Rotor wear

[Sander23]

Sander23,

Yes, you can use your external lock ring in place of an internally splined lock ring. Shimano uses two types of rotor lock ring, "External" and "Internal Splined." Which lock ring a person uses is dictated by the axle, hub end caps, and restrictions in amount of space at the hub. If your hub uses an external lock ring, then yes, you can use it on any Shimano center lock hub that you buy.

External Lock Ring
View attachment 129310

Internally splined Lock Ring
View attachment 129311


Shimano Ice Tech Rotor on my Rise M20 with Noble TR37 wheels.
View attachment 129313

Close up of the external lock ring
View attachment 129314

From reading your posts, I see you are mainly interested in Shimano Ice Tech rotors. As you've noted, the magnet rotors are expensive. Last year I posted a technical article which details how to convert the cheaper Shimano RT-MT800 "Non magnet" rotor and turn it into a RT-EM810 magnet rotor.

The conversion process is quick and easy, but does require a metric thread tap and correct drill size. You will also need to remove the magnet assembly from a worn out RT-EM810 rotor and re-use it on the converted MT800 rotor. Here is the link to the article if you are interested in reading it:

Shimano Brake Center Lock Rotor Hack - Converting a RT-MT800 into a RT-EM810 magnetic rotor

Hello, This tech article will describe how to convert a Shimano "Non-Magnetic" RT-MT800 center lock brake rotor into a "Magnetic" RT-EM810 brake rotor. I hope you find this article useful. If your bike has Shimano brakes, you will have likely noticed there is a shortage of Shimano brake parts...

www.emtbforums.com

Very helpfull.
Ye I was also interested in some galfer rotors but if I have to get the rotor + cl adapter + magnet the I'm at the price of the expensive icetech rotors.

I dont have the magnets from an mt800 rotor bur I've found some magnets

Giant Speed Sensor Magnet für Centerlock Aufnahme

Original Giant Speed Sensor Magnet für die Centerlock Aufnahme. Mit Hilfe des Sensor Magnets ermittelt der Geschwindigkeitssensor wichtige…

www.elektrofahrrad24.de

BOSCH eBike Magnet Centerlock for Slim speed sensor, 9,58 €

BOSCH eBike Magnet Centerlock for Speed Sensor Slim Original Bosch Magnet Centerlock for measuring the speed of your eBike Function only guaranteed with ori

r2-bike.com

I have to figure out how that last one is installed

 

[Rod B.]

Thanks for this post. However, which of these rotors are specified on MTB's, or more relevantly since this an eMTB site, on eMTB's?

Irie,

Shimano doesn't make an eBike specific brake rotor, other than the EP6 series, Ice Tech Freeza "RT-EM810", center lock ring, brake rotor which comes with a magnetic assembly built into the rotor carrier. You can use any of Shimano's six bolt or center locking brake rotors on an eBike, however some are better than others in regards to the rotor's braking surface and especially heat dissipation.

 

[Rod B.]

Very helpfull.
Ye I was also interested in some galfer rotors but if I have to get the rotor + cl adapter + magnet the I'm at the price of the expensive icetech rotors.

I dont have the magnets from an mt800 rotor bur I've found some magnets

Giant Speed Sensor Magnet für Centerlock Aufnahme

Original Giant Speed Sensor Magnet für die Centerlock Aufnahme. Mit Hilfe des Sensor Magnets ermittelt der Geschwindigkeitssensor wichtige…

www.elektrofahrrad24.de

BOSCH eBike Magnet Centerlock for Slim speed sensor, 9,58 €

BOSCH eBike Magnet Centerlock for Speed Sensor Slim Original Bosch Magnet Centerlock for measuring the speed of your eBike Function only guaranteed with ori

r2-bike.com

I have to figure out how that last one is installed

Sander23,

Some magnetic adapters work better than others.

I currently own a Specialized Levo with TRP DH-R Evo brakes. TRP offers a 2.3 mm thick rotor. The 2.3mm thick rotor is ideally suited for use on eBikes. The 2.3mm thick rotor is more resistant to brake fade, warping and offers a longer service life.

