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Cost effective brake update for the NC

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Hati

I'm in the fourth year of the ownership of the (same) Integra and still loving it. By now I either changed all the bits I didn't like or made peace with them (mostly the former).

 

The one thing that was on my list and done nothing about was the brakes. I don't have a problem with the factory brakes in general, but if I need to emergency brake for any reason, I need to use four fingers. Two is enough usually for most instances, but true emergencies need double that. I didn't want to change calipers and discs, that is just silly money, but one option that I have not heard anyone here mention is replacing the brake lines with something better.

 

I came across the Italian Fren Tubo company that makes brake line kits for many bikes, including the Integra. They have 4 grades: steel braided with steel fittings, steel braided with ally fittings, kevlar with ally and carbon fibre with ally. Colours can be chosen within reason. I went for the kevlar set for 128 euros. Ordered other bits from the shop it came from (Carpimoto), so postage was cheap even to here.

 

I ordered and received the kit a few months ago, just waited for the 48k service to be due to install it. With the Integra you need to remove every piece of bodywork except the tail to replace brake lines, so I wanted to tackle that only once when I do the valves (also most of the bodywork needs to be removed). Yesterday was the day. After all the service items were completed, I fitted the four lines. The fit and finish is pretty good, especially the finish. The rear line could have been better angled, I had to use a cable tie to keep it out of the way of a frame reinforcement that could have rubbed the line when the swing arm was moving up and down. The front 3 (2 for front brake and one for the rear) fitted better.

 

When I started to bleed the lines, I thought I had a leak at first, the feel at the brake lever was so different. It was softer funnily enough. I expected the kevlar lines (that do not stretch under pressure like rubber lines do) to make the brakes feel harder. It was the opposite. I went through 4 reservoirs of brake fluid until I was convinced that it is how it meant to feel and there was no air left in the line.

 

Today I went out for a ride. OMG !!!!! What a difference!!! Like a different machine. Two finger emergency braking no longer a problem. There is a vastly improved feel at any stage of using the brakes. Much easier to modulate braking too. Probably the most significant upgrade the NC can have, in line with suspension and seat replacements.

 

Conclusion: money well spent, highly recommended upgrade. If you do this yourself, allow a comfortable half to full day to do this on an Integra. Don't know what the X and S are like covering up the bits you need to get to.

 

 

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Mr Toad

Swapping to braided brake line hoses used to be a common upgrade when brakes weren't as good at stopping as the bike was at accelerating. It's not something I've thoight about for years. On my Bonneville, Hinkley variety, I improved the front brake by simply replacing the pads with better ones.

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SteveThackery

I don't understand how this can possibly work.

 

The clamping force of the pads on the discs is determined SOLELY by the lever ratio and the hydraulic ratio multiplied together.  The stretchiness of the brake lines is not a factor.

 

To be specific: stretchy brake lines mean you must pull the lever further in order to generate a particular braking force (the stretchier the lines, the "spongier" the lever so the further you must pull it).  But in terms of actual braking force - rigid lines simply cannot increase it; to do so would violate the laws of physics.

 

I think any improvement is in the FEEL of the brakes, not the actual stopping power.

 

Can anyone demonstrate that I'm wrong? 

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Mr Toad
29 minutes ago, SteveThackery said:

I don't understand how this can possibly work.

 

The clamping force of the pads on the discs is determined SOLELY by the lever ratio and the hydraulic ratio multiplied together.  The stretchiness of the brake lines is not a factor.

 

To be specific: stretchy brake lines mean you must pull the lever further in order to generate a particular braking force (the stretchier the lines, the "spongier" the lever so the further you must pull it).  But in terms of actual braking force - rigid lines simply cannot increase it; to do so would violate the laws of physics.

 

I think any improvement is in the FEEL of the brakes, not the actual stopping power.

 

Can anyone demonstrate that I'm wrong? 

 

Perhaps due to the rubber hose bulging under pressure it means that before you reach the point of maximum braking the lever hits the bars. No swelling due to upgraded hoses means that you get better braking before the lever hits the bars. 

 

I have no evidence that this is the case though.

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slowboy
7 hours ago, SteveThackery said:

I don't understand how this can possibly work.

 

The clamping force of the pads on the discs is determined SOLELY by the lever ratio and the hydraulic ratio multiplied together.  The stretchiness of the brake lines is not a factor.

 

To be specific: stretchy brake lines mean you must pull the lever further in order to generate a particular braking force (the stretchier the lines, the "spongier" the lever so the further you must pull it).  But in terms of actual braking force - rigid lines simply cannot increase it; to do so would violate the laws of physics.

