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View Full Version : Slotted vs Cross Drilled vs Blank Rotors


DaveInDenver
04-16-2009, 09:37 AM
I'm preparing to replace my rotors (they hit min thickness last refresh time) and this has been bouncing around in my head for a number of years. Always have used OEM rotors, nothing fancy. In particular the front, but generally I feel that the stock rotors are good quality and Jerry has always quoted prices that are comparable to NAPA on similar quality rotors and drums (i.e. Aisin vs Raybestos vs Delco, etc). I am willing to pay for a good name rotor no matter who makes it and I think if there is one place not to cheap out it's gotta be brakes. In some case (like drums) the OE parts are preferred because not all the aftermarket stuff has the two threaded holes for popping them off. Friggin' brilliant, that.

Anyway, just wanted throw it out for discussion. The upside to plain blanks is they have the maximum surface for braking and when going slow is all about plain old friction. Even with just a 4.70 case I can barely keep the truck from moving while standing on the brakes, so a reduction in surface by even a few percent due to slots or holes doesn't make sense. I already have a 15/16" master cylinder (gotta love having stock IFS brakes!), although I have the big/small calipers being a 4 cylinder. I'm upgrading those to dual big pistons from a 4Runner and putting on a 1" MC. That should increase rotor pressure by about 10%~15%.

Slots and/or drilling have reasons, although I'm not sure a built 4WD can really see that benefit. Never off highway, that's pretty sure. Since my truck spends 90% of it's time on the highway, I've never been able to fully convince myself that slots, for example, might not be a bad idea. I mean if they do allow some effect, like 5% shorter braking, then in a panic stop that might be good. I personally think cross drilling doesn't interest me (too much risk of cracking rotors IMO), but slots, I dunno, maybe.

I was also thinking about the cryo treated ones. Uncle Ben would I think cryo treat his whole truck if he could, but I've heard too many people I trust say it works to poo-poo it out of hand.

In the end I will probably just buy what Jerry is selling, but thought it would be good to see what the club sages have to say anyway.

Telly
04-16-2009, 09:54 AM
I purchased my 97 80 two years ago with drilled and slotted front rotors already installed. I've never had any braking issues on the rocks in the Moab heat and my pads seems to be lasting longer than past experience but I have no idea if that is related to the rotors.

I'm pleased with mine.:cool:

Doug

Crash
04-16-2009, 11:10 AM
Dave, I've had DBA drilled/slotted on the 62 for about six years now and they have worked great from day one. Never any signs of warpage and have never experienced any problems with crud in the drill holes. That said, I would go with slotted only next time around but M-A-F didn't have slotted only at the time the ones I have were purchased. You've seen all the reasons for and against and you really can't go wrong with the stock discs, either, so it's just a personal choice with $$ always a factor. I have, on the other hand, tried all sorts of pads and, while some have merits over others, you just can't beat stock pads for all around stopping power and longevity.

nakman
04-16-2009, 11:22 AM
I agree with Steve, I've got slotted & drilled on the 80 and while I haven't had to even think about my brakes for like 4 years, I have taken the time to drill out all the little holes to clean all the crud out. Kane Creek will fill some of those holes with red mud, period. While it hasn't been a stopping issue, I still worry it's not the best thing for the pads and/or rotors, if nothing else it's causing a slight weight imbalance issue, yes I know 1 ounce near the center is nothing compared to the big lugs of a 75 pound tire. Still, it's something to lie awake thinking about.

long story short, next time I need rotors I'm going slotted only.

DaveInDenver
04-16-2009, 11:23 AM
I have, on the other hand, tried all sorts of pads and, while some have merits over others, you just can't beat stock pads for all around stopping power and longevity.
This is an interesting point. I used EBC green pads last time. These are the entry level EBC pad, supposed to be better than stock but not full rally car sort of thing. I think these are the reason (1) I have less than great crawl braking and (b) my rotors warped. When I put the system together, stock blanks freshly machined and higher pro pads, on the first few stops I just about broke my nose coming off the highway. They stopped NOW! But the rotors had warped by about a month later and now they seem to have a glaze (my braking is not great at the moment). The Rubithon was the first real off highway trip with them I sometimes had to use both feet to get it to stop. I think they are just too hard to work well until they get hot. So I think pad material is major determiner here and this time I am planning just standard issue semi-metallic OE type. I am getting rebuilt loaded calipers, so probably won't be Aisin this time, though.

