why to halford charge £4.99 for 125ml of mountain bike dot 5.1 and £5.29 for 250ml motor vechile dot 5.1, is there a difference of is it a rip off mountain bikers policy

Also when you ask an assistant where the dot 5.1 is they don’t mention i can buy it cheaper if i walk 5 yards to the motor vechile isle

why to halford charge £4.99 for 125ml of mountain bike dot 5.1 and £5.29 for motor vechile dot 5.1, is there a difference of is it a rip off mountain bikers policy

Also when you ask an assistant where the dot 5.1 is they don’t mention i can buy it cheaper if i walk 5 yards to the motor vechile isle

You’ve probably still got time to make that make sense.

So the motor vehicle Dot 5.1 is 30p more expensive? Or am i missing something?

Dot 5.1 = Dot 5.1

£4.99 for 125ml of mountain bike dot 5.1 and £5.29 for motor vechile dot 5.1

sounds like rip off car drivers unless my maths is wrong.

😉

school boy error

the car stuff will be a much bigger bottle

but the problem is it goes off so unless you have a load of brakes to bleed in a relatively short space of time a big bottle is little use

the car stuff will be a much bigger bottle

Thanks, Captain Obvious.

Ninjatune spotted it, everyone else has failed.OP even lists the bottle sizes.

but the problem is it goes off so unless you have a load of brakes to bleed in a relatively short space of time a big bottle is little use

how long does it last?

maths and reading required

£4.99 for 125ml of mountain bike dot 5.1 and £5.29 for 250ml motor vechile dot 5.1

125ml = £4.99 in bikes aisle
250ml = £5.29 in car aisle

30p more for twice as much is the point I think……

EDIT – rats beaten to it by slow typing!

Is this really a Halfords rip-off or a common sense failure?

The volume of the motor aisle bottle was added later in an edit. Though it was obviously a bigger bottle, was just taking the michael a little bit cos of the mistake in the original post.

But it’s lucky all you smartslow guys are around.

You can’t keep that much Dot fluid around for long anyway – it’s hydroscopic so will eventually absorb spongy soft water molecules, eventually leading to you shoving it up your brakes and wondering why you have spongy brakes.

Anyway, they probably come from different suppliers and the trade price is higher for the bike stuff.

Simples.

Plus, it’s only £4.99, you can make a wish with the left over penny. Maybe for a fairer society.

how long does it last?

The problem is that once it is opened it can absorb moisture, it then loses it’s resistance to heat and the water in the fluid can boil and cause spongey brakes. how long it lasts depends upon the conditions in which you can store it. Somewhere cool and dry it will last longer than somewhere warm and damp.
Unfortunately you won’t know if it has gone off until you are hooning down a descent and you can’t stop cos your fluid’s boiled.

Surely you got taught economies of scale in school?

Halfords will sell sh*t loads of bottles intended for cars.

But the bottles with “mountain bike brake fluid” on them will sell at a tiny fraction of the car stuff thus the costs of bottling/branding/marketing the bike branded stuff will be higher for the supplier and Halfords wont be buying it in at high volume.

There is no point most people buying a large bottle as glycol based brake fluid absorbs moisture from the air so you should only use a new bottle.

People who know a little bit about brake fluid will know that bike Dot 5.1 is the same at car Dot 5.1 so they will go buy the smallest bottle of the car one they can. People who don’t will go and pay a little bit more per ml for the reassurance they are getting the right stuff. As you should not store a bottle once opened they are not really spending any more if they buy the bike stuff as they will just be throwing less away and not causing so much chemical waste.

Also I don’t really see the point of dot 5.1 in a bike. Dot 4 should be fine (but if the brake manufacturer says use 5.1 then use 5.1).

Personally I prefer Dot 5 if your brakes can use it as it is silicone based or mineral oil if they are designed for it instead as neither absorb moisture so you can buy a nice big bottle of stuff intended for car/hydraulics use.

PS you are a wally going to halfords for it anyway. Go to a local motor factors and you should pick up a small bottle for less than £5.

eg Dot 4, 300ml £1.60! http://www.eurocarparts.com/ecp/p/car-accessories/engine-oils-and-car-fluids/auxiliary-fluids/brake-fluid/?524770031&0&cc5_179

You can’t keep that much Dot fluid around for long anyway – it’s hydroscopic…

It’s hygroscopic. Furthermore, the problem is that moisture lowers the boiling point of the fluid, not that water molecules are spongy.

Ha, awesome. You learn something new everyday.

People must think I’m a cock at work, I’ve been saying Hydroscopic for ages.

the old adage rings true:

“Arguing on the internet is like being a contestant in the Special Olympics.

You may win, but you’re still a retard.”

^^^ aye (@ three fish)

+ water in fluid can promote corrosion of internal parts – damage to pistons and preventing bleed nipples and hoses coming undone. That is more a concern for cars though.

I always tell people working on cars to buy lots of small bottles so you minimise what you have to throw away. If doing a full bleed then yeah buy a 1 litre bottle but buy a few smaller ones – 500ml, 250ml etc for finishing off and keeping a spare.

People who don’t will go and pay a little bit more per ml for the reassurance they are getting the right stuff.

I once had a guy in the shop insisting that he wanted a genuine Cateye battery for his cycle computer. When I suggested that the local jewelers or camera shop would be able to supply him with a replacement he gave me a look that made it quite clear I wouldn’t be seeing him again.

OP even lists the bottle sizes.

have a look at what bigjohn and i quoted up there ^.

@ Mostly balnced – that’s totton for you 😉

Cateye battery! lol

And he doesnt realise that oem batteries are bought from the cheapest asian supplier and rebranded. Oh well, people like that help reduce costs of equipment for the rest of us by paying far too much for branded consumables!

I buy the larger bottles of 5.1 from Halfords. I only use about half of it for a full bleed of F&R brakes so then I squeeze the bottle until the fluid is level with the top and then screw the top back on. I don’t know if this stops it from ‘going off’ but i don’t have any trouble with my brakes.

^ that will help. But for my car I do’t take the risk.

What if you keep your DOT fluid in a sealed bag, along with some sachets of silica gel, in the freezer?

I don’t: haven’t used DOT fluid brakes for years, but just wondering…

As long as the top is kept on brake fluid can only absorb any moisture from the air in the bottle. Kept in a sealed bottle its shelf life is indefinate. Constantly opening and closing is te only way it will degrade to a noticeable point.

Andyl, what brakes can use Dot 5? I was assuming you meant 5.1 but reading through, you do seem to mean Dot 5, which is not compatible with Dot 4 or 5.1 systems, or mineral, so I’m not sure where you’d use it?

Perhaps we should re-label the “edit” button, something catchy like “make everyone (including me) look a fool” button would be more apt:)
Edit-used it myself to add the bit about bottle size in the OP, wondered why nobody else had noticed.