Has anyone seen it done? I'm thinking that one was enough on the street for my Duck and it was around the same weight. Losing one caliper and disk would be almost as good as expensive wheels. Would need a new brake line and I expect that a master cylinder replacement of proper bore would be required, though not sure on that.
Single disk on front?
24 posts · Started by Willh · 21 Oct 2011
Post 2 by Colonel_Klinck,
#2Hmm I've had to rely on my front disks to stop me smashing myself and bike to pieces twice in the last month. Once was to get me from 100 to 40mph in a very short space when some stupid bitch pulled out onto a dual carriageway (was actually 3 lanes) and went straight from inside lane to outside, as she wanted to turn right a mile down the road. She didn't look and I ended up doing my best rolling stoppie ever. Rear felt like it was a good 18 inches off the deck. If I had only one disk and calliper I somehow doubt the situation would have turned out so well. I'll stick with 2 disks thanks.
Post 3 by Willh,
#3Similar thing happened to me years back on the Duc, longest, highest, rolling stoppie I ever did, and this is why I`m thinking that if one Goldline was good enough to do it then on a 375lb bike than the SD should be able to go with only one radial caliper as well after losing a bit of weight.
Have the wheels off giving them a clean and can`t get over the weight of the calipers. Seems like overkill, although a good place to have overkill, but overkill non the less.
Have the wheels off giving them a clean and can`t get over the weight of the calipers. Seems like overkill, although a good place to have overkill, but overkill non the less.
Post 4 by Ducati Pete,
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Post 5 by Jermo,
#5To be more serious about this:
2 discs can have more stopping power then one.
I believe the main reasons of fitting 2 is looks but most of all heat dispension.
If you brake hard and frequent you need the extra surface to dispose the heat and keep the brake fluid from boiling, discs from fading and maybe even warping.
This is the same reason racing discs are normally thicker (5mm) compared to most stock discs (4 or 4,5mm).
It also balances the front wheel, single sided discs tend to be a little less stable in high speed corners and could give a different feel on lefts compared to rights since the place of rotating mass is higher in one corner side compared to the other side.
I think this last point isn't noticed by most riders though and the heat reason will be barely to not noticed on most street rides.
2 discs can have more stopping power then one.
I believe the main reasons of fitting 2 is looks but most of all heat dispension.
If you brake hard and frequent you need the extra surface to dispose the heat and keep the brake fluid from boiling, discs from fading and maybe even warping.
This is the same reason racing discs are normally thicker (5mm) compared to most stock discs (4 or 4,5mm).
It also balances the front wheel, single sided discs tend to be a little less stable in high speed corners and could give a different feel on lefts compared to rights since the place of rotating mass is higher in one corner side compared to the other side.
I think this last point isn't noticed by most riders though and the heat reason will be barely to not noticed on most street rides.
Post 6 by bic_bicknell,
#6Having twin discs provides TWICE the stopping power of a single disc. This performance gain is offset, (in the big scheme of things), by the weight of the disc and calipers compromising the suspension.
In my humble opinion, the engineers at KTM, (and Moto GP and all the other genius engineers over the years working on bike design), have worked out that twin discs are a better compromise between the, (undoubtable need for weight and cost reduction), and the requirement to stop Colonel Klink smearing himself into the back of a dozy car driver when he needs to stop in a hurry. When appraising a lot of smaller, lighter bikes this equation works out in favour of one disc.
For your relatively heavy, very fast Superduke if you want to take your other disc and caliper and hoses off please do........ but go out and please take care of yourself. And ride slowly.
In my humble opinion, the engineers at KTM, (and Moto GP and all the other genius engineers over the years working on bike design), have worked out that twin discs are a better compromise between the, (undoubtable need for weight and cost reduction), and the requirement to stop Colonel Klink smearing himself into the back of a dozy car driver when he needs to stop in a hurry. When appraising a lot of smaller, lighter bikes this equation works out in favour of one disc.
