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Rim brake performance question

bmxboy10bmxboy10 Posts: 1,908
I have two rim brake bikes. My Supersix has DA callipers and Campy Eurus wheels and the braking is excellent. I like a lot of throw on the levers to give me more feel and the Supersix is nicely set up.

My Caad13 has 105 direct mount callipers and I run Shimano RS10 wheels on this bike. This is my not so good weather bike but still gets out on good days as I find the fit is perfect. The brake performance on this bike is censored even in the dry and I don’t know why. The lever throw is similar to the SS and both bikes have the pads slightly angled so they don’t sit flat on the rim face. I’ve cleaned the rims and pads. Do I need to try new pads or is this due to me using cheaper wheels? Any advice welcome.

Posts

  • wongataawongataa Posts: 945
    Brake pads make a big difference. Try better pads to start with.
  • photonic69photonic69 Posts: 1,251
    How much angle have you got on the pads? I found when I was a novice in setting them up I had too much angle and as a result there was less contact area (take pads out and see how much area is worn). I was using a the smallest cable tie (maybe 1mm) around the back of the pad as a gauge but this was too much. I now use a business card folded sharply and insert this on the rear edge as I clamp it up. Brake performance was increased dramatically.
  • MattFalleMattFalle Posts: 6,156
    try different pads and setting them up as above
  • First.AspectFirst.Aspect Posts: 7,460
    I never toe mine in at all. They either don't squeak or, if they do, I lightly sand the leading edge.

    Another thing to look for is whether the wheels are true and the brakes are centred. If your pads aren't engaging simultaneously, you will be putting effort into flexing the wheel.
  • bmxboy10bmxboy10 Posts: 1,908
    I’ll take another look
  • Munsford0Munsford0 Posts: 46
    I've never understood the whole toe-in thing with caliper brakes. Surely as soon as you brake the caliper flexes as it presses the blocks against the rim and they are no longer toed in? And if you routinely feather the brakes, don't you simply wear away the leading edge of the block so negating the toe-in setup?

    Disc brake pads - bikes and cars- are only ever presented absolutely parallel to the disc AFAIK.

    Anyhoo, I have 105 calipers with the standard Shimano inserts they came with, working extremely well on RS10 wheels*, so I'm at a loss to explain your poor braking

    *Christ, I've just worked out the wheelset is 13 years old! (East Anglia, rural leisure riding, lightweight shortarse who rarely brakes... )
  • bmxboy10bmxboy10 Posts: 1,908
    Munsford what you say about the toe in makes complete sense to me!

    Just popped to decathlon as they had the pads cheap. Swapped em over and all seems good so maybe the originals got contaminated.
  • photonic69photonic69 Posts: 1,251
    Munsford0 said:

    I've never understood the whole toe-in thing with caliper brakes. Surely as soon as you brake the caliper flexes as it presses the blocks against the rim and they are no longer toed in? And if you routinely feather the brakes, don't you simply wear away the leading edge of the block so negating the toe-in setup?

    Disc brake pads - bikes and cars- are only ever presented absolutely parallel to the disc AFAIK.

    If you think about it the front edge is closer to the rim. As you brake, the rim rotation pulls against the pads and flexes them to be more parallel with the rim. I think this helps with bedding them in more quickly and in my experience reduces brake squeal.

    Car brakes have highly chamfered leading and tailing edges - again to aid bedding in and reducing squeal.

    After a while it's all worn and bedded in nicely so doesn't really matter. The main thing is whatever you do is to get a good brake feel and efficiency that you are happy with, whatever method you use.

  • oxomanoxoman Posts: 9,731
    Different pads will help a lot. I use swisstop flash pro,s on my rim braked wet bike.
    Too many bikes according to Mrs O.
  • veronese68veronese68 Posts: 24,682 Lives Here
    I thought rim brakes were really simple and only hydraulic discs were complicated, shouldn't they all just work?
  • womackwomack Posts: 484

    I thought rim brakes were really simple and only hydraulic discs were complicated, shouldn't they all just work?

    They do on my bikes.

