Gates Carbon Drive + Geared Hub

[georgec]

Thanks for the comments...

John, You are no doubt right right. But it does seem to me that a creative tensioning scheme could work and not adversly affect belt durability (not that I want to go that way... as I feel that an adjustable dropout would be quieter and more reliable).

Andrew, are the forward components actually available anywhere? When I look for them all I find is a dead web site and old postings.

 

[Andrew 1973]

Philcentric Bottom Bracket

How about a Phil Wood Philcentric BB instead? I didn't realize that the Forward Components ones were no longer available. It looks like Phil's version is still out there.

 

[Andrew 1973]

...or this...

http://www.trickstuff.de

alt="Exzentriker"

 

[Andrew 1973]

On second thought...

Both require proprietary tools, but the Phil one is available to shops ONLY and is bound to be crazy-expensive. The Trickstuff BB tool is available to anyone and costs just 16.50 EUR.

That said, unless my LBS had the Phil tool (which they likely won't) I'd skip the Phil Wood idea.

It is said that these BBs offer minimal adjustment and depending on chainstay length and gearing, a half-link might be needed. This may or may not be a solution for the Gates belt; it depends on how close you can get the fit witout an eccentric. At least you can always deal with chain drive or fabricate the custom dropouts you need. I'm interested in seeing what the final solution will be.

 

[georgec]

Update... 5 months in

I have been riding this setup now for 5 months. I still like it for all the reasons stated earlier.

My interest in belt drive has waned, since the straight chain drive is working so well for me.

I may still make the custom dropouts, because it would be nice to have a way to adjust the chain tension, and I still have some interest in trying out the belt drive.

But then again, the chain has only jumped off twice that I can remember, so maybe it's not worth the effort. And since I have only touched the chain twice, my fixation on chain grease has abated.

I have found the Nexus 8 to be very pleasant to ride and zero trouble. The jtek bar end shifter is awesome, especially after I made a rubber ball of 3M linerless splicing tape on the flipper to protect myself from being impaled and to make it easier to shift with the heel of my hand. I have considered cutting the end of the handle bar off to bring the shifter more under my grip.

I do feel like I could use an extra cog both above and below, so I might get a second front wheel with an Alfine 11 hub. And it is always a good idea to have a spare front wheel, right? Maybe the 11 would be the summer wheel, and the 8 would be the mud season wheel.

Otherwise, it is hard to think of any other change to make. Maybe I'll pimp the crank & pedals in the spring.

 

[Romagjack]

Great looking machine George.

Great looking machine George. Please keep us updated. Now you need to figure out how to add disc brakes. You could start a business and offer a Cruzbike mod package for us non-gear heads that prefer the "Cruz" in Cruzbike over the derailer versions.

 

[baov]

Now that the sofrider has

Now that the sofrider has eliminated the front suspension, we could easely add belt drive with an eccentric bottom bracket. I thought of doing it myself too, but the price right now would be a couple of hundreds more than a chain drive and i'm kinda strapped on cash. Perhaps one day.

Has anyone ever done it yet?

EDIT: Nevermind, you need an enlarged bottom bracket shell to fit the eccentric, and then into which you fit a bottom bracket.
Then again, all we need to do to tension the belt is adjust the boom length, then position the seat to fit your legs.

 

[nilfaith]

Where are all the pictures? Seem s cruz bike is allergic to having in hub gears on a cruzbike. Which is a pity because its the only option I am not negotiable on.

 

[McWheels]

It's fine on a Softrider, or V2k. That's a Sturmey-Archer 8Sp with disk brake. Ticking over the miles on the commute each day quite happily.

View media item 206View media item 198View media item 196

 

[Robert Holler]

A bolt on hub will work on the T50 and OLDER Q's and Sofriders. The Q45/S40/S30/V series bikes are not compatible with bolt on hubs - but a QR Rolloff would be fine on that front end if you use the "Monkey Bone" disc brake I.S. adapter adapter they sell to secure the hub.

The only current model I see that making sense on is a Q45 and maybe an S40.

 

[Rod Butler]

Nexus 8 hub is in the bike and works great!

Some details:

Shaved 2mm off of the hub's dust cover nut so that the hub fits in the 130mm fork clearance. Ground down the Nexus no-turn washers to fit between the fork and dropouts. Modified the dropouts by boring to accommodate the 3/8" axle and cutting a relief for the axle nuts in each outer surfaces. Set up for now with Biopace 42 chainring, 20 cog, & chain made up neat.

