FS: rSogn module $730

[Ryan Nute]

Hi, all: I like the handling of the rSogn but it's a bit flexy for me.  Onwards!  Herewith the following:

Module: 1 rSogn frame (I got the early $500 price), medium (fits like a 56 road bike with high bars), fork (uncut steerer), Stronglight needle-bearing HS (black), VO Zeppelin fenders drilled to fit, Haulin' Colin plated rack.

Photo: http://www.flickr.com/photos/30684316@N08/6297365046/in/photostream

Price: $730. 

Shipping: Whatever it costs.

Thanks!

Ryan

[Michael_S]

Interesting input... everyone was clamoring for standard diameter tube sets and lightweight tubing during the on-line collaboration. Perhaps that is great for riders under 170lbs or so. I know Jan Heine has stated a big preference for bikes of this design. It seems for larger riders ( not sure of your  size Ryan) that maybe a 28.6 diameter  tube is a better choice.  Good luck on the sale anyway.

~mike

On Tuesday, February 28, 2012 5:29:18 PM UTC-8, rcnute wrote:

Hi, all: I like the handling of the rSogn but it's a bit flexy for me.  Onwards!  Herewith the following:

Module: 1 rSogn frame (I got the early $500 price), medium (fits like a 56 road bike with high bars), fork (uncut steerer), Stronglight needle-bearing HS (black), VO Zeppelin fenders drilled to fit, Haulin' Colin plated rack.

Photo: http://www.flickr.com/photos/30684316@N08) /6297365046/in/photostream

[Nick Payne]

Height and personal preference comes into it as well as weight. I have a couple of lugged steel frames with 1" top tube and 1-1/8" down tube, and a couple with 1-1/8" top tube and 1-1/4" down tube, and I prefer the latter, even for unloaded riding, though I only weigh about 145lbs. I am almost 6' tall, though, and ride frames around 61-62cm. For the same tubing wall thickness, a small frame will be less flexible than a large frame with the same tubing diameters, so a rider 6" shorter than me who weighed the same would probably prefer the smaller diameter tubing.

Nick

[Alex Wetmore]

That line is going to vary heavily depending on the rider.  I am about the same weight as Ryan and a little bit taller (which also makes the bike less stiff), but like bikes which are much more flexible than what he does.  I don't think that anyone can predict what is too flexible without experiencing it for themselves.  Personally I don't think that I've found it.

I'm sure that your builder is aware that most touring bikes made in the 70s and 80s, tens of thousands of which have been used to cross the US, had 1" top tubes.  It's his call to not put on a rear rack mounts, but you might find that it works just fine for you.

Of course the nice thing about low trail bikes is that you can carry most of the weight up front and thus have a frame that has a very flexible main triangle.

alex

---

From: rc...@googlegroups.com [rc...@googlegroups.com] on behalf of Michael_S [mikey...@rocketmail.com]
Sent: Tuesday, February 28, 2012 8:42 PM
To: rc...@googlegroups.com
Cc: intern...@googlegroups.com; 65...@googlegroups.com
Subject: Re: FS: rSogn module $730

Sean, I was referring to top tube diameter.  I have a custom 700C rando with standard (25.4) diameter top tube, and the builder said for someone my size ( 5'11 & 190 lbs) that he would not put rear rack mounts on the bike. It does have a front rando bag rack.

I guess what I'm getting at is that there is some weight point ( rider and gear) that stiffer tubing is needed in a given size.   It would be nice to know where that line is.

[Steve Palincsar]

On Wed, 2012-02-29 at 14:29 +0000, Alex Wetmore wrote:
> That line is going to vary heavily depending on the rider. I am about
> the same weight as Ryan and a little bit taller (which also makes the
> bike less stiff), but like bikes which are much more flexible than
> what he does. I don't think that anyone can predict what is too
> flexible without experiencing it for themselves. Personally I don't
> think that I've found it.
>
>
> I'm sure that your builder is aware that most touring bikes made in
> the 70s and 80s, tens of thousands of which have been used to cross
> the US, had 1" top tubes. It's his call to not put on a rear rack
> mounts, but you might find that it works just fine for you.
>
>
> Of course the nice thing about low trail bikes is that you can carry
> most of the weight up front and thus have a frame that has a very
> flexible main triangle.

