Full suspension with Belt drive - why ?

[Merle Nelson]

This is one thread I had not seen. Thanks For posting on it.

 

[Fast n' Furious]

There was article about an advanced rider that had to change his belt and sprockets every 10K KM, that is a huge amount of Ebike riding.

6213 miles is years for me.

1) There are no off the shelves tensioner you can buy that I could ever find, each manufacturer makes their own for their own bike.
If you figure out your bike could use one from a brand bike, you may be able to buy it as a spare part.
BUT tensioners are intricately linked to the bike geometry and the sprockets used, as how much slack they need to take while maintaining belt tension is a function of the Chain stay variation, and what belt length can be fitted on a given set of front and rear sprocket.
Gates only manufactures certain belt sizes (tooth #), so depending on your chain stay and the sprocket used, you may have to install a belt that already has some slack even at the longest chain path. A given tensioner can only take so much slack, and if that is not enough for your specific bike Geometry / Belt length, it wont do the job.

2) The Hydra does have the ability to open the rear triangle as you can see on the double bolts at the back.

There are tensioners available https://www.santosbikes.com/en/santos/santos-only/santos-belt-tensioner
The center and bottom, rear bolts attaching the motor to the frame are prime candidates for a belt idler plate attachment.
Alignment is not that difficult. The billet tension arm can be spaced outward; the rollers are sold at Grainger's. 'Slack' uptake is based on tension of the spring value - easily known with stock spec tensioners. The tensioner itself can be set differently in it's slots. Same as your cars alternator.
You move the arm closer to increase tension pressure and throw. It's pre-loaded. The degree of change is quite minor, but now it stays in consistent tension.
Here's what Gates says:

Engineering Support and Design Guidelines​

Gates requires manufacturers to follow design guidelines and submit their designs for approval to ensure they function properly–and do not damage the belt’s carbon cords. Guidelines include:

• The tensioner wheel must have a minimum diameter of 50mm, a minimum width of 14mm.
• Tensioners can be mounted on the bottom bracket, or near the rear sprocket on the dropout or stay.
• The tensioner wheel must contact the flat backside of the belt, not the toothed side. Tensioners that push against the toothed side of the belt can reduce contact with the sprockets.
• The tensioner should apply pressure to the slack span of the belt, which normally rotates away from the front sprocket toward the rear. The tensioner should not apply pressure to the tight side.
• Belt tensioners may only be used with premium CDX belts.
• Tensioners must maintain proper belt tension through the entire range of suspension travel.

This article was sponsored by Gates Carbon Drive. Published by Editorial department Contentmarketing on 17 May 2021
See: https://www.bike-eu.com/products-in...rs-enable-full-suspension-innovation-10140505
Here's a wild thought: Sprockets can be 3d printed out of pretty indestructible - but will fail before metal - Nylon reinforced epoxides, (Like my Spyderco's Knife scales). Why not use commonly available $30, toothed belts?
They last 60k on vehicles. The stock tensioners are very reasonable. Only a small, slotted mounting plate, 2 motor bolts with threaded heads (Alibaba), using spacers to move outward or level the pully on the belt's plane and preloading the tension in the most slack position, tighten down. Don't tensioners required 'tension' values stem from 1) the power of the drive, and 2) distance of the belt?
Say, a 30" belt (actually 60") for a 200nm/ 147ftlbs of torque. That requires stout pressure to keep belt firmly, without slack.
Common belts have the matching, required specs - once you have the sprockets.
Not to go on, but the Gates belts market, while fine for pricey (20 - 36nm) 'electric assisted bicycles' is not designed for the +200nm, Titanium souled, 'Asphalt Jungle Beast' outlaw market. Why would they?
Gates belt is 5 x the price of heavier duty, quality "5/8 wide, toothed belts at this length, commonly available in a zillion sizes - and the appropriate tensioners - all that last 20 x as long.
Just my take.
-
Too hot for this old San Diego CA 'weather wimp' buzzard to ride today Parked in my tree.
Hope others enjoyed the fresh air.

I am ever,

Fn'F

 

[scrambler]

An Arm and a Wheel does not make a suitable tensioner for any bike.

I actually just finished a full analysis on a tensioner for a Full suspension bike, and there are way too many details to goo into.

