RiddleOfSteel

The saddle: I'm in it to spin it!

RiddleOfSteel

Well, as promised, the brakes are up next. Cantis and their fidgety ways, I tell you!

But first, cleaning!


I dug around at Recycled Cycles for a straddle cable yoke pair that matched and looked the part. So, to troll my own desire for Shimano 'purity' on this build (never mind the Tektro brake levers...), I found some sweet black Suntour yokes. They turned out quite nicely, I must say.


This is a Surly canti brake cable stop that anchors itself off of a seat post binder bolt. The M5/M6 bolts normally used on newer collar/clamp systems is not present here. Instead, the binder bolts and their male/female collar system make for an 8mm diameter. This Surly unit is made for that 8mm diameter, which was great! Also great: the entry point for the brake cable housing was a full 20mm further down the cable stop than other similar cable stops.


You can see here how precious the room is for the cable housing to route around the seat tube and into the barrel adjuster. This is no doubt exacerbated by the narrowly-set seat stays (due to the cleaver seat cluster). On 1983 and earlier Treks, not to mention about every other bicycle in existence, their wider-set seat stays would greatly aid in setting up a shorter cable stop (arm) scenario. So as much as I am reluctant to employ Surly pieces (I think I just can't stand their wacky frame sizing/geometry and million-stem-spacers-used aesthetic/"fit"), this was a critical piece that delivered.


This is the awkward introduction phase of the canti brake party here. Get the brake lever cable into the area, say hi to the loosely arranged straddle cable, and convince the brake pads that they'll be friends with both the rim and the fork blades.


The yoke gets to the party and everybody "walks" closer and closer to final positions. It was kind of a fun game, and thankfully the "cam" system Shimano made was intuitive enough to use. Logically fidgety. I can deal with that.

RiddleOfSteel

Everybody is friends now. And the front brake lever feel is very strong and very crisp. Very satisfying. Also satisfying is the ease in which the brake lever cable is able to be mounted, as well as how easy it is to 'hook' the straddle cable to the yoke. I love Tektro CR720s and their nifty straddle cable yoke, but it is very annoying to set up and run cables through. This bent piece of metal is the timeless and elegant C&V solution.


As we know, one of the "disadvantages" (or simply, hurdles) of 'aero' cable rounting + standard canti setups (meant for 'non-aero' levers and cable routing) is the awkward S-curving the cable/housing must take from the handlebars to the headset-mounted cable stop. I've used a fork-mounted cable stop before, and that eliminates the issue. I didn't want to do that here (read: pay for it, if it was even available at all!), and used the tall Technomic stem to my advantage. The brake cable, coming from the brake lever, would be smoothly routed from the front of the bar to the back of the bar, and then allowed a much smoother, less acutely curved path to the cable stop. Getting the cable housing length right was necessary, and I was able to do that.


Picture of the rear set up. After not liking how nearly non-existent the springs were for the rear canti arms, I swapped springs from side to side. No dice. I feared I may have to tweak them, but I decided to swap the springs back. I must have changed their orientation in their 'pockets' (even if I thought I had done so already) and voila! Tons of spring rate! Naturally this makes for a bit of lever effort when pulling them, but with enough fiddling, I was able to have the front and rear brake levers "bite" at the same time when I pull them with both hands simultaneously.


See the swoop!


Ok, so you all get a sneak peak at the overall proportion of this thing, albeit 'under construction.' The seat post and saddle are in their final positions, as are the stem, bars, and brake levers. It's a great proportion, and thus a great look. All that opining over lost proportion with my Paramount is fixed by small geometry/tube 'movements' (well, if a 30mm longer head tube is 'small'....). I have some shift cable swapping around to do thanks to under-BB routing (for both cables) as well as a 30mm longer chain stay (for the the right/rear cable). We are getting close!

RiddleOfSteel

Cable swap on the right/drive side means I get to 'clean up' that side of the handlebar by completing the wrap. Very satisfying.


Trying to decide which is larger, the rear derailleur jockey pulley's or the cassette's 23T cog....


Just looking up from my chair, doing some initial tuning.


Alignment. Mostly. I did pretty well with Trek's through-the-chain-stay cable routing. Attached to the ferrule is a flexible sleeve that helps the cable not kink. I like the clean routing, but Trek, IMO, could have done this better.


