A new lightweight contender (and it fits in a suitcase!)

Discuss light weight issues concerning road bikes & parts.
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Posts: 115
Joined: Tue Sep 07, 2004 1:27 pm
Location: London, UK

by jahknob

Hi everyone. I'm new to the board (though I've been studying it avidly for some time).

I have a new bike, several years in the making, currently on display at the Cycle Show in London (on the Cycling Plus magazine stand). The Roberts ULT Compact is the lightest bike at the show - and is probably the lightest "folding" bike in the world (it uses S&S BTCs, so will fit into a large suitcase/backpack).

I'm sorry that the picture doesn't really do it justice - I'll have better ones after the show (it was only finished the night before). The bike is still without self-extracting crank bolts and cable splitters, but I've added in the weights in the list of parts below (all verified on a digital scale +/-1g).
The tubs in the pic are Conti Comp GP 19mm - I rode the bike to the show just after taking the pics, so it's only done a couple of miles - no durability questions yet please!

The bike will get a proper testing when I fly out to France in October. I've quoted both tyre weights, as that's the one essential change necessary for riding on the road (I think).

I've also got a few upgrades in mind for 2005, funds permitting. Would welcome any additional suggestions, comments or questions.


Frame (front) Roberts Columbus Foco, S&S BTCs 575
Frame (rear) Ditto + Dedacciai Blacktail 1013
Fork THM Scapula SP Tuned 1.125" (182mm) 222
Headset Extralite The Head 1.125" 62
Spacer 5mm carbon 1.125" 2
Ahead cap/Plug AX Lightness (5g) + Extralite UltraStar (9g) 14
Seatpost collar Spicer Cycles Ti 16
Stem Extralite Roadstem UL 1.125" 110mm 97
Handlebar Schmolke Carbon TLO (42cm ctr-ctr) 142
Seatpost AX Lightness 350mm 144
Saddle AX Lightness Sprint Superlight 54
Crankarms Cat Carbon (L arm 114g / R arm 179g) 295
BB TNT SL Ti 107mm 116
Chainrings Carbon 38/48 (37/26g) 63
C’ring bolts/Washers Miscellaneous aluminium 11
Crank bolts Middleburn self-extracting Ti (tuned) 20
Brake/Shift levers (2) 2004 Campy Ergo 10 Carbon (BTP clamps) 310
Brakes (2) Zero Gravity (w/Deda bolt) 135g
Pads/Bolts Zipp carbon 46
Brake cables CLB Alloy 55
Rear derailleur Precision Billet Proshift (custom short cage) 163
Front derailleur 2004 Campagnolo Record 10 Carbon 65
Derailleur cables Gore Ultralight 54
Cable splitters (3) Reset Racing 30
Pedals (2) Speedplay X/1 Ti (BTP alloy plates) 130
Chain Wippermann Connex 9X1 Ti (102 links) 232
Cassette lockring EFFE aluminium 5
Cassette EFFE aluminium one-piece 11-21 89
Front hub Tune Mig 66 (front wheel 461g) 85
Rear hub Tune Mag 160 (rear wheel 543g) 176
Rims (2) LEW Custom (14/16 spokes) 560
Spokes (30) DT Revolution/DB 173
Nipples (30) DT Al 10
Tubs (2) Tufo Elite 220
QR (2) Heylight Al/Ti 48
Bar tape Storck (black) + plugs 59
Tub tape Jantex 22
Bottle cages (2) BTP Kevlar 12
Total (Show Build) 5525 (12lbs2oz)
To make "useable" need to change to a pair of Conti/Veloflex/Tufo road tubs (circa 225g ea) 5735 (12lb10oz)
Last edited by jahknob on Wed Nov 03, 2004 2:27 am, edited 2 times in total.

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by nikh

Sweet ride.

Is this a Chas Roberts frame?

