Re: Chain idler efficiency - roller vs. toothed

Tom Sherman

TandemFan wrote:

[cross-posted to ARBR for Perry Butler's amusement]

> We have a R[ANS] Screamer tandem and there are a few idler rollers for
> the chain. An outfit sells toothed idlers for about $250:
> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>
> They have a long blurb on why they are better:
>
> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>
> What's the scoop? Does it make any difference at all, or are we going
> to go faster?
>
Someone needs to tell Pat Franz that it is "RANS" and not "Rans".

While the manufacturers in question are trying to meet a price point for
their bicycles, they are not going to be putting junk chain idlers on
their bicycles [1]. Therefore, while there is room for improvement, the
gains will likely be small as drive-train friction is a small component
of total non-conservative losses, even on a recumbent with a complicated
chain-line.

If you want to make a RANS Screamer a lot faster than stock, put a front
fairing (Zzipper or Mueller) and a bodysock on the bike.

[1] Unlike some defunct manufacturers of the past.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Jon Bendtsen

Tom Sherman wrote:
> TandemFan wrote:
>
> [cross-posted to ARBR for Perry Butler's amusement]
>
>> We have a R[ANS] Screamer tandem and there are a few idler rollers for
>> the chain. An outfit sells toothed idlers for about $250:
>> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>>
>>
>> They have a long blurb on why they are better:
>>
>> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>>
>>
>> What's the scoop? Does it make any difference at all, or are we going
>> to go faster?
>>
> Someone needs to tell Pat Franz that it is "RANS" and not "Rans".
>
> While the manufacturers in question are trying to meet a price point for
> their bicycles, they are not going to be putting junk chain idlers on
> their bicycles [1]. Therefore, while there is room for improvement, the
> gains will likely be small as drive-train friction is a small component
> of total non-conservative losses, even on a recumbent with a complicated
> chain-line.

Why not avoid idlers and recumbents with complicated chain-lines?

It might not (yet) be possible with a tandem, but for a single
rider bike, cruzbike offers a short normal chain-line.


JonB

Tom Sherman

Jon Bendtsen wrote:
> Tom Sherman wrote:
>> TandemFan wrote:
>>
>> [cross-posted to ARBR for Perry Butler's amusement]
>>
>>> We have a R[ANS] Screamer tandem and there are a few idler rollers for
>>> the chain. An outfit sells toothed idlers for about $250:
>>> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>>>
>>>
>>> They have a long blurb on why they are better:
>>>
>>> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>>>
>>>
>>> What's the scoop? Does it make any difference at all, or are we going
>>> to go faster?
>>>
>> Someone needs to tell Pat Franz that it is "RANS" and not "Rans".
>>
>> While the manufacturers in question are trying to meet a price point
>> for their bicycles, they are not going to be putting junk chain idlers
>> on their bicycles [1]. Therefore, while there is room for improvement,
>> the gains will likely be small as drive-train friction is a small
>> component of total non-conservative losses, even on a recumbent with a
>> complicated chain-line.
>
> Why not avoid idlers and recumbents with complicated chain-lines?
>
> It might not (yet) be possible with a tandem, but for a single
> rider bike, cruzbike offers a short normal chain-line.
>
And introduces a whole other set of compromises in seating position,
weight distribution, traction on steep hills, etc. Long chain lines are
not necessarily a bad thing, as several issues with short chain lines go
away that make wide range gearing difficult.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Jon Bendtsen

Tom Sherman wrote:
> Jon Bendtsen wrote:
>> Tom Sherman wrote:
>>> TandemFan wrote:
>>>
>>> [cross-posted to ARBR for Perry Butler's amusement]
>>>
>>>> We have a R[ANS] Screamer tandem and there are a few idler rollers for
>>>> the chain. An outfit sells toothed idlers for about $250:
>>>> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>>>>
>>>>
>>>> They have a long blurb on why they are better:
>>>>
>>>> http://www.terracycle.com/Merchant2..._Code=IdlersALL
>>>>
>>>>
>>>> What's the scoop? Does it make any difference at all, or are we going
>>>> to go faster?
>>>>
>>> Someone needs to tell Pat Franz that it is "RANS" and not "Rans".
>>>
>>> While the manufacturers in question are trying to meet a price point
>>> for their bicycles, they are not going to be putting junk chain
>>> idlers on their bicycles [1]. Therefore, while there is room for
>>> improvement, the gains will likely be small as drive-train friction
>>> is a small component of total non-conservative losses, even on a
>>> recumbent with a complicated chain-line.
>>
>> Why not avoid idlers and recumbents with complicated chain-lines?
>>
>> It might not (yet) be possible with a tandem, but for a single
>> rider bike, cruzbike offers a short normal chain-line.
>>
> And introduces a whole other set of compromises in seating position,

