Belt drive on a thru-axle Cruzbike

[bret]

I have a Q45. Some of this may apply to other models, but I don't have those. I also don't have this working now - I'm in the design stages.

The 2021 model has thru-axles, which is significant.

A belt must be released to change it, so a small reduction in the crank-axle distance must be possible, and then re-tensioned before use, and an eccentric bottom bracket permits that with no structural changes to the Q45. If we weld something on, we must then heat-treat the stays-and-bottom-bracket part again. But I don't see a need.

Am I missing something?

The issues I'm aware of now:

1. Selecting an appropriate eccentric bottom bracket.
2. Selecting an appropriate internal gear hub. Must work with thru-axle and anti-rotation mounting somehow (biggest problem).
3. Aligning the crank cog and the drive cog. Dependent on the internal gear hub selected.
4. Sizing the belt that fits the application.

Apart from solving the anti-rotation problem, this can probably be accomplished with off the shelf parts now. Hopefully that has a solution as well.

 

[bret]

The thru-axle issue limits the possible choices of internal gear hub. I am aware of only 2+ candidates now, and I may need to wait until more manufacturers provide an option as thru-axles (presumably) become more widespread.

The options now are:

1. NuVinci/Enviolo continuously variable hub
2. Kindernay hub (https://kindernay.com/)

The Kindernay is a near clone of the Rohloff hub with a few differences. One is that it was not designed before thru-axles, and works with them. The web site specifically mentions solutions for Gates Carbon belts, so it's promising.

I wrote '2+' above. The Rohloff hub does not work with thru-axles - it was designed before they came into use, and boring a 12mm hole through the centre will destroy the mechanism. Rohloff provides a set of adapters which screw into each side through a 12mm fork to mount the hub on thru-axle bicycles, but they won't sell it to you.

Instead, they require that a bicycle shop they approve of uses a measuring kit they provide to ensure that the adaptors fit the way they like (and can guarantee presumably). If they approve the result, they will sell the hub. Given the extra thickness of the two forks on a Cruzbike (fork and chainstays), I have my doubts, and it's not easy to answer the question.

Do you know of any other internal gear hubs which work with thru-axles?

 

[Rod Butler]

Do you know of any other internal gear hubs which work with thru-axles?[/QUOTE]



Ok, short answer to your question, No.
Although by putting a Rolhoff on an unapproved bike myself, I'm sure I have voided any warranty.
If that is ok with you, you can do whatever you like.

Secondly this guy will do exactly what he says in the title.
https://www.cyclingabout.com/carbon-belt-drive-everything-you-ever-need-to-know/

Thirdly (same guy) has some interesting things to say about Belt Tension.
Go to, about the 7th minute, although it's all worth watching.

But wait there's more. Eccentric bottom brackets. I used the https://www.trickstuff-shop.de/Excentric-bottom-bracket
for a long time, hoping to soon fit the Belt Drive to my S40 (sorry I can't comment on the Q45)
I eventually removed it as I decide to stay with the chain for now.

Removing the wheel with a Belt drive, on a IGH, on a FWD bike....In short a pain in the butt.
However.
Option (1) Gaadi tubes are fantastic https://gaadi.de/?page_id=3671 .....for fixing flats.
Option (2) Use a spring loaded tensioner. Lots of ideas for them around. You will Have to have a snubber though.
Option (3) Remove tension in the Belt (and/or remove the wheel) by removing/replacing the chain-wheel.
Very easy, think about it.
I found the video section on belt tension extremely interesting and I think that will mitigate some of your concerns.

Finally I'm not sure that through axles are the be-all-and-end-all unless you have very specific requirements that demand them.
I will eventually put a Belt Drive on my S40 but at the moment a waxed chain and a spring loaded tensioner are maintenance free.
I use a chain runner when I tour. https://www.chainrunner.de/

Can I ask for you indulgence for a couple of other observation.?

The advantage of a chain with an IGH is that you can change the chain-wheel to get a whole different set of ratios.
You can even carry it with you when touring different terrain. I've done it. Not so (as easily) with a Belt Drive.