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by gandini

That's one fancy bike! Small bikes always come out looking good both on the road and on the scale. You've put together some seriously light parts. That rear derailleur looks beefy, but weighs little. What are those 110g Tufos like to ride? Woohoo. I commute on the S3 Lite 215s and they are very nice even with sealant in them (the desert in SW USA has nasty thorns called goatheads, which can penetrate kevlar vests...!)

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by marktickner

I saw your bike at the show and I was very impressed. There were certainly many people on your stand ogling and prodding and picking the bike up etc... After finally managing to see it up close I was certainly impressed by the overall finish. A credit to you.
As a every day bike for riding, I am not sure of the durability but only training time will tell.
Nice bike!

ps: Was the Stork Stilletto next to the Roberts yours also? Now that bike was sweeeet although probably not as light but maybe better for durability?

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by jahknob

The bike is effectively a 55cm, though slightly longer in the top tube. I make no bones about the fact that some of the parts (wheels, seatpost, saddle, stem, bars, crank, forks) have a weight limit (75-85kg) and I am no gear masher (68-70kg), so could build the bike accordingly.

The frame was built and the bike assembled by Chas Roberts and his crew in South London - it's the first steel frame they've ever done with TIG welding. Certainly, if you want lugged or fillet-brazed steel, I know of no finer framebuilder. The TiG-ing isn't pretty, but it does save weight. Every gram counts when you're up against carbon frames that are 700+g lighter...

The Precision Billet/Paul's rear derailleur works surprisingly well when set up with 10s Campy shifters, but 9s Shimano cassette - especially when you take into account the fact that the carbon rings/ergal cassette have no shifting ramps or pins.

I don't think those 110g Tufos will ever get ridden on the road - I swopped them onto the bike when I arrived at the show. I would certainly love some recommendations for lightweight tubulars that are good for riding on the road (the best compromise for durability/puncture resistance against light weight)... I have some 150g Panaracers and have thought about some Veloflex or Tufo 160g tubs. How well does the Tufo sealant work?


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Location: New Mexico USA

by gandini

I have used both Tufo and Stans sealant in the Tufo S3 lite 215. Both work very well so long as you have enough, which does add weight (about 25g per tire unfortunately.) These goathead thorns Im talking about are the nastiest thing on the planet and the sealant is very effective against them. I have had small glass cuts that it seals also. The only time iti didnt work was when I got a 1.5 inch roofing nail in my tire and it ripped the sidewall out. At least I got to see how Tufos are made, since the tire was useless and i cut it open...


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by wishIwasSponsored

sorry wrong post

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by BeeBee30

I've always fancied one of those Precision Billet rear mechs, but could never find a short cage version, were they available or is yours a custom?
Ti or dye!

The Weenie formally known as CAADHEAD

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by jahknob

The Precision Billet RD is standard, except for the cage, which was made for me from aluminium by a local (retired) engineer, to my spec, and I had it anodized to make sure it would stand up to conditions on the road. Has worked out wonderfully, and with the weight now down to 150g (thanks to Speedware carbon jockey wheels), it's still pretty competitive without taking a dremel to it and making lots of holes (which I would do if I felt confident enough, or knew someone competent to do it - I have a few spare PB RDs for parts, but only the one short cage). I should add that the shifting, with Ergo levers (10-speed) and HG-compatible (9-speed) cassette is pretty good. If I was a sprinter I might wish for a slightly more positive shift, but I can happily live with the split-second lag that is the result of such a mixed-up combination.

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by Sprinter

Hi Jahnob,

I found your bike on another site a while back - the Roberts site? - and saw that you were very pleased with the S&S couplings, so I passed the idea on to a magazine called Wallpaper and they used the idea for their 'bike of the year' - which is a Seven mtb - chopped and joined with the couplings...just thought you might like to know what great influence your bike is having - it's already led to the making of a 'bike of the year'.

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by FreaK

Is this the lightest frame with S&S couplings do you think?
Most are on touring bikes to begin with.