yeah, thats true.


> weight distribution, traction on steep hills, etc. Long chain lines are

actually i dont find the traction too bad up hill. But
we dont really have hills in Denmark, it's just flat flat
flat compared to other places.


> not necessarily a bad thing, as several issues with short chain lines go
> away that make wide range gearing difficult.

Why would short chainlines make wide range gearing difficult?

Adam Kadlubek

On 28 Kwi, 00:37, Jon Bendtsen <no...@example.com> wrote:
> Tom Sherman wrote:
> > Jon Bendtsen wrote:
> >> Tom Sherman wrote:
> >>> TandemFan wrote:
>
> >>> [cross-posted to ARBR for Perry Butler's amusement]
>
> >>>> We have a R[ANS] Screamer tandem and there are a few idler rollers for
> >>>> the chain. An outfit sells toothed idlers for about $250:
> >>>>http://www.terracycle.com/Merchant2...n=PROD&Store_Co...
>
> >>>> They have a long blurb on why they are better:
>
> >>>>http://www.terracycle.com/Merchant2...n=CTGY&Store_Co...
>
> >>>> What's the scoop? Does it make any difference at all, or are we going
> >>>> to go faster?
>
> >>> Someone needs to tell Pat Franz that it is "RANS" and not "Rans".
>
> >>> While the manufacturers in question are trying to meet a price point
> >>> for their bicycles, they are not going to be putting junk chain
> >>> idlers on their bicycles [1]. Therefore, while there is room for
> >>> improvement, the gains will likely be small as drive-train friction
> >>> is a small component of total non-conservative losses, even on a
> >>> recumbent with a complicated chain-line.
>
> >> Why not avoid idlers and recumbents with complicated chain-lines?
>
> >> It might not (yet) be possible with a tandem, but for a single
> >> rider bike, cruzbike offers a short normal chain-line.
>
> > And introduces a whole other set of compromises in seating position,
>
> yeah, thats true.
>
> > weight distribution, traction on steep hills, etc. Long chain lines are
>
> actually i dont find the traction too bad up hill. But
> we dont really have hills in Denmark, it's just flat flat
> flat compared to other places.
>
> > not necessarily a bad thing, as several issues with short chain lines go
> > away that make wide range gearing difficult.
>
> Why would short chainlines make wide range gearing difficult?

Cross chain without guilt for instance.

--
Adam Kadlubek

Jon Bendtsen

Adam Kadlubek wrote:
> On 28 Kwi, 00:37, Jon Bendtsen <no...@example.com> wrote:
>> Tom Sherman wrote:
>>> Jon Bendtsen wrote:
>>>> Tom Sherman wrote:
>>>>> TandemFan wrote:
>>>>> [cross-posted to ARBR for Perry Butler's amusement]
>>>>>> We have a R[ANS] Screamer tandem and there are a few idler rollers for
>>>>>> the chain. An outfit sells toothed idlers for about $250:
>>>>>> http://www.terracycle.com/Merchant2...n=PROD&Store_Co...
>>>>>> They have a long blurb on why they are better:
>>>>>> http://www.terracycle.com/Merchant2...n=CTGY&Store_Co...
>>>>>> What's the scoop? Does it make any difference at all, or are we going
>>>>>> to go faster?
>>>>> Someone needs to tell Pat Franz that it is "RANS" and not "Rans".
>>>>> While the manufacturers in question are trying to meet a price point
>>>>> for their bicycles, they are not going to be putting junk chain
>>>>> idlers on their bicycles [1]. Therefore, while there is room for
>>>>> improvement, the gains will likely be small as drive-train friction
>>>>> is a small component of total non-conservative losses, even on a
>>>>> recumbent with a complicated chain-line.
>>>> Why not avoid idlers and recumbents with complicated chain-lines?
>>>> It might not (yet) be possible with a tandem, but for a single
>>>> rider bike, cruzbike offers a short normal chain-line.
>>> And introduces a whole other set of compromises in seating position,
>> yeah, thats true.
>>
>>> weight distribution, traction on steep hills, etc. Long chain lines are
>> actually i dont find the traction too bad up hill. But
>> we dont really have hills in Denmark, it's just flat flat
>> flat compared to other places.
>>
>>> not necessarily a bad thing, as several issues with short chain lines go
>>> away that make wide range gearing difficult.
>> Why would short chainlines make wide range gearing difficult?
>
> Cross chain without guilt for instance.

