Belt Drive Superbike

With all the maintenance that is required of a chain compared to a belt, why are we using chains on state of the art bikes?  Would it be possible to retrofit a bike with new "sprockets" that will allow the final drive to be belt?

Could it just be that belts are more prone to slip compared to chains on high powered bikes?

Cheers guys, sorry if I'm being a noob

Retrofit, while possible technically, is probably not a particularly good idea. You will need to allow extra width for the wider belt to run, which means that you'll need wider guards, and if the current chain runs through the swingarm as it does on some Aprilia's, you're going to need to reroute it altogether.

Now both chains and belts have advantages and disadvantages. Chains are good for high load and off road applications. The gearing can be altered very easily making them well suited to sportsbikes. They are narrow and very strong. They are also easier to repair than belts (or shafts for that matter) and can be made in a variety of colours. Belts are quieter and smoother running. They are lighter than chains and require much less frequent adjustment. However they can, and do, break if the system gets contaminated so have to be kept as clean as possible. You'll not have lube all over your back wheel if you have one fitted though.

Personally I think you'd be better off either buying a bike with belt drive already fitted or just enjoying the one you've got.

98% of the time I'm right. Why worry about the other 3%.

Cheers mate

It was just a curiosity that I needed to sort out.

Thanks a lot!

One of the biggest issues - that no-one's mentioned - is the need for accurate belt tension. You can't run them with "slack" like you do with a chain, so the gearbox pulley ideally needs to be co-axial with the swing-arm pivot, which inevitably gives packaging / chassis problems. As an alternative you need a tensioning idler pulley. It can all be done, but chains are generally a better compromise at the moment.

sexdrugs'n'rockingmole wrote (see)

Why not go for friction drive - where a roller is pressed hard onto the rear tyre and provides the drive and breaking? Perhaps no so bright in the wet though?

bim wrote (see)

Not sure what that does to the rear tyre , i would imagine it would overheat somewhat.

It's a very poor system in terms of efficiency. Losses as high as 95% are not uncommon.

Also, imagine putting 100+ bhp through the sidewall of your tyre. It would need a terrific amount of friction to prevent slippage which would mean massive reinforcement of the sidewall. Of course your suspension would need to be reworked so that it could cope with the superstiff sidewall and it would still be like riding on concrete tyres. As for wear and tear. Imagine changing tyres after every hald decent ride.

98% of the time I'm right. Why worry about the other 3%.

Arranbru wrote (see)

so what about putting a shaft drive into a high powered bike. Would the angular strain put onto the shaft by the engine be too great for the materials we use today. I understand the weight aspect and the unsprung mass would greatly affect the handling but surely carbon fibre or titanium could help this?

Most modern bike development - ie sportsbikes from which the majority of others come - is done on/for the racetrack which requires very easy gearing changes. These can be done very simply with the chain and sprockets set up but are very difficult with shaft drive. Then there's the weight penalty - however small - in unsprung mass which would have a detrimental effect on the handling. Torque steer is obviously another issue.

But most important of all is fashion. Riders see shaft drive as something tourers and BMW's have. It would be hugely unpopular amongst the sportsbike brigade. Even BMW use a chain on the S1000R (amongst others).

Shafts could easily handle the power. Cars use them after all and some of them produce far more than the most powerful production bike out there (190+bhp ZZR1400).

There are a few pros to having shaft drive not least of which is maintenance. Imagine not having to lube and adjust your chain every couple of rides. Or replace it every few thousand miles. Or fiddle about fitting an automatic lube system.

98% of the time I'm right. Why worry about the other 3%.

Sparkwood wrote (see)

My son has a BMW F800S that's got belt drive and BMW told him they have never seen a worn out one although it's changed at the major service at 24K miles, the bike goes extremely well and does'nt hang about for a twin, the ride is very smooth too.

98% of the time I'm right. Why worry about the other 3%.