GSXR calliper upgrade      



Motivation:

Although many feel that the stock GS front brake is perfectly adequate, there are a number of reasons why one may wish to upgrade the calliper. I cannot reliably attest to an improvement in performance as my original GS calliper was completely shot, but in general a four piston fixed calliper is superior to the OE two piston sliding calliper due to:

Lower effort at the lever for the same braking effect
Better 'feel' at the lever
More even pad wear
Looks beefier!

Also, these particular Nissin callipers seem plentiful (and therefore cheap!) on eBay as they were used on the earlier Suzuki GSXR, Bandit 1200 and RF900 models and maybe some others (TL1000?).

This mod has been done before here: http://www.bikepower.net/gs500e-power/gs500e-power.htm

My mod is essentially the same, but I feel the bracket design and placement is a bit more elegant. So Here's how it's done:

In order to make this work:



You need to make a bracket like this:



I used 6mm mild steel. This is the maximum thickness that will fit in between the fork leg and the brake disc. It is also the thickness of the standard GS calliper bracket. I would personally avoid using aluminium as some of the bolt holes are rather close to the edge of the bracket and I don't think you want to take chances with your front brake!

I tapped all four holes with an M10 tap with standard pitch, although you could use a finer pitch thread as on the OE bolts if you're worried about the strength of the threads.

I spent a while playing with the design to minimize the area of the bracket while maximising the swept area of the brake pads. I think I reached pretty much the optimum solution.

It's worth pointing out that apart from a couple of places where the bracket mates with the calliper, the exterior shape is entirely arbitrary, so you can change it to make it prettier if you like, just be sure to keep the holes in the same place.

The easiest way to make this is to give the Autocad file to someone with a CNC machine, so here is the DWG file that I used to make my own bracket (for the princely sum of 15 English pounds!).

http://www.nottingham.ac.uk/~ppzdrf/pics/GS/GSXRcaliper/%20GS_brake_bracket_4.dwg

When you have the bracket, there are a couple more things you need to do. Firstly, you must drill out the threads on the holes in the calliper and file a small notch in the bracket near the top left bracket hole (see red circle in picture below) to accommodate a small protrusion of the calliper.



I used a couple of thin (~1mm) washers (see green circle in picture above) to adjust the horizontal offset of the calliper so that it is centred on the disc.
Then you just need 4 bolts of the correct length (I bought M10x30 high tensile steel cap screws but I had to grind them down a little), bolt on, hook up the brake line, bleed the brake and away you go.

I did not need to change the brake line, but I have a braided hose which is not necessarily the same length as the stock hose, so I can't say for sure whether the standard one would fit, but I'd guess that it'd be OK.

I used the standard GS master cylinder (1/2" bore). It feels fine to me.

When you're all done you can stand back and enjoy your handywork before going out and enjoying your enhanced power and feel (of the brake, of course).



I hope this is helpful. If enough people are interested, maybe some crafty entrepreneur can make a few quid by running off a big batch of the brackets. I'll waive my right to commission for the bracket design in the name of good will to all men (and women!).

If I've missed anything obvious let me know. 

Dave Fowler

Nice job that Dave  I am sure there there will be a demand for the part. I know it will increase costs but have you considered making it in Stainless, say EN24 then finished with a nice mirror polish? It would look a lot better than Mild and increase its desirability.

awesome. 

How about a write up for the rear?  I feel my rear just doesn't cut it anymore.

Wow. Good work. And that's a really good-looking bike, by the by.

Quote from: NWDave on May 25, 2006, 10:35:28 AM
How about a write up for the rear?  I feel my rear just doesn't cut it anymore.

.........

Quote from: 3imo on May 25, 2006, 10:56:17 AM

Quote from: NWDave on May 25, 2006, 10:35:28 AM
How about a write up for the rear?  I feel my rear just doesn't cut it anymore.

.........

I'm serious, call me stupid but for longer braking (IE I know have to stop or scrubing some speed after opening it up I always use the rear, even when coming to stop.. not to say I'm afraid of the front or anything, I mean I use it when I really have to slow down, but it lets me keep my hand on the throttle if I need to speed up and out of the way of something or bliping the throttle for downshifts.

