Hypothetical frame ...
 

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[Closed] Hypothetical frame and wheel weight question

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Something I wonder about quite often lately.

Say we have two bikes, A and B, on flowing single trail going slightly downhill, but not much.

These bikes only have frames/forks and wheels nothing else.

Bike A: Frame weight 1kg, wheels weight 9kg (total 10kg bike weight)
Bike B: Frame weight 9kg, wheels weight 1kg (total 10kg bike weight)

How would the ride characteristics differ going around bends and corners? Which one would be best for say going around a long smooth bend at say 30km/r?

Thanks!


 
Posted : 30/07/2013 10:42 pm
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30km/r?

What?

Also I'd hazard that they'd both be awful, not having handlebars and all.


 
Posted : 30/07/2013 10:54 pm
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Which one would be best for say going around a long smooth bend at say 30km/r?

Is it on a conveyor belt?


 
Posted : 30/07/2013 10:57 pm
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sorry i meant 30 km/h 🙂

well you can picture with handlebars if you like!

just trying to get an idea of how performance will be affected by more mass in the wheels vs more mass in the frame/body or 'center' of teh bike 😉


 
Posted : 30/07/2013 10:57 pm
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Take your tyre off your front wheel, hold the bike in the air, spin the wheel fast, turn the bars about. Repeat with the tyre back on.


 
Posted : 30/07/2013 10:59 pm
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I love this forum. I haven't laughed this much in ages. Kukonaya you are a genius.

I cannot in all seriousness answer you question but keep posting please.


 
Posted : 30/07/2013 11:01 pm
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Take your tyre off your front wheel, hold the bike in the air, spin the wheel fast, turn the bars about. Repeat with the tyre back on.

thanks, i have not considered the impact of angular momentum. would that have a big impact in how the bike handles then?

What I am really after is where it would be best to cut weight off my bike. If I replace my frame with something thats 1kg lighter vs replace wheels with wheels that are 1kg lighter - which would be the best option for single track?

Thanks!


 
Posted : 30/07/2013 11:12 pm
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Keep going until you have a negative weight in the wheels


 
Posted : 30/07/2013 11:13 pm
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Ever thought about riding a unicycle?, or doing away with the bike altogether and just go for a run?.


 
Posted : 30/07/2013 11:14 pm
 Drac
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More importantly what tags is the riding wearing?


 
Posted : 30/07/2013 11:14 pm
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Keep going until you have a negative weight in the wheels

thanks mike, do you mean that lighter wheels are always better than the same weight saved on a frame for example?

i thought so too, at first. but i am interested in the steering response. take fo example a car - at high speeds on a curvy country road you do not want super light steering right? its better for the steering to be a bit 'heavy'. some cars like BMW's? servotronic I think would actually make the steering less sensitive at higher speeds.


 
Posted : 30/07/2013 11:20 pm
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thanks mike, do you mean that lighter wheels are always better than the same weight saved on a frame for example?

No just keep shaving weight off them until they weigh less than 0kg.


 
Posted : 30/07/2013 11:23 pm
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Ever thought about riding a unicycle?, or doing away with the bike altogether and just go for a run?.

I am a HORRIBLE runner! I have a bit of a bad back and herniated disc, too much running can result in a massive sciatic flare up! 🙂


 
Posted : 30/07/2013 11:23 pm
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No just keep shaving weight off them until they weigh less than 0kg.

i dont follow 😛


 
Posted : 30/07/2013 11:24 pm
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Why not take into consideration the pressure and volume of the tyres? If Air weighs about 1.15g per litre at sea level with an atmospheric pressure of 14.7 PSI the rotational weight on your bike will increase with higher pressures/larger volumes.

In all seriousness to the OP's question i have no idea. Im guessing the lighter wheels will feel more agile on a twisty trail but in a straight line they will probably feel the same.


 
Posted : 30/07/2013 11:49 pm
 JoeG
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OP - ride a set course timing yourself with your normal air pressure in the tires. Then fill your tires with water and repeat...

If you would fill your tires with helium for the first run, and mercury for the second the difference would be even more noticeable! :mrgreen:


 
Posted : 31/07/2013 2:17 am
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Tubeless with helium will make a huge difference. Especially if you use ELSA tyres.


 
Posted : 31/07/2013 9:22 am
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4.5kg per wheel - the gyroscopic forces will make them horrible to turn. But once rolling in a straight line they would go be less susceptible to bumps making them slow down.

1kg wheels - will probably collapse as almost half that would be the tyres.


 
Posted : 31/07/2013 9:29 am

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