Front disk is buggered

**Stickchick** · 12th June 2008, 21:36

My front disk is a little buggered. I have been told that it is 5 ml below the minimum which doesn't really sound like a lot, but being the learner it doesn't really set my mind at ease knowing something is wrong with my little EL.

However, how dangerous is it to ride my bike with this? Should I just park my bike up until I get it fixed or can I continue to ride it?

**McJim** · 12th June 2008, 21:43

By 5 ml do you mean 5mm? i.e. 5 Millimetres?

If so then they must surely be wafer thin. If not I'll shut up.

**Stickchick** · 12th June 2008, 21:46

The aren't currently 5mm. They are that much below the minimum that they should be to be warrantable.

**Gubb** · 12th June 2008, 21:46

If it were me i'd get it checked out straight away, Brakes aren't really something I think "Nah, she'll be right".

Better safe than sorry.

**McJim** · 12th June 2008, 21:52

Originally Posted by Stickchick

The aren't currently 5mm. They are that much below the minimum that they should be to be warrantable.

Yeah well the point I was making is that brake discs are barely 5mm thick when new which means all that's left is fresh air....mibbe 5 microns (micrometre) or somat?

**sinfull** · 12th June 2008, 22:04

McJim is right there ! 5mm is alot of disc to lose ! Unless there was a . (point) in front of that !
Get a second opinion lil lady ! sounds like someone might be trying to railroad ya into spendin money

**sinfull** · 12th June 2008, 22:18

Originally Posted by Stickchick

My front disk is a little buggered. I have been told that it is 5 ml below the minimum which doesn't really sound like a lot, but being the learner it doesn't really set my mind at ease knowing something is wrong with my little EL.

However, how dangerous is it to ride my bike with this? Should I just park my bike up until I get it fixed or can I continue to ride it?

More to yr question ! I think if you have a look at your disc and run your finger along it from hub to the outside you might find what they are talking about ! A ridge will form at the front lip of the disc which you should feel !

If your disc pads are relatively new there shouldn't be safety issues, the caliper piston should take up the slack ! It's when the disc is worn badly and the pads wear out as well, the piston may bottom out and not give the pressure you need for the breaks to stop ya !

Happy to be corrected by any techs out there !!! But the way i figure it if you are aware they may be wearing thin just keep it in mind and dont out ride ya breaks
!
Edit ; yr fluid may be running low also !!

**Stickchick** · 12th June 2008, 23:08

Originally Posted by McJim

Yeah well the point I was making is that brake discs are barely 5mm thick when new which means all that's left is fresh air....mibbe 5 microns (micrometre) or somat?

Mmm yes thats what I meant.

**MaxB** · 12th June 2008, 23:55

What you could do is get someone you trust to measure the disc rotor thickness with a micrometer in a number of places and compare those values to the manual. Some disks have the minimum thickness stamped on them. Measurement will confirm whether your discs should be replaced.

The other thing touched on is they may be out of true, that is they are warped or impact damaged. You might feel that as a pulsing at the lever.

There are a number of reasons manufacturers specifiy min. thicknesses. The main one is heat dissipation. Thin rotors heat up quicker and you can cook the brakes. Brake fade is not nice. Other risks like the pistons coming out too far or fluid leaking past the seals are possible but things are really bad when it gets to that stage.

IMO brakes are not something you can take chances with.

**Patch** · 13th June 2008, 05:02

The minimum thickness for a front disc is to be no less than 5mm.

The minimum thickness for a rear disc is to be no less than 4.5mm.

The tolerances are stamped on the disc (should be) They will need to be removed to be checked properly. If in doubt, remove them and have a reputable engineer do this, he will advise you whether they can be re-faced or need to be replaced.

Stock rotors are quite hard and last a long time. Unless you do alot of km's per year, or ran the pads right down and scored the disc it is unlikely they will need replacing. Get them seen too all the same tho.

**cowboyz** · 13th June 2008, 07:15

its alla bit techincal really.

On a EL250 if your riding is reasonably responsible and you are not jumping all over the brakes going into corners then you are not going to get brake fade. Take the advice and get someone you trust to measure the discs and if they are below tolerance then scout for some aftermarket rotors (freddys discs in waihi is a good place to start). I wouldnt stop riding it. Just be aware of it.

they have to get pretty thin before they crack but if they do crack it is a whole new world of trouble.

**CookMySock** · 13th June 2008, 08:23

Originally Posted by Stickchick

Should I just park my bike up until I get it fixed or can I continue to ride it?

We have to tell you "park it up", because if the disc split and shit itself and threw you at high speed we would never forgive ourselves.. and if it does split or crack, as cowboyz says, you will get a bad bad bad fright.

The reality is probably quite different though, and probably you might be ok for a week until parts arrive.

If it was my teenage sons' bike I would take his keys. "sorry dood."

DB

**The Stranger:Me** · 13th June 2008, 08:54

Originally Posted by Stickchick

My front disk is a little buggered. I have been told that it is 5 ml below the minimum which doesn't really sound like a lot, but being the learner it doesn't really set my mind at ease knowing something is wrong with my little EL.

However, how dangerous is it to ride my bike with this? Should I just park my bike up until I get it fixed or can I continue to ride it?

Umm, that was 0.5mm.
Whilst they are below spec, they are not dangerous.
Most of the old crotch rockets are running around at twice the speed you are capable of doing on that bike with the owners blissfully unaware that their disks are in worse condition than yours (yay the 250 laws)

There will come a time that this is a problem.
You may well fail a warrant, and should have at your last.
With any disk, as it wears, there is a potential for it to fail, however, as I pointed out, there are signs long before failure.
Heat disipation is another issue, however, this is unlikely to be a problem on a 250cc cruiser.

That said, one of the biggest issues when riding is your head. If in the end my answers don't put YOUR mind at rest there is no question really - you should replace it.