Brake Caliper Upgrade

[Jamoi]

Yep radial ,s are far better. I haven't even got braided hoses on mine and there just superb. However, the newer bikes have far better suspension, brakes forks as standard etc. They will always say in the mags to "Upgrade to better suspension and brakes" they want us to spend money. Remember went brakes discs weren't even drilled, we still went out in the wet but just "Clenched" more while braking

yes even though it was a long time ago, I still remember almost hitting the rear end of my brothers bike when my front solid disc brake on my Honda CB400four took time for the water to disperse before it worked
You just had to remember to calculate that into your stopping time
My excuse was, the bike was new to me and it was the first time I'd been out in the wet.

Chris.

You just reminded me of my first "big bike" Chris.

Honda CB550 77' vintage, it had been cafe racer'd & I couldn't afford new pads for the front caliper (with solid disc). So I removed the caliper completely 100mph never felt so darn fast

Can't believe the stuff I used to do on bikes, this was before I had a licence too

[Twitchy]

Thanks for the replies guys. Just to reiterate though it is only the hand controls I have got, so clutch m/c and lever, and brake radial m/c and lever, no calipers.

AMcQ, did what I think was a lot of digging yesterday and could not find any specs on the factory Honda radial m/c from that era (2005-06-07). I was hoping to find the piston diameter and stroke to compare to your list. Unsuccessful so far. But as it has 11/16 cast in, and adjacent to the '11/16' it has '4' (I will assume for the moment that the '11/16' is the piston diameter). There is a number obscured by the brake switch, which I haven't removed yet.

I can't remember where, but I did find a bloke who posted either here or SH forum regarding finding a setup for his motard that (obviously) radial and axial sizes are different. He reckons for 4 pot calipers use 14mm axial or 17-18mm radial, and for 6 pot calipers use 16mm axial or 18-19mm radial. Going on that comparison, the factory m/c for the Firestorm is 14mm, then an 11/16 (17mm) radial should provide similar hydraulic pressure on the pistons to the 14mm factory m/c. However the radial will most probably have a shorter stroke so may be more 'on-off' as noted by others.

(maybe I need to strip these and get the verniers out.....)

[Cadbury64]

My observations are a little different to some of the previous comments. I have fitted a complete set of CBR954 front brakes on my VTR, and have just installed a complete set of CBR600F4i brakes on my VFR800; both have stock "Nissin" branded pads and are well serviced.

The 954 brakes (using standard VTR hoses) have much more feel and no less power; I'd give these 10/10, they really feel fantastic. By comparison, the 600 brakes have plenty of power but feel wooden with very little lever travel (on braided lines). I'm going to fit some EBC HH pads to my VFR and see if that improves the feel, but if that is unsuccessful I'm considering fitting a larger m/c e.g. 17mm off a 600RR, to replace the current 15.87mm 600F4i part; I know that sounds contrary but that m/c works really well on my VTR.

I'd be interested to hear of other users of the 600F4i parts, and whether their experiences are similar to mine.

[AMCQ46]

Twitchy,
more interesting data, especially the axial to radial conversion. would be good if you could send a photo of the 2 levers side by side so I can see what the mechanical advantage variation is.

Cadbury,
i have good lever travel with the full F4i system fitted... defo not wooden feeling

[sirch345]

yes even though it was a long time ago, I still remember almost hitting the rear end of my brothers bike when my front solid disc brake on my Honda CB400four took time for the water to disperse before it worked
You just had to remember to calculate that into your stopping time
My excuse was, the bike was new to me and it was the first time I'd been out in the wet.

Chris.

You just reminded me of my first "big bike" Chris.

Honda CB550 77' vintage, it had been cafe racer'd & I couldn't afford new pads for the front caliper (with solid disc). So I removed the caliper completely 100mph never felt so darn fast

Can't believe the stuff I used to do on bikes, this was before I had a licence too

That sounds scary Jamie, you naughty boy

Apologies for thread highjack

Chris.

[Twitchy]

Twitchy,
more interesting data, especially the axial to radial conversion.

User 'chemomche' on SH forum, "Mods - Performance" board, "List of Bolt-On Front Brake Mods" thread;

"and about the MC sizes i got some researches, because i needed MC for my Supermoto

radial and axial MC sizes are e bit diffrent
for 4 pot calipers use 14mm axial or 17-18mm radial MC
for 6 pot calipers - 16mm axial(the original gsxr is 16mm) and 18-19mm radial"

...would be good if you could send a photo of the 2 levers side by side...

My stock levers still on the bike, but will try to get a comparison photo over the weekend.

[Cadbury64]

Twitchy,
more interesting data, especially the axial to radial conversion. would be good if you could send a photo of the 2 levers side by side so I can see what the mechanical advantage variation is.

Cadbury,
i have good lever travel with the full F4i system fitted... defo not wooden feeling

I fitted some EBC HH pads, cleaned the discs with scotchbrite pad and the brake cleaner. I also checked for disc runout, one was perfect, and I had 0.06mm on the other, which isn't perfect but is within the 0.3mm spec limit. At first the brakes were still very average, but after 50km I could see that the pads weren't contacting the whole disc face, as the VFR discs seem to have a narrower pad than the CBR, and my old 92000km discs had some high spots at the rim and next to the bobbins. Anyway, some more mileage has sorted them out, after another 200km the power and feel has come on in leaps and bounds as the pad mates to the disc. Happy again!

[Twitchy]

Can anyone confirm the REAR brake caliper from an SP2 is a direct bolt in to the VTR? I have checked Partzilla, and all the part numbers are the same, but the mounting bracket to the swingarm are different.

I figure if I put SP2 calipers (gold colour) on the front, then it would be sensible to put a gold caliper on the rear to match.

Thanks.

[lloydie]

Firestorm early calipers are gold .

[AMCQ46]

radial and axial MC sizes are e bit diffrent
for 4 pot calipers use 14mm axial or 17-18mm radial MC
for 6 pot calipers - 16mm axial(the original gsxr is 16mm) and 18-19mm radial"
.

interesting.... so when you get the photos side by side I am expecting to see the lever arm effect (the distance from the pivot bolt, to the MC actuating point) to be 65% smaller on the Radial lever, then it will all make sense from an engineering point of view

[AMCQ46]

so after some school boy maths on that picture the answer is ...... 62% more mechanical leverage, hence the master cyl area has to be 62% bigger [note this is area, not diameter.... area is the square of diameter].


so that is why a bigger MC is used on the radial.

[lloydie]

Are you not getting any again al ?
Good home work tho [THUMBS UP SIGN]

[AMCQ46]

Are you not getting any again al ? ]

sadly no

but then again I am at work, so it would be a bit much to hope to get laid and paid

[Twitchy]

Difficult to get a pic with the levers lines up, but here's a side by side shot;


Lever comparison - 2006 CBR1000RR on top, standard VTR1000 below;


CBR pivot to lever pull - 110mm;


VTR pivot to lever pull - 80mm;


CBR radial m/c centre of pivot to centre of piston shaft - 19mm;


VTR m/c centre of pivot to centre of piston shaft (done on bike so approximate) - 25mm

**Please note the measurements are of a 2006 Firestorm with integrated reservoir.

[Twitchy]

On a side topic, where have you guys sourced the extended brake lines? From the manufacturer direct (Speigler, HEL etc)? Or some other aftermarket joint?