# Q on cargo bikes & 1x11, 1x12 transmissions



## awai04 (Jul 29, 2004)

Q for anybody who has tried or considered: In terms of reliability, chain/cassette longevity and range, how well do 1x transmissions work with a cargo bike? I've heard that 3x9 or 2x10 transmissions are well-paired with a cargo bike, since such bikes typically are pretty heavy and designed for hauling stuff. The wider range then becomes helpful and replacement parts are less costly. That said, the parts I already have available to build the transmission are 11 speed. I've read that 11 speed chains can be made just as strong if not stronger than its 9 and 10 speed predecessors. So... can a 11-speed 1x transmission be just fine for a cargo bike? Fyi, intended use for this bike is primarily to ride up and down fire roads with the little one in a child seat; when she gets a little older, she'll be able to sit on the back. The other main use will be local commutes across the neighborhood on/off road. ...Thanks!


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## Bizman (Oct 11, 2010)

Well, from my limited experience since having less than 200 miles on mine (1st cargo bike) it may/will depend on several factors. If you have mostly flat ground a 1 x 11/12 system would most likely be fine, and even for some hills with the "proper" front chain ring! I tried a 30t first, it had plenty of torque, just not the speed I wanted. You will need to also take into consideration how much weight you will need to carry on those hills. 

Another consideration is how big of tires you would use? I wanted 3" tires for the comfort factor and some (not real aggressive) knobbys for riding back roads and riding main roads to get to the back roads (settled on WTB Rangers). I have no plans to use this bike for singletrack. I first tried a 1 x 11/46 but in the lowest gear (or 2) the chain would rub the tire. I was told that a 1 x 10/42 may not do this, well it did, but only in the lowest gear. I could have went to smaller tires (that would probably have worked) but didn't want those.

I ended up keeping the 1 x 10/42 and used a 42t chainring. Since my bike has the Bafang BBSHD e motor, I figured I never used a 42t low gear in my life and thought I could do without it (since I had a motor). I set the rear lower limit of the cassette to stop at the 36t and run it as a 1x9. This bike is so comfortable and moves along really well on the level and down hills, on most all hills I make it up without the motor, I just go slower!

If I am hauling a big grocery order/produce or gas stove, small cooler, food & water for my wife and I to cook out in the mountains along the road I will use the motor some on the hills to help with the weight. The later is a dream we had to do together on our bikes, I built her a non cargo e bike, it doesn't get any better than this! The motor works great when I need it but try to not use it more than I absolutely have to. She uses hers more!

If you do not want to put a motor on your bike (and watch your tire size) I think a 1 x 11/12 setup should work fine for most things you will tackle. You will have to decide what kind of weight you will carry and what kind of speed you will want to go, hence the decision on your front chain ring? I wish you the best and I am sure the time you and your child will spend tougher on those rides will bring wonderful memories, have fun!


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## awai04 (Jul 29, 2004)

Thank you for the detailed reply, Bizman! Yes indeed, I am looking forward to the times we will have on this bike I have in mind. I imagine they will be different from the single track focus I had a decade ago, but do welcome the change. 

Your thought on anticipated weight is a good one. Since the cargo bike is a format that will be new to me also (all previous bikes have been XC-trail bikes of various vintage, geometry, wheel size and tire width), sounds like I should leave some flexibility in the build to accommodate whatever I think I may end up doing with the bike. Right now, I do plan on climbing some decent hills we have here in the general area (bay area - Marin headlands or Mt Tamalpais would be perfect scenic venues), though don't plan on carrying too much gear other than what we will need to be comfortable for the day. I also am not planning to ride singletrack with the bike, though the thought to try does/will occur, lol. 

Curious I am to know: What chain line are you running on your cargo bike? Like you, I plan on running fatter tires (26 x 4" wide fat tires, actually, with a 177mm rear hub if I follow through with my current design plan). Given the long chain stays of a cargo bike, the chain-rear tire relationship changes slightly. Do I need to consider chain-tire contact issues that wouldn't occur if the chain stays are trail bike length?


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## Bizman (Oct 11, 2010)

I also have/and ride many other bikes, this was my first cargo bike and am very happy with it! Please explain when you say "what chain line are you running on your cargo bike" to help me understand your question? I am running 29+ 3" tires. You will have to watch how much offset your chain ring/bottom bracket and to get it aligned properly, I used spacers.

