jotaeh

My wife mentioned she thought her brakes were a bit weak, so I rode her bike and discovered that they weren't just weak, but REALLY weak. Compared to my own bike and my son's bike, her brakes feel mushy and have almost no stopping power. She has an 09 Cannondale Synapse 3 with Ultegra 6600 brifters and 105 5600 calipers. Wheels are Mavic Aksiums. Both front and rear brakes are equally bad.

I checked cable tensions, cleaned up the rims with isopropyl alcohol (99%!) and replaced not just the pads, but the shoes also with Dura-ace shoes/pads. I've also lightly sanded the pads. I checked the wheels for trueness, and I've adjusted toe-in from 1mm to 2mm to 3mm with no change in braking power.

So what I know now is:

It's not the pads or shoes, because they've been replaced with Dura-ace ones.

It's not the wheels; I put my Fulcrum 3 wheels and my son's Easton EA50s on her bike with no change in her braking power.

I'm at my wits end with her brakes... Can it be that the 105 calipers really aren't compatible with the Ultegra levers? (even though everything I've read indicates that it should be) I spoke to the mechanic at my LBS and he insists that the 105 calipers are "excellent" and should be giving good performance.

Does anyone have any ideas? Thanks in advance for any help!

FuzzyDunlop

How's the cable and housing? Any kinks or corrosion?

FastJake

My guess is the cables/housing were not installed correctly. Specifically where the cable enters the brifter. It's sometimes difficult to get the housing crammed in where it needs to be. If this was not done properly, the brake lever will pull at the cable and housing together, and very little braking will happen. Unfortunately, you need to unwrap the bars to check this.

See also Sheldon's guide on cables: https://sheldonbrown.com/cables.html

MNRon

I have 105 brakes on my bike, and my son's and they are working very well. I agree with the post to check the cables. Good luck, and let us know what you find.

MACAQUE

i also think the problem would lay within the brake lever...

reinstall w/ new cables and see how it feels...

Al1943

Try new cables and housings.
New Koolstop salmon colored pads wood also help.

davidad

The DA pads are the best you can get. Sounds like the cable housing needs to be replaced. Make sure that you use the housing for brakes. The der. housing will compress under load lowering braking force.

Al1943

The D-A pads that came on my bike were so hard that they were scraping metal off the rims and making scratching sounds. Worst I've ever owned. I replace all Shimano pads with Koolstops.

jotaeh

Thanks for the suggestions! The cables and housings are relatively new; installed about 3 months ago. I checked the stops and they're in the correct place. The housing is seated correctly... They appear to be brake housings (thicker than derailleur), but I'm gonna replace them anyway and see what happens... Got nothing to lose except the cost of new cables and housings!

well biked

+1

operator

Dura ace brake pads, up to and including the 7900 series suck. They contain an abrasive that destroys your rims.

Go buy some swissstops, or koolstops and then check all the housing, and make sure they are finished correctly. You might as well put on a new set while you're at it. If the brakes aren't centered properly, they will also feel 'mushy'.

LarDasse74

Adding toe-in will not increase braking power.

operator

Nope, it will decrease braking power and increase needed braking force through the lever.

frankenmike 

The only way to be sure the housing is correctly installed is to remove the tape up to the brifter. The housing needs to be seated all the way into the back of the brifter, just as fastjake says. If you have done this, I would try new pads as others suggest. FWIW, I personally like generic 5-10 dollar pads(Jagwire?) better than koolstops.

MikeWinVA

Shimano and Tektro pads are just awful compared to Koolstop.

In addition to having poor friction, they tend to pick up and embed every piece of crap that bounces off the road. I have also had good luck with Avid pads.

jotaeh

I replaced the cables and housings (new cables and housings) and checked for correct caliper centering (they were correct). Made sure the housings were correctly seated. Braking power is much better, but still a bit mushy, but overall, I think it's an improvement. Still not as good as the Ultegra 6700s I have on my own bike, but I think maybe the 105 calipers just flex more than the Ultegras.

BobLoblaw

105 brakes are excellent, certainly race quality, and that bike should be able to stop with confidence and authority. The difference in performance between 105 and Ultegra calipers is negligible, and Ultegra levers will pull those calipers just fine, so something is either flexing or broken between the lever and the caliper. Might be two ferrules mistakenly installed inside one another in the lever (sometimes those buggers don't want to come out and they're easy to miss), or it could be you need a ferrule and don't have one and the cable housing is pulling through along with the cable. Hard to say without seeing it, but those are things I'd check.

BL

jforman

Disconnect the cable at the front break. Squeeze the proper brifter. Note how much cable travel is evident. Compare that amount to the cable movement to you bicycle. (you do not have to diconnect your bicycle's brake because you know it works,) This will isolate if the problem is it the break itself or the brifter and oc connecting cable. If theamout of cable movement is similar, try compressing the disconnected break to see if is binding. also note how muchmovement that the break will do and how it compares to your bicycle.
If the problem is not in the break, isolate the cable and see if it moves. Or see if the brifter can actuate thecable. good luck

FastJake

Yep. If you can't lock up the rear wheel at will, and you can't lift the rear wheel with the front brake, you did something wrong. Those brakes/levers are definitely capable.

Kimmo

I'd try to get the brakes working decently before switching to Koolstops. 105 calipers should do the job pretty well with awful pads. There has to be a reason why they're not...

It sounds like the housings haven't been finished perfectly. A pic showing us their length on the bike might help too.

Thumpic

Have you moved the levers recently? Maybe you shifted them lower on the bar and have reduced the travel allowed/required to fully actuate the calipers?

wrk101

+1 I would get what you have working before throwing new pads at it. +1 My guess is housing issue, one of the ends not seated properly, or?

cyclist2000

Did you tighten the brake handles before putting the housing on the cables. sometimes the housing doesn't go to the very end and will feel squishy. do you have a ferrel on the end of the housing in the handle? I didn't on a pair of my sram levers and it kept moving the plastic cover back on the housing and didn't work well until I put a ferrel on the end.

HillRider

Are you certain of this? I remember years ago when 9-speed Dura Ace (7700) first came out, the brake pads were intended for use with ceramic coated rims, which everyone seemed to think were going to be universal on high end wheels. As such they were death on regular aluminum rims. Shimano got the word very quickly and changed the pads to a "normal" composition and, AFAIK, the problem went away. The Slowtwitch web site had a big article on this right after the problem pads were discovered and told how to tell them apart

I used Shimano OEM DA pads on one bike for several thousand miles with no abnormal rim wear. I did make sure they were not the ceramic type. Shimano had a dot code on the pads to separate the types. Koolstops are somewhat better but Shimano pads are by no means junk.

operator

I am certain.

My 7900 group came with their stock pads and their "improved" brake pad. It sucks. It started ripping chunks off into the pad just like crappy tektro pads, along with seriously reduced braking performance in the wet. They also contain AL oxide. Good thing we carry swissstop and zipp pads.