Zimmermann rotor break in process

Post by **scot850** » 04 Jul 2021, 13:21

Has anyone read the Zimmermann rotor break in process on the supplied bit of paper at the bottom of the box?

They require multiple firm braking cycles from 100kph to 50kph. Then several more high speed braking cycles in 3-5 seconds but no hard braking? What do you consider 100kpk braking in 3-5 secs?

I have never done any heat cycles on any rotors EVER. Only issues I have ever had were with Zimmermann rotors and that was 2 sets on the rear of a 98 V70XC that were bad out the box. 2nd set I had turned and were fine after that. Only other issue was our son's XC70 with Volvo rotors (3 sets and a turn in 20,000km), I then replaced with Brembos and no issues since. According to FCP web-site Volvo rotors are made in China? Could this be an issue?

Curious on other opinions.

Neil.

Cookeh · Post by **Cookeh** » 04 Jul 2021, 14:32

Common practice here, from performance disc manufacturers, is 200mi of gentle braking to bed in the disc, followed by hest cycling to sort pads. This is specifically for performance discs and pads though, which are designed for the heat cycling and actually require it.

I've never heard if Zimmerman though, and have quite no idea where they fall on the performance/OE spectrum.

Post by **scot850** » 04 Jul 2021, 16:55

Strange you have not heard of Zimmermann. As far as I know they are a German company and supply some manufacturers with OE discs/rotors.

These rotors are just standard replacements. I am way past needing high performance brakes. I like Zimmermann for the anti-rust coatings they use with their rotors. For the most part they are a very good product.

The main issue I have with the speed braking is that I live in the middle of a city and the only roads where I can drive that speed are are about 10km away and is a main highway driven on by high speed idiots. I can't see what could possibly go wrong doing high speed sudden braking on a road like that?!

Neil.

Post by **kallekula** » 04 Jul 2021, 17:31

I have Zimmermann on my bmw. I didn't follow any break-in manual. Just drove like I've always done and they work gr8!

Post by **Eddystone** » 04 Jul 2021, 20:31

I have Zimmermanns on two of my Volvos. I read that paper, and I think I actually went through the motions in one car and not the other. I've never had any issues with either car, and they still look good. I thought they were a decent product at an attractive price. Being labelled "Made in Germany" attracted me because I have had problems with rotors made in China from more than one seller, some brand name. What I found was that the metal from which the Chinese rotors were made was not uniform or consistent throughout the casting. The result was that there were areas that were exceptionally hard which didn't wear at the same rate, and you end up with a rotor surface that is not flat. The Zimmermans (regardless of where they actually make them) seem fine.

Post by **BlackBart** » 04 Jul 2021, 22:49

Neil - I've generally done a similar bed-in process on most new rotors and pads, but I can usually find a quiet 2-lane frontage road with nobody on it.

xanthefin · Post by **xanthefin** » 05 Jul 2021, 00:02

I have done that couple to three times hard breaking from 100kmh to zero and you start smell the pads.

Post by **scot850** » 05 Jul 2021, 17:30

It is a distance thing. Only 100kph road is the main highway and it is busy all the time. To give a scale to get to other roads, Calgary is 40km in diameter and I live about 10+km from the edge of the city. By the time I get to a 100kph road I have hit probably 15+ traffic lights! Respectful braking it will have to be and crossed fingers. If there is a problem of course I followed the procedure.........!

Neil.

Post by **FireFox31** » 09 Jul 2021, 14:48

I used the Zimmermann rotor break in process since there's an interstate highway between the garage where I do my work and where I live. However, the darn rear rotors were both 15/1000" warped out of the box and, of course, didn't get better after 2000 miles of use. FCP helped me with the return, but it's annoying to do the job twice.

Post by **scot850** » 09 Jul 2021, 16:28

Yup, nothing worse than do-overs!

Strange thing is as I mentioned it was rears Zimmermann rotors on my V70XC that were also a problem!

Did a bit of driving a couple of days ago before the thunderstorms hit. Disappointing but the brake pedal feels a little dead with too much travel. Will try bleeding the brakes again. The it is off to the pros if it doesn't get better.

Neil.