[Bicyclist]

Without starting a sh!t storm about whether or not single pivot is "better" than any other design, I have a question.

Is it true that with a certain chainring that is "inline" with the pivot, a single pivot bike will not have pedal feedback? I've noticed when riding a SP with multiple rings, they will have feedback in certain rings and not others. Is there are reason for that or not?

If that is the case, is there a way to determine what size ring would negate the effects of pedal feedback?

Like I said no arguing, I just want to know the answer to that question.

EDIT: This is assuming no idler.

 

[iridebikes]

I believe that chainring size does have some say in how well a single pivot bike pedals, but it's moreso the location of the pivot itself. I believe that if the pivot is inline with your chain it will pedal better than if you have the pivot way below your chain, but the location of the pivot also plays a huge roll in how active your suspension is.

 

[Bicyclist]

OK, so to a point it affects it?

 

[TheMontashu]

I think it has more to do with size of the ring, the closer the chain is in height to the pivot is what effects. I am not sure how to explain it but I think the bigger the ring the better it pedals, this has something to do with the chain being close to the pivot haivng less pedal feedback.

 

[Bicyclist]

But what about being a really low pivot? Then wouldn't a smaller ring be better for pedalling?

 

[kidwoo]

But what about being a really low pivot? Then wouldn't a smaller ring be better for pedalling?

usually

It's not only single pivots though. There are plenty of multipivot bikes that pedal like ass outside of a specific range of gearing too.

 

[Bicyclist]

Yeah, I've noticed. My bud's 7point even has a bit of feedback in the granny.

 

[no skid marks]

*edit,I removed a bit hereas it was taken wrong way*
If the chain is pulling dirrectly to the pivot(forget about cassette size on the rear for now)then it won't affect the suspension. If it's above the pivot it will try and pull the rear wheel up,if it's below the pivot it will try to pull it down. Step back and have a look at a single pivot bike and figure it out,it aint rocket science.
I'm not saying this is a good suspension design just explaining it. Single pivots are **** unless the pivot is at least as high as the rear axle when bottomed out. Yes with a idler or BMW/Lahar set up.

 

[kidwoo]

Yeah, I've noticed. My bud's 7point even has a bit of feedback in the granny.

You're not allowed to say that on this site.

 

[Bicyclist]

Oh for crying out loud. If the chain is pulling dirrectly to the pivot(forget about cassette size on the rear for now)then it won't affect the suspension. If it's above the pivot it will try and pull the rear wheel up,if it's below the pivot it will try to pull it down. Step back and have a look at a single pivot bike and figure it out,it aint rocket science.
I'm not saying this is a good suspension design just explaining it. Single pivots are **** unless the pivot is at least as high as the rear axle when bottomed out. Yes with a idler or BMW/Lahar set up.

I'm having trouble visualizing it so I asked. Geez. I guess learning is dumb.

I just can't see how it will "pull" the wheel. I can see there being resistance provided by the chain, but it's not "pulling" the wheel, it's trying to restrict its movement.

 

[Bicyclist]

You're not allowed to say that on this site.

Now I'm just counting time till my hit comes.

 

[no skid marks]

Okay your shoulder is the pivot,You've loosened your belt and stuck your arm in it by your side,your hand is say 10 inches away from your hip. If you tighten the belt(chain) it will pull your hand(rear wheel) in. Yes the belt is a loop but forget that,it's still the same as a chain pulling.
It's a battle of power,on a high pivot with you pedalling really hard,the chain tension of you pedalling will over power small hits on the suspension that have less force,therfore locking out the suspension for small hits. A big hit though with more force will over power the chain and will pull the cranks backward and over power your pedalling force.

 

[kidwoo]

Single pivots are **** unless the pivot is at least as high as the rear axle when bottomed out.

You just called a whole host of very well riding bikes a bunch of aterisks.



Think about it real hard before you respond.

