Spoke tension

[johnnyb47]

Hi.
I was just wondering if any of you knowledgeable gurus here may know a thing or two about spoke tensions. Tonight whilst giving my bike a clean I noticed one of the rear spokes was really loose. I've let the tyre down and tensioned it up again being careful not to over tighten it and kept a keen eye in the wheel staying nice and true. I did notice though that the spokes on the rear cassette side seem to hold a lot more tension than the opposite side. Is this perfectly normal for a rear wheel or should I think about taking it down to my local bike store to check it over. Tapping a screw driver on each spoke side gives off a near enough ring sound but I can imagine even this test is not an accurate way to judge the spokes are properly tensioned.
Many thanks.
Johnny

 

[raleighnut]

Drive side spokes have to be tighter on a dished wheel.

 

[johnnyb47]

Thanks Raleighnut. I was kind suspecting this was correct but not 100% sure if it was right through. This is twice now though that I've had to tighten up some loose spokes on my bike in the last 1000 miles. Over the years of bike ownership I've never had to ever tighten any spokes so it's just made me a little suspicious as to whether this present rear wheel needs checking over.

 

[GlenBen]

Personally, I woyld just take it in for peace of mind, my LBS only charges £10 to do a wheel.

 

[smutchin]

Tapping a screw driver on each spoke side gives off a near enough ring sound but I can imagine even this test is not an accurate way to judge the spokes are properly tensioned.

Well, it works for me.

Not that I am the most experienced wheel builder, but plucking the spokes and comparing the tone is the method I learned for checking they are evenly tensioned.

Or you could spend a lot of money on a tensiometer.

 

[Yellow Saddle]

Thanks Raleighnut. I was kind suspecting this was correct but not 100% sure if it was right through. This is twice now though that I've had to tighten up some loose spokes on my bike in the last 1000 miles. Over the years of bike ownership I've never had to ever tighten any spokes so it's just made me a little suspicious as to whether this present rear wheel needs checking over.

If your spokes regularly come loose then you need to have all of then tensioned a bit more. Nipples remain stuck through ramp friction in the threads - If there is not enough tension in the spoke, there isn't enough friction and the nipples unscrew. This is a job for a skilled person.
However, your method of checking for loose spokes by listening to the tone is good. That's how we all do in in the industry.
You do however have to note that not all spokes on a side will have exactly the same tension. This is because of unevenness in the rim itself. Small imperfections, seams and valve holes all affect a rim's strength in a particular position and therefore spokes can't all have exactly the same tension when the wheel is straight.

 

[KnackeredBike]

Adjusting spokes well takes either patience or practice of which I have neither. It's also very cheap to have done professionally so excepting emergency "get me to work" adjustments I'm happy to pay a few quid for peace of mind that the wheel won't come out of true miles from home.

 

[User6179]

Thanks Raleighnut. I was kind suspecting this was correct but not 100% sure if it was right through. This is twice now though that I've had to tighten up some loose spokes on my bike in the last 1000 miles. Over the years of bike ownership I've never had to ever tighten any spokes so it's just made me a little suspicious as to whether this present rear wheel needs checking over.

My non drive side spokes have loosened on all my back wheels in recent years except a Fulcrum 5 which has an oversized flange on one side of the hub making the spoke tension more equal .

The only way I can solve the issue is to over tighten the non drive spokes which pulls the wheel a bit closer to the chainstay on that side meaning the wheel is not centred or put some thread lock on the spoke threads which is very time consuming .

 

[Ian H]

I tend to build my wheels pretty tight. Also, I use 3-in-1 oil on the threads. It's a cheap oil which turns to gum as it dries, so acts a little bit like a gentle thread-lock.

The only way I can solve the issue is to over tighten the non drive spokes which pulls the wheel a bit closer to the chainstay on that side meaning the wheel is not centred or put some thread lock on the spoke threads which is very time consuming .

Tighten both sides to maintain the centring.

 

[User6179]

I tend to build my wheels pretty tight. Also, I use 3-in-1 oil on the threads. It's a cheap oil which turns to gum as it dries, so acts a little bit like a gentle thread-lock.


Tighten both sides to maintain the centring.

I have tightened the drive side to the absolute max before doing the NDS , I still need to pull the wheel over to the NDS but not by as much but I have found over tightening the drive side gives you worst problems , the last wheel I did this with was 36 spokes and when I snapped one of the DS spokes the wheel went so far out of true because it was over tensioned it jammed the tyre on the chainstay , I have managed to limp home with 20 spoked wheels when one spoke has snapped so was not expecting a 36 spoke wheel to go so far out but it did .

I just wonder if to accommodate 11 speed cassettes has the distance between the spoke flanges changed making the spoke tension more unequal or was it just my 100kg plus lardy ass loosening spokes .( now 90kg)

 

[Yellow Saddle]

I have tightened the drive side to the absolute max before doing the NDS , I still need to pull the wheel over to the NDS but not by as much but I have found over tightening the drive side gives you worst problems , the last wheel I did this with was 36 spokes and when I snapped one of the DS spokes the wheel went so far out of true because it was over tensioned it jammed the tyre on the chainstay , I have managed to limp home with 20 spoked wheels when one spoke has snapped so was not expecting a 36 spoke wheel to go so far out but it did .

I just wonder if to accommodate 11 speed cassettes has the distance between the spoke flanges changed making the spoke tension more unequal or was it just my 100kg plus lardy ass loosening spokes .( now 90kg)

Right and left may make the conversation less cumbersome.

I don't know what you mean by max. However, no spoke should ever be tightened so much that the nipples cannot turn anymore. That's going overboard.
A spoke cannot break from spoke tension alone. The rim will give first or the nipple will gall first. Spokes have plenty of tensile strength. However, a spoke can break when you apply a combination of tension and torsion. Then it will break at relatively low tensions - before yield. In other words, it is easy to break a spoke if you allowed it to wind up when tensioning.
There is something seriously wrong with a 36 spoke that goes so much out of true when one spoke breaks that it jams against the chainstay. You are doing something wrong.
As for the last question, it has already been explained why nipples unscrew.

 

[User6179]

Right and left may make the conversation less cumbersome.

I don't know what you mean by max. However, no spoke should ever be tightened so much that the nipples cannot turn anymore. That's going overboard.
A spoke cannot break from spoke tension alone. The rim will give first or the nipple will gall first. Spokes have plenty of tensile strength. However, a spoke can break when you apply a combination of tension and torsion. Then it will break at relatively low tensions - before yield. In other words, it is easy to break a spoke if you allowed it to wind up when tensioning.
There is something seriously wrong with a 36 spoke that goes so much out of true when one spoke breaks that it jams against the chainstay. You are doing something wrong.
As for the last question, it has already been explained why nipples unscrew.

Max = yes about as tight as you can turn then a quarter turn back .

I tightened the 36 spoke wheel against my better judgement to the max on the right DS as the spokes were needing tightening about every 10 miles on the left NDS even when pulling the wheel over to that side by over tensioning the left DS , I ended up using some thread lock then the spoke snapped .

Anyway I gave up on the wheel as after the spoke snapped it turned into an egg and the new spoke I put on failed to pull it true , I could not be bothered loosening all the spokes and starting again on a wheel that was impossible to keep true .

 

[smutchin]

I could not be bothered loosening all the spokes and starting again on a wheel that was impossible to keep true

Thing is, that's probably the only way you're going to rectify your problem wheel. It's only impossible to keep true because of the way it's been built in the first place.

 

[johnnyb47]

Many thanks to all for replying. From what i understand from your posts my wheel is pretty much somewhere near where it should be ,so I will continue to get the miles in and keep an eye on it.