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So i come across these OEM sized drilled rotors, from canada. They come with all 4 rotors, for right around 190$ shipped. The company is in canada. My rotors are badly warped from the previous owner, and they need replacing so i figured a small upgrade wouldnt hurt. But will they be worth it? Also what are some good pads?. stopping power/longevity are important.

any answers are greatly appreciated

Drilled rotors are a bit prone to cracking, but I think its usually because people dont heat cycle them proporlly when breaking them in.

I'd choose slotted over dirlled.

Drilled over smooth.

IMO.

Well, supposedly some cross-drilled rotors are more prone to cracking than others, because the quality of the machining varies widely. Since these ones are cheap, I would probably avoid them.

I have no firsthand experience with cross-drilled rotors, but I have seen many peoples' holey rotors crack or warp seemingly more easily than they should have. Maybe they were all cheap parts; I don't know.

Wait a second -- you don't want those rear rotors anyway; they're not for turbo models.

I think a small upgrade would be to use OEM or OEM-type rotors (maybe cry-treat them; Alpine Cryogenics in Moosic isn't too far from you and gave me a good price on mine) and high-performance pads.

Unfortunately stopping power and longevity are usually tradeoffs, so you don't often find them both in the same product. For example, I use Axxis Ultimate pads, which are ceramic. They stop really well, but by the time the pads are worn out, so are the rotors. There are probably several threads already here about pad choice, so maybe you can find good advice in them.

Steer clear of cross-drilled rotors. You will never utilize the cross-drilled part of them unless it is for looks. Current pads don't off-gas like the ones made in the 30's - 40's. The rotors WILL crack, it just a matter of when.

Hawk HPS's are very nice pads. Make sure you look up bedding procedures for the pads and how to season the rotors or you will end up with the same problem you have now.

Thanx for all the great info guys! I think for now, ill prolly go wit some oem replacements. when i get a job and shit ill worry about the upgrades. Need to go faster before i need better stopping power

Brat4by4 wrote:Steer clear of cross-drilled rotors. You will never utilize the cross-drilled part of them unless it is for looks. Current pads don't off-gas like the ones made in the 30's - 40's. The rotors WILL crack, it just a matter of when.

Hawk HPS's are very nice pads. Make sure you look up bedding procedures for the pads and how to season the rotors or you will end up with the same problem you have now.

word.

Drilled rotors are stupid and anyone who thinks they'll somehow improve braking needs to get kicked in the head. Slotted rotors apparantly are better for keeping the pad clean if you're rallying or something.

Stoptech has lots of technical papers on their website if you'd like to learn more about brakes. I especially recommend the one on bed-in theory.

I heard that solid rotors are best for rallying because slotted rotors could theoretically get pebbles stuck in them

Less metal in the rotor is less to absorb heat.

Cryo-treat OEM rotors for that price and you won't warp them until you wear through them. Even using aggresive pads won't kill the rotors as quick. I'm seriously tossing around the idea of starting my own cryo-place, so impressed was I with my treated rotors. Now I have cryo-treated WRX rotors and I expect them to last well beyond my need to upgrade to even bigger brakes. Hell, these things don't even seem to rust as quickly for some reason (though that may just be my bias imagining that - I've not conducted a test between treated and non-treated in terms of rust resistance). I'm going to be ordering cryo-treated rotors for my Mazda3 now since I've already warped them (15k. Typical for me on non-treated).

How much do the cryo-treated rotors run

Depends greatly on where you go. I think I paid $25/rotor, but even at 3x the price, they lasted about 8x longer with me (4 years vs. 6 mos.). The OEM ones were so worn out when I replaced them that they were almost through to the vents. Still didn't pulse that bad.

if those are the ones i'm thinking of, they're actually pretty damn good rotors. a friend of mine ordered a set of them for his 95 impreza off ebay (think it was $100 for the set and $50 shipping) he's been using them for a bit under a year now and says they're great especially for the money. and if you want them to last even longer, you could cryo-treat those.

i thought the whole deal with drilled rotors was if the holes were cast in initially or drilled afterwards?

Either way, holes dont encourage even expansion of the rotor as it heats up.

Drilled rotors serve two purposes: Bling in most cases, and weight saving (in porsche's case)

Either way...for your subaru....neither are pertinent enough for me to recommend you get them.

There can be more then one reason for the cracking, but the main issue that causes it is the fact that the drilled holes create stress risers (points in the material where stress must increase due to discontinuity in the materials physical layout) in the material.

How much stress the material can withstand can be traced back to material properties, possibly maching, and so forth.

Bottom line....just stick with blank rotors.

I've got a write up on my site that goes into some detail about why not to use drilled rotors. It really needs to be updated....along with the rest of the site....but time has not permitted.

I agree with Brat4by4 when he said you probably won't ever experience the benefits of gas-evacuating rotors, unless you've got an EJ257 swap or something...