Suspension

[Chalo]

http://endless-sphere.com/forums/viewtopic.php?f=1&t=48946&start=50#p739421

After the switch, I noticed two things while test riding: One was that I had to dramatically lower the front tire pressure to have the same perceived ride comfort on broken pavement-- where 40 psi worked great before, and kept the 60mm front tire stable on the 24mm wide rim, I had to lower the pressure to 25 psi to yield equivalent ride quality with the rigid fork. But the new wheel's 38mm wide rim fattens the tire and keeps it stable at very low pressure, and the new setup is 2-1/2 pounds lighter even with the much bigger, heavier rim.

how much energy is required to travel on half-flat tyres ?

1. more
B. less

and slower max speed as a bonus.

Here's another thing I immediately noticed: none of the bob I had become accustomed to over the last few years. So whenever I accelerate, climb, or just pedal hard to maintain a nice high speed, the bike is now noticeably more responsive and faster with the rigid fork. There is surely a little more rolling resistance with lower front tire pressure, but that is the way Schwalbe Big Apples are designed to be used. It's certainly less than the 5% or more gross penalty incurred by my fork while pedaling hard, a number that represents the percentage of each pedal stroke used just to move the bike up and down.

Crank diameter 380mm
Vertical distance of forceful pedal stroke approx 300mm
Fork movement under hard seated pedaling approx 38mm
Ratio of chainstay length to wheelbase 0.4
38mm / 300mm * 0.4 = 5.07%

According to the power calculator, switching from a wide high-pressure slick to a mountain bike knobby on the front costs about the same 5% at a steady 20mph. But just lowering the same fat slick from 40psi to 25psi won't make that kind of difference.

Thus if you can't bear to pedal and only use motor power, a soft tire probably costs you a little speed and energy (while it adds traction and wear life). But if you pedal hard at any point, you lose more than that to squishing the suspension (especially if you stand to pedal).

I'm happy to accept even greater than 5% efficiency cost for some things, like a multi-speed pedal drive. But if I can avoid such energy loss while reducing weight, increasing reliability and durability, improving traction, and still enjoying the very same benefits as the mechanical suspension provided for the conditions I ride in, it seems like a win to me.

 

[full-throttle]

Fork movement under hard seated pedaling approx 38mm

You're doing something wrong, either you pedalling technique is crap or your fork has no compression damping or both
Rigid fork will only mask the problems with technique. If you notice that much movement rigid fork is not the cure.

Pedalling my DH bike to the top of the shuttle, up a 16% hill, standing up on the pedals, there's about 5mm of bob. I can take a video to prove it.

 

[Chalo]

Fork movement under hard seated pedaling approx 38mm

You're doing something wrong, either you pedalling technique is crap or your fork has no compression damping or both
Rigid fork will only mask the problems with technique. If you notice that much movement rigid fork is not the cure.

Pedalling my DH bike to the top of the shuttle, up a 16% hill, standing up on the pedals, there's about 5mm of bob. I can take a video to prove it.

I find that difficult to believe, because weight shift is weight shift, and that's what pedaling is. If you have a setup that sags 20-25% under your seated weight and has more than a couple of inches of travel, it seems to me like there would be no way to avoid much more bob than 5mm when shifting your weight enough to pedal hard, let alone standing. The onset of pedal strokes is quite gradual compared to impacts, and hydraulic damping of whatever quality doesn't hold its position against gradual loadings. Only stiction does that, and we don't like it.

Correct pedaling technique is the kind that propels you efficiently and intuitively, not what persuades your mechanical suspension to behave tolerably. The bike is to serve the rider and not the other way around.

5mm or even less movement is characteristic of what I get when I'm running at cruise speed. 30+ mm is what I get when I'm really jamming on it to surmount a short or steep incline, or to pull away from a stop. That's also when I appreciate efficiency the most, because I am making a hard effort.

My Marzocchi fork may be underdamped, because I stiffened the springs to the heaviest available (on a model without obvious compression damping adjustment) and only changed the fork oil to a slightly heavier weight to compensate. But its damping qualities don't feel significantly different under casual examination than the other expensive hydraulic forks I come across in the course of my work, or than the forks on my various motorcycles for that matter. Other forks on bicycles behave pretty much the same way when I try them, except that they sag a lot more and bottom out easily.

