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Rotor material?



 
 
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  #1  
Old October 5th 17, 08:34 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 4,453
Default Rotor material?

Some rotors are sold for "resin pads only", others do not list
restrictions. What is the difference in materials?

I am using ceramic based pads not normally sold at the LBS, supposedly
similar to what motorcycles have. Because they give me best results.

Other questions while at it:

My rotors are formally 7" and 6". Can I use 180mm and 160mm instead? The
7" one on my MTB actually measures about 185mm. I'd hate to have to
grind down the spacer but might have to because 7" is more rare.

Does anyone know what the raw rotors foer custom-laser deals are called?
Couldn't find any on EBay. Ideally I'd want rotors that are solid like
on motor vehicles, for better heat tolerance. Weight doesn't matter.

--
Regards, Joerg

http://www.analogconsultants.com/
Ads
  #2  
Old October 5th 17, 08:39 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 4,453
Default Rotor material?

On 2017-10-05 12:34, Joerg wrote:
Some rotors are sold for "resin pads only", others do not list
restrictions. What is the difference in materials?

I am using ceramic based pads not normally sold at the LBS, supposedly
similar to what motorcycles have. Because they give me best results.

Other questions while at it:

My rotors are formally 7" and 6". Can I use 180mm and 160mm instead? The
7" one on my MTB actually measures about 185mm. I'd hate to have to
grind down the spacer but might have to because 7" is more rare.

Does anyone know what the raw rotors foer custom-laser deals are called?
Couldn't find any on EBay. Ideally I'd want rotors that are solid like
on motor vehicles, for better heat tolerance. Weight doesn't matter.


Add-on: I am also looking for at least 2.2mm thickness like the
originals from Promax. The newer ones from Promax only have 2mm and also
a weird wavy design:

http://i.ebayimg.com/images/g/qjAAAO...rj/s-l1600.jpg

--
Regards, Joerg

http://www.analogconsultants.com/
  #3  
Old October 5th 17, 11:41 PM posted to rec.bicycles.tech
JBeattie
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Posts: 2,696
Default Rotor material?

On Thursday, October 5, 2017 at 12:39:02 PM UTC-7, Joerg wrote:
On 2017-10-05 12:34, Joerg wrote:
Some rotors are sold for "resin pads only", others do not list
restrictions. What is the difference in materials?

I am using ceramic based pads not normally sold at the LBS, supposedly
similar to what motorcycles have. Because they give me best results.

Other questions while at it:

My rotors are formally 7" and 6". Can I use 180mm and 160mm instead? The
7" one on my MTB actually measures about 185mm. I'd hate to have to
grind down the spacer but might have to because 7" is more rare.

Does anyone know what the raw rotors foer custom-laser deals are called?
Couldn't find any on EBay. Ideally I'd want rotors that are solid like
on motor vehicles, for better heat tolerance. Weight doesn't matter.


Add-on: I am also looking for at least 2.2mm thickness like the
originals from Promax. The newer ones from Promax only have 2mm and also
a weird wavy design:

http://i.ebayimg.com/images/g/qjAAAO...rj/s-l1600.jpg

--
Regards, Joerg

http://www.analogconsultants.com/


Hayes makes the 5-7" rotors. https://www.universalcycles.com/shop...ls.php?id=5018 You could always go with a bigger metric size and add spacers rather than going smaller and grinding down your current bracket. You would have to get longer bolts probably. This would also accommodate your gnarly riding style and need for maximum braking power. Go big or go home!

I use sintered metalic pads because they last a long time and work well in wet conditions. I am not familiar with the ceramic/metal pads except that I have seen them on the rack.

All one piece rotors I know of are SS, although you can buy CF rotors. Magura (and I think Avid) makes thick rotors (2mm) that are supposed to be good at shedding heat, but I don't know of anyone who makes them thicker than that.
You'll have to do some detective work.

-- Jay Beattie.
  #4  
Old October 6th 17, 12:38 AM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 4,453
Default Rotor material?

