I'm going to get some new wheels and disc brakes from Merlin soon, as they have a good reputation and are my LBS anyway.

But should I go for the Formula B4 sport or the Magura Julie discs? The Formulas are quite a bit lighter than the Maguras.

Third option is to go for the formulas but if I find that they lack power to get an adapter for fitting a bigger disc to the front.

So has anyone used the Formulas?

The majority of my use will be bridleways etc

out of the 2, i'd take the julies... very nice little brakes them, pretty much foolproof and trouble free.

i'm sure someone will be in telling stories about the formulas soon enough.

I've been using B4s for over a year, very pleased.
Enough power I've found as standard though it may depend on your weight and the sort of terrain you ride.

Chalk up two votes for the Julies. Totally fool-proof (even I can fit and use them!), and they come ready bled and with a 5 year warranty. Be rude not to!

Merlin were doing deals on Julies and disc wheels The julies were the new 2005 version

I've got formula B4s on my hardtail, Hayes on my full sus & my wife has Julies on her hardtail.

Formula B4s are lightweight XC brakes which work very well, but I've had to bleed them 3 or 4 times in the 18 months I've had them. Standard sizes are 160mm front, 140mm rear so don't try downhilling on them.

The Julies are a bit bigger with wavey rotors, but I can't speak for their stopping power or reliability. They haven't broken yet, but she's only had them since about March.

The Hayes are fit & forget items, unless something goes wrong - apparently parts are hard to come by (allegedly). So far they're great.

At the end of the day, it probably boils down to how much you want to spend - you should be able to get the Julies for abuot £150 (front & rear), B4s for £190 f&r, Hayes £200 f&r

My main reason for fancying the Formulas is the considerable weight saving over the Julies.

As for price, theres not much in it, both including wheels (Deore / Mavic 717) Formulas are £200 and Julies are £185.

As I said my main use is bridleways etc, which I suppose do go up and down, but not normally too dramatically. They are going on a hardtail BTW.

To be honest Matthew you'll find the weight saving pretty marginal in the long run. On the basis that you're doing most of your cycling on bridleways (not racing at all, I presume) and generally pootling about, I would suggest that you'll actually welcome a marginal weight penalty over having to bleed the brakes every 4 or 5 months.

go on, admit it, it's the bling bling gold colour, isn't it ;-)

oh, yes, another thing about the B4s. The brake lever is connected to the master cylinder with a small 'dogbone', which is designed to pop out in a crash to save damage.

Watch out for losing it in said crash.

(I haven't lost one yet, but one of my mates has B4SLs & we spent about 10 minutes on a night ride once looking for his dogbone in the dark, snowy, wet, muddy slush)

"go on, admit it, it's the bling bling gold colour, isn't it ;-)"

The ones I looked at in the shop weren't actually Gold they were Grey/Black. A bit of colour (gold) would break up the slightly monochrome effect you get with a polished silver frame though.

Actually, I think that's the old colour... mine are gold anyway - B4Team

But the gold would clash with the polished aluminium, wouldn't it? ;-)

Don't get me wrong, I like the brakes, and I'd probably buy them again, but I have had a couple of niggles with them. They've been ok for the last 12 months or so, no bleeding required, or anything else for that matter.


But then I don't always ride the hardtail, so they're probably only getting half the use they used to do