Honda CBR 250 Forum banner

1 - 16 of 16 Posts

·
Super Moderator
Joined
·
6,924 Posts
Discussion Starter #1 (Edited)
Here's an easy way to measure brake pad wear, without having to do any disassembly:

1) Using a Dial Caliper, measure the brake disc thickness... on my bike this is 0.175" (4.45mm)
Note: The minimum service limit for the front disc is 0.140" (3.5mm)



2) After squeezing the brake lever to seat the pads against the disc, measure across the backing plates of both brake pads... here I have a measurement of 0.775" (19.68mm)



3) This last photo shows the measurement that was taken from a set of new OEM Honda/Nissin front brake pads, which is 0.710" (18.0mm)
For aftermarket brake pads, just measure the pad set when new and make a note of that measurement for future reference.



Next, I subtract the brake disc thickness of 0.175" from the measurement taken in step 2...

0.775" - 0.175" = 0.600"

Then, subtracting this result of 0.600" from the thickness of the new brake set...

0.710" - 0.600" = 0.110"

This result of 0.110" represents a 15% difference between the worn brake pad set, and that of a new OEM Honda pad set... so, I have 85% of the usable* friction material remaining on my front brake pad set.

* The CBR250R/RA Service Manual lists the brake pad service limit as being "to the grooves" that are cut into the friction material.



.
 

Attachments

·
Registered
Joined
·
1,881 Posts
Thanks Mike; I always just peeked at my pads with an inspection mirror because my head's too fat to fit between the wheel and body to peek around. :)
 

·
Registered
Joined
·
501 Posts
Yeah, I measure the wear with my eyeball-calipers. Physically measuring pad wear seems to me overkill, and not terribly useful. Regular use of the eyeball-caliper tells me at what rate I'm using them up, and when it's time to replace. Physically measuring only gives me a number.
 

·
Super Moderator
Joined
·
6,924 Posts
Discussion Starter #5 (Edited)
Yeah, I measure the wear with my eyeball-calipers. Physically measuring pad wear seems to me overkill, and not terribly useful. Regular use of the eyeball-caliper tells me at what rate I'm using them up, and when it's time to replace. Physically measuring only gives me a number.
True... as far as doing periodic inspections, all you need to do is look at the brake pads to gauge whether they are good to go, or are due for replacement.

That said, measuring them gives you a method to quantify their condition as it relates to mileage. Over the course of working in the motorcycle industry as a tech servicing & repairing customer bikes (many who only knew how to use one tool to service their bikes - an AMEX card) and back in the day as a factory test rider, I'd gotten use to measuring and quoting brake pad condition as a percentage of friction material remaining. Being able to relate mileage to the percentage of pad material remaining is very useful for forum discussions on the topic of brake pad wear... when you have meaningful numbers, everyone can be on the same page.
 

·
Super Moderator
Joined
·
6,924 Posts
Discussion Starter #7
Nice topic to have. Glad the images are working now. ;)
nice clear images now, incl thumbs & enlarge :)
Yeah, I tried to fix the attachments in the other thread yesterday, but for whatever reason I couldn't get it sorted out in that post. I ended up shutting down and re-booting my computer, and then re-loaded the pic's from my camera's memory card into a new iPhoto file. After the first couple failed attempts at fixing the attachments, I figured the easiest thing to do was delete the other thread and just start over with a new post.

What's pretty ironic about all this, and kind of funny, is that I had just put up the 'How to" thread on making images full size, a couple days ago over in the New Member Intro forum. :eek: ... Murphy's Law in action.
 

·
Registered
Joined
·
3,226 Posts
comment on method here; as in virtually all measurements
there is validity in any rational method, including casual competent
observation.. contrary to typical [good] advice, i typically dont
measure my tire pressure with a pressure gauge, rather
[based on a lifetimes experience, not some gift of god]
my habit is to check tires visually as i approach her
then to feel them as my weight sinks in plus when we
start moving and in those first stages of riding..

this habit is now just part of riding the motorcycle..

for specific measurements tho [brake pads etc] there is also
obviously and self-evidently rational reason for using concise
measurements.. there are different levels of 'knowing'
which are different for different people/minds and brains..
if you want to [say] keep a specific log of something
for some reason including for someone else or if like me
your memory retention is not that reliable [etc] then measuring
with whatever measurement tool incl for logging purposes is
obviously the preferred method..

if i suspected my tire pressure was down thru 'suck it and see'
then response would be to use a pressure gauge and note
rate of change if any.. this could include logging..

there is also the habit of mind which is a bit different for everyone
but valid for everyone, especially from their point of view..
while my ongoing method of checking/testing tire pressure [etc]
works for me as an experienced motorcyclist, i still suggest
my sons check their tire pressure at the garage etc
when refuelling.. i might mention that their front tire
'looks a bit low, how does it feel, better check it'
to both stimulate their brains to think about it and to feel
for its condition, plus to create the habit of checking
with pressure gauges..

best method is whatevers appropriate at that moment
and best potential resource is both or all of them..
 

