Rear caliper mounting locations

[E.Marquez]

The VTR1000F caliper is mounted above the rear axle and slightly forward


With the impending swing arm MOD I have coming up (900r brace) and the need to address the caliber bracket swing arm mount as part of that MOD.. I'm thinking about changing up the entire rear brake setup..
Performance? no not really I ask very little but feel and feedback from my rear brake. Just that if I have to source a caliper bracket (900r) and cut / re weld the bracket guide on the swing arm.. the opportunity to do something a little different is here.


The current crop of go fast bikes from all 3 big names use a top and forward mounted rear caliper..

WHY?

What advantage is that vs a lower and forward mount location?
I have what I "think" are some of the advantages from research, but of course there are just educated guesses...and Im more interested in the disadvantages.
ZX636

Triumph

ZRX1200

Many others.....as well.

Or put another way.. what are the disadvantages of the lower mounted rear brake?

I can see it taking more abuse from road debris.. or road conditioning chemicals if used in your area. Perhaps that in itself is the reason, damaged finishes, corroded sliders, seals damaged,,ect.
Unless it is designed to mount in the under the axle position, and has banjo fitting / bleeder on top, the caliper will need to be removed & rotated to bleed.. as thats only once a year maintenance task not really much of an issue for me.

HRC has used the under / forward mounted rear caliper



Thoughts?

[tony.mon]

Forward of axle= best mass centralisisation
Underslung= lower c of g.
Whyever not?

[E.Marquez]

Forward of axle= best mass centralisation
Underslung= lower c of g.
Whyever not?

Above or below, the caliper will be forward of the axle. so thats a wash I think.

And yes, below the axle intuitively makes sense that it would be better for lower CG

[Tweety]

I really can see no other reason, than for road debris/salts whatever... And potentially the bleed issue if you use a stock VTR/CBR caliper... I'd go for one meant for underslung mounting, with the bleed in the proper place, and be done with it...

[lloydie]

I'd like a under slung one for miss piggy but keep thinking it will get in the way when the bike is on paddock stands .

[gl_s_r]

Lloydie, I have an underslung one on mine and it doesn't get in the way of the stands I use..

Will add a picture tomorrow so you can see if you like?

[lloydie]

Yer but you have very fancy brackets there ! :-(

[gl_s_r]

I think it's a standard one if I remember.. know I changed it to fit the chain adjusters a little while ago but nothing special.

Been ages since I played with that bit of the bike but I'm sure it's nothing different and will check tomorrow.

[E.Marquez]

Lloydie, I have an underslung one on mine and it doesn't get in the way of the stands I use..

Will add a picture tomorrow so you can see if you like?

Heck yes.. please do post pics and ID any of the parts used (caliper, lines, ect)... I'm assuming you made the bracket.... if by chance you have that part in a digital CAD file that would be great as well.

Did you use a forward strut to manage mount rotation? or adapt the new mount to use the guide on the swing arm?

[gl_s_r]

Okay.. I'll add some pictures that hopefully explain the mod.



It is a standard bracket and it was cutaway to roughly the white line drawn on the spare I have held up to the swing arm... it just got rid of the original slot location for the original swing arm.





The caliper is then underslung ( as tweety said it will have the bleed niplle the wrong way ) and located via an aluminium ( or alumium for you there ) tube with a rose joint at each end. This is what stops the rotation of the caliper.




There is a triangular lug welded to the bottom of the swing arm ( which can be put there when you have the brace put on ) and through that just a clearance hole for a M8 nut and bolt. This can be drilled before or after welding

Hope this helps and is hopefully simple enough to copy with no special parts needed

Please excuse the rusty nuts and bolts as I put them in there while I measure up and get some more stainless ones

[lloydie]

I like the way the brake line hides the caliper brace :-)

[Jamoi]

Wow everything in that pic is beautiful! The underslung caliper is great, that was one of my fav features of my old YZF750.

[gl_s_r]

The rusty makeshift bolts aren't! They look really bad.

Waiting for Xmas to finish and then I'm off down the nut and bolt shop. I'll get yours when I'm there Jamie as got the large bits back and just about to send the smaller bits off now I know they can be done.

[tony.mon]

It even says "nissin" the right way up!

Now stop chewing your nails.

[lloydie]

Think glsr is also from grain only 3 fingers !! The others must be on the other hand