 

[Bicyclist]

Okay your shoulder is the pivot,You've loosened your belt and stuck your arm in it by your side,your hand is say 10 inches away from your hip. If you tighten the belt(chain) it will pull your hand(rear wheel) in. Yes the belt is a loop but forget that,it's still the same as a chain pulling.

Makes sense.

Woo, he must be referring to how the axle path curves inwards at the end on a lower pivot bike. I don't think it makes the bike **** either but it's a preference thing.

 

[no skid marks]

Makes sense.

Woo, he must be referring to how the axle path curves inwards at the end on a lower pivot bike. I don't think it makes the bike **** either but it's a preference thing.

Low pivot bikes bounce over most small obstacles.The suspension may work over larger obstacles but not efficiently. Off drops,sure it'll work as good as anything when the force is just downward. If you ride into something with the back wheel,say a gutter,then the hit is pushing the wheel backwards not up so the bike wants to just bounce over it as the swingarm dosn't have much actuation as it's just being pulled back along it's length. With a high pivot the wheel will travel with the impact therfore activating the suspension. Most of the hits on a MTB are square adge hits so it makes sense to have a rearward axle path. Also the rear will travel on a similer line to the front wheel travel,so the wheelbase will be more consistent or extend the further into the travel it gets.Sketchy situations like bottoming out you're better with a longer more stable wheelbase.
Orange 222 worked great in the hands of a strong skilled rider like Peaty,it's a hardtail most of the time accept the bigger hits,it's light,and it peddals great as the suspension gets locked out to an extent.But it's more his skills that won,yes the bike feels fast but for most of us it's lack of suspension performance would hinder us in I recon.

 

[dhkid]

with out getting too technical, it depends on two things. pivot location and chain ring size.

like you said, with a low pivot, the axel path would be close to that of a consentric pivot, ie, no chain growth at all. so chain ring size doesn't effect it too much.

then there is the high pivot, where i would have to disagree with no skid marks a bit. hopefully it doesn't start a big argument. it isn't as simple as as long as you chain lines up with your pivot, because there will still me a small moment about the axel from the cassette.

but for simplicity sake, having your chain line up with your pivot would have the least pedal feedback for a high single pivot.

you can easily draw out a simple free body diagram, draw a straight line from your axel to pivot, making up your rear 'swing arm'. and another line for the chain, if its parallel to the 'swing arm' as it moves through its travel, there will be no pedal feedback or chain growth at all. so the closer the two lines are to being parallel the better, if thats what you want.

on a side note, having a bit of pedal feedback may be desirable. having it makes the rear wheel dig in acccelerate a bit better.

peace.
adam.

 

[thaflyinfatman]

Unfortunately pretty well all the above responses are incorrect to at least some degree. What determines chain extension is effectively the axle path relative to the chain line. If they are dead perpendicular, then there will be no chain extension. If the axle path has a component of movement (as in a vector component, if you're not familiar with this then look it up because it's very useful stuff) that is parallel to the chain line then it will have some degree of feedback (which also means that the chain force alone will have some influence on the suspension - ignoring other influences on the suspension at the moment, most of all the weight shifts and tyre traction forces). Obviously the chainline changes in different chainrings, tending to lean "downwards" at the front for smaller chainrings, which is why pedal feedback is usually higher in smaller chainrings.

Hope this helps. If you need a diagram, just ask.

Edit: by the way, the inference here is that you can have chain extension/feedback even with a concentric-pivot design (including concentric rollers on some high pivot bikes). Whether or not it's significant or perceptible is another argument altogether.

 

[dw]

Is it true that with a certain chainring that is "inline" with the pivot, a single pivot bike will not have pedal feedback?

If you are asking the question: "If the pivot on a single pivot bike lies on the chainline then will the bike have no pedal feedback" the answer is no

Dave

 

[Sandwich]

i think fatty pretty much hit the nail on the head....but I wanted to point out that chainring size has nothing to do with it, it's all chainring height.
Chainring below the pivot, pressure on the pedals will pull the rear down, and when hitting a bump it will pull the pedals backwards. The torque applied when sagged (which extends the suspension and lifts the rider up) is what is called, in the old day, biopacing or pogo.

