cycleheimer

Has anybody had long-term experience with older Trek frames that used investment-cast lugs? I was looking at the seat cluster on one, specifically where the seat stays come into it. Looks beautiful, but will this thing hold up over the long haul?

OldsCOOL

I have never heard of a problem as long as they were under normal and expected use. I have loved, appreciated and used the Treks with IC frames for 12 seasons.

Can you share more about your bike in question?

The Golden Boy 

If you figure Trek started using that style of lug socket things on most bikes in 1985... if there were any sort of trend of them failing- you'd see it after 30 years. Unlike the Ishiwata cast fork crowns on Trek's 600 series bikes from the early/mid 80s. Those definitely did have problems.

The most I've heard about the investment cast pieces is that there are those who feel that it takes "craftsmanship" out of the building process. *shrug*

Chrome Molly

They hold up just fine. Where they were used on the seat cluster, I think they look rather nice in an 80's sort of way. That's always a location where builders have to do something to make it all come together.

unworthy1

I bet John Thompson could tell you for sure (former Trek employee), but I tend to support the idea that they are very robust.

JohnDThompson 

I left Trek in 1986, when the lugs had been in use for a couple years (they were phased in starting with the high-end models, and the version used on the model 360 pictured above was slightly different than the ones used on the high end models), but I was Trek's Warranty Inspector at that time and don't recall any particular problems.

rando_couche

IIRC, the whole rationale for those (as with most bike biz "improvements") was to speed up the production process, not for any functional improvement. Did I remember that right?

SP
OC, OR

Darth Lefty 

That is a functional improvement. It makes your bike cost less.

rando_couche

In theory, anyway... I don't remember Trek's prices going DOWN in '85 (and I worked at a Trek dealer at the time).

SP
OC, OR

unworthy1

It makes your bike cost less TO MANUFACTURE...FIFY
So Trek is "positioned to leverage" those increased profits to acquire stuff...like say Bontrager, Klein and Gary Fisher.
THAT's "investment casting" of a sort...

Darth Lefty 

Hoho yes ok very droll. Prices do go up, but not as fast as they should from inflation and exchange rates, because there's competition between companies.

Trek doesn't always make a killing, either. I was just reading a thing about how their 1990's tandems went on clearance a few months after they went on sale, and stayed there for years until they ran out of frames.

himespau 

Well, it makes it cost less for Trek to produce it. For you at the store, maybe not.

Edit:Tried to post but then my internet cut out for half an hour, came back and found someone had beat me too it.

SJX426 

The seat stay attachment of brazing to the seat lug on the sides was always a curiosity to me. I is the only place where the "tube" attachment has a shear loading. This design, like all "fast back" configurations, put the seat stay in compression at the joint. Makes a lot more sense to me, from a structural integrity perspective.

Also, you are less likely to pop a seat stay when trying to remove a bonded seat post by using the frame as a lever. So you might be able to apply more torque before you pull out the hack saw!

JohnDThompson 

Yes. The socketed seat stay end at the seat lug meant no need to braze a cap over the stay end and file flush to the stay before brazing to the seat lug. And there was a shoulder inside the seat tube socket so the seat tube could be cut straight at a defined length to butt against that shoulder. No finishing required on the top of the seat lug. The version used on the lower end models (pictured above in the OP's post) also had a shoulder cast into the top tube socket (as did the top tube socket on the corresponding head lug), so the top tube need not be mitered -- just cut straight at a defined angle and length to butt against these shoulders. And the socketed dropouts meant no need to radius and file the stay ends at the dropouts: just cut it off straight and braze it in.

The irony is that Trek invested in the tooling to make all these pieces just as steel frames were passing out of fashion, so I don't know if the labor savings ever amounted to enough to recoup the cost of the tooling.

dddd

Trek advertised that these lugs strengthened and stiffened the frame. I think that they were very reliable, and the cost-savings that they offered lent itself particularly well to very large-scale production.

Perhaps there was some weight penalty? They certainly have some things in common with other styles of cast tube end fitments, but would seem to further cut down on the number of brazing operations per frame.

I still come across quite a few Trek MTB's with the cast seat cluster, typically with a QR lever clamping the seat post.

And am I the only one that has found that cast seat clusters on a road bike seem to require a bit of extra torque on the pinch bolt to secure the post?

JohnDThompson 

Yes, they do. And the investment cast dropouts are considerably tougher to align, as well.

irwin7638

I've been using mine since I bought it in '87, no problems with the frame at all.

Marc