V-brake vs hydraulic disk-brake - which is more environmentally friendly

Question

Let me start the question by saying that I have a pretty good impression of the advantages of disk brakes vs. V-brakes, so I'm not asking about performance comparisons.

I'm MTB-ing several thousand kilometers per year, and most of those are on the mountainside, where I have nice climbings, but also nice downhills (honestly I don't know which I like best). The thing is that I currently have a V-brake equipped bicycle, however for performance/safety reasons I'm strongly considering moving to hydraulic disk brakes.

But, on the other side, I also try to be as environmentally friendly as possible, this is why I rarely change the consumables of my bike, even if overly-used ones make it difficult to ride smoothly.

Before I switch to hydraulic disk brakes (I'm not currently taking into consideration the cable disc ones), I'd like to find out if they are more environmentally friendly than the V-brakes, or not.

V-brakes:

• use some kind of hard rubber/plastic, not sure how degradable are the molecules that get ripped while braking
• they also wear out rims, from my experience I need to change them after 10.000km
• the cables don't degrade that easily (at least compared to the shifter ones), I currently use ones bought 20 years ago and they are still in 100% shape
• the cable housings also don't need to be changed often, I usually oil them and gain one more year of easy braking

Disk-brakes:

• need an extra disk, which poses an initial environment impact
• the mineral oil should not have an environmental impact, right, as it's mineral
• the brake pads wear out after a while, I assume they are made of metal, so they should have a less environmental impact than the rubber/plastic from V-brakes
• the disk also wears out after a while, however, that's still metal, which should be recyclable
• zero impact on the rims!!!

Is my evaluation correct? Did I miss something?

Answer 1

We can assume that V-brake pads are essentially non-degradable. The same is true for resin disc pads. But are non-recyclable. Metal disc pads seem to be various copper alloys which are probably OK in the environment in such tiny quantities, especially as they'll oxidise, and should be recyclable as scrap metal. There are also ceramic pads form which the dust should be comparable to stone dust - I won;t use them again after they contributed to a bad experience; they also increase rotor wear.

Rims shed aluminium, and discs shed steel, both in tiny quantities; these are probably equivalent.

Rotors last quite a long time and are recyclable. Cable inners are similarly recyclable, outers less so (the plastic coating probably ends up burnt if you treat the housings as scrap metal).

You say the mineral oil should not have an environmental impact, right, as it's mineral but that isn't true. Spilt oil is quite polluting at the surface. You shouldn't ever spill any in the wilds, but if you change your oil it will probably end up in landfill, soaked into rags or in a small container; that's also true from bleeding though in smaller quantities. Some disc brakes use DOT fluid - don't swap or mix brakes fluids as they're not compatible. DOT fluid is based on polyglycol ether and is also something you wouldn't want to release into nature.

So on pad materials, metal pads on disc brakes win, but on pollution potential and disposal of other consumables, cable brakes probably win. I say cable brakes there, and not V brakes, because cable discs are probably the best all-round option for you. I run BB5s on one of my bikes (a tourer that I treat as a gravel bike), and seriously considered those or some other cable discs for my MTB*. If you're happy to run V brakes, cable discs will be at least as good, slightly better in the wet, except for the very worst ones. My comparison is with a hybrid that again I take off-road, with V-brakes and the best pads I can find.

So cable discs, that you dismissed, would work out best overall (with metal or ceramic pads).

Aside from local pollution, manufacture and shipping have an impact from energy and materials use. To a first approximation you can consider the lifetime mass used up, but note that manufacturing aluminium is far more energy intense than steel, so rotors would beat rims.

*_{in the end I went for an upgrade to the poor quality hydraulics it came with.}

Answer 2

The world is full of perfectly good cantis, v-brakes, and rim brake wheels that sit unused since disc has taken over. Using what we've already produced for its actual full service life is pretty hard to beat for environmental impact in this and many other cases. Making metal things has a large environmental impact.

Consider also that you could procure some hydros that are being trashed or sitting unused because there's something wrong with them that's not considered monetarily viable to fix, like needing a seal overhaul with parts that aren't readily available, but you might be able to do some make-2-good-ones-from-4-bad-ones tricks on.

If you were comparing in a vacuum, i.e. you had to buy either system new, you cannot divorce that question from your projection of how many rims you think you're going to go through over the life of either system. From there you need to think about what your habits are in terms of wearing through rims from braking if you use rim brakes. But, one of the major considerations is also even if you go to discs, whether your rims will die by violence before the wear-saving effect of disc brakes would amount to anything anyway. For many mountain bikers the answer is yes and the rim wear point is basically moot, but maybe not if you're a casual rider (unlikely to damage a rim by impact) and/or heavy braker and/or ride in conditions that are particularly hard on rims used with rim brakes.

