The harley-Davidson motorcycles are all belt-driven now. Chains are noisy and wear out. I wonder why bicycles haven’t switched from chains as well? A belt is smoother and cheap to replace. Are there such bicycles now?
There are some. A quick google search shows Trek Bicycle and Carbon Belt Systems both producing belt drive bicycles in the first couple of hits. There seems to be quite a few others as well.
A WAG is that most bicycle today change gears by using a derailleur system to actually change the chain from one sprocket to a bigger or smaller one. I assume that a belt with such a system could not be kept tight enough to avoid slippage.
Here are two, one is a single speed, the other has an internally geared hub, so no derailleurs required.
Just to complete the parallels, there are shaft-drive bicycles as well:
I think the inherent problem is that a properly installed chain will transfer about 98% of the force expended from the crank to the rear gear. AFAIK, no other drive system that can compare in weight has proven to be as efficient.
Of course, we are talking about best case scenario with expert maintenance. But, as with all sports, its the top pros that dictate what the posers will buy. (Look at golf and skiing, for instance.)
So, while a slightly less efficient drive system that is far superior on the maintenance side may seem logical, you have to get the people that aren’t top pros to buy it. There’s your dilemma.
Belt-drive city bikes are not unusual in Japan. They are favored because belts do not require lubrication. No need to worry about grease on pant legs.
Belt-drive bicycles use toothed belts, like timing belts on cars. So slippage isn’t a problem. But you’re right that a belt won’t work with a derailleur, which is one reason it’s uncommon on a bicycle. Belt drive bicycles all internal gear hubs or no gears at all.
Another problem with belts is that they can’t be cut and spliced easily. On a conventional bicycle frame (“diamond frame”), the chain goes through the rear triangle of the frame. It’s easy to thread a chain through the frame and then connect it; it’s not so easy with a belt. It’s possible to design a frame that doesn’t require this, but it adds some complexity. If you look at the Trek belt-drive bikes linked above, you’ll see there is a gap in the frame near the rear hub - and a complicated structure to bridge this gap.
Also, because belts can’t be cut and spliced easily, bike shops have to stock belts in several different sizes. A standard length chain can be cut to fit any bike. (Well, unless you have a recumbent or tandem bike, but even then, you can connect several standard-length chains to fit it.)
Chains are really rather easy to keep in good condition. Keep 'em clean, lubricate correctly and replace when they begin to get worn. None of this is rocket science nor very expensive. It doesn’t require highly trained mechanics or sophisticated tools either.
What’s up with those internally-geared bikes? Is gear switching a lot quicker and smoother than with a derailler?
You are right but also wrong. Some people can’t be bothered to even oil a chain. I’ve been on long group rides for charities where riders show up on bikes that are so neglected that they make more noise than a rock band. They would be far better off with a less efficient drive system that needed no maintenance than the chain driven machine that they are squealing away with.
A pro rider is looking to get every bit of efficiency available. If you are in competition you are not going to trade in a chain that is 98% efficient for a belt that is 95% efficient even if it requires less maintenance. Again, like golf and skiing, the wannabees follow the pros. That’s where the mass market is. Somebody has to pay for the freebies that the pros enjoy. That’s why sports equipment is so expensive and so imitative of the pros equipment.
FWIW, if you have an REI store near you I know I’ve seen belt-drive bikes there, if you wanted to check one out.
It’s different - I own an old Raleigh with a Sturmey-Archer three-speed gear.
Advantages to hub gearing are simplicity if the chainline, allowing the use of chainguards. Also, the gear can be changed while stopped - an advantage for city bikes.
They are less efficient, though, don’t allow quite as much gearing, can be more expensive and don’t shift as well when under load - you have to pause pedaling for a moment.
Ther are some folding bikes that have belts:
from this site:
look at the Microbike, the Strida, and the Bernds.
So true. It’s just like all those posers riding around on speed bikes. Why the hell are they on those uncomfortable things? To make it easier to ride and finish the course quicker? Why would you want to do that, you’re trying to excercise! And those ugly bike clothes. Ahhh
I can’t tell if this is sarcastic or not. Spartydog is a dumbass, don’t try to be like him.
I have no idea what a “speed bike” is. Riding faster generally means you go further in the same time. Most of those “posers imitating the pros” actually arent trying to “exercise”, that’s just something that happens while they are out for a bike ride.
I’d love to have a belt drive on my single-speed, all-weather, commuter bike. It has one gear because I want the bike low maintenance and to be ridable in any weather without meticulous cleaning afterwards. As far as my “poser”, “pro-imitating” “speed bike” goes, however, you can’t beat a chain and derailleur.
Oh yeah. It’s also totally uncomfortable, so I can only ride it all day not all night.
Sorry, meant road bikes. The ones with the hooked handlebars for hunching, tiny seat for asshole stimulation, and precariously thin wheels for slipping into oncoming traffic. And spartydog may be a dumbass, but he’s a pro dumbass. That’s why I try to be like him.
Because they are designed to be ridden fast on the road. The people riding them want to ride fast on the road, therefore they have a purpose built road bike.
Someone on a bike generally wants to be visible, so the clothes are bright, it’s not too difficult to understand really.
For a road bike there are no real advantages over a chain - nuances either way but not enough in it to get excited about belts. I’d say they were out of the question for a mountain bike - wouldn’t last 5 minutes in the dirt we have here in the UK - maybe OK in sunny California.
The requirement for an internally geared-hub would also be a big problem. The rohloff has it’s niche, but the overwhelming majority of MTB riders are happy using a derailleur and cassette. Include the dodgy frame bodge scr4 mentioned and belts are a non-starter.
The bottom line is that true innovation on a bicycle is inordinately difficult. So we’re faced with armies of bicycle marketing people trying to dream up new ways of fleecing us riders out of our hard-earned, whilst providing little if any improvement to our bikes.
The motorcycle industry is a good place to get ideas from, though. The R+D budget of just one of Honda, Kawasaki, BMW etc dwarfs the entire bicycle industry.
I’ve got a Strida with the belt drive. As long as you keep the tension on the belt to stop it slipping it’s fine.
Note that the UCI bike federations and such put a lot of restrictions on innovation in bicycles (like no fairings allowed) which in turn prevents a lot of “trickle down” effect you see in other sports. Top racers not using belts doesn’t imply that they aren’t as efficient as chains.