I tried to get my chain ring set so it was closest to the middle cassette sprocket as possible. For me it was the wide tires being the problem for the chain hitting the tire. Also I forgot to mention that I used the Xtracycle LEAP extension converting a Jones bike to a cargo bike. It says in the LEAP installation instructions that a 1 x 11 may hit the rear tire if you run to big of tires, they were right! Mine is 135 mm spacing.

On my wife's bike she is using a 1 x 11 and has no tire issues with the chain in the lowest gear. She is using the same tires and wheels (WTB Arch 45's) as I do. I think it has to do with the angle of the LEAP. You may well be able to get away with using a 30t and get a good chain line, it was not an option for us using the Bafang motor as to much offset was created by the motor.

We both use 42t chain rings mine with 25 mm offset and 3.3 mm chain ring spacer and 7mm motor spacers, and 20 mm chain ring offset for hers with 4 mm motor spacing, no chain ring spacers to bring the chain line to the center of the rear cassette. Here are the bikes to give an idea.

My bike:








Her bike:


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## awai04 (Jul 29, 2004)

Dang - those are some "plus" tires haha! Must be fun rolling over practically everything.

By chain line, I mean the distance as measured from the middle of the bottom bracket to the front chainring. A wider chain line accommodates a wider tire, all else the same. Though with a wider chain line is required a more laterally positioned cassette. The setup usually is accomplished with a wider hub, and also is possible with an offset narrower hub (e.g. Surly Pugsley - the frame uses an offset 135mm hub vs. the symmetric 170mm equivalent). 

What I suspect to be true but need confirmation is this: Say you have a fat tire that just barely clears the chain in the largest rear cassette cog when it's neatly tucked right behind the seat tube. As the chainstay lengthens and the wheel moves further way from the seat tube, the angle formed by the chain (as viewed from above) and wheel path rolling forward gets smaller, and the tire sidewall gets closer to the chain. Now, does this change in tire-chain relationship make enough of a difference between the chainstay lengths of trail and cargo bikes? That's the answer I seek. That said, I've since come to the conclusion that the answer probably depends on the particular setup, so maybe I'll just have to commit to some experimentation for that part.


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## Bizman (Oct 11, 2010)

Yeah, I wanted the big tires for the comfort, riding on back roads & the cool factor, I really haven't went over anything to technical, logs, big rocks, etc, just mountain/main roads. Although some were pretty washed out. Run the tire pressure around 12 and they go right over the stuff 

Thanks for you explanation about chain line! When I used the 30t chainring I had a wide chain line. The gearing worked good in the mid-upper range of the cassette but there was to much cross chaining going on to use the lower gears without a lot of noise from the chain. Actually my bike still rubbed the tire in the 2 lowest gears, my wife's did not but it made allot of noise in the lowest gears. This is why I ended up using the 42t chainring with the extra offset to get the chain more in line with lowest gears.

Your question:
As the chainstay lengthens and the wheel moves further way from the seat tube, the angle formed by the chain (as viewed from above) and wheel path rolling forward gets smaller, and the tire sidewall gets closer to the chain. Now, does this change in tire-chain relationship make enough of a difference between the chainstay lengths of trail and cargo bikes? That's the answer I seek.

My answer:
I think this is the case you reference and I think Xtracycle knows this as they say a 1x11 may rub if the tire is to big. With my wife's bike the tires do not rub, and she has an 11 sp cassette. I had to do some experimentation to figure it out. I think that's what you will need to do as well, just keep the size of tires in mind you will use. The other thing I thought about doing was to go with and IGH, then the chain line would have stayed consistent.


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## awai04 (Jul 29, 2004)

No problem and thanks also for sharing what you know! With your input I looked further and came across another thread about Surly's Big Fat Dummy. One link more and I was led to Surly's site itself:

Introducing Big Fat Dummy | Blog | Surly Bikes

...Sounds like we are correct about the chain line and tire size relationship.


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## Bizman (Oct 11, 2010)

Thanks awai04 for the link to the BFD! I had looked at that bike when I was deciding what to do when getting a cargo bike, somehow missed all that info about the chain/tire clearance. It does agree with what I was up against with my chain/tire clearance issues. Really for me even if it didn't have a motor (then it would be 24 lbs lighter), still, I could pedal it easily enough as it just floats along using the 3" tires, 42t chainring, and a 36t cog as the lowest gear. Good luck with your build!


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## 1x1_Speed_Craig (Jan 14, 2004)

awai04 said:


> No problem and thanks also for sharing what you know! With your input I looked further and came across another thread about Surly's Big Fat Dummy. One link more and I was led to Surly's site itself:
> 
> Introducing Big Fat Dummy | Blog | Surly Bikes
> 
> ...Sounds like we are correct about the chain line and tire size relationship.


