001 – Lugged Road Frame

The build

It all began 5 or 6 years ago when I built a frame for my university dissertation, my skills and experience were lacking and the finish was far from perfect but it got me started. This frame is the first frame I have produced for Sideways and I wanted to revisit my dissertation design to apply my new knowledge and skills.

The main brief revolves around the lugged style as I think some of the carbon frames of the 90s and early 00s had an awesome look to them. Of course, lugged carbon is never going to be the most high performance or low weight so don’t expect anything too svelte!

I began this frame in a new workshop so I had my work cut out to set up all my tooling and machinery for his build. The first step was to create a machine for roll wrapping and cellophaning the tubes, I chose this method as I had recently spent some time working in a fishing rod/tubing company and wanted to explore the process more. I made 3 mandrels: 27.2mm, 39mm and 10mm. Because of how the roll wrapping process works the mandrels will determine the internal dimensions of the tubes which is incredibly useful for producing seat tubes as it means a good seatpost fit can be designed from the start.

10mm Inner diameter tube wrapped in tape and ready for curing. I had some leftover pre-preg so this is on a steel mandrel and will get cured at 120°C

With the tubes sorted it was time for the complex parts, the lugs. The process for these is to use a clam shell mould with a flexible internal bladder that will be inflated to provide consolidation. This process is simple enough to conceive but has been challenging to put into action as there have been lots of problems along the way. The final solution was to use silicone bladders and 3D Printed moulds. The bladders were a great success but the moulds would, unsurprisingly, last only one or two pulls but this is okay for a quick one off build.

Laying up the lugs was tricky as they are highly contoured parts with a lot of material and multiple mould parts. To make things easier I chose to make some DIY pre-preg by wetting out the fabric between two sheets of plastic then squeegeeing any excess out, this can then be left until the resin has just started to gel and it has much better tack qualities, you just run the risk of having a far shorter lay up window! One thing I didn’t get to try was filling the silicone bladders with wax to make them solid so I could do some of the lay up around them. Next time.

With the lugs complete I had to make a few ancillaries. Dropouts, brake bridge and cable bosses. I made these in a compression mould sometimes with more than 20 layers of carbon in! With those complete I made a rudimentary jig and got everything ready to bond the frame. An issue that appeared at this point was that using inflatable bladders means the inner dimensions of the lugs were never guaranteed and the roll wrapping meant the outer dimensions of the tubes were also not guaranteed, this lead to lots of back and forth sanding and fitting as my calculated wall thicknesses were close but I didn’t design quite enough tolerance.

At this point I am extremely happy with the frame and confident in the structure and strength of all parts I have made and assembled. The final piece of the puzzle was to paint the frame. A process that I usually avoid as I don’t have to knowledge or equipment to do it properly. However, I persevered and gave the frame some paint. It’s far from perfect but for a couple of cans of Spray.Bike paint and a Wilko tomato greenhouse I think it has come out alright. Still lots to improve on for next time though.

The Ride

I planned the weight to be 1000 grams without the BB Shell. So with a 100 gram Steel BB shell from Bear Frame Supplies and some paint the frame comes out exactly as planned. Definitely not lightweight. Oh well, this frame was a little more about style than performance.

As for how the frame rides, it is one of the first frames in a long time that actually fits me! I designed it around the fit that I have found comfortable for me over the years and it is wonderful to ride a frame that doesn’t have an abnormally short stem or no seatpost showing.

I assembled my SRAM Red 10 speed groupset (which is mostly Force), Easton wheels and Deda Finishing kit onto the frame to really make it feel like 2010! Jokes aside, it’s the best kit I have and personally I really enjoy the shifting action of SRAM shifters, although I have never tried high end Shimano to compare. The frame feels great to ride and has great confidence into corners, it feels stiff when you put the power down and genuinely seems to have some of that mystical “vertical compliance” that reviewers always speak of.

In conclusion, lugged frames are not something I would be overly eager to build again as they require a lot of tooling and a lot of fettling however I think with a few more frames under my belt and a bit more experience in my own workshop I will make another lugged frame…

Wrong seatpost and saddle in this photo. But it is undeniably scenic

Leave a Comment

Your email address will not be published. Required fields are marked *