RiddleOfSteel

Hi, everyone. Ol' Riddle found another frameset--found another vintage TREK frameset--to take home because it was a neat (semi-faded) color, my size (25.5"), and had really pretty detailing. I just deleted a few paragraphs of writing because I realized my prior dropout-to-fork-blade/stay transition identification was based off of 1981+ Trek frames and not pre-1981 frames. Post 1981-ish frames, if possessing a concave or scalloped transition, indicate, in my experience a 700-level frame or better. This is true looking at 400/500/600 frames vs 700 frames (online and that I've owned). I was looking at my former '79 510's photos and realized they had the same transition. So I may be setting myself up for being bummed out as I sold my 510 frameset because, while very nice, was a bit indifferent feeling when out of the saddle. Ishiwata 022 tubing. Chestnut metallic paint.

The bike shop selling this frameset passed on it being an eBay money maker from what I was told, as their vintage guy deemed it not worthy. A repaint with fading, no decals or head badge, and a nearly indecipherable serial number likely didn't help. Perfect for a Trek fan who thought he may be lucking into a nicer frame than others realize.

So now I need your help in determining if I do indeed have a 710, a 910, or if it's another 510.

From what I've been able to glean from playing light and reflection games, the serial number follows the pre-1981 LNLNLNN pattern.

The first character (a letter) gives us the model, and with 43.5-44.0cm chain stays, it's a x10 frame without question. F for 510, H for 710, K for 910. There is a faint vertical line/groove stamped with a paint dip in the middle of it angling to the right, which confirms all of these letters as possibilities as that dip signifies a non-vertical line groove, like the horizontal leg of the letter H. I did not notice a horizontal line across the top (though will look again), which would indicate a F/510 model. The paint thickness is average, and it's not powder coated, so the numbers may just be faintly stamped.

The fourth character is a 2. This may be one of the tell-tale signs of a 510 since vintage-trek shows Year Exception B (numbers not 6, 7, 8, 9, or 0, but rather 2, 3, 4, 5) as a 510 "issue." This and the first character are the most critical. Dropout detailing and Campagnolo dropouts offer no help.

I look at the steer tube now (photo below). Inside of the steerer is splined with 5 shallow, wide splines. Dumb question: Is this an Ishiwata thing, a 531 thing, or something else? I know Columbus is rifle/spiral splined. I don't remember straight splines on 531 ever, but don't remember looking at my 510's inner steerer.

The outside of the steerer is sanded like it would be for a repaint. No markings or stampings at all. Zero help there.

Frameset weighs right at 3200g or just under using some math and conversion. This puts it inline with my previous 510 and my '82 720 framesets.

So that's what I got. I really like the deep lavender metallic color, and think it'd look really nice with all the polished silver and tan wall tires. Don't know about white saddle and bar tape for practicality (I've done it before), but that would really complete the look.

Anyway, onto photos. Thank you for your observations and input!


Fun colors!


Holy Paint Fade, Batman!


Lol, what does that say??? No kickstand marks like my previous 510, so that's a bonus.


The spliiiiiiiinnnnes....


Steerer is rough--unbecoming of Ishiwata and Reynolds at the very least. I think Columbus steerers were also decently finished. The fork is original/matching to the bike and is the correct length.

RiddleOfSteel

Well, I may have answered the model number and thus tubing questions. Took a look again at the faintly-stamped serial number, dancing it in the light again. The second character, a number, will be a 5 for this frame size. The top right section/leg of the 5, like the bill of a ballcap, is present in the stamping. Almost cuneiform in miniscule triangular indentation, it is matched to its left, where the first character should be. That identical horizontally-angled mark should seal the deal, making this another 510 constructed of Ishiwata 022 tubing. If you have observations and thoughts to the contrary, feel free to air them.

It's been two years already since the Chestnut 510, and my riding sensitivities and sensibilities have evolved. I'm game to give it another go. The right fork dropout needs realigning, and the rear spacing is ~122mm (measured with an inch tape measure and converted), not the 126mm it should be. I'll probably order some decals for it before Velocals closes up retail operations, just to have them on hand should I decide on refinishing the frame.

