Notices
991 2012-2019
Sponsored by:
Sponsored by:

991 to 911S Rotor Diameter.

Thread Tools
 
Search this Thread
 
Old Dec 23, 2018 | 11:46 PM
  #16  
PCA1983's Avatar
PCA1983
Rennlist Member
10 Year Member
 
Joined: Apr 2014
Posts: 3,051
Likes: 478
From: Orlando burbs
Default

Originally Posted by Jaws1
991.2 (991.1 in parentheses)
Carrera F: Ø 330 x 34 mm (Ø 330 x 28 mm)
Carrera R: Ø 330 x 34 mm (Ø 330 x 28 mm)
Carrera S F: Ø 350 x 34 mm (Ø 330 x 34 mm)
Carrera S R: Ø 330 x 34 mm (Ø 330 x 28 mm)
OK. My memory was off, on the rotor thicknesses. And my recollection was the 991.2 S was 350 mm Dia versus the 991.1 S at 340 mm dia.
I didn't realize the 991.1 S and Base both have the same 330 mm front rotor 330 mm diameter.*

And the GTS rotors are the same as the S, for both 991.1 and 991.2, right?*

But its the rear 991.1 S rotor that is 6 mm thinner than the rear 991.2 S rotor.*

And in 991.1 Base, both the front and rear rotors are 6 mm thinner than the 991.2 Base and T

Just try to get them straight in my head, for comparison. Porsche endowed the 991.2 with bigger brakes, to deal with the big step up in Hp and in Torque. For most US roads & tracks, the increase in Torque is a bigger factor than Hp for brake size.* The greater grunt of the 991.2s enables them to reach substantially higher speeds between corners.* Approaching top speeds on rural Autobahns, Hp dominates. But for most of us driving on our roads and short tracks, it's the Torque/acceleration that is so dominant.*
Thanks!*
*
Reply
Old Mar 10, 2021 | 06:27 PM
  #17  
Keadog's Avatar
Keadog
Rennlist Member
15 Year Member
 
Joined: Dec 2009
Posts: 7,802
Likes: 1,728
Default

Digging up this old thread, I'm still confused. I had my car in for the latch recall today and talked with the service managers about this in my 991.2 C4. Their computer shows a different part number for rear calipers between the base and S, but this thread makes me think it might just specify a different color (red or black)?

The 2018 problem with pad selection for the base brakes doesn't seem to have changed, but if the rear calipers are the same other than color, how do larger pads from the S fit into the base calipers?
I will need new pads sometime in the next year and would like to try something other than OEM, but the choices seem nil. I wouldn't mind the Suncoast front S upgrade but that would entail getting those calipers repainted black. And still don't know what (if any) other pads will fit the rear.

Very puzzling to this amateur. Is there something simpler that I'm missing?
Reply
Old Mar 10, 2021 | 06:43 PM
  #18  
rnl's Avatar
rnl
Three Wheelin'
10 Year Member
 
Joined: May 2012
Posts: 1,343
Likes: 546
From: Pennsylvania
Default

do you need 20 inch wheels ?
Reply
Old Mar 10, 2021 | 08:58 PM
  #19  
ClassJ's Avatar
ClassJ
Rennlist Member
20 Year Member
 
Joined: Aug 2002
Posts: 1,143
Likes: 306
From: Northern NJ
Default

Originally Posted by Keadog
Digging up this old thread, I'm still confused. I had my car in for the latch recall today and talked with the service managers about this in my 991.2 C4. Their computer shows a different part number for rear calipers between the base and S, but this thread makes me think it might just specify a different color (red or black)?

The 2018 problem with pad selection for the base brakes doesn't seem to have changed, but if the rear calipers are the same other than color, how do larger pads from the S fit into the base calipers?
I will need new pads sometime in the next year and would like to try something other than OEM, but the choices seem nil. I wouldn't mind the Suncoast front S upgrade but that would entail getting those calipers repainted black. And still don't know what (if any) other pads will fit the rear.

Very puzzling to this amateur. Is there something simpler that I'm missing?
According to the PET, rear rotors, pads, and calipers are different on the 991.2 base vs S. I believe the rotors are the same diameter and thickness but the pad contact area is greater. 99135240301 is base left rotor. 99135240302 is left S rotor.

I agree there is some confusion on pads. There are two different pad part numbers. 99135293902 is listed as the proper pad for the base only.

Then, right below that 99135294902 is listed for the S and Base. I believe this to be in error unless at some point a change was made.

Someone else posted the below in the past.

Can someone with an S measure the rotor pad contact width on their car?


