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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I don’t want to piss on anyone’s chips – technically it’s a heck of an achievement. I’d be very keen to see a ride review over some decent trails though!
Hmmm. I really don’t think so
I think the problem is these builds go too far (drilling all the bolts, 1 brake lever, removing structural bits of forks/dampers) or not far enough. (Gears, 29” wheels, >120mm cranks, fitting a computer) so the metric by which they’re judged is always changing. If someone set up a competition where there were actual rules to follow, followed by a ride test by a fully grown adult (control size), I might give more of a shit about these art (and they are art. As they have no purpose other than themselves) pieces. Really really expensive BSOs
Yes, I would like to see them tested over a rough cross country trail. A dropper post, grippy tyres, decent brakes, a wide range cassette, and proper pedals add a bit of weight, but they make the bike faster and easier to ride on proper trails.
Hmmm. I really don’t think so
Work of art to be hung on a wall, yes very pretty. I might trust it on a gentle ride to the shops but with one brake lever for two brakes I’d have to hike it down some steep descents which require a handful of front brake and an occasional gentle squeeze on the rear. Replacement aluminium bolts for anything more critical than a bottle cage no thank you – the bolt size was chosen assuming the strength of steel. The first requirement of a mountain bike is that it can be safely ridden down a mountain bike trail, on that measure it fails.
Came back to say – the owner better be a skinny ass whippet, rather than a juggernaut like me…
Reminds me of the nonsense I used to lust over in the early 90s, but even they were bikes you could ride.
Like others have said I think I’d take issue with the claim it’s a full suspension mountain bike because you couldn’t ride it down the road, let alone a mountain. You’d probably find it easier on a similar weight UCI approved TdF bike.
That chain tension upsets me more than the loose cables.
Wonder if there’s an audio track of it being ridden anywhere?
F***ing Sh**e. Totally pointless waste of time and effort. Why not drill some massive holes in the frame and tyres seeing as it’s completely unrideable anyway.
I disagree. As a fairly competent 24hr racer I would love a Garmin which lasted the duration but was small and, above all, simple, just to record. I use two Garmin 200s, each with 16hrs of battery. I have a very comprehensive light set up but no dynamo, too draggy/faffy.
In what world is that pretty? It’s a dog’s dinner of mismatched colours, the cabling males it look like a broken clothes dryer, and the stupid single brake lever makes it near unusable as a mountain bike.
Just a stupid waste of time, energy and materials
I assume that is something to do with….
Agree with all the comments. Unrideable waste of time.
Patio needs weeding 😆
No. He’s removed so much weight from the pedals (and the paint obvs) that you just can’t see them.
The Dangerholm Scott Spark is absolutely gorgeous compared to this world’s most expensive BSO
I was reading the Bikeradar piece on Dangerholm’s 9.5kg Scott Spark (coincidentally) over the weekend. Obviously it’s quite a different build, but definitely more a bike I’d actually ride.
https://www.bikeradar.com/features/pro-bike/dangerholm-scott-spark-rc-2
Its not that sexy.
I have a photo of my fs bike which will make it the lightest bike in the world (obviously cannot be ridden etc but lightest in the world ;-p I would class daganholm’s bike as the realistic lightest bike as it can be ridden offroad as intended and it also looks a lot nicer than the op bike.
Am 8 imagining it or are those tyres flat to save weight?
285g tyres. If they’re not flat now they will be.in a minute. (in the unlikely event this thing is ever used)
Totally agree. Far enough to be useless, but not as far as a useless bike could go
Hats off to the effort put in and I am definitely new to this level of weightweenieism. He says in the comments of the youtube video that it’s rideable on xc with a rider weight limit of 70kg. Would be good to see it in action.
I think its quite funny that everyone comments on the pedals.
Out of everything they’re thr least extreme thing, bit scary on a mountainbike but they look perfectly functional, afterall how different to speedplays etc are they really, just moving the pedal body to the shoe.
I am fully on board with the concept of it being a weird waste of time though.
There should be a Concours des Machines type of event for these things. Ride a few different events or stages without any spares and see if they make it or how long they last. Bit like MTB race weekends for some in 1992..