On 2017-10-05 15:41, jbeattie wrote:
On Thursday, October 5, 2017 at 12:39:02 PM UTC-7, Joerg wrote:
On 2017-10-05 12:34, Joerg wrote:
Some rotors are sold for "resin pads only", others do not list
restrictions. What is the difference in materials?

I am using ceramic based pads not normally sold at the LBS,
supposedly similar to what motorcycles have. Because they give me
best results.

Other questions while at it:

My rotors are formally 7" and 6". Can I use 180mm and 160mm
instead? The 7" one on my MTB actually measures about 185mm. I'd
hate to have to grind down the spacer but might have to because
7" is more rare.

Does anyone know what the raw rotors foer custom-laser deals are
called? Couldn't find any on EBay. Ideally I'd want rotors that
are solid like on motor vehicles, for better heat tolerance.
Weight doesn't matter.


Add-on: I am also looking for at least 2.2mm thickness like the
originals from Promax. The newer ones from Promax only have 2mm and
also a weird wavy design:

http://i.ebayimg.com/images/g/qjAAAO...rj/s-l1600.jpg

-- Regards, Joerg

http://www.analogconsultants.com/


Hayes makes the 5-7" rotors.
https://www.universalcycles.com/shop...ls.php?id=5018



The data on those is a bit unreliable. For example, here the same P/N
98-17551 rotor is listed as 160mm which isn't 6":

https://www.worldwidecyclery.com/col...-with-hardware

I believe Hayes rotors are also only 1.9mm thick and I'd be through that
in a jiffy.

It was similar when I bought a BB for my road bike. Most US dealers
listed it as JIS taper which is what I needed and most UK dealers listed
the same P/N as non-JIS. Shimano had no "Contact us" on their home page.
Luckily it ended up being JIS.


You could always go with a bigger metric size and add spacers rather
than going smaller and grinding down your current bracket. You would
have to get longer bolts probably. This would also accommodate your
gnarly riding style and need for maximum braking power. Go big or go
home!


Indeed. I am thinking about upping the front to 203mm which equates to a
true 8". With 7" you always have the discrepancy and a standard 180mm
rotor is 5mm too small so I'd have no choice but to grind off.

My style isn't so gnarly but we have long steep descents here. A friend
who rode ahead of me lost his front brake before the last sharp turn
once. That was a real white-knuckle situation. It was weird, he had 8"
versus my 7" and weighs less, same route and speed.


I use sintered metalic pads because they last a long time and work
well in wet conditions. I am not familiar with the ceramic/metal pads
except that I have seen them on the rack.


The ceramic-based ones last much longer for me. But who knows, maybe the
sintered ones I used before didn't like wet rides too much. The only
downside is a sandpaper sound when they are applied for a long descent
and become hot. Goes away once cooled off.


All one piece rotors I know of are SS, although you can buy CF
rotors.



There must be different steel in Shimano SM-RT56 versus SM-RT66 rotors
because they do not allow the RT56 to be operated with anything other
than resin pads.


... Magura (and I think Avid) makes thick rotors (2mm) that are
supposed to be good at shedding heat, but I don't know of anyone who
makes them thicker than that. You'll have to do some detective work.


It'll be tough because the thickness is almost never listed. There used
to be custom shops where you could have a rotor with a laser-cut
"Beattie Racing" made. One of them had 3mm thick versions and I could
ask them for raw rotors (full discs, no gaps, like on many motor
vehicles). However, seems they are gone.

I wish the original thick Promax rotors were still available. They are
really good but the micrometer shows them down to 1.75mm in front and
1.65mm in back. So they need to be replaced soon.

--
Regards, Joerg

http://www.analogconsultants.com/
  #5  
Old October 6th 17, 02:37 AM posted to rec.bicycles.tech
James[_8_]
external usenet poster
 
Posts: 5,643
Default Rotor material?

