[bigbird]

In several discussions on this and on other boards many Bobber owners posted their unhappiness about the weak performance of the Bobber´s front brake. So it's time to bring some light into darkness:

The wooden feel at the brake lever and the weak deceleration combined with very high lever force are clearly caused by the bad hydraulic transmission ratio between the master cylinder piston (diameter 14 mm) and the original Nissin 2pot caliper pistons (diameter 27 mm each). This gives us a ratio of 1145/154 = 7.4, while the ideal ratio for a single disc motorcycle front brake layout would be 13.5 in order to get a sensitiv 2 finger brake! This is, what we want, not for our comfort, but for safety reasons! Ok, some comfort doesn't hurt!:grin2:

At this Point I must mention, that Triumph uses the same 14 mm master cylinder for their dual disc layouts, which doubles the hydraulic ratio due to the doubled caliper piston area!

Plan A:
Why not swap the master cylinder to a Motocross bike 11mm master cylinder for a few bucks (ebay)? This would bring the hydraulic ratio up to 12 clean and easy! Bad idea! Our Hightech-Bobber is equipped with "Throttle by wire"! Last but not least, the ABS system could be harmed somehow by the higher pressure in the system. And just to be honest: I don't like the imagination to ride the heavy Bobber with a Crossbike brake!

Plan B:
Let's put a bigger caliper onto the fork. Bad idea! Unfortunately there isn't enough space for a bigger caliper between the brake disc and the flat angled spokes of the big 19" wheel! No matter, let us grab one of this Honda CB 1000 or VFR 800 Nissin 3pots on ebay, link the originally rear brake acted center piston to the others, and there we go! Not at all: The Nissin 3pot has two 22mm pistons and one 25mm piston, giving us a hydraulic ratio of just 8.1! This isn't worth the money. And again to be honest: The modified 3pot with its two bleeding valves and two brake hose fittings isn't a beauty!

So what else could we try? Now, some guys were not afraid to spend the money, and installed Behringer or Pretech 6pot calipers on their bikes, after they had swapped the disc to a fat 340mm floating disc. They had a little improvement, yes indeed, because the total piston area of the 6pots was slightly larger. But again, it was by far not worth the money!

But 2018 things are changing! God had an insight and let Brembo design a brandnew, ultra slim 4pot caliper for Supermoto bikes, expensive, but with really fat 34mm pistons! And God let some Bobber specialists in Italy make a front brake upgrade kit for the Bobber with this caliper and a 340mm fully floating disc! Plug and Play!

Look at that:

https://www.freespiritsparts.com/en...onneville-t100-front-brake-caliper-4-pot.html

This setup brings the hydraulic ratio up to 11.8! Just by this the lever force would drop to 62%, but the caliper clamps 4 seperate double sintered brake pads onto a 340mm disc! So there is no doubt, that this setup will boost the braking performance of my Bobber to the desired level regarding safety, sensitivity, power and comfort!

You guys must be strong now, but sad to say the first kit built is sold already! Guess to whom!:grin2:

Stay tuned!

 

[Mike the Bike]

Welcome to the forum!

885.00€ euros + tax+shipping? Wow!

I'll be going for the 6 pot Pretech one I think.

Thanks for posting

mike

 

[eisen77]

In several discussions on this and on other boards many Bobber owners posted their unhappiness about the weak performance of the Bobber´s front brake. So it's time to bring some light into darkness:

The wooden feel at the brake lever and the weak deceleration combined with very high lever force are clearly caused by the bad hydraulic transmission ratio between the master cylinder piston (diameter 14 mm) and the original Nissin 2pot caliper pistons (diameter 27 mm each). This gives us a ratio of 1145/154 = 7.4, while the ideal ratio for a single disc motorcycle front brake layout would be 13.5 in order to get a sensitiv 2 finger brake! This is, what we want, not for our comfort, but for safety reasons! Ok, some comfort doesn't hurt!:grin2:

At this Point I must mention, that Triumph uses the same 14 mm master cylinder for their dual disc layouts, which doubles the hydraulic ratio due to the doubled caliper piston area!