Interesting about the slotted rotors. Hmmm....

FWIW, prior to the EBC experiment I ran a complete OE system with Carquest pads (their Gold I think, just whatever decent level they had) and that went about 5 years or so with zero drama.

Red_Chili
04-16-2009, 12:20 PM
I think the plain rotors will do you just fine on your gen minitruck. I've not heard of advantages to the others, again, on your gen minitruck.

I do know that experience varies with other years however, in particular, the newer 4Runners ('96+) (and I would bet, 80s). I have no experience with those. But consider the vehicle a friend has before applying his advice to your truck.

I'm upgrading those to dual big pistons from a 4Runner and putting on a 1" MC. That should increase rotor pressure by about 10%~15%.

Be sure to also upgrade to the V6 vacuum assist. DAMHIK. It's possible your year already has a larger VA than mine did, but believe me, that made as much difference as going with a 1" MC. You can only stop as well as your mechanical advantage permits.

Crash
04-16-2009, 12:44 PM
<snip>
I do know that experience varies with other years however, in particular, the newer 4Runners ('96+) (and I would bet, 80s). I have no experience with those. But consider the vehicle a friend has before applying his advice to your truck.

<snip>

Bill, are you saying that Tim and I should just not have bothered to offer our input because we don't have trucks the same as Dave's? That's a new twist. :confused:

DaveInDenver
04-16-2009, 01:02 PM
Bill, are you saying that Tim and I should just not have bothered to offer our input because we don't have trucks the same as Dave's? That's a new twist. :confused:
No, I think his point is that from Toyota my truck had good rotors, decent 4 piston calipers, fairly large diameter MC, dual diaphragm booster etc. So going from stock to the V6 brakes is a relatively small upgrade. Solid axle mini trucks had solid (non-vented) rotors, smaller non-finned calipers, 7/8" (or maybe 13/16") bore MC, etc. So his point (I think) is that standard blanks might be a far more marginal change compared to the change you guys did or that Dean might do to his pickups. Which is sorta the point of my question, I have pretty good factory brakes to start, a minor downgrade compared to the holy grail of V6 IFS 4Runner or T100 brakes. So slotted and/or drilled might really not be enough improvement to justify the cost, etc. But I take it all into account, maybe even a slight bias towards the opinions of land whale drivers...

Crash
04-16-2009, 01:13 PM
No, I think his point is that from Toyota my truck had good rotors, decent 4 piston calipers, fairly large diameter MC, dual diaphragm booster etc. So going from stock to the V6 brakes is a relatively small upgrade. Solid axle mini trucks had solid (non-vented) rotors, smaller non-finned calipers, 7/8" (or maybe 13/16") bore MC, etc. So his point (I think) is that standard blanks might be a far more marginal change compared to the change you guys did or that Dean might do to his pickups. Which is sorta the point of my question, I have pretty good factory brakes to start, a minor downgrade compared to the holy grail of V6 IFS 4Runner or T100 brakes. So slotted and/or drilled might really not be enough improvement to justify the cost, etc. But I take it all into account, maybe even a slight bias towards the opinions of land whale drivers...

Fair enough, Dave, although I think you are on to something about some bias here. :D One thing I found, maybe before I became aware of discounted OEM prices from our favorite supporting vendors, was that the DBA rotors were on a par, if not less expensive than stock rotors - even if the DBAs were purchased from M-A-F! In other words, that possible improvement might also be less expensive. It pays to shop around for good prices and input as well. I do believe that vented will give better performance and longer service than solid rotors.

