GiroDisc Install

[Davisca455]

I think I have 11 track days on the ST60 rings.
They're getting a little cracky, not horrible but was advised to order up some spares.





I have an event scheduled for Sears Point next weekend, so went into the garage today to install the track pads, and decided to install the GiroDisc rings as well, and make the ST rings the spares.

Clean those hub faces folks:


...and the hats

Before:


After:

[Ximian]

Nice that they include the hardware. The bolts I got from StopTech were pretty low quality, I had to scrape off a layer of coating from the threads so it wouldn't mess up the install.

[MaX PL]

so what exactly was wrong with the ST60 rings? that looks normal.

[Davisca455]

Originally Posted by MaX PL

so what exactly was wrong with the ST60 rings? that looks normal.

Nothing is actually "wrong" with them.

https://www.essexparts.com/news-blog...-my-iron-discs
^^^^^Very helpful document!

I had emailed David Zeckhausen to ask his opinion on the condition of the ST rings.
He said they were still ok, but that it would be an appropriate time to get some spares on order, so that's what I did.

Right after I placed the order, I read on the forum where someone broke a ring at the track, which ended their day early, so now their policy is to bring spare rings.
Their logic was something like "Better to install a spare ring on the lunch break, rather than having your day end early and on a flatbed."

So yesterday, when I went into the garage to install my track pads, I looked at the box of new rings just sitting there on the workbench, and I thought "Might as well make the ST rings the "spares", and just install the new ones."

It's one thing to push the rotors at Thunderhill East, there isn't much penalty for an off, but it's entirely different at Sears Point, where an off there will likely have very painful consequences.

[derbo]

I love the runout tag!

[Davisca455]

Originally Posted by derbo

I love the runoff tag!

YES!
Max Runout of 6/10ths of one thousandths of an inch!

Love that GiroDisc makes their inspection process visible.
They make some NICE equipment.

[M eyedoc]

Good timing. Just replaced with the same last weekend. Not on the car yet as I hope to finish engine/transmission mounts, tie rods and control arm replacement project later today. GiroDisc hardware is big improvement over Stoptech. Figured I would refresh as much as possible for upcoming Daytona event in a few weeks!

[spxxx]

Just inspected mine and we're in the same boat, where did you order yours from? I need to confirm size as most of the 355mm rotors are 32mm but I'm pretty sure my current ST40R's measured ~35mm a while back.

[Davisca455]

Originally Posted by spxxx

Just inspected mine and we're in the same boat, where did you order yours from? I need to confirm size as most of the 355mm rotors are 32mm but I'm pretty sure my current ST40R's measured ~35mm a while back.

I ordered them from an eBay seller (autocat51) that actually had them in stock, but mine are the 380mm diameter x 35mm thick.
It appeared they were the last of three sets they had.

Everywhere else I looked there were none in stock.

I've since heard from Adam Hume at buybrakes.com.
He checked with GiroDisc and they told him their lead time is 2 weeks, but again that was for the ST60 rings.

But Adam's price is the lowest I've seen as well, so I'd highly recommend contacting him to place the order.

[M eyedoc]

Mine from Bimmerworld. In stock as well

[Davisca455]

Originally Posted by M eyedoc

Mine from Bimmerworld. In stock as well

Ya, looks like GiroDisc has them back in stock now.
But BW says out of stock at the moment.

https://www.bimmerworld.com/Slotted-...sc-380x35.html


To anyone that hasn't purchased yet, Adam's prices are still significantly lower than what I'm seeing advertised at the moment…

[Davisca455]

Went out in the country this morning to apply a little pad schmear.
All set now.

[M eyedoc]

I'm jealous. Still buttoning everything up. Finally getting to the brakes. Your bearing hubs look great! I often say I'm going to do that, but always seem to get tired from the project before beautifying things...

[Davisca455]

Originally Posted by M eyedoc

I'm jealous. Still buttoning everything up. Finally getting to the brakes. Your bearing hubs look great! I often say I'm going to do that, but always seem to get tired from the project before beautifying things...

I take the extra time to knock off the high spots.
In my mind, it makes me feel like the rotor assembly has the best chance to run true.