Then combine a rohloff/nuvinci + a schlumpf drive == 0 cross chain.
If normal bikes can live with some cross chain, so can a recumbent.



JonB

Tom Sherman

Jon Bendtsen wrote:
> Tom Sherman wrote:
>> [...]
>> not necessarily a bad thing, as several issues with short chain lines
>> go away that make wide range gearing difficult.
>
> Why would short chainlines make wide range gearing difficult?

Proper alignment between front chain wheels and rear sprockets becomes
more critical with a shorter chain line, which makes things more
difficult when using non-standard components.

A long chain line in combination with a idler tensioner (e.g. Easy
Racers) or a mid-drive can allow for chain wheel and sprocket
combinations that would not work on a short chain line unless custom
derailers (sic) were used.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Tom Sherman

Jon Bendtsen wrote:
> Adam Kadlubek wrote:
>> On 28 Kwi, 00:37, Jon Bendtsen <no...@example.com> wrote:
>>> Tom Sherman wrote:
>>>> Jon Bendtsen wrote:
>>>>> Tom Sherman wrote:
>>>>>> TandemFan wrote:
>>>>>> [cross-posted to ARBR for Perry Butler's amusement]
>>>>>>> We have a R[ANS] Screamer tandem and there are a few idler
>>>>>>> rollers for
>>>>>>> the chain. An outfit sells toothed idlers for about $250:
>>>>>>> http://www.terracycle.com/Merchant2...n=PROD&Store_Co...
>>>>>>>
>>>>>>> They have a long blurb on why they are better:
>>>>>>> http://www.terracycle.com/Merchant2...n=CTGY&Store_Co...
>>>>>>>
>>>>>>> What's the scoop? Does it make any difference at all, or are we
>>>>>>> going
>>>>>>> to go faster?
>>>>>> Someone needs to tell Pat Franz that it is "RANS" and not "Rans".
>>>>>> While the manufacturers in question are trying to meet a price point
>>>>>> for their bicycles, they are not going to be putting junk chain
>>>>>> idlers on their bicycles [1]. Therefore, while there is room for
>>>>>> improvement, the gains will likely be small as drive-train friction
>>>>>> is a small component of total non-conservative losses, even on a
>>>>>> recumbent with a complicated chain-line.
>>>>> Why not avoid idlers and recumbents with complicated chain-lines?
>>>>> It might not (yet) be possible with a tandem, but for a single
>>>>> rider bike, cruzbike offers a short normal chain-line.
>>>> And introduces a whole other set of compromises in seating position,
>>> yeah, thats true.
>>>
>>>> weight distribution, traction on steep hills, etc. Long chain lines are
>>> actually i dont find the traction too bad up hill. But
>>> we dont really have hills in Denmark, it's just flat flat
>>> flat compared to other places.
>>>
>>>> not necessarily a bad thing, as several issues with short chain
>>>> lines go
>>>> away that make wide range gearing difficult.
>>> Why would short chainlines make wide range gearing difficult?
>>
>> Cross chain without guilt for instance.
>
> Then combine a rohloff/nuvinci + a schlumpf drive == 0 cross chain.

No cross chain, but large expense.