I have a chain stay protector on the way from Velocals (620-specific), which will cover the pretty pretty blue paint, but also protect it. I'll see how the gearing works with this chain length, but am seriously considering picking up a Tiagra 10-speed chain or something locally and using all its length in conjunction with my 11-28T cassette. As with any new build, it's a lot of faffing about getting things to play nice, even if one knows what they are doing. Never a dull moment!

RiddleOfSteel

So it's complete. On a rainy and very windy night, the 620 is a rider. I am reminded that a new build is a new relationship. Tons of unknowns, hoping I'll like the bike, hoping that I didn't fail miserably in some aspect. In this case, I'm hoping that the brakes aren't too noisy (even if that is to be expected for the first few rides as the pads and rims bed in, more or less) and are actually strong (not just feeling good on the stand). I'm also hoping that the shifting is a little better than I was able to get it on the stand. I think the bike looks great, and looks "proper" in stance and proportion. What a great blue, even if the camera can't freaking pick it up in my lousy apartment lighting (Photoshop to the rescue!). Day photos outside coming ASAP!!

As built, she is 10.94kg or 24.0 lbs. I am not complaining!


I guess it's a touring bike. All I see is a fast, comfortable bike.


I'm really looking forward to riding this!!

mountaindave 

Silver DA are still some of the sexiest components ever. I just can’t get into this modern fixation with black components...

You have the rare and historically significant 7403 rear hub. The the third and final iteration of 7400 rear hubs were UG and HG compatible and 8s which carried them through the red-headed stepchild 9s era into the modern 10s era.

A lovely build lovingly built!

trailmix

I have enjoyed mine over the years. Don't worry, those cable housings are long gone.

Kobe 

The Surly cable hanger is a nice piece. I used a shorter vintage one and the brake feel suffered a bit because it could not move fully.

I'm hoping this is the One for you, but I am skeptical. It's not even Winter yet and like me, you seem to need some project going.

RiddleOfSteel

Thank you! I've had every version of 7400 rear hub, including the 1 year only 8-speed UG freehub body. I don't mind black components, but it really needs to be the right kind (gloss or matte) for the build/purpose, which can make a build more expensive as the commitment to the aesthetic composition (in addition to the function) needs to be complete and not partial.

RiddleOfSteel

I almost went with the shorter vintage one because it was period correct, but then thought it through for another second, and said, Surly hanger or not, that's a better idea (the longer hanger/stop).

The test ride will happen today as this is a pretty dry day and the sun is out. Hoping it will bake the water off the side roads, or at least get them to barely damp levels (main roads are bone dry, but filled with traffic). I really enjoy building bikes, but refrained from any of that these last two months until this 620 arrived. I build all year round, so apart from rain and cold, seasons don't effect my idea of when X or Y is proper to do with regard to bikes. The 620 will be A One for the time being unless it's a total turkey. If I logic out my long chain stay experience, it says that 47cm should be quite fun.

RiddleOfSteel

Welcome to the 620 era.

RiddleOfSteel

I gave the sun some time to dry things off before the inevitable, predicted "river of rain" that...hasn't arrived yet? Even at midnight? Oh well.

47cm chain stays are real, y'all. The 1985 620 is no joke.

Front end steering and handling is typical touring bike (73° HT angle, ~51mm fork rake/offset, low 50s mm trail), which is to say that it is smooth, predictable, and tractable. High speed or low speed, you know what you're getting. The long stays are noticeable but not a hindrance or detriment. The bike is your friend, immediately so. I love it when that happens.

So what about out of the saddle acceleration and/or climbing? It is also very good. Some bikes will have you feel the twist and flex as you work the pedals, only syncing up with you once your pedal RPM is higher. The 620 has a beautifully organic and 'with you' give/twist, one that works with you up a hill when you are putting some oomph into it. It loves to rock back and forth. Never 'weak' or out of sorts, just smooth, friendly, springy, and fun!

Bumps? They exist, but again, the 3cm extra of chain stay is immediately felt for the better over bumps and annoying road irregularities. This is not some poorly-damped '70s land yacht (for the record, I love '70s land yachts) that has you feeling a flubby, noodly, wobbly frame over things. It's all together, but that extra wheelbase mutes the unwanted 'kick' that those bumps produce in all bikes. Race bikes porpoise over those, my Paramount deals with them, and the 620 makes them nice. It's crazy to feel the difference, and the Paramount is a (very) good bike/frame!

Brakes are strong! Whew, I managed to not flub that one up, hahaha. No squealing either. Double win.

Saddle and cockpit fit are right on the money. The higher brake lever hood height in combination with the slightly closer stem/bar/brake lever setup (am I getting old?) is perfectly positioned. I'm going to really like this for long rides.

