Sub 5Kg bike, Advice needed. (UPDATE: First parts ordered)

[aerobikewheels]

Dear Weightweenies,

I have been following this forum since a while and when searching for detailed information somehow this forum always provided good input, because when someone ha san opinion about a product, the next persons will quite possible disagree and explain why. Which gives me a good view about a product.

Problem is. When you are looking for building up a bicycle. and want every component to be perfect its hard to "see the Wood for the Trees". I lost the oversight.

That's why i am turning to you guys,

What's my goal?

A sub 5Kg bike, Included pedals, bidon cage's, numberplate holder, the lot. Without crazy weight limits. I want a fully functionable racebike i can trust while descending.

What's the budget?

I don't want to spend an extreme amount of money, i see and fully understand that this kind of bike will cost me serious money, But brands as AX lightness are money-wise out of the question. I am not going to put a speciffic price tag on the bike, but paying 300USD for a stem or seatpost is out of the question.

What are the demands?
A race bike mainly used when in the mountains, it wont be my main bike, as i have a wheel building business, it will be in the showroom for the majority of the time. It should be a fullblood racer tough, The fact that i am not going to use it in many races shouldn't mean it is not made for that.

Lightweight is nice, but performance shouldn't suffer, the weight bennifit should be an advantage, so no weight savings at any costs.

Every gram counts, Changing bolts, derailleur wheels, lightweight spacers, won't affect ride quality but will improve weights. I might be able to make the last savings to reach my goal by doing this. Suggestions are welcome.

What do i already have
Frame and Wheels are already decided.

I have visited a major bicycle manufacturer which produced mainly for a huge brand (rode tdf this year) i had to sign a contract to keep my mouth shut. But this factory also makes some nice products they develope and sell to a brands to sell under own name, For those products i will just mention the weight. Pictures will follow. I tested some of them, and none of them has disappointed me yet. As much as i would like, i can't say anything about the origin. It is not the stuff you buy from aliexpress, as i think some open mold factories can offer excellent quality which can be of the same level i prefer this brand, as they shown me the production methods and how they test their products. I will just note them as Brand X.

p.s. Yeah, this factory was in asia, for those who want to know. The reason for the visit was because of ordering a whole lot of carbon rims for my wheelbuilding activities.

- Frameset: To be announced

- Wheelset 1: 900Grams
- 235Gram carbon tubular rims (minimal coating on request to save weight) 20mm depth)
- 20/24 spokes Sapim CX-Super spoke 3,6Gram + 3,2Gram nipples (total 172.48 Gram)
- 257 Gram hubs (bitex with ceramic bearings) I might be going for tune hubs, depends on the total prize

- Wheelset 2: Clincher wheelset, to be announced

(rim has 90kg weight limit) rest of the parts must have a weight limit above 100kg, So if i swap the wheels, bike will be suitable for almost any rider.

More info on those will follow tomorrow.


Some of the other parts i already have an idea, some parts i just don't know yet.

- Seatpost

-Must be 27,2mm
Brand X can supply me with a 135Gram seatpost

lighter suggestions are welcome

- Headset
Standard 1 1/2 bottom 1 1.8 top

As light as possible, Won't be willing to pay extra for ceramic, don't see the use in it for a headset.

- Handlebar
Brand X can supply me with a 180 Gram version
180 Gram

Lighter suggestions are welcome, also sub 300gram handlebar stem combinations.

- stem
Ritchey Wcs260 120mm 110Grams
Been using this one on my racebike, and i am happy with it, lighter options are welcome.

- Saddle
somewhere sub 150 gram. no idea yet

- Bidon Cages
18 Gram Brand X
Already using those, they clamp really well, are lightweight and over 1 year of road use and still working fine.

- Crankset
Help! i have no clue. I want to have the look zed crank, but that one does not fit. so need something else

- Chainrings
1 Set of Q-rings, 1 set of lightweight chainrings for the pictures
For the lightweight chainrings, please suggest.

