Type-R rear brakes on Si

[Syntek]

Some digging around here I found out that Si's are able to use the Type-R pads, which tells me they're literally the same caliper for both?

With that being said, is it possible to put the Type-R rear rotors on the Si since they are supposedly larger than the Si rotors? Curious to see if there's an adapter needed to move the caliper further up or away to fit the rotor.

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[zspeed]

The Type R uses 5x120 holes while the Si and other 10th gen Civics uses 5x114.3 holes. If you can find an equivalent diameter of rotors in what the Type R uses but in a 5x114.3 hole setting, go for it. AFAIK, you can just use the rear caliper brackets from the Type R if you’re planning to go for it.

 

[L8apex]

You’re talking rear calipers right? Because I’ve never seen pads for a floating caliper (Type R front) fit in a sliding caliper (Si front). Generally those pad shapes are different especially in how they’re retained in the caliper.

 

[Syntek]

Rear only. I have a genesis brembo retrofit for the front.

 

[KingOfBrussels]

It looks like aftermarket pad companies are listing the same pads for the rear calipers of the Si and Type-R but Honda lists different part #s for the Si and CTR rear calipers and pads.

Carbotech for example lists the rear pad shape for both trims as CT1878- and whatever compound you choose.

FYI on the Honda part #s...

Calipers
Si - 43018-TBF-A02 & 43019-TBF-A02
CTR - 43018-TGH-A02 & 43019-TGH-A02

Pads
Si - 43022-TBF-A01
CTR - 43022-TGH-A01

Not sure what's different about the factory parts but even though they might be different in some kind of way, at least according to Carbotech the pads are the same shape.

Found specs on the Type-R rear rotors here.

https://www.rockauto.com/en/moreinfo.php?pk=10622880&cc=3443266&jsn=816
https://www.rockauto.com/en/moreinfo.php?pk=10695756&cc=3443266&jsn=818

It's a 304.4mm diameter and 10.9mm thickness with a 5x120 bolt pattern. I'd have to go down another rabbit hole to find a car with a rear rotor with those dimensions but 5x114.3 bolt pattern, but if you feel like searching that's the starting point.

 

[Syntek]

It looks like aftermarket pad companies are listing the same pads for the rear calipers of the Si and Type-R but Honda lists different part #s for the Si and CTR rear calipers and pads.

Carbotech for example lists the rear pad shape for both trims as CT1878- and whatever compound you choose.

FYI on the Honda part #s...

Calipers
Si - 43018-TBF-A02 & 43019-TBF-A02
CTR - 43018-TGH-A02 & 43019-TGH-A02

Pads
Si - 43022-TBF-A01
CTR - 43022-TGH-A01

Not sure what's different about the factory parts but even though they might be different in some kind of way, at least according to Carbotech the pads are the same shape.

Found specs on the Type-R rear rotors here.

https://www.rockauto.com/en/moreinfo.php?pk=10622880&cc=3443266&jsn=816
https://www.rockauto.com/en/moreinfo.php?pk=10695756&cc=3443266&jsn=818

It's a 304.4mm diameter and 10.9mm thickness with a 5x120 bolt pattern. I'd have to go down another rabbit hole to find a car with a rear rotor with those dimensions but 5x114.3 bolt pattern, but if you feel like searching that's the starting point.

Appreciate it. I wasn't too sure if it was just as simple as putting on the Type-R rear bracket and just putting on the upgraded rear rotor and calling it a day.

As it is right now, I am running the "upgraded" CTR rear-pads on my car, if I'm able to upgrade the rear rotor as well to the same dimensions as the CTR with just a bracket modification (and obviously the proper bolt pattern) it would be a relatively cheap upgrade to do

 

[vtecr]

If you're stuck for options you could always get the CTR discs redrilled to your PCD. it's a pretty straightforward process and given that both patterns are 5 stud, you should be easily able to space the holes away from eachother.

 

[KingOfBrussels]

I've been trying to find something that'll match the CTR 304.4 x 10.9mm rotor size.

The Si is 282 x 10mm for reference.

So far the closest match I've found is 4th gen CR-V / 2nd gen RDX which is 304.6 x 9mm.

But going down in thickness isn't ideal, and I'm not sure if the CTR calipers are slightly different to accommodate the thicker rotor while using the same pad shape as the Si.

The search continues...

 

[Syntek]

I've been trying to find something that'll match the CTR 304.4 x 10.9mm rotor size.

The Si is 282 x 10mm for reference.

So far the closest match I've found is 4th gen CR-V / 2nd gen RDX which is 304.6 x 9mm.

But going down in thickness isn't ideal, and I'm not sure if the CTR calipers are slightly different to accommodate the thicker rotor while using the same pad shape as the Si.

The search continues...

Definitely, but also would 1mm make that much of a significant difference if they're being used for the rears anyway? I don't see any real differences between calipers either except one is painted red. In any case thank you for your help. This would be an upgrade I do later on down the line when I run through my recently purchased rear rotors

 

[KingOfBrussels]

Well the CRV/RDX rotor is only 1mm thinner than Si rotors but 2mm thinner than CTR.

It looks like according to this thread...

https://www.civicx.com/forum/threads/ctr-fk8-brakes-on-si-ex.37330/

The CTR rear caliper is aluminum vs. iron on the Si, and the CTR pads are the same shape as Si, but thinner, most likely to work with the thicker rotor rather than changing something about the caliper itself.