For your relatively heavy, very fast Superduke if you want to take your other disc and caliper and hoses off please do........ but go out and please take care of yourself. And ride slowly.
Post 7 by Willh,
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Post 8 by Willh,
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Post 9 by Jermo,
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Post 10 by Willh,
#10Boiled brakes are no fun. It has happened to me on my dirt bikes, more than once. Usually old fluid that has taken on moisture. The fulid vaporises and you have no brakes. Try that in the coastal range of Oregon. One thing not to skimp on is the power of brakes. If you are not taking your bike to the track.........do you really need the extra weight loss? To comprise your stopping ability? Ride more, wrench less, bench race less.
Post 11 by Stratkat,
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Post 12 by Stratkat,
#12dude dont be stupid, learn to adapt to them. ive had at least 2 situations where ive had to stop so hard my back wheel has been off the ground, and i wouldnt want to think where id have been if id only had one disc.
find another way to cut weight. you should be thankful we have this technology at our fingertips, literally!!!
find another way to cut weight. you should be thankful we have this technology at our fingertips, literally!!!
Post 13 by Willh,
#13Jermo, did you draw your avatar? very nice!
Post 14 by lcjohnny,
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Post 15 by Stratkat,
#15I think Willh is right this not a simple "2 discs are twice as powerful" point.
A disc does not give a single and un-altering amount of deceleration
For a start any braking system just cannot stop you harder than the tyre to road friction will allow so that is your limiting point.
also the weight loss will be unsprung weight and therefore very useful
2 points tho'
1) twin discs transfer rotary loading to the front forks equally minimising fork twist and aiding steering under braking (although not nearly as good as leading links or Hossak/BMW systems) - think you will need a fork brace?
2) the leverage applied is the ratio of the master cylinder cross-sectional area over the sum of all slave cylinders cross sectional area. So to preserve feel for a single disc set up you will need a master cylinder that is 1/2 the area or about 5/7 the diameter of the twin disc master cylinder.
Like to know how it goes
Jon G
A disc does not give a single and un-altering amount of deceleration
For a start any braking system just cannot stop you harder than the tyre to road friction will allow so that is your limiting point.
also the weight loss will be unsprung weight and therefore very useful
2 points tho'
1) twin discs transfer rotary loading to the front forks equally minimising fork twist and aiding steering under braking (although not nearly as good as leading links or Hossak/BMW systems) - think you will need a fork brace?
2) the leverage applied is the ratio of the master cylinder cross-sectional area over the sum of all slave cylinders cross sectional area. So to preserve feel for a single disc set up you will need a master cylinder that is 1/2 the area or about 5/7 the diameter of the twin disc master cylinder.
Like to know how it goes
Jon G
Post 16 by jambox,
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Post 17 by Willh,
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Post 18 by Willh,
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Post 19 by Willh,
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Post 20 by lcjohnny,
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Post 21 by Willh,
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Post 22 by Stratkat,
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Post 23 by Willh,
#23The rear brake is designed to be weak. The front does the stopping for 98% of the SD riders. Too much rear brake in spirted rides can lock the rear wheel and cause a high side in short order. Back in my real hooglin sport bike days I was taught by my buds to hook my brake foot under the the rear brake pedel so I would not use it. Hard habit to brake with years of dirt bike history. I believe the 690 uses a single front disk, cause they are lighter. You might find a master cylinder off one to try. It's your bike, do what ya want, it's just we hate to see people get hurt or lead others down the narrow path.
There is a bike hanging from the rafters in a local bike shop. It's from the flat track days. It has holes drill in all the tubes about every 1 1/2 inch and are about 1/2 diameter holes. Some people
There is a bike hanging from the rafters in a local bike shop. It's from the flat track days. It has holes drill in all the tubes about every 1 1/2 inch and are about 1/2 diameter holes. Some people
Post 24 by Willh,
#24Crazy fooker only has one disk...
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