- Brakes
Planet-X CNC (directly factory bought, but same as planet X)

- Casette
11 speed, And no aluminum. I want to be able to actually use them.
Don't bother with campa/shimano/sram compatibility, i am already using both shim and campa bodies, works perfectly fine and interchangeable, sizes seem within a hair, the same.

I was thinking of the Sram red casette. But lighter options not made of weak aluminum are welcome.

- Chain
Kmc x11sl?

Alternatives are welcome, don't want to spend more than 45 euro on a chain as i have to replace it often.

- shifters, front derailleur and rear derailleur
I put those together.

Mechanical Campa Super Record (2015) or
Sram Red

Not really sure, weight difference is marginal in favor of Sram, but i am a campy rider and perfectly happy with it.

- Cableset
No idea yet,
As light as possible, maybe titanium inner cables? no experience, so far just used stock campa/shimano

- Tires
Some lightweight tubes, Suggestions are welcome

- Pedals
Currently using spd-sl but thinking of switching,
Needs to be a fast click in system. And lightweight

----------------------------------------------

Small parts, bolts, Rim tape, Bar tape

Please suggestions on weight savings, from spacers to star nuts, top caps. Maybe someone knows a good company for titanium bolts.



For now i will call it a night, tomorrow i will do some more investigation on it, and find some weights.

I hope to learn from your experience, Thanks.

[bm0p700f]

sub 5kg bikes have been done a sub 6kg disc brake road bike is my WW challenge and the more I think about it the more a challenge it becomes. Will a 20mm deep carbon wheelset built with sapim super spokes really be stiff enough for climbing. All sub 5kg build need a fair spend.

Campagnolo Comp ultra chainset is pretty light but for really low weight THM clavicula but this require a huge spend. Extralight hubs are very light and they do 200g hubsets with normal flanges. All of this kit though is expensive.

Miche do a durable aluminium cassette at 132g.

Look at the extralite and FRM catalogue, they have some very light kit.

[milehighcyclist]

Good luck and keep us updated

[NoInterVention]

<5kg race weight + durable + non-premium price point = ...ambitious. But I hope you can pull it off! I like the idea of crowdsourcing the theorycrafting stage. I'm planning a more moderate ~6kg aero build and thinking about doing the same. I'll be watching this thread to get some ideas. Speaking of which..

Some ideas:

Saddle, seatpost - Smud I'm led to believe makes some nice lightweight components, including a ~70g saddle and ~100g 27.2 seatpost. Haven't tried their products myself but I've seen them suggested around the forums, and it's what I'm looking at for my own build.

Cables - I have no idea either... but here's an interesting review of a few different cable systems.

Pedals - Speedplay Zero Ti would probably be the go-to choice, especially if you can use a 4-bolt shoe. Then there's the more exotic options such as Aerolite or Ultralite (just linked both to Fairwheelbikes) although there's functional downsides to both those options.

Screws, small parts - depending on where you are in the world, check out torontocycles.com or r2-bike.com.

Good luck! Also, I'm very interested in seeing the parts from your mystery source...

[kramnnim]

Hollowgram crank if the frame is BB30/PF30...?

[TimmS]

Please look at some examples of light bikes around here.

Donalds and Fuchs bikes could be some inspiration for you how to build a light bike without the most exclusive parts, but with a lot of tuning.

I think you already made some well choices on wheels, frameset and groupset, but can improve on a lot of the other parts.

Seatpost
Do you need setback or not? Seatposts without setback can be found around 100g and cheap on ebay.

Handlebar
I think the only substantial lighter option is Schmolke or MCFK, both will cost you to much.
I have an old EC90 handlebar, stripped and with the ends cut off at 170g, but it is 26mm.

stem
Extralight is your only option I suppose. If you don't want to spend the monney, you can also look at the kalloy uno stem on ebay with a ti bolt upgrade or a syntace f99 stem if you go for 26mm handlebars.