I'll try to get a whole-frame photo or few. Going on three years with a phone camera that can only focus about 5" out from a subject, and the decommissioned other phone (used for photos) is now gone. For now, I'll dream up a build and hope that it will be a more inspired ride than before. It fits 35mm tires up front and sorta-maybe-technically-in-your-dreams in back. Best to go with a 33mm tire there.

JohnDThompson 

That's a 5nn series frame; Ishiwata 022 tubing, brazed in Waterloo WI. May have Campagnolo 1010 or Shimano SF dropouts, depending on availability.

Five straight ribs in the steer tube is characteristic of Ishiwata 022. Reynolds never put ribs in their steer tubes.

RiddleOfSteel

Thank you so much! Ahh, this is why I come here. Invaluable information! I was figuring that the steerer's exterior would tell me something, but seeing it blank was a bummer. Trek would have let the paint blend into the steerer a little, but none of that was present, likely due to it being repainted.

The dropouts are Campagnolo, so it's basically my ~'79 510 with a different paint job. At least now I know what decals to get.

RiddleOfSteel

Update for the annals of Bike Forums and internet history which will totally matter, from catalog sleuthing, this 510 as well as my chestnut brown 510, are 1980 models due to their Campagnolo dropouts, at least as specified in the brochures. Other dropouts were spec'd for the 510 in 1979 and earlier, as well as 1981, leaving 1980 as the only Campagnolo 1010 dropout-equipped year for these Ishiwata frames. Don't know how that escaped me two years ago. Oh well.

In looking at production numbers--this is always interesting to me as the ends or tails of the frame size bell curve are often so sparsely populated--looking at 1981 and extrapolating to 1980, the 510 was produced in smaller numbers than the 710 (less than half of 710 production--800-1000 frames vs about 2000-2500 710 frames, in a 'production year'). @JohnDThompson I don't know if you remember (or were privy to) how many frames were made when you were there, specifically 1980 and earlier. It's alright if that stuff is lost in the ether. I've availed myself of the production numbers on vintage-trek and it is staggering how much things ramped up from 1981 compared to 1982 and beyond. [TL;DR territory now:] I found a Trek blog post stating 904 frames were made that first year in 1976. A linear production progression to 1981's 9000 or so frames would put 1980 numbers at about 7500. If parabolic production increases, 1980 numbers would be about 5200.

Further TL;DR production educated WAG numbers if starting from 904 in '76 and ~9100 in 1981:

Linear increase:
1976 - 904
1977 - ~2550
1978 - ~4200
1979 - ~5850
1980 - ~7500
1981 - 9100ish

Parabolic increase:
1976 - 904
1977 - ~1130
1978 - ~1830
1979 - ~3140
1980 - ~5200
1981 - 9100ish

Pretty much not a lot in comparison to later years. Add in roughly 45 years of time, chance, moth, and rust, and it's no wonder these aren't as prevalent now, especially outside of Wisconsin and the upper Midwest.

Ok, now to do more productive things today...

JohnDThompson 

I don't know specific numbers, but when I started at Trek in 1980, annual production was in the neighborhood of 10,000 frames (all types). By the time I left in 1986, it was well over 150,000 frames/year.

bikemig 

Nice pick up. I'm a big fan of early treks. The Treks I've seen from this era were all set at 123 mm so you could run a 120 OLD or 126 OLD wheel.

​​​​​​​

RiddleOfSteel

I forget what my brown one was, and it may have been spaced to 126mm before I got to it as it took a 130mm axle without fuss. I remember all my '80s Treks being 126mm/easy to put a 130mm axle in except for this purple one. Seat stays are dead straight on their outer edges if you put a straight edge to them--to me that lends further credence to the 123mm setting they did. I'll try and get a metric measurement via calipers instead of 50' SAE tape measure.

HelpSingularity 

Good Gawd, I had no idea they were pumping out those kinds of numbers. I have to admit I never really thought about it but man, that is a lot of brazing going on.