meech151 

The day I decided to start building frames I was at a cyclocross race and someone was riding a Bianchi aluminum frame w/carbon rear end. My thinking at that time was, "I can build a front triangle and stick on a carbon rear end and wallah, I have a bicycle frame." Anyway, things didn't go quite that easy and not necessarily in that direction but now I am back to wanting to build my first frame with a carbon rear end as I am curious to find out if this will produce a better racing frame over a complete steel frame. I am riding one of my first steel frames that I built using the geometry from my old Scott CR1 and the frame in size 58cm only weighs 3.5 lbs, i also put a steel fork on it and with the fork weighs only 5 lbs., not that bad. I could put a carbon fork on it and probably drop close to a pound. However, all steel frames are just a little more sluggish than these 1 kg carbon frames today, and while I know I can't produce a 2 lb. steel frame I just want to try and close the gap a bit. First, does the Columbus rear end save much or any weight over the average steel rear triangle and what are some of the pros and cons that you all know about. I have asked various people, some say it is much stiffer and lighter and some say its not that big of a difference. With that said, the only thing to do is to build it myself and see how it comes out. Next question, are the any hidden building aspects that I may be overlooking. It looks simple enough but so did building my first frame. Any insight would be appreciated. Thanks. Dimitri

unterhausen

I have no experience with these, but the general consensus is that there is no point in using them. I don't think it saves you much weight. Build one and get back to us on how it turns out. It was the fashion for a while to put carbon rear ends on Ti bikes. I was riding in a small group earlier this year, and I was the only one that didn't have a carbon rear end on a Ti bike. That was funny.

Allen

I'm going to put one on a bamboo build. I think I'm going to make it from scratch though, I want 135mm rear spacing, the carbon triangles I've seen don't come that wide.

KNEEL

I am with unterhausen on this one, there really is no point other than fasion to use them. however I just took my first ride on the one that I built as my 'A' bike for this years cyclocross season. I used it more as a 'skill builder' exercise than anything else and it was a fun build. I used the set up from nova which which was the zona front triangle with the Paul Taylor carbon wishbone with canti studs. I was, as you are, smitten with the apparent ease with which one could put it together, it wasnt bad but It didnt just fall together either, there were some procedural issues to work out and then there was the hidden cost of the recommended 3M adhesive and the special applicator . The cost of these is not so bad because I have a full carbon rear triangle to use on a frame that I bought 5 or 6 years ago when I had the same revelation that you are describing.

All in all I say if it interests you, then build it. You wont be sorry you did I guarantee you will learn something about frame building that you will use on another bike. If you have any specific questions about the build , ask away , i'm more than happy to share what little I know.

NoReg

How is the accuracy of these parts, and without going off topic much, how is the average accuracy of carbon forks. Whenever I measure up parts I don't always come away impressed. Maybe that means that the absolute accuracy isn't all that important, but I always try for accuracy in my own stuff.

KNEEL

The Tayor rear wishbone that I used seemed to be fine. plus its trim to fit. The end that the stays plug into has a straight section that you can trim a small amount from to fine tune the cantilever stud placement, It did seem a little wide at the bottom end but It sort of needed to be to be able to stuff it all together when you are gluing it up. I looks really good , but again, I'm not sure there is any benefit other than style, I like a hot set of fast backs just as well.

meech151 

Appreciate the help Kneel. I also understand what Peter Pan is talking about with the accuracy issues. As a new frame builder I would spend hours trying to get my frames perfectly aligned, then just for the heck of it I threw my Scott CR1 on my alignment table thinking it would be perfect and the seat tube was about 4 millimeters off, then the Carrera lugged, same situation. After this I stopped worrying about a millimeter. Hey, how much is the 3m adhesive for gluing the carbon? Do you think I could save some money and just use Elmer's? OK, I know that was a little stupid but I am coming off anesthesia from having a tooth cut out. I never thought one tooth could cause this much trouble.

Nessism

Some guys on the framebuilders forum recommend JB Weld to attach the rear triangle. No personal experience but something to consider.

As far as carbon rear triangles go in general, my opinion is that you are not going to save enough weight to matter so I wouldn't bother.