Rotors for 2-piston Shimano BR-MT410 extremely limited?

[Chazmo]

and a torque wrench

Ooh, Base, that’s an interesting point. I’ve never used a torque wrench on my bike… But, for the record, I have yet to find a torque rating for anything on my Juiced bike except the torque sensor mounting bolts in the rear dropout (where it’s clearly marked). That’s a little ironic, don’t you think?

 

[Base]

Both IS2000 and Postmount have a industry standard Torque spec. 6.8-7.2Nm

Bolts for the IS rotor would go at 6.2Nm or based on the Hubs-spec.

That kind of info should be in the manual or in my case, in my head. Use them daily

 

[stompandgo]

I use the following for unspecified hex socket head screws/bolts/axles:

2-3mm: 3Nm
4mm: 4-5Nm
5mm: 6-8Nm
6mm: 8-11Nm

I use the low side for titanium fasteners, and the high side for robust fasteners. It's not gospel, and if there is a spec, I use it.

 

[Shifty Shane]

My ebike came with 160mm front rotor (it's got 180mm at the back for some reason) which I find small for the weight, motor, speed characteristics. I want to upgrade, once, and go with 203mm.
To my surprise, the BR-MT410 2-piston calipers are extremely limited in rotor options, or so does Shimano want you to believe?
These calipers support only the so-called "WIDE" pad type, which in turn only supports specific rotors (as listed in Shimano's compatibility chart, mostly rotors on the cheap end apart from a SM-RT30 centerlock which doesn't work on my 6-bolt setup anyway) and will result in less contact area between pad and rotor. As I understand it, these pads are slightly higher than the pads on 4-pistons, and so need a larger contact area (in terms of height/contact diameter) on the rotor to work as they should.

https://productinfo.shimano.com/en/compatibility/C-461

Shimano BR-MT410 2-piston


I want to install a decent MDR-C 203mm rotor from Magura, not after top performance racing stuff but neither entry level ones, like the one in the link. I believe most non-Shimano rotors are similar anyway in how much contact area they offer to the pads, but apparently these will not work well with my caliper and pads type/shape. Is that really true? If so these must be the most pointless calipers to get on a bike: More expensive than the basic models, but a bit cheaper than full 4-pistons, still only compatible with the cheapest entry level rotors, why bother?

https://www.magura.com/en/EUR/bicycle_tuning_&_spare_parts_rotors_rotor_mdr-c/p/mdr-c

Or that's all Shimano marketing and I should go ahead and buy any aftermarket 203mm rotor?

I received the Tektro TR203-52 rotors and E10.11 pads, the outer rotor brake pad contact area is approx. 17mm vs the SRAM Centerline RT-CLN-A1 203mm rotors which were 13.5mm. In the pics, the brake pads align with the contact patch on the Tektro rotors, you can see the brake pad overlap on the Centerline rotors which require the narrow pads and 4 piston calipers. I believe the Magura MDR-C is also compatible with the B05 brake pads that fit your BR-MT410. calipers.

 

[juggernaut1]

I have 203 MDR-C rotors on my eMTB.

On my other ebike I upgraded my Tektro HD350 brakes to Shimano Icetek RT86 rotors (upsized 203 front and same 180 rear) with Tektro P20.11 pads from the junk E10.11. After the upgrade I felt confident the bike was actually going to stop from higher speeds.

Both are great rotors, but the Shimano’s might be cross compatible with your existing system.

 

[Shifty Shane]

I have 203 MDR-C rotors on my eMTB.

On my other ebike I upgraded my Tektro HD350 brakes to Shimano Icetek RT86 rotors (upsized 203 front and same 180 rear) with Tektro P20.11 pads from the junk E10.11. After the upgrade I felt confident the bike was actually going to stop from higher speeds.

Both are great rotors, but the Shimano’s might be cross compatible with your existing system.

I was thinking of getting the P20.11 pads, I figured the E10.11 will at least be an improvement over the OEM A10.11 pads that my bike came with. Are the P20.11 quiet, no squealing like some sintered metallic pads.

 

[Shifty Shane]

I have 203 MDR-C rotors on my eMTB.

On my other ebike I upgraded my Tektro HD350 brakes to Shimano Icetek RT86 rotors (upsized 203 front and same 180 rear) with Tektro P20.11 pads from the junk E10.11. After the upgrade I felt confident the bike was actually going to stop from higher speeds.

Both are great rotors, but the Shimano’s might be cross compatible with your existing system.

I was looking at upgrading to 203mm 2 piece rotors, but I thought they were all designed for 4 piston calipers with the narrow style brake pads. Most of the ones I looked at said the 2 piston calipers with the wide style brake pads weren't compatible due to clearance between the caliper and the rivets holding the 2 pieces together. It looks like the SM-RT86 has the rivets further inboard, so no worries of caliper interference. Next time I replace my rotors, I'll try out the Shimano SM-RT86 with Tektro P20.11 pads.

 

[Ringo9]

Thanks @Shifty Shane, @Base and everyone else ( I'm bad at multi-quoting from several pages ) So...

Reading an earlier post saying most aftermarkets rotors in a shop measured around 17mm contact patch I went ahead with the MDR-C Maguras and... as I was afraid, their contact patch at the lowest point measures at most 12.5mm... That leaves a good 3.5mm of the B05S pads sticking out as they measure ~15,5mm high (vertically). However as you can see from the pictures this "contact gap" varies from 3.5mm down to 0 (full pad cover) as the pockets on the Maguras are a varying size shape. I wonder whether this constantly varying contact area during braking (as the wheel turns) will a) be felt / heard b) reduce the expected stopping performance or c) won't make any difference apart from looking not sized correctly to the trained eye...