Hi,

Firstly, I did consider making the bracket in stainless steel, it would cost 1.5-2 times the price. I did mine in cheap mild steel to check if the dimensions were just right, then I decided just to paint it and stick with it, maybe I'll get one done in stainless, or maybe titanium...that would be cool - pointless, but cool!

As for upgrading the rear brake, I was under the impression that the limiting factor with rear brake performance was the traction of the rear wheel as the more you brake, the less weight is on the rear wheel. besides, almost all rear brake callipers are 2 opposed piston types, so I'm not sure what you would upgrade to. However, those little gold rear callipers on modern GSXRs look really cool compared to our bulky black items and the bracket would be quite simple, so if I get bored, I might give it a shot!

Thanks for the compliments.

Dave

Just some FYI, the '04+ bikes get a 4-piston front caliper you could probably just bolt up to the pre-'04 bikes.

I was just searcbing to see if any other calipers of this sort would bolt straight-up, but I'm not finding anything.  If anyone knows of anything, speak-up!

Also, if you are considering this mod with the GSXR/Bandit/RF caliper, a 6-piston Hayabusa caliper will bolt to the same pattern.  Totally overkill, but it would look really cool!  You may want to get a larger bore master cylinder for the increased fluid volume though...

If I could throw in 120k miles of GS500 riding experience including five trips to the Adirondak and Smoky mountains to "play" with the big boys, I'd say the GS500 front brakes could definetly use some upgrading but the rears are adequate stock and even quite good with the change to the HH pads.  There is a very noticeable increase in stopping power with the HH pads and any more on the rear could be hazardous to your health.  The rear EBC HH pads used on the GS500 are the same ones used on the Busa and some Gixxer and other Suzi models.  If you look around you will see the GS has a larger dia rear rotor than most of the higher performance bike do providing greater rear stopping power on the rear of the GS since the GS single disc front brakes don't unload the rear wheel as badly as the more powerful front brakes do on the Busa and Gixxer models. 

The GS500 front brakes with organic pads however are not really up to the job of very spirited riding in the mountains.  All my trips to the mountains were done with EBC organic pads and resulted in my turning the front rotor blue a couple of times.  One of those blue rotor experiences resulted in total front brake fade out at the bottom of the mountain with loss of front brake.  I have since gone to EBC HH pads front and rear and think these would be up to the job, but a better front caliper like Dave added would certainly be helpful.  What is really needed for max front brakes is twin brakes and the resulting greater pad area to help keep your front brakes cooler under hard riding.

Quote from: AlphaFire X5 on May 26, 2006, 01:47:11 AM
Just some FYI, the '04+ bikes get a 4-piston front caliper you could probably just bolt up to the pre-'04 bikes.

Alpha, have you actually seen a GS500F with a 4 pot front caliper?  The early literature for the 04 F model indicated they would have 4 pot front calipers but I've never seen them.  The parts fiches for the K4-K6 models show the same 2 piston pin slider front calipers used on 97 and later GS's.

http://images.powersportsnetwork.com/fiche/images/Suzuki/2004/Motorcycles/7247_47A.gif

Quote from: gsJack on November 18, 2006, 08:29:12 AM

Quote from: AlphaFire X5 on May 26, 2006, 01:47:11 AM
Just some FYI, the '04+ bikes get a 4-piston front caliper you could probably just bolt up to the pre-'04 bikes.

Alpha, have you actually seen a GS500F with a 4 pot front caliper?  The early literature for the 04 F model indicated they would have 4 pot front calipers but I've never seen them.  The parts fiches for the K4-K6 models show the same 2 piston pin slider front calipers used on 97 and later GS's.

http://images.powersportsnetwork.com/fiche/images/Suzuki/2004/Motorcycles/7247_47A.gif

My statement back then was based on that literature and what was on the Suzuki website. I had my brake pads off (checking the wear) and I noticed my front caliper was a 2-pot caliper, not the 4-pot as advertised on the Suzuki website.

anyone still have this autocad file?

Hi,

If anyone wants me to email them the autocad file, just email me at 'bobdave87 at hotmail dot com'. Sorry the link don't work anymore.

Dave