Hi all, maybe a newbie question but I have some ‘giant mph’ brakes on my xtc sx but the levers are both bust. Can I fit different levers? I’m looking to buy off net a cheap pair as money is tight??

probs not

Probably not, you need to match up the brake fluid type, and get a roughly equivalent piston size/volume, and you’ll need to figure out hose connections which may add cost. Also, buying levers seperately tends to be expensive.

Sometimes. First thing to consider is mineral or Dot4/5 oil.

PS: i have Magura LouiseFR levers & Marta SL calipers and all ok (all Magura kit but different gnarr ratings).

ignore the doom mongers, they are giving typical STW answers (which means I have never done this before, have no actual idea if its practicable, but I think you should hear my opinion anyway).

I’ve done it, often. So yup you definitely can, as long as they are designed to take the same type of fluid.

ie

dot4 and dot 5.1 are mixable

but dot 5 needs to be kept away from any dot 4 or 5.1 ..

Other than that, there is a theoretical variance with performance due to issues with differences in the ratio’s of the lever piston dia and the caliper piston dia, but Ihave never found it to be a problem and I doubt you will find it to be a problem.

The other issue is hose fittings, but I think superstar do after market hose kits where you can choose the fittings..

Given all this, have you considered flogging the mph’s (they fetch good money even when broken) and buying a pair of deore or avid elixir 3/5 which will probably work out even money by the time you have sourced replacement levers, sorted the hose fitting issue and spent money on brake fluid/bleed kit to get it all working..

Not to those brakes- they are a “closed” system. This means that when the pad wears down you have to turn the dial on the handlebar to make up for the extra amount the piston must move. An “open” system has a rubber bladder that fills the void automatically and so you don’t have to do this.

Every brake available now is an open system and it’s unlikely the brakes will work as they were designed to with other levers.

toys19 – thanks for the info.

Given all this, have you considered flogging the mph’s (they fetch good money even when broken) and buying a pair of deore or avid elixir 3/5 which will probably work out even money by the time you have sourced replacement levers, sorted the hose fitting issue and spent money on brake fluid/bleed kit to get it all working..

I reckon i’ll do what you recommend and stick them and get me some deore m596’s instead.
Everything considered that is probably the best (and easiest) thing to do!

Cheers guys

Thanks munrobiker

Not to those brakes- they are a “closed” system. This means that when the pad wears down you have to turn the dial on the handlebar to make up for the extra amount the piston must move. An “open” system has a rubber bladder that fills the void automatically and so you don’t have to do this.

When you say it like that it makes a lot of sense.

munrobiker – I first did this on giant mph’s as they levers constantly failed. Worked fine with some early levers with rubber diaphragms (I think it was crappy plastic julies, but cannot be sure).

Closed and open system brakes only differ at the lever(master cylinder), calipers are calipers (slave cylinder).

You could try looking for an old set of Hope C2’s – the Giant MPH is a licensed copy of the C2, so the levers are probably interchangeable.

Difficult to get new, though – Don’t think they’ve been on the market since 2002 or so!

There is great thread here with some budget brake ideas

http://singletrackworld.com/forum/topic/decent-budget-hydro-disc-brakes

not really much point going on about dot 4, 5, 5.1…the biggest consideration is Car type (ie dot 4 compatible) or mineral oil.

eg Avids use Dot 4, shimano use mineral oil. The materials inside will be selected for the oil type so you cannot mix and match these.

As for wear adjustment – surely this is all down to the lever as the caliper is the dumb (slave) part. If they use dot 4 then I’d be tempted to try them with some old Hope or something cheap and easily got hold of like Avid Juicy 3 levers.

not really much point going on about dot 4, 5, 5.1…the biggest consideration is Car type (ie dot 4 compatible) or mineral oil.

eg Avids use Dot 4, shimano use mineral oil. The materials inside will be selected for the oil type so you cannot mix and match these.

well actually there is, as what you have said is essentially an incomplete version of what I said above. Avids use dot 4 or 5.1. Shimano use dot 5.

Mineral.That’s why they go to the trouble of printing it into their lever parts :O)

well actually there is, as what you have said is essentially an incomplete version of what I said above. Avids use dot 4 or 5.1. Shimano use dot 5.

erm no they don’t. Shimano use MINERAL oil which is not dot 5. Dot 5 is silicone based.

Dot 4 and Dot 5.1 are almost the same and fully compatible.

Dot 5 is silicone based and while is normally compatible with dot 4/5.1 systems you need to fully clean out the system first and it is expensive.

Mineral oil is completely different and similar to the hydraulic fluids used in things like Citroen suspension but Shimanos fluid is very low viscosity.

My reason for saying there is no point in going on about dot 4, 5 and 5.1 for bike brakes is dot 4 is pretty much the main one you need to worry about as dot 5.1 is fully compatible and I’ve never seen dot 5 (there may be some brakes somewhere but I’ve never seen any).

No worries, you believe that if you wish.

Dot 5 is silicone based and while is normally compatible with dot 4/5.1 systems you need to fully clean out the system first and it is expensive.

Whilst yes mineral oil is not silicone based like dot 5, they can mix and you can use them interchangably, but please don’t go saying that you can mix dot 5.1 with dot 5 because thats just bollocks.