Meanwhile, any weight rider can use my fat tire rigid bike and enjoy the same ride qualities I do, with nothing more than tire pressure adjustments as necessary.

 

[full-throttle]

Correct pedaling technique is the kind that propels you efficiently and intuitively, not what persuades your mechanical suspension to behave tolerably.

So, you are saying YOUR pedaling technique that causes YOUR fork to bob 38mm is more efficient than mine?? Well, I've got real-world race results to prove how good mine is - couple of 1st places, a few top-5 and many top-10. Show me your race results.
Here's the video I posted on my thread a week ago. Some steep climbing @ 0:53~1:32 on a 160mm Fox 36 set up for descending. No lock-out, no alterations, camera on the bars.

I find that difficult to believe..

Yeah, I noticed that. You rather blame the tools than yourself for all the problems you come across:

My Marzocchi fork may be underdamped

In the other thread you wrote your weight is 280~410lbs. The heaviest spring Marzocchi offers for that model of fork is rated to 240lb max. So you're well over the limit there. Then you wrote you made a longer spacer. The spacer does NOT change the spring rate, only the initial force (preload) You need to better understand how the suspension is designed to work. On top of that you admit your fork is underdamped. Which is a 10yr old, non adjustable model BTW.

Seriously, what do you expect? Declare the war on suspension and the problem will go away? :lol:

 

[bowlofsalad]

Psh, this picture http://s7.postimg.org/gzcgg357f/Gfhds.jpg says the opposite.

 

[neptronix]

Psh, this picture http://s7.postimg.org/gzcgg357f/Gfhds.jpg says the opposite.

Congratulations, you win the argument! You win three internets points!

 

[Chalo]

In the other thread you wrote your weight is 280~410lbs. The heaviest spring Marzocchi offers for that model of fork is rated to 240lb max. So you're well over the limit there. Then you wrote you made a longer spacer. The spacer does NOT change the spring rate, only the initial force (preload) You need to better understand how the suspension is designed to work.

Well, the sag was correct and never once did I bottom it out, even hard on the brakes. That's enough spring rate in my book. I agree that adding preload alone doesn't help much, because it didn't help much with my motorcycles. The sag height would get a little better, but they'd still bottom out on bumps.

I think one of the factors there is that I am 6'8" tall with a 40" standing inseam, so my seat is very high. Since bikes don't get longer rear ends in proportion to their frame sizes, the weight distribution on a bicycle shifts rearward the taller the rider is. Whatever weight sits on the rear wheel can't push the fork down, so the load on the front at any given time may only have been equivalent to that of a short, mid-200 pounds rider with a more front-weighted distribution. Otherwise, I don't know why the spring would be so stiff if it's for a rider nearly 100 pounds lighter than me.

My Marzocchi fork is adjustable for rebound damping, but not compression damping. It's a 2004 model, but because it's a 29er I believe it's mechanically the same as a 2003 26" model. I don't know what the fork's age has to do with it, because it's not like telescopic forks are cutting edge technology, now or in 2003. Most of my other bikes and parts are much older than that, and for the most part they are better than the equivalent items available today.

I'll keep the fork around in case I come up with a good use for it, but for the moment I'm happy that my bicycle is a bicycle again. Less is more with these things. I'm old enough now that I don't think there are a lot of precipitous rock-strewn trails in my future. If there are, I can take them nice and easy. What works on busted-up city streets works for me, and fat tires will do it. Frankly, I suspect that many of the folks here who consider suspension "essential", "indispensable", etc., are not riding on surfaces any more challenging than the ones I face, or going any faster than I go on downhill stretches. They "need" suspension on their bicycles like they "need" cruddy OEM disc brakes or 100W LED headlights.

