Author Topic: Spoke torque question  (Read 15567 times)

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geoffbaker

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on: March 10, 2008, 03:23:00 pm
I had to replace a spoke yesterday. I've done it plenty of times - on my bicycles!

It was pretty easy (except getting the tire off with the supplied RE tire irons... they bend like taffy...)

It's the one time I regret having a military model... more stuff to take off before you can get the back wheel out!

My question is, is there a torque setting for spokes? I came across a spoke torque wrench online that claimed there were specific settings for different bikes... it would be nice if you could set the spokes at a specific torque quickly and easily. It would help keep the wheel in basic true, although it wouldn't be enough for accurate tuning...

here's the tool... http://www.cyclebuy.com/shopping/fasstco/spoke_wrench.htm

Advice welcomed!


Vince

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Reply #1 on: March 10, 2008, 03:43:08 pm
     This tool may help, but being from the old school I do it by ear. Generally you want the spoke to have a nice clear tone to it when you tap it with your wrench. The mistake people make is to tighten one spoke at a time. Go around the wheel 3 or more times, tightening the loose ones 1/4 turn at a time. You can rig up a pencil as a pointer to check true. When you find a spot out of true, start tightening from 6 spokes away from both sides of the problem area. DON'T crank on the one spoke that seems  to be the problem. If it's not going well then loosen a bunch of spokes and start over. TAKE YOUR TIME!!!


geoffbaker

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Reply #2 on: March 10, 2008, 04:20:50 pm
Vince,

I spent a few years working in a bike shop thirty years ago, so I got my time in truing wheels :) Probably need a refresher course now, though.

I think its important to state that this tool doesn't replace good spoke tuning and wheel truing... my thought is merely that it might be a quick way to keep a wheel from running out of true too quickly, and a good part of a maintenance program ...

But is there a "standard" torque setting for RE spokes? Does the recommendation of 48 inchpounds sound right?


Vince

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Reply #3 on: March 10, 2008, 04:53:25 pm
     I have to say I don't know. However, a 6mm bolt (1/4") generally takes 96 inch pounds. So 48 inch pounds sounds fine. I don't see how you could go wrong with that.


LotusSevenMan

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Reply #4 on: March 12, 2008, 08:56:39 am
Had an ex wife who was like this problem whenever she was on the 'phone............

Just spoke and talk (ed)!!!!

 ::)
« Last Edit: March 12, 2008, 06:16:33 pm by LotusSevenMan »
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Al

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Reply #5 on: March 20, 2008, 11:59:29 am
 When truing a wheel, it is important that spoke tension be as uniform as possible. All this talk about  the torque  of a replacement spoke makes me shudder.


geoffbaker

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Reply #6 on: March 20, 2008, 02:40:07 pm
A spoke torque wrench is a tool that guarantees uniform spoke tension, by design ... so it should be a good thing, right? :)
Speaking as someone who spent years truing wheels (lacing, dishing, truing... I worked in a bicycle shop where wheel truing is a weekly, not annual job...) I welcome the idea of any tool that can simplify the job... and as I said before, I wouldn't use it to replace hand and eye skills... but it sounds like a magificent tool to get your wheel quickly into shape, before accurate tuning...

Which, I suppose is why race mechanics and professionals were the first to adopt spoke torque wrenches...
« Last Edit: March 20, 2008, 04:55:02 pm by geoffbaker »


geoffbaker

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Reply #7 on: March 31, 2008, 05:22:29 pm
I did purchase a spoke torque wrench and it arrived last week. Over the weekend, I had to change my front tire anyway (slow leak) so I used the wrench while I was at it, on both wheels.

I have to say, I'm quite impressed. I was also surprised by how many spokes needed tightening (I had thought they were in pretty good shape)... but I was rewarded by a wheel where the spokes "rang" perfectly.


birdmove

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Reply #8 on: March 31, 2008, 09:09:31 pm
  Does this torque wrench come with the toque already set, or is it adjustable?
    jon
Jon in Keaau, Hawaii


geoffbaker

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Reply #9 on: March 31, 2008, 09:53:24 pm
The one I got is adjustable.. an excel. (About half the price of the fasst wrench)

It's currently set to 48 inch pounds. Did a great job!