DaveInDenver
04-16-2009, 02:18 PM
I do believe that vented will give better performance and longer service than solid rotors.
True, but IFS trucks have always had vented rotors. But 1986 that was pretty much a given.

DBA rotors look to be significantly more (around $20) than the price I get at Burt. Loyalty certainly seems to pay off...

Red_Chili
04-16-2009, 02:24 PM
Bill, are you saying that Tim and I should just not have bothered to offer our input because we don't have trucks the same as Dave's? That's a new twist. :confused:

"Garsh, capt'n, I weren't aimin' ta shoot y'all down now... really I weren't... say capt'n what're ya doin' with that there loaded pistol now? Now, capt'n... :eek:"

No, I didn't say ignore the info, just take the truck into account.

In other words, what you guys say about drilled or vented being OK or not OK in the dirt is valuable and obviously true across all models. Whether they represent an improvement over stock or not in terms of braking force, or whether they warp more easily, *may* be true across most or all models, maybe not. Depends on what you started with, size of calipers, size of MC, size of booster...

As a for-instance: that's why I threw that out about the 96+ 4Runner. I've never warped a rotor on my 4Runner and in fact never needed to turn a rotor really on any '87 - '93 minitruck I've owned. My wife's '97, on the other hand.... the brake systems are very different. So my experience with the '97 regards warping is no help to Dave, but if I had tried slotted or drilled in the dirt, that would apply.

SeewhutImeanVern? Heck I'd NEVER tell someone to ignore Crash! :lmao:

Crash
04-16-2009, 05:11 PM
True, but IFS trucks have always had vented rotors. But 1986 that was pretty much a given.



DBA rotors look to be significantly more (around $20) than the price I get at Burt. Loyalty certainly seems to pay off...

I need a quick reference list to refer to when it comes to minitruck differences, so I'll know that IFS trucks have vented rotors before blindly speaking out of place. Excuse me.

Also, I forgot that you and Dean get the even better than usual discount from Burt so if you find the price there to be better it seems that would indicate the end of the discussion.
:thumb:

Crash
04-16-2009, 05:14 PM
"Garsh, capt'n, I weren't aimin' ta shoot y'all down now... really I weren't... say capt'n what're ya doin' with that there loaded pistol now? Now, capt'n... :eek:"

No, I didn't say ignore the info, just take the truck into account.

In other words, what you guys say about drilled or vented being OK or not OK in the dirt is valuable and obviously true across all models. Whether they represent an improvement over stock or not in terms of braking force, or whether they warp more easily, *may* be true across most or all models, maybe not. Depends on what you started with, size of calipers, size of MC, size of booster...

As a for-instance: that's why I threw that out about the 96+ 4Runner. I've never warped a rotor on my 4Runner and in fact never needed to turn a rotor really on any '87 - '93 minitruck I've owned. My wife's '97, on the other hand.... the brake systems are very different. So my experience with the '97 regards warping is no help to Dave, but if I had tried slotted or drilled in the dirt, that would apply.

SeewhutImeanVern? Heck I'd NEVER tell someone to ignore Crash! :lmao:

Yup, I see what you mean. It all depends. Makes for a lively discussion and something that shouldn't be entered into with mintruck driving engineers without some serious forethought. :thumb:

DaveInDenver
04-16-2009, 08:21 PM
Yup, I see what you mean. It all depends. Makes for a lively discussion and something that shouldn't be entered into with mintruck driving engineers without some serious forethought. :thumb:
Now that you mention that, sure does seem the eggheads trend towards minis. Subzali, Red_Chili, yours truly. Weird. :-/

Crash
04-16-2009, 09:26 PM
Now that you mention that, sure does seem the eggheads trend towards minis. Subzali, Red_Chili, yours truly. Weird. :-/

Noticed that you didn't include Cheeseman in your list, Dave. His head is eggshaped. :hill:
Where's that little icon that indicates a slide right on outta here?
Now watch, when Greg gets back from Europe, my trail leader assignments will change to leading Chicken Flats all three days. Not that there is anything wrong with that.

subzali
04-17-2009, 12:28 AM
I think this is what you want Steve...