As I said before for bikes with small travel, or chain stay that don't vary much, making a tensioner work can be fairly easy if the geometry can accommodate the tensioner travel, even out of standard pieces like you referred too.
Once you get into Large rear travel bikes like a mountain bike and/or geometry that creates big variation in the chain stay, the problem becomes exponentially more complicated as a single wheel tensioner may never have enough travel or room within the swing arm and frame to take all the slack or maintain proper tension throughout.

Now every problem has a solution, how complicated/expensive that solution ends up being ultimately drive if it is worth it

 

[Leon S. Kennedy]

There was article about an advanced rider that had to change his belt and sprockets every 10K KM, that is a huge amount of Ebike riding.

10,000 Km is less than 1.5 years using my average

 

[Ebiker33]

10,000 Km is less than 1.5 years using my average

That is higher than normal, if it would last 5 years for me, I would would be happy with that.
Reisse and Muller have one that has been out for awhile I haven't heard any complaints from their forums here on EBR on that aspect of the Ebike.

 

[Merle Nelson]

Choices....a beautiful thing. I would love to not maintain a chain as a part of my ebike experience.

When I was a kid I saw footage of bakeries in the Soviet Union. One bread and if you weren't in line early and handled by 10AM they were sold out.

Choices....a beautiful thing indeed.

 

[Leon S. Kennedy]

That is higher than normal, if it would last 5 years for me, I would would be happy with that.
Reisse and Muller have one that has been out for awhile I haven't heard any complaints from their forums here on EBR on that aspect of the Ebike.

I'm replacing mine after 3000 miles. Some teeth on the belt failed, causing slippage.

 

[Fast n' Furious]

An Arm and a Wheel does not make a suitable tensioner for any bike.

I actually just finished a full analysis on a tensioner for a Full suspension bike, and there are way too many details to goo into.

As I said before for bikes with small travel, or chain stay that don't vary much, making a tensioner work can be fairly easy if the geometry can accommodate the tensioner travel, even out of standard pieces like you referred too.
Once you get into Large rear travel bikes like a mountain bike and/or geometry that creates big variation in the chain stay, the problem becomes exponentially more complicated as a single wheel tensioner may never have enough travel or room within the swing arm and frame to take all the slack or maintain proper tension throughout.

Now every problem has a solution, how complicated/expensive that solution ends up being ultimately drive if it is worth it

May be a problem tensioner's can't cope with Ultra's 147.50 ft-lbs of torque. Gates Carbon Belt was designed for bicycles (human , 20nm max).
I see your point on the 'travel changing geometry' issue.

I'm replacing mine after 3000 miles. Some teeth on the belt failed, causing slippage.

I'd like to know more. How did it happen. What were the conditions it failed under? Your Wattage? Rear hub type? FS bike?

 

[scrambler]

May be a problem tensioner's can't cope with Ultra's 147.50 ft-lbs of torque. Gates Carbon Belt was designed for bicycles (human , 20nm max).
I see your point on the 'travel changing geometry' issue.

The problem is not the torque, Gates belt can take way more torque than that.
The problem is the tension they require to do so without slipping.

With the proper tension the belt can take the torque, but what is true, is that as the torque gets higher, the tension required on the belt to prevent it from slipping goes up, and making a tensioner that can apply such tension and take a huge amount of slack is what can become challenging.

 

[Leon S. Kennedy]

May be a problem tensioner's can't cope with Ultra's 147.50 ft-lbs of torque. Gates Carbon Belt was designed for bicycles (human , 20nm max).
I see your point on the 'travel changing geometry' issue.

I'd like to know more. How did it happen. What were the conditions it failed under? Your Wattage? Rear hub type? FS bike?

Wattwagons Cross Tour (hardtail), 2300 Watts, Rohloff rear hub. I was biking quite fast, around 30 mph, in ECO power level 5, when a vehicle pulled out in front of me and I braked very hard and slowed considerably to around 10 - 15 mph. When I began to pedal again at this slower speed, I forgot to lower the power level as I normally would do and a few of the teeth on the gates belt suddenly failed (partially tore off). I can take pictures of the failed belt and post them if that would be helpful.

