Pole Internal Gear Transmission /MGU Integration Thread

[slickrock]

Update: Above image says it all. Taken without permission from V86.

A number of people in this forum are expressing interest in some form of internal geared transmission system integrated with Pole EMTBs, whether it be new-fangled motor/gear units (MGU) or hub-based integration with a secondary objective of eschewing chains in favor of a kevlar-based belt drive. There have been a number of posts on this topic that I felt it the need for a separate thread to discuss this rather than clog up the other threads.

From a product perspective, it is clear that having a combined internally geared transmission system with e-bike motor in a single mechanism (i.e. MGU) is the best synergistic confluence of bike technologies for full-power EMTB. Combining these two technologies affords an unsprung, automatic transmission, sealed mechanism, low-maintenance drivetrain solution and can open up the option to use belt drive instead of chain linkages and dangling derailleurs. Additionally, the downsides of internal-gear solutions, such as added weight and reduced efficiency, don't rear their heads as much with full-power, enduro-sized e-bikes, as they are already heavy and power-assisted to begin with.

But... we have to wait for this technology to develop, mature, and become reliable, and without the big players entering the market (SRAM, Shimano, Bosch) placing bets on a particular solution for a boutique bike manufacture may be too much to currently entertain. Poles' EMTB product space is arguably too crowded already with quite a bit of marketing effort put forth to distinguish the brand new Sonni from the still relatively new Voima. Pole currently has no internal gear offerings and it’s not clear if Pole would create a new EMTB model or graft a solution onto its existing offerings at some in the future. Of course, we could abandon Pole and jump to the likes of Bulls Bikes (or maybe Orange when gets is prototype out the door) to get an MGU fix, but we'd also be abandoning the affinity to Pole's geometry, design, performance and manufacturing prowess.

In meantime, I'm exploring getting close to nearly 90% of the MGU benefit by incorporating an internal geared hub (IGH) and integrating it with the Bosch motor via a Gates CDX belt-drive. The target bike is a Sonni K1, which I have on order, and it will probably be sometime in November before it arrives. For the IGH, I'm strongly in favor of using the Rohloff Speedhub, for a number of reasons, namely that I’ve been using a Speedhub for about 8 years on my acoustic dual suspension MTB (see below) with flawless performance and near-zero maintenance.

I would like to hear how others feel about alternatives such as Nuvinci, Nine 3x3, Kindernay, etc. I’ll also be exploring electronic shifting as part of the solution, as this would be implied with an MGU setup, not to mention that a lot of folks are choosing AXS/DI2 electronic shifting on their current rigs. My intention is to add to this thread with my findings and welcome feedback.

 

[Alexbn921]

Not the first one

 

[tooFATtoRIDE]

Hi Slickrock,

Thank you for separating this discussion - brilliant idea. Hopefully this will become a good source of info for those interested in internal hubs.

I have done some digging on Kinderlay Hub. There are two options: 14 gear version with a range of 548%, and 7 gear version with a range of 438%. Other than the number of gears, range, weight and price, there is one crucial difference: the KInderlay VII used a normal 6-bolt disc brake rotor whereas the Kinderlay IV uses a proprietary 7 bolt system.

The shifting is hydrolic so some bleeding is involved if routing the two necessary cables through the frame. I have found no mention regarding electonic shifting.

Some interesting info could be found on the German distributor's website: Kindernay VII – trail.camp

One thing that worries me is that the chainline for Gates Belt is 45.5mm. I am not sure what's the achievable chainline on Voima or Sonni but from my own experience with Gates belt, the chainline needs to be perfect. Perhaps there is some room for adjustability, I am not sure myself.

I have found some vids on YT that could be of use:

From 2m50sec:

User video review:

Kinderlay YouTube online channel:

https://www.youtube.com/@KindernayCorporation/videos

Some tech info is also attached.

Lastly, interesting discussion on one of the German emtb forums: Kindernay VII IGH and HYSEQ Onesie shifter

Some issues discussed on this very forum: Dengfu E22 Frame Thread

There are also some doubts whether they are still fully operational. See comments section to this article: Buyer’s guide to internal gear hubs | Everything you need to know

 

[tooFATtoRIDE]

@slickrock I have found a very interesting step-by-step hands-on guide on installation of a thru axle bike. I hope this would be of you when you start with your Rohloff conversion (if you choose this particular hub make).