Saddle
there are some aspide wannabes going around on ebay, around 76g for 50 dollars

Bidon Cages
tune wassertrager.

Crankset
Sram exogram if it is BB30, and probably also otherwise, stripped ofcouse.

Casette
You can try a sram red cassette at first, but I think you will need a aluminium cassette.

Pedals
Don't buy titanium pedals at first, go for chromo axles and upgrade those with titanium axles and bolts, saves you a lot of money!

[TimmS]

oops double post

[Martin1977]

Nice project, but from what I've read so far, this build is not going to be sub 5kg. As You mentioned, every gramm counts when You try to go sub 5kg. My bike is 4,86kg, but it has recon aluminium cassette and 2x Vittoria Crono tubulars. When I change cassette to Campagnolo SR and rear tire to Vittoria Corsa CX, bike is still just below 5kg, but with Berk combos, AX brakes, Clavicula, Fibrelyte ...
Check my bike and buildlist with weights. All the components have weight limit > 100kg. You did not mention frame, but other components are heavier than mine, so my guess is, that the bike will be heavier than 5kg.

and my advise: if you want durable wheels, avoid superspoke or Ti spokes. Build wheels with CX-ray and avoid problems with lack of stiffness and breaking spokes.

Good luck and keep us updated about the components and build progress

Martin

[aerobikewheels]

and my advise: if you want durable wheels, avoid superspoke or Ti spokes. Build wheels with CX-ray and avoid problems with lack of stiffness and breaking spokes.

Martin

I see you used those spokes on your own wheels, the non aero versions,

Can i ask you whast problems you experienced, what spoke tensions did you use, and where did the spokes snap, (middle or the bending at the end).

I am 67KG, and never broke a single spoke. altough the miles i have put on superspokes are very limited and only for testing.

At the moment i have one client using them. he is 78KG, not really a heavyweight. it is a recreational cclist, but he is happy with them. I really want to give them a try. but please tell me your experience?

Further. Thanks, i am overwhelmed by all the suggestions already, i had a busy day and tomorrow will be also busy.

First component i am really looking to decide is the crankset.

As i mentioned i wanted to be able to put rotor rings on them. The SISL2 seems no option anymore.
The problem is, i overlooked this crank but i found it and fell in love with it, the weight is stunning, as i can find, so is the stiffness. And the design is functional and beautiful to look at in the same time.

only question is now, will i take a 34/50 or a 39/53 crank.

I am perfectly happy with my 40/53 rotor blades i am currently using, Altough i use a 29tooth when going into the mountains, and i am not affraid to use it, to keep an accepteable pace.

I assume the 34/50 is slightly lighter and 50 - 11 should be heavy enough for me in sprints, as i am not a real sprinter.

For casette i will have to remain at a 11-27 or even 11-29 because otherwise i would have a gap in available gears.

someone else switched from 39/53 to a compact and what are your experiences?

for the clavucia crank, i know it is a phenomenal crank, but i don't like the looks of it, the cnc machined aluminum looks awesome to me.

a third option would be the gravitas 3.0 crankset, wich looks amazing at first sight, but some of the design seemed to be focussed rather on looks than actual function. Adding to that the fact that you can order the crank and possibly wait for half a year to recieve it pts it off the table.

Crank will be first decission i make, and as it is a part wich is important for good performance, i am willing to spend some cash on this one.

[TimmS]

Hollowgram, Clavicula and Gravitas are all in the more expensive region of cranksets.

If you don't want to spend an extreme amount of money just buy a sram red exogram crank...

[bfno]

Cant see a 'cheap' bike coming in under 5kg, under 6 is almost achievable depending on the depth of your pockets. I will be interested to see the frame choice I wish you good luck

[Martin1977]

So You are much lighter than me. I'm 90kg and during winter 95kg. Anyway, I broke spoke about 2-3 times a year. All of them snaped at hub. After I replaced spokes in rear wheet to CX Ray, I also noticed higher stiffness of my bike at BB area. So I would not recomend these spokes to any heavier rider.
Maybe with Your weight, they will be OK, but if You want solid and stiff wheels, I recomend you to use CX Ray.