Plan A:
Why not swap the master cylinder to a Motocross bike 11mm master cylinder for a few bucks (ebay)? This would bring the hydraulic ratio up to 12 clean and easy! Bad idea! Our Hightech-Bobber is equipped with "Throttle by wire"! Last but not least, the ABS system could be harmed somehow by the higher pressure in the system. And just to be honest: I don't like the imagination to ride the heavy Bobber with a Crossbike brake!

Plan B:
Let's put a bigger caliper onto the fork. Bad idea! Unfortunately there isn't enough space for a bigger caliper between the brake disc and the flat angled spokes of the big 19" wheel! No matter, let us grab one of this Honda CB 1000 or VFR 800 Nissin 3pots on ebay, link the originally rear brake acted center piston to the others, and there we go! Not at all: The Nissin 3pot has two 22mm pistons and one 25mm piston, giving us a hydraulic ratio of just 8.1! This isn't worth the money. And again to be honest: The modified 3pot with its two bleeding valves and two brake hose fittings isn't a beauty!

So what else could we try? Now, some guys were not afraid to spend the money, and installed Behringer or Pretech 6pot calipers on their bikes, after they had swapped the disc to a fat 340mm floating disc. They had a little improvement, yes indeed, because the total piston area of the 6pots was slightly larger. But again, it was by far not worth the money!

But 2018 things are changing! God had an insight and let Brembo design a brandnew, ultra slim 4pot caliper for Supermoto bikes, expensive, but with really fat 34mm pistons! And God let some Bobber specialists in Italy make a front brake upgrade kit for the Bobber with this caliper and a 340mm fully floating disc! Plug and Play!

Look at that:

https://www.freespiritsparts.com/en...onneville-t100-front-brake-caliper-4-pot.html

This setup brings the hydraulic ratio up to 11.8! Just by this the lever force would drop to 62%, but the caliper clamps 4 seperate double sintered brake pads onto a 340mm disc! So there is no doubt, that this setup will boost the braking performance of my Bobber to the desired level regarding safety, sensitivity, power and comfort!

You guys must be strong now, but sad to say the first kit built is sold already! Guess to whom!:grin2:

Stay tuned!

A great first post!
Welcome to the forum :smile2:

I´m with Mike on this one - and going to try a 6 pot first. But i look forward to hearing your review and i´m sure it is money well spent.

 

[MikeB]

Thanks for the post. I too look forward to hearing your review.

As A&J Cycles is a dealer, it'll be interesting to see their price for this kit.

 

[trirocket3]

The Pretech 6 pot will fit with stock disc, & they have one in the pipeline for a 340 disc, which I have test fitted ( dry) to my bike.
They should have some available sometime in Feb.
QUOTE 'Not worth the money' UNQUOTE
The Pretechs would be easily a couple of HUNDRED POUNDS less than those 4 pots.
Personally I hate adapter brackets to make a caliper fit, the Pretech is made for this bike it just bolts on, no bracket required.
But it is always nice to have different options.

 

[bigbird]

Life is what you make it, folks!

I assume that the sexy 6pot Pretech caliper will not fit the original 310mm disc on the Bobber's 19" wheel.:crying:
If it does, the pistons will need to be very, very small! But the 6pot caliper must have 28 mm pistons to beat my Brembo beast's total piston area! This is a though challenge, not an easy going! A propper piston area is our goal, believe me folks! Other mods are more or less just cosmetic!

And folks: Don't forget to buy a floating disc as well!

Stay tuned!:grin2:

 

[Mike the Bike]

I also prefer things that are made specifically for the bike; especially here, where safety is the main concern. Adapters seem like a compromise to me; sort of a "one size fits all" thing. Here in Germany, the TÜV Type Approval (MOT) system probably won't allow an adapter on a brake caliper anyway.

So I'm going with the 6 pot Pretech later this year. It does fit the original disc by the way, as "Trirocket3" mentioned.

However, it'll be interesting to hear how you all get along with these different systems. Looking forward to that.
After almost a year of the bobber, the market for after-sales parts, accessories and upgrades is really taking off now, with all sorts of companies jumping on the band-wagon... good for us!

Cheers!
mike

 

[bigbird]

Get your feet back on the ground, folks! Do you really think it's usual to design and produce a unique caliper for every different bike all around the globe? You must be joking!

Even the biggest players on the market (Triumph as well) don't develop braking components by themselves, but derive these parts from specialized manufacturers like Brembo or Nissin. Usually they use 2 or 3 different standart calipers, mostly floating calipers, for their whole range of bikes using either the same fork or different brackets!