My last bike was an Orbea Rise. My Orbea Rise came with a set of Shimano two piston brakes. I had a set of SRAM G2 brakes in my parts bin and switched the Rise over to the G2's. SRAM doesn't make a magnetic center lock brake rotor. At the time (Early 2021), I tried virtually every center lock magnetic adapter that was available on the internet. It was a Cinderella quest. None of the adapters I bought worked adequately with my Rise's Shimano EP800 speed sensor pickup. On rides, my bike would occasionally "Out of the blue" fault code and quit working. This was because the magnet adapter did not perfectly position the magnet in line with the speed sensor pickup. If a speed sensor does not receive a magnetic pulse from the magnet on the rotor, the bike will shut off. I eventually got tired of buying adapters.

I tried gluing a magnet to the rear rotor. This too was problematic. Neodymium magnets will temporarily loose magneticity when exposed to high heat and then regain magneticity when they cool off. I'd make a hot run downhill and at the bottom of the run, my bike would issue a fault code and shut off. Ten minutes later, the bike was fine. Here's the thing, gluing a magnet directly to a rotor offers no insulation between the rotor and magnet. You will note that most magnet adapters have some form of casing or other type of heat insulation to protect the magnet.

Long story short, I eventually gave up. I folded like a kite in a wind storm. Sometimes trying to reinvent the wheel does not pay off. I eventually switched back to Shimano four piston XT brakes and a RT-EM810 magnetic center lock rotor. I really, really, hated paying $80 for a Shimano Ice Tech rotor, but what the hell, the thing worked. Thus endeth the lesson.

As a side note, when it comes to mountain bike wheelsets, I will never again own a wheelset with center locking rotors. It's such a pain in the ass dealing with adapters and or, sourcing magnetic rotors. Six bolt rotors are plentiful, cheap, and the six bolt adapters work.

Flow Job - Cowboy Trail System, Las Vegas Nevada. Stopping is over rated....

 

[irie]

Irie,

Shimano doesn't make an eBike specific brake rotor, other than the EP6 series, Ice Tech Freeza "RT-EM810", center lock ring, brake rotor which comes with a magnetic assembly built into the rotor carrier. You can use any of Shimano's six bolt or center locking brake rotors on an eBike, however some are better than others in regards to the rotor's braking surface and especially heat dissipation.

I did not ask whether Shimano made eBike specific rotors.

Instead I asked:

... which of these [Shimano] rotors are specified on MTB's, or more relevantly since this an eMTB site, on eMTB's

 

[Arminius]

I did not ask whether Shimano made eBike specific rotors.

Instead I asked:

Well, somehow you did

 

[Shark58]

which of these rotors are specified on MTB's, or more relevantly since this an eMTB site, on eMTB's?

Nearly all of them. Mainly defined by the price of the bike and the target customer group.

As an example you can find Cube hardtail eMTBs (Reaction Hybrid) from ‘23 that come with Shimano BR-MT200 brakes and 180 mm SM-RT26 rotors front and back. Brakes don’t get much cheaper.

 

[Rod B.]

I did not ask whether Shimano made eBike specific rotors.

Instead I asked:

Irie,
I'm sorry, I misunderstood your question. I thought you asked which Shimano rotors are specified on eBikes?

"Which of these [Shimano] rotors are specified on MTB's, or more relevantly since this an eMTB site, on eMTB's."

Okay.....as to what Shimano brake rotors are specified on mountain bikes? Shimano offers 10 mountain biking specific group set/brake systems which are suited to various degrees of trail usage.

Shimano braking system components can be mixed, i.e. Deore rotor with SLX four piston calipers. However, Shimano's compatibility chart should be referred to before mixing braking components, i.e. brake rotors and calipers. As an example, some Shimano calipers use a narrow or wide brake pad which may not work well with certain rotors.

Shimano's ten mountain bike group sets consist of the following hierarchy with XTR being the highest component level:

Altus - Basic entry level, not ideally suited for mountain biking
Acera - Basic entry level, not ideally suited for mountain biking
Cues - Newly introduced for 2023 and will replace Altus and Acera group sets
Zee - Severe duty, freeride/gravity orientated group set
Saint - Severe duty, gravity orientated group set
Deore - Value priced, light trail, moderate duty group set
SLX - Value priced, same as XT but offers less ride adjustable brake features
XT - Rugged trail service, built like a tank, multiple ride adjustable brake features
XTR - Moderate trail service - ultralight weight Cross Country racing group set

Note that Shimano offers multiple rotors that fall within the 10 group sets. It can be very confusing to decipher Shimano's part number system.

