Classtime 

I found this:
Javascript Bicycle Chain Length Calculator
Which gave me 58 inches 58 links. I think that is the standard 116 links or 1/2 inch for each of 116 links?

Salamandrine 

I know right? May as well have said his dog ate it. I guess the story is theoretically possible, but sounds like BS to me.

Salamandrine 

Yeah, it means 116 links. It's an older way of saying it. Looks like you squeak by with one chain.

Classtime 

I think I like it.
The 27 x 1 1/4 is on hold for now while I work out the Helicomatic issue. In the meantime, it's 700c Araya 20A with 28mm GP 4000s.
A brand new PC870 chain was perfect.
During a ride of 33 mi and 2500 ft, I think I got the rear shift lever tight enough and as predicted, the saddle is inappropriate for anything but a trip to the store, but it glides along nicely in that "planing" sort of way. It may have been the placebo effect that made my efforts to avoid road hazards more laborious -- I can't be sure after only one ride on this Cadillac. During the ride today, I was trying to decide which of my road bikes should go on CL. That is a sign that this bike (or one like it) will be getting significant attention. I'm still trying to wrap my head around half-step gearing: cross chaining by design? For now, the original cables, housing, hoods, and bar tape are doing their job. Koolstop makes pads for these brakes which is pretty Koolstop. Mine are pretty soft but I may get a backup pair.

Classtime 

I finished building some wheels for it last night: NOS 36 hole Dura Ace, DT Comps, brass nipples, and H Plus Son TB-14s. The 5 speed SunRace freewheel provides some more or less 1/2 steps and I'm getting a kick out of this 1/2 step plus granny thing. The PC870 chain and the long chainstays with the Sunrace freewheel feels and sounds pretty smooth in every gear combination. Here it is on my routine loop. I finally shortened the original brake cables, put on the rack and my C-17. I'm in between TREK frame sizes and wonder if the 22 1/2 would be better. Maybe experienced tourers could comment on my set up. That is my standard saddle height and the bars are a bit higher than my go fast bikes.


Someday, it will get fresh cables and housings.

The Golden Boy 

I like the way you have it set up. (except the saddle sorta looks kinda nose-y uppy to me)

I, personally, like having a little more upright setup- but then again- that's my back and neck.

I'm a little surprised you didn't like the San Marco saddle- I'm also interested in what your opinion is on the Sachs/Huret shifters.

I opted for a 6 speed, and more or less use normal big jumps between gears and then use the front to weasel in the half-step where appropriate. Rather than the constant 'shift, step up, step down, shift' routine.

It really is a really nice riding bike, isn't it?

Classtime 

I know it doesn't look nice for pictures but this Brooks C17 and my Team Pro need to point up like that to keep me from sliding forward. How that can be comfortable for my nether regions is a mystery. My Turbos and Concors are much more level.

I think the original San Marco saddle is a little wide for me? After 25-30 miles, it was infringing on an otherwise enjoyable ride. The shifters do a fine job--the finish is rough and the rear shifter needs to move through a large arc for each shift but at this time, they belong on the bike. The Sunrace 13-16-20-24-28 is not as nice on paper as the original Helicomatic 14-17-20-24-28. I've got a Shimano 14-17-20-24-28-32 with a worn out 14 that might be nice for the local mountains if I can replace the 14.

I'm looking forward to riding it loaded down.

bear_a_bug 

Can anyone chime in on Trek's thinking behind the fender mount near the bottom bracket? It's a mile away from where a reasonable fender line would want the mount. I get that you can use spacers on a long bolt to get it right, but it just seems like absentminded design on a high end touring bike to not provide a better way to do it.

What would have been the standard procedure for fender mounting on this frame BITD?

twolve

Can I ask ‘620 owners (‘85 in particular) what front and rear racks have you found to work well for these? Planning ahead...

Lascauxcaveman 

I'm thinking spacers and a long bolt. But you're right, they could have moved that little cross piece back a bit. Theoretically that would make the rear triangle at least a little stiffer, too, which is one of the things people talk about when they talk about this bike.

Chr0m0ly 

They couldn’t. The ‘85 treks had the chainstay bridge molded into the BB lug. It looks like the same lug was used for all the bikes, and if it was designed to clear a tire with 41.5cm chainstays it’s going to be a little funky looking on a 47cm chainstay bike.




[img]blob:https://www.bikeforums.net/dc1b0642-6f49-4555-aca1-501aabaa537d[/img]

Classtime 

Good question. I want lowriders and a handlebar bag but I haven't seen a vintage Blackburn with a tombstone. For versatility, I'm leaning towards a Tubus Tara and a Rawland Rando Rack.

recovering

Nice tag line!

The Golden Boy 

As Chr0m0ly mentioned, the chainstay bridge is a part of the lug on this bike, whereas most all other bikes have the chainstay bridge as an individual piece. And that sort of goes to the reason why this is a 600 series bike and not a 700 series bike. The rear end (and fork) of this bike was brazed in Japan, then sent to Waterloo for final assembly. I'd guess that's 2 more mitering/brazing jobs that don't need to be done and a place where the tolerances could not be off- or else the chainstays wouldn't fit into the holes in the lugs. FWIW- the only bikes that I've seen pictures of with visually awful brazing were a couple of early 80s Treks with the chainstay bridge done crooked.

Also FWIW- you have to weasel in a short screw between the BB and bridge (mine isn't threaded), thread on a long spacer and then secure the fender to the spacer. I haven't had fenders on my 620 in years, but it was enough of a pain that I just left the screw and spacer in place for when I get around to it again.

jlaw

This guy (Fuji Otaku: The Phoenix Project - Nitto M12 Front Rack) managed to fit a Nitto M12 front rack onto his '85 620 - but it was quite a bit of finagling to get the tang threaded through the fork crown and then get the the cantilever brake rack mounts to work with the brake posts - I think he used post extenders of some sort.



Or, the original vintage Jim Blackburn front and rear racks should work. The rear racks are available intermittently on ebay or elsewhere. The front rack (there are 2 different crown mount styles I think) are rarer. This guy (https://www.crazyguyonabike.com/doc/?doc_id=15640) found both for his 720.



Or, I emailed Velo Orange about their canti-mount front for one of my 620s. They said that with such narrow post spacing (my 620s both measure approx. 60mm c to c) it may require some bending to make the rack stays line-up the canti posts. If I go the VO route I may get their new 'flat mount' rack because it has stay/rack connection points that rotate - might be able to reach the mid-fork mounts on the 620 with this one - need to take measurements and verify with VO before purchase. P clamps are another option.



Or, you may have the easiest time using a front rack that mount to the hole in the fork crown and then has the long vertical legs that reach down to connect to the eyelets near the axle. Like this one from VO:




Whatever you do you may need to drill the threads out of the fork crown to make the rack connection work.

The Golden Boy 

I was looking for some 1985 Trek 620 info and found this thread- it was a great read and thought I'd bump it to see what happened.

Did you end up keeping this one, finding another one, finding another old tourer or just deciding this sort of "touring bike" thing isn't your bag. Baby.

Classtime 

It was part of a serious culling of the herd down to 3 race bikes. I should get a t-shirt made with a picture of that 620 and a bunch of others along with a: “I should have kept that one.”.? I think that Trek did a great job choosing the bits and pieces for that bike.

Edit: You got me going back through this thread! Shoulda Coulda Kept It.