 

[biohazardman]

I commute via bike 3500-5000 miles a year and seldom drive. Riding an e-bike without suspension at 20+ MPH average speeds made me hurt. Doing the same with the 4" of travel at my usual 20-30MPH on my Trance does not. With all of the injuries suffered through my many years it's really nice to ride and not hurt after. Now I often ride for pleasure as well as commuting. Don't listen to the haters get the best full suspension you can afford put it together and just try to wipe the grin off your face after you ride.

 

[full-throttle]

Frankly, I suspect that many of the folks here who consider suspension "essential", "indispensable", etc., are not riding on surfaces any more challenging than the ones I face, or going any faster than I go on downhill stretches.

Anyone in particular?
Even if you suspicion is correct - it's their choice. Why does it bother you? Do you really think a rigid bike will make them faster or more comfortable?

 

[Kingfish]

Without full-suspension I would be crippled after a cross-country ride. In fact - I was:

Compare my 2010 trip to California on a hardtail (front suspension) to a FS in 2011, the differences were night and day.

Yes, I made a choice to go FS; it was that or wind up a casualty.

Why mock the choice? We're electrified rides that should - given our speed - have the best machine possible to maintain control. Hardtails do not give control; they beat you to death in a most unforgiving way.

Many years ago I owned a customized Honda Odyssey: Imagine a 4W ATV with front suspension like a VW, solid rear axle, balloon tires all around, and a full roll cage. After two years I sold it off because I was getting beat to death, and instead eyeballing the Honda Pilot for its' independent suspension. We don't drive cars without suspension; I don't even know if you can find one. Do they make motorcycles without suspension? What does that say about choice verses necessity?

I, for one will never go back to hardtails.

Is FS for everyone? If you are traveling less than 15 mph... maybe it's not worth the additional expense; I can understand budgetary reasons. Maybe the skill level of the rider does not require it. Rhetorically, if it were offered at a reasonable price, made affordable to all but the most elementary of users, why would we opt out?

Riddle this: What licensed type of vehicle does not have suspension all around?

Now that I can afford it, I can't see being without.
My spine thanks me. My spine thanks you for listening.
Here's to a healthy spine and unjangled internal organs! KF

 

[Chalo]

We're electrified rides that should - given our speed - have the best machine possible to maintain control.

Unlicensed e-bikes in the USA are usually limited to 20mph. This is a normal cycling speed that nobody finds "crippling". Downhill, we reach 30mph easily and 40mph often enough. I have never heard a cyclist say, "I'm not going to ride downhill that fast anymore, it beats me up too bad". These are streets and roads we're talking about, not icefalls and rock gardens.

Hardtails do not give control; they beat you to death in a most unforgiving way.

Many years ago I owned a customized Honda Odyssey: Imagine a 4W ATV with front suspension like a VW, solid rear axle, balloon tires all around, and a full roll cage. After two years I sold it off because I was getting beat to death,

You were riding this thing to work, to the grocery store, or on long country road rides? If not, why is this relevant?

We don't drive cars without suspension; I don't even know if you can find one.

We don't move at car speeds either; we go at go-kart speeds. There are lots of go-karts without suspension. Plus, we have the benefits of single track vehicles and much larger diameter wheels, which both improve our ride compared to that of a go-kart. And we can stand up when things get hairy.

Do they make motorcycles without suspension?

The Rokon Ranger has been in production for longer than any other motorcycle I can think of except the Enfield India Bullet and those Russian BMW clones. And unlike most motorcycles, it runs at speeds typical of e-bikes.

Rhetorically, if it were offered at a reasonable price, made affordable to all but the most elementary of users, why would we opt out?

Weight. Loss of frame rigidity. Extra maintenance. Points of failure. Filling limited space that can be used for carrying useful things like batteries, tools, or water. And because no matter the price, it uses up the budget that could instead be devoted to having a nicer bike.

Riddle this: What licensed type of vehicle does not have suspension all around?

Most earth movers don't have mechanical suspension. That's our speed range, too.

 

[cal3thousand]

Go - karts may not have suspension, but only a fool would commute on one. Sure, 15 minutes on a track are OK, but 5 minutes on an LA road and you'll be turning around for home.