·
Super Moderator
Joined
·
6,924 Posts
Discussion Starter #9 (Edited)
Over the course of the past year doing periodic visual inspections of the condition of my CBR's brake pads, I assumed that the front pads were now close to 50% worn, at just over 11,000 miles on the odometer. It wasn't until I measured them the other day that I realized my 50% assumption was wrong, and that they were actually at 85% remaining. Just goes to show that appearances can be deceiving, and not everything is as it appears to be. Obviously that's why we humans came up with ways of measuring and quantifying things... otherwise we'd likely still be living in caves, and hunting Wooly Mammoth's with big clubs and pointy sticks if our forefathers had decided that "guess-timates" were good enough. ;)
 

·
Registered
Joined
·
139 Posts
Over the course of the past year doing periodic visual inspections of the condition of my CBR's brake pads, I assumed that the front pads were now close to 50% worn, at just over 11,000 miles on the odometer. It wasn't until I measured them the other day that I realized my 50% assumption was wrong, and that they were actually at 85% remaining. Just goes to show that appearances can be deceiving, and not everything is as it appears to be. Obviously that's why we humans came up with ways of measuring and quantifying things... otherwise we'd likely still be living in caves, and hunting Wooly Mammoth's with big clubs and pointy sticks if our forefathers had decided that "guess-timates" were good enough. ;)
it seems to me that at 11,000 miles on your odo and only 50% of brake pad used based on your riding habits, id say that 22k they will be completely gone, so id say 18k-19k miles they should be needing replaced.
 

·
Super Moderator
Joined
·
6,924 Posts
Discussion Starter #11
Over the course of the past year doing periodic visual inspections of the condition of my CBR's brake pads, I assumed that the front pads were now close to 50% worn, at just over 11,000 miles on the odometer. It wasn't until I measured them the other day that I realized my 50% assumption was wrong, and that they were actually at 85% remaining. Just goes to show that appearances can be deceiving, and not everything is as it appears to be. Obviously that's why we humans came up with ways of measuring and quantifying things... otherwise we'd likely still be living in caves, and hunting Wooly Mammoth's with big clubs and pointy sticks if our forefathers had decided that "guess-timates" were good enough. ;)
it seems to me that at 11,000 miles on your odo and only 50% of brake pad used based on your riding habits, id say that 22k they will be completely gone, so id say 18k-19k miles they should be needing replaced.
85% of the friction material remaining @ 11,000 miles.
 

·
Registered
Joined
·
139 Posts
85% of the friction material remaining @ 11,000 miles.
it seems you don't use your brakes often then. mostly highway riding i guess? most of my ridings in the city and i am about halfway through a set of pads with 12k miles on my odo.
 

·
Registered
Joined
·
342 Posts
I apply this technique to my wallet to see how thick it is.

If there's less than a millimeter left I know it's time to visit an ATM!

:)
 

·
Registered
Joined
·
2,217 Posts
Here are my measurements at 14,000 mi / 22.500 km

MEASUREMENTS

Rotors
Front 0.176"
Rear 0.198"​

Pad wear (measured as installed across back of shoes when clamped)
Front 0.713"
Rear 0.920"​

New OEM Honda pads (pressed together, measured across back of shoes)
Front 0.709"
Rear 0.737"
WEAR CALCULATIONS

Front old pads = installed 0.713" - rotor 0.176" = 0.537"
Front wear = new pads 0.709" - old pads 0.537" = 0.172"

Rear old pads = installed 0.920" - rotor 0.198" = 0.722"
Rear wear = new pads 0.737" - 0.722" = 0.015"​

The front wear seems to pass the sanity test but I am wondering if I need to re-measured the installed thickness at the ear because only 0.015" of wear seems almost negligible. Of course I use the front brake more often and more aggressively but I also use some rear brake as well.
 

·
Registered
Joined
·
73 Posts
Over joyed to see the great responses and advise on the most important system on our machines: THE BRAKES

Everyone has a "technique" and as our senior members have demonstrated, and expounded upon, what works for you may be different from what works for me....... But making the time to this very important detail is literally a matter of Life and Death.

Inspection, inspection and more inspection!

Some of you may have calibrated "grip" and after a long road trip that incurred a lot of braking, can actually feel the pads or wearing.

As we are sponsored by Galfer and love sintered brakes with Copper, we can actually feel when the pads are at 50% or less, as well as doing a quick spin check on maintenance stands for rotor warp.

Another note worthy mention is your Brake Fluid! Please change it yearly or at first signs of microbiological contamination. I love meeting Motorcycle tour operators in other country's who have not seen the insides of a brake reservoir and then open the caps and freak out from the reservoir corroded and discolored brake fluid. YUC.

My son who has great eyes...he can see a warped rotor, just when someone else rolls the bike for him....It's freaky actually. My daughter on the other hand can't see if the rotor fell off, and as long as the engine starts, she's good to go.........ugh!

I thank everyone for they're input on this overlooked but extremely important Post.

Woot Woot!

Cheers
 

·
Registered
Joined
·
2,217 Posts
2012 CBR250RA

Front brake pad replacement at 18,000 miles. Front brake was feeling very weak, although some of that is subjective comparison to the monster stopping power of the dual 320mm 4-piston Brembos on my F800GT.





Measurements of pads pressed together, off the bike:

New pads: 0.656" / 16.71mm
Old pads: 0.502" / 12.75mm
Difference: 0.154" / 3.91mm
Wear per pad: 0.077" / 1.96mm
 
1 - 16 of 16 Posts
Top