Installed a Rohloff Speedhub 14, IGH on my mid-drive Luna Z1 Ultra Mag

After a year of researching, speaking to owners and dealers of the Rohloff Speedhub, I've decided to ditch my 12-speed cog/derailleur system and install the Rohloff Speedhub 14 IGH on on my carbon fiber Luna Z1 Ultra Mag. The kit arrived by UPS today. I'm very excited to build the wheel, install...

forums.electricbikereview.com

 

[Onetime]

Too bad neither the Rohloff or Kindernay didn’t use a belt drive on the examples shown.

 

[tooFATtoRIDE]

I think the key issue here is finding a suitable belt tensioner.

Too bad neither the Rohloff or Kindernay didn’t use a belt drive on the examples shown.

I think the reason for it is a lock of options for belt tensioner. There is one for Pinion (PINION Riemenspanner BT1 Gates CDX Art.Nr. P8555) but I am not sure if the mounting hardware would be a straight fit for the two bashguard mounting points on Voima. For Sonni, my knowledge is non-existant so I cannot comment.

Even if the mounting hardware was a straight fit, the position would not be optimal. Probably the best current execution of this tensioner could be seen here:

It is not as exposed as noted in other Pinion equipped bikes but still in the way of potential rock or root strikes.

I have found this on our forum but I do not think this type of tensioner would be of any use for Pole bike owners.

eMountain Biking with an Internal Geared Hub (the Rohloff)

@paulmoir great video, thank you. Have you noticed any difference in rear shock responsiveness ? 1/2 kilo is quite an increase in unsprung mass

www.emtbforums.com

For those interested in Rohloff, it is worth mentioning limitations to the sprocket ratios:

I mentioned this as with a large front sprocket one might have its edge extending beyond either the frame (Voima) or the engine (Sonni). No big deal, just need to keep in mind that a bashguard could be useful.

If someone one here has any good connections with the Nicolai Bicycles team in Germany, it is worth inquiring whether the would sell their GBT3 belt tensioner for non-Nicolai users. The benefit of that particular tensioner, if you are ok with having 39t the max size of your sprocket, is already integrated bashguard. Obviously the question remains if it would fit.

 

[slickrock]

Yes, the belt tensioner is the the most difficult part of the solution to overcome, IMHO. And not all the solutions out there appear that elegant - as witnessed by the tensioner for the Pinion MGU, which is in a positively dreadful spot.

As mentioned, Nicolai would appear to solve the bike tensioner puzzle, especially their newer version, which appears to have these benefits:

1. Works with the Bosch motor.
2. Looks to be bolted onto the same mounting points of the motor itself rather than on the frame, which is critical for it to work on a Pole.
3. The design seems to have improved, where the spring mechanism in now tucked transversely and safely behind the motor rather than under the motor where there is a high risk of strikes. One hopes that there is enough space between the motor and rear tire for clearance. A mullet configuration may help in this regard.
   
4. Because of the transverse mounting, the tensioner appears is also bolted on the opposite side of the the motor as well - An impressive and aesthetic design stroke to say the least. OTOH, it might prove more challenging to install on a Voima or "jock-strapped" Sonni, not to mention possibly limiting belt alignment tuning.
   

I've looked a a number of tensioner systems, but pretty much all them have been disqualified because of not complying with 1 and 2 above. Except Nicolai (do share if there are others out there that could work). I'm not sure but I believe the tensioner is made by Universal Transmissions, which looks to be German Gates distributor as well. I've reached out to them but their relationship is tight with Nicolai, so they suggested I reach out to Nicolai, which I've yet to do. It's a bit a of delicate play to ask for a company's custom bike part without owning their bike.

Of course all this nastiness could be avoided by just going with chains for internal gear solution, of which there are a number tensioners to choose from, but I feel belt drive to be an essential motivation to pursue this effort to begin with.

 

[slickrock]

Hi Slickrock,

Thank you for separating this discussion - brilliant idea. Hopefully this will become a good source of info for those interested in internal hubs.