:bolt:

...or something to that effect :p:

But now then Dave's making a little bit of a blanket statement throwing me in with all the darksiders...I'm not sure a (inherited) 2wd mini counts for much. 'Specially pretty much 100% stock. Oh well I guess I cross a lot of party lines :D

Red_Chili
04-17-2009, 09:22 AM
You know you are a darksider wannabe... you know you are...

Why, even UB can't get away from mini parts, like a drunk can't get away from the sauce...

:lmao:

Crash
04-17-2009, 02:09 PM
You know you are a darksider wannabe... you know you are...

Why, even UB can't get away from mini parts, like a drunk can't get away from the sauce...

:lmao:

Bill, if you are referring to me then I can tell you I'm no wannabe. I have driven Dean's '80 on the trail and had the opportunity to buy an '85 in great shape from a neighbor at a very good price and passed. Pissed the guy off, as a matter of fact, because he wanted to pass the truck along to a Toyota guy and offered it to me at a giveaway price. I'm just a full sized American that likes the comfort of the larger, whale, if you will, sized Cruisers. There is no doubt in my mind, after having ridden and driven to and from Rubithon last year with Cheeseman in his awesome 4Runner, that the minitruck truly is the Son of Land Cruiser and the heritage is obvious. That the minitruck can wheel the snot out of any trail is a given and, due to its 3/4 scale size, can go places a full size truck can't without exposing more of its body parts to danger. I'm just a Cruiser guy, through and through and if you had full-sized dogs you might be more inclined to be a Cruiser guy too. ;)

Uncle Ben
04-17-2009, 02:55 PM
You know you are a darksider wannabe... you know you are...

Why, even UB can't get away from mini parts, like a drunk can't get away from the sauce...

:lmao:

Because of it it now burns really bad when I pee but I'm certain Steve can help with with a proper exorcism to remove all the dark demons who have scarred my good judgment!

DaveInDenver
04-17-2009, 04:03 PM
I'm just a Cruiser guy, through and through and if you had full-sized dogs you might be more inclined to be a Cruiser guy too. ;)
LOL! The Taz is a husky K9 and prefers (as near as I can tell) the back seat of the XtraCab a lot more than getting thrown around in the back of a FJ40. Now the Luxo Road King of SUVs (i.e. Bart or any 80), well I'm sure it would like the back of the 4Runner but better, which he likes a whole lot. Could be that the entry jump up for him is about a foot and half lower, though...

wesintl
04-17-2009, 04:32 PM
just take the truck into account.

why? anyone can do 90 down vail pass and that's where you need this. Otherwise I'd just put on some blanks

Crash
04-17-2009, 04:49 PM
Bart a "Luxo Road King"? I have yet to see an icon yet that matches the chortle freshly emanated from my chortle area. Ask any 100 owner about the MUCH better ride it provides over the 80 series. 80s are has beens. Unbelievably good in stock form plus carpeting in the cargo area so they have that going for them but old school. Thanks for the smile, Dave. As for dogs making the leap of faith? Nell and Pearl have learned how to assume the position of paws on the tailgate all by themselves and then getting a boost up for safe entry into the LRK. They like how that sounds...LRK.
Uncle Ben, may I suggest some cryo treatment for that burning sensation? That should outta get it! Or, buy some mini parts and make the darkside happy.

DaveInDenver
04-17-2009, 06:26 PM
Bart a "Luxo Road King"?
Oh hell yeah, Bart rides reeeeaaallll nice indeed.

Rock Dog
04-17-2009, 11:09 PM
The lure of the DARKSIDE...
I love my 80, but my squeaky 4runner is just plain fun to wheel...
Heck Greg and Chili are both back for round 2 of there mini's..
I watch the mini's kick ass on most trails, and they are cheaper to fix than a 40 when they break...

Don't under estimate the power of the DARKSIDE......
and with Marlin along "FEAR THE TURTLE".....