[img]blob:https://rennlist.com/d7bb6dd7-ed97-440a-8a35-b4cda46a7d43[/img]

Reply
Old Mar 10, 2021 | 09:59 PM
  #20  
Wujohn's Avatar
Wujohn
Burning Brakes
5 Year Member
 
Joined: Aug 2018
Posts: 1,234
Likes: 431
From: San Diego
Default

Originally Posted by ClassJ
According to the PET, rear rotors, pads, and calipers are different on the 991.2 base vs S. I believe the rotors are the same diameter and thickness but the pad contact area is greater. 99135240301 is base left rotor. 99135240302 is left S rotor.

I agree there is some confusion on pads. There are two different pad part numbers. 99135293902 is listed as the proper pad for the base only.

Then, right below that 99135294902 is listed for the S and Base. I believe this to be in error unless at some point a change was made.

Someone else posted the below in the past.

Can someone with an S measure the rotor pad contact width on their car?


[img]blob:https://rennlist.com/d7bb6dd7-ed97-440a-8a35-b4cda46a7d43[/img]
I recently bought pads for a 991.2 S from Sunset Porsche and they told me that the rear pads were the same (I have a base .2). The part I received was in fact exactly the same as the base pads I had. I suppose they could have mistakenly send me a base pad but it is my understanding that they are exactly the same. Note that this has always confused me too...

https://www.sunsetporscheparts.com/oem-parts/porsche-brake-pads-99135294902

Last edited by Wujohn; Mar 10, 2021 at 10:16 PM. Reason: updated link
Reply
Old Mar 10, 2021 | 10:05 PM
  #21  
ClassJ's Avatar
ClassJ
Rennlist Member
20 Year Member
 
Joined: Aug 2002
Posts: 1,143
Likes: 306
From: Northern NJ
Default

Originally Posted by Wujohn
I recently bought pads for a 991.2 S from Sunset Porsche and they told me that the rear pads were the same (I have a base .2). The part I received was in fact exactly the same. as the base pads I had. I suppose they could have mistakenly send me a base pad but it is my understanding that they are exactly the same. Note that this has always confused me too...

https://www.sunsetporscheparts.com/o...et-99135194702
It could be a compound difference I suppose but even then why are there two rotor part numbers base vs S?

The PET could certainly be wrong. Suncoast had told me a few years ago that the back was identical other than caliper color between S and Base. I discounted this given the PET at the time but I also did not pull the trigger on the swap yet.


Reply
Old Mar 10, 2021 | 10:37 PM
  #22  
Wujohn's Avatar
Wujohn
Burning Brakes
5 Year Member
 
Joined: Aug 2018
Posts: 1,234
Likes: 431
From: San Diego
Default

Originally Posted by ClassJ
It could be a compound difference I suppose but even then why are there two rotor part numbers base vs S?

The PET could certainly be wrong. Suncoast had told me a few years ago that the back was identical other than caliper color between S and Base. I discounted this given the PET at the time but I also did not pull the trigger on the swap yet.
My guess is the PET was wrong given my recent experience and feedback from two reputable dealers/suppliers. I've been looking for used S front calipers for some time but they are not that expensive new. I may eventually do this swap and then decide if I paint the rears red or the new fronts black. I already have 350mm rotors so a pretty easy transition.
Reply
Old Mar 10, 2021 | 11:39 PM
  #23  
ClassJ's Avatar
ClassJ
Rennlist Member
20 Year Member
 
Joined: Aug 2002
Posts: 1,143
Likes: 306
From: Northern NJ
Default

Originally Posted by Wujohn
My guess is the PET was wrong given my recent experience and feedback from two reputable dealers/suppliers. I've been looking for used S front calipers for some time but they are not that expensive new. I may eventually do this swap and then decide if I paint the rears red or the new fronts black. I already have 350mm rotors so a pretty easy transition.
I tend to agree at the moment based on aftermarket parts listings. A dealer or someone with an active PET can answer the question for sure.
Reply
Rennlist Stories

The Best Porsche Posts for Porsche Enthusiasts

story-0

10 Best Non-Flat Six Porsches You Can Buy For Under $100K

 Joe Kucinski
story-1

Porsche's Top 5 Most Questionable Naming Decisions

 Verdad Gallardo
story-2

Pogea Racing's 964 Porsche 911 Reimagination Stands Out in a Crowded Field

 Verdad Gallardo
story-3

6 Convertible Top MYTHS Most People Don't Understand!

 Michael S. Palmer
story-4

2026 Porsche 911 Club Coupe is Spectacular, And Everything Wrong with the Porsche Market

 Joe Kucinski
story-5

Talos Takes Your 991 Porsche 911 GT3 to the Next Level for a Cool $1.13 Million

 Verdad Gallardo
story-6

9 Vehicles Porsche Helped Engineer that Aren't Porsches

 Verdad Gallardo
story-7

9 Features and Characteristics That Only Porsche People Understand

 Verdad Gallardo
story-8

I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way

 Joe Kucinski
story-9

10 Most Unnecessary Porsches Ever Built (And Why We Love Them)

 Verdad Gallardo
Old Mar 11, 2021 | 06:37 AM
  #24  
Keadog's Avatar
Keadog
Rennlist Member
15 Year Member
 
