Apparently the newer 2012 Shimano brakes use a narrower bore hose (taking a silver, rather than gold, insert) which increases performance a little. When the time comes to bleed my old M585 lever/M595 caliper setup would changing from the old style hose to the narrower bore one make a difference or just be pointless faff?

Anyone?

How would a narrower hose alter the performance? it won’t unless its also more rigid / less likely to swell. Marketing bollox

Well narrower bore could be argued to swell/expand/give stretch less. A smaller dia of the same material under the same stress will expand with the same strain. Strain is a percentage, so lets say 10% a bore of say 3mm will expand to 3.3mm and a bore of 4mm will expand to 4.4mm – the difference in volume and hence pressure could be considerable.

so TJ, you think you know more about making brakes than Shimano. You are a true genius.

Scruff, I would prefer it if you do not deride others for their lack of knowledge, life is a learning experience, I say we should lead by example.

pedant edit – I meant to say 3mm/4mm circumference.

Everything is marketing bollox to TJ, he probably still has a black & white TV

Toys19, But I know for a fact that TJ is full of it.

On a side note, the new brakes are 63% more betterer than the old ones.

Toys – even if the volume increases – which I doubt would be anything like your example. -the pressure will be the same just the lever travel will be greater. for a set amount of pressure at the lever you will get the same amount of pressure at the calliper – it all equalises whether its a balloon or a rigid steel tube

Scruff – how do you think a narrower hose will alter the performance of the brake?

Teej, that’s called moving the goal posts, you said

it won’t unless its also more rigid / less likely to swell.

and I showed you that actually it will swell less. So are you now saying that it doesn’t make any difference if the hose swells? What about if it expands more than the lever travel?

It swells less so that for the same lever travel you will get more piston travel. This will alter the feel and performance of the brake in a like for like for like comparison. Whether it alters it for the better or worse is purely subjective, but it is a fact that the hose will swell less. It appears that users like this, hence braided hoses etc.

It could alter the feel – it cannot alter eh overall power as that is a function of the ratios of master and slave cylinders and of the pad material / rotor size none of which you are changing

Ah unfortunately, it can. Strain energy is the work done by a load in displacment. In a linear system (assuming the hose material displaces linearly) its given by (load x displacement)/2. Less strain is less energy wasted stretching the hose longitudinally and in the hoop.