why disc brake on rear wheel?

Because under hard braking the weight transfers to the front wheel, the rear wheel becomes so light that very little braking is required to lock that wheel.

Most modern motorbikes DO have a rear wheel disc brake, usually only one disc though because, as Del says, its not needed so much.

John.

My 20 year old Moto Guzzi has 2 disk brakes in the front and 1 disk brake in the rear.

Perhaps they do not allow rear disk brakes where you live!

Even bicycles can have disc brakes (hydraulic even) front and rear. Mopeds and motor scooters often have a rear drum brake, in the interests of slightly lower cost. The same is true in the least expensive cars.

I think this person is talking about antiquated models that are kept being produced at near zero costs such as the indian enfield.

Cost is therefore the only reason as discs are slimline, less weight and better performance per force put on them. Probably the redesign of the rear wheel setup would be out of their budget for now and as there is almost no export market for it, they decide to leave it as it is.

Same with all those chinese little motorbikes.

I think that you might have hit the nail squarely on the head, but as he was only logged on as a guest, we may never know.

Guest, if you are still looking at this blog, please remember that disc brakes are simpler to build and maintain and very efficient. You can see at a glance if new pads are needed and I do believe that they are more progressive/controllable than drum brakes.....that is my impression anyway....especially if regular (rustable) steel, stainless I have heard looks good, but water can be a problem.

My last vehicle with all round drums was a 1963 Hillman Imp I bought in 1964......or 5?

My last car with rear drums was a 1983 (or so) Mitsubishi Galant Diesel!!

Only my caravan (1991) has still got (4) drum brakes, but these are well designed and easy to adjust, not like some others I could mention!!

Double linked drums are very good infact, if you have the latest ones used in racing just before they went out of fashion, you would have a job to find normal commercial discs that work any better.

The only drawback on those is that engineering knowledge has to be exeptional before you can replace, reset and adjust them properly as they are much more complicated than most will have you believe.

Therefore they did go out of fshion and now we have simple, efficient and good looking discs. Have you seen the ones that combine drive sprocket with disc all in one? Very neat.

Yes, they are very neat indeed.

Double linked drums are very good infact, if you have the latest ones used in racing just before they went out of fashion, you would have a job to find normal commercial discs that work any better.

I built a 250cc single gp roadracer in the 70's and used a double leading shoe brake from a Triumph Trident. Because it was intended to stop a bike more than twice as heavy, I machined every surface to lighten it, and in the process machined in some cooling fins. Also put lightening holes in the "cone". Looked quite cool. Fun project, and it stopped remarkably well even under the abuse of racing.

My '93 Ford Mondeo still has rear drums.

Thats what you get for driving a Ford.....!!!

But I do believe that some other makes were no better......

My Volvo 245 of 1980 vintage had disks front and back and a little drum, in the rear disks for the handbrake......

Fiats of the late 70s had disks all round and an ingenious handbrake system (looked terrible but it worked) to push the pads onto the disk of the rear wheels for parking!!

Disk breaks for rear wheel are there in mobikes specially in powerfull racing bikes

My 27 year old Honda GL1100 has disks on front and back. Two on front and one on the back, can lock up both front and rear wheels if you put too much power on the lever or peddle. Last bike I had with drum brakes was a 1957 Harley Davidson.

You said it perfectly to my mind, drums went out by the mid 1970s i feel......

their discs don't work much better trust me. I have got several.

Not quite clear what you meant, sorry. But as far as I am aware, almost any Bike sold in Europe today has disks front and rear.....

a little off topic, but why don't bikes have one lever that applies both front and rear brakes similar to a car?

If you apply hard breaking in the rain to the rear you will not loose control. Just slide a little, while hard braking to the front can cause the bike to make a sudden movement to the ground horizontally, similar to blowing out a front tire. Both of which can make your day a very bad day. So to answer the question, Differential breaking is necessary when driving the motorcycle in various weather conditions. In the winter I use only back brakes whenever there is a chance the roads are patchy ice.

Although I tend to agree generally with you, I see a fine point of difference with particular regard to the way you brake in winter. It may be difficult for me to put down exactly what I mean as proper braking of a motorbike is more a feeling than a fact....I will do my best....

In non icy conditions, I always brake with both brakes, using the front brake a tick earlier than the rear, ALWAYS feeling with the seat of my pants as to how the bike is reacting as even gravel or sand can cause problems.....similar to ice to my mind....that is how I was taught in the early 60's, keep the bike in balance - front to back.

In winter, I reverse the procedure slightly, using the rear brake a tick earlier, but with the same "butt" feeling as to how the bike is reacting, as we cannot always see far enough ahead and I might be on an icy corner when braking. Using only the back brake will have me off as quickly as with only using the front brake on a corner with or without ice.........

Timing is really critical and I really cannot give hard and fast rules, even after thinking about it for some time!!

The great Saviour of good motor bike riders is the ability of passing your speed to the conditions correctly. Many cannot seem to achieve that which explains why every year, many cyclists are killed through their own stupidity!!!

I apologise for the way I have written this, it does not completely say what I want to say, but I am lost to find the right way to say it.....I hope that it is near enough for Government work as they say....

Bike riding is more feeling and experience than anything else when the conditions are perfect, even more so when they are not.

I have not had the chance to ride a bike with ABS (BMW for example), whether or not this is a good improvement for the rider or not in icy conditions I personally cannot say, but I would anticipate a big YES on that score....perhaps someone could enlighten me who rides an ABS Bike....

See post #1...

If you really want to lock up the back wheel every time it's a fine idea.

I find that once the rear wheel is in the air it tends to lose effective braking...maybe someone can explain this?

Del

Del, you need to have "Air brakes" fitted, exactly the same as aircraft have, then you can stop in mid air much better....

You are not so much driving on the road, more I guess flying low over it!!!!

I was referring to a 'stoppie'

Del

The air brakes will still help you NOT landing on your nose and getting all your fur mussed up!!!

stopping a car is different from two wheeled bike you have to distribute whole cars mass to wheels were car balancing is not matter of concern for exceptions of steep turns , slippery conditions , with bike you have two wheels for balancing and turning , you cannot apply both brakes simultaneously everytime , when you turn you apply pressure more on rear side to front , you do want to stop abruptly you apply more pressure on front to rear , i do utilise both brakes every time when riding a scooter due to weight ratio of 30:70 front to rear

I rode a scooter many years ago and the differences between a scooter and a bike are huge....especially with regards braking, weight changes....I have stepped off a scooter (in flight so to say) as I would rather take my chances without it!

I am not saying that you should never step off a bike, but I have never had the need up to now.....

Yeh..when I lived/worked in London I had a Lambretta...can't beat 'em for city traffic.

Back brake was hardly worth having...instant lock up if used in anger. (Front brake was as aeffective as a spongecake!)

loads of modern bikes now do actually have proportianally linked inteligent braking. Cost some but seems to work ok. Recall a test of the different systems about and the verdict was that even tho there was a distinct difference in performance between the systems, they all worked better than the old fashioned seperate ones.