wrote:
On Saturday, February 2, 2019 at 12:47:07 PM UTC-8, Roger Merriman wrote:
wrote:
On Thursday, January 31, 2019 at 5:07:40 PM UTC-8, Roger Merriman wrote:
wrote:
On Wednesday, January 30, 2019 at 7:27:08 PM UTC-8, James wrote:
On 31/1/19 5:02 am, wrote:
On Tuesday, January 29, 2019 at 2:59:39 PM UTC-8, James wrote:
On 30/1/19 6:13 am, wrote:
On Tuesday, January 29, 2019 at 6:07:16 AM UTC-8, Roger Merriman
wrote:


You’d think it would be so, but really quite differing brakes
don’t seem to cause confusion. I will admit that first time I
use the MTB with is 180mm etc disks they are so instant, but
actually you don’t lock, it’s a very easy system to use to it’s
full, ie tyres at the point of locking but not quite etc.


If you're applying the disk brakes and hit a bump it is WAY too
easy to lock the brakes up.


Disk brakes are normally associated with better brake modulation
than rim brakes. That means with disk brakes you can achieve more
brake effort without locking a wheel. You seem to be contradicting
that.

-- JS

Not really. A full suspension MTB has a different center of gravity
and weighs twice what a road or cross bike does. When you have 2"
wide tires and a great deal of weight disks do modulate much better
because you can retain traction most of the time.

Whether the bike weighs 10 kg or 20 kg does not change much when the
rider weighs 80 - 90kg.

The biggest difference is that a full suspension MTB will retain tyre
contact with the road or track surface better - however, as you start to
brake the suspension forks should compress which starts to rotate you
over the bars, which is bad.

There are two problems with a xcross bike - it weighs very little - a
32 mm cross knobbie can easily have so much traction that the bike
can rotate around it's much high center of gravity. And on hard
surfaces you can lock the brakes very easily since there is less
traction.

Regardless of bike weight, if you're going to brake hard you must move
your body backwards as much as possible, to prevent the rear wheel from
lifting. Even motorcycle riders who do defensive riding courses learn this.

My gravel bike comes standard with 42mm tyres. It can handle slightly
wider. Not dissimilar to many MTB tyres.


With road bikes they reduced the size of the disks dramatically. The
reason that they even went to disks was to not wear out expensive
carbon rims. So instead they wear out easily and cheaply replaceable
metal disks. Using Campy skeleton brakes I can easily lock the brakes
if I wish to. So what would I gain using disks other than cheaper
replacement costs?

Smaller disks on road bikes is because there is significantly less tyre
on the road - but it should still be possible to lock the front brake
and send yourself over the bars, especially if you don't move your body
backwards.


I am not anti-disk brakes but there are horses for courses. If you
are building a superlight bike with superlight components why would
you put an very un-aerodynamic and heavy disk brake systems on it?

3 months of riding my Colnago with carbon wheels show less wear that
a single month on aluminum wheels. Though I have to replace the
basalt brake pads all the time.


It facilitates easier CF rim use, and doesn't require rim brakes to have
a quick release so the brake pads can be moved out of the way of wide
tyres. You know the pros use 27 - 28 mm tyres for cobbled classics?
They won't get past properly adjusted rim brakes without a quick release.

--
JS

I don't think we agree on this: I weigh 84 kg and a 20 kg bike most
assuredly climbs slower than snot on a cold day. With my cross bikes I
would come up behind a FS 29er and try to pace him because I don't like
blowing by people as if I were better than they. But eventually I just
can't go that slow and have to pass. Though I try to do it mildly
until I'm out of sight.

I will say that really rough, steep climbs that you have to carry a cross
bike up these long wheelbase MTB's can carry such a low gear that they
can climb almost anything.

I have 28's on my Time VX Elite with an Ultegra group on it and the brake
releases work fine. Let's remember that today's disk brake bikes have 10
mm one piece axles and so there is no such thing as a quick release. Plus
you have to thread the wheel between the forks plus carefully insert the
disk through the brake pads without knocking them off.

That's why most of the road racing teams are not using disks


Unless they are E-MTB or possibly downhill a full suspension 29er will not
be 20kg, mine which is at best mid pack, is 12/13kg I’d agree that
cross/gravel bikes tend to climb shallower smoother climbs such as fire
roads faster, sometimes by quite a bit equally once it gets steeper and
rougher the MTB will shine.

What race mechanics may not find difficult shouldn’t really be a pressing
problem unless your a race mechanic, if your riding with a support car,
where wheel change speed matters then possibly something to consider.

Roger Meriman

Concerning the wheels I should add that you can't sit on the ground and
play mechanic very easily and you end up standing and somehow trying to
balance the bike without a wheel of finding some spot to lean the bike
while you play mechanic on the wheel. Putting the wheel back in under
these circumstances is clumsy at best.

Why not? Personally generally do just flip the bike over though it’s a
fairly cumbersome object it’s not heavy really so easy enough to just flip
it over should I need to. MTB will not fit but the Gravel bike with wheels
off will fit in the boot of the car, though admittedly I sometimes just
slot the forks on to the wheel, while sitting in the boot, both are easy
enough.

Roger Merriman

I don't know what sort of equipment you have but it would be a cold day
in hell when I balanced my bike upside down on my $80 saddle and my $250 Record levers.


I live in the uk, and ride off road mostly, while things might get mud,
which they will anyway, soft ground is unlikely to harm the bike, clearly
if one was truely brutal I guess? And equally being off road bikes they
will get war wounds from use.

The bikes shouldn’t be inside down is one of the many old wives tails.

Roger Meriman