On 06/10/17 09:41, jbeattie wrote:


All one piece rotors I know of are SS, although you can buy CF
rotors. Magura (and I think Avid) makes thick rotors (2mm) that are
supposed to be good at shedding heat, but I don't know of anyone who
makes them thicker than that. You'll have to do some detective work.



I wouldn't have guessed that slightly thicker rotors would be
appreciably better at "shedding heat".

--
JS
  #6  
Old October 6th 17, 03:14 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 5,281
Default Rotor material?

On 10/5/2017 9:37 PM, James wrote:
On 06/10/17 09:41, jbeattie wrote:


All one piece rotors I know of are SS, although you can buy CF
rotors.* Magura (and I think Avid) makes thick rotors (2mm) that are
supposed to be good at shedding heat, but I don't know of anyone who
makes them thicker than that. You'll have to do some detective work.



I wouldn't have guessed that slightly thicker rotors would be
appreciably better at "shedding heat".


Agreed. Initial temperature rise might be slightly less rapid due to the
larger mass. Once steady state was reached, as on a long descent, I
doubt it would make any difference at all. Surface area is what matters
then, and the difference in surface area would be negligible.

--
- Frank Krygowski
  #7  
Old October 6th 17, 04:10 AM posted to rec.bicycles.tech
Sir Ridesalot
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Posts: 3,571
Default Rotor material?

On Thursday, October 5, 2017 at 7:38:42 PM UTC-4, Joerg wrote:
On 2017-10-05 15:41, jbeattie wrote:
On Thursday, October 5, 2017 at 12:39:02 PM UTC-7, Joerg wrote:
On 2017-10-05 12:34, Joerg wrote:
Some rotors are sold for "resin pads only", others do not list
restrictions. What is the difference in materials?

I am using ceramic based pads not normally sold at the LBS,
supposedly similar to what motorcycles have. Because they give me
best results.

Other questions while at it:

My rotors are formally 7" and 6". Can I use 180mm and 160mm
instead? The 7" one on my MTB actually measures about 185mm. I'd
hate to have to grind down the spacer but might have to because
7" is more rare.

Does anyone know what the raw rotors foer custom-laser deals are
called? Couldn't find any on EBay. Ideally I'd want rotors that
are solid like on motor vehicles, for better heat tolerance.
Weight doesn't matter.


Add-on: I am also looking for at least 2.2mm thickness like the
originals from Promax. The newer ones from Promax only have 2mm and
also a weird wavy design:

http://i.ebayimg.com/images/g/qjAAAO...rj/s-l1600.jpg

-- Regards, Joerg

http://www.analogconsultants.com/


Hayes makes the 5-7" rotors.
https://www.universalcycles.com/shop...ls.php?id=5018



The data on those is a bit unreliable. For example, here the same P/N
98-17551 rotor is listed as 160mm which isn't 6":


160mm is 6.299212598425197. Does that extra .2992125... make that much of a difference?

Cheers
  #8  
Old October 6th 17, 07:20 AM posted to rec.bicycles.tech
John B.[_3_]
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Posts: 3,380
Default Rotor material?

On Thu, 5 Oct 2017 20:10:57 -0700 (PDT), Sir Ridesalot
wrote:

On Thursday, October 5, 2017 at 7:38:42 PM UTC-4, Joerg wrote:
On 2017-10-05 15:41, jbeattie wrote:
On Thursday, October 5, 2017 at 12:39:02 PM UTC-7, Joerg wrote:
On 2017-10-05 12:34, Joerg wrote:
Some rotors are sold for "resin pads only", others do not list
restrictions. What is the difference in materials?

I am using ceramic based pads not normally sold at the LBS,
supposedly similar to what motorcycles have. Because they give me
best results.

Other questions while at it:

My rotors are formally 7" and 6". Can I use 180mm and 160mm
instead? The 7" one on my MTB actually measures about 185mm. I'd
hate to have to grind down the spacer but might have to because
7" is more rare.

