disc wear

Hi good folks,
I know that mother Honda says we should replace the disc's when they get to 6mm, how important is that, the cost of new all round, here in the UK is the best part of ?430 from Honda. What are the implication of say, wearing them down to 4.5/5mm

Thanks

Maybe the disk cracking under hard braking, the bike not stopping and you dieing.

Simple logic should tell you that it will take longer for the pistons to move the calipers to the point of useful braking ability. Less mass to dissipate heat increases probability of warping, theoretically anyhow. I think you have a type of inspection on that coast of the Atlantic, what do they have to say ? I tend to ride in the style that I don't use the brakes very often, but I sure want to know they are still "up to the job" when I go for them. If you use them a lot, which appears to be the case, I'd be shopping now for the best deal.

thebigone said:

I know that mother Honda says we should replace the disc's when they get to 6mm

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Did you mean to qualify that? By that I mean, the Service Manual has different "Service Limit" values whether it's the front or rear discs.

For my 2003 S.M., "Standard" thickness is 5mm, "Service Limit" is 4mm for the front, 7mm and 6mm respectively for the rear.

caldercay said:

Standard" thickness is 5mm, "Service Limit" is 4mm for the front, 7mm and 6mm respectively for the rear.

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your right I'm wrong sorry,:bow1: same question. My rear is down to about 5.5mm if I remember from last week, and I appreciate the heat issue, not to sure about cracking. Is it something that is checked by one and all, not all can afford to take their bike to a dealer or work shop,
I will however be getting a new rear with pads (oem) next week

Personally I'd just ride....maybe replace pads more often...............as long as it isn't warped or feels uneven..................ff

The main issue you would have is that a thinner disk will warp easier, especially during spirited riding (lots of hard brake use). The theory of the pistons taking longer to contact isn't an issue because they are self adjusting and will grab just as quick regardless of the thickness. I would just ride it, and pay attention to any warping issues. If you feel lever/pedal pulsing get new rotors.

For the 1100 I believe aftermarket rotors are available much cheaper than Honda. I haven't seen that option for the 1300.

What happened with my rear disc at +/- 125,000 miles is at about 6.2 mm thickness the pads reached a point of wear thin enough the metal backer plate for the pad began to contact the original disc thickness with a Bad Noise. The pads wear the disc down leaving a raised ridge around the inner and outer edge of the machined surface. New pads would have bought more time but I replaced the disc.

New rear disc, nut's and pads from mother Honda ?176. going on this weekend

dduelin said:

What happened with my rear disc at +/- 125,000 miles is at about 6.2 mm thickness the pads reached a point of wear thin enough the metal backer plate for the pad began to contact the original disc thickness with a Bad Noise. The pads wear the disc down leaving a raised ridge around the inner and outer edge of the machined surface. New pads would have bought more time but I replaced the disc.

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I can vouch for this. Just changed out rear pads tonight and noticed the same thing as Dave describes. I've got 138K on the rotor, looks like its time for a new one