I have done some digging on Kinderlay Hub. There are two options: 14 gear version with a range of 548%, and 7 gear version with a range of 438%. Other than the number of gears, range, weight and price, there is one crucial difference: the KInderlay VII used a normal 6-bolt disc brake rotor whereas the Kinderlay IV uses a proprietary 7 bolt system.

The shifting is hydrolic so some bleeding is involved if routing the two necessary cables through the frame. I have found no mention regarding electonic shifting.

Some interesting info could be found on the German distributor's website: Kindernay VII – trail.camp

View attachment 125415

One thing that worries me is that the chainline for Gates Belt is 45.5mm. I am not sure what's the achievable chainline on Voima or Sonni but from my own experience with Gates belt, the chainline needs to be perfect. Perhaps there is some room for adjustability, I am not sure myself.

I have found some vids on YT that could be of use:

From 2m50sec:

User video review:

Kinderlay YouTube online channel:

https://www.youtube.com/@KindernayCorporation/videos

Some tech info is also attached.

Lastly, interesting discussion on one of the German emtb forums: Kindernay VII IGH and HYSEQ Onesie shifter

Some issues discussed on this very forum: Dengfu E22 Frame Thread

There are also some doubts whether they are still fully operational. See comments section to this article: Buyer’s guide to internal gear hubs | Everything you need to know

The Kindernay play is interesting and thanks for providing some more detail here. Looks like the product has advanced a bit in the last 3 years, especially the VII hub which seems to be well suited for EMTBs. I like that it's a much lighter hub, which would help in the unsprung weight department. The VII is markedly less expense and I like the hub cage concept a lot. But there are other issues looming:

1. The hydraulic setup and shifter seems to add a chunk of weight back into the solution. The design uses 2 hoses for shifting up and down, which IMO, could have been designed with only one hose (I get 2 cables, since you can only pull pull on cables, but hydraulics work in both directions, at least closed systems).
2. the hydraulic actuator is on the drive side where the sprocket is located, instead of the non-drive side (like with the Rohloff). This limits belt line flexibility and keeps the belt line too far inward, which could limit tire width, not to mention belt line adjustment challenges on the front sprocket and belt tensioner.
3. No current electronic shifting solution
4. Very few examples of belt drive solutions out in the wild. At least, however, it appears possible.
5. I've yet to actually audition one on a bike, and doing so is proving difficult in the U.S. While I would expect the shifting to be crisp, I really would need to feel how the shifting works under load, especially since there is no current electronic shift solution what could better time the gear shifts when the pedal stroke is unweighted.

Has anyone on forum tried a Kindernay and can share the some feedback?

 

[tooFATtoRIDE]

Very interesting video compaison between belt and chain experience on the same Zerode bike.
First seen on this discussion on our very forum: Gearbox EMTB's that you can buy (+IGH bikes)

 

[slickrock]

Very interesting video compaison between belt and chain experience on the same Zerode bike.
First seen on this discussion on our very forum: Gearbox EMTB's that you can buy (+IGH bikes)

Regarding the belt drive video, 3 things stand out:

1. Tensioner design and robustness matters.
2. Snubbers should not be overlooked
3. Having to buy another rear end is is just too much. With Voima and Sonni, no problem.

Now, regarding the EMTB gearbox thread, I somehow missed it and it's quite useful from a product landscape perspective, so much so that I'm going to include mention when I edit the OP soon. Some thoughts on it:

1. Plenty of Rohloff integrated solutions. SVO Chrono, which has a bosch motor, has a tensioner directly on the hub! Won't work for the Poles but cool just the same - obviates a snubber and the only way this is possible is because the Levo-cloned bike looks to have minimal chain growth. That said, Nicolai still appears to be the best solution for a tensioner for this thread.
2. Revonte MGU is just fabulous. I got interested in this motor 3 years ago but they were hush about how the gearing works. With the mechanism now fully described, it's transmission is profoundly simple and has no discrete gear steps. It's basically a CVT, but with with a direct drive motor managing gear ratios. The Euro bike demo shows just how quickly you could accelerate with the thing, always in the sweet spot of the torque range. It would be a travesty if this design does not take hold. Bosch should just buy out this company in a heartbeat.

Parting question. I've ask this before: what is the chain growth of a Voima 190mm (don't have mine anymore)? There's very little belt deflection on the SVO and it would be cool if the Voima is similar.

