RE: Why are modern bikes so heavy? - 2

That is a very good question. My guesses?
Wheels, tyres & brakes. These things are much bigger. The first Yamaha cast wheels were incredibly heavy. The modern RS wheels are probably lighter, even with the bigger discs. There is no getting away from a "Z" rated 180 rear tyre as being heavier than the stuff fitted to Bonnevilles "back then". 18 inch narrow spoked wheels with half-drum brakes would be lighter. Chain is lighter than shaft too.
Overall size - modern bikes like the RS can take 2 larger sized people. The 60s - 70s models were often much smaller.
Front forks - I can't see how the USD forks on the RS are anything as light as the spindly forks of the period.
Frames - my guess is that modern frames are lighter.
Motor / transmissions - the modern versions are very strong and very reliable. They are also larger. These things will weigh more.
Electrics - today, the electrics are more extensive, but they should actually weigh less - the same with instruments. All modern bikes should be able to run on Lithium Ion batteries; and the tech. dropping cranking voltage draw with automatic valve lifters is pretty impressive.
Seats? Well I can vouch that my Corbin is very heavy, but the std. BMW stuff is lighter than a bike of that time. Bigger, but lighter.
So, I just can't figure it. Ultimately it has to come down to overall size.

I was eyeballing a Panigale a couple of weeks ago and yes, they are quite expensive. But the Ducati SS models are quite light as well and much less expensive. OF course, instead of 214 HP you are only getting 110 but I suspect a 110HP Ducati SS's power/weight ratio is at least equal to our RS which has 10 more HP but nearly 100 more pounds.

Obviously the SS-type bikes do not rate high on the comfort scale, especially at low speeds. I spent years on Ducati sport bikes and I loved them at super-legal speeds or in the twisties but parking lots and low spotted trundling was, at its best, annoying! ;) But I regularly rode them on 300mile day rides with no particular issue at all other than having to wear a backpack to carry anything! :(

My wife, who was at the dealer with me having her Diavel serviced, saw me throwing a leg over the Panigale and also an SS and eyening them wistfully. When we got back home she said, "Why don't you just buy one of those Ducatis? You are always complaining about the weight of the BMW." It's nice to have a wife that's a motorcycle fan/rider!

We're leaving TX tomorrow, heading to the UK where we'll be for 5 months so I'll have some months to think on this. BUT, I suspect that nowadays, as much fun as it might be to have a Duck again, for general riding it's probably no longer a good choice for me.

In looking at all the posts, I think there are two reasons bikes have gotten heavier.
1) We customer always want bigger more powerful motorcycles. The manufactures make their money by giving us what we want. Just look at the R bikes over time. R90, to R100 to R1100 to R1150 to R1200.

The 850 bikes are considered mid size and the F750GS is considers a starter bike. I believe it has more HP and torque that the old R90S. The physical size (especially height) has also grown over time. BMW riders buy big bikes with big gas tanks, it is a macho thing. A bike with only a 200 mile tanks is not a serious bike....300 miles or more is the minimum!!

Technology has added weight and complexity. ABS, oil cooling, water cooling, electrical adjustable suspension, etc etc. All these add weight to some extent.

2) It is cheaper to make a bigger bike heavy than lighter! A Some one noted a Ducati Pengali is lighter, the BMW HP4 is lighter $$$$$

Rumor has it that BMW is working on a new R engine, VVT, who knows what else. Rumored at 150hp or more.

Here is BMW's opportunity to make an industry leading sport touring bike.

My personal dream is thy make a 1000cc version of that engine, make 25% lighter than the 1200 or (1250 likely version). Put in a new bike of our RS decisions but the new bike and 1000cc engine 450 lbs vs our current 520lbs

Guess what we will never see that. Who will buy a $20K 1000cc bike when they can get a 1250cc bike, more HP for the same price!!

We will see a R1250GS (150+hp) and a R1250RT (150+hp) out first and they will sell well. Maybe if we are lucky they will do an RS version a couple of years later. It will weigh more than 520Lbs.