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by jahknob

Hey FreaK,

In answer to your question, I believe that the ULT Roberts is not only the lightest bike with S&S Couplings, but in a broad sense is probably the lightest folding bike in the world (Obviously many fold smaller and faster, but they're usually built out of the same material as barbells and they handle like jelly!). The real beauty of the BTCs is that you don't know they're there until you need them - in every respect the bike handles like they don't exist.

I should probably submit the bike to the light bike sites and the relevant threads on this forum which have attempted to list the lightest bikes around, as I suspect it would probably sit happily near the top of the list. And it doesn't skimp on the shifting/wheel size etc.

And Sprinter - appreciate you letting me know about the Wallpaper Seven MTB and where the idea came from (it would have been on the S&S site that you would have seen the ULT or my other S&S Roberts - a Compact Audax Special, as the Roberts site redesign featuring the ULT Roberts isn't actually "live" yet). I make no bones about the fact that I am a fan of S&S Machine. The BTCs have allowed me to take a bike on family holidays that would not have been possible otherwise and go places to ride with much less hassle and cost in general.


Bring on 953!!!

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by ras11

That's an amazing bike. :thumbup:

BTW, I think the Ritchey Ti road breakaway frame come in at 1500g. I bet you could tune that down a bit. Those SS couplers adds a lot of weight, while the Ritchey design only claims to add 100g. I'm sure your claim about having the lightest complete bike is true. But that might not be the lightest frame.

Why steel?
:-) Toys-R-Us

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by jahknob

There were several reasons for steel.

One is that steel has become somewhat sidelined in weight-weeniedom, so it was an opportunity to bring it back into contention. You can easily calculate that by moving all the parts onto a CR-1 or 2006 Ghisallo, the bike goes from 5.5kg to something like 4.7kg (Tempting? - yes. Likely? Not unless I win the lottery)

It was an interesting joint project for Roberts Cycles and myself - I've had several of their frames over the years and I consider their work to be superb. I'm less convinced of Ti/carbon framebuilders' ability to provide a full custom service and a frame perfectly tuned to the individual at an affordable price. The ULT Roberts frame was totally made-to-measure with tubing choices to suit my purpose. (Again, maybe when I win the lottery, I'll set out to overturn this bias against custom Ti/carbon).

The frame was never meant to be the lightest (being steel, how could it be?), but I did do some research with S&S machine about the suitability of different materials for their BTCs before embarking on the project. Carbon is a no-no (though Calfee use BTCs on Ti tubes bonded to the carbon), Ti needs to have fairly substantial tube thicknesses, so only plain gauge Ti frames suitable (so no BTCs on a Ghisallo...), whereas with steel any of the lightest tubesets would still work OK, giving full rein to customisation of the tubeset for best ride quality. As it happens, the frame could have been a bit lighter, but for a problem lining up a different (lighter) carbon rear end with the frame geometry in this case. I've never quite managed to figure out to my satisfaction what the BTCs add to the frame weight - somewhere around 200g, depending on the weight of tubing removed...

The new Ritchey Ti/Carbon breakaway is listed as 1520g in 58cm size. Notwithstanding that the official weights nearly always turn out to be underestimates, it's almost £2000 for a stock frame, fork, headset and cable splitters, versus around £1600 for my full-custom equivalent (frame, fork, headset, BTCs, cable splitters, paint job) - and since my fork is almost 100g lighter than theirs, that's an equivalent weight with a lot more for less money...

Also, the beauty of steel is that it is repairable - maybe not easily in the case of my ULT frame, but it's nice to know that the investment is likely to last a lifetime (with the kind of mileage I'm likely to do on it!). In truth, if I could have a 2006 Ghisallo with BTCs, I'd take it. I love the ride of Ti best of all (fond memories of my Merlin Extralight - my first weight weenie project). I might even go for the Ghisallo without the couplings, but I would need to be rich(er)!


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