Some good food for a rational discussion.
Belt drives, in the sled world or, now, in the snowbikes...are getting a lot of press.
Lots of folks jumping on the "Belt Drive Bandwagon" in the snow sport world long after the CMXDS was released...from OEM (Polaris) to the aftermarket.
We all seem to be assuming that belt-drives are "better"... but how and why seems to be a discussion that is more akin to a political debate than one of actual application in our machines.
Are belt-drives "better"?
I don't know... yet.
But it sure is a blank canvass in terms of a rational, application based, discussion.
But, like anything else in life... there are pro's and con's to belt-drives... by nature.
For me, IMO, on a snowbike...
Durability of a belt in a belt drive in normal use is not a question for me.... not with the relatively low horsepower of an MX bike.
On a sled... we've seen failures, and aftermarket offerings to help minimize these failures... plus redesigns from the factory and new belt designs....They keep evolving.
Polaris, the only OEM currently offering a belt-drive in their production sleds still uses a chain drive in many of their mountian-sled models. Even though a simple longer belt and tensioner would allow for more tooth engagement and slightly less weight... along with a standardization of parts (economy of scale)... All of their 3" track equipped models and the RMSHA inspired
Durability, or robustness, in the world of snowbikers on the mountain, in terms of impacts, is what will be proven this season in the consumers hands.
When it comes to Snowbikes... What is the width of a beltdrive equipped snowbike kit... as measured from the centerline of the track to the outside of the belt enclosure, and how does that compare to to a chaindrive. Will a belt drive be more susceptible to "hits" on the hill in a snowbike
On the AXYS-mtn sleds, the lower part of the drive hangs down pretty low on the chassis... protruding past the bellypan of the sled more than any previous year... Will this be the "Achilles Heel" of the design? Already, the aftermarket is making products to protect this area. Will this be more susceptible to "hits" on the hill in comparison to a fully shrouded chaindrive??
Also...I've watched the videos and listened to presentations on the topic of belt drives.
The term "efficiency" always seems to come up... I'm very familiar with this presentation in the sled world of the Polaris snowmobiles and their factory equipped sleds with belt drives... but that efficiency discussion never seems to make it into the realm of track dynos or vehicle specific testing.
...YET... but it will, I'M sure of it.
In a lot of literature I've read, including that from Synchronous belt drive mfgs like Gates... they refer to belt drives "approaching" or "equaling" chain drives.
This paper, from Gates, provides a lot of good ammo for discussion.
http://www.gates.com/~/media/files/...transmission/white-papers/roller-chain-wp.pdf
How does the Synchronous belt drive compare to a roller-chain... or a silent/HYVO chain in terms of efficiency?
Another good paper from Gates parts 1-5
http://ww2.gates.com/IF/facts/documents/Gf000198.pdf
http://ww2.gates.com/IF/facts/documents/Gf000199.pdf
http://ww2.gates.com/IF/facts/documents/Gf000200.pdf
http://ww2.gates.com/IF/facts/documents/Gf000201.pdf
http://ww2.gates.com/IF/facts/documents/Gf000202.pdf
I've heard numbers claimed like 5% more efficient, 30% more efficient, 50% more efficient.
If this efficiency does make a noticeable difference in a snowbike/sled what characteristics will be noted by the rider in a positive way and are those offset by other factors?
Does a synchronous belt drive get more power to the track than a chain-drive... in a Snowbike (or a sled) application?
Will characters that are "con's" for chains come into play with the drive speeds we are talking about (FPM)... and for what kind of chain, silent, HYVO, roller?
Does a Belt drive require a larger diameter top and bottom pulley to do the same work and not strip teeth (tooth engagement on the pulley)?
Weight is a big deal these days... Polaris used the QuickDrive™ to get the PRO's to really low production weight... but they don't use this drive system across the board... In fact they only use them on the Mountain sleds, and only certain models... the higher loaded 3" track option uses a chaindrive as do the RMSHA race inspired Assaults and the SKS... the chaindrive is more robust... but slightly heavier with chain, sprocket, cover and oil weight.
