Best Long Drop Callipers?

Nuggs

Hi Gang

My winter bike currently has some horrible low-end Shimano long drop callipers fitted. I know the stopping power of long drops is going to be less than standard stoppers, but they really are pants.

I can't replace the pads with anything better (e.g. Koolstop Salmons) as the pad holder is the wrong size. I could bodge them in, but I wll crap my chamois every time I'm flying down a hill thinking 'I hope those pads stay in place so I don't come a cropper'...

So - any suggestions as to the best Shimano-compatible long drop stoppers around?

Ta!

hopper1

I have Shimano 6500's.
I wasn't too impressed with first use, it was wet! :shock:
They seem to have settled down now (bedded in) and aren't too bad.
The other thing hindering their effect, is that I'm using Shimano Ultegra 6700, which evidentally has a different pull ratio... :roll: :oops:

balthazar

I don't have any to check, but do long drop brakes not have proportionally longer lever arms (to the cable stop and pinch bolt), in order to keep the overall mechanical advantage the same?

If not, why not?

hopper1

balthazar wrote:

I don't have any to check, but do long drop brakes not have proportionally longer lever arms (to the cable stop and pinch bolt), in order to keep the overall mechanical advantage the same?

If not, why not?

I've just returned from my very cold garage and can confirm that both my long drop(6500's) and my normal (Sora's) have a distance of 45mm between the two points you mention.
My SRAM Force, on the otherhand, are 50mm... I wish SRAM did deep drops... :idea:

Slow Downcp

What is the drop that you actually need? You may be able to get away with a paid of standard callipers, and carefully drill out the arms slightly to allow greater drop.

Or get complete salmon pads and holders rather than bodge pads into the wrong size holders?

Nuggs

Slow Downcp wrote:

What is the drop that you actually need? You may be able to get away with a paid of standard callipers, and carefully drill out the arms slightly to allow greater drop.

Or get complete salmon pads and holders rather than bodge pads into the wrong size holders?

No standards don't work, it's a TK2 frame with SKS guards and they really do need the extra length.

The Kool Stop holders (in common with DA holders) use a different bolt to my callipers (M6 as opposed to M5 IIRC), so to fit them I'd need to drill out the calliper, which I'm not too keen on...

balthazar

hopper1 wrote:

I've just returned from my very cold garage and can confirm that both my long drop(6500's) and my normal (Sora's) have a distance of 45mm between the two points you mention.
My SRAM Force, on the otherhand, are 50mm... I wish SRAM did deep drops... :idea:

Ah. I wonder if in the cold you measured the wrong thing; it's not the distance between those two that matters, but the lengths of the levers which join each of them to the pivot (In the case of dual pivot brakes – now the norm – each lever is a different length). In other words, do they stick out further to the side.

Don't worry about it though, I'm sure everybody's right, it just seems an oversight on the manufacturers' part, unless I'm missing something.

EDIT: after a quick dive into Photoshop, here's a diagram:


If Distance BC is lengthened, why isn't AB increased to match?

keef66

I got Shimano long drops on my Tk and they seem to work pretty well with the supplied all-in-one moulded Shimano blocks. Was planning to upgrade to Koolstop salmons when required, but you've made me think that perhaps I can't.

Nuggs

keef66 wrote:

I got Shimano long drops on my Tk and they seem to work pretty well with the supplied all-in-one moulded Shimano blocks. Was planning to upgrade to Koolstop salmons when required, but you've made me think that perhaps I can't.

I'll take mine apart tonight and let you know how I get on!

hopper1

Not that I'm bored, or anything... The first figure is for deep drop, the second is off my Sora



The deep drop do appear to be slightly larger.

balthazar

hopper1 wrote:

Not that I'm bored, or anything... The first figure is for deep drop, the second is off my Sora



The deep drop do appear to be slightly larger.

That's just what these forums are for isn't it? Abstract noodling about obscure technical nonsense?!

The weird thing is, your deep drop brakes seem to drop less than your normal ones: 55 vs 65 mm on one side, the same (40mm) on the other. I don't get it.

But, from looking at pictures of brakes online, I get the impression that deep drop brakes are often wider than normal, meaning their MA is probably about the same. In that case, there's no reason to expect their braking power to be any less than normal. Have a look at some here.

hopper1

balthazar wrote:

hopper1 wrote:

Not that I'm bored, or anything... The first figure is for deep drop, the second is off my Sora



The deep drop do appear to be slightly larger.

That's just what these forums are for isn't it? Abstract noodling about obscure technical nonsense?!

The weird thing is, your deep drop brakes seem to drop less than your normal ones: 55 vs 65 mm on one side, the same (40mm) on the other. I don't get it.
But, from looking at pictures of brakes online, I get the impression that deep drop brakes are often wider than normal, meaning their MA is probably about the same. In that case, there's no reason to expect their braking power to be any less than normal. Have a look at some here.

I did check that, and couldn't fathom it myself :oops:
I'm pretty sure mine feel weak because of the new pull ratio of the 6700's, same as DA :evil:
I think maybe the 'deep drop' is formed in the bridge area of the calliper, ie: from centre pivot to cable stop/ side pivot, therefore the drops, on the sides are the same as standard. I hope that makes sense... :oops:

also, just noted that it's possible ( I didn't check!) that the fixing point for the two different braking systems are in different positions in relation to height above tyre, and when measuring to point 'C', these are brake blocks and therefore adjustable, depending on rim types, etc...
Getting confused, now...

balthazar

hopper1 wrote:

I hope that makes sense... :oops:

Yeah I think I know what you mean. The geometry of these things is complicated – do you take an average of the MA of each side to establish the overall MA, or is there a more subtle way of calculating it? I suppose one could just measure the amount of pad travel for a given amount of cable pulled. The more I look at dual-pivot brakes the uglier I find them, for the compromised way they function.

also, just noted that it's possible ( I didn't check!) that the fixing point for the two different braking systems are in different positions in relation to height above tyre, and when measuring to point 'C', these are brake blocks and therefore adjustable, depending on rim types, etc...
Getting confused, now...

The fact that brake blocks are adjustable vertically has always been a factor in overall MA. I suppose the way to account for it is to treat C as a consistent point, ie. the bottom of the slot.

hopper1

Aye, get some 'V' brakes... :roll: