Rear Disk Worth It?

[CarrollComputing]

I have been thinking about removing my rear drum brakes and replacing them with disks, as well as upgrading my front rotors and calipers while I am at it. Do you think it would be worth it? I have always preferred the feeling of 4 wheel disk brakes but I just want to see if anyone else has tried this on the sonic and if what they got out of it was worth the time and money spent replacing them.

 

[sonic13rs]

Suggest: Go to a dealer who has an RS and test drive.

 

[laborsmith]

I remember a GM Media video where chief engineer John Buttermore is describing items that make the RS unique and he says the rear discs are more for appearance than for performance. He was doing a walk around a white RS about a month or so before the start of regular production. Maybe someone who knows how to use u-tube could post the link.

Laborsmith

 

[Macehammer]

Yeah.

Cheaper to replace/repair though... so might as well get them, since they come along with the rest of it...

 

[ahtoxa]

I have been thinking about removing my rear drum brakes and replacing them with disks, as well as upgrading my front rotors and calipers while I am at it. Do you think it would be worth it? I have always preferred the feeling of 4 wheel disk brakes but I just want to see if anyone else has tried this on the sonic and if what they got out of it was worth the time and money spent replacing them.

If you are not going to use this car on the track, then no - not worth it.

Drums may be old tech and are slightly more annoying to work on but they do a fine job braking. I bet that all other things equal, one would not feel a difference in stopping with two identical cars where one has drums on the back and one has disks. Again - in regular daily driving or spirited driving on public roads.

Bigger brakes don't do much for a non-track car either. Why? because a non-track car is not likely to need the better heat dissipation properties of larger brakes. If you think about it - you do not get better stopping power because you are limited by traction that your tire can provide and ANY stock brake system on the market today can easily provide enough braking force to lock up the wheels repeatedly for a few times w/o overheating.

So back to square one - larger brakes will really only be useful in a track application where one requires constant, repetitive high speed braking that generates a lot of heat that needs to be dissipated.

On a street car, you're only increasing un-sprung weight, which can and will make handling worse.

 

[Dirt55]

I remember a GM Media video where chief engineer John Buttermore is describing items that make the RS unique and he says the rear discs are more for appearance than for performance. He was doing a walk around a white RS about a month or so before the start of regular production. Maybe someone who knows how to use u-tube could post the link.

Laborsmith

2013 Sonic RS Exterior | Sonic | Chevrolet - YouTube

Here it is, states you get better pedal feel

 

[2FR35H]

If you are not going to use this car on the track, then no - not worth it.

Drums may be old tech and are slightly more annoying to work on but they do a fine job braking. I bet that all other things equal, one would not feel a difference in stopping with two identical cars where one has drums on the back and one has disks. Again - in regular daily driving or spirited driving on public roads.

Bigger brakes don't do much for a non-track car either. Why? because a non-track car is not likely to need the better heat dissipation properties of larger brakes. If you think about it - you do not get better stopping power because you are limited by traction that your tire can provide and ANY stock brake system on the market today can easily provide enough braking force to lock up the wheels repeatedly for a few times w/o overheating.

So back to square one - larger brakes will really only be useful in a track application where one requires constant, repetitive high speed braking that generates a lot of heat that needs to be dissipated.

On a street car, you're only increasing un-sprung weight, which can and will make handling worse.

I say depending on the price it could be worth it. By your logic might as well not even do any mods to a car period actually we all might as well all go old school and be driving in ford model t's because you know what we aren't going to see much difference in normal day to day driving. Any improvement is good and worth while because its the little things that amount to a lot in any given situation.

 

[Opticon]

By your logic might as well not even do any mods to a car period actually we all might as well all go old school and be driving in ford model t's because you know what we aren't going to see much difference in normal day to day driving. Any improvement is good and worth while because its the little things that amount to a lot in any given situation.

Actually he is exactly right. A rear disk conversion would be a complete waste of money on a car that doesn't see repetative hard braking. Which answers the OP's question nicely.

I'll go a step further and say that a better bang for your braking buck would be HPS front pads and some slotted (or J-hook) rotors.

 

[Natesriv]

Is it even a direct exchange? The ABS and proportioning valves are all designed for the rear drums... would the cars computer(s) need to be changed?...
I'd love to have discs, simply for the look, but as everyone states, for regular use, drums will meet the job.
Just remember to work on one side only!!!

 

[usayit]

Why oh why would they still make cars with drum brakes? Seriously.... from a design/manufacturer point of view what is the reason to even continue using drum brakes on any car?

Drum brakes on my old Jeep YJ was a PITA to work on. In the time I spent on the rears drums, I could finish all four corners of my miata.