Joined: Dec 2009
Posts: 7,802
Likes: 1,728
Default

I also believe my dealer to be reputable; there was some confusion with them about this. I don’t need new brakes or pads but want to be prepared when the time comes.
Thanks for the input.
Does anyone have a list of what pads will fit the base brakes (Endless, Pagid, EBC, etc.)? If any? With apparently so little choice, it makes Suncoast’s $2k for the entire front S set up seem not so bad. Except for the fact I don’t want red calipers and that leads to a separate issue of safely painting the new calipers.
Reply
Old Mar 11, 2021 | 01:19 PM
  #25  
Wujohn's Avatar
Wujohn
Burning Brakes
5 Year Member
 
Joined: Aug 2018
Posts: 1,234
Likes: 431
From: San Diego
Default

Originally Posted by Keadog
I also believe my dealer to be reputable; there was some confusion with them about this. I don’t need new brakes or pads but want to be prepared when the time comes.
Thanks for the input.
Does anyone have a list of what pads will fit the base brakes (Endless, Pagid, EBC, etc.)? If any? With apparently so little choice, it makes Suncoast’s $2k for the entire front S set up seem not so bad. Except for the fact I don’t want red calipers and that leads to a separate issue of safely painting the new calipers.
Endless - these are track pads and noisy relative to stock pads. They do make more streetable pads if you don't track your car.
EIP218ME20
EIP193ME20

Below are measurements for 991.2 pads - you can use this when talking to a manufacturer about what will fit. Not every pad will be exactly the same size - a few mm off here or there will be fine.


Last edited by Wujohn; Mar 11, 2021 at 01:20 PM.
Reply
Old Mar 11, 2021 | 04:57 PM
  #26  
Keadog's Avatar
Keadog
Rennlist Member
15 Year Member
 
Joined: Dec 2009
Posts: 7,802
Likes: 1,728
Default

Originally Posted by Wujohn
Endless - these are track pads and noisy relative to stock pads. They do make more streetable pads if you don't track your car.
EIP218ME20
EIP193ME20

Below are measurements for 991.2 pads - you can use this when talking to a manufacturer about what will fit. Not every pad will be exactly the same size - a few mm off here or there will be fine.

This is very helpful. Thanks! I started out looking for a pad that would create less dust and has been far more difficult to get good information on than I would have ever guessed.
The brakes work better than I can drive already, but I'm running out of things to do on the car.

It's a little off topic, but I'm going to be flushing the brake fluid early next month when I put on my summer tires. Is there any reason no to use Endless (other than cost) on this 99.99% street car? I like the idea of going to a clear fluid to see all the original fluid has been flushed out. I read somewhere it may interfere with ABS on street cars but i can't remember where. I guess other choices are Motul .4 or 5.1 or Castrol, but I am unlikely to ever boil my brake fluid. I may do a DE day or two at Mid Ohio if things ever reopen "normally" though. Just for fun.
Reply
Old Mar 11, 2021 | 05:22 PM
  #27  
Wujohn's Avatar
Wujohn
Burning Brakes
5 Year Member
 
Joined: Aug 2018
Posts: 1,234
Likes: 431
From: San Diego
Default

Originally Posted by Keadog
This is very helpful. Thanks! I started out looking for a pad that would create less dust and has been far more difficult to get good information on than I would have ever guessed.
The brakes work better than I can drive already, but I'm running out of things to do on the car.

It's a little off topic, but I'm going to be flushing the brake fluid early next month when I put on my summer tires. Is there any reason no to use Endless (other than cost) on this 99.99% street car? I like the idea of going to a clear fluid to see all the original fluid has been flushed out. I read somewhere it may interfere with ABS on street cars but i can't remember where. I guess other choices are Motul .4 or 5.1 or Castrol, but I am unlikely to ever boil my brake fluid. I may do a DE day or two at Mid Ohio if things ever reopen "normally" though. Just for fun.
MX72+ pads are supposed to be great performers for dual duty purposes. Saw this in a thread today and have also heard from others that they like them, so that is probably a good but more expensive than stock option. I don't know a lot about endless fluid but doubt you need more than motul rbf 660, which I believe is cheaper.
Reply
Old Mar 11, 2021 | 07:48 PM
  #28  
Keadog's Avatar
Keadog
Rennlist Member
15 Year Member
 
