Bamboo 2

[gecko76]

Well that didn't go so well. The frame is fine (the dropouts might be a fraction out but the rear wheel runs straight which is the main thing) but I'm done with Giant Conduct. Got it as a cheap way of upgrading to hydraulic brakes on the old bike and it was great (though limited space on the handlebars somewhat) but trying to fit new hoses last night was a right pain. Connecting the calipers was fine but couldn't get the nut to bite in the master cylinder bit because of the olive and despite being careful managed to chew up the threads. Grr.

So now looking for GRX or 4700 series Tiagra levers. And a thru axle the right length.

[gecko76]

Hang on a mo. In a stroke of genius born of desperation it occurred to me today that the old hoses (obviously) fit and could possible be reused. An hour of fettling later (internal routing innit) and they're in, with new olives etc at the caliper end. The proof will be in the bleeding, a job I've never really felt comfortable with. The learning curve is steep on this one.

[gecko76]

Yep, that worked. Took it for a quick ride last night and no crackage so we'll call that a win. Bars are lower than I'd like, partly due to the shortened hoses, so I've got some Tiagra 4720 levers on order from eBay which will be fitted in due course. Let the sanding and oiling commence.

[gecko76]

Right, so, it's not that I've been idle but for one reason and another the build has been a bit difficult. Gears. I'm good at gears. I can do gears, but somehow this time they just wouldn't. Came back to it later, complete strip and clean and OK, now we're good. Brakes though. I thought I knew what I was doing but was completely flummoxed by not being able to get fluid into the system at all. Turned out somehow inserting the barb had ripped a strip of the hose liner and blocked it. That sorted, comedy moment ensued when pumping the syringe caused the plunger in the bleed cup at the other end to fly out, nearly hitting the ceiling. What else? Oh yeah, ordered the wrong thru axle assuming 142mm made sense (135mm for QR + 5mm for each dropout, no?) when in fact it needed 157.

It does line up though (well, almost - the rear wheel might be a couple of mm out of true which if I ever want to fit bigger tyres will be an issue) but it's built and while the hoses, and possibly steerer tube could do with shortening, once that's done I'll wrap the bars and then it's built and at just over 10.5kg I was a happy man.

Was. Taking it for a ride there was an unmistakable knocking/grinding which I was hoping might just be the seat post slipping so added some carbon paste and took it out again and this time the problem was clear.

Yep, that's the bamboo having sheared completely where it's bonded into the top of the bottom bracket junction. Reckon it happened going over a speed bump two weeks ago on its first time out. Glad to have it happen now rather than later but now what to do?
1. Contact the company and ask for advice.
2. Wrap it in carbon fibre tow and epoxy and hope for the best.
3. Remove that section of bamboo completely and bond in a length of 31.8mm diameter carbon fibre tube (ideally with enough space internally to fit a 27.2mm dropper).
4. Other (answers below).

[Lazarus]

Annoying and your thread has somewhat dampened my enthusiasm for building
1 then 3 followed by 2. *


* possibly use a steel sheath but it will look poor and add weight

Like this but not alluminium
https://www.ebay.co.uk/itm/171269222696 ... d_source=1

[gecko76]

That's not a bad shout. Clearly the bottom bracket area is where most stress is applied, so in a way it's not surprising that it failed there (I was expecting the seat stays might be a problem, which they still might be).

I'm not averse to adding weight for guaranteed strength. Being philosophical it's just another stage to the build, which continues to be an enjoyable process. It's not been quite as simple as expected, but if what I end up with is a hybrid of the two approaches so be it.

In that frame of mind, I'm tempted to liberally wrap it in duct tape temporarily and take it out tonight for BaM. That'd be silly though, right?

[Lazarus]

Madness you would need to brace it with something suitsmable like tyre levers before it would be a suitable bodge

One of those you were riding it like that anyway but clearly its a risk....your call but i would not if i had another bike

[gecko76]

Yeah, I'll nick my wife's bike. It's got a motor and everything

[fatbikephil]

I was about to say 'looking good, gecko' until I saw the sheared tube....
Seems a classic stress raiser induced fracture but I'd have thought that the bamboo would deal with that fine.