When reviewing Shimano's braking systems compatibility chart, you will see multiple components the fall within a component group set. As an example Shimano offers the XTR group set which is denoted by the numeral "9." Within the XTR group set Shimano offers the BR-9100 caliper (Two piston caliper) and BR-9120 (Four piston caliper). This same principle applies to all the other numbers that you see in the chart.

In many instances you will see older part numbers that have been discontinued, however the "Old Stock" parts can be cheaply obtained and will work just as well as Deore.

When deciphering which Shimano component, i.e. brake rotor or caliper to buy. I find it important to first determine how the component falls within the ten group set hierarchy, and also the degree of service/trail usage which I plan to use the component on. From there I make my purchase.

Be safe,
Rod

 

[Shark58]

I dont have the magnets from an mt800 rotor bur I've found some magnets

You will have to make sure that the magnet fits your bike’s speed sensor/motor combination.

Those „rotor magnets“ you linked to are for two very different motors and speed sensors and will not work on both of those.

The differences to watch out for are magnet position (how far from center of axle), magnet thickness and magnet strength.

If unsure it’s always the safest bet to buy what was on the bike originally.

 

[Sander23]

You will have to make sure that the magnet fits your bike’s speed sensor/motor combination.

Those „rotor magnets“ you linked to are for two very different motors and speed sensors and will not work on both of those.

The differences to watch out for are magnet position (how far from center of axle), magnet thickness and magnet strength.

If unsure it’s always the safest bet to buy what was on the bike originally.

This is the original bosch magnet. Right?
BOSCH eBike Magnet Centerlock for Slim speed sensor, 9,58 € my bosch motor.

 

[Shark58]

This is the original bosch magnet. Right?
BOSCH eBike Magnet Centerlock for Slim speed sensor, 9,58 € my bosch motor.

If you have a Bosch smart system motor with a slim speed sensor, it’s the right magnet. If you have a different Bosch motor and/or different speed sensor, you’ll need a different magnet.

 

[Sander23]

If you have a Bosch smart system motor with a slim speed sensor, it’s the right magnet. If you have a different Bosch motor and/or different speed sensor, you’ll need a different magnet.

Yes but, gen 4 and smart are the same motors right.
It states Compatibility: BDU3XX, BDU4XX, BDU37YY

 

[Shark58]

Yes but, gen 4 and smart are the same motors right.

No, there is a CX gen 4 non-smart and a CX gen 4 smart. The smart motor has a 4-digit product code like BDU37xx. The main issue is how the speed sensor is mounted onto the frame. You need a magnet mount that fits that position.

Do you have a photo of your magnet on your bike?

 

[Sander23]

No, there is a CX gen 4 non-smart and a CX gen 4 smart. The smart motor has a 4-digit product code like BDU37xx. The main issue is how the speed sensor is mounted onto the frame. You need a magnet mount that fits that position.

Do you have a photo of your magnet on your bike?

View attachment 129398

View attachment 20231119_214903.jpg

 

[Shorty4]

I don't think that Shimano specify any particular rotor's, pads or disks for emtb's, if you have a look at new emtb's and ebikes in general there is a wide variety of brakes fitted as standard.
Personally I think that heavy emtb's and heavy riders need the best brakes possible.
I've seen lots of lower end/cheap ebikes with rim brakes and many more with small cable operated disks which is borderline dangerous as the cheaper bikes tend to be heavier and often the riders are either new cyclists or relatively inexperienced.
We have three emtb's and all came with RT66 rotors and either twin or quad piston calipers with resin pads.
I run metal/sintered pads on both of my bikes and the wifes still has resin pads as she only rides fire trails and roads where I'm into single track and downhill.

 

[Shark58]

View attachment 129398 View attachment 129399

View attachment 129397 View attachment 129400

That rotor looks like a Shimano Steps RT-EM600 (includes magnet) fastened with an external serrated lockring.

The speed sensor looks like the original Bosch speed sensor (not a slim sensor) which normally was mounted further forward on the frame together with a spoke magnet. In your case the bike manufacturer managed to mount that sensor near enough to the brake rotor to make it work with the pictured magnet. It could also be a slim sensor mounted inside a frame housing that Bosch makes for that purpose. Anyhow, given the position of the speed sensor/magnet pair I would stick to a Shimano Steps e-bike brake rotor because they all have the same distance between magnet and center of axle. The next higher end version would be a Shimano Steps RT-EM810, which utilizes ICE-TECH design but costs almost twice as much as your EM600 pictured below.