> If normal bikes can live with some cross chain, so can a recumbent.
>
Cross-chaining becomes much less of an detriment with a long chain line.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

jobst.brandt@stanfordalumni.org

The angle at which the chain enters and leaves front sprockets and
derailleur idlers is the sine of the angle which is the lateral offset
between the two ends of the chain span divided by the free span
length. Therefore, the longer the chainstays and the fewer the gears
on the sprocket cluster, the smaller the angle between chain and
sprocket plane. The angle causes lateral sprocket tooth wear and
idler wheel wear.

Jobst Brandt

Tom Sherman

jobst.brandt@stanfordalumni.org aka Jobst Brandt wrote:
> The angle at which the chain enters and leaves front sprockets and
> derailleur idlers is the sine of the angle which is the lateral offset
> between the two ends of the chain span divided by the free span
> length. Therefore, the longer the chainstays and the fewer the gears
> on the sprocket cluster, the smaller the angle between chain and
> sprocket plane. The angle causes lateral sprocket tooth wear and
> idler wheel wear.
>
Indeed, which is why I would not deliberately ride in cross chain gears
on my ATB with its 43 cm chain line (BB to hub) but will do so on my
RANS Rocket with its 131 cm chain line.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

Jon Bendtsen

Tom Sherman wrote:
> Jon Bendtsen wrote:
>> Adam Kadlubek wrote:
>>> On 28 Kwi, 00:37, Jon Bendtsen <no...@example.com> wrote:
>>>> Tom Sherman wrote:
>>>>> Jon Bendtsen wrote:
>>>>>> Tom Sherman wrote:
>>>>>>> TandemFan wrote:
>>>>>>> [cross-posted to ARBR for Perry Butler's amusement]

[cuuuut]

>>>>> not necessarily a bad thing, as several issues with short chain
>>>>> lines go
>>>>> away that make wide range gearing difficult.
>>>> Why would short chainlines make wide range gearing difficult?
>>>
>>> Cross chain without guilt for instance.
>>
>> Then combine a rohloff/nuvinci + a schlumpf drive == 0 cross chain.
>
> No cross chain, but large expense.

Yeah, rohloff is expensive. Nuvinci is not so bad, neither are the
schlumpf drive. Together they are, but you do get a VERY wide gear
range with no steps, it is all continuously variable. I dont think
i need more range than what the Nuvinci can give me, which is a little
wider than the 8 gear derailure i have now.


>> If normal bikes can live with some cross chain, so can a recumbent.
>>
> Cross-chaining becomes much less of an detriment with a long chain line.

You get other problems with a long chainline. If something hits it
trash or some plants.

But as you said above, it's a question about tradeoffs. I just dont
like long chainlines. And neither those tubes they run in.

Jon Bendtsen

Jon Bendtsen wrote:
> Tom Sherman wrote:
>> Jon Bendtsen wrote:
>>> Adam Kadlubek wrote:
>>>> On 28 Kwi, 00:37, Jon Bendtsen <no...@example.com> wrote:
>>>>> Tom Sherman wrote:
>>>>>> Jon Bendtsen wrote:
>>>>>>> Tom Sherman wrote:
>>>>>>>> TandemFan wrote:
>>>>>>>> [cross-posted to ARBR for Perry Butler's amusement]
>
> [cuuuut]
>
>>>>>> not necessarily a bad thing, as several issues with short chain
>>>>>> lines go
>>>>>> away that make wide range gearing difficult.
>>>>> Why would short chainlines make wide range gearing difficult?
>>>>
>>>> Cross chain without guilt for instance.
>>>
>>> Then combine a rohloff/nuvinci + a schlumpf drive == 0 cross chain.
>>
>> No cross chain, but large expense.
>
> Yeah, rohloff is expensive. Nuvinci is not so bad, neither are the
> schlumpf drive. Together they are, but you do get a VERY wide gear
> range with no steps, it is all continuously variable. I dont think
> i need more range than what the Nuvinci can give me, which is a little
> wider than the 8 gear derailure i have now.

i forgot to mention that i eventually want a Nuvinci, so i
might as well go for a bike that has a short chain line +
you can actually mount a child seat, i havent found others
that allowed that.



JonB