The only bummer is a long cage rear derailleur that is confused by a corncob cassette. I think a new chain (aka a chain that will be longer) and re-installation of the 11-28T cassette will make it happy. I think the derailleur wanted a more extreme cassette profile so as to have the inner (larger) cogs be naturally closer to the upper pulley wheel (to aid shifting). Oh well, I guess I'll have to suffer low gearing!

Anyway, the hype/love is real for these bikes. I truly look forward to more rides. I'm pumped this is my bike. Now I just have to square this bike with my forever love (road/race bikes and their resulting aesthetic), and ask, "Do I really need a bike with shorter chain stays?" Because, wow.

Maybe I need a 1985 720 as well. For "research purposes."

Ok, pictures. What are we waiting for?

Lookin' good.


33mm Soma Supple Vitesse EXs keeping the proceedings both comfortable and sporty (big radius tires mellow the out-of-saddle rocking back-and-forth, and this bike likes to play).


Command central.

RiddleOfSteel

Detail shot time. I enjoyed the lighting this afternoon. We had rumbly rain clouds skirt by us (here in Seattle) on their way east, and partly cloudy skies (aka some blue!) followed. Glimmering direct sunlight lighting the dynamic and opaque clouds behind it.

Straight-on shot of the head tube and brakes.


You can see the touch up paint is not quite the same blue--light reveals all. Still, it's very close in most every lighting circumstance, and it's a LOT better than primer or bare steel.


Sweeting Vintage TRAK, bro!


I'm actually happy that the frameset isn't aesthetically perfect, just pretty darn nice. All the components I have are the same, and thus match. Great cohesive look.


Just a 7700 GS rear derailleur 'throwing' it's pulley wheels far forward, as if to imitate rear derailleurs of yore.


That chain goes for some really loooooooong walks between gears, I must say.


I swear I didn't photoshop the sky (or this image, other than resizing it)!


Gotta rep that 531 street cred, even if 501 has greater tube representation...


More rigging. The seat stays on this 620 are quite slender. The socket-style lugs may be...less elegant than other lug types, but the slender, narrowly-set stays are a lovely, delicate design element that deserves mention.


I should get some fenders now.

trailmix

I am a big fan of looooooong chainstays. They just feel right.

RiddleOfSteel

In my accidental quest to "collect them all" (all kinds of chain stay length bikes), my previous longest bike were several Cannondale ST400s. Those felt great, even if they were part of a much stiffer aluminum frame. Still playful. My former '82 Specialized Expedition's stays were the Peak Touring Bike standard of 45cm, which felt great as well. These 47cm units just add to that, giving up nothing. I've ridden race bikes much less playful out of the saddle. It's a good place to be.

trailmix

Never had an Expedition but old Cannondale tourers with their 45 3/4 cm stays are awesome. We must be on the same quest, I have been hoarding old tourers over the last few years. I can't seem to get enough of them.

Classtime 

Looks Great. One of the best Big Bikes I've seen. Nice job. You've likely already experienced the 1/2 Step + Granny set up but those long stays are perfect for it. I only had a six speed FW on mine and it might work the same with 9 or 10: There really wasn't any cross chain racket. However, U-Turns and parallel parking in the garage took planning.

RiddleOfSteel

Thankfully for you, or for other people my height, this 620 is the only complete bike I possess, and I'm more than happy about that. Previous tourers are smaller in size than I'd prefer, with ~65cm being the absolute limit (66-67 ideally, especially for race frames...it wavers) and 64cm being too small to proportionally work out unless I want more saddle-to-brake-lever-hood drop. I can do that, even if I am spoiling myself with things now.

Future ideas include a Fuji Touring Series V (IV is fine, too) in their 64cm size (yeah, a cm too short) and a 1984/5 Trek 720 in 25.5" size (of course). I have...a modern bike in mind, just to see if the spirit of vintage touring bike geometry lives on in a bike spec'd the same thirty years on, but we'll see about that.

RiddleOfSteel

Thank you!

I've ridden half step gearing, albeit briefly, and with a modern cassette. It was alright, and I think there was a reason half step gearing was dropped as soon as 7-speed FW's and cassettes became available (triples went to wider/even spacing). I ran a number of gear-inch calculations with a 3x10 system, which included 53/39/26 triples, a half step triple, and close- and wide-range cassettes. A lot of work, but the half step triple gave considerable overlap/redundancy in gearing, and thus a 53/39/26 + 11-28T was chosen at the time. I plan on going back to that 11-28T soon. Have my gearing cake and eat it too. Super low for uphill, and super tall for flying down (and I do use the 53-11!).

