Two rim brake calipers on front wheel
 

Tempted to try this out. It can be done with a set of aero rim brakes that mount to the fork rear, such as TRP T925. Mount the front one to the rear of the fork and the rear one to the front of the fork.

Anyone ever done this? Would the additional forces damage the fork?

https://cimg5.ibsrv.net/gimg/bikefor...f0ebc20ef7.png
your idea reminded of this.

Ha, tempted to add a coaster brake

Most brakes are effective enough to launch the rider OTB at full effort. And forks generally survive that.
Double brakes will not increase the force on the fork.
Well, maybe a TINY bit, by locking the wheel a tad faster.
I wouldn’t worry about THAT part of the scenario.
Tandem riders sometimes use double brake setups. But usually rim + hub brake combinations.

IMO there's no stress related reason why you shouldn't do this.

However, there may be a simple reason why you couldn't ------- How do you plan to mount two brakes back to back through the one hole?

You mount the caliper going to the rear of the fork onto the longer recessed nut and attach the nut to the front caliper's bolt.

For T925 you have to swap the bolts to do this

One of the really nice features of having only one caliper per lever and having a caliper on each wheel is one can modulate the braking forces and better control their bike is varying conditions. So in my world having two calipers on one wheel would mean that each has its own lever, pretty much eliminating the ability to have the other wheel have its caliper on its own lever and still be able to modulate that brake.

I have thousands of miles on tandems and have the rear hub brake (sometimes called a drag brake) controlled by a bar end "shift lever". Fine for setting an amount of brake application but it rots for any real modulation. Early on my first tandem used a brake lever with both ft and rr calipers controlled by it, two cables entered the lever. With the different cable lengths and different "power" that a ft and rr brake have getting the balance between the two cables was impossible. Oh, one could set up the balance to work OK at slow speeds but than it would be poor at higher speeds.

Are you having stopping problems with the usual single caliper on each wheel? I wonder what problem you are trying to solve. Andy

Correct, one lever for each caliper, both on the front wheel. Should result in more braking power than F + R due to mechanical advantage
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Braking power is always limited by the available traction. Think about that.

My vintage tandem came without the rear drag brake setup so I experimented for a while using two rear calipers with a brake cable splitter/doubler from the lever. I’d have to say that experiment failed. I found I got better braking, and certainly better brake “feel,” from one caliper. I found my experiments with brake shoes more fruitful for improving brake performance. Conversely, I’ve always found it pretty easy to achieve as much brake performance as I need on the front with a single caliper of any kind. So, other than achieving a unique look (which I can’t discount), I think you’ll find two up front aren’t necessary.

You'll need something like this

​​​​​​https://www.thebikesmiths.com/produc...RoCdikQAvD_BwE

Good point, yes I think traction will be the limiting factor here especially with a 23mm in the front

and quite possible loss of control with over braking on the front, speaking as person who has gone over the handle bars with kookstop salmon pads on universal 88 brakes

also you lose the ability to brake and control from the rear brake.

put is this way....do you see any pro's road or mountain using a set up like this? if there were an overall advantage you would

IMHO no value add, along with fussy implementation not advised

Scratch up the brake track with coarse emery cloth and one brake will put you over the bars.

Or (and probably usually for the front brake) the dynamics of stopping and not going over the bars. In the rain is the one place where two calipers in front could be really good as the rear would wipe the rim for the front.

I'm not sure that I've had a bike that had enough brakes to lock (skid) the front wheel on dry pavement, and I'm not sure why that would be a performance goal to chase.

Pretty much all of my bikes, though, have enough brakes to lift the back wheel, at which point 'more' front brake just means that you can launch yourself OTB just that much harder.
One front brake should be sufficient for this, if it's not; you've got your setup wrong

The only time I've seen this done with any "success" was on a bike set up for a rider with one severely deformed hand. That hand was unable to operate a brake lever so his other hand had to do both. It worked in a manner of speaking but certainly wasn't ideal.

Actually front wheel braking isn't usually limited by traction. Instead, what matters is the "tip vs slide" calculation.

Essentially, What matters is the slope of the line from the front wheel's point of contact on the pavement (where braking forces happen) and the center of gravity of the rider and bicycle. For practical purposes consider the braking force to be along that line, and producing both a vertical and horizontal vector. As long as the vertical vector is less than the rider (and bike's,) weight, gravity will keep the bike down. As brake force is increased, that vertical component increases, until eventually it's large enough to lever the rider upward.

Note that this is a cascade phenomenon, because as the rider lifts, the line of action changes in a way more favorable to further tipping unless the brake is released (or eased off). Overall, safe and effective front braking is about skilled modulation and keeping the CofG lower and farther back from the front wheel, which is why it's virtually impossible to have an endo on a recumbent or tandem.

There are two other key factors ------ While, tire traction is usually adequate to achieve a tip condition in most cases, slippery conditions may become a limiting factor. There's also a dynamic factor, which I liken to shifting cargo in trucks, Inexperienced riders in a panic stop often relax their arms such that as the bike slows they slide forward, in such a way to change the vectors in a way favorable to tipping. This may explain endos that it theory shouldn't have happened.

So to the OP - if you can stop hard enough to lift the rear wheel, you've got all the brake thee bike can tolerate. OTOH - if you cannot reach the tipping point, then more brake, wisely moderated, MAY help.

Nope. Unless you have crappy brakes now, you should be able to cause an endo with a single front brake. Shifting your weight to the rear allows you to get braking from the rear brake as well.

When I lent my wife's Trek FX with linear-pull brakes to my daughter's ex-boyfriend, the first thing he did at the bottom of our hill was squeeze a handful of front brake and somersault over the handlebar. We spent the afternoon in urgent care waiting for the doctor to stitch the cut in his chin. So my first question is, what do you want to do this for?

Haha great story

Operationally it looks like it's a no-go. Setup needs a non-standard serrated washer through the recessed nut. There's also the issues mentioned above. Might still be useful for a tourer where faceplanting is less likely

I've only seen dual front brakes on trikes, usually racing trikes, like Longstaffs.