Low pivots do the opposite to a much lesser degree. Pedaling forces pull the rear wheel up, but due to the freewheel you would feel nothing when hitting a bump. Since low pivots are generally much closer to the chainring than a high pivot, these forces tend to be less. Nobody makes a really low pivot (below BB).

I hope that makes sense. That's how I always viewed it. A little chain torque can pull the rear wheel into the ground, which could theoretically help acceleration, and definately help climbing. That's why most high pivot bikes have idlers or jackshafts. People don't like the feeling of chain torque.


DW- Are you sure that's really what you mean? I read that as "A bike with an idler or chainring-line pivot will have pedal feedback." Is that correct? Perhaps in the most minute amounts, but the pedals on my Brooklyn don't move much when it's compressed.

 

[OGRipper]

hitting a bump it will pull the pedals backwards. This is what is called, in the old day, biopacing or pogo.

Just to clarify, feedback from bumps ("pulling the pedals backwards") and "pogo" from pedaling are two different things, even if they are related.

 

[Sandwich]

you are correct, I'll edit that. biopacing is when you pedal and the rear end extends...making the rider go up and down with every pedal stroke...my train of thought was off.

 

[dw]

DW- Are you sure that's really what you mean? I read that as "A bike with an idler or chainring-line pivot will have pedal feedback." Is that correct? Perhaps in the most minute amounts, but the pedals on my Brooklyn don't move much when it's compressed.

If the pivot lies directly on the chainline, (Your Brooklyn does not have this) then you will have some gearing effects giving some amount of pedal feedback at some point in the travel.

I have discussed this in painstaking detail previously, so check out the archives for the math.

Dave

 

[davep]

Oh for crying out loud. .......

Come on.. not everyone here has taken a statics class, or college physics. He is just trying to learn.

 

[dhpunk~]

regards to pivot/chainline......i believe Patrick Morewood had worked on this pedal feedback a few years back. they tried to run the chain up from the ring to a roller directly mounted to the pivot. now speaking from my butt, id assume it either wasnt worth adding another bearing and roller (added weight/another moving part) because of minimal effect......but had the same outcome by lowering th pivot (changed /07) without adding extra junk/weight.

dunno, just a thought!

sweeney

 

[MorewoodKid]

regards to pivot/chainline......i believe Peter Morewood had worked on this pedal feedback a few years back. they tried to run the chain up from the ring to a roller directly mounted to the pivot. now speaking from my butt, id assume it either wasnt worth adding another bearing and roller (added weight/another moving part) because of minimal effect......but had the same outcome by lowering th pivot (changed /07) without adding extra junk/weight.

dunno, just a thought!

sweeney

Peter Morewood?

 

[dhpunk~]

HA....Patrick, was testin ya'll

 

[Kornphlake]

Singlepivots are pretty simple to understand when you don't understand what you're looking at. The real key to understanding pedal feedback is to go and ride a bike, some people are more sensitive to pedal feedback than others, if you don't notice it then it doesn't exist, if you notice it and feel like it's raining on your parade go find a bike that you don't feel pedal feedback on.

 

[dhpunk~]

Singlepivots are pretty simple to understand when you don't understand what you're looking at. The real key to understanding pedal feedback is to go and ride a bike, some people are more sensitive to pedal feedback than others, if you don't notice it then it doesn't exist, if you notice it and feel like it's raining on your parade go find a bike that you don't feel pedal feedback on.

I couldnt agree with you more!!

 

[Bicyclist]

Yeah, the issue for me is finding a bike I can ride. I've ridden a Commencal and an ASX, and both had pretty glaring feedback (the ASX only in the little ring). I'd like to try another Commencal but the one I rode was IMO ridiculous.