It actually doesn't take that long though.
I use Crocus Cloth (abrasive with a cloth backing instead of paper), and it makes quick work of at least the high spots of the corrosion.

[DrFerry]

Nice job and nice brakes too. I recommend removing the inner metal dust shields and getting some cool air ducting to the center of the rotors - if you've not already done so. A little bit of cool air goes a long way towards keeping brake temperatures down in my experience as well as improving the life of braking components.

Additionally, heat from the rotor migrates to the hub, then into the wheel and then into the tires. So cool air brake ducting tends to aid tire temp stabilization and hot pressure ceiling too. Just my two cents.

Enjoy, but be careful out there too in your G Power mobile 🙂

[Davisca455]

Originally Posted by DrFerry

Nice job and nice brakes too. I recommend removing the inner metal dust shields and getting some cool air ducting to the center of the rotors - if you've not already done so. A little bit of cool air goes a long way towards keeping brake temperatures down in my experience as well as improving the life of braking components.

Additionally, heat from the rotor migrates to the hub, then into the wheel and then into the tires. So cool air brake ducting tends to aid tire temp stabilization and hot pressure ceiling too. Just my two cents.

Enjoy, but be careful out there too in your G Power mobile 🙂

I didn't remove the heat/dust shields yet.
Generally I'm pretty conservative with my mods (blower was on the car when I bought it), so my philosophy is to only address actual issues as they appear.
Other than rod bearings of course.

My thoughts on the heat shields were that they might protect the suspension pivots, so I decided I'd wait and see if the inner face of the rotor was experiencing accelerated grief before removing them.

For ducting, I have started to concept what some tight fitting aluminum sheet metal pieces could look like, but no real plan yet.
I'm just not excited about spending money for something I can possibly fabricate myself for "free".
Plus, making stuff like that is fun for me…"Hey kids, it's Arts & Crafts Time!"

[DrFerry]

Originally Posted by Davisca455

I didn't remove the heat/dust shields yet. Generally I'm pretty conservative with my mods (blower was on the car when I bought it), so my philosophy is to only address actual issues as they appear. Other than rod bearings of course. My thoughts on the heat shields were that they might protect the suspension pivots, so I decided I'd wait and see if the inner face of the rotor was experiencing accelerated grief before removing them. For ducting, I have started to concept what some tight fitting aluminum sheet metal pieces could look like, but no real plan yet.
I'm just not excited about spending money for something I can possibly fabricate myself for "free".
Plus, making stuff like that is fun for me…"Hey kids, it's Arts & Crafts Time!"

Came across this custom solution. Others exist but I think I would like this one a lot.
.
https://www.m3post.com/forums/showpo...29&postcount=4
.

.

.
https://www.m3post.com/forums/showthread.php?t=1962104
.
Kudos to PrimeBMW

[bigjae1976]

Maybe I'm missing something but replacing rotors after 11 days? That seems extremely premature. Did you measure the rotor thickness? They look like they are a looooong way off from replacing. I've done about 20 days and 60k street miles and my stoptech drilled rotors are cracking like yours but are still .3mm above min thickness. I do over 60 days on my E46 Stoptech BBK before the rotors are anywhere near min thickness.

If the runout is .0006" that is 6 ten-thousandths of an inch you would need an extremely accurate jig and mill to improve upon that. The cost would also be astronomical.

[Davisca455]

Originally Posted by bigjae1976

Maybe I'm missing something but replacing rotors after 11 days? That seems extremely premature. Did you measure the rotor thickness? They look like they are a looooong way off from replacing. I've done about 20 days and 60k street miles and my stoptech drilled rotors are cracking like yours but are still .3mm above min thickness. I do over 60 days on my E46 Stoptech BBK before the rotors are anywhere near min thickness.

If the runout is .0006" that is 6 ten-thousandths of an inch you would need an extremely accurate jig and mill to improve upon that. The cost would also be astronomical.

Correct, they aren't done yet.
It was recommended that I get some spares on order, so I did.
I just decided to mount up the GiroDisc and to make the ST rings the spares.

To many things to splatter into at Sears Point if a rotor were to let go, so erring on the side of caution.

And dang, that is a fun track!
Highly recommended!