I utilized this Surly link, this Surly drivetrain chart, and this one from RaceFace a lot when planning the build for my Big Fat Dummy frameset.

I chose a SRAM GX 1x11 drivetrain for use with my 3.8" Surly Nate tires. With the intended 76mm chainline on the BFD, I ended up going with the RaceFace Turbine Cinch 170mm cranks and a flipped 30T chainring for a 75mm chainline, and 213mm Q-factor. It shifts beautifully, and the gear range is plenty adequate for me in Michigan. I'm used to riding single speeds and fixed gears, so I now have 10 speeds more than I'm used to. 

Craig


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## awai04 (Jul 29, 2004)

Thanks for the Surly chart ...and nice bike, 1x1! So are you saying that your chain line of 75mm is paired to a 190/197mm rear hub? If so, then good to know as I plan on doing something almost identical. I'm hoping that the relatively longer chain stays of a cargo bike will make the pairing better tolerated.



1x1_Speed_Craig said:


> I utilized this Surly link, this Surly drivetrain chart, and this one from RaceFace a lot when planning the build for my Big Fat Dummy frameset.
> 
> I chose a SRAM GX 1x11 drivetrain for use with my 3.8" Surly Nate tires. With the intended 76mm chainline on the BFD, I ended up going with the RaceFace Turbine Cinch 170mm cranks and a flipped 30T chainring for a 75mm chainline, and 213mm Q-factor. It shifts beautifully, and the gear range is plenty adequate for me in Michigan. I'm used to riding single speeds and fixed gears, so I now have 10 speeds more than I'm used to.
> 
> ...


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## high_desert_mud (Jul 22, 2017)

I have shimano 1x11 on my Big Fat Dummy. For my use I definitely have the right setup.


gearing: 28t (eliptical) x 11-46t 
if you want gain ratios: 175mm cranks, 26x5" tires 
low end: This is geared the same as my 26x4" full-suspension fatbike. _PLENTY_ low for any pavement or gravel in existance. Subject to how loaded I am, I can also climb pretty steap single track 
high-end: this is about the only limitation. My top speed (pedaling) is about 20mph, and I'm spinning pretty fast then. 









I went shimano over sram because the complete drivetrain was $100's less expensive.

In the future, I may upgrade to an XD driver (rear hugs, freehub body) which would allow me to use sun-race 9x46t. In other words, keep the same low-end for climbing and gain some range for flat asphalt.


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## awai04 (Jul 29, 2004)

Thanks for the input, HDM! Yeah, I’ve decided to go 1x with a cargo bike. I initially thought 2x would be the “safe” choice. Though after some of the comments here and also reading Surly’s drivetrain comments on the BFD, 1x11 probably will work just fine.


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## 1x1_Speed_Craig (Jan 14, 2004)

awai04 said:


> Thanks for the Surly chart ...and nice bike, 1x1! So are you saying that your chain line of 75mm is paired to a 190/197mm rear hub? If so, then good to know as I plan on doing something almost identical. I'm hoping that the relatively longer chain stays of a cargo bike will make the pairing better tolerated.


That's absolutely right, awai04. The Surly chart helped me zero in on the crank options. It was a no-brainer with the 170mm Cinch crank/reversible chainring option getting within 1mm of the intended chainline (Surly says you should keep it within a few millimeters). I've always had great success with RaceFace parts, too.

Craig


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## 1x1_Speed_Craig (Jan 14, 2004)

There's also some good photos/information on this Facebook group.

https://www.facebook.com/groups/ILoveMySurlyBigDumy/


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## high_desert_mud (Jul 22, 2017)

1x1_Speed_Craig said:


> That's absolutely right, awai04. The Surly chart helped me zero in on the crank options. It was a no-brainer with the 170mm Cinch crank/reversible chainring option getting within 1mm of the intended chainline (Surly says you should keep it within a few millimeters). I've always had great success with RaceFace parts, too.
> 
> Craig


Surly did answer a number of my questions when building up my BFD. They were not perfect, but they were a hell of a lot better than, eg Chris king, who literally told me answering my questions on specific dimensions was 'doing My homework for me' (lol, due to this I went elsewhere for my parts...)

Note I believe Craig said he is running 4" tires. I agree the raceface affect 170 would be fine for 4" tires. I'm on 26 x 5 inch and the 190 spaced affect. I can hit all 1x11 gears with no rub, but literally with millimeters to spare . The 170mm would have interference for sure.


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