I have a bike with Ultegra Di2 with rim brakes. The rear brake lever is not snappy any more, I do not have a better word to describe it but even if the bike is braking alright the lever feels kind of hard.
All the LBS are saturated its incredible how their workload is so high in my area they are giving appointments months in the future so I want to try to repair it by myself.
What is according to you guys the issue, should changing the brake cable be enough? In case it is how complex is it to do at home?
Are they cable brakes? The cable could be sticking. You might also hear some sort of grinding noise. You could try detaching the cable from the brake caliper and moving it by hand (pull the brake lever, release it, and pull the cable back by hand from the caliper side). There shouldn’t be much resistance.
If the cable is sticking, it is better to change both the inner cable and the outer cable housing. How big a job that is depends on the cable routing on your bike.
Rear rim brakes are prone to grit grime and friction. You can get a feel for where is issue is by ‘feeling’ the lever. If there is a lot of tension required to pull the lever then chances are it is time to replace the cables. If when you release the lever it does not snap back it can be the callipers itself; you can also tell this by the calliper not fully returning leaving the cable slightly slack.
You may need to replace your brake cables. (Have them change both at the same time, it’s cheaper.)
Less likely, but if you use your indoor trainer a lot, your shifter mechanism may rust. (I’m not joking, this happened to me last summer, I could no longer shift properly, the levers would no longer return to their equilibrium position.)
The Shimano cables have a wax coating on them, the wax wears off local to a sharp change in direction, and the cable then starts to rough-up the inside of the outer at this point, that causes exactly the issue you’re describing.
Dont just change the cable, that will fix it for a while, but the damaged outer will cause the issue quicker next time.
Changing brake cables (and gear cables) at home isn’t a very complex task (can be a little trickier with internal routing) and is well worth learning to do yourself. Buying what you need in tools/cables will likely cost you less than one visit to the LBS to do the same.
A basic tool kit, some YouTube lessons and you should be doing basic bike mechanic work at home in no time
Before you replace the cable, I’d clean the caliper thoroughly with a toothbrush and lube all pivots.
If you detach the cable at the caliper, you could also remove the housing and give it a good flush out. Lube the inside of the housing and as much of the cable you can access and re-assemble. You don’t really need any skills to do this.
If it’s still not right, then you’re best to overhaul the cables and outers. If the brakes are due a change, you may as well do gears at the same time.
I used the Arts Cyclery videos on YouTube for how to set up gears for Sram Red mechanical. Brakes should be easy to do though.
If you do clean or lube your caliper, you will want to make sure you don’t get any of the fluids on the brake pads or your rim. It’s best to remove the wheel and pads before doing it. If you contaminate them, you might have seriously diminished braking.
Also, you should take this time to inspect your brakes in general. Check the condition of your pads and rim. Often rims have some indicators to tell you when they are getting worn through. For pads you can visually compare the depth of the grooves to new pads of the same model. You might also find pieces of metal or grit stuck in the pads.