 

I think any improvement is in the FEEL of the brakes, not the actual stopping power.

 

Can anyone demonstrate that I'm wrong? 

Spot on Steve, (but then you knew that) it can only improve the feel due to a reduction in lost motion. The power of the brakes is determined by the grip between the tyre and the road (when the tyre runs out of grip, it either locks or the ABS kicks in) I know the pads can effect the feel too (initial bite), maybe Andy can give us an expert view of that. The ability to shed the heat generated efficiently also has an effect.

Mr Toad, if the lever comes back to the bars without giving max braking, that's a serious fault, suggesting a flexible has partially failed, a piston has seized or a seal has partially failed. Scary stuff.

Edited by slowboy

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rainmaker

Stretching the rubber uses energy (completely wasted), which otherwise would be applied to the pads/disks. That's how I am thinking. I was planing of braided hoses upgrade on my NC as brakes were one thing I disliked. 

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SteveThackery
9 minutes ago, rainmaker said:

Stretching the rubber uses energy (completely wasted), which otherwise would be applied to the pads/disks. That's how I am thinking. I was planing of braided hoses upgrade on my NC as brakes were one thing I disliked. 

 

But it's not energy you want applied to the pads, it's force.

 

And the force applied to the discs is:  force applied to lever * lever ratio * hydraulic ratio

 

With spongy lines you must pull the lever further inwards to generate a particular force, that's all.

 

I would imagine there is probably an optimum distance between the lever and the bar, at which your hand will be able to apply the maximum force.  Presumably it's greater for those with large hands, and vice versa, hence why many levers are adjustable.  I guess that if the lever travels in much further than the optimum point (due to spongy lines), it's harder for you to apply the required force to the lever.  That's the only explanation I can think of for saying the brakes are better with "stiffer" lines.  It would be more accurate to say your hand is operating more effectively.  Assuming there's anything in this theory.  :)

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Rev Ken
17 minutes ago, rainmaker said:

Stretching the rubber uses energy (completely wasted), which otherwise would be applied to the pads/disks. That's how I am thinking. I was planing of braided hoses upgrade on my NC as brakes were one thing I disliked. 

Sorry - even of they stretch like balloons, the same pressure exerted on the brake lever (so long as it doesn't hit the twist grip) gives the same braking force on the disc, ie the front tyre on the road. The difference is that you don't have to pull the brake lever as far to get the same braking force and it will feel more 'direct', giving more confidence in its efficiency.

 

Ooops, I was delayed in posting my response - I'm glad we agree!

 

Second edit: If you are using two fingers to brake, then it isn't possible to pull the brake lever as far as the rest of your fingers get in the way, especially when doing and emergency stop.

Edited by Rev Ken

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pauloski

As my other bikes are sports bikes, the NC brakes are my biggest concern. they feel terrible and i cant one or two finger brake into turns like i do with my other bikes. on track mainly you drag the front till the apex sometimes with one finger (at least on my R1) and on the NC i need to remember to use all my fingers when i want to stop quickly.  i am still getting used to a number of aspects of this bike, but this is the biggest one. i am slightly worried that i am training my brain to ride differently,  but as i am about to convert my track bike to race shift, it's the least of my worries :)

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Hati
1 hour ago, Rev Ken said:

 If you are using two fingers to brake, then it isn't possible to pull the brake lever as far as the rest of your fingers get in the way, especially when doing and emergency stop.

 

Emergency stop braking does not equal brake levers against the grips. There is room for fingers between. The problem is that I havn't got enough strength in two fingers to achieve the pressure required for emergency braking with the standard brake lines.

 

9 hours ago, SteveThackery said:

I don't understand how this can possibly work

 

The rubber hose will balloon to some degree when brakes are applies. If you had steel/solid brake lines right through, then your reasoning would stand. If rubber is introduced, some of the pressure that is applied to the lever will be spent ballooning the hose instead. Remove the ballooning and you have a very noticeable transformation. That is of course assuming the lever was pulled over the same distance. Pretty sure I mentioned that (same distance) by talking about using two fingers that now can do emergency braking too.

 

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Tex
1 hour ago, pauloski said:

 but as i am about to convert my track bike to race shift, it's the least of my worries :)

 

Be very careful. Most of the racers I know who ride regularly on the road have road shift on their race bikes to avoid the ‘muscle memory’ disasters. One who didn’t (his race bike was right foot shift and he felt it was ‘different’ enough to keep him focused) broke a collar bone and both wrists when, in the heat of battle, he selected 2nd when WFO in 3rd.. 

