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Resurface GS Brake Disc Rotors

srsupertrap

srsupertrap

Forum Sage
Past Site Supporter
You probably already know . . .

Instead of replacing your "wavey" out-of-spec brake disc rotors you may consider having the rotors resurfaced on a rotary surface grinder. This was desirable option for me since I had already cross drilled all three of my brake disc rotors. This resurfacing cannot be performed on newer style floating brake disc rotors. I found this service on Ebay, See Seller: smw70ss (Portland Engine Rebuilders?). I believe they have maintained a 100% Positive feedback to date.


When I received the resurfaced rotor, I checked the flatness by placing the resurfaced rotor on the Inspection surface plate and sweeping a dial indicator over the entire surface. The flatness was within tenths. I checked the parallelism with a micrometer with similar results. Unfortunately I had the service performed last year and the price has been raised to $49.99.
 
Good info, Thanks.

Ive warped 3 sets and had them replaced. I guess if they dont get to thin resurface is an option.

Have we seen pics of your Bikes yet ?
 
GS1000A.jpg
 
Love the blue/gold wheel combination, very classy.
And thanks for the resurfacing tip.


Sent from my iPhone
 
Great job!

Great job!

I really like it when people go with modifications that look period. Very tasteful! Please post more pictures of the beast.:-D
 
Never thought about the surface grinder for gs rotors. I've got 6 warped disks in the garage and a flywheel grinder in the shop.....I'll let you know how it turns out (pun intended)!
 
Did you ever ask him how much material is actually removed?
For my '79 1000E the factory manual states only .02 can be lost (front rotors), then the service limit is reached. Normal wear usually would remove a good .01 That would leave only .01 that could be used to make it flat again or you go past the limit.
I'm no brake expert and I've always wondered if you went beyond the service limit, how would that effect the braking? I'm not talking about removing unlimited amounts of material but what if you needed to remove .04 to make it flat again? Could the piston go too far out and cause a problem? Anything else you can think of regarding a too thin rotor? Would the new re-surfaced rotor become warped again too easily/soon?
 
KEITH KRAUSE said:
Did you ever ask him how much material is actually removed?
For my '79 1000E the factory manual states only .02 can be lost (front rotors), then the service limit is reached. Normal wear usually would remove a good .01 That would leave only .01 that could be used to make it flat again or you go past the limit.
I'm no brake expert and I've always wondered if you went beyond the service limit, how would that effect the braking? I'm not talking about removing unlimited amounts of material but what if you needed to remove .04 to make it flat again? Could the piston go too far out and cause a problem? Anything else you can think of regarding a too thin rotor? Would the new re-surfaced rotor become warped again too easily/soon?
Click to expand...

I have no idea about the possibility of a slightly too thin rotor being weakened and breaking or warping early.

But I have a solution to you for the piston traveling too far:
Just replace the brake pads with at least .02 inches worth of friction material still on them. :eek:
 
KEITH KRAUSE said:
Did you ever ask him how much material is actually removed?
For my '79 1000E the factory manual states only .02 can be lost (front rotors), then the service limit is reached. Normal wear usually would remove a good .01 That would leave only .01 that could be used to make it flat again or you go past the limit.
I'm no brake expert and I've always wondered if you went beyond the service limit, how would that effect the braking? I'm not talking about removing unlimited amounts of material but what if you needed to remove .04 to make it flat again? Could the piston go too far out and cause a problem? Anything else you can think of regarding a too thin rotor? Would the new re-surfaced rotor become warped again too easily/soon?
Click to expand...

These were my thoughts too....the resurfaced rotor would look cosmetically perfect, but have very little (depending on amount taken off) service life left. Since the same rotors were used for a number years/models (in my case), good ones come up for sale fairly often at an avg price of $25/per, which is half what it will cost to machine warped ones. Car rotors are turned to achieve a cost saving over buying new, but for bikes it makes less sense (IMHO) with the costs involved.:-k
Tony.
 
When the rotors have gone bad on my truck and Suburban I've just bought new ones. The new ones for a heavy duty 3/4 ton Chev pickup only cost about $38, and it costs nearly that much to resurface the old ones.
 
srsupertrap said:
You probably already know . . .

Instead of replacing your "wavey" out-of-spec brake disc rotors you may consider having the rotors resurfaced on a rotary surface grinder. This was desirable option for me since I had already cross drilled all three of my brake disc rotors. This resurfacing cannot be performed on newer style floating brake disc rotors. I found this service on Ebay, See Seller: smw70ss (Portland Engine Rebuilders?). I believe they have maintained a 100% Positive feedback to date.


When I received the resurfaced rotor, I checked the flatness by placing the resurfaced rotor on the Inspection surface plate and sweeping a dial indicator over the entire surface. The flatness was within tenths. I checked the parallelism with a micrometer with similar results. Unfortunately I had the service performed last year and the price has been raised to $49.99.
Click to expand...
So you had warped rotor(s) had this done, and your brakes work fine? No issues at all such as more lever play or a little loss of stopping power?
Sorry, but what do you mean the flatness is within tenths?
Did you measure your rotor thickness when they came back? This could give you an idea how much they removed. Your factory new thickness is in your manual.
I too have invested in my rotors by drilling them and powdercoating the centers and would be interested in this work if there's no issues related to taking off too much material to get them flat.
 
Interesting this thread popped up today. I have a 1982 Suzuki GS 1100 L (GLZ). The front brake pads are worn so I went to a shop today to buy new pads. Given that I now replace the rotors on my cars when I replace the pads (super cheap), I asked for same. WOW! The rotors are $220 each, I later found them for $145/each on JCWhitney.....still, that is a lot of cash. I have no reason to think they are warped, and there does not appear to be any serious grooving. I was just thinking of using some brake cleaner to clean them really well and then hitting them with some really fine sandpaper. Any thoughts. Obviously front brakes are vital, but I just cannot justify spending $500 on new rotors if I can salvage the old ones. Any gouge/experience in this area is greatly appreciated.

Thanks,
Mike
 
If you have a micrometer or vernier calipers measure the thickness to see if they are within the manual's service limits....if they are, and not warped (no 'pulsing' at the lever, when brake is applied) re-use them.....if not, get a set on ebay.... they are the same slotted rotors used on the E, and other bikes, I think. Be sure to ask about thickness/flatness before pulling the trigger though. New pads feel weak for the first few miles on old rotors, before bedding in.
Tony.
 
KEITH KRAUSE said:
So you had warped rotor(s) had this done, and your brakes work fine? No issues at all such as more lever play or a little loss of stopping power?
Sorry, but what do you mean the flatness is within tenths?
Did you measure your rotor thickness when they came back? This could give you an idea how much they removed. Your factory new thickness is in your manual.
I too have invested in my rotors by drilling them and powdercoating the centers and would be interested in this work if there's no issues related to taking off too much material to get them flat.
Click to expand...

I did the rear disc in 2006 and when I received it I measured it with my Mituyo digital caliper. It was well within Suzuki's upper tolerance specification although I don't recall the exact measurement anymore. The Portland Shop took off the bear minimum of material which probably explains his 100% rating; he appears to have his process down. I have experienced no negative brake issues such as more lever play or any loss of stopping power.

Ten-Thousandths (tenths) is .0001" Flatness is a measure to itself. Some people mistake Parrallelism for flatness. I measured the flatness by placing the resurfaced rotor on three 1-2-3 Blocks placed on a surface plate and sweept the entire bottom surface with a dial indicator. The worst run out was .0007" and I measured it several times and got repeatable results.

The resurfacing is probably a good choice for you because your reasons are the same as mine were.
 
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