designing a porteur

[Scott Loveless]

Hello!

After several years of trial and error, riding bikes that are both high and low trail (rSogn), carrying loads in various configurations, including a basket over the front wheel, I've come to the conclusion that I need a porteur.  I have a few questions about what would work best, but I'll lay out my requirements first.

-Money's an issue.  When isn't it?  A custom frame is likely out of the question, but I can probably swing a custom rack.  I like the looks of the prototypes shown with various Kogswell P/R bikes.
-650x42b tires with fenders.
-Vertical dropouts.  Horizontal dropouts are a deal-killer.
-Derailleur gears.  I live in a moderately hilly area, and getting out of town for any distance will often involve long, steep climbs.
-The ability to carry up to 30 pounds on the front rack.  An example: twice a month I purchase a meat bundle from the local grocer.  It weighs anywhere from 20 to 25 pounds.  They hand it to me in a box, which I carry to the register, pay, then spend some time beside my bike redistributing the contents into two panniers.  Then I have to break down the box and toss it in their dumpster.  I'd like to simply strap it to the front rack and be on my way.  This is likely the extreme of what I would carry on a semi-regular basis, but I'd still like to be able to.
-Upright-ish riding position.  Porteur bar, Albatross, something like that.  An injury in January, followed by surgery in April has left me much less flexible than before.  Drop bars are out for the foreseeable future.

Right now, I have a basket and front rack on my 520.  Even a light load affects the handling in a negative way, requiring constant steering correction.  I do, however, really like the convenience of that basket.  My thoughts were to pick up something like a Soma Grand Randonneur or a VO Polyvalent.  Now that VO isn't available, at least for a while, I'm leaning toward the Soma.  Other than the frame and having a rack made, I'll only need rims.  I have every other part I could possibly need.  I thought I had this figured out.  Then I started questioning my logic.

The BQ review of the Kogswell P/R suggested the lower trail fork would handle a heavy front load better, but I wonder if more fork offset and a little less head angle might do a better job of putting the load behind the front axle.  I ordered and read Volume 5 of BQ and I'm still scratching my head.  I feel like I've missed something obvious.  Attached is a screenshot of Jim G's trail calculator comparing the Soma GR on the left with my 520 on the right.  Trail and flop measurements aren't that different.  You'll notice I've put in 80mm for the fork offset.  That's an Electra Ticino fork, which I have and intend to put on the 520 for a little road testing.

Anyway, to sum things up, I'm looking for opinions on carrying a heavy load above the front wheel and configuring a bike to do so.  Thanks so much, and have a happy Holiday.

​

--
Scott Loveless
Camp Hill, PA  USA
http://www.twosixteen.com/fivetoedsloth/
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[Jeffrey Kane]

Scott -- this is an odd one -- and I have no experience with it -- but if your 520 will accept a 1 1/8" steerer tube the Crust Clydesdale fork is at least worth a look.

https://www.crustbikes.com/products/clydesdale-fork?variant=21402293697

jsk

[Paul Sherman]

IIRC the BQ load carrying tests found that slightly higher trail worked better with heavier loads on the front of the bike. A trail closer to 40mm would probably work a bit better than 30mm. It might be cheaper to have a builder build/modify a fork than to buy a new frame with non-ideal geometry.

Personally, I would go with Jeffrey's suggestion. It ticks all of the boxes except for the 650b wheels. If you only need all that capacity once or twice a month, you could feasibly have separate cockpits and just swap forks as needed (again, assuming your 520 has a 1 1/8 steerer).

Paul
Pasadena, CA

(Disclosure: I happen to think that crust fork is really, really cool and want one myself)

[John Speare]

I agree with the direction Jeffrey is going here -- I don't have experience with the Crust fork, but if putting a 30lb box on the front rack is a core scenario that needs to handle well, then I think you'll not be thrilled with the solutions you've outlined above.

IME -- porteurs with ~40mm of trail are great for loads up to around 15 lbs -- above that, it's more of a chore to keep the front behaving in a predictable way. Nearly all of my porteurs/front rack bikes have been 73 headtube angle, so perhaps your ideas with messing with longer rake may work -- I really don't understand the nuance of the interplay there.  For the kinds of loads you're talking about, I think a cylce truck might be more useful. Soma has one -- based in some part on Alex's SH-80. That bike handles wonderfully with heavy (30+ lbs) loads. And there are really compelling small-wheeled (20" wheels) popping up here and there in my various feeds that look super sensible.