Besides looks, the reasons to go for a bigger rotor are higher heat capacity through increased mass, and more leverage for the caliper to slow down the wheel by moving it farther away from the center of the hub. If you go to a thinner rotor that's lowering the mass, so even with a larger diameter you might not gain heat capacity. The CRV/RDX rotor being thinner would maybe be a looks upgrade with a little more leverage but probably not any more heat capacity than Si. Certainly less than CTR which is same diameter but 2mm thicker.

The other question here is how is the R caliper moved out from the hub vs. the Si. It could be either the mounting tabs on the hub, or the caliper bracket, or both.

Part #s....

Caliper Bracket ("anchor" in the parts catalog)
R: 43220-TGH-A01
Si: 43220-TGN-G01

Caliper
R: 43018-TGH-A02 & 43019-TGH-A02
Si: 43018-TBF-A02 & 43019-TBF-A02

Hub
R: 42200-TGH-A01
Si: 42200-TBA-A01

The brackets are the exact same price. The R hubs are about double the cost of the Si and the R calipers are more expensive as well. Could be due to aluminum vs. iron in each case. Not sure.

Somebody would probably have to measure the hubs and caliper brackets to figure out what exactly moves the caliper farther out, then we could figure out what combination of parts would be needed to move the Si caliper to work with the R size rotor (either by redrilling the R rotor or finding an equivalent with the correct bolt pattern).

 

[BoostinIX]

What use case? I.e. DD, racing, etc. Are you actually benefiting from all that cost and work? Would imagine the diminished return scale is steep.

 

[Syntek]

What use case? I.e. DD, racing, etc. Are you actually benefiting from all that cost and work? Would imagine the diminished return scale is steep.

The car is being tracked more, the only changes if it's a straight forward process would be rotors and the anchor brackets

 

[KingOfBrussels]

I found a rotor possibility but not sure this would actually work and also still unsure of what exactly moves the caliper farther out from the hub. But hey it's some kind of progress so here goes.

2017-up Kia Sportage 2.0T has 302 x 10 mm rear rotors.

I'm not positive these will work as there are 2 different versions depending on if the car is equipped with manual or electric parking brake and the hat heights on both might be too different from the Si. The electric parking brake version is 31 mm and manual parking brake is 54.4 mm. The Si rear rotor hat is 37.6 mm.

For reference the hat height on Si front rotors is 47.2 mm vs 44 mm for the Nissan Rogue w/ 3rd row rotors used in the Genesis Brembo caliper conversion, or 49.1 mm for the 350Z Brembo rotors used in the Acura RL caliper conversion. I don't really know if the hat height will change the offset or what.

Anybody have an ideas on how that rotor hat height comes into play?

 

[circuit.heart]

The car is being tracked more, the only changes if it's a straight forward process would be rotors and the anchor brackets

Just upgrade pads. If you turn off VSA, the rear brakes never get exercised enough to even get hot. I kept stock pads in the rear of my time attack car so that I'd at least have some bite when it's cold. If you managed to get more extended track time out of your car than me, even a "basic" track compound won't get hot enough to fade.

I found a rotor possibility but not sure this would actually work and also still unsure of what exactly moves the caliper farther out from the hub. But hey it's some kind of progress so here goes.

2017-up Kia Sportage 2.0T has 302 x 10 mm rear rotors.

I'm not positive these will work as there are 2 different versions depending on if the car is equipped with manual or electric parking brake and the hat heights on both might be too different from the Si. The electric parking brake version is 31 mm and manual parking brake is 54.4 mm. The Si rear rotor hat is 37.6 mm.

For reference the hat height on Si front rotors is 47.2 mm vs 44 mm for the Nissan Rogue w/ 3rd row rotors used in the Genesis Brembo caliper conversion, or 49.1 mm for the 350Z Brembo rotors used in the Acura RL caliper conversion. I don't really know if the hat height will change the offset or what.

Anybody have an ideas on how that rotor hat height comes into play?

Rotor hat height is critical. If you're off by 1-2mm, a fixed caliper might have enough piston travel to compensate, but a sliding caliper will probably hit the bracket to the rotor and your wheel bearing is toast.

If you know that the wheel hub dimensions are compatible between CTR and Si, then redrilling a CTR rotor is the easiest way to go. You can do it with a hand drill and some sharp cobalt bits. Otherwise, better to find specs on the CRV rotor you mentioned earlier. 1mm thinner is not going to hurt heat capacity in the rear.

The biggest thing you guys are not considering is brake bias. The factory brake bias is pretty well tuned to a stock car on stock tires. If you upgrade tires for the track, you need more FRONT bias, not REAR bias, as the car will dive harder under braking. It's not fun to go into a corner full opposite lock when the rear tires lock up on corner entry.

 

[KingOfBrussels]

The thinking here was to do a basic cheap parts swap upgrade on the rear to balance out adding a BBK to the front. Not on its own.

That RDX/CR-V rear rotor has a 60.7mm hat so also not close.

https://www.carid.com/durago/solid-1-piece-brake-rotor-mpn-br900390.html

I've gone down this parts catalog rabbit hole plenty, I think even though the R caliper uses the same pad shape, getting a similar dimension of rotor on an Si is not a simple parts swap, at least as far as I've managed to search.

There's actually not a ton of rear pad upgrades, only performance options I've only seen are EBC & Carbotech.

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