Extended swing arms / longer wheel base

[AussieJester]

Then add to that the added weight of the swing arm.....

How does the weight of the swingarm get added to the problem? It is UNSPRUNG weight sitting on the axle. Not effecting the shock/spring as far as I can see?

Perhaps take a 30lb frocked bike over some rough ground and
then a standard wheeled bike and you will soon see the difference it makes
Gordo alot more weight is being
pushed upwards at the end of the swing arm when the wheel
rolls over a bump, the standard shock isn't designed to
handle this, suspension is not all for comfort but to keep the
rear wheel in contact with the ground, the shock is
there to push the wheel back down as much as it is to damper the effect of the upward
motion of the rear wheel, with more weight hanging off the end of the swing
arm the standard shock isnt able to push the wheel back down quick enough
as it is meant to do.....

KiM

 

[Gordo]

Then add to that the added weight of the swing arm.....

How does the weight of the swingarm get added to the problem? It is UNSPRUNG weight sitting on the axle. Not effecting the shock/spring as far as I can see?

Perhaps take a 30lb frocked bike over some rough ground and
then a standard wheeled bike and you will soon see the difference it makes
Gordo alot more weight is being
pushed upwards at the end of the swing arm when the wheel
rolls over a bump, the standard shock isn't designed to
handle this, suspension is not all for comfort but to keep the
rear wheel in contact with the ground, the shock is
there to push the wheel back down as much as it is to damper the effect of the upward
motion of the rear wheel, with more weight hanging off the end of the swing
arm the standard shock isnt able to push the wheel back down quick enough
as it is meant to do.....

KiM

Mate,
YOu are wrong. Think of adding 1000 lbs or 10,000lbs on the end of the swing arm. As you increase this weight, does it push up more? Weight is gravity.

 

[AussieJester]

I never said it pushed up more Gordo, i said with the extra weight the standard shock isn't able to push
the wheel down as fast as it should to stay in contact with the ground, there are many on this site that have
full suspension mtbs and have posted that the weight does affect the suspension they must all be wrong too then
are they?....

I guess we shall just have to agree to disagree on this one then Gordo... :wink:

KiM

EdiT: not the best reference site but explains it better than i

" a lighter wheel which readily moves in response to road bumps will have more grip and more constant grip when tracking over an imperfect road. For this reason, lighter wheels are sought especially for high-performance applications. In contrast, a heavier wheel which moves less will not absorb as much vibration; the irregularities of the road surface will transfer to the cabin through the geometry of the suspension and hence ride quality and road noise are deteriorated. For longer bumps that the wheels follow, greater unsprung mass causes more energy to be absorbed by the wheels and makes the ride worse."

http://en.wikipedia.org/wiki/Unsprung_mass

Perhaps a more crediable site may convince you im right Gordo LoL

"The less weight hanging from the suspension components, the easier it is for the mass of the wheels to stop and accelerate in the opposite direction"

http://www.mb1suspension.com/id102.html


I could link more they all say the same thing more weight on the swing arm decreases the performance of the suspension...Sorry buddy, your wrong

 

[zombiess]

Good news, dropped off my spare swing arm to my fabricator, he's going to add 8" to it hopefully this weekend. Gave him some basic blue prints of what I wanted done. Wheel base is going from 37" to 46", should be much less wheelie happy now, just some fun 2-6" power wheelies

Front suspension is now going to have 4" of travel, spring preload and compression adjustable with hydraulic lockout. Rear swing arm about 6" of travel with 750lb spring and adjustable rebound. This bike should ride nice.

 

[Pure]

What you are saying does make sense Gordo, but every model of suspension I've seen working, the wheel pushes up. The car/bike/what ever doesn't push down. This is what has me confused with what you are saying. That mass traveling has to be controlled and our little shocks are not meant or built with enough mass to really be able to withstand that or at best we are pushing them to their limits.

No worries man, no offence taken.

 

[Gordo]

I never said it pushed up more Gordo, i said with the extra weight the standard shock isn't able to push
the wheel down as fast as it should to stay in contact with the ground, there are many on this site that have
full suspension mtbs and have posted that the weight does affect the suspension they must all be wrong too then
are they?....

I guess we shall just have to agree to disagree on this one then Gordo... :wink:

KiM

EdiT: not the best reference site but explains it better than i

" a lighter wheel which readily moves in response to road bumps will have more grip and more constant grip when tracking over an imperfect road. For this reason, lighter wheels are sought especially for high-performance applications. In contrast, a heavier wheel which moves less will not absorb as much vibration; the irregularities of the road surface will transfer to the cabin through the geometry of the suspension and hence ride quality and road noise are deteriorated. For longer bumps that the wheels follow, greater unsprung mass causes more energy to be absorbed by the wheels and makes the ride worse."

http://en.wikipedia.org/wiki/Unsprung_mass

Perhaps a more crediable site may convince you im right Gordo LoL

"The less weight hanging from the suspension components, the easier it is for the mass of the wheels to stop and accelerate in the opposite direction"

http://www.mb1suspension.com/id102.html

I could link more they all say the same thing more weight on the swing arm decreases the performance of the suspension...Sorry buddy, your wrong