The aftermarket belt-drive systems are not as light as the OEM QuickDrive™ as they add weight with a tensioner and longer belt with denser pitch.
On a TS snowbike, a roller chain is used... and it does not require an oil bath..but does require some lubrication/tension periodic maintenance.
On sleds, proponents of belt-drives claim that the belt drive will suffer less damage from a broken belt than a chaindrive from a broken chain... and therefore not leave you stranded on the hill.
This, IMO, IS absolutely true...but, I've rarely even heard of a chain breaking that was properly maintained.... so that point would be better made in the statement that a belt drive will not require as much maintenance...even though that maintenance is low.
I have seen broken chains and the sometimes broken case that can accompany it... but not one of those that I've personally viewed was due to anything but lack of maint (old chain, wrong length chain, never adjusted, never changed dirty/wet oil, no oil, improper oil, leaking seal, too small of top sprocket, etc).. easily avoided. So, for me.... this is not an issue with proper maint.
Another topic of discussion is "Rotating mass"... which can be broken down into two categories... Gyroscopic effect... and Inertial effect.
What are the actual numbers relating to this? How does it affect our riding?
I've heard things like "1 lb of rotating mass equals X lbs of...."
Good for boasting, but that does not take into account the overall mass of a rotating assembly (eg driveshaft and sproket)... or the distance from the center of the rotating assembly...eg, 1lb with a diameter of 5X will have more Gyroscopic and inertial affect than the same weight at 1x diameter... this should be taken into consideration to form a more accurate evaluation of a system, IMO, rather than blanket "general" statements.
Weight, robustness, efficiency, cost, maintenance and integration into the vehicle are all things to consider.
All good topics of discussion.
Have at it
AND PLEASE... Keep it rational and factual and application based (snow powersports) .
If you make a claim that one was better than the other in direct comparison...we're all factors the same? (same exact gear ratio, clutching, fuel, state of tune, or any other mods made at the same time).
.
Belt drives, in the sled world or, now, in the snowbikes...are getting a lot of press.
Lots of folks jumping on the "Belt Drive Bandwagon" in the snow sport world long after the CMXDS was released...from OEM (Polaris) to the aftermarket.
We all seem to be assuming that belt-drives are "better"... but how and why seems to be a discussion that is more akin to a political debate than one of actual application in our machines.
Are belt-drives "better"?
I don't know... yet.
But it sure is a blank canvass in terms of a rational, application based, discussion.
But, like anything else in life... there are pro's and con's to belt-drives... by nature.
For me, IMO, on a snowbike...
Durability of a belt in a belt drive in normal use is not a question for me.... not with the relatively low horsepower of an MX bike.
On a sled... we've seen failures, and aftermarket offerings to help minimize these failures... plus redesigns from the factory and new belt designs....They keep evolving.
Polaris, the only OEM currently offering a belt-drive in their production sleds still uses a chain drive in many of their mountian-sled models. Even though a simple longer belt and tensioner would allow for more tooth engagement and slightly less weight... along with a standardization of parts (economy of scale)... All of their 3" track equipped models and the RMSHA inspired
Durability, or robustness, in the world of snowbikers on the mountain, in terms of impacts, is what will be proven this season in the consumers hands.
When it comes to Snowbikes... What is the width of a beltdrive equipped snowbike kit... as measured from the centerline of the track to the outside of the belt enclosure, and how does that compare to to a chaindrive. Will a belt drive be more susceptible to "hits" on the hill in a snowbike
On the AXYS-mtn sleds, the lower part of the drive hangs down pretty low on the chassis... protruding past the bellypan of the sled more than any previous year... Will this be the "Achilles Heel" of the design? Already, the aftermarket is making products to protect this area. Will this be more susceptible to "hits" on the hill in comparison to a fully shrouded chaindrive??
Also...I've watched the videos and listened to presentations on the topic of belt drives.
The term "efficiency" always seems to come up... I'm very familiar with this presentation in the sled world of the Polaris snowmobiles and their factory equipped sleds with belt drives... but that efficiency discussion never seems to make it into the realm of track dynos or vehicle specific testing.