 

[kidwoo]

Intenses and iron horses pedal very well

You looking for a dh bike or something more freeride-ish?

 

[Bicyclist]

DH. Sunday, Morewood, Commencal, BCD, etc.

I rode a V10 and was stunned at how well it pedalled, but I don't want a V10/M3 'cause I don't need almost 10" of travel for what I do. And the SOCOM just isn't my bike I think. It looks too tall (although I wouldn't mind trying one).

 

[kidwoo]

Giant glory yo.

I forgot about those. The new treks is really good to. I actually know someone selling one for CHEAP.

I've never ridden a morewood outside of a parking lot but I really dislike the way high foreward pivots ride. If the commencal is in there, how bout a turner or cuervo?

Don't focus on the travel numbers on the v10s (especially the newer ones) or an m3. They don't ride feel like any more travel than most of the other bikes out there. I've got two intense bikes and I'm pretty sure their travel numbers are lower than claimed on those. Not a bad thing but I wouldn't focus on the numbers. Other numbers are more important.

 

[OGRipper]

What makes you say you want a DH bike but one without that much travel?

 

[Bicyclist]

I want DH geo but not more than 8" of travel.

I like balanced travel and I'm pretty small so I don't want something where I'll be fighting to control it. The V10 and Trek are a bit too burly and big for what I'm looking for.

I'd definately consider a DHR, especially because 06s are cheeep used right now. (But then again the new ones look sick too).

The El Cuervo is too ugly. I'm sure it's a nice bike but it's hideous.

I guess if I could borrow a 9+" travel bike for a run I'd think about it. The V10 I rode in a parking lot felt nice but giant.

Glorys all end up heavy.

Another thing w/ Intense is price and alignment rumors.
Plus SC has notoriously bad CS.

I need to ride more stuff but I want an idea of what I would like.

 

[OGRipper]

Hmm, still not sure why you're limiting it to 8" but it's not my bike...If not a DHR, howz 'bout a Demo?

 

[kidwoo]

I need to ride more stuff but I want an idea of what I would like.

No doubt about that.

But remember this......because it's gospel.....seriously........TYPES of travel are WAY more important than volume of travel. I've ridden 7" bikes with falling rate designs that feel like they have more than my DHR. My dhr is so retardedly progressive at the end of its stroke, I probably rarely use more than about 6+ inches of it.

I promise......fixating on the travel number doesn't tell you much. Those session 10s don't feel like a 10" version of an orange for instance.

 

[Bicyclist]

I'm on an 05 Demo 8 right now. I really just want to justify a change.

My plan is to upgrade a bit again for this season, then get a new bike next year. I just am trying to ride every bike I can at races, etc. this year to get an idea of what I want.

 

[Bicyclist]

No doubt about that.

But remember this......because it's gospel.....seriously........TYPES of travel are WAY more important than volume of travel. I've ridden 7" bikes with falling rate designs that feel like they have more than my DHR. My dhr is so retardedly progressive at the end of its stroke, I probably rarely use more than about 6+ inches of it.

I promise......fixating on the travel number doesn't tell you much. Those session 10s don't feel like a 10" version of an orange for instance.

I know what you're saying. An SX Trail feels like it's got a ton of travel too for some reason, etc.

I just need to get out and ride everything possible and make a desicion based on feel.

 

[Zark]

Hmm, still not sure why you're limiting it to 8" but it's not my bike...If not a DHR, howz 'bout a Demo?

He's on a Demo!:biggrin:

Mark, just rock that Demo 'til the wheels fall off. Its a hot bike, it seems to be working great for you. Fight off the "upgreadeitis" bro!

 

[Bicyclist]

Yeah, must......fight.......urge.......

Oh well, I probably don't have the money anyways 'cause Bob has a habit of like never paying me.

It's looking like WIDE bars and a lighter spring for my shock and a fork rebuild are on my priority list for now.