RiddleOfSteel

Well, after an impromptu 24-ish mile night-time ride with @ctak turned into a ~40 mile ride for me (new record post-knee injury) and a 47 miler for him, I am blown away by the 620. Holy cow, people. If you aren't in on this 47cm chain stay stuff and you appreciate an uncannily smooth, stable, yet responsive and fast ride, you need to be!! If you're an in-saddle-only kind of rider that doesn't push the performance envelope, I'm confident the original 27" wheels will do fine as you'll reap the considerable rewards that are those long chain stays. If you want to increase the performance and enjoyment envelope further, get a decent set of 700C wheels and tires. Leave Paselas behind and go for the Somas and you'll get the great ride and handling without the Rene Herse price or puncture-proneness (depending on who you talk to or your personal experience). MA2 rims came laced to anything from Dura-Ace to RX100. It's all good.

I found myself laughing at just how well the 620 handled some really crappy stretches of industrial Seattle roads. Stuff that my '74 Paramount would have bucked me off on were absorbed and contained superbly. On smooth roads, the bike just flies. Sprinting when 'feeling it?' Great! Out of the saddle mashing to get up a hill or barely make a yellow light when you're dead tired? It's got you covered! That last scenario is particularly significant as no bike has cooperated with a tired leg mash session like the 620 has. Usually, the effort is met with a 'flatness' (and thus futility) in any other bike, pretty much. The dang thing is magic.

The only bike that could have given me any preview as to just how good The Long Chain Stay Life could be was my '83 Expedition with its 45cm chain stays. That remains a fantastic bike, even if it didn't fit me anywhere near as well as the 620. Speaking of fit, the slightly higher and nearer stem/headset position was perfect during the ride, both when fresh and when fatigued. So wonderful!

We hit some really rough pavement that necessitated "riding light" or just lifting out of the saddle. Due to a combination of a very polished seat post, well greased seat post and seat tube; the seat post slid down a whopping 1.5", likely toward the end where we encountered the rough stuff. I had the binding bolt sufficiently tight before, but perhaps that wasn't enough. I still need to swap rear cassettes to a 11-28T as I miss the extra flexibility (especially as I build endurance), as well as a longer chain to go with it. But to have a slowly slipping seat post be the only thing "wrong" that went on during a 40 mile ride (the second only of my 620 tenure)? That's fantastic.

Heretical take-aways:

47cm chain stays are for real, and are game-changers. I am pretty much spoiled now as I get to have both incredible speed and comfort in one bike, with no compromise. I'd say the lower limit, set by the Expedition, is 45cm. Anything less is just...I don't want it, especially on city roads. My Paramount, with its 44cm stays, is a great bike! The 620 is next level, period.

Why do I look for other bikes? They aren't the 620 or anything close, apart from maybe a 720. But even then, how much better, if at all, is a 720? [I suppose I will have to do the hard work of finding that out!]

The 620 is my Accidental Grail Bike and I am fully in love with it.

Do I even care about road/race bikes any more, apart from looks and (now, past) desire?

I am beyond happy with just one bike. Crazy? Crazy. But not. Sure, with a brace of Dura-Ace, it makes things nicer, but honestly: RX100 / MA2 wheels + your favorite 'regular' triple crankset, 'regular' FD and RD + saddle, and the aforementioned Soma tires, and you have my bike at a cheaper price point. Which means you have an epic bike for non-epic prices.

mountaindave 

I love it when a plan comes together!

According to the Trek database, only 250 were made in ‘85. I wonder how many are still in existence beyond yours.

Interesting geometry too, the angles were just slightly steeper than the 720. Perhaps that explains some of its “raciness.”

You have a rare gem there.

daka

I can't say that I have thought about this much before but the inclination of the seat tube combined with a large frame size moves the rider back over the rear wheel as they go up, likely reducing ride comfort. It seems entirely appropriate to lengthen chainstays in this situation to put the rider's behind between the wheels again. A proportional frame size change rather than just a stretch in the vertical axis. You may now be enjoying ride comfort that would be "typical" to a rider of more average size on, say, a 56cm frame.

The bike looks great and I'm glad you are enjoying it!

