[robertsig]

I grew up in the 70's when the UJM reigned king, and I've always loved that design. To me it's normal - nowadays it's retro.

I've only recently got into motorcycles and I wonder what happened when I was asleep. For many modern bikes, why are so many tails swept up high, seemingly allowing for 12" of space between the license place and tire? What's the purpose of this design, especially on sport bikes?

 

[3crows]

I grew up in the 70's when the UJM reigned king, and I've always loved that design. To me it's normal - nowadays it's retro.

I've only recently got into motorcycles and I wonder what happened when I was asleep. For many modern bikes, why are so many tails swept up high, seemingly allowing for 12" of space between the license place and tire? What's the purpose of this design, especially on sport bikes?

That is really simple, the twin shocks of limited travel gave way to a monoshock with significantly greater travel. The greater travel means the wheels sweep a larger arc and thus need more clearance to the fender. Sport machines use the greater travel to significant advantage. The rear wheel on my 675R will nearly touch the inner fender liner when full compressed. And, it can move downward an equal amount. Static, the wheels are essentially at midpoint travel.



I remember in the day when I thought a machine capable of 100 MPH to be fast, pretty sure my 675R will touch 150 MPH or close. Yeah, things have changed.

 

[Unkle Krusty]

Most of the new sport bikes are pretty ugly. And the seats are too high. No way to attach any bags or top box. However, I can and have done all that on my 006 SV1000S Suzuki. The last of the not so bad looking bikes. And it will do 150.

UK

 

[Offcenter]

That is really simple, the twin shocks of limited travel gave way to a monoshock with significantly greater travel. The greater travel means the wheels sweep a larger arc and thus need more clearance to the fender. Sport machines use the greater travel to significant advantage. The rear wheel on my 675R will nearly touch the inner fender liner when full compressed..

What the heck kind of roads do you ride on that you need that much suspension
travel??
I agree with the original poster. Those sport bikes look ridiculous with all that space
and the passenger perched up high on the rear like she's sitting on a tiny bar stool.
Also the mufflers raised up as high as possible. Why?? They are not dirt bikes.
The mufflers just have to clear the road. Everything I know about bikes
says that they handle better by getting the weight as low as possible and as
close to the centerline of the bike as possible.

 

[3crows]

What the heck kind of roads do you ride on that you need that much suspension
travel??
I agree with the original poster. Those sport bikes look ridiculous with all that space
and the passenger perched up high on the rear like she's sitting on a tiny bar stool.
Also the mufflers raised up as high as possible. Why?? They are not dirt bikes.
The mufflers just have to clear the road. Everything I know about bikes
says that they handle better by getting the weight as low as possible and as
close to the centerline of the bike as possible.

I am not going to argue with you. The suspension travel is there and it gets used. Sport bikes do have high center of gravity and high peg clearance and consequently high saddles. Maybe you do not know as much as you think about sport bikes and super sports. Some of us think those low slung cruiser motorcycles that can barely corner without scrapping pegs are ugly as sin and are at least as driven by the wanna be tough guy Harley look styling as sport bikes are by the boy racer look. Each to their own. The OP asked why, as a many decade sport bike owner going back to the early 70s, I explained why. I saw the evolution of modern bikes and while there is much driven by style and aesthetics if you want to take on a 600 super sport or a liter sport bike on a twisting and winding road on your cruiser, not a straight interstate, you will see exactly how that suspension is used as they disappear into the horizon effortlessly. And some of us do track days and may have racing backgrounds and know how to use them to great effectiveness and the huge suspension travel rides nice, thank you.

 

[SemiFast]

Another reason for the tail up high. Aerodynamics.

Or a better explanation is that there is a void that creates a vacuum behind the rider/bike. Anything you can do to help fill that void decreases drag.
It's the reason roadrace leathers have a 'hump' on back up near the neck. When the rider is tucked in that hump helps to fill the void behind the helmet, decreasing drag.

The muffler has to be up high enough to keep it off the pavement when cornering. It doesn't have to be up swept but it would look dumb if it wasn't.