Be interested to see what BBC say, it would be a bit of a shame to have to use the dreaded carbon. Maybe grind away more of the alloy lug so no sharp edge where the tube goes in?

Keep at it!

[gecko76]

Cheers Phil. Advice from the supplier is to either add a layer of flax or carbon around the break to reinforce it, or do a rebuild on the front triangle. They’ve not seen this happen before incidentally, and it’s entirely possible I was insufficiently careful with my cutting/shaving of the bamboo and introduced stress risers by cutting too deeply.

At any rate I’m inclined to wrap every joint, for peace of mind’s sake, and hopefully that way it’ll last ten years.

(The advice on the jig was to use sandpaper by the way, which seems obvious now, and they offered to send a replacement.)

[gecko76]

Anyone used this stuff? Asking for a friend.

(Had some Fibrefix on order but it got cancelled)

[redefined_cycles]

Anyone used this stuff? Asking for a friend.

(Had some Fibrefix on order but it got cancelled)

It's utter sub standard. I don't usually use poor language but this crap is proper snake oil. Worked for me on something that looks like in the picture, for maybe half a day. Avoid. Didn't make me mad cos I was already at the limits of desperation.

Avoid I think I had bits of the packet flying about the car for months after as I thought maybe I'll take em for a drive to reduce wastage (of not having passengers and hurting the ozone).

[gecko76]

Ha! Thanks Shaf. I've been put onto a guy in Stirling who's very good with cf so will go down that route.

Been watching how the Athertons make their bikes, and am also feeling a bit sub standard lol

[redefined_cycles]

Ha! Thanks Shaf. I've been put onto a guy in Stirling who's very good with cf so will go down that route.

Been watching how the Athertons make their bikes, and am also feeling a bit sub standard lol

Nah, you're doing very good there. My bike mechanic used to p me about. Partly cos he probably got complacent with me being a regular and changing frames every year. The P that he took and I caught him out, he then allowed me to do work exp at his place so I could do my own thing and not be reliant on him.

Then I got better at building wheels than him (cos I read the book, he probably didn't) and the rest is history. IMHO, bikes should 'be able to be' fettled by most people. I'm hoping to teach my little one the art of wheel building soon which he'll love.

Then som carbon forks repair when Postie Rich sends me some lovely Traverse Prongs that have enough rub at the front that they could probably do with a Shimano fishing line repair kit using on em. What you do with bamboo all goes over my head, too much depth

Keep at it, we'll all be riding Gecko Bamboo frames one day

[redefined_cycles]

Oh, and them Athertons. They're just special

[gecko76]

[gecko76]

[gecko76]

The epoxy was still tacky yesterday (cold shed) but it's hardened nicely now. Think I'll leave it like this.

Tempted to do the seatstays too, to be on the safe side, but might use cf weave for that.

[Lazarus]

Nice to see you did not sacrifce aesthetics to get a good wrap

Firmly refuses to show his repair to his carbon frame

Hopefully its fully sorted now

[gecko76]

The weave was left over from bamboobike1. Hoping it's done the trick.

[fatbikephil]

Nice work that
Your challenge is to do a similar repair out in the sticks somewhere

[gecko76]

Touch wood that won't be necessary.

[Bearlegged]

out in the sticks

[fatbikephil]

Oh dear....
apologies all!

[gecko76]

If it were done when 'tis done, then 'twere well it were done quickly.

Don't know why I always feel the need to rush with epoxy but I do, and the result this time was a bit messier than hoped for, but it'll hopefully add some protection in the event of a crash or whatever.

This batch (on the left) was still a bit soft after 48 hours but after another day it had hardened properly, enough to risk building her up and taking her out (yes, 'her'. I live with five sisters and know whereof I speak). Nervous though, a bit like after a broken leg or bout of depression when you don't want to risk a regression but wih no creaking or cracking I think we're finally good.

Still need to apply tung oil, attach bottle mounts (very tempting to fit the rivnuts supplied with the kit but No Drilling) and the head badge. Will take her out for a proper ride at the weekend and if that goes well we'll be ready for NAWE.