As I mentionned above, my goal is a sensibly responding, precisely controllable and stable two finger brake in order to get the maximum braking performance! If it eventually looks nice too, I don't worry about, but form must follow function!

I owned several types of bikes in my life, Enduros, Touring bikes, Supersport bikes. So I am not the typical chopper rider. I baught the Bobber, because it is a very ridable bike despite of its classic custom appearance. So the point is: I am going for the perfect brake, which eventually looks pretty good too, but not for the perfect look, which eventually brakes pretty good too!

Life is what you make it, folks!:grin2:

@ mike the bike:
1.) As mentionned above, safety is my main concern indeed: Maximum braking performance = maximum passive safety! 2.) I cannot see any difference in the technical evaluation between a special Pretech caliper and a standart Brembo caliper with a special bracket!

 

[Mike the Bike]

We're not joking at all mate.:smile2:
It's trivial and quite normal for a large manufacturer like Brembo or Nissin to make several series of brake calipers to suit different categories of motorcycles; and have their Foundry cast quite a lot of different castings, to then be machined and fitted to certain bikes within the said categories.

You're indeed quite right saying there's no real difference in the mechanical stability whether with, or without an adapter. However, in my case though, it's just my personal preference and what I feel comfortable with. And also I certainly have to consider what the German TÜV (MOT) will be happy with, or they won't give their blessing! They don't allow any kind of adapters on such safety related items as brakes etc.

I also definitely agree on form follows function, absolutely.:wink2: And the Brembo certainly looks nice too!

Cheers! Have nice weekend
mike

 

[bigbird]

Did somebody recognize, that the Brembo-Beast has 4 seperate brakepads (1 for each piston), that can be changed with on the fly without any tool from above? This will make me faster on the race track! :wink2:

Have a nice weekend and keep dreaming of a well performing Bobber front brake! Warmest condolences to Germany, where in fact the TÜV is braking the bikes! :grin2:

 

[PFEN]

with the new speed limit at 80km/h in France.:crying: the original brake is enough for me.0
and at this rate, good tread under my shoes should be enough >

 

[bigbird]

:grin2::grin2::grin2:
Our new Minister for Traffic is willing to lift the speed limits and willing to forbid the police to control speed on nonhazardous stretches of road! So come here! They let us use throttle and brakes in Austria!:grin2:

Obviously they are dividing us Bobber riders into two divisions: Those, who need fat brakes, and those who don't need brakes at all.

But don't worry, PEN, on the other hand you can live the spirit of "bobbing your bike" easier: strip everything, you don't really need, such as fenders, lights, rear shock, front brake, etc.!:grin2:

 

[bigbird]

@ MikeB:wink2::

My name is Werner. Werner Wernersen!>

 

[Calthi]

Hi,

I’ve installed a Brembo brake with the same caracteristics as bigbird discribed (340mm floating disc, 4 pistons caliper) but which was designed for the street twin & street cup.
The dealer had to slidly slice the rear of the caliper by 1mm to avoid the interference with the spokes. That’s surely why Brembo made a new caliper in the meanwhile.
The result is exactly what bigbird discribed in terms of feeling and efficiency of the front brake.

 

[bigbird]

Happy to hear that theory prooves true in reality!

Your caliper is a Brembo P4 30/34mm with 2 pads. It is designed completely different to the new P4 34/34 Supermoto, which has 4 pads and costs about the half. Brembo didn't just cut off a slice of aluminium and double the price!

But anyway: Yours improves the hydraulic ratio from 7.4 to 10.5! So I'm not wondering about a very noticable, much better performance and a way more sensitiv control! Thumbs up!!!

Werner Wernersen>

 

[BOBBYP]

In several discussions on this and on other boards many Bobber owners posted their unhappiness about the weak performance of the Bobber´s front brake. So it's time to bring some light into darkness:

The wooden feel at the brake lever and the weak deceleration combined with very high lever force are clearly caused by the bad hydraulic transmission ratio between the master cylinder piston (diameter 14 mm) and the original Nissin 2pot caliper pistons (diameter 27 mm each). This gives us a ratio of 1145/154 = 7.4, while the ideal ratio for a single disc motorcycle front brake layout would be 13.5 in order to get a sensitiv 2 finger brake! This is, what we want, not for our comfort, but for safety reasons! Ok, some comfort doesn't hurt!:grin2:

At this Point I must mention, that Triumph uses the same 14 mm master cylinder for their dual disc layouts, which doubles the hydraulic ratio due to the doubled caliper piston area!