 

[slickrock]

...

1. Revonte MGU is just fabulous. I got interested in this motor 3 years ago but they were hush about how the gearing works. With the mechanism now fully described, it's transmission is profoundly simple and has no discrete gear steps. It's basically a CVT, but with with a direct drive motor managing gear ratios. The Euro bike demo shows just how quickly you could accelerate with the thing, always in the sweet spot of the torque range. It would be a travesty if this design does not take hold. Bosch should just buy out this company in a heartbeat.

...

Didn't mean to jinx things, but Revonte is now Bankrupt! They are searching for takers of the IP, so the silver lining here is the that some big player like Bosch, or a big bike brand like Specialized or Trek, might scoop this tech up (fingers crossed). Goes to show you that its very very hard to enter into to enter the motor market with 500lb gorillas like Bosch, Shimano, Brose/SRAM, and Bafang. The irony is that none of these players have an MGU. Please don't let this tech wither and end up in scrapheap of failed bike tech.

 

[tooFATtoRIDE]

I have been an early adopter of Pinion internal gearbox. I am not sure when it was first introduced but I committed to this design in late 2015.

For me, the acid test was this: which established bike manufacturer has adopted this solution. It was Nicolai which was one of the first early adopters. This is also the bike I bought (Nicolai ION GPI). Ever since I started observing what new bike tech they would put on their bikes.

In the context of our discussion regarding the internal gear hubs, Nicolai has been using Rohloff for a very long time. During Eurobike 2022 they displayed a bike with the Kindernay hub: However, this setup did not become available to purchase from them.

For 2023/2024, they have two internal gear hub options: Rohloff (GT1 EBOXX FDT, 10.499,00 € and GT1 EBOXX WRT, 10.499,00 €) and 3X3 NINE (GT1 EBOXX EWB, 10.499,00 €). This is the acid test for me and these would be the hubs I would consider today for the Voima IGH Belt project.

One might argue that Rohloff and 3X3 NINE are both German manufacturers and this is might be some sort of national solidarity for Nicolai. For me personally, this would not be enough for Nicolai to put such a crucial component on their bike if they were not satisfied with the quality and the manufacturer's ability to actually deliver sufficient number of products.

I think Rohloff is fairly well known. I want concentrate on research on 3X3 NINE as it appears to me a very good alternative to Rohloff.

 

[tooFATtoRIDE]

I have asked 3X3 for info regading their hub availability to the end user. This is what I got in return, not looking too great to be honest.

----------------------------------------
At the moment, we do not offer our gears to retailers or end users.

You can already buy an e-bike with our hub from the manufacturer Nicolai Bikes (NICOLAI GmbH), Cargo Factory (Lastenrad Konfigurator - Alle Cargobike Optionen mit einem Klick), Mi-Tech (MiTech – Handgearbeitete, individuelle Mountain Bikes), Portus Bikes (Portus Cycles – Fahrräder aus Stahl – Konstruktion & Entwicklung – Prototypen- & Kleinserienfertigung) and Mäx & Mäleon (Konfigurieren - Mäx & Mäleon) also offer our hub in their bikes.

Other bicycle manufacturers such as Quantor and Muli will follow shortly.

To be included in your future dream bike, you can do us a favour and ask your bike company/brand about the availability of 3X3 in their bike portfolio.
----------------------------------------

 

[slickrock]

Ok, so I auditioned, albeit briefly, the Rohloff E-14 electronic shifting with the Speedhub, Bosch CX motor and Gates belt drive and what I came away with was way beyond expectation. I used to think that electronic shifting was just icing on the cake, but I’m convinced otherwise now.

One consequence with using a Speedhub, Pinion, or similar internally geared transmission (3x3 excepted) without motor assistance, is that although you can freely shift at rest, it can be challenging to shift under medium to high loading at the pedal without developing a technique of pausing at the up/down stroke when the pedal is the most unweighted. This is not a problem at higher speeds and higher gears when the rider has nominal forward momentum, but when you are on a very steep incline, going forward very slowly and then need to downshift, pausing at any length can rob the much needed momentum to keep you balanced. Again, technique comes into play here to make it easier, but it’s not really easy per say.

