Author Topic: How true is true?  (Read 3292 times)

Offline JustcallmeMrT

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How true is true?
« on: April 14, 2015, 08:26:42 PM »
According to my dial gauge I'm within 0.2mm of true left to right and up and down.  Good enough?  What is an acceptable tolerance?

Also, how tight should spokes be?

Offline JamesH

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Re: How true is true?
« Reply #1 on: April 14, 2015, 08:27:46 PM »
That's probably better than factory tolerances so I think you'll be fine...

Offline csd4t

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Re: How true is true?
« Reply #2 on: April 14, 2015, 08:31:48 PM »

Well within tolerance, MOT is +- 1.5mm if my memory serves me correctly.
There is no F in cod

Offline Trigger

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Re: How true is true?
« Reply #3 on: April 14, 2015, 08:36:25 PM »
That is true enough. Spokes is down to sound, a bit like tuning a piano. You need a good tune  ;D ;D

Offline JustcallmeMrT

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Re: How true is true?
« Reply #4 on: April 14, 2015, 09:37:16 PM »
I need a tuning fork!

Offline Trigger

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Re: How true is true?
« Reply #5 on: April 14, 2015, 09:54:35 PM »
No, just tap them with your spoke key ;)

Offline JustcallmeMrT

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Re: How true is true?
« Reply #6 on: April 14, 2015, 09:56:46 PM »
Well, they all sound about the same to me now, just don't know when they're tight enough as a whole.

Offline Trigger

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Re: How true is true?
« Reply #7 on: April 14, 2015, 09:59:51 PM »
When they go ping and not a dull sound  ;)

Offline csd4t

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Re: How true is true?
« Reply #8 on: April 14, 2015, 10:38:21 PM »
They all need to go "ting" and none of them go "tong" ;)
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Offline Lobo

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Re: How true is true?
« Reply #9 on: April 15, 2015, 11:37:58 AM »
Shamelessly copied from some thread somewhere. There'll be those that jump up & down yelling, "but it's off the internet... it can't be trusted".... but hey ho, short of talking directly with god it'll hopefully do.
I seem to remember reading somewhere (!) 01mm was fine for speeds up to 80mph.
Oh, and "wow" to your 0.2mm.... my DSS DID rims welds were more than this!
Simon.

............Do this enough times until you are happy with your work, then gradually go around tightening the spokes. They don’t need to be death tight. There are lots of them and they all need to share the work equally. As you rotate the wheel strike the spokes lightly with you spanner. They should start to give a nice crisp ‘ding’ not a dull ‘thud’ or an over tightened ‘ping’. Get a soft-faced mallet and go around the wheel and give every spoke a light wack. This will settle the spokes, one might have been tightened up with a slight bow in it. A gentle knock with the hammer will spring it into line and it will now probably have a dull thud to it when struck with your tuning spanner. By now the wheel should be pretty close to being right. Keep checking offset, checking radial runout, and checking axil runout

Time for a cuppa or a beer. Come back later after the nerves have settled, run around it with the tuning spanner, ding, ding, dong, ding and give it that final touch……….. Should be pretty right after all that.


Finishing

If your keen enough, you can now check your work with a dial gauge. Most motorcycle manuals specify a maximum runout figure of 2mm or .080 in. You should easily get a new rim well under 1mm or .040 in. An old re-laced rim would still come somewhere near 1 mm or .040 in unless it had a bit of a woof in it. Put the rim band on, fit your tyre and make sure the bead sits down properly and you have correct air pressure. Put the fully assembled wheel back up in your jig and give it a slow spin and see how it goes for balance. Static balancing a wheel is another easy job that makes a lot of difference to the performance of the bike. You can buy proper wheel weights that either stick onto the rim or clamp around the spoke. You can cut strips of lead and wrap them around the spokes or cut strips of lead and stick them to the rim with silicon.

Spin the wheel slowly and wait for it to come to rest. Mark the top of the tyre with chalk. Spin the wheel slowly again and see if it stops in the same place. Add some lead weight to the top of the wheel by wrapping it around a spoke or by taping it to the rim. Spin the wheel again. Repeat this and add or subtract weights until the wheel takes a long time to stop turning and will stop in any position. Fix the lead weights properly to the rim. If you wrap strips of lead around the spokes, wrap electricians tape or similar around the windings. Stick the strips to the rims with silicon and tape over the weights until the silicon has set. Fit wheel to bike.
« Last Edit: April 15, 2015, 11:40:02 AM by Lobo »

Offline JustcallmeMrT

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Re: How true is true?
« Reply #10 on: April 15, 2015, 12:20:25 PM »
Well that makes me feel good Lobo, seems I'm doing alright.  My 0.2mm was ignoring the weld.  Jumps around nicely at that point!  Now to get the rubber installed and I'll have a set of wheels!

Offline Bitsa (Ralph Wright - RIP)

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Re: How true is true?
« Reply #11 on: April 15, 2015, 01:48:47 PM »
Or clink clink clink clonk  ;D ;D
Cheers
Bitsa
Long Live Best Bitter.Status Quo and Sohc Bikes and common sense which you can not teach

Offline Trigger

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Re: How true is true?
« Reply #12 on: April 15, 2015, 09:25:10 PM »
Ting, Ting, Tong is only for those cheap Chinese spokes  ;D ;D ;D

Offline peterengland

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Re: How true is true?
« Reply #13 on: April 20, 2015, 05:22:14 PM »
I've never had an MoT yet where they even look at the wheels apart from tyre tread, is this not normal?
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