RiddleOfSteel

You ran through the serial numbers, too? I did for all sizes of 1982-1985 720/728s and 1984-1985 620s. 1 of 250 in the 25.5" size for 1985 620s, or, on average, 5 per US state. I would imagine the distribution to be more proportional per state population and demand, but still, that's not very many at all.

I looked at 720 production and there was only one 720 built in calendar year 1985, and it was a 25.5" model. There was a HUGE order push in the late summer of calendar year 1984 to build 720s, presumably for the following model year (as they phased them out?). There was just enough of a time break between the 'normal' 720 numbers and the tight cluster of 105, 170, 300, and 400 unit orders for the (again) presumably 1985 720s. Alas, 25.5" 720s for '1985' total....76 all in. 1.5 per state, average. 127 total for 1984 (2.5 per state).

1985 620 breakdown: 3,351 total
19" - 350
21" - 950
22.5" - 1151
24" - 650
25.5" - 250

1982 728 breakdown: 2,460 total
19" - 300
21" - 549
22.5" - 661
24" - 650
25.5" - 300

1983 720 breakdown: 2,068 total
19" - 150
21" - 452
22.5" - 826
24" - 440
25.5" - 200

1984 720 breakdown: 1,454 total
19" - 152
21" - 350
22.5" - 525
24" - 300
25.5" - 127

1985 720 breakdown: 1,857 total
19" - 170
21" - 405
22.5" - 750
24" - 456
25.5" - 76

RiddleOfSteel

You make a great point. I've been a proponent of small 700C frames bumping down to 650C so that the top tube, seat tube, and head tube angles can all be normal, with proportional 'normal' front end geometry (and thus handling) without the toe-overlap problem. We normally see frames stretched up (seat tube) and forward (top tube) as that is most crucial to fitting an increasingly taller rider, but not much effort has been to increasing the wheelbase rearward for proportional rider balance (like you said, of a 56cm frame/rider). Maybe people tried it and it wasn't that big of a deal/difference. Maybe for race bikes, things just need to be tight for peloton riding. All the properly big C&V bikes, just about, were all mid-level at best, and often just entry-level, with similarly-ranked components.

There's been a KHS Flight 747 and the Zinn and Gunnar stuff, but they all look incredibly awkward and disproportionate. I don't mind a sloping top tube, but it needs to be angled correctly, especially on a super tall/large frame where everything is just magnified. It's why we don't see swoopy lines on container ships or big pickup trucks. That stuff works for small things, and the big stuff needs horizontal lines to span the distance and visually anchor/keep things in check. The last thing any big rider needs is a non-lugged bike that looks like part of the scaffolding on the side of the building collapsed.

RiddleOfSteel

@daka I ended up putting around with a pen, a pad, and a calculator. Oh, and a CAD program that I've input all my bikes into. I developed a few formulas and ratios to create a simplified (but probably pretty accurate) way to measure, based off my 620 as the "standard," the ideal chainstay length for riders on other sizes of bikes. There are, of course, many factors that also affect overall rider balance and ride quality, and I am aware of many (and have written on as much).

I have a set sit bone setback number, and that point, along the wheelbase of the 620, split between the front and rear wheel at a 1:5 ratio. That is to say, that longitudinally, from the sit bone point to the rear axle was 16.5% of the wheelbase, and from the sit bone point to the front axle was 83.5% of the wheelbase.

From there I made a formula to calculate the sit bone setback point of a rider of/on a 56cm frame (as you gave as an example). The "bogey" or example bike I used was a 1986 Schwinn Paramount road/race bike. 410mm chainstays, 73° HT angle and 40mm of fork rake. Good, long-range geo, at least in my experience. Well wouldn't you know? That 1:4 ratio reappeared! [Side bar: geo varies so much per road bike/brand, and a slightly shorter top tube would bring those ratio numbers even closer to that of my 620, but for the sake of simplicity, the 1:4 is fine to claim here] Maybe that was a lucky guess--the 56cm size--maybe not! Whatever it is/was, it ended up being pretty much spot on. So as far as neutral balance/rolling goes, a rider meant for a 56cm frame on a 56cm frame, in theory, feels very similar to me, a rider meant for a 65cm frame on a 65cm frame.

Post edited on 1/11/21 to dig down and find frame size : chain stay length numbers that mimic my 65cm/47cm setup all the way down to a 47cm frame. Correcting ratios, recreating formulas, etc. Maybe this is why I was a designer? Eh, I'm just a bit rusty. Getting it right eventually!
More mental food to chew on, but this was/is pretty fun.