Back to the point at hand:

Suspension = gaining comfort for losing some efficiency. Since I have a bit of 'help' on an ebike, I'd give up some of that 'help' for additional comfort. (and some will claim reliability, but really... how much is reliability REALLY affected in everyday use? not enough to matter [to me at least])


How much you should trade is up to your personal comfort / efficiency needs.

Some things to consider: You can have the 'best of both worlds' in some cases. My front forks have a "lock-out" feature that make it VERY similar to a rigid fork when pedal efficiency is the goal. It also has a "blowout" valve that will give you travel if you hit a sufficiently hard impact while in "lockout" mode.

I put the same one on my wife's new bike, but with a handlebar mounted thumbswitch, so she can flip the modes on-the-fly

 

[Chalo]

Suspension = gaining comfort for losing some efficiency. Since I have a bit of 'help' on an ebike, I'd give up some of that 'help' for additional comfort.

You left out purchase cost, weight, maintenance, reliability, frame rigidity, onboard space, weight carrying versatility, drivetrain configuration options... E-power doesn't "help" you will all of these things.

Yes, suspension isn't as much of a compromise for an e-bike as it is for a normal bike, but it really only becomes an obvious best choice if you don't pedal and you go at motor vehicle speeds. In which case, what you have is a motorcycle.

 

[cal3thousand]

Suspension = gaining comfort for losing some efficiency. Since I have a bit of 'help' on an ebike, I'd give up some of that 'help' for additional comfort.

You left out purchase cost, weight, maintenance, reliability (no I didn't), frame rigidity, onboard space, weight carrying versatility, drivetrain configuration options... E-power doesn't "help" you will all of these things.

Yes, suspension isn't as much of a compromise for an e-bike as it is for a normal bike, but it really only becomes an obvious best choice if you don't pedal and you go at motor vehicle speeds. In which case, what you have is a motorcycle.

Cost... if you can't pay, don't play.

weight... e-bike makes the difference in weight negligible. If not, you don't have an ebike, you have a bike with some batteries.

maintenance... pfft. Ok. the increased maintenance is laughable. You're reaching here.

reliability...I already addressed the real world validity of this claim. If your suspension makes the bike less reliable, you're doing it wrong.

rigidity... You may have a point (small), but we are not talking drifting/racing 4 wheeled structures where rigidity has a huge effect. For most e-bikers the effect doesn't come into play unless biking at the limits of grip. And biking at those speeds, some would argue that suspension will actually help your handling (especially on a rough surface) to the point that the modicum of rigidity lost is a fair price to pay.

on-board space: Only an issue if we are talking about going full squish. FS bikes don't suffer this. And this is where creativity and craft skill goes a long way.

weight carrying versatility, drivetrain configuration options: These are all things that affect various bike form factors in one way or another. If these things were our main objectives, we would not be doing e-bikes. We would be doing electric cars and the like.

Every choice about an e-bike is a compromise as there is always another option that could have been used. Without getting into labeling the all variants of ebikes (you have to agree there is quite a spread on this forum), it is easy to see that at a certain point, suspension is a logical step for e-biking unless you have other 'requirements' that limit you from enjoying suspension. e.g. rigid bike purist, weight-weeny, crazy cargo hauler or not-so-good-with-maintence-guy, or broke-guy :x

 

[full-throttle]

^^ And this is why I think chalo is simply a troll and has lost any respect from many people here - every time is cornered in his flawed argument he changes the subject

We are not discussing go-karts, earth-moving machinery, track bikes, free-style BMX, road bikes with no 10kg of motor and battery.. shopping trolleys..
It's a poll on suspension on e-bikes
The majority of those who bothered to vote agree that is essential, so suck it

 

[Kingfish]

^^ And this is why I think chalo is simply a troll and has lost any respect from many people here - every time is cornered in his flawed argument he changes the subject

We are not discussing go-karts, earth-moving machinery, track bikes, free-style BMX, road bikes with no 10kg of motor and battery.. shopping trolleys..
It's a poll on suspension on e-bikes
The majority of those who bothered to vote agree that is essential, so suck it

^+1 Have to second that entire thought. Disappointed in the rebuttal.