Test:
I visited Propel Bikes in Long Beach and rode one of their R&M city bikes with said drivetrain tech. The terrain was city/residential streets with no hills/grades. I simulated shifting under load by heavy handing both brakes will shifting and standing up and hammering on the pedals. Without hamming the brakes, the shifting was flawless throughout. Even in the Speedhub’s sometimes touchy transition between gears 7 and 8, where the rack of gears internally switch from the bottom half to the top half. But then again this was expected. Under heavy load with a lot of brake grip with me standing off the saddle was the real test. What I found was that the system would perfectly pause to allow shifting without any discernible binding in the lowest set of gears for, most importantly, downshifting, but also with upshifting. This pause is brief enough so as to not produce a feeling of forward rider momentum loss, which would have been especially pronounced at low speeds. To me, this aspect effectively kills off my primary negative of using a Speedhub on a MTB (per above), which is well-timing the shifts under medium to high loads.


Beyond this, there was something intangible, yet important, about the test: the Bosch and Speedhub felt super integrated, as in what it would feel like to ride an MGU (which I haven’t, so I’m speculating here). My sense is that Bosch put some time in the modded firmware to make the “Bosch part” of the power profile feel consistent. So when I changed gears, it was as if the gears were actuating within the motor. I know exactly what a Rohloff/Gates feels like without a motor and exactly what a Bosch CX feels without an internal gear hub, so I can firmly say, the whole is not only greater than the sum of the parts, but that the integration seems intrinsic somehow, as if it was always thus (especially with the belt). And MGUs probably more so with afforded automatic shifting - after all, cars we drive have transmissions integrated with motors, often in the same block. I’m absolutely convinced at this point that derailleurs will never feel integrated with motors, despite Shimano and SRAM latest efforts. Derailleurs were there long before the motors came along, evolving separately in a way that never the twain shall meet.

 

[tooFATtoRIDE]

I got in touch with Rohloff regarding getting info on which of my local Rohloff resellers has the A12 test kit. As expected, the response was less than satisfactory. For some reason, this becomes a norm and the clients are treated as cash-cows, nothing more.

@slickrock - there was something interesting for the Rohloff E14 integration with the Bosch smart system worth knowing:

The E-14 system will only function when a special container file is installed into the Bosch system. Bosch will not supply this and Rohloff cannot. The E-14 system can therefore only be retrofitted to bicycles where the OEM manufacturer is able to supply and install this software container file. We will require written confirmation of this before we can sell the system to you chosen dealer.

Please contact the manufacturer of your bicycle and obtain this confirmation. Without it, you will only have the option of using the standard, mechanical (cable operated) SPEEDHUB versions.

Yeah, not as easy then.

 

[V86]

(Photoshop)

 

[tooFATtoRIDE]

I got in touch with Rohloff regarding getting info on which of my local Rohloff resellers has the A12 test kit. As expected, the response was less than satisfactory. For some reason, this becomes a norm and the clients are treated as cash-cows, nothing more.

@slickrock - there was something interesting for the Rohloff E14 integration with the Bosch smart system worth knowing:

The E-14 system will only function when a special container file is installed into the Bosch system. Bosch will not supply this and Rohloff cannot. The E-14 system can therefore only be retrofitted to bicycles where the OEM manufacturer is able to supply and install this software container file. We will require written confirmation of this before we can sell the system to you chosen dealer.

Please contact the manufacturer of your bicycle and obtain this confirmation. Without it, you will only have the option of using the standard, mechanical (cable operated) SPEEDHUB versions.

Yeah, not as easy then.

Some positive market development for @slickrock and others potentially considering electonic shifting for Rohloff Speedhub

Bearing in mind the Rohloff's less than satisfactory response above (at least for me) please watch the entire below video. It is in German , which I understand to certain degree but you could use the YT auto-translate function.

In my view this might be a very good alternative, especially if you do not need the total integration with Bosch power system. Whether this option would work for you is not for me to say but it is great that there would be an alternative to E14 system.

Enjoy!

 

[TheSnowShark]

View attachment 128296
(Photoshop)

I want one !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[slickrock]

I got in touch with Rohloff regarding getting info on which of my local Rohloff resellers has the A12 test kit. As expected, the response was less than satisfactory. For some reason, this becomes a norm and the clients are treated as cash-cows, nothing more.