Plan A:
Why not swap the master cylinder to a Motocross bike 11mm master cylinder for a few bucks (ebay)? This would bring the hydraulic ratio up to 12 clean and easy! Bad idea! Our Hightech-Bobber is equipped with "Throttle by wire"! Last but not least, the ABS system could be harmed somehow by the higher pressure in the system. And just to be honest: I don't like the imagination to ride the heavy Bobber with a Crossbike brake!

Plan B:
Let's put a bigger caliper onto the fork. Bad idea! Unfortunately there isn't enough space for a bigger caliper between the brake disc and the flat angled spokes of the big 19" wheel! No matter, let us grab one of this Honda CB 1000 or VFR 800 Nissin 3pots on ebay, link the originally rear brake acted center piston to the others, and there we go! Not at all: The Nissin 3pot has two 22mm pistons and one 25mm piston, giving us a hydraulic ratio of just 8.1! This isn't worth the money. And again to be honest: The modified 3pot with its two bleeding valves and two brake hose fittings isn't a beauty!

So what else could we try? Now, some guys were not afraid to spend the money, and installed Behringer or Pretech 6pot calipers on their bikes, after they had swapped the disc to a fat 340mm floating disc. They had a little improvement, yes indeed, because the total piston area of the 6pots was slightly larger. But again, it was by far not worth the money!

But 2018 things are changing! God had an insight and let Brembo design a brandnew, ultra slim 4pot caliper for Supermoto bikes, expensive, but with really fat 34mm pistons! And God let some Bobber specialists in Italy make a front brake upgrade kit for the Bobber with this caliper and a 340mm fully floating disc! Plug and Play!

Look at that:

https://www.freespiritsparts.com/en...onneville-t100-front-brake-caliper-4-pot.html

This setup brings the hydraulic ratio up to 11.8! Just by this the lever force would drop to 62%, but the caliper clamps 4 seperate double sintered brake pads onto a 340mm disc! So there is no doubt, that this setup will boost the braking performance of my Bobber to the desired level regarding safety, sensitivity, power and comfort!

You guys must be strong now, but sad to say the first kit built is sold already! Guess to whom!:grin2:

Stay tuned!

PLAN A: Ride a Harley for a few hours, then jump on a Bobber!

PLAN B: Go to the Gym!!!


PLAN C: All of the above!



But seriously my stock Bobber will Bang off the ABS at 40 or 50 MPH on a dry road, I don't see where I need more power.

After riding one of my Harleys the Bobber brakes feel great! After riding the Norton with Twin 330MM Brembo Monoblocks the Bobber certainly doesn't have the 1 finger feel but still plenty of power with 2 or 3 fingers!!!>

 

[bigbird]

Ouch, that hit home!:crying:

But hey man, you must know: I live in a very mountainous country. So I cannot imagine in fact, what a straight road looks like! Furthermore I'm way to young and weighing far to little, to ride around on one of this Harley hogs! THIS is why I baught this very ridable Triumph Bobber!!!

I pimped it's suspension and threw the inclination indicators out befor the first ride! But soon I had to recognize: Even with the highest possible spring load (and my admittedly perfect weight shifting technique of course) I cannot corner as fast as with my Honda Fireblade, because of this fucking exhaust pipes! So there is no joice: I have to make it on the brakes!!!

Werner Wernersen >

 

[MikeB]

@ MikeB:wink2::

My name is Werner. Werner Wernersen!>

Got it Werner!

 

[MikeB]

But 2018 things are changing! God had an insight and let Brembo design a brandnew, ultra slim 4pot caliper for Supermoto bikes, expensive, but with really fat 34mm pistons! And God let some Bobber specialists in Italy make a front brake upgrade kit for the Bobber with this caliper and a 340mm fully floating disc! Plug and Play!

For my clarity, does this Free Spirits Brembo brake kit come with the 340mm fully floating disc?

 

[bigbird]

Yes, the kit does include the 340mm disc, and all the other hardware needed for installation. Should get mine by the end of the week.