Suggestions: Brake Rotor Caliper or Micrometer

[nafterclifen]

Looking to purchase something inexpensive to measure brake rotor thickness. Not going to be used daily, weekly or even monthly - more like yearly at most. I'm partial to digital but would consider analog if quality and price are superior.

Long-reach caliper or micrometer? Suggestions?

This is what I'm considering - https://www.amazon.com/gp/product/B006Y1OWKS/?tag=atomicindus08-20

 

[rsanter]

Those will work just fine.
Take the batteries out when not in use if you are only using these a couple times a year

 

[joe_pinehill1]

a micrometer would be a better tool, to avoid the lip of rust at the perimeter of the disc. I found one at a yard sale years ago, a retired machinist, got mine for $1

https://www.amazon.com/dp/B0045VKF5K/?tag=atomicindus08-20

 

[kythri]

a micrometer would be a better tool, to avoid the lip of rust at the perimeter of the disc. I found one at a yard sale years ago, a retired machinist, got mine for $1

https://www.amazon.com/dp/B0045VKF5K/?tag=atomicindus08-20

The calipers he posted above address the lip issue. Check the link.

 

[Kaervak]

Looking to purchase something inexpensive to measure brake rotor thickness. Not going to be used daily, weekly or even monthly - more like yearly at most. I'm partial to digital but would consider analog if quality and price are superior.

Long-reach caliper or micrometer? Suggestions?

This is what I'm considering - https://www.amazon.com/gp/product/B006Y1OWKS/?tag=atomicindus08-20

I have a non digital version of that type of caliper. Works just great and was super cheap compared to its digital compatriot.

 

[SKFengineer]

To me it's about significant digits. What I mean is a caliper is typically good for two to three decimal places depending on the brand and quality. Micrometers are typically good to four decimal places. What is the requirement of the rotors to know if they are in or out of specification? I agree with others about avoiding the rust and material outside of the wear path but I'll assume you know that.

 

[bwringer]

Crikey, you ain't building space ships. Get the cheapest possible digital caliper from Harbor Freight.

https://www.harborfreight.com/4-in-digital-caliper-63710.html?_br_psugg_q=caliper

Notice there's sort of a "cutout" near the base of the jaws; this will allow it to easily get a reading past the lip at the edge.



Or, grab their digital micrometer. This thing is actually quite skookum and many times more accurate than you need. Just remove the battery between uses.
https://www.harborfreight.com/digital-micrometer-63647.html?_br_psugg_q=micrometer

 

[dadsEH]

To me it's about significant digits. What I mean is a caliper is typically good for two to three decimal places depending on the brand and quality. Micrometers are typically good to four decimal places. What is the requirement of the rotors to know if they are in or out of specification? I agree with others about avoiding the rust and material outside of the wear path but I'll assume you know that.

One decimal place.

 

[sberry]

With a little observation a guy can look at a rotor and tell if its worthy of a set of pads. I had one of my own did some work to a while back and compared to another I had replaced a while back was obvious. New one was 1/4 or so, maybe more and the other that was oem was 1/8. The car was about A year old and **** a factory pad, maybe just off warranty I don't remember but ground a coupe of rivet grooves in it. Not sure the jobber even had a rotor on the shelf but I put a set of pads on it, maybe twice and bought a rotor which I had on the shelf, at about 140 on the clock used it with a new set of pads. So I used used pads on the other old rotor for another 20 K and finally had a problem, maybe caliper and splurged on a new rotor for the other half set of pads I still had.
I am thinking this to outlast the car.

 

[bargainhuntingking]

This is what I use:


Bought specifically for that purpose. Cheap with a HF coupon. It works just fine. Item #60248

Tip: remove the battery after each use or it will drain.

 

[nieuport17]

I have both.
I end up using micrometer the most, just because its easier for me. I take the battery out when not in use.
Make sure you grab the right micrometer with the long reach version, something like this one :

https://www.harborfreight.com/6-in-long-reach-digital-caliper-63714.html

This not what I have, just an example.

 

[SJ Lurker]

Those long-reach calipers look pretty cool; I hadn't seen those before.

I used a micrometer. Make sure you get the right measuring range. For example, in my application with thick brake rotors, a 1"-max micrometer would be too small. A digital readout is handy.... but you get used to reading the dials very quickly.

Another advantage of a micrometer is that I could measure rotor thickness through the spokes of my wheel. That is, no need to lift the corner of the car and remove the wheel. Sometimes you just want to track rotor thickness, to get an idea of when you would need to purchase or replace rotors. [If you track your car, replacing rotors is a regular maintenance procedure.]

[Wow, I really am a lurker.... First post in 7 years!]

 

[Jbullfrog]

I bought my Blue-Point digital rotor caliper at a pawn shop for $25. They aren't a fast mover and a battery is usually the only problem.

 

[paulsomlo]

You can buy used 0-1" micrometers all day on ebay for $10 or less, shipped.

 

[2ndGearRubber]

Looking to purchase something inexpensive to measure brake rotor thickness. Not going to be used daily, weekly or even monthly - more like yearly at most. I'm partial to digital but would consider analog if quality and price are superior.

Long-reach caliper or micrometer? Suggestions?

This is what I'm considering - https://www.amazon.com/gp/product/B006Y1OWKS/?tag=atomicindus08-20

I actually own those. Been good for my rotor mic uses for the last few years.

 

[sberry]

[If you track your car, replacing rotors is a regular maintenance procedure.]

I don't track or replace as regular maintenance, I take the wheels off at the first sign or earlier of a problem and fix, unstick, inspect etc. Most brake problems are not really worn rotor but worn pads and stuck parts especially caliper pins and slides if a guy lives in less than pristine environment.

 

[sberry]

If there wasn't a spec many people would simply run them till they wore thru rotors or drums. Minimum thickness was to insure,,, in theory anyway that it would last thru another set of pads or shoes back in the day. Was and still is no skin off the mfg and the parts guy to replace it at every chance.
There is some obsession with rotors on the forum but making sure its working is way more of a deal than a few thousands wear, making sure there is some pad left and that its not separating, that its running square.

 

[davethorik]

I think he meant track as in race track, lmfao

 

[bwringer]

With a little observation a guy can look at a rotor and tell if its worthy of a set of pads...

Excellent point. In the end, measuring rotor thickness really is fairly pointless.

If it's not your first pad slap, it's quite obvious when it's time to replace rotors.

 

[Citation]

You might consider something like these pinch calipers
https://www.amazon.com/dp/B002PU77Q8/?tag=atomicindus08-20

 

[Leaflessshadetree]

Before worrying about thickness I'd to check for warping/flatness and any surface damage. Measuring thickness is important if you are determining if they are thick enough to turn.
These days it's usually less expensive and more convenient to replace rotors.
If a visual inspection shows the rotors need work, why measure anything?

 

[Lassen Forge]

Um. real world, I have a metric steel rule I check brake linings with, IF they look questionable, but at that point it's like, well, replace them anyway. But if I need to justify I record what my mm ruler tells me those pads are.

Serious... pads VS rotors? Not EVEN a toss-up. If they're that close (like 1/8" or less) and you're not replacing them, then trade your car in for a Kia... and call the dealer to service your cars... OR learn what is servicable and what isn't.