@slickrock - there was something interesting for the Rohloff E14 integration with the Bosch smart system worth knowing:

The E-14 system will only function when a special container file is installed into the Bosch system. Bosch will not supply this and Rohloff cannot. The E-14 system can therefore only be retrofitted to bicycles where the OEM manufacturer is able to supply and install this software container file. We will require written confirmation of this before we can sell the system to you chosen dealer.

Please contact the manufacturer of your bicycle and obtain this confirmation. Without it, you will only have the option of using the standard, mechanical (cable operated) SPEEDHUB versions.

Yeah, not as easy then.

Maybe some kind of signed cert that is needed, but mainly Pole just needs to greenlight a Bosch servicer to load the tweaked firmware to support the E-14, much like allowing changing the speed limiter on a 29er Voima to a mullet configuration. It would be a drag if Pole doesn't play along.

Some positive market development for @slickrock and others potentially considering electonic shifting for Rohloff Speedhub

Bearing in mind the Rohloff's less than satisfactory response above (at least for me) please watch the entire below video. It is in German , which I understand to certain degree but you could use the YT auto-translate function.

In my view this might be a very good alternative, especially if you do not need the total integration with Bosch power system. Whether this option would work for you is not for me to say but it is great that there would be an alternative to E14 system.

Enjoy!

Interesting product concept as I can say firsthand that electronic Rohloff shifting is bees knees and levels up e-shifting thats now common on derailleur systems. That said, Rohloff should come out a product like this themselves. Also, what's absent here is the dynamics provided by the Bosh motor itself which slightly overruns and delays shifting when rider pedal input is at the top/bottom stroke - the very thing that gave the "integrated feel" I mentioned previusly.

 

[slickrock]

OK, I got a parts list from the Rohloff distributor in the U.S. that handles non-OEM E-14 bike integrations. On can feel goosed enough pricewise with just converting a bike to use a Rohloff hub, but adding electronic shifting adds to the sticker shock (R&M and Nicolai must get some heavy discounts it seems). it would make sense to first see if I can get the Sonni integrated first with belt drive tensioner and hub itself before committing to an E-14 setup. While I omitted the prices to the parts list below (you can PM me if interested), I'm curious if any of you know a European (not necessarily Euro) Rohloff retailer where one could get favorable prices for Rohloff parts (In my case for Yanks like me since the U.S Dollar is strong, and also can take advantage of VAT tax discounts ).

1. Rohloff Speedhub 32-hole A12 DB PM, black-8097PM-300268 [Thru-axle version of the hub need for the Pole. Technically this is not an E-14 specific part] Note: Rohloff 32-hole A12 DB PM, black-8097PM-(,8097PM,8097PM,,,,,)

2. Rohloff A12 PM Set (Art. #8558+8555) Axle-plate A12 PM + PM Bone*-8564-278430 [Technically this is not an E-14 part, rather it is needed to attach hub to rear post mount bikes that aren't built specifically for internal gear rear hubs. ] Note: Rohloff A12 PM Set (Art. #8558+8555) Axle-plate A12 PM + PM Bone*-8564-(,8564,8564,,,,,)

3. Rohloff E-14 DC/DC-CAN Converter-278418 [E-14 Specific part] Note: Rohloff E-14 DC/DC-CAN Converter-(,8802,8802,,,,,)

4. Rohloff E-14 Switch Unit (Shifter) 265834 [E-14 Specific part] Note: Rohloff E-14 Switch Unit (Shifter)-(,8801,8801,,,,,)

5. Rohloff E-14 DC/DC-Can Converter to Shifter Unit Cable 600 mm-8806- 299344 [E-14 Specific part] Note: Rohloff Rohloff E-14 DC/DC-Can Converter to Shifter Unit Cable 600 mm-8806-(,8810,8810,,,,,)

6. Rohloff E-14 Shifter Unit, E-Bike-278385 [E-14 Specific part] Note: Rohloff E-14 Shifter Unit, E-Bike-(,8803,8803,,,,,)

 

[tooFATtoRIDE]

Kindernay hub is out of contention. The company went bankrupt.

