Belt drive?

pennybags

Active Member
@pushkar we keep hearing about the belt drive for the FS bikes. I know you are busy, but a few questions...

1. Is there an ETA ?
2. Will it be backward compatible with the current hydra frames?
 

pushkar

Well-Known Member
Hey @pennybags I know this topic comes up multiple times. I
Right now we are laser focused on building the bikes that have already been ordered (including yours :) ), as we get the frames and batteries in. We are also looking at expanding to a new facility.

That being said, even though Tons of high priority items - but have not forgotten about the belt. The issue though is - just anecdotally - adding a belt to FS means riders have to switch to a hub (kindernay, ~1300 / 1400) + cost of the belt drive transmission (~250 for our part + cost of belt and cogs, so around 400-500).

I know you have a kindernay on your Helios, so for you the delta will be small (just another built wheel). However for most people, this gets into ~6k+ territory (even if you get the stock bike).

Thoughts on that ?

edit: I mean it will still be much cheaper than Nicolai and R&M. (both appear to be 10k+).. so may be cost is not an issue ?
 
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pennybags

Active Member
$6.5-$7k for a bike that has all the features you are saying + belt drive, is in regular bike territory dude.

I was about to tell you about the pricing for Nicolai ... ha ha
 

biruja

New Member
I'm not sure a belt is a good idea on a 165 mm rear suspension bike. The purpose of a belt is to reduce maintenance but adding in the cog and tensioner to a FS bike (hydra) is not nearly as a straight-forward as a belt on a hard tail. If you want added reliability and improved maintenance, I think a hub with the single gear up-front gives it to you. This should be a WW Labs project not an untested (edit: or quickly pulled together) feature, IMO.
 

PedalUma

Well-Known Member
Region
USA
Full suspension belt drives require a tension idler pully to take up slack. With steel frames you do not need a full suspension to have a great ride. A better ride. Problem solved with a better solution, less complication and while opensource. I am converting a Litespeed next week. Did a Surly yesterday and working on a Chormo today. It will get a half-link chain that is three times longer lasting than a regular chain - about the same as a belt.
 

Timpo

Well-Known Member
I'm not sure a belt is a good idea on a 165 mm rear suspension bike. The purpose of a belt is to reduce maintenance but adding in the cog and tensioner to a FS bike (hydra) is not nearly as a straight-forward as a belt on a hard tail. If you want added reliability and improved maintenance, I think a hub with the single gear up-front gives it to you. This should be a WW Labs project not an untested (edit: or quickly pulled together) feature, IMO.
Well it's been done on 160mm bike.

Kat Belt-19812.jpg

Belt-13.jpg
 

Timpo

Well-Known Member
I'm not sure a belt is a good idea on a 165 mm rear suspension bike. The purpose of a belt is to reduce maintenance but adding in the cog and tensioner to a FS bike (hydra) is not nearly as a straight-forward as a belt on a hard tail. If you want added reliability and improved maintenance, I think a hub with the single gear up-front gives it to you. This should be a WW Labs project not an untested (edit: or quickly pulled together) feature, IMO.
actually, 165mm is irrelevant.

it's all about geometry, where axis is.

in theory, a full suspension bike may not need a tensioner if chainstay (swingarm) length does not change while travel.
If that makes sense..
 

scrambler

Active Member
Well the travel is relevant, but yes you are right it all depends on the offset between the Bottom bracket and the swingarm axis.
Based on that offset, when the wheel moves up, the belt path becomes bigger. How much bigger depends on that offset, and the bigger the belt path changes between the low and high position, the more slack has to be taken by the tensioner.
But for a given offset, the more travel, the more belt path differential, the more slack has to be taken :)
 
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BarnBoy

Well-Known Member
Region
USA
City
Pleasanton, CA
Hey @pennybags I know this topic comes up multiple times. I
Right now we are laser focused on building the bikes that have already been ordered (including yours :) ), as we get the frames and batteries in. We are also looking at expanding to a new facility.

That being said, even though Tons of high priority items - but have not forgotten about the belt. The issue though is - just anecdotally - adding a belt to FS means riders have to switch to a hub (kindernay, ~1300 / 1400) + cost of the belt drive transmission (~250 for our part + cost of belt and cogs, so around 400-500).

I know you have a kindernay on your Helios, so for you the delta will be small (just another built wheel). However for most people, this gets into ~6k+ territory (even if you get the stock bike).