Kim,
Every reference you post is 100% correct. But have you been watching your turd go down the loo counterclockwise, because you live on the bottom side of the planet? The fact that heavier suspension is bad, less unsprung weight is good for ride and control, has nothing to do with the force on the attachment point of the spring. The strength of the spring and the attachment point is governed by the SPRUNG WEIGHT. Perhaps if you consider the impossible case, where the rest of the bike and rider has ZERO weight, the hub motor weighs 1000 lbs, then tell me how strong would the spring need to be to stop the hubmotor from damaging the attachement point on the ZERO weight bike? Now make the hubmotor/swingarm ZERO and consider the strength of the spring and attachment point needed? Do you now need a ZERO strength spring? Only the sprung weight of the bike and rider needs to be considered, not the swingarm weight.
Another suggestion; Think of 2 identical vertical springs with 10 lb weights on top, but one has a 10 lb weight underneath while the other has a 100 lb weight underneath. Lift them up the same height and drop them. Which spring will compress more on impact? Which spring/weight combo will drop faster when you release them?
Do you remember Galileo? Maybe get your med's changed or quit with the self-medicating program?

Guys,
The one point I think some are missing here is that when you change a regular bike to a hubmotor bike, you need a SHOCK which provides many times the dampening to handle the huge % increase in unsprung weight. Don't change or increase the strength of the spring, because of the hubmotor, swingarm length. The size of the spring is dependent on the weight of the frame, battery and rider, not the hub and swingarm. There is no question increasing the unsprung weight means the wheel will fail to follow the ground contour as it did before a hubmotor and "be in the air half the time". For sure, my upside-down friend will wake-up and realize the benefit of a non-frocked scoot and tell us about it.
Now if I could only figure out why the guys down under don't walk on their hands to be upright?

 

[AussieJester]

Please quote where I said it made a difference to the attachment point Gordo?
Obviously we were talking about two different things.here, I also don't see the need for the upside down references & me being from Australia simply because I mistook what you were talking about originally, but if you want to play that game I'm good at it too Godo, you grumpy old canook, your what happens as result of years of living under 27feet of snow years in years out I presume, would likely piss me off too...enjoy your 3 fine months of the year now wont you OLD man.

KiM

 

[thepronghorn]

You forget that it's currently fall in Canada and rapidly progressing towards winter. Anyways it's interesting that you are so grumpy considering it's spring going on summer down in the southern hemisphere.

 

[Gordo]

Please quote where I said it made a difference to the attachment point Gordo?
Obviously we were talking about two different things.here, I also don't see the need for the upside down references & me being from Australia simply because I mistook what you were talking about originally, but if you want to play that game I'm good at it too Godo, you grumpy old canook, your what happens as result of years of living under 27feet of snow years in years out I presume, would likely piss me off too...enjoy your 3 fine months of the year now wont you OLD man.

KiM

KiM,
I always believed you had a good sound reason for deriding frock motors. The unsprung weight reason. I'm surprised to learn this may be a mistaken belief on my part. I do not know much about bicycles or their shocks, but I do wonder if they do push back when compressed? I only know vehicle and motorcycle shocks, and they do not push back, unless they are an airshock, designed to hold up some of the load. So the shocks I know, depend on pushing oil from one chamber to the other through a small hole and/or valves to provide a dampening effect on the wheel assembly. They come in all configurations and provide different rates of up dampening, to down dampening. The shocks being used on frockmotors, seem totally inadequate for the weight of the assembly, especially with a 3" motorcycle tire. As someone pointed out, using a motorcycle shock is a good starting point. Cranking up the spring pressure, in a futile attempt to get the dampening needed, is useless. Doing this because the wheel weighs more, is faulty logic. None of this came from you, but it is in the discussion.
Sticking to your preferred frame mounted wizzers and staying away from frocks, makes total sense from the best ride point. I have always wondered what the 10KW hubmotors do to motorcycle handling? I know enough about unsprung weight to not try cornering a converted motorcycle on a bumpy road. Walking sideways off a corner can ruin your day.

As far as poking fun at your place of birth, you are the most practiced spear chucker on ES. So you are fair game. :lol:

We have had 5 months of summer this year and seldom see snow. Put the cover on the RV last week and transferred the license plates from the sports-car to the sedan today. We often dream of a "White Christmas" because the decorative lights look so much nicer in the snow. It did snow around here last week in areas above 1000m. In June, I've snow skied in the morning and water-skied in the afternoon, so this part of the Cold White North is not too hard to take. And we don't water-ski in 3/8" rubber suits except for Christmas and New Years. So yes, the 27' of snow will be on the ski hill in March, but I still have to cut the lawn a couple of more times before it quits growing.
We are fortunate to be able to spend our life anywhere we wish, but I prefer to be in my shop, with my tools and junk, to most places on this earth. We have done our share of sitting in the southern sun, with our finger in our ass and find it a gross waste of time.

Get out of here KiM and go build another chunk of motorized jewelry.
Peace, brother.