More info here (uncle Google translate should help here):

Konkurs for prestisjefull sykkel-startup med Peter Hermanrud og Dag Otto Lauritzen på eiersiden

CA Technology kaster inn håndkledet.

www.shifter.no

 

[slickrock]

OK, it's been awhile, but it's worth providing and update on the belt tensioner search. With some help from tooFattoRIDE, we were able to zero in on the OEM maker and version of the tensioner that they can provide for this project:

As it stands, it works with Bosch CX motor, but as seen in the wild could also be adapted to other motor setups. The transverse design really works to keep the tensioner out of the underside of the bike/motor where it would otherwise be more susceptible to damage, and the longer chainstay. Also, the mud clearance of the Sonni/Voima should easily accommodate this design, especially with the Sonni in it's naked motor configuration.

Problem is at the moment, this a an OEM B2B part and is not sold directly to consumers , and with a MOQ of 250. Social engineering would be required with Nicolai or one of it's retailers to get one ordered as a replacement part. It would be a lot easier of Pole, itself, could jump on board configuration, whether it be for an IGH with this project, or for and actual MGU.

 

[tooFATtoRIDE]

Welcome everyone and a Happy New Year 2024!

Indeed I have been on the case to somehow buy these.

For Voima, it would not be a straight fit. An adapter would have to be made. Since I do not have access to 3D printing or a professional machine shop, I guess the process would consist of (1) CAD (cardboard aided design) prototyping; (2) plywood or hard piece of plastic testing; (3) aluminium plate hand cutting, shaping and fit testing; and perhaps (4) designing something in some sort of CAD software. The final stage would be getting this laser cut.

However, since I do not have access to a professional shop, I am likely to stop at step 3. Good enough for me, though. One tiny issue here, I would need to have the tensioner in my hands, which proves to be a massive problem right now.

For your entertainment see below pictures of the stage 1 (CAD prototyping) of the Pinion belt tensioner in action (this would might end up being fitted to my belt driven Nicolai bike):



So far four prototypes



The Gates belt tensioner would be a more elegant solution but that is not happening for obvious reasons. Above all, it would be better protected between the frame and the wheel.

Any constructive feedback is welcomed.

 

[Onetime]

Looks good man! I look forward to seeing the finished product!

 

[slickrock]

Welcome everyone and a Happy New Year 2024!

Indeed I have been on the case to somehow buy these.

For Voima, it would not be a straight fit. An adapter would have to be made. Since I do not have access to 3D printing or a professional machine shop, I guess the process would consist of (1) CAD (cardboard aided design) prototyping; (2) plywood or hard piece of plastic testing; (3) aluminium plate hand cutting, shaping and fit testing; and perhaps (4) designing something in some sort of CAD software. The final stage would be getting this laser cut.

However, since I do not have access to a professional shop, I am likely to stop at step 3. Good enough for me, though. One tiny issue here, I would need to have the tensioner in my hands, which proves to be a massive problem right now.

For your entertainment see below pictures of the stage 1 (CAD prototyping) of the Pinion belt tensioner in action (this would might end up being fitted to my belt driven Nicolai bike):



So far four prototypes



The Gates belt tensioner would be a more elegant solution but that is not happening for obvious reasons. Above all, it would be better protected between the frame and the wheel.

Any constructive feedback is welcomed.

View attachment 132007 View attachment 132017

Kudos tooFat. Excellent progress which begs the following:

1. BT1 is an available tensioner that can be purchased now, unlike the Nicolai tensioner at the moment.
2. Arguably this tensioner might be better for the Voima than the Sonni, simply because it is not transverse mounted like the Nicolai, which, in my self-serving need to support the Sonni, has been what I've been pushing for thus far.
3. To me the biggest BT1 design flaw is it's undercarriage exposure, but that huge bash guard would definitely help!
4. So is #4 design that latest iteration of what is needed? That is only a single plate adapter is required?
5. The material you end up using might be dependent on getting your chainline aligned. Fo example hi-impact plastic could be used if it needs to be thick to counter a larger chainline difference. Or steel if the opposite is the case. Or aluminum if in between.

Keep dem updates coming.

