The Golden Boy 

Does the are of the BB where the SN is... does that area look patched or goofy to you? Not just the finish; I mean the metal.

The one photo sort of makes it look like there's a patch or spackle or something on the shell and the number stamped into that.

With no ribs, and Suntour dropouts and 44 cm chainstays... does that point to a TX200 or 300? or a TX700 or 710 with Suntour dropouts?

Heck, if there wasn't a SN, you can just say it's an employee frame... this is goofy with the weird numbers on it.

tarsi 

That photo was between repaint and powder coating. After powder coating a rubbed out area where numbers should be is more noticeable.

Who knows? Have to catch a flight. Thanks everybody!

tarsi 

Any photos of TX200 or 300's out there?

JunkYardBike

Sorry, fixed it.

jpaschall

Just googling on the forums I found a 78 TX300 with the same cable guide on the DS chainstay, but a stamped crown, 77 TX300 with the same cable guide but no pic of the fork crown. I’m thinking the fork crown points away from these lesser models.

tarsi 

Wow, looks like an exact match. Do you know if your steer tube has ribs on the inside?

JunkYardBike

I have fenders installed, so I can't get a good photo, but the steerer definitely has the straight ridges indicative of Ishiwata 022 tubing.

JohnDThompson 

That's the wrong end of the steer tube. Ribs, if any are present, will be found at the fork crown end of the steer tube.

Sorry, I should have been more specific.

tarsi 

Ok, I removed the fork and...

a) no stamp present on the steerer tube
b) no ribs visible on the inside of tube from the fork crown end

tarsi 

I then examined a confirmed 1981 610 fork and found...

a) Ishiwata stamp on outside
b) no ribs on the inside (what?)

So without a Reynolds or Columbus stamp, it looks like lack of ribs doesn't necessarily rule out Ishiwata, right?

JunkYardBike

It's a difference between Ishiwata 022 and high-tensile Ishiwata.

JohnDThompson 

Lack of six straight ribs rules out an Ishiwata 022 steer tube, but other Ishiwata steer tubes, e.g. 025 were not ribbed.

And the Ishiwata stamp on the steer tube may just mean the fork was brazed by Ishiwata, using whatever tubing the customer specified for the fork. Tange-marked forks can also be this way.

tarsi 

Thanks John. So the absence of ribs leaves us with either Ishiwata 025 or Reynolds tubing for the fork, correct? Given the fork crown, is it safe to assume that most likely it's Reynolds tubing? Taking that one step further, if it's Reynolds tubing then is it safe to assume it's a 7nn (like you originally surmised) with Suntour drop-outs?

To me it doesn't matter what the model/tubing etc turn out to be, I just love a good mystery and can't stop until this one is solved. Have you ever seen a serial number like mine? Like I said, it looks like the originally stamped number might have been covered/filed and a new number stamped instead. The new number is a different orientation, font and spacing and doesn't follow the standard format other than perhaps starting with an H for a 710. Any idea how this might have come about?

JohnDThompson 

Perhaps the fork isn't original to the frame? The SunTour dropouts may have been a substitution for a shortage of Campagnolo dropouts. I don't specifically recall this having been done, but I do know Shimano SF dropouts were substituted for Campagnolo 1010 dropouts when the 1010s ran short, and Campagnolo 1010B dropouts were substituted for Shimano UF dropouts when we started seeing breakage problems with the UF dropouts.

tarsi 

Any theories on what might be going on with the serial number(s)?

tarsi 

Ok, strongly leaning towards this theory at this point. Given all the facts, I'm thinking a 536 frame with a 7nn fork.

Detail Recap

FRAME
Suntour Drops (consistent with 500 series)
Cable Stop (consistent with 500 series)
Headset not original 600EX as expected (perhaps original was damaged or replaced when fork was swapped?)

FORK
No visible ribs from crown end (consistent with 7nn/Reynolds fork)

Does this make sense?

Assuming it does, this might help explain the odd serial number. Perhaps with the fork swap the original 536 serial was filled/filed down and a new number stamped. Although new number doesn't follow TREKs convention it does start with an H which is consistent with the 7nn model and would make sense if a 7nn fork was introduced.

I know, alot of assumptions, but if this is actually what happened, what would have been involved in stamping a new serial number and who most likely would have done it? Would it be TREK, a LBS, an owner or ???

tarsi 

The 1978 catalogue doesn't mention the TX500 but the '76 and '77 both say the TX500 should have the Forged semisloping Cinelli type crown not the Haden Europa like ours. The only mention of the Hayden Europa crown are on the the '76 TX700 and the '81 710. The screwed head badges rule out an '81 model.

Strange....

tarsi 

What size wheels does yours take?

700c appear a tad too small on the front. Even with the pads slid all the way down on the Shimano 600ex brakes they only catch about 3/4 of the rim. The back pads align perfectly with the rim.

JunkYardBike

I assume the frame was built for 27". I've got long reach Tektro 55-73mm calipers on front and back. They're probably at about 65mm in the front and 57mm on the rear.