Lovin the bike. Commuting to work. I am one very happy camper!

BTW: chain grease is already on my pants, so stay tuned for the belt drive dropout mods when the snow is falling.

Many thanks for all the helpful comments.

I have a Rolhoff on my S40 with an excentricker Eccentric Bottom Bracket working flawlessly over loaded/camping tours of France, England, Scotland, Wales & Ireland in the last 18 months.

But the best piece of kit to go with it (and which may suit you on your IGH set up) is the 'chainrunner'
http://chainrunner.de/index_en.html. Also available on Amazon or Ebay

You can have the chain waxed (as I have) or otherwise and with the chainrunner installed...No grease anywhere & low maintenance.

I too had visions of the Belt Drive with the IGH (hence the EBB) but the waxed chain & chainrunner works so well that the other plans are on hold.
In any event, it may serve as a practical working solution for you in the mean time.

As far as the Belt Drive is concerned (for any S40 readers) the chainstay length is crucial as the EBB only gives about 3mm in either direction and there are no other adjustment solutions ....Do Not rely on the specs, Check Measure Your Own Bike...

From memory, mine is 483mm which would have required a F50t R24t and a 125mm belt. (In one config. A ratio of 2.08.)
It's worth remembering that the Belt Drive will limit you desire to change ratios with the IGH, which would otherwise be achieved quickly and cheaply by changing either the rear sprocket or chain ring.
If you are still determined after perhaps trying the chainrunner, I would suggest trying out the proposed belt configuration on a chain set up to see if that ratio suits your needs.

 

[elg]

***************
NOTE: By mistake, I first emailed this directly to Cruzbike instead of posting to the forum. Doug Burton provided a very helpful response, which I have attached below, with his permission.
***************

Date: Thursday, July 12, 2012, 3:47 PM

I would like to buy a Softrider or Silvio for commuting and weekend riding. These look like bikes that will be fun to ride for a long time. But I hate chain/shifter/grease/mess/on frame and pants. I have read stories of the MBB making love to the rider's leg, which I can easily visualize it doing to my leg. I also understand that these parts run cleaner on a Cruzbike... Really! But... they are still greasy, right?

So... I would like to put a carbon belt drive / IGH (internally geared hub) on the Softrider or Silvio. When I look around the forums, I see a fair bit of angst around this idea. But I am a handy engineer with access to a good machine shop and willing to void my warranty, at least on certain parts.

As far as I can tell from the forums, the key question is how you tension the belt.

Here are a few scenarios I would like to suggest:

A) Silvio: Modify the joint between the BB and carbon stay to allow adjustment of overall length. It looks like the stay has a bead that locks into a slot on the BB. The most primitive approach I can think of is to grind (ouch!) the bead off and put a tapered shim in above it. This leaves bolt pressure alone to secure the stay to the bottom bracket.

B) Softrider: Cut the front stay forks on each side a few inches from the hub end. Thread the parts internally with right hand threads toward the bottom bracket and left hand threads toward the hub. Make a matching contra-threaded insert that allows overall stay length to be adjusted independently on each side. This makes each side of the stay into a sort of turnbuckle.

C) Silvio: Replace the carbon stay with a custom part that allows adjustment in length on both sides. Perhaps with turnbuckle action along the lines described in B) In each case, the fork needs to absorb the torque produced by the hub. Is this a big deal (provided that I attach the hub to the fork without weakening the fork)?

I am interested in any reactions/suggestions folks might have. Also, I welcome comments on which IGH might work best in each approach.

Thanks,
George

***************
UPDATE: I am most interested in doing this on the Silvio, so I have posted here. But I left the softrider related comments the original emails.
***************

From: Douglas Burton
Sent: Thursday, July 12, 2012 11:30 PM

Hello, George,

The Silvio isn't adaptable to any IGH that I am aware of. The following issues present:

1. The Silvio fork uses 130mm dropout spacing, and that dimension is on the tight side to aid front triangle rigidity. The fork won't spread to the 135mm spacing used on IG hubs happily, if at all. The 130mm dimension carries further to the carboyoke and outer carboyoke attachment parts, and these can't be spread at all.

2. The outer dropouts, that connect the carboyoke to the fork dropouts, are very wide, again for rigidity. The quick release, for example, is 170mm long instead of the usual 141-146mm. The IG hubs with which I am familiar use 182mm axles, and these are integral to the internal drivetrain and can't be switched out for longer ones. Thus there's insufficient axle length for the axle nuts to properly grab, and the outer dropouts would have to be through-drilled to pass the axle, not to mention there's no remaining clearance for the shifter unit.

