Drilled Brake Rotors

[tuna boy]

Brian, did you have a hard time breaking through the glaze on the rotors. Did you use any coolant? The only problem is can you resharpen the step drill? Did you use a punch mark to start your drill. Neat old drill press.

 

[brianinpa]

tuna » Wed Jun 11, 2014 8:46 am[/url]":2tki82k4]
Brian, did you have a hard time breaking through the glaze on the rotors. Did you use any coolant? The only problem is can you resharpen the step drill? Did you use a punch mark to start your drill. Neat old drill press.

Glaze - no problem breaking through it, but that rotor didn't have much of a glaze on it.

Coolant - none used on this test because each hole only took about 15 seconds to drill and I wanted to see just what it would take to drill through the rotor.

Punch - none used on this test because I was just making holes; however, the step bit did not wander at all from the sharpie marker point that I had marked either, but when I am drilling the real rotor for my 1100, I will be using a center punch to mark the holes and prevent any cases of "Oops!"

Another nice thing about those bits is HF sells them really cheap. $5.99 each :mrgreen:
https://www.harborfreight.com/1-4-q...r-inch-high-speed-steel-step-drill-44460.html

 

[charles franz]

I resharpen mine, put the shank in the vise, Then use the angle grinder to follow the clearance angle, If you mess up grind a little deeper!!

 

[dan filipi]

Am I the only one nervous about drilling a rotor?
Seems to me taking metal away weakens the structure and throws it out of balance.
Gives me chills what could happen if a disk were to fracture at speed during a panic stop.
I've never heard of this happening but the possibility is there isn't it?

 

[Ansimp]

dan filipi » Thu Jun 12, 2014 1:19 am[/url]":3ck9g2eg]
Am I the only one nervous about drilling a rotor?
Seems to me taking metal away weakens the structure and throws it out of balance.
Gives me chills what could happen if a disk were to fracture at speed during a panic stop.
I've never heard of this happening but the possibility is there isn't it?

This has been a modification done for years Dan with out any real problems. I am almost sure that we could use cb900 discs on the Goldwings as some are identical and others were drilled, just haven't checked if the drilled ones are the same size.

 

[brianinpa]

As long as the rotor is drilled evenly, it shouldn't affect the balancing. As far as weakening the strucker goes, likke Tony mentions, it's been done for years and is even a stock item now.

 

[dan filipi]

Yeah I realize rotors come OEM drilled now but that's under controlled machining and hardened for the design.

Would you drill the rotors on your car?

To each their own, I won't be doing mine for a slight improvement.

 

[slabghost]

The only real issue I've read about drilling rotors is that if the holes are 100% even they can develop a harmonic vibration so they are drilled with at least one hole a little offset.

 

[brianinpa]

dan filipi » Wed Jun 11, 2014 4:26 pm[/url]":2npinpls]
Yeah I realize rotors come OEM drilled now but that's under controlled machining and hardened for the design.

Would you drill the rotors on your car?

To each their own, I won't be doing mine for a slight improvement.

I'lve been saying all along that the only reason I am considering it is because I have an extra set of rotors. I am taking the set that is the best and putting those off to the side and drilling the rotors that are the worst. The worst thing that I could do is scrap a pair of worn out rotors... No loss as far as I'm concerned.

 

[joedrum]

brians smart ... im really floored it drilling so easy for you ...wonder what the gain is ...seems to be a more bling thing on oldwing builds than anything else ....but im really interested in your assessment on it when you try it

 

[brianinpa]

joedrum » Wed Jun 11, 2014 6:10 pm[/url]":3qet5b8p]
brians smart ... im really floored it drilling so easy for you ...wonder what the gain is ...seems to be a more bling thing on oldwing builds than anything else ....but im really interested in your assessment on it when you try it

Better pack a lunch Joe cause it will be a while until I drill the real deal. Too many miles to ride now and too much to do to the 1200... again. :swoon:

 

[joedrum]

ok im packing .... oh you said lunch ... wrong packing ...hmmm well maybe not .... :0fftopic:

 

[Ansimp]

Having drilled rotors improves cooling ( heat exchange) and this improves braking performance also makes wet braking quicker!!

 

[Steve83]

Yup!

 

[ianstaley]

Personal opinion here and not a lot of science, to drill or not to drill. I am leaning a bit towards the drill side of the argument. I use drilled front and rear discs on my cars, I have a Toyota Supra MK3 I bought many years ago new. They are vented discs anyway but I believe that they promote better braking, reduce heat and in the wet clean quicker. I also have a MB ML270 diesel also with std vented discs but replaced with drilled discs too. Again I feel that they offer superior stopping (2 ton car) less fade due to heat reduction. On the Wing, now here we get to it, as I understand the GL1000 to 1200 have very similar brakes, I also know that from experience they can suffer from brake fade (possibly the pad material) especially from high speed hard stops. In comparison to a modern brake set up I do think that they are really 30 years old! I am seriously considering a secondary slave cylinder set up which should improve the grab, then it comes down to the discs. I have seen over here in the UK some after market discs that drilled in a sweeping pattern possibly of better material (steel) and floating which should I say should improve fast stop braking, problem is they are about £200 each which is quite hefty and of course the question will they fit? see bellow



They are EBC so come from a reputable supplier and I would opt for their pads too.

Just my 2pence worth :wave:

 

[brianinpa]

The biggest reason I have been considering this is that I know that most of the braking I do is with the front brake. Sure I use the rear brake when I come to a stop, but if I have my feet on the highway pegs and want to slow down a bit, I just use the front brakes. I want to get just a little more...

After looking at the rotor on the 1200, that is what got me to thinking about it: those are slotted and the front only braking seems to be a little better than the 1100 and remember the 1200 has the linked brakes where my 1100 doesn't.

 

[Ansimp]

I have been searching for drilled replacements and the closest I can find are some ebc ones like Ian mentioned except I am worried that the pro lites will not be as in the photo. The ones that they do show to fit the Rats Nest have slots around the inside edge that appear to assist with performance..
I like the 1200 slotted rotors and I am sure that they are an improvement over the 1100 ones but I am not sure that they would fit the Comstars and the callipers..

 

[joedrum]

i dont think they do

 

[brianinpa]

When I get back from my trip to North Carolina next month, that is something I will be finding out because the one of the PO of the 1200 mounted them on the wrong sides and that is something that is getting corrected.

 

[Joep]

Brian what about finding a used junk factory drilled rotor to use fir template? ...