Now this is annoying-2nd cracked seatmast

[AndySV1K]

Is this a particular problem with proflex's

Im about to buy a seat post mounted luggage rack, but talk of stress cracks make me worry!

Is the added weight of luggage (full load with added tent and sleeping bag for longer touring) going to cause problems with the frame?

Andy.

[orange]

as I say - never caused me a problem with child seat and child on the back of mine. Maybe I was lucky...

[whisperdancer]

Whisperdancer,
I like that Look post you have. I do like the feel of carbon.

Terry

Thank you Terry.
When I looked at it for the first time, I only thought of change it for another one, as I always thought about one with a setback that, after all, wasn't necessary.
But now I like it very much and it looks really good on the bike, with that mate finish it has.

[shovelon]

Is this a particular problem with proflex's

Im about to buy a seat post mounted luggage rack, but talk of stress cracks make me worry!

Is the added weight of luggage (full load with added tent and sleeping bag for longer touring) going to cause problems with the frame?

Andy.

I think it has something to do with those blocks in combination with a REALLY flexy seatpost. I used to pull a hitchhiker and my daughter mounted to my 97 beast with no problems. But the beast had no blocks, and I used a Thompson elite seatpost.

Terry

[Colin]

Is this a particular problem with proflex's

Im about to buy a seat post mounted luggage rack, but talk of stress cracks make me worry!

Is the added weight of luggage (full load with added tent and sleeping bag for longer touring) going to cause problems with the frame?

Andy.

I use a Delta Post Porter on my XP-X (with bottle mount blocks and original Aly post) and it's been fine for 10 Years, see my gallery piccies.




http://www.discountbicycles.co.uk/biz/product.php?xProd=4645

I used it everyday to work on tarmac and several times a year on week long off road expeditions with two small (actually front) panniers and a top box bag. Probably up to 30lb in there all told. No sign of any probs...........

Col.

[shovelon]

Had time to get this done last night. No need to strip bike. Total time about one hour.


Cut off the blocks from on side and break off.

Groove out crack. See how block covered slot.

Lock mandrel and apply ground clamp on bare frame, not anywhere where current would have to go through bearings or gease.

Weld crack with full penetration to mandrel.

Remove mandrel. Brown heat mark shows weld penetration held flush to inside.

Check inside for full penetration. Incomplete penetration must be redone.

Smooth of weld with sander.

Sand off old block welds. Use schotchbrite pad to shield shock and buff.

Polish with knorristal, and reassemble. Let sit for 1 week to allow grain structure to reset via natural ageing.
 

[RhinoDave]

Dang... You make that look so easy.  Which I know it isn't. I can't weld anything.

[jeffhop]

jeez terry, im well impressed. i cant weld to save my life!!

[Willem]

Beautiful fix Terry.

I'm still amazed that K2 welded a fixed block on either side of a flex joint. Just by tightening the seatpost clamp the stress on the tube would be transferred away from the intended split.

Now why aren't you a full time frame builder?

[xp8-er]

i see the problem  and i think it is partly due to the blocks interfering with the degree of flex in the seat tube when you clamp the seat post.  The longer the split the more flexible the metal and the less likely you will exceed the elastic limit of the metal in that area.  On my xp8 frame the problem you have is less likely as my frame is a way large and the bottle mount  blocks are a lot lower and are no where near the split in the set tube. removing the blocks as you have done is the correct way to go and i think the quality of your work is excellent!!! 

[shovelon]

Now why aren't you a full time frame builder?

Uhhhh, did back in the early 90's. Company called Natural Dynamics contracted with us to assemble hardtail frames that had an arcing seat stay and bottom bracket. The idea was that while climbing, you could rotate the seat forward, and descending arc backwards. Actually it worked as promised, but the designer would not budge on rear suspension. So it ended up being just an overweight hardtail, that really never went anywhere.

Natural Dynamics closed their doors a couple of years later, but their work with ceramic-metal matrix aluminum was really fun. Stronger that steel, lighter than conventional alum, kind of like scandium alloy of today, it welded well, but was kind of messy. All the welds had to be ground down like all of the Cannondales of the day. PITA!!!!

Bob Girvin and his cohorts just amazed me. I can't hold a torch(pun) to what they did in the 90s. That and being an "American", I am not allowed to buy 7005 like China can. If I could, I would be building frames like a demon. The mindset is that I design, and sub the frames out to China. Bull-pucky on that.
The only way Easton will let me have 7005 is to buy from Nova Cycle supply. Conspiracy? Have you not noticed that all the boutique bulders are using 6061 and 4130 steels?

I would rather tinker and ride right now than have no time to ride. 

[kiwi]

wwhat are the neatly welded frmaes in the bckground....?Please dont tell me they are Terry,s modular shelves he knocked up with offcuts!

[shovelon]

wwhat are the neatly welded frmaes in the bckground....?Please dont tell me they are Terry,s modular shelves he knocked up with offcuts!

Ha!

Chuck Norris knocks up shelves!