Werkin

SwissStop BXP (blue) pads will improve both power and modulation with any rim brake on aluminum rims.

Shimano 6800 and 9000 series brake calipers are not like traditional dual pivot center mount calipers. Each of the arms are equal lengths, the pivots are closer to the brake track, and they have other features that offer true advantages over traditional dual and single pivot center mount calipers. Power is on par with v-brakes, but they excel in modulation. Their stock pads provide outstanding power with both model specific lever ratios and other ratios from shorter pull levers. Modulation with the stock pad suffers somewhat when paired with shorter pull levers, SwissStop blues can fix that. The newer model levers are long pull/low mechanical advantage levers, and the calipers have high mechanical advantage. When using short pull/high mechanical advantage levers like early Shimano, or SRAM, Tetkro, and Campagnolo with these type calipers, the pads require a shorter gap to the rim initial positioning to maintain power in the meat of the lever pull before lever touches bar.

canam73

I'm curious what you mean by 'power'. Do you actually have difficulty setting traditional forged dual caliper brakes with decent pads to be able lock the wheels, which is what I would consider "full power"?

I'm not saying you want lock up when braking, just that any power past that is irrelevant, and at that point it becomes all about modulation.

Werkin

Modulation is user control up to and including the threshold of lock-up. Power in my description can be defined as low lever effort required for rapid slowing. A stick in the spokes can lock a wheel, so what.

canam73

Ok, I'll restate: Do you actually need a lower level effort for rapid slowing than traditional forged dual caliper brakes with decent pads give?

I'm actually am wondering as I haven't seen this be an issue, even on my wife's bike which has Tekro calipers and a shim in the lever to reduce reach. Pads are the KoolStop black which came with the calipers, cable and set up done my myself with a Jagwire Racer kit. Rims used were originally some Shimano R560 wheels and then replaced with home builts with Kinlin XR300s.

Dave Mayer

You seem to know about these brakes, so here is my burning question. To start, bicycle brakes are very simple machines, in which the action of the hand lever is translated into travel of the caliper arms. The mechanical advantage of the hand lever is multiplied by that of the caliper. So you have to look at the system as a whole.

You can build a braking system with higher mechanical advantage; things being equal this equates to more stopping power. But this comes at the cost of more lever pull, or having to run the brake pads closer to the rims, or both. Plus modulation suffers with higher mechanical advantage.

So can you tell me if the total Shimano 6800/9000 system has more or less mechanical advantage than the older dual-pivot braking systems?

I have briefly looked at the linkage of these brakes. They are basically centerpulls, with the arms linked to force self-centering of the 2 pads.

I can see the advantage of each of the 2 caliper arms being directly and separately mounted to the fork or frame. Just like the old touring bike centerpulls. Potentially less flex. I think Shimano has a version of these that are direct-mounts. But the standard version of these brakes, for mounting on convential frame fittings are more like the old Mafac centerpulls. In this configuration you lose much of this advantage. I rode on Mafac's for years, and had some scary moments trying to stop.

More insights please..

Werkin

More mechanical advantage than traditional side pull/dual pivot calipers.




I don't have an image that shows the center bearing and cam finger close-up, but caliper arm leverage can be adjusted somewhat via an adjustment screw that alters cam finger arc. It is an additional leverage and arm angle feature which can increase advantage, plus allows for equal leverage on varying rim widths. I used this adjustment to improve modulation that was compromised by combining a high mechanical advantage lever (Microshift) with high mechanical advantage caliper (BR-9000). Reduced power was not the problem with the mechanical advantage mismatch, power was just ramped abruptly. I had very good results with the 9000 cable set, quality housing and the polymer-coated cable made a noticeable improvement, and as stated earlier, SwissStop blue pads brought back modulation. In the beginning I enjoyed the hippopotamus bite of the stock pads.

Smokehouse

Mechanically, the 6800 is a better design/build than the 5700/6700...the differences are immediate when you look at them. Actual performance wise, the stinking weather has been absolute crap so I STILL haven't been out with them. I do look forward to putting them through their paces...eventually...

nitewing117

@Smokehouse
Sorry for the thread revival (I don't have enough posts yet to PM..). Do you have any updates with the 6800 brake/5700 shifter combo?

Smokehouse

sure! I ran them all season '14 and had no problems with that combo (6800 brakes, 5700 shifters). Recently swapped to 5800 components (save the brakes) and the 6800 brakes work just as well with the 5800 shifters. Truth be told, zero difference in performance...they work just as well either way.

nitewing117

Great! thanks for the info. Looks like I have another mod to add to my list..

dtrain

I'm running 5800 calipers with 5700 STI's (on one bike). No problems, and much better performance than the stock Tektros. The other bike is full 5800 and the braking feels a bit nicer (so I think some feel is in the cable/STI).

bt

when did these come on the market?

andr0id

I replaced the 6600 group on my Waterford with 6800 a few months ago.

The brakes are the cat's meow, very noticeable improvement in power and feel and just damn solid feeling.

The shifting also seemed more precise, but... that could just have been because my old group had a lot of miles on it. So I would shift and then have to nudge the lever to get it to drop in.

The upgrade is not earth shattering, but definitely better.

jaxgtr

Whoops....meant to say 6800.

JohnJ80

I did this too.

When I upgraded from 10 to 11 speed Ultegra, I was looking for better shifting that 6800 offered but I got a deal on the group set and wanted the brakes to match (color). The brakes were the big performance surprise. Really like the new brakes and am glad that I put them on. Modulation is much better.

J.

Campag4life

6800 brakes as the best I have used and run them in fact even on my Campy bike...same pull ratio and work great with Campy levers.

macca33

I concur, the 6800 series brakes are quite a deal better in use, compared to 6700, 5700, 7800 series I've had previously.

cheers