Rocky Mountain Cirrus 1992 project

[Chickenball]

Re:

Whatever you....do not use a shim for this bike. Be patient and get the proper 30.4 seatpost. A lot of them failed at the collar so getting the right post is a must!!! I had a Race Face but recently just sold it. Be patient as it will be sweet when its complete! Looks great!

 

[Minifreak]

Thanks RockiMtn, it is a real shame she's too big but I just love a project. I finally have time this evening to see my mate with a decent pillar drill to help me get the broken studs sorted

Chickenball, don't worry no shim here. Using the correct sized post even though not the Original Syncros.

Hoping to get this up for sale end of the week after a shake down ride tomorrow.

 

[syncrosfan]

Since the 30.4 Syncros seat-post is virtually unattainable, I was wondering why not buy the next size up (30.9) and ream the seat-tube to take that? You would be removing only 0.5mm off the seat-tube so I doubt that the tube will get weakened that much. There are a couple of 30.9 Syncros seat-posts knocking about (even older style ones).
An adjustable blade reamer and half an hour and some sweat and done.

 

[StealthDJ]

Before you go fully drilling the forks,

Take a torx key that would fit inside the outer diameter of the stud. Then find a drill bit that's smaller than the torx key. Drill (carefully) the bolt down the center, about 5mm. Hammer the torx key in (you probably won't need to use much force) and turn counter-clockwise to remove your sheared stud.

You might want to test the correct drill bit size for the torx key on a piece of scrap metal first, obviously. And while you're testing, have the fork part soaking in plusgas / wd-40, etc.

It's a trick that's worked for me on a number of occasions, but should that fail, find out the thread for the stud and find the correct drill size for cutting that thread (it'll be smaller - a 6mm bolt requires a 5mm drill, for example). Drill the remains of the bolt, being careful to keep everything central, then find a plug tap of the correct thread and run that down - you should have enough of the original thread left to get started and from there, the tap will happily remove the remains of the old stud.

 

[Chickenball]

Since the 30.4 Syncros seat-post is virtually unattainable, I was wondering why not buy the next size up (30.9) and ream the seat-tube to take that? You would be removing only 0.5mm off the seat-tube so I doubt that the tube will get weakened that much. There are a couple of 30.9 Syncros seat-posts knocking about (even older style ones).
An adjustable blade reamer and half an hour and some sweat and done.

Not sure about this, but may be something worth exploring. The seat tube collars were absolutely horrendous for cracking though. I think in Vancouver i've come across about a dozen of them and 8 of them have had a cracked seat collar (includes Experience's as well). I'm not a metallurgist/engineer but because these were done in the 90's when aluminum was probably not as pure, wouldn't it be worse and more prone to failure if you thinned it out? Or could it have been the same as the Alpinestars/Yeti ARC failures where headtubes and seat tubes cracked all the time?

 

[syncrosfan]

I'm fairly sure the cracking issue was due to the metallurgical issues of the 7000 series aluminum they were using back then, not so much the thickness of the tubes. That being said, when you ream out a seat-tube even with proper lubrication there will be some heat build-up in the tube and I don't know if that's something one would want to risk with those frames (it's a somewhat medieval process). If it were my personal frame I would try it out, if you intend to sell it, I would leave it unmolested (some collectors might frown upon modifying frames from their stock form). Leave it up to the buyer to see what he intends to do about the seat-post (and possibly pay the horrendous asking price for a 30.4 Syncros seat-post, we all know the asking price ain't gonna be pretty).

 

[Minifreak]

Thanks for more advice guys, I have some easy out type tools that I'm going to use in a similar fashion to the torch bit idea. The suggested drill size for the one I'm going to use is 2.5mm as want to be really careful.

Going to leave the post for the new owner to hunt down if they wish. The current post and saddle are the only non original parts but I don't think they look out of place.

 

[Minifreak]

Got them done



The offending items

 

[Chickenball]

I'm fairly sure the cracking issue was due to the metallurgical issues of the 7000 series aluminum they were using back then, not so much the thickness of the tubes. That being said, when you ream out a seat-tube even with proper lubrication there will be some heat build-up in the tube and I don't know if that's something one would want to risk with those frames (it's a somewhat medieval process). If it were my personal frame I would try it out, if you intend to sell it, I would leave it unmolested (some collectors might frown upon modifying frames from their stock form). Leave it up to the buyer to see what he intends to do about the seat-post (and possibly pay the horrendous asking price for a 30.4 Syncros seat-post, we all know the asking price ain't gonna be pretty).

Good call! It took me over a year to find the Syncros 1st gen post that's on my Experience. But I found a RF XY post about 2 months after I obtained the frame.

 

[Minifreak]

Ready in the early morning sun for today's ride