 

 

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SteveThackery
1 hour ago, Hati said:

If you had steel/solid brake lines right through, then your reasoning would stand. If rubber is introduced, some of the pressure that is applied to the lever will be spent ballooning the hose instead. Remove the ballooning and you have a very noticeable transformation. That is of course assuming the lever was pulled over the same distance. Pretty sure I mentioned that (same distance) by talking about using two fingers that now can do emergency braking too.

 

 

Sorry, but it just doesn't work like that.  You don't "spend" pressure ballooning the hose.  Think it through in your mind's eye - you "spend" lever movement, not lever pressure.  You give yourself away when you say "the lever was pulled the same distance".  It goes without saying that spongy brake lines will require you to pull the lever further in order to apply a given force - that much is obvious and not in dispute. 

 

But you implied that you can apply less lever pressure for a given braking force (i.e. only two fingers instead of four).  As I've said before, there is nothing in the laws of physics that allows you to apply less lever pressure for a given braking force just by making the hoses stiffer.  All you will get is less sponginess and therefore less lever travel.

 

I think the reduced travel (less sponginess) is fooling you into thinking you don't need as much force on the lever.  Also, I think the closer the lever gets to the handlebar (as happens with ballooning brake lines) the more difficult it is to apply the required  braking force.

 

I repeat my conclusion: it's your hand that's working better, not the brakes.

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KeithReeder
21 minutes ago, SteveThackery said:

 

Sorry, but it just doesn't work like that.  You don't "spend" pressure ballooning the hose. 

 

This.

 

The only way that movement at the lever would be completely wasted is if there was a leak in the system: otherwise - it being a closed system - the ballooning is incidental (more or less) to the pressure at the caliper.

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old commuter

Very complicated but it seems to have worked and you are happy with your change so great. I am lazy in this respect and just stick with the set up. I the week before I plan a ride I plan when I will brake and do that visualising stuff luge runners etc do. Then I go out with my plan😀

 

those luge riders are brave

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Hati

 

6 hours ago, SteveThackery said:

I repeat my conclusion: it's your hand that's working better, not the brakes.

 

The what?? My hand working better? I replaced nothing in my hand neither have I been pumping iron to get stronger.

 

Since you are so good at picking on wording, have a look at the subject explained by a mechanical engineer here:

 

 

What he explains is what I was talking about, but hey, knock yourself out Einstein, err Steve.

 

Edited by Hati

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Andy m

Sales pitch from the supplier. They are right, steel coil springs added round the outside balloon ever so slightly less than rubber with just the internal structures. The rubber still compresses into the weave , but we are only talking a few hundred PSI not the sort of pressure you get with lifting hydraulics (which also use normal hose). The standard hose is already a layered structure, its not like the gas hose on a school lab bunsen . Its mostly window dressing, the effect on your mind and the fact the guys doing retrofit do a better job of bleeding. The downside they also note, its harder to inspect, but not usually a problem on weekend use bikes.

 

I've been a brake engineer for 25 years. I was a test engineer doing type approvals for 7 years. I met a few hydraulic systems that wouldn't perform, none were fixed with shiny hose and the only one fixed with bathroom plumbing was one the Army kept ripping the bottom out of.

 

So long as you are happy, whatever worked worked. Feel is important on a lot of vehicles as drivers/ riders run out of confidence long before they run out of available decel.

 

Andy

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MikeBike
1 hour ago, Hati said:

 

 

The what?? My hand working better? I replaced nothing in my hand neither have I been pumping iron to get stronger.

 

Since you are so good at picking on wording, have a look at the subject explained by a mechanical engineer here:

 

 

What he explains is what I was talking about, but hey, knock yourself out Einstein, err Steve.

 

Haiti, there's.no need to be rude and make it personal. We all make mistakes and others here are trying to help you and other readers understand. One of the things people enjoy here is the civilised responses.

The guy in the video (you say he's a mechanical engineer) says that there's less less pressure on the brake caliper piston because of the ballooning of the pipe. As others have said (and I'll add my £0.02) as a chartered engineer the force applied on the brake lever results in a pressure in the fluid. That pressure isn't selective where it applies itself so acts on the brakes just as it acts on the hose.

What is different is that to get to a certain pressure you will have to squeeze more. Ah you might say yes, squeeze more! But squeeze more distance on the lever, not more force than rigid lines. Pressure is force divided by area (of the cylinder piston) Nothing in there about volume,  stretch etc. Same in reverse at the brake end. Force is pressure times area (of brake caliper piston face)

 

You may want to just reconsider this and what others have said and thank them for their help in understanding, rather than getting frustrated.