BTW, spoke nipples on the RE are 6.4mm wide.


LJRead

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Reply #10 on: April 01, 2008, 03:58:06 am
The question is, when all the spokes are at the same torque (48 inch lbs for example) is the wheel true?


SRL790

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Reply #11 on: April 01, 2008, 04:28:01 am
My experience, when re-torquing spokes, is that if there is any dirt and/or corrosion in the threads then the torque applied is not going to be proportional to the tension.   Some of them get quite stiff with age.  A drop of penetrating oil first might help. 

When assembling a new wheel though, especially for those of us that don't do it that often, a torque wrench would be handy to re-calibrate our fingers and ears.

The answer to your question LJ is no.  It is possible to have all the spokes at the same tension and end up with something that looks like it belongs in a circus act (Ask me how I know)!
Andy Wiltshire
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LJRead

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Reply #12 on: April 01, 2008, 05:11:30 am
Good clear answer, Andy.  Taking this torque wrench question one step further, there is beginning to be a question in my mind as to whether all these torque values and a torque wrench are that necessary or even to be desired.  For example, one of the spark plug manufacturers apparently recommends against torquing spark plug or, especially, torquing them when a preparation such as anti-seize has been used (they advised against using it).  With anti-seize, it becomes to easy to over torque because of the lack of friction.  I was raised with the idea of torquing head bolts, but, when young, torque values didn't seem to have such a prominence.  Head bolts yes, but I don't recall worrying about others.  In early years I would tighten the hell out of bolts and break off a percentage of them.  With that experience, I learned to snug things down till they seemed good enough.

There is a website put together by an Indian mechanic who advises not to use a torque wrench, but rather to learn to feel when the threads start pulling. 

Getting back to the spoke torque wrench, it seems that it might be very useful for initial setting up, but a final spin on a wheel stand would be appropriate. 


geoffbaker

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Reply #13 on: April 01, 2008, 01:55:51 pm
Getting back to the spoke torque wrench, it seems that it might be very useful for initial setting up, but a final spin on a wheel stand would be appropriate. 

Which is what I've said, all along...

A torque wrench is a quick and easy way of applying more or less uniform torque values to any given set of objects - head bolts, spokes, whatever.

I don't consider a torque wrench to be the final step, it's merely the first step - and a very quick way to get to the next step...

which is to check the wheel for true, vertically and horizontally.

Truing a wheel is a very easy process and can be done on the motorcycle, in a pinch, but is also easy to do if you have a vice and a worktable. I use a bicycle stand.

I would also agree that individual spokes will react differently to the same torque value, based on age, rust, dirt, etc.

The trick is to get the wheel up into the "zone" where everything is more or less similar, and then tighten or loosen, where necessary, to bring the wheel into true.

The torque wrench is - in my opinion, based on my first use of this tool - an excellent shortcut to get you to the "zone".

I wouldn't consider myself an expert on motorcycle wheels. But there was a time where I did this for a living, on bicycle wheels - which are far more finicky, and need to be darn close to perfectly adjusted, on race bikes - or you will break spokes like a madman!


LJRead

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Reply #14 on: April 01, 2008, 05:21:11 pm
A spoke torque wrench is a tool that guarantees uniform spoke tension, by design ... so it should be a good thing, right? :)
... and as I said before, I wouldn't use it to replace hand and eye skills... but it sounds like a magificent tool to get your wheel quickly into shape, before accurate tuning...

Getting back to the spoke torque wrench, it seems that it might be very useful for initial setting up, but a final spin on a wheel stand would be appropriate. 

