Why the bloody great gap?

[Tony Norton]

Somebody must have the definitive answer. Why is the clearance between the top of the rear tyre and the tail piece of most bikes nearly twice what it needs to be?

I've researched a bit and looked at the half dozen most common bikes of around 650 cc. The makes I looked at were Y, K, S, H, T and B. (You can suss the makes by the initials).

The highest rear wheel travel is BMWs, at 6.7", the average was 5.1". In every case, scaling the measurements of photos using the rear wheel size of 17" and, without exception, the gap calculates at 8" to 9". Way more than is necessary to clear the rear tyre. We're not talking about off-road bikes here.

Is the excessive height of the tail because they want the bike to look faster? (does it?). Or is it so a pillion passenger can look over the head of the rider? Perhaps it's because all the others do it.

I can't think of a logical reason.

Any ideas?
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Newbie in 2021 at 83. Now the proud holder of an A2 licence. That's far enough, or was, until I became ambitious.

[doggone]

There will be a lot less with a fat rider on board and imagine a pillion too.
Otherwise - fashion really.

[MarJay]

Because it looks good? ‘Squatting dog’ bikes look dumb.
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British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[A100man]

It wasn't always this way..

..bikes ine 70s-90s had proper rear muduards too and grab rails - none of this selfie stick nonsense.

Daft fashion that offers no function that I'm aware of.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[Tony Norton]

At the moment my inclination is to agree with A100man.
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Newbie in 2021 at 83. Now the proud holder of an A2 licence. That's far enough, or was, until I became ambitious.

[Tony Norton]

doggone,

I think there's one point you are missing. A stat that is not included in most lists of specifications is the front and rear suspension travel. If you go to: -

https://www.motorcyclespecs.co.za/

you will find that the spec sheet includes front and rear wheel travel. No matter how much weight you put on the back, that is the limit of movement you will get.
A common figure is 5.1" for rear wheel travel.

MarJay.

I guess with 105bhp on tap you can ride around town at 30mph with your heels up your a**e and you chin on the tank, looking like a racer. Dream on, evryone has to have a dream. Enjoy.
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Newbie in 2021 at 83. Now the proud holder of an A2 licence. That's far enough, or was, until I became ambitious.

[jonquirk]

I have a Trident 660. One the reasons my partner likes it is that the elevated pillion gives her a better view past my shoulders. One of the things I dislike about the bike is that there is no space under the seat for storage. Reducing the clearance above the wheel could have created room for a toolkit and somewhere to carry my disc lock, just like my old BMW G310R managed to provide. She doesn’t like the flat seat on my R60/7 because she can’t see past me.
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2021 Triumph Trident660
1978 BMW R60/7

[stinkwheel]

Race development drives design. Race bikes have elevated tail cowls for aerodynamics so there is smooth airflow over the fairing, over the riders crouched back then on off the rear of the bike. People like to ride a bike that looks like a race bike.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Tony Norton]

At last, thanks to stinkwheel.

The influence of racing on street use exists everywhere. ERS in F1 for instance and, going back even further, aerodynamics and its effect on body shape.

On the other side of the pond however, Harley and Indian have realised that some riders like to be comfortable.

Thanks for your input mate.

Tony
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Newbie in 2021 at 83. Now the proud holder of an A2 licence. That's far enough, or was, until I became ambitious.

[Fat Angry Scotsman]

[stinkwheel]

[MarJay]