Does anyone know what the raw rotors foer custom-laser deals are
called? Couldn't find any on EBay. Ideally I'd want rotors that
are solid like on motor vehicles, for better heat tolerance.
Weight doesn't matter.


Add-on: I am also looking for at least 2.2mm thickness like the
originals from Promax. The newer ones from Promax only have 2mm and
also a weird wavy design:

http://i.ebayimg.com/images/g/qjAAAO...rj/s-l1600.jpg

-- Regards, Joerg

http://www.analogconsultants.com/

Hayes makes the 5-7" rotors.
https://www.universalcycles.com/shop...ls.php?id=5018



The data on those is a bit unreliable. For example, here the same P/N
98-17551 rotor is listed as 160mm which isn't 6":


160mm is 6.299212598425197. Does that extra .2992125... make that much of a difference?

Cheers


It might effect the location of the brake on the fork as it would mean
that the 160mm brake was about .149" larger radius but I do see brake
rotors listed as "6 inch (160mm)" or "7inch (170mm)" which sort of
makes one wonder how critical the measurement is.
--
Cheers,

John B.

  #9  
Old October 6th 17, 02:00 PM posted to rec.bicycles.tech
AMuzi
external usenet poster
 
Posts: 8,936
Default Rotor material?

On 10/5/2017 10:10 PM, Sir Ridesalot wrote:
On Thursday, October 5, 2017 at 7:38:42 PM UTC-4, Joerg wrote:
On 2017-10-05 15:41, jbeattie wrote:
On Thursday, October 5, 2017 at 12:39:02 PM UTC-7, Joerg wrote:
On 2017-10-05 12:34, Joerg wrote:
Some rotors are sold for "resin pads only", others do not list
restrictions. What is the difference in materials?

I am using ceramic based pads not normally sold at the LBS,
supposedly similar to what motorcycles have. Because they give me
best results.

Other questions while at it:

My rotors are formally 7" and 6". Can I use 180mm and 160mm
instead? The 7" one on my MTB actually measures about 185mm. I'd
hate to have to grind down the spacer but might have to because
7" is more rare.

Does anyone know what the raw rotors foer custom-laser deals are
called? Couldn't find any on EBay. Ideally I'd want rotors that
are solid like on motor vehicles, for better heat tolerance.
Weight doesn't matter.


Add-on: I am also looking for at least 2.2mm thickness like the
originals from Promax. The newer ones from Promax only have 2mm and
also a weird wavy design:

http://i.ebayimg.com/images/g/qjAAAO...rj/s-l1600.jpg

-- Regards, Joerg

http://www.analogconsultants.com/

Hayes makes the 5-7" rotors.
https://www.universalcycles.com/shop...ls.php?id=5018



The data on those is a bit unreliable. For example, here the same P/N
98-17551 rotor is listed as 160mm which isn't 6":


160mm is 6.299212598425197. Does that extra .2992125... make that much of a difference?

Cheers


A 160mm rotor is 160mm edge to edge.

It's 'about six inches' in the same way that a 700-25 is
about 27". A 27x1-1/4 is about 27-1/2 inches but you can't
call it that because 584mm 26-inch systems, which are
smaller than 630mm 27", already own that moniker.

Yes, it's nonsensical. Zen is acceptance. Carry on.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #10  
Old October 6th 17, 02:51 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 3,183
Default Rotor material?

On Thursday, October 5, 2017 at 6:37:10 PM UTC-7, James wrote:
On 06/10/17 09:41, jbeattie wrote:


All one piece rotors I know of are SS, although you can buy CF
rotors. Magura (and I think Avid) makes thick rotors (2mm) that are
supposed to be good at shedding heat, but I don't know of anyone who
makes them thicker than that. You'll have to do some detective work.



I wouldn't have guessed that slightly thicker rotors would be
appreciably better at "shedding heat".


On MTB's on difficult descents the rotors are almost red-hot. Since I've never seen rims that hot I can only assume that the disks allow you to hang it out a lot further.
 




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