Yeah, I guess we did say the same thing.  I can see having a spoke torque wrench for initial spoking of a wheel, but for minor tuning up of already spoked wheels,  maybe not so necessary


geoffbaker

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Reply #15 on: April 01, 2008, 05:43:45 pm
Quote
Yeah, I guess we did say the same thing.  I can see having a spoke torque wrench for initial spoking of a wheel, but for minor tuning up of already spoked wheels,  maybe not so necessary

Actually, the torque wrench is even better for correcting a very common error... OVER tensioning of spokes.

It's very easy to try to fix a wheel and either overtighten a whole range of spokes or overtighten the WRONG spokes, which just makes the problem worse. Then you overtighten the opposite spokes, again... creating a serious tension area in the wheel, even if it remains roughly in true.

A torque wrench is a built in limiting device which prevents this...

Better, when facing a difficult wheel, to lower off the tension all round, and then bring it back up uniformly, and then isolate, and fix, any wobbles...

As I said earlier, this is my first trial of a torque wrench designed for spokes. I'll keep using it and checking, and report back if I find any negatives...

So far, so good, though.

LJ: I missed this earlier...

The question is, when all the spokes are at the same torque (48 inch lbs for example) is the wheel true?

The answer of course, is NO! I had to tighten some and loosen others to bring it into true. There was one significant wobble which needed immediate correction, and a slight swing over about half the arc of the wheel, which was not as bad. I fixed both. The question is did it save time and improve overall accuracy? I'd say yes. After using the spoke torque wrench to run around the wheel three times, tightening slowly and evenly, I trued the wheel completely, which took perhaps another five minutes. It's now within 1/16 of an inch of true throughout the wheel, which I think is pretty good for a motorcycle wheel. That's horizontally; vertical looked perfect throughout.

What with the truing, checking the brakes, changing the tires and tubes, I'm getting pretty good at taking these wheels off!
« Last Edit: April 01, 2008, 07:54:25 pm by geoffbaker »


LJRead

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Reply #16 on: April 01, 2008, 08:03:55 pm

Very nice information Goeff!  Very pleased to have a thorough discussion of such an important item.  The clinching argument of the danger of over tensioning is something I didn't even consider.

If you have a link to your torque wrench seller, this would be appreciated too, or was it the one you already gave?- I will be having five wheels to keep in tune, so you've convinced me of its need.

Again thanks,

Larry


geoffbaker

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Reply #17 on: April 01, 2008, 08:45:25 pm
I got mine off ebay. :)

Just type in "spoke torque wrench" and see what happens!

Here's an excel link
http://www.motorcycle-superstore.com/3/13/133/4663/ITEM/Excel-Spoke-Torque-Wrench.aspx

Don't know about a website for excel.

American made FASST wrenches:
http://www.fasst.info/products/adjwrench.shtml

Twice the cost!

One version of fasst is pretensioned to 48 inch pounds. The other is adjustable, like the excel.

I preferred the idea of an adjustable, that way I can start lower (say at 40), check the true, and then bring it up slowly. Again, less chance of overtightening.


SRL790

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Reply #18 on: April 02, 2008, 04:52:26 am
One point that I would like to bring up about replacing spokes is that the nipples, and the holes in the rim, come in different sizes.  Make sure that the spoke nipples are the correct size for holes in the rim.

I spoked a wheel one time and the nipples started pulling through the holes because they were too small.  Expensive lesson learned!
Andy Wiltshire
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70 Bonneville, 71 Bonneville, 71 BSA B25T, 74 Jensen Healey
74 Honda XR75, 81 Yamaha MX80, 82 Suzuki GS1100G


dogbone

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Reply #19 on: April 02, 2008, 02:34:03 pm
 :D  I had mine tuned to c sharp
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geoffbaker

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Reply #20 on: April 02, 2008, 03:58:00 pm
Thanks for the tip SRL, I'll keep that in mind when ordering new spokes (hopefully, not for a long time!). My bike came with four spare spokes (does this mean the PO was breaking them, I wonder?)

Dogbone, c sharp is  better than B Flat, right? :P