After a quick search I can’t seem to find the thread I had been using to post the updates for my current frame build in January, so as I’m now back home and getting on with the building again I will start a new thread…

for all previous updates… click here

for update number 7, where I have started making the swingarm – click here (sadly quite short)

I like the croc skin look!

Not entirely sure what you mean by croc skin look?

but another small update from today (Number 8 ) – here

nice work, if you need any more bits i’ve got a couple of frames that are heading to the scrap man. mail me if you want them
cheers
paul

ok update number 9 – to me it’s finally starting to look like a bike frame – although that could be the epoxy fumes!

Here 🙄

You’re mental.

Them epoxy fumes must be amazing 🙂

Love the madness of what your doing.

Max – #36er 😆

(for all those that don’t get that – check out max’s projects and his dual disc hub plans)

Are you making integrated light mounts?

I assume you’re only going to be riding that at night.

Give him chance to finish it before you judge it.

Once its cleaned up, sanded, lacquered etc it might be awesome

Everyone needs a hobby.

Personally, I’ve been enjoying reading about it for a while now. I’m looking forward to the next update

So update number 10 is here – CLICKY 😀

Bigjohn – I wasn’t planning on making integrated mounts 🙄 and the way I’m building this, the “make it look nice” part comes after I’ve done a bit of testing – as there is no point polishing/smoothing bits only to have to cut/redo it!

Looks good so far – are you fiberglassing the ali bits before wrapping with carbon?

Damascus, I’ve seen his homebrew hardtail. BigJohn has the right idea!

monkeyboyjc- yep, a thin wrap of fibreglass around aly bits under the carbon – which should hopefully stop galvanic corrosion (I think that’s how you spell it)

Nathan – 😥

ok next update is here – I got quite a lot done today and it’s really starting to look like a bike!

———-> Update 11 <———

I wish I could make bikes all day 🙁

Also, there is so much foam, forgot if you melt it out or not, do you? Will it add a lot of weight? To save weight I think you should drill random holes in all of the tubes.

I weighed the foam for the front triangle before adding the carbon, it was 170g so I melted it out, but for the swingarm the foam weighed 21g and the chainstays it weighed 12g so I’ll leave those in as not worth drilling holes to remove it!

As for my love of drillium, I think it would be to far to extend that to carbon!

Genius Max, what a great idea! Same for your 36er?

Everyone needs speed holes! Produces negative drag according to treks wind tunnel testing.

Finally got another update done – I made a bit of a major measurement mistake, making the chainstay length somewhere in the area of 465mm but now back on track (with more reasonable 430mm chainstays)

>>>>>>>>> PART 12 HERE <<<<<<<<

What is the approximate weight of the frame?

love it oliverracing,shed engineering is the future !

I’m aiming for a frame and shock weight of sub 2.5kg, 2.2kg is my target, but I know I’ll have to redo the swingarm to reach that.

keef – I hope to have this built up singlespeed for ssuk2014 (with a tensions/locked out mech)

Ok – update 13 is now done – looks like the frame will be complete by the end of the week!

——–> UPDATE 13 HERE <———

If there was ever a reason for a bloody like button….!

Absolutely tremendous work.

Epic!!

Good work, really enjoying reading this thread.

I have a couple of questions;

How do you know how much carbon fibre to use? Have you done some computer simulations? Or do you have a lot of experience so are confident with making an educated guess?

And how did you decide the suspension pivot locations? Copied from a bike with suspension characteristics you like? or again some sort of computer sims, or … something else ?

😯

jairaj – glad you’re enjoying it! now to answer your questions;

I have researched various homemade bikes to see how many layers that each of them used, also sheldon browns site has a carbon bike project on there which was useful to look at, as for computer simulations (FEA) I didn’t do any and I don’t have a huge amount of experience, so I’m just using my best judgement on where I think needs extra strength and where can do without.

For the suspension design I bought Linkage X3 software (about £15 if I remember rightly), it was well worth it as I have been able to calculate travel, leverage ratios and the overall side profile look of the bike. I have roughly copied a 2009 scott sparks geometry but have used elements of the rocky mount element from around that period too, I have also made a few modifications to suit the parts I have. I also used NX8.5 to do the final details in the design.

there is a little bit more info in the designing in part 1 + 2

I admire your balls 🙂 ( bike building ones that is ) !

Regarding how much carbon to use, it’s easy, you just put way too much on. I don’t think Oliver is trying to make the lightest frame available (but correct me if I’m wrong), just a frame that works. That’s how I did mine. If you look at a ‘real’ frame, the wall thickness is maybe 1mm. My theory was make it 2mm and it should be strong enough, and I was right.

richmars – I am aiming for as light a possible but also want it to be strong enough for racing, but I’m aware for the Scott spark the frame and shock weights are about 1850g so I feel 2220-2500g is an ambitious but realistic target. I do plan on remaking the swingarm a bit lighter in the future to knock some weight off it.

How do you melt the foam out? With a heat gun, conducting rods or chemically? Can an idiot do this? I’m an idiot and I’d like to.

Really interesting work there mate, you speak in your blog of a hardtail, do you have a build thread for that too?
What sort of carbon/resin are you using? Is it PrePreg?

thestabilizer – I remove as much as I can but attaching a 400mm metal rod into a drill which removes 90% then a bit of acetone disolves the rest.

Chrishc777 – I have done a bit of a build blog for the hardtail ( can’t seem to link but click 2013 on the right side of blog) but sadly I didn’t take that many photos, hence why I’m doing so many this time! I use dry cloth with quite a slow set epoxy resin (20-30 hours)

Oliver,
Based on my huge experience of making carbon frames (!) I would say make the first one well over engineered. Ride it hard and see where it breaks. Then improve things on the second. I would say that the hard bit to get right is the metal to carbon interfaces. You need a mechanical joint (a feature in the Al) that the carbon can grip onto, not just the adhesive joint. But it looks good so far!

yep – that’s how I’ve been working, my hardtail has held together well, apart from the bb debonding but that was due to an error when building it. I plan on testing it to destruction (or not) and if parts fail I’ll beef up v2 and if not I’ll lighten up v2!

For the alu-carbon interface, I am drilling holes in the surface to get a better grip, if this fails I’ll use small mechanical fasteners with the join.

What sort of weight fabric is it? and what resin system?

Good work! How smooth do you expect the final finish to be?

chrishc777 – oops – I had edited the previous reply to add that but obviously missed the 15 minute cutoff, the majority of the fabric is about 300gm 1×1 weave – as I was donated a lot of this for a school project and I still have some left over. I also have some 650gm twill weave(also donated for the school project) which I use for making flat sheets and a small amount 165gm twill weave(yep you guessed it – donated too 😀 ) which I use for the smaller parts.

I use the Easy composites EL2 resin system – I have only got the slow hardener left so using that up but would probably buy the fast hardener next time.

Cheezpleez – I hope to get it to a reasonably smooth finish, but it will not be a factory quality finish as that would take days of sanding – just smooth enough to look finished and less of a work in progress.