The Sofrider will accept an IG hub if a tensioner is fitted.

We have no experience with belt drives, but haven't had any complaints about chainring tattoos as the chain falls quickly away to the lower side, rather than following the frame as with a conventional RWD recumbent.

We can't recommend modifying the forks and front end components. The rounded section of the Silvio carboyoke serves to positively locate the components fore-aft and rotationally, and they prevent fretting of the carbon fiber by the attaching brackets at the bottom bracket. Removing these will allow the carboyoke to move relative to the bottom bracket and likely cause eventual failure of the part.

Hope this helps.

Best,

Doug

 

[elg]

Speaking of chains that "fall quickly away", my sofrider has sat for years because I could never solve the problem of the chain falling off. I emailed Doug about it years ago and his reply was essentially that it shouldn't happen. I agree with that completely, but having nearly died in traffic because my chain fell off I am quite convinced that it does. I think that an IGH would go a long way toward solving the problem, and a belt drive would certainly put an end to it. Sadly Cruzbike has never taken seriously the longstanding customer requests for a belt drive and IGH. I guess the customer is not always right.

 

[benphyr]

I too hope that one day have I can have the perfect low maintenance commuter Cruzbike with internal gearing and belt drive.

However, recumbents are a niche market. Within recumbents internal hub gearing would be some smaller portion. So the potential market is unlikely be large enough to warrant production of another model or option for a Cruzbike with internal hub gearing.

Additionally, initial cost of an IGH is more expensive so either your profit margin decreases or your price is significantly higher than a “base” model - likely both. Neither option helps to attract more sales. And neither option is likely to be chosen by someone wanting to try out a Cruzbike.

When the customer is right the tough decisions remain to be made by the business to keep the business running.

 

[elg]

I too hope that one day have I can have the perfect low maintenance commuter Cruzbike with internal gearing and belt drive.

However, recumbents are a niche market. Within recumbents internal hub gearing would be some smaller portion. So the potential market is unlikely be large enough to warrant production of another model or option for a Cruzbike with internal hub gearing.

Additionally, initial cost of an IGH is more expensive so either your profit margin decreases or your price is significantly higher than a “base” model - likely both. Neither option helps to attract more sales. And neither option is likely to be chosen by someone wanting to try out a Cruzbike.

When the customer is right the tough decisions remain to be made by the business to keep the business running.

A properly designed front triangle could work for either derailluer or IGH. If sourcing parts for a belt/IGH model was not practical from a business standpoint then the frame could be offered w/o components for a user build. The most frustrating thing is that they seem to persist in designing the front triange to NOT support belt drive, which has driven people in this forum to go as far as welding their own frames.

 

[elg]

I have a Rolhoff on my S40 with an excentricker Eccentric Bottom Bracket working flawlessly over loaded/camping tours of France, England, Scotland, Wales & Ireland in the last 18 months.

But the best piece of kit to go with it (and which may suit you on your IGH set up) is the 'chainrunner'
http://chainrunner.de/index_en.html. Also available on Amazon or Ebay

You can have the chain waxed (as I have) or otherwise and with the chainrunner installed...No grease anywhere & low maintenance.

I too had visions of the Belt Drive with the IGH (hence the EBB) but the waxed chain & chainrunner works so well that the other plans are on hold.
In any event, it may serve as a practical working solution for you in the mean time.

As far as the Belt Drive is concerned (for any S40 readers) the chainstay length is crucial as the EBB only gives about 3mm in either direction and there are no other adjustment solutions ....Do Not rely on the specs, Check Measure Your Own Bike...

From memory, mine is 483mm which would have required a F50t R24t and a 125mm belt. (In one config. A ratio of 2.08.)
It's worth remembering that the Belt Drive will limit you desire to change ratios with the IGH, which would otherwise be achieved quickly and cheaply by changing either the rear sprocket or chain ring.
If you are still determined after perhaps trying the chainrunner, I would suggest trying out the proposed belt configuration on a chain set up to see if that ratio suits your needs.

I'm getting inspired by your post to look at reviving my Sofrider by replacing the derailleurs with an IGH setup like yours. The one question I have is whether the front suspension and slight excentricity when the front triangle is adjusted will play hell with the chain when there is no rear derailleur to tension it. I would really appreciate any wisdom you can share from your experience and any specs, pics, etc. of your rig. I enjoyed riding my sofrider when the chain would stay on.

