[kenmschwarz]

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Hi, took off the rear tire to replace, hard time getting the disc brake calipers off. Inspecting the rear brake rotor, looks scored and it has a "lip" at the end of the rotor, where it hasn't been worn down. Can the rotor be turned, and should it, or is a replacement in order. A new Galfer can be had for $169 :X. (I would rather spend it on rear shock rebuild)



thanks for any help

 

[corneo]

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I'm sure it can be turned. As long as it doesn't fall below the specs. (if it does fall below specs, some shops will cut them, some won't. You just have to ask)
On a item like that you can find them on ebay all the time. It's a part that age doesn't hurt and there usually cheap. This one, starting bid 9.99
[url]http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4502862803&category=35592[/url]

Or check your local junk yard.

Sometimes the grove that get cut in to the disc isn't that bad. Keep in mind that 80% of your stopping comes from the front wheel (that's why there is 2 disc.) and 20% from the back wheel.

Good luck

 

[Goldwinger1984]

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If you do happen to have it turned it would be done best while it is attached to the wheel, otherwise you could end up with some brake shake if it ends up being a few thousandths out of spec. Make certain that you torque the rotor to factory specs as well as this can also cause some distortion.

Vic

 

[Kyle]

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My advice is if your brakes are working fine and you're not going through a set of pucks every season....leave it alone! If it gets machined and its not turned properly it is done. If you buy used you're taking your chances. If you buy new...its big bucks. Of course if your rotor is absolutely positively worn out, those are your choices.

Just to give you an idea, my rotor has somewhere between 3-400,000klm on it and it does have a lip, but my pucks have normal wear.

Corneo said

Sometimes the grove that get cut in to the disc isn't that bad. Keep in mind that 80% of your stopping comes from the front wheel (that's why there is 2 disc.) and 20% from the back wheel.

This is a huge factor to remember if you do alot of riding in the mountains. Rely on your front brake and assist with the rear. I lost my brakes going down into the the Black Canyon of the Gunnison in Colorado. Just as I got to the bottom, my brake lever fell through the floor. My facts maybe a little sketchy butI believe it was about a 5 mile run at a 16 percent grade and I did it all wrong by riding my rear and assisting with the front. What do you expect from a boy from the prairies.:cheeky1:

 

[exavid]

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Sounds like gearing down on the downslopes would have been a good idea. I drive charter buses and a couple of rules of thumb we commonly use is that you should use the same gear (or lower) coming down a mountain that you used going up. Likewise you should go down at a similar speed as going up. So if you have to go up a long grade that requires a lower gear, coming down ought to be done in pretty much the same manner. I find my '86 can handle some pretty long down grades such as descent from Mount St. Helens and Mount Rainier easily in 4th using the brakes very little.

One of the problems nowadays is the lack of asbestos. Modern brake material just isn't as good. Heavy use causes fading which causes a driver or rider to use even more pressure which merely accellerates the fading. Pused far enough and you will run out of brakes before you run out of downgrade. Not much fun. On many mountain highways on U.S. Interstates you might have noticed the runaway truck escape chutes. I don't think I'd like to try one in a truck, much less a motorcycle. Sorry about being so long-winded but I've seen a couple accidents caused by brake failure so that's one of my personal bugaboos.

 

[englishted]

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You can turn the discs, but if there is a lip you really want to check that the worn part is within spec (I think 4mm for the gl1100) before deciding whether to turn or replace.

 

[Jason]

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Ted sums it up well. You can turn the discs because they are machined to be omni-directional, that is they will work regardless of the spin direction.

 

[Kyle]

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Sounds like gearing down on the downslopes would have been a good idea.

Exavid... I hear ya on the gearing down and wished my bike had an engine retard.

I also have ridden Mt.St.Helens, Mt.Ranier, and Bear Tooth,and that is Super Highway compared to the Black Canyon of the Gunnison. I wouldn't ski down that road!! I'm not sureif I got that bike out of first or second gear.....too fast with the constant switchbacks getting to the bottom of the canyon! Believe me..1st gear you'd blow your motor and 2nd was too fast. But afterwards...I did learn to break with the front and assist with the back. Another wild chunk of road is just outsideof Mexican Hat. It's not quite as steep as Gunnison, a couple of degrees of grade better but it is gravel and I only did the climb out. If you get a chance to get out that way, go have a looky see. By the way...I love your Washington/Oregon coast. Alot nicer than the California Coast line I figure.

Kyle

A woman drove me to drink.....and I didn't even thank her!

 

[corneo]

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I was talking to a friend of mine about this problem and he reminded me that we have never turned a cycle disc. The reason was because we never ran in to anything that bad. Sure there were groves in it, but we knew the new disc would wear themselves in to the groves and they would work fine. (hey we watch cost anytime we can)

The craziest thing we did was drill holes in to the disc (about 30 of them) and painted the disc. Which gave a really great look to it. (The paint was removed were the pads touch) The reason for the holes was to keep the disc cooler. If you think this was a stupid idea, look at racing disc.... they have about 50 holes in them and causes the disc to keep cool. Which may be a idea for anybody who does a lot of mountain driving. It didn't effect a balance problem with the disc and was cheaper than buying one already drilled.

That's one of my stupid moves in life that work out to my advantage. :gunhead:

 

[Shooter]

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This goes out to "corneo", I also drilled the three disc set-up on my 900 Custom. These were in the pre-Goldwing days,(mid 80's). After-all, all the new LTD's,GPZ's and GS's had them, so I figured my Honda was a little lagging. I left the holes un-chamfered, and this served to help keep the pads clean. Didn't give much thought to heat related brake-fade, but did notice an improvement in wet weather stopping. Seems that all those holes served to give the water some place to go.

As I recall, I put closer to 85, 1/4"holes in each disc. The money I saved by doing it myself paid for my drill-press.

Yeah, it looked really cool, but in hind sight, I have to wonder if it was really worth all the bother....

How hard is it going to be to live up to this GURU thing....:action:

 

[JDuggan]

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Shooter wrote:

This goes out to "corneo", I also drilled the three disc set-up on my 900 Custom. These were in the pre-Goldwing days,(mid 80's). After-all, all the new LTD's,GPZ's and GS's had them, so I figured my Honda was a little lagging. I left the holes un-chamfered, and this served to help keep the pads clean. Didn't give much thought to heat related brake-fade, but did notice an improvement in wet weather stopping. Seems that all those holes served to give the water some place to go.

As I recall, I put closer to 85, 1/4"holes in each disc. The money I saved by doing it myself paid for my drill-press.

Yeah, it looked really cool, but in hind sight, I have to wonder if it was really worth all the bother....

How hard is it going to be to live up to this GURU thing....:action:

Thats easy for you to say, but what about us poor mortals that aren't gurus! :action:

I was told the reason the holes in the brake discs have slight chamfers is to stop the pads wearing too fast.

 

[Goldwinger1984]

imported post

That chamfer around the hole does help with lessening pad wear, but, also helps reduce noise and vibration.

Vic