Tubing diameters

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gxaustin
Posts: 890
Joined: 23 Sep 2015, 12:07pm

Re: Tubing diameters

Post by gxaustin »

Valbrona wrote: 16 Oct 2021, 8:21am I don't think anyone who runs those courses market them as 'an opportunity to build your ideal frame'. You get a standard kit and a chance to learn basic framebuilding skills.
Oversized frame tubes will of course require a set of oversized lugs.
I had 853 frame tubes and forks with Columbus chain stays (oval) and seat stays (thin as possible 11mm). So much for a standard kit. I had a huge choice of lugs (but not too fancy). The geometry was based on my best bike, which had been fitted properly, and the resulting bike is excellent. The dimensions were applied to their test frame to check, in case refinements were needed. I asked for space for mudguards, without toe overlap. BBD will do you a bike fit if you need. I chose to have an A-head steerer but most would probably go for quill.
Phone them and ask.
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531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Tubing diameters

Post by 531colin »

Image631 fork blank Scan_20211018 by 531colin, on Flickr

Goodness knows where I got that, but the information is obviously available somewhere! "rake 15" is Reynolds code for 45mm offset.....thats obviously simpler than just printing "45mm offset"

The very first Spa frames were tourers built by Lee Cooper in 853. To fit low-rider bosses, Lee preferred to use Reynolds EB708 blades; they are one of the ones which come with an "R" sticker for the blade, rather than a tube-set sticker.
Lee recommended me to try 631 blades for comfort; I think I have seen them fitted with low-rider bosses, drilled through the middle of the tube, where the metal is less subjected to tension/compression either braking or bumping.

Re tube butting, the most obvious thing is don't use a long tube for a small frame, and cut off the butted end!
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