Answer 3

The true answer is: It really doesn't matter. You are riding a bicycle, that is what matters. If you are truly eager to minimize your ecological footprint, caring about the break type on your bike is wasting precious resources better employed elsewhere.

As an example, if you are concerned about micro plastic coming off brake pads: Stop wearing the "functional" synthetic bike clothes which release orders of magnitude more micro plastic into the environment with each wash cycle. And so on. Of course you are probably already wearing Merino, but that was only an example: Almost every even very innocent-looking aspect of your life will have an orders of magnitude larger ecological impact than your bicycle brakes.

Answer 4

V-brakes with good pads are probably better from environmental standpoint due to the slow wear rates of pads and rims compared to the wear rates of disc pads and disc rotors. Besides, disc brakes often use resin pads and I don't believe the resin is any better than rubber for the environment when worn away. Anyway, your tire wear rate far exceeds your brake pad wear rate, so in any case, if you're worried about brake pad rubber you should be worried about tire rubber.

Good V brake pads (such Kool Stop Salmon) last easily over 10 000 km in dry conditions. Rims probably last several times that, 50 000 km - 100 000 km in dry conditions. When wet, both pad and rim lifetime suffers but in varying conditions I would be very surprised if a good pad leads to shorter rim life than 20 000 km. Of course if your "varying" means mountain downhill in rain only, then you can wear rims in as little as 2000 km.

Resin pads in disc brakes in dry conditions last 2000 km, about tenth of that of good V brake pads. Discs last about six pads, or 12000 km, less than rims, but they are somewhat lighterweight too (about third of rim weight). In wet conditions these are probably not as severely reduced as with V brakes. Metal pads could improve pad lifetime at the cost of disc lifetime, not sure if this is a good or bad tradeoff.

I suspect if you have been getting 10 000 km rim lifetime that you are riding in varying conditions including wet, and you are not using Kool Stop Salmon pads. It's time to switch your pad brand! Good pads make a lot of difference especially when wet. The Salmon color is due to iron oxide in the compound, and without that color you can't have good pads.

Also as you correctly noted, mineral oil has an environmental impact too.

On the other hand, which is better for whoever pays for bike maintenance, the answer is disc brakes since rim replacement has high labor costs.

Also for the rider in the wet disc brakes are far better because of the consistent performance and no lag.

Answer 5

Safe way of riding has the most of the ecological impact. If you hit even not a human, or just have near pass somebody has seen, this promotes the view that bicycles are not safe enough for practical use. This may prevent somebody from switching into this way of transportation.

Due that I think it is better to use say lights in the night, even if they have ecological impact. If I ram into something in the midnight with no lights, somebody will say "what an idiots these cyclists are". This discourages others from using bicycle for commuting.

For the same reason, I think, disk brakes are more environmentally friendly, as they give more control on the bicycle, this way reduces the number of accidents, this way increases the popularity of cycling. I have disk brakes on one bicycle and rim brakes on another and when I switch the bicycles I clearly see the difference. This way no brakes at all (I mean, a fixie) will do more ecological damage if you get into accident preventable by having a brake.

If you can maintain the rim brakes so that they are equally efficient, this answer does not apply to you.

Answer 6

The differences depend so much on actual conditions that the far bigger contribution to environment friendliness is riding bike at all. So don't care about consumables on a bicycle. They are neglectable compared to any other means of transport.

Use a bicycle whenever possible - that's it.

Answer 7

As a very rough estimate of the environment impact of anything, you can just use its price (including delivery for personal-use products and services).

I am chemist, I know what I am talking about.

Of course, some goods and services are engineered to lower their environmental impact that makes them more expensive, but the general case boils down to your spending.

If V-brakes are good for X kilometers and cost $xx and disk-brakes are good for Y km and cost $yy, you just divide $xx/X and $yy/Y and compare.

Answer 8

This choice would make you feel like you did something, and that feels good.

Not riding would make you feel bad. It isn't an option because you like riding, and you can justify the use by pretending you made a environmentally friendly choice.

Thanks hero!

Answer 9

First, brake fluid isn't mineral oil. You may use mineral oil in your lines but brake fluid is glycol based.

Second, you're only considering environmental impact at point of use. You're not taking into consideration production and transportation impact of your purchase.

Third, much like only considering environmental impact at point of use, you aren't considering the impact of your MTB activities. First, you're using the bike for recreation, not commuting. You're likely driving a vehicle unnecessarily to the location at which you like to MTB. Then, you're destroying habitat with your chosen recreational activity. You think those MTB trails are natural? You think they don't impact wildlife? That's not environmentally friendly. Third, your recreational activity required the production of a bicycle which created significant carbon emissions and excessive use of plastics, along with the safety gear you use.

In summation, your desire to help the environment by choosing more environmentally friendly brake pads is more than offset by your choice to partake in a destructive leisure activity.