Girodisc Rotors: 2 piece vs 1 piece

Hiboost · Oct 5, 2009, 08:33 AM

I have a HPDE coming up next weekend and I'm trying to get a set of the front 2 piece Girodisc rotors lined up for the event. Between the website being down and not getting through on the phone I found out that they sold the last set of Evo X 2 piece front rotors last Thursday.

I currently have the slotted 1 piece rear rotors so I'm considering just getting the 1 piece for the front as well. For those that have bought the 2 piece, are they worth the extra initial expense? At this point I'm already looking at 3 day shipping from WA since it's 5 days via ground from the west coast.

So does anyone have these in stock somewhere closer to the east coast?

Jeffroevoix · Oct 5, 2009, 08:41 AM

Racingbrake make a nice 2 piece set for the X. There are alot of dealers spread around the north east

BlackTrack · Oct 5, 2009, 08:45 AM

I have them and love them. A single set has lasted me more than a year...and I track the car quite a bit. They stay much cooler than a traditional rotor and they're obviously much lighter.

Definitely worth the extra cost up front.

EmeryatSTM · Oct 5, 2009, 08:46 AM

Chris, let me know if we can help. I amy be able to get something for you.

-Em

goofygrin · Oct 5, 2009, 08:54 AM

The vaning is different on the 1 piece vs. 2 piece. This cools the rotor better.

I was struggling with the same decision and between the lower weight and better cooling (which I needed), I decided to spend the money. No fade since. Also, my pads were turning ashen from the heat, and that's stopped (people in lighter cars, on the same pads had the white ash at the same track day). I did change the fluid to endless, removed the dust shields and put porsche air guide on at the same time though...

Hiboost · Oct 5, 2009, 03:51 PM

Looks like the 2 piece front rotors are in high demand lately. According to STM the Racing Brake rotors were 10 weeks out and DBA rotors were 2 weeks out. I'm still working with Girodisc for maybe overnighting a front set from the west coast but that will cost $150+ for shipping.

Even just settling on the 1 piece rotors, turns out they are sold out of those too so I guess I painted myself into a corner.

I suppose I can just get my current rotors lightly turned and hope that the new brake ducts keep everything cool enough. They have a slight uneven stopping feeling pulling up slow to lights but you really can't feel anything in the steering wheel. Hauling down from high speeds they seem fine but we all know that 20 minutes of heavy braking with race pads is a totally different operating condition than anything you can manage on the street (at least safely).

goofygrin · Oct 5, 2009, 03:54 PM

Have you turned the stock rotors yet? I turned mine without any issues. One was so badly out of round it took three cycles to get close. They lasted another 10k miles or so.

If it's just a light pulsing at slow speeds, its likely either mistorqued lugs or pad transfer.

ETA: I just had to shave my DTC30 pads this weekend. They were fine at low temp, but once they heated up, they would "stick" in the channel in the caliper and give me pulsing like a badly warped rotor. Switching pads yielded no shake, so I knew it was the pads. They were marginally wider than the other pads, so a quick zip with the bench grinder and the vibration is gone. I also burned of the little bump on the back side that was causing a low speed squeal with my ti shims. Ahh silent braking

Hiboost · Oct 5, 2009, 06:50 PM

Quote:

Originally Posted by goofygrin

Have you turned the stock rotors yet? I turned mine without any issues. One was so badly out of round it took three cycles to get close. They lasted another 10k miles or so.

If it's just a light pulsing at slow speeds, its likely either mistorqued lugs or pad transfer.

ETA: I just had to shave my DTC30 pads this weekend. They were fine at low temp, but once they heated up, they would "stick" in the channel in the caliper and give me pulsing like a badly warped rotor. Switching pads yielded no shake, so I knew it was the pads. They were marginally wider than the other pads, so a quick zip with the bench grinder and the vibration is gone. I also burned of the little bump on the back side that was causing a low speed squeal with my ti shims. Ahh silent braking

Stock Rotors were replaced by Mitsu in the spring and warped after I failed to properly bed the race pads to the new rotors... Lesson learned! Since then I did a quick resurfacing by hand with sand paper and they were 90% good as new. Likely if I get a fresh cut on them they still have plenty of meat and should hold up ok. That is provided I bed the race pads in properly and don't overcook the brakes.

GSXR · Oct 5, 2009, 10:24 PM

Quote:

Originally Posted by goofygrin

The vaning is different on the 1 piece vs. 2 piece. This cools the rotor better.

I was struggling with the same decision and between the lower weight and better cooling (which I needed), I decided to spend the money. No fade since. Also, my pads were turning ashen from the heat, and that's stopped (people in lighter cars, on the same pads had the white ash at the same track day). I did change the fluid to endless, removed the dust shields and put porsche air guide on at the same time though...

goofygrin, just curious what the porsche air guide is. sorry for the off-topic.

fugiwara · Oct 5, 2009, 10:28 PM

two piece rotor are the way to go for any car, better cooling and less weight

goofygrin · Oct 6, 2009, 08:12 AM

Quote:

Originally Posted by GSXR

goofygrin, just curious what the porsche air guide is. sorry for the off-topic.

They are plastic scoops that mount to the a arm (using the integrated clips and zip ties) that direct air to the calipers. A buddy works at a porsche dealer and gets them for us. About $20/set. Cheaper than the Mitsu ones and about 2x as large.

GSXR · Oct 6, 2009, 10:26 AM

^^ Thanks for thr tip!

flyguycfi · Oct 6, 2009, 11:12 AM

Quote:

Originally Posted by goofygrin

They are plastic scoops that mount to the a arm (using the integrated clips and zip ties) that direct air to the calipers. A buddy works at a porsche dealer and gets them for us. About $20/set. Cheaper than the Mitsu ones and about 2x as large.

Got pics?

goofygrin · Oct 6, 2009, 12:06 PM

Quote:

Originally Posted by flyguycfi

Got pics?

I should have gotten the part numbers and taken pictures when I installed them. In fact I said that right as we were pulling the car off the lift.

But sadly, no.

Even held on with two zip ties each, they've survived cone kills in autocross and a pretty big off at the track.