Hello, I have an orange one of these. The tubing is Reynolds 725 and it is great.
I have just overcome the lack of disc brake mounts (see my recent thread on the subject!) but using a slighly modified Quad disc brake adapter that I found new on ebay (the seller has lots for approx £15 if you are interested).
It is ideal for the Singlespeed frame as it sits on the inside of the dropout. I gave it a reasonable test run today and it is solid - I am v happy so far.
Also, fitted my PCC 27.2mm dropper seatpost with remote; have had this 'in stock' for ages but the ability to switch between a full height for most efficient pedalling and a 4 inch drop is just great.
I have two other Dekerfs which I also love but the singlespeed is the one for life!
I am running mine with 80mm Fox RLTs which are enough for most circumstances.
Enjoy your build. Also, I have a couple of white and green Dekerf team tops and some bibs which are about to be put up for sale - if you are a 40-42ish chest then let me know.
Dekerf Phenomenon (for sale)
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