If you are determined to fit a Belt Drive, get the ratios you need, well and truly established with the chain set up
that is available in the Belt Drive set up that you anticipate fitting.

Phew! ....that was longer than I thought it was going to be, I hope it helped. I have some other posts that may be of assistance.

 

[bret]

I hope it helped

Thanks. I'll read/view through that information. I gather you used a Rohloff hub?

I'm not in a hurry on this, as I'm putting a motor on my Q45, and I haven't chosen an internal gear hub yet - both are expensive so I will watch and consider for a bit. I particularly don't have much choice on the thru-axles as my Q45 has them.

I saw that chainrunner on another model of the my folding commuter bike. As you use it touring, I'd like to hear more of your experience. Does it help riding in rain? What other observations do you have about it? I had a waxed chain on my Q* and I liked it.

(Q* - I'm not quite sure what it was. I traded JT a Silvio for it out of his collection, and he said it was a near-production model of the first Q, but it might also have been something of a mongrel. He made sure it was all in good working order for the trade.)

 

[McWheels]

I'm going to go out on a bit of a distraction here, but it might end up being relevant. A chap on this forum @Tortue has spent the time to invent a rain fairing.
Thread here

In fact I may be asking for his 3D printer files shortly.

 

[Black Hawk Down]

The thru-axle issue limits the possible choices of internal gear hub. I am aware of only 2+ candidates now, and I may need to wait until more manufacturers provide an option as thru-axles (presumably) become more widespread.

The options now are:

1. NuVinci/Enviolo continuously variable hub
2. Kindernay hub (https://kindernay.com/)

The Kindernay is a near clone of the Rohloff hub with a few differences. One is that it was not designed before thru-axles, and works with them. The web site specifically mentions solutions for Gates Carbon belts, so it's promising.

I wrote '2+' above. The Rohloff hub does not work with thru-axles - it was designed before they came into use, and boring a 12mm hole through the centre will destroy the mechanism. Rohloff provides a set of adapters which screw into each side through a 12mm fork to mount the hub on thru-axle bicycles, but they won't sell it to you.

Instead, they require that a bicycle shop they approve of uses a measuring kit they provide to ensure that the adaptors fit the way they like (and can guarantee presumably). If they approve the result, they will sell the hub. Given the extra thickness of the two forks on a Cruzbike (fork and chainstays), I have my doubts, and it's not easy to answer the question.

Do you know of any other internal gear hubs which work with thru-axles?

Kindernay went out of business.

 

[Black Hawk Down]

I am currently working with a LBS and Rohloff to fit the speedhub to my Q45. The jury is still out. I'll come back and report my experience once it's complete.

Edit: for the record, it won't be cheap. The current estimate is about $2200 - $2400.

 

[LarryOz]

Edit: for the record, it won't be cheap. The current estimate is about $2200 - $2400.

wow - hardly seems worth that huge cost!

 

[Black Hawk Down]

wow - hardly seems worth that huge cost!

I'm in a situation where neither SRAM nor Shimano drive trains work properly on my Q45. I'm at wits end. I don't have these problems using the exact same drive trains on either my S40 or V20. This is my last hope to get something working before my long tour. I'm willing to pay almost anything to be able to use the Q45. On my last long tour I used my S40 and suffered with recumbutt the whole way. I don't have that issue with the Q45. It's the most comfortable bike I have ever owned. The Speedhub will give me the gear range I need and there should be no issues with the drive train. Rohloff is well known for reliability and quality. But, I still don't know for sure that it will work on my Q45. I'm on pins and needles.

 

[Animal494]

Look forward to hearing how it goes, BHD! What do you have planned for your next tour?

 

[Black Hawk Down]

Look forward to hearing how it goes, BHD! What do you have planned for your next tour?

Deadhorse, AK to Ushuaia, AR. Starting Jun 15, 2025.

 

[Animal494]

Deadhorse, AK to Ushuaia, AR. Starting Jun 15, 2025.

Wow!!

 

[Mathew Fy]

Deadhorse, AK to Ushuaia, AR. Starting Jun 15, 2025.

