Uber weight weenie Seb K shows you all his insane 5.98kg Scott Spark. Machined-out powerlinks anyone?
Over to you Seb K…
My name is Sebastian Karimian and I have been building custom bikes for over 20 years. Over the years I have progressed to making parts for bikes from various materials from carbon to titanium. From chainrings and sprockets to carbon plugs and shims. I even made my own nuts and bolts from titanium.
I am already on the weight weenie scene and go by Seb K. I have already got the record for lightest mountain bike at four and a half kilos and it was featured on a few sites but that was years ago.
I then made the most titanium mountain bike ever made. That was a lot of work.
Now for this project I started with my Scott Spark Limited Edition frame. This bike had gone through so many changes over the years but I wanted to make it the lightest possible full suspension bike.
This was a two year project.
The frame has had all paint removed and sanded to 2000 grit and carbon polished. All black paint removed from aluminium sections. Shock links anodising removed and recessed areas made using the router and small sections drilled.
I have done a lot of machine work and also made some parts myself.
I made the yoke clamps, the titanium bolts and the seat pin (from a cut off from a Brompton rack gold anodised tubing).
The Gelu (with custom graphics) saddle, I drilled the holes and widened the centre and narrowed the edges a little (still keeping the overlap to protect the edges from damage).
About 96% of all the bolts have been hollowed in the drill press and all bolts replaced with titanium, aluminium and carbon peek.
Frame top boss and BB boss removed and plugged. Plugs made from thick carbon sheet and stems recessed for extra weight savings.
Main down tube bottle bosses removed and carbon peek inserts put in made by myself and finished with shortened and highly machined carbon peek bolts.
Carbon cranks with carbon axle. Splines drilled and carbon aluminium bonded insert also drilled. Crank bolt replaced with custom Extralite bolt highly machined in the lathe. Bolt flange removed and replaced with aluminium washer made by myself and recessed to save weight.
Custom chainring I made with special blue carbon fiber with aluminium strands in the weave finished with aluminium toothed ring pressed together and bonded then drilled holes under each tooth.
YBN 12 speed titanium chain shortened to length. Snap on link-pins carefully hollowed using specialised router bits.
Derailleur. Return and tension springs replaced with titanium springs I made. Body machined down and limit screws replaced with carbon peek. Guide wheel made by myself from carbon finished with full ceramic bearing and custom carbon insert. Tension wheel by Extralite narrowed in the lathe and one ceramic sealed bearing used with custom carbon insert. Carbon peek jockey wheel bolts used. Shortened jockey arm and inside jockey arm replaced with carbon arm I made with custom aluminium insert for the bolt. All bolts in derailleur hollowed. Custom blue derailleur extended arm machined down to save weight. Paul Components ball crimp with steel grub screw replaced with custom peek grub screw shortened in the lathe. Gear shifter body removed and machined and screws replaced with titanium rainbow screws. Custom cassette from KCNC mixed with Ceradure cassette highly drilled with custom carbon centre. Custom housing lightest in the world finished with KCNC titanium gear cable.
Fork is RockShox SID World Cup Carbon. Seals replaced with custom after market enduro silicon seals. Some machining on the legs needed for it to fit. Fork brace hollowed and machined down as well as bas of legs. Fork damper replaced with tf tuned air damper and all knobs and dials replaced with hopp carbon parts. Hopp carbon air valve caps on both shock and fork machined down in the lathe to save weight. Axle by Carbon Ti machined centre in the lathe and hex hole completely machined away. Other side of axle near threaded area hex stamped in. Rear shock full carbon DT Swiss with some custom machining done.
Tune Kill Hill calipers with Extralite bolts fully hollowed. Custom after market hoses with 3 way connector for one lever controlling two brakes. Barb connectors replaced with custom anodised aerospace grade aluminium ones. 3 way connector made from aerospace grade aluminium. Lever blue anodising removed and sections machined to save weight. Levers highly machined. Barrel nut made by myself from titanium. Scrub rotors with Extralite hollowed titanium bolts.
Aerolite pedals with custom high strength aluminium axles with custom coating. Pedal bodies replaced with custom carbon ones slightly shortened. Axles slightly shortened. End caps heavily recessed.
Stem custom machined very highly with the router. Finished with hollow custom machined titanium bolts.
Very custom computer mount made by myself with custom semi circle aluminium nuts and titanium bolts with custom carbon body.
Prototype carbon rims finished with custom carbon spokes and Tune Prince and Tune Princess hubs with carbon flanges and custom carbon composite end caps. Rox rim tape cut and holes stamped for valves. Rear skewer made from custom titanium hollow rod threaded by myself and end caps from Tune highly machined and recessed with custom spline made by myself.
Ride Now TPU tube with valve stems cut off and custom aluminium inserts put in finished with custom carbon composite valve nuts. Maxxi Lite tyres.
Custom blue foam grips shortened and tapered in the lathe.
Custom bar plugs by Extralite sanded and painted copper with 2 coats of clear.
Custom Schmolke bar made from T1000 fibres with custom black graphics.
Custom carbon head badge I made.
All bearings are ceramic.
This is by far the lightest full suspension mountain bike (fully adjustable shocks, disc brakes, 10-speed drivetrain) in the world and I believe ever. 5.98kg.
Oh and I also made the carbon stand the bike is on. 2 weeks to design and build the stand. Possibly the lightest bike stand in the world too .
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Maybe not weight weenie enough, but Hope make them. Excellent article a few years back in the magazine about it, was a project by someone there who only had use of one hand. If MrsMC had continued riding, I was going to get a set.
I had a single brake lever set up for polo for about three weeks.
Its not that bad aslong as the bback brake engages first.
Its **** awful if the front brake engages first though.
I always remember when I built my stupidly light Cotic Soda, took it out for the first ride, went to ride over a rock and it just bounced off instead. Having to learn how to ride a bike with less momentum is bizarre.