long enough to reach the wheel rim?

An extra 3-4mm approx is preferable, (2mm rim thickness + 2mm more to go into nipple head. The spoke may stretch about 1mm when tightened).

Measurements for Bicycle Spoke-Length Calculations

This article describes how to measure a bicycle rim and hub as input for a spoke length calculator application when building a bicycle wheel.

www.sheldonbrown.com

 

[sjpt]

An extra 3-4mm approx is preferable, (2mm rim thickness + 2mm more to go into nipple head. The spoke may stretch about 1mm when tightened).

Measurements for Bicycle Spoke-Length Calculations

This article describes how to measure a bicycle rim and hub as input for a spoke length calculator application when building a bicycle wheel.

www.sheldonbrown.com

but not too much extra, or the spoke can poke through the rim tape and give you a puncture. (I guess it's an advantage on tubeless that that doesn't apply.)

 

[mike killay]

An extra 3-4mm approx is preferable, (2mm rim thickness + 2mm more to go into nipple head. The spoke may stretch about 1mm when tightened).

Measurements for Bicycle Spoke-Length Calculations

This article describes how to measure a bicycle rim and hub as input for a spoke length calculator application when building a bicycle wheel.

www.sheldonbrown.com

So you do bend it to install it?

 

[Sturmey]

So you do bend it to install it?

When a new wheel is being built, the spokes are not bent. But, when you are replacing an individual spoke, you can bend as much as necessary. However, dont bend at the ends (thread or 'j' bend). The spoke straightens remarkably well when put under tension.
Its often possible to (quickly) replace a spoke without removing the wheel or tyre.

 

[Andy-Mat]

When a new wheel is being built, the spokes are not bent. But, when you are replacing an individual spoke, you can bend as much as necessary. However, dont bend at the ends (thread or 'j' bend). The spoke straightens remarkably well when put under tension.
Its often possible to (quickly) replace a spoke without removing the wheel or tyre.

Interesting! Without removing the tyre....
I have never, in a long line of bikes going back over 60 years, had a spoke break or need placing. Just lucky I guess. Gently tightened a few, thats all....
Its a job that I would like to try my hand at sometime...
Andy

 

[BazP]

Interesting! Without removing the tyre....
I have never, in a long line of bikes going back over 60 years, had a spoke break or need placing. Just lucky I guess. Gently tightened a few, thats all....
Its a job that I would like to try my hand at sometime...
Andy

Earlier this year my partner had three spokes break, at separate times whilst out on rides. The wheel has now been replaced. However on all three occasions I managed to replace the spokes without removing the tyre.
Being on the nearside rear wheel I had to remove the rotor to insert the new spoke. This could have been worse had it been on the cassette side but the nipples, still with a piece of spoke in them, had not disappeared due to the rim tape. you can hold the nipple with pliers whilst screwing the new spoke in.
As mentioned above, I did have to bend the spokes to start the thread but they easily straightened.
I always carry a spare spoke with me but usually a broken one can be wrapped around its neighbour until you get home.

 

[mike killay]

Thanks for replies, just found that I have been trying to fit 133 mm spokes to a wheel that only needs 126 mm spokes!
As for fitting spokes without removing the tyre, I would suppose that only applies to shallow rims, not twin wall ones.
However, I was successful at fitting the spoke by not removing the wheel, just taking off one side of the tyre, pushing the side still fitted across the width of the rim which allowed me to hook the rim tape out of the way and get access to the nipple.

 

[Andy-Mat]

Earlier this year my partner had three spokes break, at separate times whilst out on rides. The wheel has now been replaced. However on all three occasions I managed to replace the spokes without removing the tyre.
Being on the nearside rear wheel I had to remove the rotor to insert the new spoke. This could have been worse had it been on the cassette side but the nipples, still with a piece of spoke in them, had not disappeared due to the rim tape. you can hold the nipple with pliers whilst screwing the new spoke in.
As mentioned above, I did have to bend the spokes to start the thread but they easily straightened.
I always carry a spare spoke with me but usually a broken one can be wrapped around its neighbour until you get home.

Great post, thanks.
Andy

 

[Nealh]

I have replaced spokes on a twin wall rim with wheel in situ, the spoke does though need a little flexing to thread the crossing and into the nipple.

 

[Sturmey]

Interesting! Without removing the tyre....

On e bikes, the spokes often break at the 'j' bend on rear hub motors, so it is often easy to replace the spoke, especially if the bike has v brakes (no disk ) and hub is often bigger than freewheel so there is nothing in the way.
It is not even necessary (with double walled rims) to deflate the tyre in this case. You also have to be careful not to let the nipple push through/fall into the cavity on the deeper sectioned double walled rims.

 

[mike killay]

On e bikes, the spokes often break at the 'j' bend on rear hub motors, so it is often easy to replace the spoke, especially if the bike has v brakes (no disk ) and hub is often bigger than freewheel so there is nothing in the way.
It is not even necessary (with double walled rims) to deflate the tyre in this case. You also have to be careful not to let the nipple push through/fall into the cavity on the deeper sectioned double walled rims.

Most authorities suggest that the spoke engage the whole thread of the nipple and end up just sub-flush with the screwdriver slot. This suggests that the spoke is actually poking slightly into the wheel when fitted, so my original question as to should you bend the spoke to shorten it still stands, otherwise it will not go into the nipple aperture in the wheel

 

[BazP]

Most authorities suggest that the spoke engage the whole thread of the nipple and end up just sub-flush with the screwdriver slot. This suggests that the spoke is actually poking slightly into the wheel when fitted, so my original question as to should you bend the spoke to shorten it still stands, otherwise it will not go into the nipple aperture in the wheel

Don’t really understand your question re bending the spoke.
If the tyre is off and the nipple is out then there is no need to bend the spoke. Measure it flush with the rim and fit the nipple.
If the tyre is on and the nipple is still in place, captivated by the rim tape, then you will have to bend the spoke slightly to enter the nipple thread but it will straighten as soon as you start to screw on the nipple.
From an engineering perspective it is only the depth of thread that is equal to the thread diameter that takes the force i.e. For a 2mm male thread the first 2mm of the internal thread will take the load. Making it longer may help with not vibrating loose and may add some mental comfort. I usually double this and can relax.

 

[Nealh]

Lacing the spoke it will have to, to a degree be flexed and also in to the nipple if doen with the tyre in-situ.
The actual question of How long a spoke should be is down to the rim ERD and calcs using a spoke calculator.

 

[Sturmey]

.....
From an engineering perspective it is only the depth of thread that is equal to the thread diameter that takes the force i.e. For a 2mm male thread the first 2mm of the internal thread will take the load. Making it longer may help with not vibrating loose and may add some mental comfort. I usually double this and can relax.

Nipples (especially aluminium) can break.

 

[mike killay]

Nipples (especially aluminium) can break.

Precisely, according to that, the spoke should be longer than the distance from the hub to the rim, so it will have to be bent to be fitted

 

[mike killay]

Don’t really understand your question re bending the spoke.
If the tyre is off and the nipple is out then there is no need to bend the spoke. Measure it flush with the rim and fit the nipple.
If the tyre is on and the nipple is still in place, captivated by the rim tape, then you will have to bend the spoke slightly to enter the nipple thread but it will straighten as soon as you start to screw on the nipple.
From an engineering perspective it is only the depth of thread that is equal to the thread diameter that takes the force i.e. For a 2mm male thread the first 2mm of the internal thread will take the load. Making it longer may help with not vibrating loose and may add some mental comfort. I usually double this and can relax.

Seems you are wrong, this leads to broken nipple heads.