To feed your head with ideas, check out fellow Cruzbiker David Byrne's (not the Talking Heads singer) exploits.

https://www.crazyguyonabike.com/doc/?o=3d2&doc_id=14827&v=3Rl

David and Julie Byrne Finish World Tour on Their Cruzbikes

July 17, 2011/ Maria Parker I was so inspired by the following press release sent to us by David Byrne’s family, I wanted to share it with you.Finishing World Tour Saturday at Noon!Ordinary people can do extraordinary things. After cycling around the world for the 2nd time, Amery Wisconsin...

cruzbike.com

Mississippi River Trail, by David Byrne

Lake Itasca to St Paul in August

www.crazyguyonabike.com

 

[Black Hawk Down]

To feed your head with ideas, check out fellow Cruzbiker David Byrne's (not the Talking Heads singer) exploits.

https://www.crazyguyonabike.com/doc/?o=3d2&doc_id=14827&v=3Rl

David and Julie Byrne Finish World Tour on Their Cruzbikes

July 17, 2011/ Maria Parker I was so inspired by the following press release sent to us by David Byrne’s family, I wanted to share it with you.Finishing World Tour Saturday at Noon!Ordinary people can do extraordinary things. After cycling around the world for the 2nd time, Amery Wisconsin...

cruzbike.com

Mississippi River Trail, by David Byrne

Lake Itasca to St Paul in August

www.crazyguyonabike.com

Thanks. He's a fellow Wisconsinite. I do plan on continuing my touring to Europe, Australia, New Zeeland, and various places in Asia after my tour of the Americas, but I'll be taking breaks in between. I have no immediate plans to tour Africa or the middle east. I'm retired. What else is there to do?

 

[Black Hawk Down]

Do you know of any other internal gear hubs which work with thru-axles?

@Brett

@Rod Butler "Ok, short answer to your question, No."

Actually, they do have a thru-axle kit. The hubs are not thru-axle but they can use fixtures to clamp to thru-axle bikes. I'm having my Q45 converted to a Rohloff speed hub currently. The derailleur hanger had to be modified as it was too thick, but so far, that's it. I will also need a chain tensioner and a special shifter for the Q45 handle bars. Initially, I've decided not to use a belt but I may change that later.

Bill

 

[Flying Dutchman]

@Brett

@Rod Butler "Ok, short answer to your question, No."

Actually, they do have a thru-axle kit. The hubs are not thru-axle but they can use fixtures to clamp to thru-axle bikes. I'm having my Q45 converted to a Rohloff speed hub currently. The derailleur hanger had to be modified as it was too thick, but so far, that's it. I will also need a chain tensioner and a special shifter for the Q45 handle bars. Initially, I've decided not to use a belt but I may change that later.

Bill

So glad you finally got your Q45 sorted after all your tribulations with the different derailleur troubles. Safe travels, hope you will have a great time.

 

[Black Hawk Down]

So glad you finally got your Q45 sorted after all your tribulations with the different derailleur troubles. Safe travels, hope you will have a great time.

Thanks, but I wouldn't say I'm out of the woods yet. Until I have the bike with the Speed Hub and it's working fine, I'm not calling it a win.

 

[Veresia]

You're on the right track with the eccentric bottom bracket—it'll save you from needing to weld. The anti-rotation problem with the thru-axle is definitely tricky, but I’ve had good luck with hubs like the Rohloff that come with adapters for thru-axles and use torque arms to handle that. For belt sizing, I’ve used Gates' calculators in the past, and they worked well for me. As for crank and drive cog alignment, it’s a bit of a pain, but getting CAD specs from your hub manufacturer could help dial it in.

 

[Black Hawk Down]

You're on the right track with the eccentric bottom bracket—it'll save you from needing to weld. The anti-rotation problem with the thru-axle is definitely tricky, but I’ve had good luck with hubs like the Rohloff that come with adapters for thru-axles and use torque arms to handle that. For belt sizing, I’ve used Gates' calculators in the past, and they worked well for me. As for crank and drive cog alignment, it’s a bit of a pain, but getting CAD specs from your hub manufacturer could help dial it in.

I won't be using a belt.