Trek 710 What Year?
 

Just got this today. Seller said it was a 1979 but although the serial number on the bottom bracket follows the LNLNLNN the numbers are not possible.

https://cimg1.ibsrv.net/gimg/bikefor...5ce37d4b6d.jpg

I've been studying the Trek Vintage website and pretty familiar with the serials and catalogs. Here is a pic of it. I used the crayon method to make it easier to read:

https://cimg1.ibsrv.net/gimg/bikefor...85c5580f97.png

It looks like: H?C3A26

According to Trek Vintage:

H = 710
? = The second letter could be a 3 (22.5"), 5 (25.5") or 6 (57.5cm Custom Size)
C = March
3 = The weird part is the year digit which I'm pretty sure is a "3" which would indicate '83, but it doesn't as this serial number format was no longer use since late '80. (I have an '80 410 that has a 000165 serial number.) Also, no color wrap around the seat tube
A26 = Probably run and number

There is also a "T" stamped above the serial...Is this the frame builder's initial?

So, here are some other things that help narrow down the year range:

• It's full Reynolds 531...the stickers are well worn on both seat tube and fork. Indicates a 710 which was available form '79 to '82
• Campagnolo Dropouts
• Head Badge is taped on not screwed on (late '79 and on)
• Trek Decals with out Color Wrap ('80 and earlier for the 7xx)
• There are some cool custom details like white paint filling the trek stamping on the stays and remnants of a outline/striping around the lugs.

History I got from Seller: Seller had it for about a year and had upgraded the components except for the crank and derailleurs which were original. He got it from a guy who flipped vintage bikes and that guy got it from the original owner.

I'm thinking a custom frame? Hence the oddities of the serial number? But from when???

Here's some additional photos:
https://cimg3.ibsrv.net/gimg/bikefor...5fa39f4be3.jpg
https://cimg4.ibsrv.net/gimg/bikefor...0f6faa12e6.jpg
https://cimg5.ibsrv.net/gimg/bikefor...242cdea3cd.jpg
https://cimg6.ibsrv.net/gimg/bikefor...c6a84ba72c.jpg

From my scouring, the year range I think we're looking at is 1979 to 1980--and you've already narrowed it down there from other details. I have a 1981 716 (710 frame), but that year was the first year they went to Shimano dropouts. Pre-1981 710 frames had Campagnolo dropouts (1010). Geometry for 710 frames was identical over these three years, too. So that doesn't help. What is your seat tube length? It looks like a 22.5"/56cm--though Trek took their inch and metric measurements from different points on this size it seems. Still, it looks a little short for a 57.5cm frame, IMO. That could rule out the custom size part.

If we get into the nitty gritty of individual components, more pictures will be appreciated, but from the ones you have taken (thank you!), the headset is Shimano 600, which was spec'd through 1979. 1980 had a Tange Levin. Your crankset matches that of a 1980--it being an SR Forged SAX-5RG instead of a Suntour Vx (windows in the spider arms).

I suppose Trek could have mixed and matched components, especially if you have "late-1979" and "1980" as your bracketing years. You may have a hybrid of both, as makers were wont to do during that time, or, many times. It could very well be a 1979 model. Or a 1980. But since it's a Trek 710 frameset, you win no matter what! Mine is sublime in ride quality, though I am in love with that metallic light blue of yours!

Thanks, I measured the seat tube to 22.5" but the top tube is 55 cm (c-to-c) where it should be 56cm. I'll measure again. I couldn't find photos to confirm the differences in the crankset. I'm not sure if the headset is original, but I'm thinking it is. I agree in that everything seems to point to late '79 to '80. I does ride really smooth. I have a '80 410 (022 Ishiwata), '81 610 (531 Mains, hiten stays), '84 (Mangalloy) and 710 seems a bit lighter ad a bit smoother and stiffer, yet still as compliant on bumps if not better. Yes it is a win, but was hoping this would be my definitive "birthyear bike."

I don't see any references to the "H" serial numbers having a non-standard digit for the year. I did read somewhere on BF that frame builders could build themselves a custom frame...I'm wondering if this is one of them.

Also, just noticed this dent on the top tube under the brake cable. I should be able to roll it and fill it, but the rest of the paint is in decent condition so I'll have to make a decision on that later...otherwise everything else is straight and aligned.
https://cimg3.ibsrv.net/gimg/bikefor...7aea62daac.jpg

Oh and the color is amazing. Imron paint (thought toxic to apply) is really nice, and I think it's called Ice Blue Metallic

I didn't see that fork crown used after about 1981, if that helps.

