Just at lockdown, I found a crack on the seat tube, top tube junction on my Cannondale F29 alloy frame. Dealing through lockdown and the bike shop I purchased from, amazing that I was sent a replacement frame under warranty withing 2 weeks. This appeared the beginning of June. Built up the same day and chuffed and thankful for being able to ride this bike while on Furlough. Riding XC , which is what I do and nothing gnar !. So, having issues again with creaks and found the cassette slightly loose and pedals needing a tweek for play and seemed to be fine. Slight creak again this morning on a ride, so thought I would check the cassette lockring again tonight and then notice a small hairline crack on a weld between the seat post tube and side of the top tube. Slightly different to the last frame. But similar noises while pedalling. Lick a tick noise.
I have emailed the bike shop again, but not sure if I am going to be doing this again soon, so weighing up my options on a frame change.
I built a dt swiss rear wheel, so can re use this as currently QR and just need adaptors. Running 3 by at the moment , as old skool. But the main problem is I like the lefty fork and want to reuse this .
Questions
1/ I believe there is a system for fitting a lefty to a standard headtubed bike ?
2/ Would using a 90mm fork on an Ibis DV9 create issues ?
3/ Any frame recommendations I might want to consider similar to the Ibis ?
I understand I may have to change to 1 X . So, I can just buy a single chainring for my XT 8000 cranks , longer arm mech and a cassette.
Anything else I may need to consider ?
Being away from biking for 2 years , I have missed loads , so almost consider myself a newbie 🙂

We used to call Cannondale “Crackandfail”

Nice bikes though.

How much seatpost do you have inserted into the seat tube?

First frame was warrantied and was asked to send a photo of the seat tube in the frame. Was using a 400mm Thomson and I almost cant get anymore seatpost into the frame as it hits the bottle bosses, so I would say plenty 🙂 Cannondale agreed the first time round and sent me the replacement.
Looking at this one is 10 weeks old. Shame really, as its a fab XC bike . Riding my Jekyll today and adding 50% bike weight and 26 er with fat tyres did feel a drag but was still fun. May stick with that for a while……….
Still like the Ibis frame but may involve more costs than I would hope for currently………

https://cannondale.zendesk.com/hc/en-us/articles/219101027-Can-I-put-a-Lefty-on-a-non-Cannondale-bike-

£90

Cannondale Lefty-4-All 1-1/8" and Tapered Steerer KH106

Shame bout Cannons

i liked those ELO Leftys bitd – mmmmm lust