HOW TO BUILD A CARBON BICYCLE SEAT AND RAILS

Another seat project at snails pace due to other commitments. Design based on SMP carbon seat by Sella. I have added more curve for the pelvic area on the mold plug. Will only know when I ride on it for a few hours. This way I can always add more material to reduce the curve but the dimensions are similar. Watch this space

FLEXI-CARBON SEAT

My brother in law is in need of a new seat for a big ride we are doing in Africa in May. I wanted to build him a carbon seat so I designed a prototype that I have not seen on the market yet. Not only is it light but its super flexible for carbon. I have introduced a ‘suspension’ tongue to control movement. This design enables me to modify the flex after it is built for the rider.

CARBON CAR CRASH

Another victim to remind us that car doors opening into the road can be a real hazard to any cyclist. This 2012 Wilier XP suffered a frame fracture and shifter damage. A fairly simple repair in 4 x 300 Uni layup. Nice and thin but strong. You can see the tape covering the decal to ensure no accidents happen. I safely got away with it this time. I varnished and did not cover the repair as the rest of the frame is clear coat + Carbon repairs are cool!

CARBON SEAT POSTS AND SEAT RAILS

A common problem with carbon is over-tightening. Here I am rebuilding a deep crack. Its important to ensure all layers are exposed to build a strong repair.

This Fi’z’ik seat got the MTB treatment and cracked in 3 stress areas. Again you can see how brutal I get in clearing damaged areas for structural repairs that could cause direct injury. I don’t always take these on for legal reasons.

They are now successfully back in the field were they belong and so far no returns!

ALLOY WELDING

Scott Genius MC20 Carbon frame with alloy rear stay mounting: Broken rear stay mount. Normally this is a throw away frame because the cracked alloy part is too close to the carbon frame. Epoxy and heat don’t mix. I welded the alloy mount at the same time protecting the carbon frame. In fact I increased the area of support as this is a known problem on this model.

SEAT STAY

Got this Cube Litening that had a side impact. The seat stay was broken off at the top and bottom of the chain stay. The seat stay piece was also snapped into two pieces. The first job was to align the broken parts together with a strong epoxy on the frame itself. Once cured in perfect alignment the repair could begin. Each break was rebuilt with 5 layups of different CF weave to ensure stiffness. In this case I resprayed the repair.

BRAKING SURFACE

Another sad but all too typical worn brake tracks on perfectly good wheels. It’s a time consuming job to ensure the re-build is flush, level and can withstand high heat and abrasion. Don’t ask what I use…it’s not off-the-shelf epoxy.

WHEELS

I was sent a set of Bontrager 700’s that had melted down an Alpine run. The rear wheel profile was deformed from the incorrect pads and brake surface was de-laminated. Luckily the wheel was still true so I took on the project.

Firstly the profile had to be reset by creating a mold of the correct profile. After cutting away the damaged area I rebuilt the wheel and brake surface. It is important to get the weight the same so there is no bias to a heaver side. The wheels are as good as new.

FRAMES

Bianchi Infinito. Down tube was damaged. 8 x uni and bi carbon fibre layup. Frame still weighs as per original

The Bianchi Infinito

The Bianchi Infinito back to its former glory. Complete bike weighs 6.7kg