Do I need to spend $250 on a brake disk? 1983 GS850GL

[Guest]

Hi all,

I've spent the last hour trying to figure out what parts I need for replacing my grooved FR brake disk and all I could come up with that looked legit is an EBC Pro-Lite Brake Rotor - MD3014RS

​Does anyone know if there are any other options out there?

 

[gustovh]

I have discs, should be the same size as my 80L. Do you need them both?

V

 

[rphillips]

How deep are the grooves, a machine shop can easily slick them back up.

 

[bwringer]

Buy used brake rotors from fleaBay. Most bikes were scrapped and parted out long before the rotors wore out, so there are plenty out there. Pretty much every GS from 1980-83 used the same rotors.

You can cross-reference the part numbers to many GS models.
DISK, FRONT BRAKE RH 59211-45250
DISK, FRONT BRAKE LH 59221-45250

This list might be helpful:
https://www.partzilla.com/product/suzuki/59211-45250​
Some of these are models with only one rotor


Some will come with a "free" front wheel attached; sometimes you can convince the seller to remove the rotors (and scrap or sell the front wheel you don't need) so you don't have to pay to ship the whole thing.

There's also the whole "big brake" or "twin pot" conversion, where you replace the rotors and calipers with more modern Honda bits using adapters for the calipers, and rotors that bolt straight on. Most of these were not done on GL models, which have different mounting points on the forks, but it might be worth investigation.

Honestly, stock 1980+ GS brakes that have been competently rebuilt and are wearing stainless braided lines and quality major brand, modern brake pads are actually pretty damn good. I'm a fan of the EBC red pads, personally.

 

[LAB3]

Don't know how many times I've heard people say "You can't turn motorcycle rotors on a brake lathe!" Fair enough but that doesn't mean they can't be turned on another type of lathe! Small machine shops have all but disappeared but they are still out there. There's also places to have them ground, one guy in Michigan does them for $60 ea.

 

[rphillips]

The brake shop wouldn't turn mine, never mentioned the machine wouldn't do it, they said they wouldn't because the rotors were below spec. Machine shop just turned them and never mentioned anything about specs. All was good.

 

[salty_monk]

Twinpot mod details in my signature. You'd need to cut your own brackets (Out of flat 3/16" steel) but the rest of the kit will work. I have a picture from a guy who did similar. He used the original as a template & just extended and moved one of the holes as necessary.

 

[Grimly]

The brake shop wouldn't turn mine, never mentioned the machine wouldn't do it, they said they wouldn't because the rotors were below spec. Machine shop just turned them and never mentioned anything about specs. All was good.

Given that there's often a minimum thickness stamped on the disc, if the second shop just merrily ignored that, they should be kicked up the ass.

 

[rphillips]

second shop was just a machine shop, not a brake or mechanic shop. Heck I was tickled to death. All good.

 

[MaurieG]

second shop was just a machine shop, not a brake or mechanic shop. Heck I was tickled to death. All good.

If the rotors were under spec before you started, they're even more so now! What you gonna do if they fracture when you're doing 80? You'll be tickled then!

 

[rphillips]

I'd probably do the same as I would if one of the forks broke off at 80mph.... but that didn't happen either... All I know is they were on my KZ1300 and I rode it several thousand more miles then sold the bike and all was still good.... Not only did I run rotors a little under spec, I also change my oil every 5000 mi. instead of the 3000 mi that the oil co.'s recommend and run my tires until they're worn out instead of replacing them when they get to the wear bars.... Everybody do what works for themselves and all should be good.

 

[melchiro]

Send your rotor disc to,
https://truedisk.net

They will make it look & perform new again.

 

[bwringer]

Send your rotor disc to,
https://truedisk.net

They will make it look & perform new again.

Yup, that's an option in many cases, but they are still removing material, and will not go below the minimum thickness. Motorcycle rotors have very, very little extra thickness, so measure in several spots before deciding to have them ground.