Minimum legal brake disc width

**CDFloss** · 4th May 2009, 20:56

Hi folks. Can someone please tell me what the minimum brake disc width is to pass a WOF? I've searched around but havent been able to find any info on this topic. Is it a specific width, a range depending on original width, or a percentage of original width?

Cheers
Dave

**Pedrostt500** · 4th May 2009, 21:03

Check with your bike dealer, each manufacturer has a minimum disc width for each model, if you have a work shop manual for your bike the info will be in it, Ask on here as some one will either know what it is for your bike or have a manual and be able to look it up for you.

**Ixion** · 4th May 2009, 21:07

It is sometimes stamped on the disk.

**yod** · 4th May 2009, 21:09

Originally Posted by Ixion

It is sometimes stamped on the disk.

yep you should find '4.0' (for example) on the disc somewhere
minimum is generally around the 3.5-4.5mm mark

**Laxi** · 4th May 2009, 21:13

ask a bike shop? 1 of the hutt bike shops failed me for a warrant on this, they said any disk has to be 4.5mm min, didnt agree so went to vtnz passed warrant without a hitch

**CDFloss** · 4th May 2009, 21:53

Thanks everyone. Yup mine passed WOF but were borderline. I was going to ring and ask what the minimum measurement is, but thought I'd see if I could find out tonight on here. I'll take a look in my manual (don't remember seeing it in there though), and will check the disc itself.

Thanks again.

**The Pastor** · 4th May 2009, 23:34

its stamped on ur disc, mine are 3.5min

**LBD** · 5th May 2009, 03:11

Originally Posted by Laxi

ask a bike shop? 1 of the hutt bike shops failed me for a warrant on this, they said any disk has to be 4.5mm min, didnt agree so went to vtnz passed warrant without a hitch

But if the bike shop was the dealer for that bike and knew the specs for your model and the VTNZ station did not know the specs just thought they looked okay, my question is....Have you really made the best decision ignoring the advice of those who know?

Definately check your owners manual and on the disk and find the spec for disc thickness and allowed wear. Its your call from there...

**Owl** · 5th May 2009, 07:26

I think my manual is telling me porkies. Manual states 4.0mm (3.5mm minimum) though the discs have 4.0mm stamped on them. However they measure 4.5mm.

**LBD** · 5th May 2009, 16:59

Originally Posted by Owl

I think my manual is telling me porkies. Manual states 4.0mm (3.5mm minimum) though the discs have 4.0mm stamped on them. However they measure 4.5mm.

Speculating, 4.5 new, replace at 4.0, should have been replace before the 3.5 min.....but looks like you were right about the bike shop.

**Taz** · 5th May 2009, 17:20

Always use an impartial business for your wof's such as VTNZ etc as the bike shops have a vested interest in making you spend more money and therefore would probably fail things that would otherwise have passed.