<![CDATA[GROUPJ - Blog]]>Mon, 14 Mar 2016 06:09:20 -0700Weebly<![CDATA[Carbon Fiber Frame Conversion]]>Tue, 19 Jan 2016 08:12:56 GMThttp://www.groupj.net/blog/carbon-fiber-frame-conversionA couple of months ago Steve called me and asked if JBobs could be used for carbon fiber frames.  He had been searching for couplings that he could use on his frame but wasn't having any luck with the well known sources until he found the GroupJ website. I told Steve I thought JBobs would work well but that we had not yet done a conversion. But, if he was willing to participate in an experiment, I would be willing to convert his frame in exchange for engineering data on how well the conversion worked.  Steve did not hesitate, and within a week or so I had a nice used Scattanti CFR frame delivered via UPS.
Steve's Scattanti CFR Frame with white bands indicating BFC placement - brake cable guide will need to move!
The frame has nominally round tubes with the top tube at 31.75mm and the down tube at 39.6mm.  There was significant taper in the down tube as it approached the bottom bracket, which dictated the BFC location.  
The stainless steel JBobs are joined to the carbon fiber tube (CFT) using high shear 100% solid epoxy and techniques developed in sail boat and motorsports applications. Before cutting Steve's frame in half, we ran some tests to insure that the metal-to-CFT bond was stronger that the parent tube.  Test were run on a 26mm diameter CFT bonded to to a -8 STD JBob, subjected to a cantilever bending moment.  The test demonstrated that the CFT collapsed under bearing load with the metal-to-CFT bond in tact. 
-08 Std JBob bonded to Carbon Fiber tube and mounted on test fixture
-08 JBob bonded to CFT under test - CFT failed before bonded joint failed
Steve's frame, while not new, was in nice shape so I wanted to demonstrate that JBobs could be installed without damaging the paint and clear coat.  A potential advantage to carbon fiber frame conversion is elimination of the need to repaint the frame.  A technique was developed to incrementally fit the couplings such that the prepped tube never extended beyond the coupling.
Steve's completed frame with -10 and -12 Std JBobs
Stay tuned as Steve tests his new travel frame and we learn how well the bonding technique holds up.
<![CDATA[Handmade Bikes and Beer]]>Mon, 18 Jan 2016 08:01:42 GMThttp://www.groupj.net/blog/handmade-bikes-and-beerI recently attended the Handmade Bike and Beer Festival in Portland Oregon, hosted by the Hopworks Urban Brewery  (HUB) on October 5-6, 2015.    What a great event; somewhere in the neighborhood of 30 local bicycle frame builders and suppliers and excellent craft brewed beer.  The frame builders had some very interesting custom bikes on offer from Titanium 29ers to grocery haulers to aluminum tandems.  The workmanship on the custom bikes is remarkable and it was so inspiring and educational to introduce JBobs to this group of elite craftsmen and craftswomen.  The majority of the builders are using Chrome moly tubing.  Lug brazing is still dominant among the CrMo builders but a lot of builders are using TIG.  There were also a good many aluminum and titanium builders.  If there were custom carbon builders there I missed them.
I went to the show with a handful of JBobs (Standard, Full Torque, P Option) and a stack of business cards.  My objective was to get some direct feedback on the JBob design from the builders and to understand what they wanted to see in a BFC.  Most builders were familiar with the current BFC offerings from other vendors, and many of them had used these couplings in their custom bikes.  All were very receptive and gave some great feedback:

  • The fit and finish of the JBobs were immediately appreciated – They really liked that JBobs came fully polished, saving them a lot of hand labor
  • They liked that JBobs were available in alternate materials of CrMo and Ti as well as the default 304SS
  • The Ritchey clamp was recognized as a tried-and-true coupling mechanism
  • The Full Torque BFC was by far of the most interest to the builders – they just felt more comfortable with the torque carrying capability.  While they recognized that the standard BFCs were probably adequate, they wanted top line equipment on their products.  (All of their bikes were to-die-for gorgeous)
  • The most common request from builders was for a “sleeker” coupling – particularly for the top tube.  Bulges or protrusions beyond the tube diameter were seen as negatives.  The down-tube coupling, which is surrounded by “protrusions” was seen to be not as much of a “sleek” issue.
  • Couplings for larger tube diameters were desired.  Builders now use 1.25 in. (31.75mm) and larger tubes, all the way up to 2.0 in. (50.8mm)
  • They would be most interested in engineering data on the strength of the coupled JBobs
This bike show had a lot to offer - Al checks out one of the bikes
Got Rain! - Get a Fender (or 2)
Dave Levy of Ti Cycles, and President of Oregon Bicycle Constructors Association checks out a Full Torque JBob
With his beautiful green, lugged, disk brake road bike in foreground, Mark Hall of Mahall Bikeworks provides valuable feedback on JBob marketing and would like to hear more about couplers for carbon fiber frames
Greg White at Magic Cycle Works spent a lot of time talking with Al and he would really like to see a "sleeker" top tube coupling
​At GroupJ Engineering we took all of this to heart and are at work on each of the above attributes of the “perfect” BFC.  Our first effort was to expand our line of BFCs to cover the tube diameter range from 1.0 to 1.5 in. (25.4 to 39.6 mm).  We do this with the two Ritchey clamps  (31.8 and 34.9 mm).   The larger diameter JBobs are also a bit “sleeker” as the clamp diameter is smaller than the tube OD. 
Two new JBob family members: Top: -12 Standard Bottom: -10 Standard
JBob Family: CW from upper left: -12, -9 w/P Option, -10, -8 Std w/P option/ w/ferrule, -8 Full Torque w/ferrule
​Keep your eye on this space for further BFC features and products.
<![CDATA[Introducing JBob]]>Mon, 14 Sep 2015 23:18:11 GMThttp://www.groupj.net/blog/introducing-jbobPicture
It is September 14 2015 and I am getting ready for the opening of GroupJ.net.  I have targeted the Hopworksbeer handmade bike and beer fest October 3-4, hosted by HUB microbrewery in Portland Oregon to launch my product.  Many of you know that Portland is a cycling meca.    Davis CA is the only place where I have seen more bicycles.  I spent the summer in Portland, visiting my daughter Jenni and her family, and have had the opportunity to ride all over the city and surrounding hills.    Portland loves their bikes and they seem to take care of them.  Of the bikes on the road, I would estimate that over 60% are vintage steel frame bakes.  The single speed minimalist bike is also very popular in Portland with a lot of newer tig welded chromoly frames.

