Suzuki GT500 lighter rotors?

moth_boy · Post by **moth_boy** » Fri Dec 04, 2009 7:43 am

Hi!
Looking for lighter rotors for the Suzuki GT500 front end. Anyone know if there are any from any other bikes and/or suppliers that will work with the stock mounts? Or the stock mounts flipped around to the rear? I'd be ok with using different calipers, especially two-pots if I can find some that will fit without too involved fab.

I've got a '69 suzuki T500 that the previous owner converted to a front disc brake using a GT500 front end. I was hoping to improve front braking and aesthetics (IMHO) of my cafe project by going to a double disc. So I got a set of GT550 sliders with caliper mounts on both sides that I think will work. But now I'm worried that two heavy discs on the front is going to make it handle like crap. I plan on fabbing up a steering dampner of some sort, and using steel braided brake lines. I know i can drill the rotors, but I'm not sure how much weight that's really going to save me.

I've seen kits for the gs750 that look like they use similar hardware/mounting points.

Has anyone done a conversion like this using more modern brake rotors?
Thanks!
JD

Tom Garcia · Post by **Tom Garcia** » Fri Dec 04, 2009 9:33 am

If the hub pattern is the same, a GS1100 rotor bolts up to a GT250 hub... They are thinner and lighter...

tz375 · Post by **tz375** » Fri Dec 04, 2009 11:09 am

Tom, that is so clean. I need to pull mine apart and start all over again I think.

That's a GT750 hub, replated spokes, Honda CBR600F3? rotors and SV650 calipers and aftermarket rims I stole from one of my TZ350 projects. The picture was taken when I was working out the adapter brackets and the OEM hoses were still on.

I found a supplier on ebay who made up a pair of braided stainless lines with black covers to my custom lengths for less than $60

CJF · Post by **CJF** » Fri Dec 04, 2009 9:01 pm

The GT250 and GT500 use the same hub, so the bolts should line up fine with the GS1100 disk. The other thing that you would need to check is the overall diameter of the disk and the offset. The thickness shouldn't be an issue if using the stock GT500 caliper, but if using something else, you will want to make sure the caliper will allow for the thickness of the disk. Also, if you go with a non GT500 caliper, you will need an adapter mounting plate unless the bolt spacing is the same and the angles are the same. A lot to think about.

durgam · Post by **durgam** » Sun Dec 13, 2009 10:50 am

Im looking into a custom plate for mounting a GSXR 600 caliper to my GT550. The problem with modern 4 pots is, that they are too deep on the inside and hit the spokes. So, I drew up a rotor spacer, to bring the rotor closer to the fork tubes. I may be able to move the rotor out enough or I may not. Its mostly in my head at the present time.

Tom...did you have the OD on that GS rotor turned down? And why?

Tom Garcia · Post by **Tom Garcia** » Sun Dec 13, 2009 10:57 am

durgam wrote: Tom...did you have the OD on that GS rotor turned down? And why?

The forks and front caliper are from a Honda CMX250 Rebel... I turned down the OD of GS1100 disc and everything was "bolt up" including the stock GT front hub bearings and spacers....

Tom

Barry S. · Post by **Barry S.** » Sun Dec 13, 2009 7:12 pm

I put a GS rotor on a '77GT 380, fit right on, I have the same rotors on my Buffalo, they are smaller in diameter than the stock GT750 but they work even though the brake pads don't touch the rotor at the top. Suzuki made a slotted rotor the same diameter as a GT750 but it was only a one brake setup, so there's not a mirror image one for the other side, I think it was a GS650, I have one in the shop.

moth_boy · Post by **moth_boy** » Sun Dec 13, 2009 8:25 pm

Thanks for all the info!
Those are some good looking front end setups that look like they can stop a lightish bike like the t500 quick.
I'd looked at some gs 1100 rotors on ebay, but the seller said they had a different offset than the solid steel ones on the t500. But he was probably mistaken. He also said they were a little smaller in diameter. But If yours slot into the stock caliper it's worth a shot! I'd think as long as the caliper piston was pressing on the rotor, it wouldn't matter if the pads were off it a little.
Thanks,
JD

Buffalo-guy · Post by **Buffalo-guy** » Sun Dec 13, 2009 10:31 pm

To add to Barry's comment, I have used those very brake rotors from a single disc GS bike. On my former hotrod buffalo, those two rotors, and a raised shoulder alloy rim FROM A Yam XS650, saved close to 5 pounds of unnecessary weight, and the material the later rotors are made of gave a noticeable improvement in braking power. The venting slots were not symetric from side to side, but not too many people noticed. The pluses far outwayed the minuses. IMHO. Cheers.
Fred