 

[Sander23]

That rotor looks like a Shimano Steps RT-EM600 (includes magnet) fastened with an external serrated lockring.

The speed sensor looks like the original Bosch speed sensor (not a slim sensor) which normally was mounted further forward on the frame together with a spoke magnet. In your case the bike manufacturer managed to mount that sensor near enough to the brake rotor to make it work with the pictured magnet. It could also be a slim sensor mounted inside a frame housing that Bosch makes for that purpose. Anyhow, given the position of the speed sensor/magnet pair I would stick to a Shimano Steps e-bike brake rotor because they all have the same distance between magnet and center of axle. The next higher end version would be a Shimano Steps RT-EM810, which utilizes ICE-TECH design but costs almost twice as much as your EM600 pictured below.
View attachment 129455

Yea but that's the thing, the icetech rotor with centerlock in 203mm is on offer now for 24.90€ I can't let that slide (thats the same price for rt em600).
While current icetech rotors with magnet are 50-60 euro

I think I have to try it out.

 

[Shark58]

the icetech rotor with centerlock in 203mm is on offer now for 24.90€

Which exact type and how will you mount a magnet to that rotor?

 

[Sander23]

Which exact type and how will you mount a magnet to that rotor?

Rt mt800 external lockring,

Could maybe get a magnet like this?Drill out the hole like a post above

 

[irie]

Irie,
I'm sorry, I misunderstood your question. I thought you asked which Shimano rotors are specified on eBikes?

"Which of these [Shimano] rotors are specified on MTB's, or more relevantly since this an eMTB site, on eMTB's."

Okay.....as to what Shimano brake rotors are specified on mountain bikes? Shimano offers 10 mountain biking specific group set/brake systems which are suited to various degrees of trail usage.

So a rehash of a previous post.

Tried to find to a list of top 10 or top 20 eMtbs (to see what rotors are specified on those bikes by 'manufacturers') but unsurprisingly without success ...

 

[Sander23]

I just bought these rotors. I will try to figure out what or how i will put a magnet. For this price i couldnt let it go.

RT-MT800 Center-Lock Disc Rotor

Features - Shimano XT Center-Lock Disc Rotor RT-MT800 Stable and versatile brake performance in the most demanding conditions High-performance and consistent brake performance New ICE TECHNOLOGIES FREEZA construction for...

www.bike-discount.de

 

[Shark58]

I just bought these rotors. I will try to figure out what or how i will put a magnet. For this price i couldnt let it go.

RT-MT800 Center-Lock Disc Rotor

Features - Shimano XT Center-Lock Disc Rotor RT-MT800 Stable and versatile brake performance in the most demanding conditions High-performance and consistent brake performance New ICE TECHNOLOGIES FREEZA construction for...

www.bike-discount.de

Good price and I‘m sure you noticed that this close out deal comes without the original packaging. Check for blemishes.
Keep us posted how you dealt with the magnet.

 

[Sander23]

Got the 5 euro bontdrager spoke magnet. I diddnt use the spoke holder that it came with but bolted it in the hole using a couple of washers . Magnet isnt moving, going to add some loctite to the thread so it doesnt come undone. Now I have to test it

 

[Shark58]

Now I have to test it

Does this leave you enough space for the nut needed to fasten the external lockring? Looks rather close and you might need to remove the magnet and put it back on after fastening the rotor to the hub.

 

[Sander23]

Does this leave you enough space for the nut needed to fasten the external lockring? Looks rather close and you might need to remove the magnet and put it back on after fastening the rotor to the hub.

 

[Shark58]

@Sander23
I had a nut for my torque wrench in mind because I don’t know what 40Nm feel like.

Great solution with that magnet.

 

[Rod B.]

View attachment 129750

Sander23,

The magnet looks like a great work around. Please keep us updated on how it works out.

 

[Montana St Alum]

I got this with my Giant Elite 3. I think TRP sells them in both centerlock and 6 bolt. This just goes under the centerlock.
I'd guess a Giant dealer could order one if they're not in stock.
Modern bike has some made by Bosch.