Originally Posted by
elcruxio
I'll assume you mean a bicycle front wheel cannot skid on clean dry tarmac type surfaces whilst riding forward?
That’s the most common one, yes. However in nonstraight ahead situations, locking the front wheel won’t result in a good outcome. A nonspinning wheel is unstable. That’s why a skidding rear wheel tends to move from side to side during a skid.
If you could skid the front wheel, it would do the same and the rider is going to have difficultly staying upright.
Originally Posted by
elcruxio
This is one strange difference in people. I've been quite impressed lately by the control and modulation I get from my hydraulic disc brakes. Takes a bit of fiddling to get the one finger position setup properly but once that's done I'd wager the four piston hydraulic brakes I have on my fatbike are the most precise brake system I've ever ridden. I can do manuals with them, which hasn't ever been possible on any rim brake system or even mechanic disc brakes.
It is a strange difference indeed. By “do[ing] manuals”, I assume you mean nose wheelies. That’s not a measure of modulation in my opinion. It may be a measure of power but I can lift the wheel of just about any bike I own with just about any brake own.
Originally Posted by
elcruxio
And then on the other side of the coin are vee brakes which are truly on/off with very little modulation in between. Very powerful yes, but also very dangerous as it's just way too easy to lock up the front wheel.
I don’t know what brakes you have used but I’ve used a lot of different linear brakes. I work on a lot of linear brakes on other people’s bikes. I’ve never experienced one that is as you describe. Nor have I ever had anyone at my bike co-op complain about linear brakes being to grabby.
I have experienced hydraulic brakes that are digital...the opposite of good modulation...with exactly the on/off quality you describe.
Originally Posted by
elcruxio
While that might be true the end result could end up being pretty darn bad in general. Steel rims are difficult to manufacture to the complex shapes aluminum rims are extruded to and the resulting rims would likely be less stiff than aluminum rims in all directions especially if one tried to get close to aluminum rim weights. Also I'm not sure steel rim walls would manage without flexing in such a system.
I didn’t say it was a good idea. I only said from a braking stand point, you could use a pad that would be more effective than rubber.
As to making the rims, there are all kinds of complex shapes extruded from steel. It would be trivial to make a steel rim in exactly the same shapes are aluminum rims. You mistaken about the properties of steel. Steel isn’t a flexible material. It’s 3 times stiffer than aluminum. Steel rims have been made in the past and a steel rim is the opposite of flexible. A steel rim doesn’t need the same shapes as aluminum because it is inherently stiffer. It wouldn’t need to be double walled to resist bending. A steel rim at the same weight at an aluminum one would be stiffer and stronger.
I’m not advocating steel rims, however. This is just a thought experiment.
Originally Posted by
elcruxio
No it's not. Rotor truing is far easier and far less stressful than truing a properly tensioned and properly sealed wheel (sealed as in first lubricated and then thread locked with either a certain type of oil or with actual thread locker). Truing a wobble wheel is even more difficult if it hasn't been lubricated in the first place. Just had the pleasure of truing the machine built wheels of my new bike and it was horrible I tell you.
I’ve been building wheels for 30 years. I’ve never heard a spoke and nipple being referred to as “sealed”. You have the process reversed. A thread preparation is applied to the spoke before it is threaded into the nipple. The spoke/nipple junction is then lubricated with an oil of some kind. The thread prep is used to keep the nipple from vibrating loose by putting material in the threads but it doesn’t “lock” the threads. The spoke/nipple junction is never “sealed”. In fact, during truing, it’s advantageous to add some oil to the spoke/nipple junction to make it easier to move the nipple on the spoke.
As to truing a wheel, all that is usually needed is a simple turn of a spoke or two to bring the rim into alignment. There are 22 threads per cm on a spoke. It’s very precise because you have a gauge telling you how much to bend the rim. I teach people how to do it all the time and it’s easy for them to grasp the fundamentals and apply them.
Contrast that with a rotor alignment. The only way to true a rotor is to bend it. It’s only a guess as to how much the rotor needs to be bent. There’s no real way to tell if the rotor has been bent enough or too far. There no small adjustment ability like there is on a spoke. I’d much rather make adjustments to something by using threads than by simple bending it.
Originally Posted by
elcruxio
Probably depends on the brake. With modern calipers you need to set them up with a significant gap or the brake won't work as intended. With mini vees and road levers you need a tiny gap and you'll be adjusting it constantly. With cantilevers again you need a tiny gap to get any kind of power out and even then it's pretty abysmal what you can get. With actual vee brakes and mountain levers a decent gap is again ok. Just before midway is the best place for the brake to actually bite I find.
You are saying to opposite things. Do you need a significant gap or a tiny gap? You’ve said both. People set up rim brakes with a significant gap but there is nothing that says there has to be a significant gap. It doesn’t improve the performance of the brake. Even if there is a smaller gap, there is nothing that dictates constant adjustment.
Originally Posted by
elcruxio
My BB7's bite at half pull and I get pretty nice performance from them. I've tried the instant bite too and didn't care for it as it A) makes the bike noisy (now I did say truing rotors is easier than truing wheels but I don't actually bother truing rotors all that often) and B) means I need to then adjust the lever travel as well and that's a hassle. I mean I could do it, but I'm not really sure where the adjuster screw is in my brifters if they even have one... In terms of when a mechanical disc brake bites there's no reason why you'd get any less power with a later bite point if the brake is otherwise setup properly. The most important factor of course is that with a single moving pad system the immobile pad is as close to the rotor as possible. With dual moving pads.. I dunno, I had such a bad time with the Spyre that I've temporarily given up with that.
I think most levers these days even compensate for travel so that's not a reason either.
You keep saying things that make no sense. There is no lever that compensates for caliper travel that I know of. Brake levers are simple mechanisms. The lever is a body that has a pivot point on it and a lever that rotates around the pivot. What would compensate in that system from caliper travel.
Disc calipers and rim calipers work on exactly the same principle and very, very similar mechanisms. Something moves the pads into the rotating metal disc. Whether that is an arm or a piston doesn’t really matter all that much.