Thoughts on that ?

edit: I mean it will still be much cheaper than Nicolai and R&M. (both appear to be 10k+).. so may be cost is not an issue ?
@pushkar let me know when you are ready!!! Please put me down on your list....
 

BarnBoy

Well-Known Member
Region
USA
City
Pleasanton, CA
Well it's been done on 160mm bike.

Kat Belt-19812.jpg

Belt-13.jpg
@Timpo, that bike you showed looks amazing! Thank you for sharing that as it helps me with a debate I have been having with a fellow nerd engineer. He too loves bikes but absolutely sees zero purpose for a belt drive. Almost every negative comment he has given, I have been able to shove it back down his throat (mostly thanks to the forum!). He also despises eBikes! Well your reference to www.Zerodebikes.com helps stuff his latest comment; “analog bikes would never use a Gates belt as it is too inefficient”…..

Beautiful bikes! But that stated, they missed one a very important design consideration. It has been mentioned in the forum before, but single sided belts like this are not recommended to use a backside idler (tensioner); R&M bikes too! The belts being used are recommended to use an inside idler for best belt lifetime. I reference page 69/112 (printed as page 67) section V. Idler Usage in: www.gates.com/content/dam/gates/home/resources/resource-library/catalogs/light-power-and-precision-manual.pdf to see actual verbiage...

Since I jumped down the eBike rabbit hole I have been banging my head on belt drive solutions. A bike chain is WAY heavier than carbon belt, and it is able to keep on the cassette/cogs just fine with a simple derailleur spring idler. Also, why would you want to place the idler near the suspension pivot point as now you have the swing arm lever forces with rider weight getting applied from suspension compression/rebound (like a nutcracker). Plus, you also expose it like the chain-ring bash-rings versus natural protection with the 26 – 29 inch wheel in the back. IDK…

So, I started a very simple model of the Hydra based on published measurements (not sure if accurate, but IMHO doesn’t matter!) and think I know what the ballpark forces an idler can expect at different locations in the Hydra XL frame and swingarm design. @pushkar is absolutely correct that this is not as simple as I thought it should be. Plus, big guys like me are likely to break stuff!!! I expect that and fully volunteer to help make the WW belt drive design system bullet proof. I have full confidence in Pushkar, that it will be done right and properly vetted before being released…

@pushkar – You can gladly have my $$$$ when you are ready…
 

Ebiker33

Well-Known Member
@Timpo, that bike you showed looks amazing! Thank you for sharing that as it helps me with a debate I have been having with a fellow nerd engineer. He too loves bikes but absolutely sees zero purpose for a belt drive. Almost every negative comment he has given, I have been able to shove it back down his throat (mostly thanks to the forum!). He also despises eBikes! Well your reference to www.Zerodebikes.com helps stuff his latest comment; “analog bikes would never use a Gates belt as it is too inefficient”…..

Beautiful bikes! But that stated, they missed one a very important design consideration. It has been mentioned in the forum before, but single sided belts like this are not recommended to use a backside idler (tensioner); R&M bikes too! The belts being used are recommended to use an inside idler for best belt lifetime. I reference page 69/112 (printed as page 67) section V. Idler Usage in: www.gates.com/content/dam/gates/home/resources/resource-library/catalogs/light-power-and-precision-manual.pdf to see actual verbiage...

Since I jumped down the eBike rabbit hole I have been banging my head on belt drive solutions. A bike chain is WAY heavier than carbon belt, and it is able to keep on the cassette/cogs just fine with a simple derailleur spring idler. Also, why would you want to place the idler near the suspension pivot point as now you have the swing arm lever forces with rider weight getting applied from suspension compression/rebound (like a nutcracker). Plus, you also expose it like the chain-ring bash-rings versus natural protection with the 26 – 29 inch wheel in the back. IDK…

So, I started a very simple model of the Hydra based on published measurements (not sure if accurate, but IMHO doesn’t matter!) and think I know what the ballpark forces an idler can expect at different locations in the Hydra XL frame and swingarm design. @pushkar is absolutely correct that this is not as simple as I thought it should be. Plus, big guys like me are likely to break stuff!!! I expect that and fully volunteer to help make the WW belt drive design system bullet proof. I have full confidence in Pushkar, that it will be done right and properly vetted before being released…

@pushkar – You can gladly have my $$$$ when you are ready…
As to the Gates belt drive look no further than Harley Davidson Livewire E-Motorcycle which sells for 37K, uses a belt drive, they took that same tech and rolled it into their new Ebikes the Serial 1.
Watt Wagons was way ahead of everybody he used it from day 1.