...YET... but it will, I'M sure of it.
In a lot of literature I've read, including that from Synchronous belt drive mfgs like Gates... they refer to belt drives "approaching" or "equaling" chain drives.
This paper, from Gates, provides a lot of good ammo for discussion.
http://www.gates.com/~/media/files/...transmission/white-papers/roller-chain-wp.pdf
How does the Synchronous belt drive compare to a roller-chain... or a silent/HYVO chain in terms of efficiency?
Another good paper from Gates parts 1-5
http://ww2.gates.com/IF/facts/documents/Gf000198.pdf
http://ww2.gates.com/IF/facts/documents/Gf000199.pdf
http://ww2.gates.com/IF/facts/documents/Gf000200.pdf
http://ww2.gates.com/IF/facts/documents/Gf000201.pdf
http://ww2.gates.com/IF/facts/documents/Gf000202.pdf
I've heard numbers claimed like 5% more efficient, 30% more efficient, 50% more efficient.
- What are these numbers in referring to?
- Are those for industrial drives, Harley's, sleds, snowbikes??
- How do those numbers apply to snow vehicles?
- What is the real world outcome of this in our products?
If this efficiency does make a noticeable difference in a snowbike/sled what characteristics will be noted by the rider in a positive way and are those offset by other factors?
Does a synchronous belt drive get more power to the track than a chain-drive... in a Snowbike (or a sled) application?
Will characters that are "con's" for chains come into play with the drive speeds we are talking about (FPM)... and for what kind of chain, silent, HYVO, roller?
Does a Belt drive require a larger diameter top and bottom pulley to do the same work and not strip teeth (tooth engagement on the pulley)?
Weight is a big deal these days... Polaris used the QuickDrive™ to get the PRO's to really low production weight... but they don't use this drive system across the board... In fact they only use them on the Mountain sleds, and only certain models... the higher loaded 3" track option uses a chaindrive as do the RMSHA race inspired Assaults and the SKS... the chaindrive is more robust... but slightly heavier with chain, sprocket, cover and oil weight.
The aftermarket belt-drive systems are not as light as the OEM QuickDrive™ as they add weight with a tensioner and longer belt with denser pitch.
On a TS snowbike, a roller chain is used... and it does not require an oil bath..but does require some lubrication/tension periodic maintenance.
On sleds, proponents of belt-drives claim that the belt drive will suffer less damage from a broken belt than a chaindrive from a broken chain... and therefore not leave you stranded on the hill.
This, IMO, IS absolutely true...but, I've rarely even heard of a chain breaking that was properly maintained.... so that point would be better made in the statement that a belt drive will not require as much maintenance...even though that maintenance is low.
I have seen broken chains and the sometimes broken case that can accompany it... but not one of those that I've personally viewed was due to anything but lack of maint (old chain, wrong length chain, never adjusted, never changed dirty/wet oil, no oil, improper oil, leaking seal, too small of top sprocket, etc).. easily avoided. So, for me.... this is not an issue with proper maint.
Another topic of discussion is "Rotating mass"... which can be broken down into two categories... Gyroscopic effect... and Inertial effect.
What are the actual numbers relating to this? How does it affect our riding?
I've heard things like "1 lb of rotating mass equals X lbs of...."
Good for boasting, but that does not take into account the overall mass of a rotating assembly (eg driveshaft and sproket)... or the distance from the center of the rotating assembly...eg, 1lb with a diameter of 5X will have more Gyroscopic and inertial affect than the same weight at 1x diameter... this should be taken into consideration to form a more accurate evaluation of a system, IMO, rather than blanket "general" statements.
Weight, robustness, efficiency, cost, maintenance and integration into the vehicle are all things to consider.
All good topics of discussion.
Have at it
AND PLEASE... Keep it rational and factual and application based (snow powersports) .
If you make a claim that one was better than the other in direct comparison...we're all factors the same? (same exact gear ratio, clutching, fuel, state of tune, or any other mods made at the same time).
.
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