Although I will take this moment to add that there isn't a hardtail made on this planet that could have saved me from the sudden nasty poorly engineered and positioned road drainage spanning the bike margins like little drop-bombs on the windy road leading down from Rattlesnake Lake weekend before last; here I yam barreling down the hill at 40+mph when I hit the 4 or 5" drop onto the 2x2 ft square drain and bounced out: Front suspension bottomed, large phatty tires got me over the hump and when the rear hit - I popped out like I was riding a bronking buck, hung on for... (I was gonna to say "for dear life" but it woz actually pretty fun) as my arse flew outta the seat then back down again - didn't hardly pause; more throttle. Prolly scared the bejesus out of the drivers behind me
(and there were more drop-bombs like that although managed to avoid the rest)

In that situation - a hardtail would just plain break or taco & then face plant raspberry. Unless that is you ride legal :?

I like to ride fast and hard. Been riding like that since I was a squirt, only I seem to go faster as I get older. Life is short. So am I. Should have been a jockey. :lol:

Short story: Suspension lets me travel the way I want.

Going for it, and loving it! KF

 

[Chalo]

You're the one who brought up cars, dune buggies, whatever-- and then challenged me for examples of unsuspended vehicles. I provide examples, and I'm changing the subject?

Riding in the gutter at 40+ mph is your choice, and it's a dumb one. If suspension is the right tool for making dumb choices, so be it. I'm just saying there are other feasible, non-fetishistic options that may make more sense when motor power is limited by nature or by intention.

"More is better" is a road that leads to using a jacked-up 4x4 pickup truck on mud tires to go to the corner store. There is no need or reward for dragging a bicycle down that road.

 

[cal3thousand]

You're the one who brought up cars, dune buggies, whatever-- and then challenged me for examples of unsuspended vehicles. I provide examples, and I'm changing the subject?

Riding in the gutter at 40+ mph is your choice, and it's a dumb one. If suspension is the right tool for making dumb choices, so be it. I'm just saying there are other feasible, non-fetishistic options that may make more sense when motor power is limited by nature or by intention.

"More is better" is a road that leads to using a jacked-up 4x4 pickup truck on mud tires to go to the corner store. There is no need or reward for dragging a bicycle down that road.

No, it's that your examples lean towards hyperbole by fixing on the far end of the spectrum. And then saying that "suspension" is leading down a road that bikes shouldn't go by trying to classify e-bikes according to an old paradigm.

If you don't want to go there, fine. But there's nothing dumb about it unless you're clueless to the benefits and/or averse to the work required.

Fetishistic? I'm sure I'm not the only one that thinks your obsession with styfling progession in the name of simplicity is a bit along those lines. You stick to your 20 mph rigid road-legal "smart" riding ways and the rest of us will be "dumb" blowing by you at 40mph (gutter, sidewalk, street, grass, rocky loose gravel, tarmac, whatever) in comfort.

 

[Kingfish]

Chalo, it wasn't a gutter: The rural road to the Lake is steep, twisty, and newly paved + the goofy service people did not relevel or bevel or raise the drainage covers that are in the bike margins. Google viewer will show it pretty well. It's a lousy place to put drainage in the roadway where bikes travel where anymore towards the right is a nasty ditch or mountain side.

There are also paved bike trails in my region that have roots breaking through and creating hazards for hardtails. I don't care much for it on a FS bike either though it helps.

I fear Chalo that you have not applied yourself to any long-distance type of riding, or perhaps technical riding. Austin was the town that convinced me after my first time around Town Lake to bag the roadie and get myself into Mtn bikes w/ front suspension (the source for my P0 ebike). It's difficult for me to believe you could live there and ride the rural trails w/o any sort of suspension. Please tell me you didn't deny yourself one of the very best urban mtn bike experiences on the planet?!?

Remotely, KF
edit: corrected misspellng; my bad

 

[spinningmagnets]

The question of whether or not to advise someone to use suspension (none, hardtail + front suspension fork [+thudbuster?], or full-suspension) is a complex question, and I feel it is more dependent on the application...

