Brakes Wheels 1st Gen Tires Most liked posts in thread: Rotor thickness question.

Kieth you are a pill sometimes! Neither mini_racer or myself said to use the style caliper for brakes in our posts. It was a joke ( a story with a humerus ending). Read my post to Jerry along with mini_racers subsequent response and then followed by Jerry's.... about I.Q. Have some humor sometimes relax.

BTW a good mechanic can use one pictured and come up with the exact reading as the correct style for disc measurements. Oh but I am a good mechanic. LOL Think gum?


Also refer to my post #3 about Vernier Caliper.
http://www.tresnainstrument.com/product/vc10.html

To Jerry:
Yes Jerry that would be one of many.

 

Be sure to get one with a shorter post. The opening on the OE rotor heat shroud won't allow a tall post behind the rotor.
Fowler 74-860-434, Electronic Extended Range Disc Brake Micrometer - DJV Merchandise.com

 

I guess I'm cheap...

I use whatever measurement tool I have around, cheap caliper, mic, small steel machinists rule, whatever. Way I figure it, if it's close then toss it anyway as it will wear during use anyway.

But then that's the difference between physicists and engineers. Physicists want the concept right, engineers want to use lots of decimal places!

Matt

 

Make sure you have sufficient thickness to have a usable rotor thickness after turning, if its near the minimum it will not take long to be below it.... 2cents

 

Fact not opinion,

the specifications are in the disc/rotor to show the minimum safety measurements as per the manufacture to machine them. This is not for reference indicating wear. Machining them to the minimum specification has no bearing on efficiency or increase/decrease in wear.

This is actually a question on the ASE Certification Brake Technician test. lol

 

Right, so the Min thickness spec is for the purpose of resurfacing the rotor. It is Ok to resurface the rotor down to the min thickness, but of course that will be the last resurfacing possible on that rotor.

In my experience a rotor used for the street can get resurfaced once or maybe twice if you are lucky and still be above the Min thickness spec.

Racers and serious track rats almost never get rotors resurfaced, they just swap them out with fresh stock.

 

Do you think this rotor is still thick enough?

I'm concerned cause it sure made a racket.

 

I have some fresh Jb weld that will fix you right up.

 

You can get new rotors ( for a little bit more than turning your old ones).

Zimmermman Rear $38.57
Zimmermman Front $53.94

So you don't have to worry about min thickness or life left in your rotor. Just my 2 cents

 

Hey Roberto, those are great prices on stock replacements.

 

I'd get new one's... 2 cents

 

Hmmmmm....
Never realized disc's had such minimal wear life. 1.44mm, in merican that's .056" (less than a 1/16" of wear). So less than 1/32" per side. Almost seems like any attempt to turn down the disc's puts you in the "buy new" category.

 

That's MINI's take on the subject of rotor wear.

I did go almost 90k miles on the first OEMs.

Mark

 

Oh Sh!7, TSWs How did that happen?:confused5:

 

The days of turning rotors is gone. Buy new ones.

Sent from my Droid using Tapatalk

 

Brake Rotors or brake disc's do not wear down but get wear patterns needing to be turned/machine out at every brake pad change. It is not uncommon to see very little usable specifications with some manufactures or type of rotor/disc used. If you are close enough to the minimum specification only by measuring them on a secure rotating mill or similar locking device can accurately measure to determine if cleaning by way of machining within the specification can be successful.

All new rotors or disc should be resurfaced and clean machined prior to installing. However this practice is a dying procedure because of economics. Most are not willing to pay an additional $14-20 each to have this done on new rotors or discs? It is well worth paying the charge to have them done because of the surprising number that do not measure true coming new out of their box! You can't stop you MINI dragging your feet as Flinstones do if a brake part fails or the performance is reduced by being cheap?

 

A little over 2 years of one weekend a month at the track.

 

The min thickness spec is for machining. If they are smooth at 20.8 then no need for turning, just run 'em.

If you want to get them turned, then fine. Get them turned as little as possible, the shop will go as far down as the min thickness and no more. Use them until they get grooved, etc.

It should be no more than about $10-12 per rotor, if you bring them in to a machine shop.