So Portland is the ideal place to introduce GroupJ’s BFCs.  We will introduce our BFCs to the many custom frame builders at the Handmade Bikes and Beer Festival.  If you are in Portland please look for us.
Introducing JBob...........Jenni insisted that the BFC product needed a name.  We came up with several like Jloc, JCon, JCup; short catchy names and some of them described the product to a degree, but nothing quite stuck.   

Where did we get JBob?  Well that’s my dad, christened John Robert James he went by the name JBob.  JBob was a mechanical engineer, his specialty was aircraft bearing design, and he was on the design team for the liquid oxygen pump on the Atlas booster rocket engine that got Neil Armstong on the moon.  JBob was a motorcycle and car enthusiast and appreciated a good design.  JBob was always looking for the simple, elegant solution, so his is a fitting name for our first product.  

“GroupJ” grew from a need for a family email address, and referred to my James family.  I got that idea from Bob Tullius’ Group 44 Jaguar racing team which was a David throwing stones at, (and occasionally felling), the mighty Porsche 956s Goliaths in the IMSA series.

So JBob is the first.  My dream is that there are many more to come.

Group 44 Jaguar Racing Team
<![CDATA[SETTING UP THIS WEBSITE]]>Mon, 29 Jun 2015 22:53:18 GMThttp://www.groupj.net/blog/setting-up-this-website As I look forward to having more time to pursue MY interests, and consider what I want to do with MY time, I thought it would be fun to share these interests with others.  I am an engineer by trade and have always enjoyed designing a better mousetrap, or understanding the details behind a design.  I tend to have a wide range of interests and when I land on one I concentrate on it for some time, digging in and exploring, learning all I can about that subject, sometimes to the point that I am consumed with the subject.  I eventually discover something about the subject that I think is lacking or can be improved upon and then I take off and build, test, and develop that better mouse trap.  All are learning experiences, some are failures, but for many I think I made a contribution to the subject.  

This website is a chronicle of those contributions.  The subjects cover a broad spectrum and it would be rare to find someone that is an enthusiast for all of these subjects.  But there are enough nerds, gearheads, geeks, roadies, cyclists, stargazers, etc., that some will eventually find their way to this site and find something to further their passion.

I'll use this blog to touch on the various subjects in the website, giving the background as to how I became interested in them and what I hoped to contribute.

I wanted to start the site with the bicycle frame couplings (BFCs).  Ed, a cycling buddy of mine, bought a Ritchey Breakaway
TM bike and took it to Europe and around the world.  I was frustrated at not being able to find any off-the shelf couplings to convert my old Peugeot steel frame into a travel bike like Ed's.  I looked at the design of the Ritchey couplings. I thought they were a pretty straightforward design, discovered that you could purchase the Ritchey coupling clamps, and so dug in and built my own couplings.  I was so pleased with the finished bike (which I travel with extensively) that I decided to offer these couplings to other backyard bicycle builders.  These couplings fit within my philosophy of what is worth sharing: 1) They fill a gap (no one else was offering BFCs to the public), 2) They are an elegant design (esthetically pleasing, light weight, functional, and economical), and 3) I'm proud to put my name on them. I'd love to see these BFCs on bikes around the world. So I will launch this site when I get my BFC section complete and ready for public view.

I am not a web designer, but Matt, a friend of mine, is.  He guided me to Weebly to build my site and I am pretty thrilled with the results.  Some of the editing tools don't work the way my mechanical background would dictate but it seems to be a nice tool and pretty versatile.

So in summary this site contains contributions I am proud of.  If you find them useful please let me know. If you use them and see a way to improve them, please share.  If you have made similar contributions then I really want to hear from you.  Enjoy………..
                                                                                      Al James 150629