Dogman just recently posted a slow-winding 9C 2812 @48V, it has great climbing ability, but it only has a top-speed of 19-MPH on flat terrain. Even then he used an FS frame (has mentioned back issues like me). Slow enough top-speed that a solid fork is not a disaster if using fat tires?

As far as a front suspension fork, the traditional leaned-forward posture puts a lot of weight on the riders wrists, so in the event of a sudden and unexpected pothole, a non-suspension fork can hurt quite a bit...especially if you are older (like me). On a recumbent, rear suspension has the greater effect, and front suspension is less of an issue. Although, a bump on a downhill curve can cause a short "loss of control" while the front wheel is in the air. Clearly worse at high speed, but possibly of concern...even at lower speeds?

For an upright posture (like my recommended semi-recumbent), a hardtail can really hurt someones back when you are forced to suddenly hit a pothole (cars with texting-teen drivers are sometimes rude, don't you agree?).

I recall reading that in the early days of motorcycle racing, the extra weight of suspension was pondered at length by many engineers and riders. The comfort of the rider was of no concern to anyone involved. The final decision was that the few who risked the extra weight had an advantage when the motorcycle hit irregularities on the track. Bone-shakers sometimes lost control, while suspension bikes kept their tires in contact with the track more often and for longer times.

My most spectacular wipeout was on a non-motored bicycle at modest speeds. Some builders here have road-bikes with a light mild-assist E-system for hills, others have crotch rockets, so...

 

[Chalo]

Fetishistic?

Yep. It's moto-fetishism-- the displaced worship of certain motor vehicles and the mistaken assumption that what works best for them works best for everything. That's why many here prefer bad disc brakes to good rim brakes, bad suspension to good tires on a rigid bike, DOT tires to fast tires, bodywork, "tanks", super bright off-road racer type lighting, etc. It's all just a more elaborate and expensive expression of putting playing cards in the spokes to make a motor sound.

You stick to your 20 mph rigid road-legal "smart" riding ways and the rest of us will be "dumb" blowing by you at 40mph (gutter, sidewalk, street, grass, rocky loose gravel, tarmac, whatever) in comfort.

And someone on a loud Harley will blow by you, proving... nothing. Just as you prove nothing by going faster than pedal speed on an improvised illegal e-motorcycle poorly disguised as a bicycle.

 

[full-throttle]

mistaken assumption that what works best for them works best for everything

This is exactly what you do all the time
#hypocrite

 

[Chalo]

Chilo, it wasn't a gutter: The rural road to the Lake is steep, twisty, and newly paved + the goofy service people did not relevel or bevel or raise the drainage covers that are in the bike margins.

I hate that. Here, I often encounter utility covers sunken down into later applied pavement, in the bike lane. Since the margins of the road are also the most tree-shaded part, it's easy to get caught by surprise in dusky or dark conditions. Having a suspension fork didn't make me hate those things less, but it probably did make them sting less. It's hard to say how well the softer fat tire would do, compared to the fork. Certainly encountering one of those holes on a road bike is no fun.

In Central Texas, flash floods dictate much of the road infrastructure, and the edges of wide roads often have deep dips towards curbside storm drain inlets. They aren't usually hazardous, but they can be annoying to ride through. Because of drains, covers, debris, glass, visibility, and limits to maneuvering, I prefer to ride in the right wheel track of the right lane. I ride right in the middle if motorists get too sloppy about giving me room when they pass.

 

[Stevil_Knevil]

I voted 'Other', because it really does depend on the rider's performance goals, and -ultimately- the platform.

Chalo, have you gotten to ride one of the Surly Trolls yet?

:wink: :lol:

 

[Chalo]

Chalo, have you gotten to ride one of the Surly Trolls yet?

:wink: :lol:

I bought a Surly 1x1 back in 2000. I have considered getting an Ogre since they are available in 24" frame size. I have a Krampus fork on my custom Bohemian semi-fatbike.

They are good bikes, no nonsense. They sell themselves on their merits. No marketing hype, constant gratuitous updating, or moto-fetishism required to make them succeed. Wink lol indeed.