Is it worth buying a set of calipers just to measure brake pad and rotor wear? Is there another accurate way to measure those things? Or are there additional good reasons to own calipers for someone who maintains his own bikes (Canyon Aeroad with SRAM–also a bunch of older steel bikes)? (I’m not a passionate mechanic type but try to keep my own bikes in good shape.)
This might help Threaded #10: The unexpected non-cycling tools for the workshop
A decent Iwanson caliper might do the trick at a reasonable price. A decent set of digital calipers is a good thing to have around anyway in my opinion. You can get a decent one on Amazon for $30 usd
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Does anyone have an example of “teeth” that can be added to vernier calipers for this purpose that Dave mentioned in the podcast? Or just cheaper to buy the iwanson?
I use a digital calipers to measure pad wear but a micrometer to measure rotor wear because the parallel claws on the calipers will have difficulty measuring the worn portion of rotors. The Iwanson gauge I got from Amazon was not accurate enough to measure rotor wear.
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These might be interesting caliper accessories
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These are the ones I use.
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Have you used these. Probably the cheapest option but has terrible reviews for them cracking when tightening the set screw by multiple people.
https://a.co/d/eT7Us8B Appears more sturdy but similar option
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It’s literally the smallest set screw imaginable do don’t know why anyone would do any more than snug it up. The act of using the calipers seats the adapters into position already so the set screw just keeps them from falling off.
Apologies for the snarky response. That’s just me saying that I personally haven’t had any problems with them and you certainly can’t beat the price! I think it’s one of the cheapest things you can buy on the Park Took website.
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I use the Birzman pad and rotor wear tools:
https://www.birzman.com/products.php?uID=2&cID=4#down_00
Not precise, but simple.
Just bought a new Force group and it came with a piston spreading tool, which under closer inspection has two rotor width measurement slopts on it (similar to the birzman). Thanks sram.
i previously just used calipers on the parts of the rotor with the narrowest diameter, that way i can get around the portion of the edge of the rotor that doesnt wear as much.
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I use a caliper without any “accessories” to measure rotors. While Dave has a whole writeup about how it’s not the “right” tool, you can still get good enough measurements by either
a) measuring across the braking surface perpendicular as normal, but shine a light from the other side or use feeler gauges to see if it’s not wearing flat
or b) place the length of the jaws parallel to and in the center of the brake track, with the outer edge of the track in the gap at the base of the jaws.
Other useful things for calipers on a bike (that I’m sure others can add to, but here’s what comes to mind):
- Measuring ball bearings (there’s also gauges for this)
- Measuring screw diameter, pitch, and length (gauges work better for this, but calipers work)
- Measuring sealed bearing ID/OD/thickness.
- Measure brake pad material thickness (I usually eyeball it, but I think all the major manufacturer’s have published wear thicknesses)
- Depth of blind bolt holes (e.g. bottle bosses)
- Spindle lengths on square taper BBs. BB shell width
- Seatpost diameters
- Cassette / BB / etc spacer thicknesses.
- O-ring dimensions (again, gauges work better)
I have these too, they are a little fiddly, but considering how infrequently I use them, the price makes them a good option for a home workshop in my opinion.
I’ve just upgraded to Force e1 shifters and they now include a piston spreader that has with gauges for 1.55 and 1.7 widths. Well done SRAM!
I found the park DCA-1 to be very imprecise. Hard to get the same answer twice and difficult to get it square (since the tips are conical). I got a small analog micrometer, definitely an improvement, but I’d get a digital one if I had it to do over again. The analog requires math and counting instead of just clamping down and getting an answer.
IMO
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I have just the tool for you! Just bought it as I was sick and tired of my (cheap Amazon) digital micrometer always being out of batteries the few times a year I wanted to use it. So I went analog from Haas - ON SALE for $24.97 - less than the cheap garbage on Amazon. Part #09-0196, see 0-25mm Outside Micrometer, 0.01mm Graduation, Chrome Plated Frame. If you join their “winners circle” for $10 you get free next day air + additional 5% off - a great deal overall. The construction is entirely metal - no plastic bits that will degrade over time.
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If the attachments are not permanently affixed to the digital calipers, I am curious if you will be able to repeat the exact same position each time.
I went to eBay to find a micrometer to measure pads and discs. I found this one from MAC Tools for about $27 USD. The surfaces that contact the thing measured are clean and scratch free, and zero measures to be zero dead on. Everything on it moves smoothly.
It is a used tool, but I have found that eBay can be a decent place find good tools, with the usual caveats, of course. This was $27 USD and change.
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