Motorcycle Roof Rack

[aeropilot]

einsign said:

Does something like this actually exist, if not why not?

Why not is simple.

For most cars, the weight would exceed the roof load limit. You won't find many family sized cars with a roof load limit greater than about 75-80kg, so even a lightweight trials bike would exceed the limit.

And given the implications on aerodynamics and loading, when there are better, and easier alternatives, everyone is correct in saying.........it's a fking stupid idea

[3DP]

Hooli said:

Mr Snap said:

But only in the minds of EU supporters...

Fixed that for you, it's the EU that likes top heavy unstable structures on dodgy foundations after all

Spot on

[einsign]

I believe Mr Snap supports the green party, who would ban all motorcycles and re-seed the roads if he had his way.

Edited by einsign on Monday 10th June 09:49

[einsign]

aeropilot said:

For most cars, the weight would exceed the roof load limit. You won't find many family sized cars with a roof load limit greater than about 75-80kg, so even a lightweight trials bike would exceed the limit.

And given the implications on aerodynamics and loading, when there are better, and easier alternatives, everyone is correct in saying.........it's a fking stupid idea

It boils down to knowing certain data before you can just say no:

1/ The torsional strength and shear loadings at the point of connection to the roof (depending on vehicle and method of connection)

2/ Most roof racks are crap and their maximum load is relevant to the racks strength, it has nothing to do with the load capacity of the vehicles roof connection points.

3/ Not even worth discussing for anything smaller than a medium/large size car.

4/ Aerodynamic and weight distribution issues, ie forces at connection points when turning etc.

5/ PH'er opinions.

[srob]

einsign said:

It boils down to knowing certain data before you can just say no:

1/ The torsional strength and shear loadings at the point of connection to the roof (depending on vehicle and method of connection)

2/ Most roof racks are crap and their maximum load is relevant to the racks strength, it has nothing to do with the load capacity of the vehicles roof connection points.

3/ Not even worth discussing for anything smaller than a medium/large size car.

4/ Aerodynamic and weight distribution issues, ie forces at connection points when turning etc.

5/ PH'er opinions.

I work for a car company. I've worked on most makes of car you'll see on the road at one time or another. I've never - not once - heard anyone ask at a design meeting whether anybody's allowed for some tit to selotape a motorbike to the top of the car.

So for that reason alone, I think you'd be better off funnelling your design desires into something a little more worthwhile.

Like a pair sunglasses for the man with one ear.

[redtwin]

srob said:

So for that reason alone, I think you'd be better off funnelling your design desires into something a little more worthwhile.

Like a pair sunglasses for the man with one ear.

Already done, clearly something more challenging is required.

[Mr Snap]

einsign said:

I believe Mr Snap supports the green party, who would ban all motorcycles and re-seed the roads if he had his way.

Edited by einsign on Monday 10th June 09:49

Mr Snap has a BMW R1100SS and doesn't want to do Sammy Miller impressions with it.

[sprinter1050]

Hasn't BikersNemesis been wishing for someone to design an ashtray for his bike..?

[Mr2Mike]

einsign said:

It boils down to knowing certain data before you can just say no:

1/ The torsional strength and shear loadings at the point of connection to the roof (depending on vehicle and method of connection)

2/ Most roof racks are crap and their maximum load is relevant to the racks strength, it has nothing to do with the load capacity of the vehicles roof connection points.

Irrelevant. The car manufacturer will give a maximum roof load which is independent of any roof rack limitation, and around 75kg is a common figure.

[bass gt3]

Mr2Mike said:

einsign said:

It boils down to knowing certain data before you can just say no:

1/ The torsional strength and shear loadings at the point of connection to the roof (depending on vehicle and method of connection)

2/ Most roof racks are crap and their maximum load is relevant to the racks strength, it has nothing to do with the load capacity of the vehicles roof connection points.

Irrelevant. The car manufacturer will give a maximum roof load which is independent of any roof rack limitation, and around 75kg is a common figure.

And this is because the roof rack and load when in motion will have inertia. If you have a sudden deceleration from speed in an acccident, you now have a 120/200kg load subjected to high G deceleration forces. These forces are transmitted to the vehicle via the rack mounting points, especially compounded as the moment or movement/fulcrum is so high due to the bike being upright. The bike's weigh/CoG will exert an amplified force onto the racks mounting points which causes a lever effect amplifing the forces on the roof rack mounting points which will result in catastrophic failure.
You now have a 120/200kg projectile flung from the roof of the car which might be detrimental to the health and well being of other persons in the vicinity.Is this a possible problem???
So whilst the airbag saved you from the impact, you were killed by the motorcycle coming through into the passenger area that fked you. Does this sound like a problem??
Seriously, you seem to refuse any and all quantitive evidence as to why such a device could not be made commercially available due to the inherent safety issues. Some home hashed bodge job is not acceptable as a solution, as such a bodge would be illegal, so proper type approval would be required. For all the reasons listed, and predominately/fundamentally the Laws of Physics this is not viable proposition, yet you persit with this fking stupid idea thinking if we just think harder,run st up the flag pole, think outsie the fking box we'll crack it.
So try doing some serious maths on the matter and then ask yourself these idiotic questions again.
But in reality, you're being a tt now. Stop it

Edited by bass gt3 on Monday 10th June 11:12

[Mr Snap]

bass gt3 said:

Mr2Mike said:

einsign said:

It boils down to knowing certain data before you can just say no:

1/ The torsional strength and shear loadings at the point of connection to the roof (depending on vehicle and method of connection)

2/ Most roof racks are crap and their maximum load is relevant to the racks strength, it has nothing to do with the load capacity of the vehicles roof connection points.