Besides the tubing diameter, there's also a matter of tubing thickness.
Back in the 1970s, some of the best of those touring bikes used touring
grade 531:

The standard 531 set is the 531c racing tubeset which makes for
a
frame around 4 1/4lbs. This builds up into a fine responsive frame
ideally suited to road racing, but lacking a little stiffness in the bottom
bracket area. For smaller frame/riders it also make a nice touring
frame, but it really has too much flex to be good for someone carrying
full cyclecamping loads on a larger frame. To solve this weakness
531 st has a heavier gauge down tube which resists the flexing which
causes the dreaded speed wobbles on a loaded tourer. It also has
beefier stays for the loads imposed by cantilever brakes. The taper
gauge forks are of a flattened oval profile to give clearance for wider
tyres without using wide fork crowns, and that's it...

-- http://www.bretonbikes.com/reynolds.htm

I believe there's as much stiffness difference between 8/5/8 and 7/10/7
as there is between "standard" and "oversize" diameter for the same
tubing thickness.

[Alex Wetmore]

From: Steve Palincsar [pali...@his.com]

> I believe there's as much stiffness difference between 8/5/8 and 7/10/7
> as there is between "standard" and "oversize" diameter for the same
> tubing thickness.

I think you meant 10/7/10.

It is a good rule of thumb that for bicycle tubing that a wall thickness 0.2mm larger has similar stiffness to a tube which is 1/8" larger.

So 1" 9/6/9 and 1-1/8" 7/4/7 have similar stiffness.

The larger but thinner tube will be lighter (by about 60 grams if you compare 9/6/9 1" to 7/4/7 1-1/8").

The thinner tube will dent more easily unless it is using heat treated tubing. For normalized tubing (like 531 or 4130) 8/5/8 is as thin as one would want to go, and dents with about 60% of the force of 9/6/9 tubing.

1" 10/7/10 tubing is pretty uncommon these days, so I assumed that Michael's bike had 9/6/9 or lighter tubing. When I talked about my liking of flexible frames that was based on riding multiple bikes with standard diameter (1" top tube, 1-1/8" downtube) 7/4/7 and 8/5/8 tubes. The bikes that I've built myself and ride most often are 9/6/9 and 8/5/8 standard diameter tubes, and I'm building one now that has a mix of 8/5/8 and 7/4/7 oversized tubes. I used oversized tubes there to get the lugs and angles that I desired.

I had assumed that most people on this list knew these facts, so my original reply focused on saying that I don't think a universal rule can be built for determining what tubeset is too flexible based on rider weight. User preference is too important.

alex

[Steve Palincsar]

On Wed, 2012-02-29 at 15:46 +0000, Alex Wetmore wrote:
> From: Steve Palincsar [pali...@his.com]
> > I believe there's as much stiffness difference between 8/5/8 and 7/10/7
> > as there is between "standard" and "oversize" diameter for the same
> > tubing thickness.
>
> I think you meant 10/7/10.

Doh! Of course I did. Even thought that was what I was typing. Sorry.

>
> It is a good rule of thumb that for bicycle tubing that a wall thickness 0.2mm larger has similar stiffness to a tube which is 1/8" larger.
>
> So 1" 9/6/9 and 1-1/8" 7/4/7 have similar stiffness.
>
> The larger but thinner tube will be lighter (by about 60 grams if you compare 9/6/9 1" to 7/4/7 1-1/8").
>
> The thinner tube will dent more easily unless it is using heat treated tubing. For normalized tubing (like 531 or 4130) 8/5/8 is as thin as one would want to go, and dents with about 60% of the force of 9/6/9 tubing.
>
> 1" 10/7/10 tubing is pretty uncommon these days,

It may well be, but not so uncommon back in the 70s, especially not on
best quality purpose-built touring frames like the Jack Taylor Tourist
models.

Even today, Bruce Gordon uses 10/7/10 oversize on his Rock 'n Road Tour
models. And believe you me, that's mighty stiff.