Bicycle comfort is it a dream?

Jdsk
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Re: Bicycle comfort is it a dream?

Post by Jdsk »

jois wrote: 28 Sep 2022, 2:06am
Jdsk wrote: 28 Sep 2022, 1:10am
jois wrote: 28 Sep 2022, 1:01amI'm still waiting for an alternate explanation of how I can increase the load on the front wheel by 30lbs and not have the same reactive normal force through my arms ?
The explanation of how the force is distributed will follow when you feel able to discuss how the "weight through your arms" gets to the front wheels.

I think that it's through the bars and the frame and the wheels.
I think I confirm the chain a few posts ago
I can't see that. Where is it please?

Or, to save time, perhaps we can agree that it's through the bars and the frame and the wheels and we can move on to the analysis.

Thanks

Jonathan
jois
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Re: Bicycle comfort is it a dream?

Post by jois »

Jdsk wrote: 28 Sep 2022, 2:10am
jois wrote: 28 Sep 2022, 2:06am
Jdsk wrote: 28 Sep 2022, 1:10am
The explanation of how the force is distributed will follow when you feel able to discuss how the "weight through your arms" gets to the front wheels.

I think that it's through the bars and the frame and the wheels.
I think I confirm the chain a few posts ago
I can't see that. Where is it please?

Or, to save time, perhaps we can agree that it's through the bars and the frame and the wheels and we can move on to the analysis.

Thanks

Jonathan
Just before the one where i explained press ups to you
Jdsk
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Re: Bicycle comfort is it a dream?

Post by Jdsk »

This?

"You may as well say if not through the stem or the frame or the forks or the wheel spindle or the tyres."

No reference to bars there.

The load from the arms goes through the bars, the frame and the wheels?

Agreed?

Thanks

Jonathan
rfryer
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Re: Bicycle comfort is it a dream?

Post by rfryer »

Another key point on weight distribution is that you measure weight on the wheels while stationary. However, once you start pedaling, the force on your arms will be reduced by the force you're putting through the pedals.

When cycling, the force on your arms is determined by position on the bike, gradient and braking/pedaling effort. I can't see how measuring weight through the wheels while static yields any useful information about arm pressure.
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Paulatic
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Re: Bicycle comfort is it a dream?

Post by Paulatic »

jois wrote: 28 Sep 2022, 1:01am
I'm still waiting for an alternate explanation of how I can increase the load on the front wheel by 30lbs and not have the same reactive normal force through my arms ?
Simply take your hands of the bars ( no weight at all on them now is there.) and then move your body forward along the cross bar. Watch that front scale rise :D
or
Back to your wheelie when climbing a very steep hill and the front wheel wants to lift don’t you naturally lean forward to put more weight on the front wheel. Did it all go through your arms?
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Re: Bicycle comfort is it a dream?

Post by Vorpal »

jois wrote: 28 Sep 2022, 1:01am
I'm describing what I said in my opening posts, I've been consistently repeating the same thing. If you want to call it reactive normal forces that's ok with me il call it % of body weight

I'm still waiting for an alternate explanation of how I can increase the load on the front wheel by 30lbs and not have the same reactive normal force through my arms ?
If you just go from sitting on the saddle to standing on the pedals, your weight transfers forward because the saddle is somewhat behind the pedals. Then the reactive force is taken by the pedals (or at least the one with the most weight). It is possible to do that without putting any additional force through your hands. Whether that amounts to 30 pounds depends on the bike set-up and cyclist weight. I imagine that just standing up, most of us will go from something like 60 / 40 to 55 / 45, which probably won't amount to 30 pounds. But cycling uphill, most of us lean forward, and not only will that put yet more weight on the front wheel, but they may reduce, rather than increase the weight on the bars. Many people pull up, cycling up hill.

I have climbed hills steep enough that it was hard to keep enough weight on the back wheel for traction.

For example,
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jois
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Re: Bicycle comfort is it a dream?