    No criticism intended to the OP but in general nowadays I just wonder if too much time is spent over analysing stuff and not enough time just riding the bike.
  • First.AspectFirst.Aspect Posts: 7,460

    I thought rim brakes were really simple and only hydraulic discs were complicated, shouldn't they all just work?

    Yes but they don't self-assemble. And some people have more mechanical intuition than others.
  • emanresuemanresu Posts: 279
    Hydraulic brakes are only considered complicated because they're newish and people need to learn a new skill. TBH bikes are fairly simple machines the most anybody who can follow a set of instructions can fix/maintain.
  • First.AspectFirst.Aspect Posts: 7,460
    emanresu said:

    Hydraulic brakes are only considered complicated because they're newish and people need to learn a new skill. TBH bikes are fairly simple machines the most anybody who can follow a set of instructions can fix/maintain.

    I've had them for a long time. Before that mechanical discs. They do run for a long time without needing work, but when they need work they are a pita. Consequently like a lot of people I suspect, I run them sub optimally to avoid the hassle.

    The most hassle I have ever had with rim brakes is the old pad not coming out.

    Discs are great for winter commuting. That's about it.
  • photonic69photonic69 Posts: 1,251

    I thought rim brakes were really simple and only hydraulic discs were complicated, shouldn't they all just work?

    Yes, they do just work as long as you have a cable, a caliper, some pads and a lever. However, even a Dura-Ace caliper if set up badly will under-perform. It's all about understanding the finer points and tuning it to perform at its optimum. I have a winter/commuter bike with discs. Yes, it works well in all weathers and it will no longer wear out my rims in the winter. But it does need fettling from time to time as pistons stick and the pads will rub. Over time I have had to buy the tools to service and bleed the system, though it is a minimal cost compared to other consumables like tyres etc.

    My summer bike has nicely set up 105 rim brakes with Swissstop BXP pads. Every time I get on it to ride I forget just how much I love the feel of the rim brakes over the discs. Much more feedback and a firmer feel. However I ride the disc braked bike more than the other, so it's like a nice treat when I do ride the summer bike.
  • MattFalleMattFalle Posts: 6,156

    emanresu said:

    Hydraulic brakes are only considered complicated because they're newish and people need to learn a new skill. TBH bikes are fairly simple machines the most anybody who can follow a set of instructions can fix/maintain.

    I've had them for a long time. Before that mechanical discs. They do run for a long time without needing work, but when they need work they are a pita. Consequently like a lot of people I suspect, I run them sub optimally to avoid the hassle.

    The most hassle I have ever had with rim brakes is the old pad not coming out.

    Discs are great for winter commuting. That's about it.
    this
  • MattFalleMattFalle Posts: 6,156
    emanresu said:

    Hydraulic brakes are only considered complicated because they're newish and people need to learn a new skill. TBH bikes are fairly simple machines the most anybody who can follow a set of instructions can fix/maintain.

    they're not really complicated, they're just a censored .

    lots of effort for something, well, not that high on the effort to reward ratio.
  • pilot_petepilot_pete Posts: 2,100
    They are simple. I don’t get what people feel is so hard about servicing a disc brake.

    Changing pads is quicker and easier than a rim brake bike. A quick wipe around the seals with a cotton bud and isopropyl alcohol will help stop the pistons sticking, which they can occasionally.

    Bleeding is quicker than replacing a rim brake cable inner and outer but granted not as quick as just an inner cable replacement though. Simply replacing the fluid every year or two with a bleed is not hard. That’s pretty much the only time you will need to bleed them once they are set up. No adjustment is required, they self adjust to allow for pad wear.

    Once set up correctly those are about the only jobs you need to do. Only other thing I can think of is occasional rotor truing, which again is not exactly challenging.

    As far as effort/ reward goes I think they pay back plenty. They work in all conditions equally well, which is a massive bonus with carbon rims and they don’t chew your alloy rims up by getting metal shards embedded in the pads or forming a grinding paste in the wet. Changing a rotor when worn to limits is much simpler, quicker and cheaper than replacing a rim, even more so with centrelock.

    So, they are not for everyone, each to their own, but they have been a match made in heaven for my bikes, all three with carbon rims.
  • I was a hater of discs but 100% convert .They need no more or less work than rim brakes .
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