Hydraulic brake types?

[Jfpklondon]

what are the differences and pros and cons to the various types of hydraulic brakes?

 

[lpretro1]

Some use DOT fluid (Avid, Hayes, Hope) some use mineral fluid (Shimano). DOT fluid is horrible stuff which will strip your paint work if you don't get it off quick and not nice on skin. Mineral is more benign. DOT needs replacing every 2-3 years, mineral less so. Mineral retains a high boiling point longer than DOT. Shimano brakes are pretty bullet proof - just as well as it is nigh impossible to get repair kits for them. Others like Avid can suffer from sticking pistons if not used a lot.

 

[Citius]

what are the differences and pros and cons to the various types of hydraulic brakes?

Can you be a bit more specific?

 

[Jfpklondon]

Hydraulic or mechanical?

 

[Citius]

Hydraulic or mechanical?

Sorry, I still don't know what you mean.

 

[vickster]

what are the differences and pros and cons to the various types of hydraulic brakes?

Which ones are you looking at, brand and model, then someone may be able to help. It seems like TRP are good, Tektro less good, Shimano somewhere in the middle

Are you just looking at brakes or a whole bike with said brakes?

 

[flake99please]

I think the OP means the difference between full hydraulic, mechanically activated (wired) hydraulic disc brakes.

 

[Venod]

There are open & closed systems, most are open but I did have some Giant brakes that were a closed system.

Closed systems do not have an automatic expansion reservoir that the fluid can move into, and out of the main system, when it heats up and expands. An open system has such a reservoir. Almost all hydraulic disc bike brakes are open systems with the expansion reservoir as part of the brake lever (master cylinder) unit. . The problem with closed systems is that long downhill braking causes the fluid to expand, which causes the brakes to start dragging on their own, causing more heat and more drag, until the brakes lock up entirely.

 

[summerdays]

What happens if you don't replace the DOT fluid every 2-3years? Mine seem to be working fine, and unlike my husbands Shimano ones the don't seem to need bleeding every now and again. His experiences has put me off Shimano ones.

 

[lpretro1]

DOT fluid degrades with time - it changes from a nice light gold colour to more of a dark gold or even getting towards brown or if left too long grey sludge. As it degrades as it is very hygroscopic - ie it loves to absorb water - so it's performance deteriorates so it's boiling point reduces for example. So it needs to be replaced typically every 2-3 yrs.

 

[lpretro1]

There are open & closed systems, most are open but I did have some Giant brakes that were a closed system.

Closed systems do not have an automatic expansion reservoir that the fluid can move into, and out of the main system, when it heats up and expands. An open system has such a reservoir. Almost all hydraulic disc bike brakes are open systems with the expansion reservoir as part of the brake lever (master cylinder) unit. . The problem with closed systems is that long downhill braking causes the fluid to expand, which causes the brakes to start dragging on their own, causing more heat and more drag, until the brakes lock up entirely.

Very very few 'closed' systems nowadays - any that are around are old. Even just standing a bike wit a closed brake system in sun could end up with pads jamming on as fluid expands in heat!

 

[lpretro1]

I think the OP means the difference between full hydraulic, mechanically activated (wired) hydraulic disc brakes.

OP did specifically say 'hydraulic'

 

[Pale Rider]

What happens if you don't replace the DOT fluid every 2-3years?.

On a bicycle, nothing, so there's no need to do it.

The brakes are under a lot more strain on a car, so periodic fluid replacement is advisable.

But once again, many cars brake perfectly well for years on end with the same fluid.

 

[summerdays]

On a bicycle, nothing, so there's no need to do it.

The brakes are under a lot more strain on a car, so periodic fluid replacement is advisable.

But once again, many cars brake perfectly well for years on end with the same fluid.

Good cos it's the same stuff in there since I bought the bike about 6 years ago, sludge or not they still appear to work well!

 

[Pale Rider]

Good cos it's the same stuff in there since I bought the bike about 6 years ago, sludge or not they still appear to work well!

QED, as is sometimes said.

Obviously, if your brakes ever needed bleeding it would be common sense to use fresh fluid.

I'm surprised the brakes on Mr S's bike need bleeding occasionally, most Shimano ones are fit and forget.