[aerobikewheels]

So You are much lighter than me. I'm 90kg and during winter 95kg. Anyway, I broke spoke about 2-3 times a year. All of them snaped at hub. After I replaced spokes in rear wheet to CX Ray, I also noticed higher stiffness of my bike at BB area. So I would not recomend these spokes to any heavier rider.
Maybe with Your weight, they will be OK, but if You want solid and stiff wheels, I recomend you to use CX Ray.

I am thinking about the following solution,

use Sapim CX-ray spokes at the drive side of the rear wheel, and use the super spokes for front and nondrive side, This way there is a marginal weight gain, but the spokes wich have the highest load are the stronger CX-ray's.

I saw this solution passing by sometimes, i never tried it myself, and this might be a nice way to test.
Worse case scenario is that i would have to respoke the wheels with CX-ray's, i don't want to compromise quality so if i will experience same problems that will be the solution.

For my budget.
i haven't set a maximum budget. but it will look at what the costs for each gram are.

For example, if i have a Ritchey stem of 70euro 120mm measuring 110 Gram and i can even save on that with replacing bolts for titanium. so lets say we bring the weight down to about 100 grams (maybe a little more) and costs of titanium bolts are let's say 30 euro's. the total costs will be 100 euro's.

Compare that to, for example a mcfk stem of 120mm wich will cost me 350 euro's there is a pricedifference of 250 euro's (i assume mcfk already has titanium bolts, correct me if i am wrong). So every gram i save will cost me 25 euro.

For the crankset, i can get a new, complete hollowgram crankset for around 680euro's (included bearings). I found different weights online, but i think 480Gram's is the correct weight. comparing to the 580 gram's of the sram crankset. is a difference of 100 gram's. and included bearings this will cost me 300 so a price difference of 380 euro's. So each gram will only cost me 3,8 euro. Wich is far more attractive.

Honesty be said, i expected the sram crank to be more expensive, more like campagnolo pricepoint. So i will keep this crank as a backup.

Hollowgram crank if the frame is BB30/PF30...?

Probably will be

For the seatpost, i checked. The weight of 135 gram is for a 31,8mm version not the 27,2, i assume this will be lighter, i asked for the weight, have yet to recieve an awnser. Construction looks the same as the schmolke SL, there is no weight limit. so i assume till 100kg will be fine, i asked to confirm. the price is much lower than these super lightweight brands, so for the savings you will be above 20 euro per gram. so this will be same story as stem.
EDIT: i also think 300mm will be enough, so this will also save a few grams.

EDIT: 14:34
http://www.starbike.com/en/tufo-elite-jet/

I have ridden tufo's, not these and i like the tire's.
Any experience with these tubulars?

[aerobikewheels]

I am very busy with a list of components wich will be around 5Kg to shoot at, and with known weights, so if anyone has an alternative. It will be easy to see if it saves weight. I hope to have it online in the late evening.


Further, i just tought of something , and please do correct me when i am wrong.
when the stem is tightened. wouldnt it be possible to remove the starnut/innerclamp alltogether. And make a simple cap (a cutout flat carbon plate, with some foam glued at the bottem so it will clamp and stay in place, to remove it you will just have to place your nail inbetween and whip it out), like a bar tape plug to close the gap at the front, as i dont want to use a starnut in my fork as it might damage the carbon, and the lightest solution without a star nut i could find was around 27 gram. A plastic plug to seal the gap would be around 5 gram. and it won't affect ride quality in any way. only if you want to remove play you have to place a temporary top cap to tighten. but when the stem is clamped it can't move anymore and it will become useless.

[aerobikewheels]

Hereby my first weight table. It might not be 100% accurate. But please take a look at it.

http://www.filedropper.com/weightlisting