Hmmm...that's the Trek Investment Cast right? Bummer about the post '81...LOL...that just widened the range. I just noticed the seatpost binder bolt looks different from other confirmed '79 photos I've seen. Going to do a full overhaul and tear down this weekend. The headset is on really tight and I can see marks on it from someone using a standard wrench and not the special shimano 600 tool. I ordered a set and should be here Saturday.

hey, cool huh? You should report this one to vintage trek, it sounds like it may have been built offsite similar to reported 510s. Check the exceptions section of the SN area.

B. Serial numbers for four model 510 frames (with a leading F) have been reported that have similar unexpected year dates. (Our thanks to Rich Ferguson, Fred Gomez, and Chris Tank.) The fourth characters are 2, 3, 4, and 5, there may be more. The frames have the early TREK graphics on the seattube. These frames may be related to the M and N leading serial number bikes in the section above.

Thanks, great timing...I just finished typing up a note and linking this thread in an email to skip. Haven't heard of 710 frame (with leading H) built offsite yet.

No, with those Campagnolo dropouts, it's going to be a Waterloo-built frame.

No, 1981 is about the latest that crown was used. 1979 isn't out of the question.

Ahh, sorry, misread. Thanks! So it's a pre-'81 Waterloo frame with a '3' in the year digit. The mystery thickens :-) Hoping to hear back from Vintage Trek Website if there are any other examples.

Maybe "**** Year Exceptions" note C (or some variant) applies:

Given that the top tube dent is minor and under the cable, and that the paint is in excellent condition, I'd leave it as is. My '85 Schwinn Peloton has a gorgeous fire red-orange metallic paint color and a similar dent. Everything else is fine/normal, and the paint is very glossy. Since it doesn't affect anything, I leave it. History!

"Provenance".

Just finished a full tear down to bare frame. It's a little dirty and greasy, but not too bad. So good news first:

• Not too much rust (considering it came from Oregon)
• Nothing was stuck and all came off without too much effort
• Steerer tube was stamed Reynolds 531
• No other dents
• Got some better pics of the serial number

Bad News (from least to worst):

1. Few more scratches, paint bubbles and spidering (not too bad)
2. Slight bend in left seat stay (minor, I've straightend worse bends)
3. Crack in paint and possibily brazing around left seat stay/brake bridge (doesn't go all the way around)
4. Incorrect bolt used for seat tube clamp...different threading, so stripped original threads

Pictures below...

Bend on stay:
https://cimg8.ibsrv.net/gimg/bikefor...a39b398b4a.jpg

Crack doesn't go all the way around:
https://cimg9.ibsrv.net/gimg/bikefor...18d784ded4.jpg

You can see the metal filings from the threads:
https://cimg0.ibsrv.net/gimg/bikefor...efe65da9d4.jpg

The bolt that was in there to left compared to a proper bolt from another bike upper right.
https://cimg1.ibsrv.net/gimg/bikefor...3dd8fd8752.jpg

Ah, yes. Indeed!

Ok...Good News:

Was able to chase threads on seatpost binder with an M6 thread restorer.
https://cimg1.ibsrv.net/gimg/bikefor...887c29cc33.jpg https://cimg0.ibsrv.net/gimg/bikefor...242d96fbb7.jpg

Also, was able to straighten out bend on seat stay...it's not laser straight, but looks much better than before. Also checked dropout alignment.
https://cimg3.ibsrv.net/gimg/bikefor...00cfd59258.jpg

Looked closer at the crack on the left brazing of the seat stay bridge...it may just be paint, I tried probing with a needle it doesn't really push in. Will have to remove the paint in the area to further inspect. Hmmm.

Upon further inspection the brake bridge is definitely separating. Any one have recommendations on frame builder in the Los Angeles/Orange County area?

Weird how these things seem to happen in waves - https://www.bikeforums.net/classic-v...rek-620-a.html .

Yeah, saw that post. Thinking about doing the same, but also noticed a tiny crank in paint on the stay itself...will have to remove the paint a bit to see if the stay is cracked too. :-(

Found a shop that specializes in vintage bikes near me to get the crack looked at. Taking it there this week.

Honestly, that brake bridge is just poorly brazed as it looks like they missed it with filler.

yes, how did you know?