Lexus IS250 rear F-Sport BBK
Well, I'm at it again... I've done the fronts (can be seen here https://www.scionlife.com/forums/showthread.php?t=205927) and now its come time to complete the package and do the rears...to get the brake balance where it should be.
I’ve gotten the Lexus IS250 rear BBK and test fit it to the car…here is what it looks like.

Here is a close-up.

I’ve taken all the measurements and already have the caliper bracket laid out. All I need now is to optimize the weight and finalize the design. Then off to a machine shop to get them made.
As always, you don’t get it all…I won’t have an e-brake…
Maybe another project after I build some custom upper control links for camber adjustment. Does it ever end?
I’ve gotten the Lexus IS250 rear BBK and test fit it to the car…here is what it looks like.
Here is a close-up.
I’ve taken all the measurements and already have the caliper bracket laid out. All I need now is to optimize the weight and finalize the design. Then off to a machine shop to get them made.
As always, you don’t get it all…I won’t have an e-brake…
Maybe another project after I build some custom upper control links for camber adjustment. Does it ever end?
These F-Sport BBKs are built by StopTech…The front is an ST60 caliper and the rear is an ST40 with a 355x32 AeroRotor up front and a 345x28 AeroRotor in back and they are cheaper from Lexus than if you just went out and bought them from an authorized StopTech dealer like Zeckhausen Racing. Just like the TRD BBK offered for the 2nd Gen tC, the TRD BBK is a StopTech ST41 caliper up front only. It’s not a matter of getting a Lexus, it’s the price! If I wanted an IS, I would have gotten one…
Thanks...
Being a machine design engineer by training, an aerospace structural engineer by profession and a gear-head by addiction…it wasn’t all that hard for me to design and build.
We all have our fortes…this one is mine. This is what I like to do on my own time.
Being a machine design engineer by training, an aerospace structural engineer by profession and a gear-head by addiction…it wasn’t all that hard for me to design and build.

We all have our fortes…this one is mine. This is what I like to do on my own time.
Envious! Any chance you may want to make another set to make some $$$?
I wouldn’t mind but take a good hard look at the economics of this mod first.
If you just do a BBK for the rear, you will make the car very unstable under braking…do not do just the rears. You must do the fronts first. This rear BBK is also not compatible with the TRD BBK offered for the front of the gen 2 tC. This rear BBK is significantly more powerful than the TRD BBK and you will still have the same instability problem under braking.
You can buy the TRD front BBK for $1400. A StopTech ST60 caliper with 355x32 AeroRotors BBK is about $3500 from Zeckhausen Racing on line. This is what I’ve got up front on my car but with F-Sport branding. I got the F-Sport front BBK for $2400 and about another $1400 in custom machined parts for a total of about $3800 for just the fronts. If we can get about 10 people here committed for just the fronts, we could only dream of getting the price down to about $3400 to $3500 for the front BBK. This is more than double what the TRDs cost and then another $2800 to $3000 for the rears shown here… You would have to be very serious about braking power to invest $6500 in just brakes. Any racers here?
If you just do a BBK for the rear, you will make the car very unstable under braking…do not do just the rears. You must do the fronts first. This rear BBK is also not compatible with the TRD BBK offered for the front of the gen 2 tC. This rear BBK is significantly more powerful than the TRD BBK and you will still have the same instability problem under braking.
You can buy the TRD front BBK for $1400. A StopTech ST60 caliper with 355x32 AeroRotors BBK is about $3500 from Zeckhausen Racing on line. This is what I’ve got up front on my car but with F-Sport branding. I got the F-Sport front BBK for $2400 and about another $1400 in custom machined parts for a total of about $3800 for just the fronts. If we can get about 10 people here committed for just the fronts, we could only dream of getting the price down to about $3400 to $3500 for the front BBK. This is more than double what the TRDs cost and then another $2800 to $3000 for the rears shown here… You would have to be very serious about braking power to invest $6500 in just brakes. Any racers here?
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