Post by jois »

Paulatic wrote: 28 Sep 2022, 8:00am
jois wrote: 28 Sep 2022, 1:01am
I'm still waiting for an alternate explanation of how I can increase the load on the front wheel by 30lbs and not have the same reactive normal force through my arms ?
Simply take your hands of the bars ( no weight at all on them now is there.) and then move your body forward along the cross bar. Watch that front scale rise :D
or
Back to your wheelie when climbing a very steep hill and the front wheel wants to lift don’t you naturally lean forward to put more weight on the front wheel. Did it all go through your arms?
When you say move my body along the cross bar do you mean sit on the cross bar or lean forward

Yes of course it went through my arms. There is other way for it to get there .
leaning forward lowers the centre of gravity it doesn't move weigh forward or backwards

And leaning forward put more weight on my arms. It has to do
Last edited by jois on 28 Sep 2022, 9:17am, edited 1 time in total.
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Re: Bicycle comfort is it a dream?

Post by jois »

Vorpal wrote: 28 Sep 2022, 8:47am
jois wrote: 28 Sep 2022, 1:01am
I'm describing what I said in my opening posts, I've been consistently repeating the same thing. If you want to call it reactive normal forces that's ok with me il call it % of body weight

I'm still waiting for an alternate explanation of how I can increase the load on the front wheel by 30lbs and not have the same reactive normal force through my arms ?
If you just go from sitting on the saddle to standing on the pedals, your weight transfers forward because the saddle is somewhat behind the pedals. Then the reactive force is taken by the pedals (or at least the one with the most weight). It is possible to do that without putting any additional force through your hands. Whether that amounts to 30 pounds depends on the bike set-up and cyclist weight. I imagine that just standing up, most of us will go from something like 60 / 40 to 55 / 45, which probably won't amount to 30 pounds. But cycling uphill, most of us lean forward, and not only will that put yet more weight on the front wheel, but they may reduce, rather than increase the weight on the bars. Many people pull up, cycling up hill.

I have climbed hills steep enough that it was hard to keep enough weight on the back wheel for traction.

For example,
But if I'm standing up and pushing the pedals using body weight I'm also pulling up on the bars which lighten the weight on the front wheel. And loads the back Well it does when I do it. It may be different with drop bars. But it was whilst sitting I was talking about
jois
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Re: Bicycle comfort is it a dream?

Post by jois »

rfryer wrote: 28 Sep 2022, 5:11am Another key point on weight distribution is that you measure weight on the wheels while stationary. However, once you start pedaling, the force on your arms will be reduced by the force you're putting through the pedals.

When cycling, the force on your arms is determined by position on the bike, gradient and braking/pedaling effort. I can't see how measuring weight through the wheels while static yields any useful information about arm pressure.
No I don't think it will. I'm not reducing body weight on my arms by pedling. I'm not in increasing or decreasing the weight of the bike or rider by pedling. There is air pressure but I don't go that fast
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Re: Bicycle comfort is it a dream?

Post by jois »

Jdsk wrote: 28 Sep 2022, 2:22am This?

"You may as well say if not through the stem or the frame or the forks or the wheel spindle or the tyres."

No reference to bars there.

The load from the arms goes through the bars, the frame and the wheels?

Agreed?

Thanks

Jonathan
No the bit where I confirmed there was a chain, by saying " its a chain"
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Re: Bicycle comfort is it a dream?

Post by Vorpal »

jois wrote: 28 Sep 2022, 8:54am
Vorpal wrote: 28 Sep 2022, 8:47am
jois wrote: 28 Sep 2022, 1:01am
I'm describing what I said in my opening posts, I've been consistently repeating the same thing. If you want to call it reactive normal forces that's ok with me il call it % of body weight

I'm still waiting for an alternate explanation of how I can increase the load on the front wheel by 30lbs and not have the same reactive normal force through my arms ?
If you just go from sitting on the saddle to standing on the pedals, your weight transfers forward because the saddle is somewhat behind the pedals....
But if I'm standing up and pushing the pedals using body weight I'm also pulling up on the bars which lighten the weight on the front wheel. And loads the back Well it does when I do it. It may be different with drop bars. But it was whilst sitting I was talking about
I don't think that you can shift that much weight forward whilst sitting. I'm not sure I understand what you are getting at.
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jois
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Re: Bicycle comfort is it a dream?