 

 

 

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Hati

Ah, my apologies, I shall crawl back in my hole now and have a severe talking to myself about imagining things, such as improvements in brake feel (I imagined I experienced) when the brake lines were changed.

 

It must be my hand and the improvements I thought I felt was completely placebo. Sorry to have bothered you all. it won't happen again...

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MikeBike

Don't think anyone said it wouldn't feel better, the reverse I think. Feel more responsive as shorter travel of the lever for the same force.

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DaveM59

Hati is totally correct. You doubters are all missing one important thing. When the free play is taken up at the pad to disk, the pad becomes an immovable object so as pressure is applied to the back of it, any softness in the brake lines absorbs that pressure rather than it all being applied as braking force. The limited travel and small fluid capacity of a bike master cylinder means this loss is exaggerated and seen as more lever travel. It's only the fact that the rubber pipes don't have unlimited ballooning but still have a limit that allows any pressure to be placed on the pads. Lower this limit and more of the applied pressure is aplied to the pads. After all the pressure is a ratio of fluid volume moved at the master cylinder to that at the calliper and any loss of volume at the calliper is a reduction in ratio. Fluid displacement ratio is what counts and any losses are seen as increased input requirement for the desired output.

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Bigglesaircraft
49 minutes ago, MikeBike said:

Haiti, there's.no need to be rude and make it personal. We all make mistakes and others here are trying to help you and other readers understand. One of the things people enjoy here is the civilised responses.

The guy in the video (you say he's a mechanical engineer) says that there's less less pressure on the brake caliper piston because of the ballooning of the pipe. As others have said (and I'll add my £0.02) as a chartered engineer the force applied on the brake lever results in a pressure in the fluid. That pressure isn't selective where it applies itself so acts on the brakes just as it acts on the hose.

What is different is that to get to a certain pressure you will have to squeeze more. Ah you might say yes, squeeze more! But squeeze more distance on the lever, not more force than rigid lines. Pressure is force divided by area (of the cylinder piston) Nothing in there about volume,  stretch etc. Same in reverse at the brake end. Force is pressure times area (of brake caliper piston face)

 

You may want to just reconsider this and what others have said and thank them for their help in understanding, rather than getting frustrated.

 

 

 

 

Perhaps this gives another view on the subject.

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MikeBike
30 minutes ago, Bigglesaircraft said:

 

Perhaps this gives another view on the subject.

Quote: at 00:00:20 "it doesn't make your brakes WORK any better"

and then 20 seconds later says "you can brake later in the corners"

Doh.

then most of video fitting then concludes not much difference.

Edited by MikeBike
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KeithReeder
1 hour ago, DaveM59 said:

The limited travel and small fluid capacity of a bike master cylinder means this loss is exaggerated and seen as more lever travel

 

But it's not "loss", Dave - that's the point. It doesn't matter - in terms of the pressure available to actuate the pistons - whether the brake line has expanded (slightly - we're not talking about bulges) under pressure.

 

You might - conceivably - get a better feel at the lever if the brake line that was replaced was really shot; but given that it probably won't be (as Andy points out, brake lines are tough, designed-for-the-job components, not bunsen burner tubes), any gains at the lever will be marginal; and at the piston, pretty much non-existent. Again., it's a closed system, so there's nowhere for the pressure to go, and the lines are not swelling up like inner tubes. 

 

Edited by KeithReeder
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Bigglesaircraft
9 minutes ago, KeithReeder said:

 

But it's not "loss", Dave - that's the point. It doesn't matter - in terms of the pressure available to actuate the pistons - whether the brake line has expanded (slightly - we're not talking about bulges) under pressure.

 

You might - conceivably - get a better feel at the lever if the brake line that was replaced was really shot; but given that it probably won't be (as Andy points out, brake lines are tough, designed-for-the-job components, not bunsen burner tubes), any gains at the lever will be marginal; and at the piston, pretty much non-existent. Again., it's a closed system, so there's nowhere for the pressure to go, and the lines are not swelling up like inner tubes. 

 

Totally agree with you, I only posted the video as another point of view. The only time I have ever found it necessary to use any reinforcement on brake lines is when I was was building Rally cars for the forest and then all lines were run inside the car where possible and anything external was either protected or reinforced flexible hoses.

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KeithReeder

It was Dave59 I was replying to, David (just in case you thought otherwise) - I completely understand the point of you posting up the vid.

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