Big Brake Rotor Question
Thread Starter
Joined: Nov 2009
Posts: 6,984
Likes: 18
From: Marysville WA
Big Brake Rotor Question
so here is the Skinny, GTS big blacks, Adapters from 928Specialty.
i got a used rotor to test fit everything. i cant remeber what its off and the only numbers i can find on it are L1520 (OZ) 13177 . but any way, looks like it will almost work. outer pad has a little to much room, rotor surface seams a little small for the pad.
rough messurments are 302mm across, and from bottom to top of hat is 72mm
what rotor should work for that?
i got a used rotor to test fit everything. i cant remeber what its off and the only numbers i can find on it are L1520 (OZ) 13177 . but any way, looks like it will almost work. outer pad has a little to much room, rotor surface seams a little small for the pad.
rough messurments are 302mm across, and from bottom to top of hat is 72mm
what rotor should work for that?
Rennlist Member
Joined: Dec 2004
Posts: 3,527
Likes: 591
From: West Chester, PA
Looks like it may be an S4 rotor - if indeed you have the GTS calipers. Also, it looks like it is on the wrong side, as the internal vanes are meant to pump air OUT of the caliper, not into it.
Hope you get it straightened out.
Gary Knox
Hope you get it straightened out.
Gary Knox
Rennlist Member
Joined: Feb 2003
Posts: 29,828
Likes: 218
From: saratoga, ca
the 993tt rotors are the same diameter as GTS, that will solve the problem, if the offset it correct. I thought this kit was to mount S4 calipers to a OB, and then use the 993 rotors for the correct offset. is that what you are doing?
I see you are just using some dummy rotors to see if it all fits. but, it looks like the offset is correct, is it? if so, then the GTS rotors will work. I fogot the offset differences between the S4/GTS vs the 993TT, but the net result is the rotor is too close to the tie rod ball joint on the OBs, right?
mk
I see you are just using some dummy rotors to see if it all fits. but, it looks like the offset is correct, is it? if so, then the GTS rotors will work. I fogot the offset differences between the S4/GTS vs the 993TT, but the net result is the rotor is too close to the tie rod ball joint on the OBs, right?
mk
Trending Topics
Thread Starter
Joined: Nov 2009
Posts: 6,984
Likes: 18
From: Marysville WA
thats a good question. i know from mounting the caliper that it can be a little wider of a rotor. i mean that one "fits" but one pad gets to travel way more then the other. any one have pictures of the 993tt rotor mounted?
Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
9 Features and Characteristics That Only Porsche People Understand
Verdad Gallardo
I've Written 500 Rennlist Articles: Here's How Porsche Has Changed Along the Way
Joe Kucinski
10 Most Unnecessary Porsches Ever Built (And Why We Love Them)
Verdad Gallardo
Porsche 911 GT3 S/C vs 718 Spyder RS: 10 Categories, One Winner
Joe Kucinski
This Builder Is Turning Heads With Its Slantnose 911 Creation
Verdad Gallardo
Porsche 911 GT3 Artisan Edition Pays Homage to Japanese Culture
Verdad Gallardo
Porsche Reveals Coupe Variant of the Electric Cayenne With a Fresh Look
Verdad Gallardo
10 Porsche Colors That Have More Personality Than Most People
Verdad Gallardo
Guntherwerks' Final Speedster Creation Is the Ultimate Porsche Restomod
Verdad Gallardo
Rennlist Member
Joined: Feb 2003
Posts: 29,828
Likes: 218
From: saratoga, ca
so,it looks like that migth be a 993, non TT rotor? same offset as the TT rotors?I would think so, if that is so, then when you use the TTs, you will get teh 322mm diameter and the correct offset I would image. cool kit!
Rennlist Member
Joined: Nov 2004
Posts: 5,250
Likes: 1,053
From: DFW Texas
The Big Blacks from the GTS are the same caliper as the Big Reds on the 993TT. The only difference is the Bleed and cross-over tubes are reversed. Thats because on the 928 the caliper is mounted on the back of the rotor and on the 911 it's mounted on the front.
You CANNOT use the 993TT rotor on the 928 assuming the kit you bought is to mount Big Blacks on a 928. The rotor that fits is the 928 GTS or the 965 rotor, P/N 928-351-045-01, LH rotor, solid, 965.351.045.00 rotor, ventilated, LH (cast holes) 322mm, 928-351-046-01, RH rotor, solid 965.351.046.00 rotor, ventilated, RH (cast holes) 322mm.
I converted my 89GT to 993TT calipers and I know the 965 rotors are a perfect fit both in diameter and offset. The rotor must be centered on the caliper, with equal space on both sides, and the rotor must be slightly larger than the pad area. The pictures of the rotor installed is all wrong!
I know nothing about adding these to an older 928 so YMMV.
You CANNOT use the 993TT rotor on the 928 assuming the kit you bought is to mount Big Blacks on a 928. The rotor that fits is the 928 GTS or the 965 rotor, P/N 928-351-045-01, LH rotor, solid, 965.351.045.00 rotor, ventilated, LH (cast holes) 322mm, 928-351-046-01, RH rotor, solid 965.351.046.00 rotor, ventilated, RH (cast holes) 322mm.
I converted my 89GT to 993TT calipers and I know the 965 rotors are a perfect fit both in diameter and offset. The rotor must be centered on the caliper, with equal space on both sides, and the rotor must be slightly larger than the pad area. The pictures of the rotor installed is all wrong!
I know nothing about adding these to an older 928 so YMMV.
Rennlist Member
Joined: Feb 2003
Posts: 29,828
Likes: 218
From: saratoga, ca
Jim, this is a special kit for the older 928s and the GTS or S4 conversion, I think. 
I dont think the GTS or S4 rotors can work, due to the wrong offset that would put the rotor too close to the lower tie rod ball joint. correct?
mk
I dont think the GTS or S4 rotors can work, due to the wrong offset that would put the rotor too close to the lower tie rod ball joint. correct?
mk
The Big Blacks from the GTS are the same caliper as the Big Reds on the 993TT. The only difference is the Bleed and cross-over tubes are reversed. Thats because on the 928 the caliper is mounted on the back of the rotor and on the 911 it's mounted on the front.
You CANNOT use the 993TT rotor on the 928 assuming the kit you bought is to mount Big Blacks on a 928. The rotor that fits is the 928 GTS or the 965 rotor, P/N 928-351-045-01, LH rotor, solid, 965.351.045.00 rotor, ventilated, LH (cast holes) 322mm, 928-351-046-01, RH rotor, solid 965.351.046.00 rotor, ventilated, RH (cast holes) 322mm.
I converted my 89GT to 993TT calipers and I know the 965 rotors are a perfect fit both in diameter and offset. The rotor must be centered on the caliper, with equal space on both sides, and the rotor must be slightly larger than the pad area. The pictures of the rotor installed is all wrong!
I know nothing about adding these to an older 928 so YMMV.
You CANNOT use the 993TT rotor on the 928 assuming the kit you bought is to mount Big Blacks on a 928. The rotor that fits is the 928 GTS or the 965 rotor, P/N 928-351-045-01, LH rotor, solid, 965.351.045.00 rotor, ventilated, LH (cast holes) 322mm, 928-351-046-01, RH rotor, solid 965.351.046.00 rotor, ventilated, RH (cast holes) 322mm.
I converted my 89GT to 993TT calipers and I know the 965 rotors are a perfect fit both in diameter and offset. The rotor must be centered on the caliper, with equal space on both sides, and the rotor must be slightly larger than the pad area. The pictures of the rotor installed is all wrong!
I know nothing about adding these to an older 928 so YMMV.