Oh yeh.. but I agree.. they do a good enough job for this application.

 

[Natesriv]

exactly! what cost savings did GM see from that?
I haven't worked on drums in years.. and even then I had no clue! I can do disc brakes all day...drums...that's going to be a learning curve... not impossible mind you, just don't have the know how yet

 

[laborsmith]

2013 Sonic RS Exterior | Sonic | Chevrolet - YouTube

Here it is, states you get better pedal feel

Thank you for finding the link. John Buttermore is a multiple year national SCCA champion so I suspect he has a good idea of what he is talking.

To the OP, there is a thread that is more specific and I believe things like the proportioning valve were the same, rear disk or rear drum. Brake lines too but I believe there was something needed to make putting the RS rear brakes on a non RS Sonic but can not recall specifically. If you are serious I recommend reading through that thread although it is quite long it is also quite detailed and has a lot of good information, including diagrams.


Laborsmith

 

[ChrisJ]

Why oh why would they still make cars with drum brakes? Seriously.... from a design/manufacturer point of view what is the reason to even continue using drum brakes on any car?

Drum brakes on my old Jeep YJ was a PITA to work on. In the time I spent on the rears drums, I could finish all four corners of my miata.



Oh yeh.. but I agree.. they do a good enough job for this application.

exactly! what cost savings did GM see from that?
I haven't worked on drums in years.. and even then I had no clue! I can do disc brakes all day...drums...that's going to be a learning curve... not impossible mind you, just don't have the know how yet

Our 06 Vue had rear drums my Sonic has rear drums and the Cruze has rear drums.

I don't know the cost difference but what I do feel safe in assuming is GM knows the cost difference and did what was the best bang for the buck. As others have said the main difference is pedal feel. You may also get water in them under some conditions but other than that drums on the rear are fine.

I haven't looked but I've got a feeling GM isn't the only one using drums on the rear of a car in 2012-2013.

 

[Natesriv]

No, other's are too.. It may save costs, but there's more complexity, and parts in a drum setup compared to a disc (a nice single piston one)

 

[River_Rat]

Am I the only one that thinks working on drums is easy? Complex? You've got shoes, wheel cylinders and springs.

 

[Macehammer]

In my experience labor costs on repairs for drums is higher than disks. Not a night and day difference, but a difference nonetheless. Can't remember if it is part or labor cost....

So how often are you gonna need repairs?
Are you going to do them yourself?
How long are you gonna own this car?
Are you considering any of this for aesthetic reasons?

These are all some questions to ask prior to swapping out your drums for disks. RS drivers don't need to worry, with 4 disks.

And since most people here talk about shedding weight, and not towing (towing, in a sonic haha) or racing, upgrading to bigger disks probably makes no sense for you.

 

[sx sonic]

Am I the only one that thinks working on drums is easy? Complex? You've got shoes, wheel cylinders and springs.

It depends. Chevys usually aren't too bad. I go to church before doing ford drums, they usually seem to have double the springs and hardware.

personally I think the cost of a rear brake swap is very large for the meager gains (feel,fade resistance, and serviceability).

That money would be much better spent on tires.... Which suck.

JohnT has been autocrossing the sonic for awhile and his biggest gripe was the stock tires. He had some qualms with braking but if my memory is correct it was brake fade that he fixed with pads, fluid, and rotors. I don't recall him having much issues with the rear drums, however my memory is far from infallible.

I'd ask him his thoughts as he is very knowledgeable and being an autocrosser knows the ins and outs of tires, suspension, and BRAKES. If he doesn't think It's worth the swap for his purposes then it definitely isn't worth it for a daily driver.

 

[usayit]

Lighter rims would also probably make a bigger difference.... unsprung weight.

 

[ahtoxa]

I say depending on the price it could be worth it. By your logic might as well not even do any mods to a car period actually we all might as well all go old school and be driving in ford model t's because you know what we aren't going to see much difference in normal day to day driving. Any improvement is good and worth while because its the little things that amount to a lot in any given situation.

You're generalizing a point that was very specific. Just because the mod in this specific (and very particular) case isn't beneficial, it doesn't mean that all other mods that auto enthusiasts have ever done are a waste and we all should drive model T's.

That doesn't make sense...

 

[rdss]

You're generalizing a point that was very specific. Just because the mod in this specific (and very particular) case isn't beneficial, it doesn't mean that all other mods that auto enthusiasts have ever done are a waste and we all should drive model T's.

That doesn't make sense...

A tune does not improve driveability and power and is completely unbeneficial! Becuase Model T!!