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Calipers that bolt on to GT750/550 forks.
Posted: Sun Jul 10, 2016 1:49 pm
by Ebayru
I'd like to upgrade to twin rotors on my GT550. I have the left fork with the mounts. I've scoured all the past posts on the subject, but would appreciate if anyone with actual knowledge of the calipers from different bikes that will bolt on to my bike without bracket or disk modification would please list them.
Thanks!!
Re: Calipers that bolt on to GT750/550 forks.
Posted: Wed Jul 13, 2016 3:20 am
by Alan H
GS1000 twin piston calipers fit straight on. Use a Bandit 1200 master cylinder.
That's the setup on my 550.
Details here
viewtopic.php?f=2&t=11247" onclick="window.open(this.href);return false;
Re: Calipers that bolt on to GT750/550 forks.
Posted: Wed Jul 13, 2016 5:43 am
by jabcb
That’s interesting. Could you be a bit more specific about which GS1000 caliper you are referring to?
Re: Calipers that bolt on to GT750/550 forks.
Posted: Wed Jul 13, 2016 7:33 am
by Ebayru
Thank you for your reply. All the GS1000 calipers I've been able to find on eBay appear to be single piston. It also seems the GS1000 calipers are shared with the GS850s and, perhaps GS750s. Anyone with more info about this?
Re: Calipers that bolt on to GT750/550 forks.
Posted: Wed Jul 13, 2016 11:46 am
by Alan H
jabcb wrote:That’s interesting. Could you be a bit more specific about which GS1000 caliper you are referring to?
I just got them off eBay as gs1000 calipers.
Not sure which one, if you have a look at the link above, someone may id the calipers.
Re: Calipers that bolt on to GT750/550 forks.
Posted: Tue Aug 02, 2016 7:26 am
by Ebayru
I purchased calipers from ebay supposedly for the GS1000 and they do not fit. Now I have to resell them and I still don't know what to do.
Re: Calipers that bolt on to GT750/550 forks.
Posted: Tue Aug 02, 2016 10:48 am
by jabcb
Alan H wrote:jabcb wrote:That’s interesting. Could you be a bit more specific about which GS1000 caliper you are referring to?
I just got them off eBay as gs1000 calipers.
Not sure which one, if you have a look at the link above, someone may id the calipers.
Could you post a closeup pic of the calipers?
What shape are the pads (round, etc.)?
Re: Calipers that bolt on to GT750/550 forks.
Posted: Tue Aug 02, 2016 11:58 am
by Alan H
Here's a pic taken during the build up, They were bought as 'GS750/550/1000 calipers' and I wrote and asked the guy to measure the mounting hole centres. Simple!
The pads are round and the calipers are twin piston.

Re: Calipers that bolt on to GT750/550 forks.
Posted: Tue Aug 02, 2016 8:03 pm
by jabcb
Took a look at the EBC catalog.
The two strokes use pad FA55.
The four strokes transitioned from round pads to “rectangular” pads around 1980.
The four strokes with round pads use pad FA35 or FA38.
The FA35, FA38 & FA55 pads have approximately the same OD.
Your calipers look a lot like the ones on a 79 GS750.
Re: Calipers that bolt on to GT750/550 forks.
Posted: Fri Aug 05, 2016 12:46 am
by titan performance
Did we get some definitive info on this topic? I plan to fit a GT750 front end on my T500, and plan to pep up the brakes. The calipers on the 550 above look single piston to me......
I'm sure I read somewhere about using some SV650 components, but I don't recall the details.
Re: Calipers that bolt on to GT750/550 forks.
Posted: Fri Aug 05, 2016 5:29 pm
by old racer
I am led to believe that the gs1000 78-79 model calipers fit straight on.
This type Not round pads.
http://www.ebay.co.uk/itm/SUZUKI-GS1000 ... Swr41XH32I" onclick="window.open(this.href);return false;
Re: Calipers that bolt on to GT750/550 forks.
Posted: Sun Aug 07, 2016 10:53 am
by Ebayru
Alan H wrote:Here's a pic taken during the build up, They were bought as 'GS750/550/1000 calipers' and I wrote and asked the guy to measure the mounting hole centres. Simple!
The pads are round and the calipers are twin piston.

It looks like there is only the top bolt holding the caliper to the fork. Am I correct?
I measure the bolt holes on the GT750 forks to be 73 mm center to center. The GS 1000 calipers bolt hole spacing is about 3 mm wider plus the calipers are too wide to clear the fender struts. I want to keep the bike as close to stock looking as possible so I don't want to modify the fender.
I finally found a set of GT750 calipers on ebay and purchased them. There is another left caliper on ebay right now except it doesn't show up in searches because it's listed incorrectly.
Re: Calipers that bolt on to GT750/550 forks.
Posted: Sun Aug 07, 2016 11:19 am
by Alan H
That was taken during the build and it does appear to have only 1 bolt in, but the other went in perfectly as you can see here.

Re: Calipers that bolt on to GT750/550 forks.
Posted: Sun Aug 07, 2016 11:30 am
by Ebayru
Alan H wrote:That was taken during the build and it does appear to have only 1 bolt in, but the other went in perfectly as you can see here.

I suspect those calipers have two opposing pistons which makes them interfere with the standard spoked wheels which I have on my bike.
The GS 1000 calipers I had purchased were single piston with rectangular pads. They cleared he spokes, but not the fender struts and the hole spacing was too wide. They are definitely different from the ones on your bike.
Re: Calipers that bolt on to GT750/550 forks.
Posted: Tue Nov 22, 2016 6:14 pm
by Ebayru
I tried the GS850 calipers, but they are too wide fore and aft to mount without removing or modifying the fender struts. I finally found a decent left GT750 caliper on Ebay and used that. I thought I'd try the stock single caliper master cylinder first to see how it worked instead of installing the two caliper master cylinder that came with the GS caliper set. It works perfectly and I won't be changing it. The difference in stopping power with the dual disc setup is amazing. I'm pulling a sidecar on my GT550 and the upgrade was badly needed.