[Jeremy Tavan]

Scott,

I've recently completed a high-end build of a Kogswell P/R (with the highest-offset, lowest-trail fork) as a porteur bike and can speak a little bit. It took quite a bit of tweaking to get the loaded handling working right, but we did finally figure it out and I'm now very pleased with how things work. Handling is light and responsive, and I've (knock on wood) not encountered any shimmy or speed wobble. I've carried 25-30lb of groceries, which is about all my current front bag will hold. I guess if I bought nothing but beer I could get a heavier load into the available space. 

Key areas of attention:

• Getting weight behind the front axle. This was critical, and the single most important thing we did. We were limited in that we modified an existing rack (Soma stainless porteur) rather than fabricating one from scratch. With the rack mounted perfectly level there was too much weight forward of the axle, and heavy loads led to outright terrifying handling. Tilting the rack back an inch or so made an enormous difference. Now the load is much more behind the axle, and the steering is light and responsive even under load. You can't eliminate the mass's momentum, but the balanced feeling is very confidence-inspiring. With a custom front rack you could probably just make sure to move the platform back as far as your brake cable or head tube will allow. Aim for 4 points of attachment for the rack, rather than 2 dropouts plus a center bolt. You want side to side stiffness for load carrying. I have custom struts attaching the rack to the fork crown bosses.

• Tire pressure. I've found that (at least with supple tires, and I haven't tried anything non-supple on this bike), the front tire pressure is important to handling under load. When I carry heavy loads I also pump the front tire up a bit higher than I would for general riding comfort. 

• Rider weight distribution. I'm using a MAP/Ahearne handlebar which comes back a little bit but not dramatically like a porteur or albatross bar. My riding position is fairly aggressive and forward for a loaded cargo bike, because that puts a little more rider weight on the front, which helps stabilize handling. Tweaks like moving to a longer stem make a noticeable difference. 

Anyway, just a few points to think about. I really like the P/R porteur as currently set up because when unloaded it can be a nice fast ride, and the handling doesn't change all that much under load. But it's not a true heavy hauler - for that I'd be looking more at xtracycles and trailers. That said, I also like the idea of a small-front-wheel cargo bike approach, and might be tempted to try one of those on a spare frame just for the WTF factor. Fun!

/Jeremy

[Scott Loveless]

Yes, the 520 has a 1-1/8" steerer.  That said, and thanks for the suggestions, but I'm really not interested in the cycle truck way of doing this.  If the bike were only used for short distances with heavy loads, that might be ideal.  But the 30 pound requirement is simply to be able to handle the extreme heavy end of what I might carry, and that wouldn't be every day.  In my mind, I see a more traditional Parisian porteur.

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[Scott Loveless]

Jeremy,

This is what I was looking for.  Thanks!  Do you happen to have photos of your rack modifications?

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[Jeremy Tavan]

Sure - http://cl.ly/2c2Q1O0l0n1q/27414300533_cf98713862_k.jpg shows an early iteration of the bike project. The tires, stem, pedals have all changed since then. This also shows the rack before we re-brazed the stays at a shallower angle, tilting back the rack. The rack backstop is now JUST in front of the brake cable. This image should give you an idea of what I mean by struts, though. Note that the light mount is also custom. 

/Jeremy

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[Michael Rivers]

I really like the Hauling Colin rack on my rSogn porteur. This is my haul 30lbs of camera equipment on the front, and still have room for groceries in the back panniers bicycle. Fat tires are particularly welcome when the bike is loaded. These are Schwalbe 50mm that Riv used to sell. VO 60mm steel fenders are sturdy, and the rSogn was designed for fenders so even I could obtain a nice fender line.

I like the Wald basket on the front, but if I remember correctly, there were some bags designed specifically for this rack.

https://flic.kr/p/Po7tHB

Michael

[Michael Rivers]

Sorry, I forgot to mention that I also have a Soma GR v1, that is a very different bike. I set it up differently, but don't think the tires are big enough, or the frame sturdy enough for bigger loads. I weigh 200 lbs to start.

https://flic.kr/p/C3MFte

Michael

[satanas]

Count me in as another who is tempted to order one of the Crust forks. And I'd be extremely reluctant to carry a heavy load above the wheel on a GR as IMHO the top tube and head tube just aren't stiff enough; I'd expect the handling to be truly wretched, especially doing tight turns at low speed. (Things are bad enough with front panniers on a Tubus Tara.) Nor am I a fan of forks with huge offsets as I'm inclined to think these increase the likelihood of shimmy.

