Levo SL Gen 1 Having some issues with Shimano rotors made in China

[sdcoffeeroaster]

I decided to install Shimano 203mm rotors on my Tubo Sl that has code r brakes. I just could not get the centerline rotors to perform quietly. I used a 1.5mm shim to account for the 200 to 203mm rotor diameter difference. I had an RT66 that was made in Japan that I used for the front and have had zero issues with it. I didn't have a rotor for the back and after searching the internet, I found a good price on one at Commencal. But when I got it I found it was made in China. The stamping process must be different because it just didn't bed in easily and I had to take it apart multiple times because of excessive noise and poor rough looking wear. All the punched out areas (not laser cut) looked to be very distorted early in the wear cycle and it took about 100 miles to get it to look evenly worn and the noise went away around the same time.

That rotor and pad combo did not last very long and so I decided to upgrade to the rt76 thinking it was going to be of higher quality and made in Japan. Wrong on both counts. It was somewhat quiet during the initial bedding process but on the first ride acts like it was warping with very intermittent uneven wear. I had previously done a complete bleed and used a special tool to make sure each piston was moving very freely. I took a bit of time getting it all centered too before bedding. But the the rotor looks like it has multiple high spots and low spots around the punched holes. This will be the last time I try to use a punched rotor and will only buy laser cut ones. I'm going to try some magura laser cut rotors I bought a while back that are 2.0mm and only 180mm. My bike is very light at 38 lbs, I'm only 145 lbs and I don't really do a lot fast long downhills so I'm thinking the 180's might work for me on the back. They fit but I might have to re-set the pistons with a thinner bleed block if they don't have enough clearance when they heat up.

I know some don't have issues with the RT66 or RT76 but my experience so far with the last two I bought from China has now been very good.

 

[steve_sordy]

I can't comment on the Japan vs China sourcing, nor the laser cut vs stamped versions. (I had thought that all rotors were stamped out and then ground flat). But I have never seen that blueing pattern before!

 

[sdcoffeeroaster]

I can't comment on the Japan vs China sourcing, nor the laser cut vs stamped versions. (I had thought that all rotors were stamped out and then ground flat). But I have never seen that blueing pattern before!

A lot of brands laser cut their rotors which eliminates punching distortion. Yes looks like it got too hot to me. I was away from the start of my ride when I really got loud and had to really baby it back but I think it's now damaged goods for sure. I think brakes are the one part of mtn bikes I've come to really hate. I did learn how to properly bleed the SRAMs and it is a pain in the butt. And I had really good luck with the front brake and even ran Gorilla Ceramics on it which are still stopped well and dead quiet. These are not even the original brakes which were Code RSC and these are R's. The original ones (bike had 150 miles on it) had very colorful rotors a lot like this (SRAM centerlines) and squealed like dying animal. Many have counseled me to just give up on SRAM brakes but when they work they really work well.

The attached picture is the original rt56 as it was breaking in and you can see how much distortion there is around the punched marks that are not even touching the pads during braking. It took a long time for these to look broken in and quiet down.

 

[Mcharza]

If I remember correctly some Shimano rotors only fit organic parts. Have you checked yours or do you only use organic.

 

[sdcoffeeroaster]

If I remember correctly some Shimano rotors only fit organic parts. Have you checked yours or do you only use organic.

The rt56 and rt76 both take metallic but I am using resin pads on them both. You could even see how badly distorted the rt56 was around all the punched features. The rt76 didn't look that bad until I rode with it and then looked and sounded horrible the more I rode.

I just put the Magura 180mm X 2.0mm on and it bedded in like butter. Nice soft white noise sound unlike that rt76 rotor. Will try it on a ride tonight but felt so much better during the bedding...so much smoother.

 

[sdcoffeeroaster]

I can't comment on the Japan vs China sourcing, nor the laser cut vs stamped versions. (I had thought that all rotors were stamped out and then ground flat). But I have never seen that blueing pattern before!

I just realized that taking a photo of a glossy surface like a rotor in anything but an entire white room will pick up colors all around you. There isn't really any color in that rotor except some dark scuffing. I tried some other pics outside and it was even worse, lol.