Post by jois »

Vorpal wrote: 28 Sep 2022, 11:12am
jois wrote: 28 Sep 2022, 8:54am
Vorpal wrote: 28 Sep 2022, 8:47am

If you just go from sitting on the saddle to standing on the pedals, your weight transfers forward because the saddle is somewhat behind the pedals....
But if I'm standing up and pushing the pedals using body weight I'm also pulling up on the bars which lighten the weight on the front wheel. And loads the back Well it does when I do it. It may be different with drop bars. But it was whilst sitting I was talking about
I don't think that you can shift that much weight forward whilst sitting. I'm not sure I understand what you are getting at.
It has a got a little confusing as I'm replying to somewhat off what I said originally posts

If bike and body weigh 220 lbs, that's it you cant make it heaver or lighter all you can do is move the weight around,, if your on a sit up and beg bike all your body weight is going through your bum. If you stand up to ped then all you body weight is going through your legs if your also pulling up on the bars. The bike still weighs 220lbs

If you want to put more weight on the front wheel the only way to do that is put more weight on your arms.. just leaning forwards no hands makes the centre of gravity lower the weight on your bum stay stays exactly at you body weight. You still weigh the same no matter what inclination you have
Jdsk
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Re: Bicycle comfort is it a dream?

Post by Jdsk »

jois wrote: 28 Sep 2022, 11:28amIf you want to put more weight on the front wheel the only way to do that is put more weight on your arms.. just leaning forwards no hands changes the centre of gravity forwards the weight on your bum stay stays exactly at you body weight. You still weigh the same no matter what inclination you have
Keeping your arms off the bars ("no hands") throughout: when you lean forward what happens to the reading on the scales under the front wheels and the reading on the scales under the rear wheels?

Thanks

Jonathan
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Re: Bicycle comfort is it a dream?

Post by Nearholmer »

I think I might understand what Jois is driving at.

I have two bikes (well, two that I use regularly!). My "shopping bike" has wide, flattish bars, a generally "sit up straight" geometry, and a big wide, sprung B67 seat. My "proper bike" has gravel-type, geometry, flared drops, and a much narrower C15 seat.

On the sportier bike I can move about all over the place, transfer weight onto or off of the front wheel, stand-up, lean forward, sit down, slide back, anything I can manage, and that bike can be got across all sorts of ground, and up any hill that my (pretty poor) fitness will permit, even if the going is pretty bumpy.

The shopping bike is a horse of a different colour. You can stand up and go hard at it, but its a complete waste of effort, and its nigh-on impossible to put weight over the front wheel, or to unload the front by sliding back. There is only one way to ride: sitting down, and treading along sedately. When I borrow my son's 29er MTB, I find it extremely challenging to get weight on the front wheel with that too, even with the suspension locked. In both cases it is very easy to accidentally start unloading the front wheel, lifting it off the ground, and in both cases my feeling is that the handlebars are too far back to facilitate throwing weight to the front - you can do it, but it involves leaning the body forward of the hands, which feels unstable, and definitely doesnt come naturally to me.

If that is the issue, I dont know the answer, although experienced MTBers might, although I suspect even they may not, because the geometry of modern MTBs, and some hybrids, is all about stability and controllability when going fast downhill, and they tend to sit down and twiddle in a very low gear when going up steep hills (which is the best thing to go if the ground is loose anyway, because leaning forward can unload the back and cause wheelspin).

I hope this isnt an entirely irrelevant ramble off the point!

PS: on a drop bar bike you can unload the front by leaning forward while taking virtually no weight through the arms. Simply stand-up and lean while holding the hoods very loosely, supporting your body through your core muscles, not your arms. Its sometimes a good technique going slowly on rough ground, because then the front wheel finds its own way around/through small lumps and bumps, whereas if you put weight on your arms that tends to cause you to "fight" the front wheel.
Last edited by Nearholmer on 23 Oct 2022, 6:17pm, edited 2 times in total.
Jdsk
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Re: Bicycle comfort is it a dream?

Post by Jdsk »

Jdsk wrote: 28 Sep 2022, 11:32am
jois wrote: 28 Sep 2022, 11:28amIf you want to put more weight on the front wheel the only way to do that is put more weight on your arms.. just leaning forwards no hands changes the centre of gravity forwards the weight on your bum stay stays exactly at you body weight. You still weigh the same no matter what inclination you have
Keeping your arms off the bars ("no hands") throughout: when you lean forward what happens to the reading on the scales under the front wheels and the reading on the scales under the rear wheels?
I've just done the experiment.

: - )

Jonathan
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