Mr IGH

This is a purely cosmetic question. My 1978 AD Inter-10 frame has 57mm brake reach right on the button. I'm running a set of Tektro super-long reach 559s (55mm~73mm reach) with the pads all the way up . I have a project that requires a set of the 559s so I could buy some Tektro 539 (47mm~57mm) for the AD and run the pads all the way down.

I have always liked the look of pads all the way up, I tempted to leave things as they are and buy another set of 559s for my project.

Any comments are welcome.

fietsbob

Typically a range is offered .. answered it yourself.. as you are writing..

(47mm~57mm) means slot is a CM long.

There are Brake pad holders that add a Little more offset..

A trifle of MA is gained with pad at the top since it's closer to the pivot.

(my Ideal is in the center of the slot. , but it's not up to me because I made neither the frame or the brake.)


/

John E

If you ever might want the ability to use smaller-diameter rims, you will want the pads all the way up. Conversely, if you ever might want larger-diameter rims, you want to be all the way down. Otherwise, it does not really matter.

Mr IGH

Thanks for the replies. The choice is binary, all the way up, all the way down. Wheel size is 700c and will never change.

It's just an cosmetic question; given the choice, all the way up or all the way down?

repechage

As you are discussing dual pivots, I would look at the pivot locations. Closer to the pad is in general better mechanical advantage. The longer reach caliper MAY have different pivot placement, maybe just longer arms below the pivots.

T-Mar

If you select the caliper where the pad is positioned at the top of the adjustment range, the caliper should also be marginally stiffer.

noglider 

I was thinking of saying the same thing, though I bet the difference isn't discernible. Calipers seem to be stiffer these days, and that's a good thing. I once installed no-name long-reach dual-pivots on a bike, and I was impressed.

T-Mar

The difference probably isn't noticeable, except under controlled conditions, but it is accepted. During the boom is was not uncommon for frames to be designed with 10-15 mm of additional reach on the rear. Typically, this practice was used on entry level bicycles, where inexperienced cyclists tended to employ equal hand pressure on both brakes, especially in panic situations. The longer reach brake flexed more, decreasing the tendency to lock the de-weighted rear wheel. In the 1990s, Campagnolo specifically started to design increased flex into their rear calipers for this purpose.

Wilfred Laurier

The statements above that the difference in leverage or brake power per unit hand force is a 'trifle' better, or 'probably isn't noticeable' are incorrect in my experience. The percent difference in leverage is equal to the percent difference in distance from the pivot to the pad. The distance to the top of the slot is never more than 20 or 30 mm, but the adjustment range is generally about 20mm, which could be between 60% and 100% difference in leverage.

I know that this is not what OP was asking, but it deserves mentioning.

Andy_K 

Apart from the placement of the pads, I like the look of the R539 better, but I'm probably in the minority in this group because the styling of the R559 is more like vintage brakes.


Otherwise, my vote would be for all the way down.


As for leverage, the R539 performs really well with the pads all the way down, and I say this as someone who likes a lot of leverage in my brakes. I haven't used the R559, so I can't say how it compares. Looking at pictures, it looks to me like the R559 has more metal between the pivots and the start of the slots, so I doubt there's much difference between an R539 all the way down and an R559 all the way up.

JohnDThompson 

You'll have slightly better mechanical advantage with the pads all the way up.

T-Mar

While it's substantial on paper, can the average cyclist detect it in a real situation, without controlled conditions and measurement? The C&V membership is probably far more sensitive to this sort of thing, yet of the hundreds that have converted from 27" to 700C, I don't recall anybody commenting on the difference. A full pad drop will result in 3 to 4 times more difference than the conversion change but the average cyclist isn't as discerning as forum members and probably still wouldn't notice the difference in everyday use. Maybe I'm not giving the average cyclist enough credit but based on the bicycles that came though the LBS, most are blind to anything other than a catastrophic change.

jimmuller 

Huh (to a lot of what I see here)? The MA would vary with pad position only if the distance from pad to pivot changes. But the pad position is determined by the rim location, and the pivot is where it is from the brake design. Maybe the different Tektro models have their pivots in slightly different places, but I wouldn't bet on that without measuring.

So what else could be different? Well, JDT's comment might have some substance for this reason. If the pad is at the bottom of the range, the slotted part of the arm above the pad could be a bit more flexible than if the part above the pad were solid. So maybe the longer arm would be a bit stiffer. The existence of more arm, slotted or not, beneath the pad has no affect at all.

If the arms are longer than necessary you add a few grams to the weight.

Since you asked about aesthetics, I prefer the shorter arms. I doubt you could feel any difference in the two models.

Grand Bois

Pads all the way up or all the way down looks odd to me. I like them at or near center. That makes it a little harder to choose the right brakes, but that's okay with me.

Pads all the way up looks like I bought the wrong brakes. I replaced them with Weinmann 500's.

Wilfred Laurier

I would bet the vast majority can feel it, but consider the change to be within an acceptable range. Also, people who are not familiar with the hows and whys of bicycle function are probably used to their brakes decreasing (and less often increasing) in power for reasons they cannot fathom - oil or other contamination on the rims, cables in poor condition, worn or aged pads ... I have seen comments on this very website that claim a similar change from changing from mtb to road disc calipers (with long pull levers) is not a problem because "the brakes still work fine - you just have to squeeze the levers twice as hard."

I have done a few 27-700 conversions and always been astonished at how weak the brakes were after. More than once I went from 27" chrome steel rims to 700c aluminum rims, brake pads adjusted but all other variables kept constant, and experienced no increase in stopping power. Swapping from 27" aluminum to 700c aluminum rims makes a definitely noticeable decrease in stopping power.