What do you think?

Modern bikes much more powerful. Power to weight ratio so much higher.

Zitat von Vtbob im Beitrag #19

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What do you think?

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Here’s an nteresting thing.

I took my 98 900ssie Ducati out for a run today - did about 80 miles or so (riding position is torture, so don’t usually do much more than a tank full in one hit...).

Now this bike weighs less than 180kg, about 56kg less than my RS. You really notice the lack of weight when pushing the Duc around the garage and drive......feels like I’m moving a mountain bike around compared to the RS.

Here’s the thing though, once moving at anything more than 2-3 mph, the RS is way more agile than the Duc, it’s better balanced, the brakes are better and it’s much easier to change direction. I suspect this has a lot to do with geometry and c of g, but for me, it makes a point that light weight alone is not always the key to agility and a sporty ride.

Zitat von MrVvrroomm im Beitrag #20

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Modern bikes much more powerful. Power to weight ratio so much higher.

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Interestingly, the Duc has a power to weight ratio of 2.25 (kg per bhx) on 80bhp and would only need 96bhp to match the RS (1.88kg per bhp).

Now give me a 180kg RS and there would be no need for a 150bhp vvt boxer as it would have a better ptw ratio than the vvt bike (assuming the vvt bike will weigh the same at 236kg). I suspect it is cheaper for BMW to increase power than to loose weight!

I guess this is why the Duc feels quite “punchy” even though it is low on bhp by modern standards.

Zitat von Mr. 36654 im Beitrag #21

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Zitat von Vtbob im Beitrag #19

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What do you think?

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Well, my 1986 K75c would weight about the same as my 2016 R1200RS. The difference in power is 50~55 HP.

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Zitat von GordonH im Beitrag #22

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Here’s an nteresting thing.

I took my 98 900ssie Ducati out for a run today - did about 80 miles or so (riding position is torture, so don’t usually do much more than a tank full in one hit...).

Now this bike weighs less than 180kg, about 56kg less than my RS. You really notice the lack of weight when pushing the Duc around the garage and drive......feels like I’m moving a mountain bike around compared to the RS.

Here’s the thing though, once moving at anything more than 2-3 mph, the RS is way more agile than the Duc, it’s better balanced, the brakes are better and it’s much easier to change direction. I suspect this has a lot to do with geometry and c of g, but for me, it makes a point that light weight alone is not always the key to agility and a sporty ride.

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Add 5 gallons of gas, at 6.6lbs/gallon, and the 517 goes to 550-lbs.

Zitat von TimMc im Beitrag #26

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Zitat von GordonH im Beitrag #22

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Here’s an nteresting thing.

I took my 98 900ssie Ducati out for a run today - did about 80 miles or so (riding position is torture, so don’t usually do much more than a tank full in one hit...).

Now this bike weighs less than 180kg, about 56kg less than my RS. You really notice the lack of weight when pushing the Duc around the garage and drive......feels like I’m moving a mountain bike around compared to the RS.

Here’s the thing though, once moving at anything more than 2-3 mph, the RS is way more agile than the Duc, it’s better balanced, the brakes are better and it’s much easier to change direction. I suspect this has a lot to do with geometry and c of g, but for me, it makes a point that light weight alone is not always the key to agility and a sporty ride.

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Modern tyres...?

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Zitat von MexicoMike im Beitrag #23

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Well, true pretty much but my old '73 Commando can still out-acclearate most current Harley Davidsons and weighs half as much.

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Zitat von GordonH im Beitrag #24

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Interestingly, the Duc has a power to weight ratio of 2.25 (kg per bhx) on 80bhp and would only need 96bhp to match the RS (1.88kg per bhp).

Now give me a 180kg RS and there would be no need for a 150bhp vvt boxer as it would have a better ptw ratio than the vvt bike (assuming the vvt bike will weigh the same at 236kg). I suspect it is cheaper for BMW to increase power than to loose weight!

I guess this is why the Duc feels quite “punchy” even though it is low on bhp by modern standards.

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