 

[Fast n' Furious]

Wattwagons Cross Tour (hardtail), 2300 Watts, Rohloff rear hub. I was biking quite fast, around 30 mph, in ECO power level 5, when a vehicle pulled out in front of me and I braked very hard and slowed considerably to around 10 - 15 mph. When I began to pedal again at this slower speed, I forgot to lower the power level as I normally would do and a few of the teeth on the gates belt suddenly failed (partially tore off). I can take pictures of the failed belt and post them if that would be helpful.

I'm thankful you commented and wouldn't think of doubting your veracity. Posting photos would be helpful for many.
That's the build I'm considering, and I've fretted: 'Is the Ultra's 147Ft-Lbs (@200nm) compatible with drive systems available - esp. Gates Carbon Belts?
The good: Actually, if the belt shreds before the Kindernay krunches (which is next up), it's not so bad we have a weak link.
The point to me: It appear just the torque sensor is sufficient to wreak havoc - without constant aware supervision and attention to settings.
For my machine, I want a belt and drive drive that will burn rubber - not scrap the belt, rear end/ gearbox, and hit +30mph. Sure sounds like 3 speeds, a fat belt and the right gearing.
Of course, stripping could be you were out of tension specs, but if it was the frame flexing, the belt would come off.
However, what you describe are not symptoms of Gates' renowned, finicky 'outside of tension specs' outcomes - teeth stripping says something else: Weak link is the belt itself - AND multiple teeth chewed, but not a broken belt says: It's not mistreatment - backbending, etc.
I note that Optimax spun his belt - but declines to address the question of 'the technical parameters (wattage, etc), or any circumstances' providing thoughtful info - beyond the scenery and state of fruit diet schedules, toting three batteries ... vis-a-vis pannier storage capacity at the time.
That's 36lbs of batteries - no telling how many Bananas. He's +200lbs.
I'm 140 soaking wet and run 12lbs of battery.
He could have been in 14 and juiced at 750w, or 2300w - at whatever level. Frustrating.
-
Really like to hear from you, the settings that work in the 'real', consumer 'world' with your '2300w CT, if you could elaborate on your anecdotal understanding of the correct settings - to avoid 'improper high torque' outcomes.
If I go it alone, I'll probably break everything, because I ride ...

... Fast and Furious,

Thanks,

Fn'F

 

[Fast n' Furious]

Does it have to be titanium ?

Yes, sintered, honeycombed Ti interior skeleton, with a bonded exoskeleton of resin impregnated Kevlar.
You even can build in an internal battery - for those that care.
And for FS bikes, the fulcrum MUST be at the drive shaft. Why play 'lets fix a problem', when you can completely avoid it?

 

[pushkar]

There was article about an advanced rider that had to change his belt and sprockets every 10K KM, that is a huge amount of Ebike riding.

Interesting.

 

[opimax]

Ahh I have found the 36lbs of batteries ! i carry a total of 3 batterries, I or 2 connected ((depending on how the bike is configured) and a spare or 2. I only use 1 pannier on the Allant with 1 spare and the other bikes it’s 1spare in each of 2 panniers. Sometimes if I drive to a trail I leave the spares in the van and make sure the van is strategically placed for battery efficiency. I am so used to carrying extras I do it on days I don’t really have time to use 1 complete battery but you never know when the weather will be perfect and the wife goes out on her own and leaves me with additional riding time….I am ready! i believe I carry 1 less battery than you think though.
if you ask a question I will answer it but you won’t ask a simple question.the info below was already posted and I think it answers your questions about what happened. I can’t be sure of the gear as there is no gear indicator so I can’t be sure which gear I am in he riding . I can tell you I believe I am the correct gear for what I am doing at the moment or I would shift, this is by feel. Every shift on my bike does not feel the same I am not sure on some shifts if it changed 2 or 3 gears even though I maxed traveled the shift button, maybe it is my Kindernay which is not currently100%.on this part of the trail I would think I pushed it twice and and I can’t be sure whic gear I was in before, did you know there is no gear indicator on Kindernay and 14 choices?