Joined: Dec 2009
Posts: 7,802
Likes: 1,728
Default

Originally Posted by Wujohn
MX72+ pads are supposed to be great performers for dual duty purposes. Saw this in a thread today and have also heard from others that they like them, so that is probably a good but more expensive than stock option. I don't know a lot about endless fluid but doubt you need more than motul rbf 660, which I believe is cheaper.
Thanks and yes, I agree I don’t need “racing” brake fluid for my driving habits. But, as I understand it, Endless is now the only non-yellow (clear) brake fluid available since the blue/yellow color alternates were outlawed by our betters. I would like visual confirmation that all the old fluid is out of the system if possible.
I’ll look into those pads again but I don’t think they make front pads that will fit the front (base) calipers. I could be wrong.
Reply
Old Mar 11, 2021 | 09:27 PM
  #29  
Wujohn's Avatar
Wujohn
Burning Brakes
5 Year Member
 
Joined: Aug 2018
Posts: 1,234
Likes: 431
From: San Diego
Default

Originally Posted by Keadog
Thanks and yes, I agree I don’t need “racing” brake fluid for my driving habits. But, as I understand it, Endless is now the only non-yellow (clear) brake fluid available since the blue/yellow color alternates were outlawed by our betters. I would like visual confirmation that all the old fluid is out of the system if possible.
I’ll look into those pads again but I don’t think they make front pads that will fit the front (base) calipers. I could be wrong.
Call up Endless - they have an office in SoCal. See link - looks like they make them in most compounds but would need to verify if that also includes the MX72+

https://www.northstarmotorsports.com...roductID/10229

Endless
https://endless-sport.global/us/distributor

Last edited by Wujohn; Mar 11, 2021 at 09:32 PM.
Reply
Old Mar 12, 2021 | 09:32 AM
  #30  
Keadog's Avatar
Keadog
Rennlist Member
15 Year Member
 
Joined: Dec 2009
Posts: 7,802
Likes: 1,728
Default

Originally Posted by Wujohn
Call up Endless - they have an office in SoCal. See link - looks like they make them in most compounds but would need to verify if that also includes the MX72+

https://www.northstarmotorsports.com...roductID/10229

Endless
https://endless-sport.global/us/distributor
Thanks, will do. I had emailed them but their reply made it seem like a "no".
Reply




All times are GMT -3. The time now is 04:55 PM.

story-0
10 Best Non-Flat Six Porsches You Can Buy For Under $100K

Slideshow: If you have $100K to spend on a Porsche but want something a little different, these are the 10 best non-flat six Porsches you can buy.

By Joe Kucinski | 2026-05-28 15:36:11


VIEW MORE
story-1
Porsche's Top 5 Most Questionable Naming Decisions

Slideshow: For a company obsessed with engineering precision, Porsche has occasionally named its cars in ways that left even loyal enthusiasts scratching their heads.

By Verdad Gallardo | 2026-05-27 18:43:48


VIEW MORE
story-2
Pogea Racing's 964 Porsche 911 Reimagination Stands Out in a Crowded Field

Slideshow: Pogea Racing's latest Porsche 964 project blends carbon-fiber construction, modern chassis upgrades, and up to 500 horsepower while keeping the air-cooled 911 experience firmly analog.

By Verdad Gallardo | 2026-05-23 10:34:27


VIEW MORE
story-3
6 Convertible Top MYTHS Most People Don't Understand!

Slideshow: dispelling common convertible top myths

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-4
2026 Porsche 911 Club Coupe is Spectacular, And Everything Wrong with the Porsche Market

Slideshow: The 2026 Porsche 911 Club Coupe is being resold $150K above sticker and that is a real problem.

By Joe Kucinski | 2026-05-21 11:52:54


VIEW MORE
story-5
Talos Takes Your 991 Porsche 911 GT3 to the Next Level for a Cool $1.13 Million

Slideshow: Talos Vehicles has transformed the Porsche 911 GT3 RS into a carbon-bodied, race-inspired machine that costs well over $1 million before the donor car is even included.

By Verdad Gallardo | 2026-05-19 13:39:04


VIEW MORE
story-6
9 Vehicles Porsche Helped Engineer that Aren't Porsches

Slideshow: Long before engineering consulting became trendy, Porsche was quietly helping other automakers build everything from supercars to economy hatchbacks.

By Verdad Gallardo | 2026-05-15 12:44:44


VIEW MORE
story-7
9 Features and Characteristics That Only Porsche People Understand

Slideshow: Some brands build cars. Porsche builds traditions, obsessions, and a few habits that stopped making sense decades ago but somehow became part of the charm.

By Verdad Gallardo | 2026-05-13 18:46:13


VIEW MORE
story-8
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way

Slideshow: Six years and 500 Rennlist articles later, these are the biggest changes at Porsche.

By Joe Kucinski | 2026-05-11 09:52:55


VIEW MORE
story-9
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)

Slideshow: Some Porsches exist for very specific reasons-others feel like they were built just to see if anyone would notice.

By Verdad Gallardo | 2026-05-06 18:00:32


VIEW MORE