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PostPosted: Sat Sep 07, 2013 12:49 am 
Gold Trader
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Joined: Wed Jun 20, 2007 11:19 pm
Posts: 7006
Location: Odense, Denmark
EN standard is actually horrendous - 0.5 mm lateral....

Anything below 0.1mm is quality- and requires some serious hardware to gauge correctly.

Pulsing MAY not be the rim though.

I've seen this before on some fork/brake combos where it turned out that either the brake or the fork was actually at fault.

I've also seen defective rims with incorrect extrusion that had similar symptoms and which were also impossible to correct.


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PostPosted: Sat Sep 07, 2013 9:08 am 
Dirt Disciple

Joined: Wed Mar 27, 2013 11:37 pm
Posts: 93
Location: Bristol
Thanks for the feed back, I'm heading back to the LBS shortly....

Re JohnnyBoy666 - questions
- no the bike wasn't purchased from them.
- The wheel was new to me and hasn't seen much abuse (the MTB's are for that)
- The wheel is maybe 3 years old,
- It wasn't too bad when they got it, I have seen worse straightened!
- I'd stripped it down to the rim to make it easy for them.

Fingers crossed I get a satisfactory service this time round....

JT


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PostPosted: Sat Sep 07, 2013 9:28 pm 
Old School Grand Master
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Joined: Fri May 01, 2009 7:11 pm
Posts: 8479
Location: Fircombe.
monty dog wrote:
British Standard for new bikes is something like 2mm lateral and 5mm radial - any competent mechanic would consider any visual deviation to be unacceptable.

5mm radial, like an eccentric clown bike wheel?

The OP mentions a buckle. If it's buckled, no amount of trueing is going to help, but they should have known that...


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PostPosted: Sun Sep 08, 2013 8:27 pm 
Retro Guru

Joined: Mon Feb 01, 2010 8:57 pm
Posts: 774
Yup, 5mm radial seems ridiculous, but I distinctly remember this from my time as a shop mechanic - there were some bike makers who were very obviously building to this spec too. Shop owner was a bit peeved when I'd true the wheels on cheapo MTBs 'properly' - problem was. spokes were made of mild steel as stiff as spaghetti and rims were made of soft alloy like cheese.


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PostPosted: Sun Sep 08, 2013 8:58 pm 
retrobike rider
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Joined: Fri Aug 08, 2008 2:36 pm
Posts: 16748
Location: Yorkshire, England
I still cannot believe them.
A Shimano V-brake is properly setup with 1mm each side of the rim. With 2mm tolerance you'll be hitting the rim... It doesn't add up.

And vertically you'll have problems of pads hitting the tyre as you're suppose to setup up with 1mm clearance from the top of the rim.
5mm will take you off the rim.

0.2mm ↔ and 0.5mm ↨ do sound far more like it you can still see this 'wobble' by eye. It's a usable and achievable spec.

I've made a search for the spec but cannot find anything on it yet. Any idea what I should be looking under ?


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PostPosted: Sun Sep 08, 2013 9:06 pm 
retrobike rider
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Joined: Fri Aug 08, 2008 2:36 pm
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Location: Yorkshire, England
ok search a bit better now.
For the sale of a bike
[i]There are several standards that need to be applied when selling new bicycles in either partially or fully
assembled form. These standards must be used in conjunction with each other and apply to all sellers of
bicycles.

The standards that manufacturers and distributors work towards are; British Standard BS6102 Part 1 1992,
and European standards BS EN 14764:2005 City and Trekking Bicycles, BS EN 17466:2005 Mountain
Bicycles, and BS EN 14781:2005 Racing Bicycles.
BS 6102 Part 1 1992 is as follows (supplied by ACT & BSI)[i]

...
2mm radial and lateral for rim brake
4mm radial and lateral for disc brake

That is from a guide not the BSI


I believe they are superseded by
BS EN 14764 Bicycles for use on public roads (includes city and trekking bikes)
BS EN 14766 Mountain-bicycles
BS EN 14781 Racing bicycles
BS EN 14765 Bicycles for young children.

but I'm not paying the money to look at them. I assume bike shop owners will have these ?


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PostPosted: Sun Sep 08, 2013 11:41 pm 
Old School Grand Master
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Joined: Wed Apr 12, 2006 12:33 pm
Posts: 11106
Location: The Home Of Mountain Biking, And All Great Things.
The CTC 'Bike MOT' specs are:
"6.2 Rotational truth
If the wheel is used with rim brakes, its runout (total range of apparent movement when
rotated) shall not exceed 3mm either laterally or radially.
If the wheel is not used with rim brakes, its runout shall not exceed 5mm either laterally or
radially."
3mm is perfectly fine for me on MTB wheels. If you have your pads so close to the rim you are going to get contact on cornering, etc.
With discs it really doesn't matter so much, rims are only one part of the equation, and the tyres are much less consistent than anything else. Pay more attention to tracking and things like that that most people often ignore.


Last edited by highlandsflyer on Sun Sep 08, 2013 11:56 pm, edited 1 time in total.

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PostPosted: Sun Sep 08, 2013 11:48 pm 
Anglian Deputy AEC
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Joined: Mon Oct 09, 2006 6:13 pm
Posts: 6928
Location: Livin' in a dust bowl
My local roadie LBS charges £10 per wheel but you get free re-trues for life. Going back to the original question I think Cytech quote 1mm lateral or vertical play is within tolerances. Personally, when I build a wheel I end up getting bored with endless tweeks to get the spoke tension even and the wheel as true as it I can get it. Get to a certain point and make do with it.


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PostPosted: Sun Sep 08, 2013 11:58 pm 
Old School Grand Master
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Joined: Wed Apr 12, 2006 12:33 pm
Posts: 11106
Location: The Home Of Mountain Biking, And All Great Things.
I spent my youth slackening off spokes and leaning on rims to straighten them up.

Never needed to be so exact. Then I was riding racers off road.


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PostPosted: Mon Sep 09, 2013 12:35 am 
Retro Guru

Joined: Sun Jun 20, 2010 4:39 pm
Posts: 1455
i've always built my wheels.......never worried about standards or anything, just as true as i can get before i loose intrest and say "that'll do"
but they are always with in a mm both ways. does this make me...an uneducated self builder, good enough to build for a lbs? hmmmm???


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