I am really about 195 currently on the way down I hope thank you very much . my belt came off i think it was at an angle , wheel was not centered, not sure if it spun or just came off sideways . I was not in top gear as I shifted for a large large hill. I did up the power for the hil going to power mode from eco mode in level 3 or 4 . I did not take notes. I was more concerned on how I was getting home 40 miles away! I don’t think there is an owners manual for the bike certainly nothing I received addressed how reinstall a belt . There may be a YouTube on it I have not seen it. I didn’t think the belt would need to reinstalled in the 1st month of ownership. I don’t want /enjoy working on bikes. I want to ride them or I would DIY. I worked on my cars to save money I no longer need to do that and the same with bikes but never learned /worked on a belt drive before my incident.
You think not giving you every detail is frustrating, your last word about my posting , Frustating is having a new $ 10,000 bike break in the 1st month 40miles from home with a new mechanism you never seen before in 90 degree heat no shade with a bad back trying not scratch the damn thing and some one telling you you didn’t give enough details about the incident …and they were already posted once before

 

[Merle Nelson]

Well...even in your frustration you give more great details and paint a detailed picture that helps me to see more.

In speaking of shifting by feel and being in the right gear etc I can fully believe it. My friend Adam had a tree service business where he specialized in doing property clearing for vineyards to be put in. I helped him out a bunch at one point in life by running his large excavator and large stump grinder. They both have such an array of knobs and buttons that it boggled my mind. I noticed that I ran them not by thinking what each control did but by starting out a bit slow and then just thinking what result I wanted and my body/mind knew what control to move to get that. He use to say that my operating was the smoothest and most efficient he had ever seen. (My personal metaphor was that I became one with the machine.)

Top end equipment can be a tad finicky at times. I'm sorry to hear of your troublesome experience(s). But, even in that sharing, it tells me I am on the right path going toward builds with Kindernay and belts as soon as available for my application.

Thanks for taking the time to post Opimax.

 

[Merle Nelson]

Follow on thought.... The reason I see some things as "finicky" and am still optimistic as opposed to being disheartened is because there are indications of what might have had it happen (wheel off alignment ) and there are copious bikes running the gates belt with no issues and getting all the benefits of a belt. Hence once the bug is worked out (alignment) a person is off to the races with all the benifits to be enjoyed.

 

[Deacon Blues]

While watching a Youtube video on belt drives for bicycles the presenter mentioned that there was a company that made a spiced belt. With this belt you don't need a bike with a split frame to install or take off the belt. Very interesting.

Belt Drivetrain Components For Bicycles | OEM & Dealer

Offering belt drivetrain solutions for E-bike applications for OEMs and Dealers internationally! Innovating the first splittable belt that doesn't require a split in your frame. We also offer traditional, looped belts for high powered motors. Our talented group of engineers will develop your...

www.veercycle.com

 

[reed scott]

JMO and mostly just spitballing but These IGHs seem fine for commuter/pavement bikes but perhaps not so much for bikes meant for halfway serious trail riding. I won't take them seriously for the SUV type biking I do until they specifically come out with versions for 'off road' use. Right now the benefits do not seem to outweigh the problems seemingly inherent in their mechanical complexity ... for my use anyway.

 

[Merle Nelson]

While watching a Youtube video on belt drives for bicycles the presenter mentioned that there was a company that made a spiced belt. With this belt you don't need a bike with a split frame to install or take off the belt. Very interesting.

Belt Drivetrain Components For Bicycles | OEM & Dealer

Offering belt drivetrain solutions for E-bike applications for OEMs and Dealers internationally! Innovating the first splittable belt that doesn't require a split in your frame. We also offer traditional, looped belts for high powered motors. Our talented group of engineers will develop your...

www.veercycle.com

Deacon, it's not my place to say obviously, and I don't know for a fact, but I have suspected WW was about ready to bring out something on this order and more. More able to handle torque than the gates, more retrofitable.

When I add up all the comments that have been written in various threads it seems to be the only thing that makes sense. The only worst part I remember reading was that it might be 2022 before we see it. I can wait.

 

[scrambler]

While watching a Youtube video on belt drives for bicycles the presenter mentioned that there was a company that made a spiced belt. With this belt you don't need a bike with a split frame to install or take off the belt. Very interesting.

Belt Drivetrain Components For Bicycles | OEM & Dealer

Offering belt drivetrain solutions for E-bike applications for OEMs and Dealers internationally! Innovating the first splittable belt that doesn't require a split in your frame. We also offer traditional, looped belts for high powered motors. Our talented group of engineers will develop your...

www.veercycle.com

The problem with split belt is that they definitely cannot take the 2300W of an ultra with X1. And yes it has been tried