Maybe vegetarianism is a better option, or else collecting roadkill on a daily basis. Owl jerky used to be popular with VVA...

Later,
Stephen

[James Black]

Scott,

I think your best bet, especially if money is a factor and for someone not afraid to wrench on bikes, is to source a good vintage bike with the right attributes. Porteurs handle better, in my opinion, with a steeper head angle (73 is better than 72), although they are more likely to shimmy when ridden no-hands.

My Nishiki Ultra Tour was fantastic:

https://www.flickr.com/photos/10533076@N08/sets/72157627312040158/

Until the frame broke at the dropout, at least, but that wouldn't stop me from getting another one. I have since then moved the excellent front rack to my Centurion Pro Tour.

The Nishiki Royal would be a good candidate, as it has good clearances for 650x42, vertical dropouts, and the right 73/63mm front end, but it might be hard to find one. The 1979-1983 Nishiki International would be great as well if you can live with horizontal dropouts, or the Fuji America.

James Black

Los Angeles, CA

On Wednesday, November 23, 2016 at 10:14:54 AM UTC-8, Scott Loveless wrote:

[Alistair Spence]

On Wed, Nov 23, 2016 at 10:14 AM, Scott Loveless <sdlov...@gmail.com> wrote:

Anyway, to sum things up, I'm looking for opinions on carrying a heavy load above the front wheel and configuring a bike to do so.  Thanks so much, and have a happy Holiday.

It's hard to go wrong with 73 deg. HTA and 38mm of trail on something like Hetre tires. I've rigged up several porteur type bikes over the years with trail ranging from 27mm to 65mm and while they were all rideable I found that trail numbers in the high thirties work well for porteur type loads ie. 10 to 40lbs.

I'm not convinced that putting the centre of gravity of the load behind the front axle is what is crucial. I think it's more that the load needs to be as close to the steering axis (ie. as close to the headtube) as possible. A corollary of this often is that the load will end up behind the front axle. This minimizes the moment of inertia of the rotating load/fork/wheel system which is related to the distance of the C of G from the steering axis, squared.

Your 520, with that slacker HTA is going to have more flop, but as the trail calculator shows it's not a deal breaker, in my experience anyway. I have a Nashabar tandem with a flop number in the low 20's that I built a front cargo rack for. When loaded up it does take more effort to "dig it out" of corners but I'm running that bike with Albatross bars so the extra leverage helps there.

Alistair Spence,

Seattle, WA.

[mitch....@gmail.com]

On Thursday, November 24, 2016 at 6:19:41 AM UTC-7, Michael Rivers wrote:

I really like the Hauling Colin rack on my rSogn porteur.

Anyone know the dimensions of the standard Haulin Colin porteur rack, length, width, weight, tubing size?

thanks,

Mitch 

[Paul Sherman]

http://www.cyclefab.net/buy-stuff/haulin-colin-porteur-rack

Everything but weight is listed here.

Paul

[Frankwurst]

I bought mine when they had the rSogn/Swift bag combo.Great racks and bags as well. I waffled on it because I'm generally to frugal to spend that much on something I might not like but I really like both.

[Scott Loveless]

Thanks, James.  What happened to the geometry of the Nishiki International in 1979?  I have a 1977 International, which had a VO porteur rack on it years ago.  My recollection was the the rack was too flexy, and that made it hard to judge if the geometry of the bike was appropriate.  I did a 650b conversion on that bike, but was never really satisfied with it.  559 calipers were too short.  750 center pulls were too squishy.

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[Scott Loveless]

Michael,

Thanks for the photos. I had an rSogn, but stupidly sold it a few
years ago. (Of all the bikes that I have passed through my grubby
little mitts, this is the one I regret parting with.) I never thought
of it as "stout", and would have assumed the GR to be stiffer.

[James Black]

Hi Scott:

The earlier Nishiki Internationals are nice, but at some point in the late 70s (maybe earlier than 1979) the build quality and detailing got a little more refined, in my opinion. The geometry was fairly consistent, I think. They also changed from using centerpulls to sidepulls, which would put the brake reach at a better spot for a 650b conversion.

The other thing I like about these Nishikis is that they have a relatively long top tube relative to seat tube.

Cheers,

James

[Bill M.]

The rSogn frame is reasonably lively, but the fork is pretty stout . Just the ticket for a porteur IMO.

Bill

Stockton, CA

[Ryan Conrad]

James:

that Nishiki really does look great, but that rack is incredible. What's the story with it?

Ryan