Seat tube crack repair on XXTeam

[mixalive]

It is with a heavy heart that I make this post. But after the very first ride after purchasing my 95 XX Team in April 2011, I noticed the seat tube cracking. I immediately got off the bike and parked it. I was hopeful that possibly it was just a paint crack. The crack was initially about 11mm long. After a night of despair, and searching for a repair facility, I consulted with neo_pop_71 for his opinion. The next day, I decided to remove the paint on the crack to verify that it was indeed the aluminum that had cracked. To my surprise, the crack had doubled in length and began to split into a Y crack. I immediately took a 1/16” drill bit to the three ends of the crack. And yes, the crack was in the aluminum, but hadn’t made it thru to the inside of the tube.

[mixalive]

So, what we were looking at is a 7005 series double butted frame made in Taiwan for Barracuda. I made the decision to not only weld the crack, but to also press fit an insert into the seat tube to take the seat clamping stress off of the repair. I chose seamless 4130 Chrome Moly tubing as my insert material. Of course, using an insert into the seat tube necessitates going to a smaller diameter seat post, so I chose a Thomson Elite 25.4mm. The Thomson is extremely precise in its diameter from the bottom to the top. I sent the frame out for tig welding and the result came out great. He even ground down the welds for me. The bill was $85.00. I then reamed the frame seat tube so it would have a uniform diameter to about 8 inches deep. I ordered the proper 4130 Cromo from Aircraft Spruce and sent it out to a local machine shop to have the outside diameter machined to .05mm over the inside diameter of the frame seat tube. I froze the machined insert with dry ice and heated the inside of the frame seat tube with a heat gun and drove the insert with a shop press using Loctite Red 271 (initially as a lubricant and eventually to lock the insert in place).

[mixalive]

I was only able to get 5 inches of the 8 inch insert before the temperatures equalized and the insert/seat tube became one. I was able to perform the press operation without structurally damaging the frame under the press's 12 ton limit. After cutting off the excess insert and reaming the inside of the insert for a tight fit with the Thomason seat post, I re-created the clamp slot and finished the top of the tube. With everything assembled, it looks pretty good.

[mixalive]

Here is after a little painting. I was going to just touch it up but decided to paint the back half. I painted it with PPG Shopline Acrylic Enamel, single stage with hardener. I did not clear coat so it does not look as deep as the factory paint. It is a little dark but I think it will be fine.

Special thanks goes out to neo_pop_71 and his resources for all the advice and encouragement.

[neo_pop_71]

Thanks Mix for the nod but this resurrection is all you, my brother! It was great to share in helping you find your Holy Grail Barracuda, conversely I about died when you told me about the crack happening on your first ride... that must have been a sickening day! I give you all the props in the world man, you deserve it! You were the one that set about finding a solution, devising a plan of action, and the execution of said plan... that was all you! Let me say, you are a clever cat, I imagined it would end with a functioning frame but I never considered it would look cleanly done! No one would ever know after a bit of touch up paint.

You didn't have any background in a project like this, right?

Just to toss this out... have you considered some 4130 inserts for the headset? Given the track record of head tube stress cracks (remember Cudarider's A2M? As well as the Manitou frames, the Tomac hardtails, etc.), the big difference being you're staving off a critical problem as your head tube is intact and not in need of repairing.

Anyway Mix, I am very stoked for you... you've earned the right to ride that beauty! Maybe you should consider repairing other frames?!!! Ha! Just kidding my friend, now forget about the touch up paint and go hit the trail... a new maiden voyage! Enjoy!

-D-

[cudarider1]

Very impressive Mix, Great Job! If you have that shop press at your house you may have some people asking to ship you thier frames for repair. The whole heat and dry ice thing was a great idea and it looks really clean. If I didn't have the A2E already I would consider shipping you my A2M. I guess you could drop it to a 1 inch fork and work it the same way you did with your seatpost. Seriously impressive man! What did the fix cost you total with the materials and everything?

[mixalive]

A few images after the bike was built.

[cudarider1]

Definately a labor of love, that frame is worth saving, many years of use left in it now. Great Job!

[neo_pop_71]

The bottom line is that aluminum has a finite life.

Too true brother Mix! My buddy Ben, he's the wrench at my LBS, he basically said the exact same thing about the 7000 series aluminum to a customer who had asked him about why Santa Cruz changed their frame material. He said the Santa Cruz rep told him that they actually lost money for a spell because they had to warrantee so many frames. That's also why they discontinued using cast aluminum pieces in their suspension frames. If any of you have riding buddies that roll out on a Santa Cruz full suspension frame... don't follow too closely as you wouldn't want to be too close when the frame "taco'd"!!! Yikes!

[Mark]

Wow, awesome write-up! I could have sold you a spare XXTeam frame for $100, but it's much better for you to save the actual frame you love for sure.

Next, let's see a repair of the head tube, because I have a cracked one of those. lol