Irrelevant. The car manufacturer will give a maximum roof load which is independent of any roof rack limitation, and around 75kg is a common figure.

And this is because the roof rack and load when in motion will have inertia. If you have a sudden deceleration from speed in an acccident, you now have a 120/200kg load subjected to high G deceleration forces. These forces are transmitted to the vehicle via the rack mounting points, especially compounded as the moment or movement/fulcrum is so high due to the bike being upright. The bike's weigh/CoG will exert an amplified force onto the racks mounting points which causes a lever effect amplifing the forces on the roof rack mounting points which will result in catastrophic failure.
You now have a 120/200kg projectile flung from the roof of the car which might be detrimental to the health and well being of other persons in the vicinity.Is this a possible problem???
So whilst the airbag saved you from the impact, you were killed by the motorcycle coming through into the passenger area that fked you. Does this sound like a problem??
Seriously, you seem to refuse any and all quantitive evidence as to why such a device could not be made commercially available due to the inherent safety issues. Some home hashed bodge job is not acceptable as a solution, as such a bodge would be illegal, so proper type approval would be required. For all the reasons listed, and predominately/fundamentally the Laws of Physics this is not viable proposition, yet you persit with this fking stupid idea thinking if we just think harder,run st up the flag pole, think outsie the fking box we'll crack it.
So try doing some serious maths on the matter and then ask yourself these idiotic questions again.
But in reality, you're being a tt now. Stop it

Edited by bass gt3 on Monday 10th June 11:12

I think you misunderstand, Bass. OP isn't trying to create a mobile bike carrier, it's conceptual art.

In which case, there are no wrong answers.

[Fleegle]

What a waste of bandwidth

[einsign]

srob said:

I work for a car company.

Doing what, roofrack engineer?

[einsign]

Mr2Mike said:

Irrelevant. The car manufacturer will give a maximum roof load which is independent of any roof rack limitation, and around 75kg is a common figure.

Can you show me the data, or did you just make up the 75kg figure?

[blugnu]

Could one perhaps attach the motorbike to the side of the car with a sort of outrigger arrangement instead?

[Hooli]

einsign said:

srob said:

I work for a car company.

Doing what, roofrack engineer?

Last time I saw one of that company's cars with a roof rack, 007 was driving it with skis on the roof

[srob]

einsign said:

srob said:

I work for a car company.

Doing what, roofrack engineer?

No.

But I did do a mechanical design apprenticeship with an OEM, and cars have roofs, so they were a little hard to ignore.

[Fleegle]

einsign said:

Mr2Mike said:

Irrelevant. The car manufacturer will give a maximum roof load which is independent of any roof rack limitation, and around 75kg is a common figure.

Can you show me the data, or did you just make up the 75kg figure?

How about doing your own bit off digging, you fking irritant

[Vapour]

Dude just get a trailer!

[3DP]

bass gt3 said:

Mr2Mike said:

einsign said:

It boils down to knowing certain data before you can just say no:

1/ The torsional strength and shear loadings at the point of connection to the roof (depending on vehicle and method of connection)

2/ Most roof racks are crap and their maximum load is relevant to the racks strength, it has nothing to do with the load capacity of the vehicles roof connection points.

Irrelevant. The car manufacturer will give a maximum roof load which is independent of any roof rack limitation, and around 75kg is a common figure.

And this is because the roof rack and load when in motion will have inertia. If you have a sudden deceleration from speed in an acccident, you now have a 120/200kg load subjected to high G deceleration forces. These forces are transmitted to the vehicle via the rack mounting points, especially compounded as the moment or movement/fulcrum is so high due to the bike being upright. The bike's weigh/CoG will exert an amplified force onto the racks mounting points which causes a lever effect amplifing the forces on the roof rack mounting points which will result in catastrophic failure.
You now have a 120/200kg projectile flung from the roof of the car which might be detrimental to the health and well being of other persons in the vicinity.Is this a possible problem???
So whilst the airbag saved you from the impact, you were killed by the motorcycle coming through into the passenger area that fked you. Does this sound like a problem??
Seriously, you seem to refuse any and all quantitive evidence as to why such a device could not be made commercially available due to the inherent safety issues. Some home hashed bodge job is not acceptable as a solution, as such a bodge would be illegal, so proper type approval would be required. For all the reasons listed, and predominately/fundamentally the Laws of Physics this is not viable proposition, yet you persit with this fking stupid idea thinking if we just think harder,run st up the flag pole, think outsie the fking box we'll crack it.
So try doing some serious maths on the matter and then ask yourself these idiotic questions again.
But in reality, you're being a tt now. Stop it

Edited by bass gt3 on Monday 10th June 11:12

Like I said - in marketing.

All I'm hearing is excuses. I want to see solutions, not problems, damn it.