Tell me about these brakes

[Ajax Bay]

So the deduction is that if you wanted to go 'V'-brake ('cos familiar) you'd need new brake levers.

 

[T4tomo]

Where to start...

Firstly, degrees of freedom: height the post is set, height the straddle wire is set, angle of the calipers. Quite small changes in any of these these can make a big difference.

Secondly, none of these are easy to change and at least three hands are required to do them. Changing the blocks requires you to start again...

Thirdly, as the brakes wear, performance changes because the angles change as you tension the wire.

Probably other things too!

Alternatively, if you are sensible, you fit an in line adjuster into your cable run somewhere then it very easy to fine adjust on initial set up, and as and when your block wear a little. This has taken on a bit of thread drift from the OP, but seriously Cantis are not difficult to work with, provided you do a bit of research as to how they work before you start messing around with them.

 

[cyberknight]

So the deduction is that if you wanted to go 'V'-brake ('cos familiar) you'd need new brake levers.

mini v have pretty much the same cable pull so afaik you can get away with using the same levers ?

 

[Ajax Bay]

Yes, but this bike isn't going to have mini-Vs. They would cost way more than the bike. In fact if @Dogtrousers had any sense (which he of course has in great abundance) he'd get a right size and other specs bike from the local tip and scrub it up (in week to week free time before the canine pegs it) rather than try to 'get all he needs' and then go and refresh this bike many hours from home.
I tried to do this with a nephew's bike: it didn't end satisfactorily as there was always 'things' I didn't have 'with me'. If at home, all that stuff would be in my 'boxes'. Away. Nope (or take many boxes on visit).

 

[cyberknight]

Yes, but this bike isn't going to have mini-Vs. They would cost way more than the bike. In fact if @Dogtrousers had any sense (which he of course has in great abundance) he'd get a right size and other specs bike from the local tip and scrub it up (in week to week free time before the canine pegs it) rather than try to 'get all he needs' and then go and refresh this bike many hours from home.
I tried to do this with a nephew's bike: it didn't end satisfactorily as there was always 'things' I didn't have 'with me'. If at home, all that stuff would be in my 'boxes'. Away. Nope (or take many boxes on visit).

indeed . all i said was that mini vs have the same cable pull near enough so if someone did decide to change from cantis they could get away with the old levers

 

[Ajax Bay]

Cantis
"Cantilever brakes are unjustly considered to be poor brakes by many cyclists, compared to V-brakes for example. They do have their flaws, but low braking power is not one of those, it is mostly due to poor pad/rim material, and (more often) due to poor adjustment. Cantilever brakes allow the user to choose between stronger braking force, or shorter brake lever travel with weaker braking force. In short, these brakes have adjustable mechanical advantage,"
https://bike.bikegremlin.com/1739/cantilever-brake-adjustment/
This gives an insight (if desired) into the geometric theory, augmenting the Park Tools article linked upthread by @roubaixtuesday .

 

[Big John]

I've never over thought cantis because I reckon I've been lucky - once adjusted they always performed well. Today I discovered that I don't know as much as I thought I did so I'm going to read Ajax's link. I've refurbished a Raleigh Randoneur and took it out for its first test ride today to discover the cantis worked very poorly. The blocks have plenty of rubber left, new brake cables front and back and adjusted as I thought they should be adjusted but sadly you'd have thought I'd oiled the blocks. These are Deore cantis so not exactly rubbish and have plenty of spring in them. I'll see what Bike Gremlin have to say and what I can do to improve matters.

Edit : looks like it was me and not the cantis. At least I know pretty much why they're performing so badly. Tomorrow morning it's fettle time. Thanks Ajax for that useful link.

 

[fossyant]

Thanks. May be a dumb question (I know nothing about these brakes) but those pads look to be quite a bit longer than the ones fitted. Does this matter at all?

No, but they aren't as deep, so will track the rim better.