 

[Rod Butler]

I'm getting inspired by your post to look at reviving my Sofrider by replacing the derailleurs with an IGH setup like yours. The one question I have is whether the front suspension and slight excentricity when the front triangle is adjusted will play hell with the chain when there is no rear derailleur to tension it. I would really appreciate any wisdom you can share from your experience and any specs, pics, etc. of your rig. I enjoyed riding my sofrider when the chain would stay on.

Hi Elg, I did have the eccentric bottom bracket fitted because I eventually wanted to fit a Gates Carbon Belt as well.
If I revisit that fantasy I will reinstall it. I Highly recommend watching.....
https://www.cyclingabout.com/carbon-belt-drive-everything-you-ever-need-to-know/
Mmmm......I'm thinking, a spring loaded belt tensioner (and snubber) might be a better option if I revisit that idea.

I have refitted the original shimano hollowtech BB and am still using a chain for the following reasons.
1. Getting the EBB squared in the BB on both sides was not impossible but tricky. The Hollowtech is very straight forward.
2. I have fitted a spring loaded chain tensioner which works perfectly in the same role.
3. This chain tensioner also allows me to change chain-rings for various conditions. Not possible with a belt drive.
3. I wax my chain so I have even dispensed with the chain runner (https://chainrunner.de/) at least when I'm not touring.
4. If you are going to fit an IGH I highly recommend Gaadi tubes (https://gaadi.de/?page_id=3671) to make fixing flats easier.
5. I can't imagine your front suspension being affected by a EBB any more than a spring loaded chain tensioner (?) but I know nothing of SofRiders.
6. Absolutely crucial is the precision of the Chain Line, between chain-ring, tensioner and sprocket, but you know that.
7. If you decide on a Rolhoff, the handle bar shifter is a narrow fit and you will need the Soma Gator handlebars to fit it properly. It's a bit of a hassle but WELL worth it. (https://www.somafab.com/archives/product/gator-handlebar) Check one of my past posts on this.
I have a few other posts on these rambling, some of them may also be of use to you. Let me know how it goes.
R

 

[elg]

Hi Elg, I did have the eccentric bottom bracket fitted because I eventually wanted to fit a Gates Carbon Belt as well.
If I revisit that fantasy I will reinstall it. I Highly recommend watching.....
https://www.cyclingabout.com/carbon-belt-drive-everything-you-ever-need-to-know/
Mmmm......I'm thinking, a spring loaded belt tensioner (and snubber) might be a better option if I revisit that idea.

I have refitted the original shimano hollowtech BB and am still using a chain for the following reasons.
1. Getting the EBB squared in the BB on both sides was not impossible but tricky. The Hollowtech is very straight forward.
2. I have fitted a spring loaded chain tensioner which works perfectly in the same role.
3. This chain tensioner also allows me to change chain-rings for various conditions. Not possible with a belt drive.
3. I wax my chain so I have even dispensed with the chain runner (https://chainrunner.de/) at least when I'm not touring.
4. If you are going to fit an IGH I highly recommend Gaadi tubes (https://gaadi.de/?page_id=3671) to make fixing flats easier.
5. I can't imagine your front suspension being affected by a EBB any more than a spring loaded chain tensioner (?) but I know nothing of SofRiders.
6. Absolutely crucial is the precision of the Chain Line, between chain-ring, tensioner and sprocket, but you know that.
7. If you decide on a Rolhoff, the handle bar shifter is a narrow fit and you will need the Soma Gator handlebars to fit it properly. It's a bit of a hassle but WELL worth it. (https://www.somafab.com/archives/product/gator-handlebar) Check one of my past posts on this.
I have a few other posts on these rambling, some of them may also be of use to you. Let me know how it goes.
R
View attachment 11583

Rod,

Thank you so much for your reply and for all the great info. Your approach seems very practical. It gets me what is probably the most important thing, a simple chain connection between pedals and wheel that won't fall off. The many details you list, such as tubes and handlebars, go beyond what I'd even thought about. I see that you've also got disk brakes, which is another thing on my wishlist.

My concern about the front suspension was really for the chain. I wasn't aware of the tensioner you used and I was thinking about the issue with belt drive that's caused by the small changes in the distance between the chainring and sprocket caused by both leg length adjustment and the suspension. I'm not clear on why a belt tensioner couldn't work the same way, but since your solution of the waxed chainrunner seems very nice I'll focus on that.

I'm going to study your posts and the other info that you linked and start accumulating the components.

Thanks again,

Ed