 

[tooFATtoRIDE]

Kudos tooFat. Excellent progress which begs the following:

1. BT1 is an available tensioner that can be purchased now, unlike the Nicolai tensioner at the moment.
2. Arguably this tensioner might be better for the Voima than the Sonni, simply because it is not transverse mounted like the Nicolai, which, in my self-serving need to support the Sonni, has been what I've been pushing for thus far.
3. To me the biggest BT1 design flaw is it's undercarriage exposure, but that huge bash guard would definitely help!
4. So is #4 design that latest iteration of what is needed? That is only a single plate adapter is required?
5. The material you end up using might be dependent on getting your chainline aligned. Fo example hi-impact plastic could be used if it needs to be thick to counter a larger chainline difference. Or steel if the opposite is the case. Or aluminum if in between.

Keep dem updates coming.

Re 1: Indeed, this is why I could start prototyping. I have the tensioner and a bashguard in hand. Even from the stage when I was just visualising, having it in hand made some realisations. For example, I would have wanted it to sit closer to the engine axle but there is not room.

Re 2: The Gates tensioner would most likely be a better solution. If the adapter is well designed, it could be positioned right behind the frame, in front of the rear wheel. The exact coyld be achieved with the grass-roots type of engineering involving pieces of cardboard and plywood but it takes time as it is my first foray into this high-tech area

Re 3: In my view the tenstioner without the bashguard would end up smashed in no time, although I am rather careful with my riding in a rocky environment.

Re 4: Design No 4 is the latest based on cardboard. The next stage will be with a 5mm plywwod. The cardboard stage was just to have a basic shape. Unfortunately it lacks ridigity even though it is a thick piece of cardboard. Plywood should provide ridigity so that I could check what thickness would be required. I have three thicknesses available to me: 5, 7 and 10mm. This should help me with the alignment.

Re 5: The cheapest and easiest to work on without access to 3D printing is an aluminium sheet. These are available in a variety of thicknesses so it should help minimalise the use of shims to align the entire setup.

Once I have the template ready and the adapter cut-out, the first weeks/months the bike will be run as a single speed as this is how I could test it. The rear wheel hub things takes forever to organise so at least I will be able to test the belt length (have three belt option ready and waiting) and its tension, which appears to be crucial for longevity and performance of Gates belts.

I hope to start prototyping with plywood this weekend. Let's see how this goes.

 

[tooFATtoRIDE]

Prototyping continues. Not pretty or fancy, but should do at this stage.

 

[slickrock]

Prototyping continues. Not pretty or fancy, but should do at this stage.

View attachment 132777

View attachment 132778

View attachment 132779

Excellent progress. So how's the chainline looking with this piece of plywood?

BTW, what an cool idea to go single speed to get the tensioner mechanics worked out before committing to a internal gear hub setup. Even better, you could get a sense of what a single speed Voima would be like to ride. Or a 2-speed setup with something like Powershift if they had a single speed adapter available.

 

[tooFATtoRIDE]

Houston, we have a problem.

Today I have received the 122T belt. So far I have the following belts: 120T, 122T and 125T.

The problem I discovered is the chain growth:

• The 120T belt is too short. Nothing to add here.
• The 122T belt is slightly too long when the bike is unweighted. Yet it is too short when and no full wheel travel could be achieved.
• The 125T belt is too long when the bike is unweighted. It allows, however, the full wheel travel.

I suspect the chain growth is too great for the existing setup (Pinion BT1 chain tensioner, 39T front sprocket, 34T rear sprocket).

So far this is a bike stand-testing. Next week I will have my forks ready so once they are fitted, I will test the system with my own weight. I do not expect different results but I want to confirm it.

So, it is time for the collective brainstorming. What to do here? Any thought and/or suggestions?

 

[tooFATtoRIDE]

Potential solutions:



In both videos a full wheel travel was tested to see if (1) the belt's teeth do not touch at zero wheel travel; (2) the belt tensioner was still able to extend (squeeze the spring) at a full wheel travel; and (3) the belt was long enough at a full wheel travel.

Prototype 6 was ok-ish at test 1, and passed tests 2 and 3.
Prototype 7 passed all three tests.

I still need to test the belt tension with the Gates app.

Still nowhere near a working solution but that's just the nature of prototyping. The true difficulty will start when the shape and length of the tensioner arm established. At present time I have no idea on how to incorporate it into the existing belt tensioner.