PS. Thinking about possible performance impact: Magura actually sells pads that match these exact rotors. Those pads are made also for 2-piston calipers (but from Magura) so it's just 1x left and 1x right, and are shorter in height than the B05S. That means the contact area is not larger than the one I am getting now with Shimano pads and they are supposed to work fine. That must mean that the only possible side effect is either noise or a varying wear on the pads? but with the wheel turning it shouldn't be the case? I wonder if anyone has tried this combo before. I really want to keep them and try them but that will void any return...

 

[Chazmo]

@Ringo9 the shape of that Magura rotor is very interesting. Your measurement isn’t accurate because it’s only 12.8mm at its thinnest point. That's not a ring; it’s kind of a wave with more or less surface area as it rotates, not to mention the varied sizes of the holes. I think you’ll be fine. I’m not sure what the performance will feel like. Could feel pulsating. Don’t know, and not speaking from experience here.

Good luck.

 

[Ringo9]

@Ringo9 the shape of that Magura rotor is very interesting. Your measurement isn’t accurate because it’s only 12.8mm at its thinnest point. That's not a ring; it’s kind of a wave with more or less surface area as it rotates, not to mention the varied sizes of the holes. I think you’ll be fine. I’m not sure what the performance will feel like. Could feel pulsating. Don’t know, and not speaking from experience here.

Good luck.

Well I described (and showed) exactly that, that the contact area is 3.7mm less than the pad's area at the lowest point, but it then proceeds to fully cover the pad as seen in my last picture

So it's neither fully covering, nor constantly lacking contact. More like alternating between a 12.7mm and 15.7mm contact area as the wheel turns.

The more I think about it, and since according to Magura these rotors are designed to work with both 2-piston and 4-piston calipers, the contact area they are designed to work with must be sufficient, so there should be no stopping performance concern. The only thing that remains to be seen is whether the extra pad material can result in noise/vibrations. If that's not the case then I can surely live with knowing my pads are a bit taller than the rotor area

In the picture below is the complete set of this very rotor together with Magura pads for 2-piston calipers that is also available.
I pasted the image of my B05S pads to roughly compare shape and size. I can't say those pads seem really "longer" than my B05S that would compensate for the shorter "height"?

 

[Shifty Shane]

Well I described (and showed) exactly that, that the contact area is 3.7mm less than the pad's area at the lowest point, but it then proceeds to fully cover the pad as seen in my last picture

So it's neither fully covering, nor constantly lacking contact. More like alternating between a 12.7mm and 15.7mm contact area as the wheel turns.

The more I think about it, and since according to Magura these rotors are designed to work with both 2-piston and 4-piston calipers, the contact area they are designed to work with must be sufficient, so there should be no stopping performance concern. The only thing that remains to be seen is whether the extra pad material can result in noise/vibrations. If that's not the case then I can surely live with knowing my pads are a bit taller than the rotor area

In the picture below is the complete set of this very rotor together with Magura pads for 2-piston calipers that is also available.
I pasted the image of my B05S pads to roughly compare shape and size. I can't say those pads seem really "longer" than my B05S that would compensate for the shorter "height"?

View attachment 198079

If you check Maguras website regarding their MT 2 piston calipers, they use the 7P brake pads, which are considered narrow type pads, they are not the same as your Shimano B05S brake pads that fit your BR-MT410 calipers.
I wish these manufacturers' websites would list more dimensions than simply the rotors' outer diameter and thickness.
Hopetech .com lists multiple dimensions which helps identify compatibility with varying calipers and pads.
You can get the Tektro 203mm TR-52 rotors on amazon for $32/each, I can confirm that the outer contact area is 17mm and they are definitely compatible with 2 piston caliper wide style brake pads. I just installed mine, will bed them in tomorrow.

 

[Ringo9]

If you check Maguras website regarding their MT 2 piston calipers, they use the 7P brake pads, which are considered narrow type pads, they are not the same as your Shimano B05S brake pads that fit your BR-MT410 calipers.
I wish these manufacturers' websites would list more dimensions than simply the rotors' outer diameter and thickness.
Hopetech .com lists multiple dimensions which helps identify compatibility with varying calipers and pads.
You can get the Tektro 203mm TR-52 rotors on amazon for $32/each, I can confirm that the outer contact area is 17mm and they are definitely compatible with 2 piston caliper wide style brake pads. I just installed mine, will bed them in tomorrow.

Yeah that would be one way to go for sure. I just don't find the Tektros as readily available around here, and my impatience is kicking in

I also would love to know if anyone has tried that combo before and if it's just Shimano's BS or it really causes an issue...

 

[Gionnirocket]

One thought. . .
If you look at the outer most edge of the rotor you see it dips in reducing the contact area just about at the widest part. Perhaps the same is happening on the inner edge purposely. This may be for cooling and to shed dust build_up
That said my Tektro and Rohloff rotors don't have this reduction in contact area on the inner, and only on the outer circumference of the contact area.. so wtf do I know
I don't know if you're going to get a definitive answer here as the combo in question might not be the most popular out there.
Sometimes we don't have choices with what hardware our bikes come with but this is the main reason I hate proprietary anything and prefer to choose mainstream/middle of the road hardware. Your options/availability are greatly increased.