Modify Trek 720, or new Long Haul Trucker?



cloudhead

New Member
Jul 8, 2010
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Hi,

I've been caught up in the hopes of restoring my 1985 Trek 720, but to do so, I want to have it modified to fit a modern 700c wheelset--27" has just become too hard to find locally. But this also will require modifying the bosses for the cantilevers as well.

I have learned that all the work and restoration of the frame will make it about the same price as a Surly Long Haul Trucker frame, which seems to be the current touring frame of choice for this budget.

I do really love my 720, it's beautiful, elegant, resilient, and has gotten me in and out of a lot of trouble. Also very sentimental--purchased shortly after my mothers death when I was a teenager to get away, and that plays a big part in my love of this bike.

Would the Surly offer me anything above a modified 720 frame? I don't plan on touring the middle of nowhere--just California coastal roads, so I don't need anything "ultimate". However I want to be able to access parts at local shops should I need to.

Thanks,

Court
 

cycleheimer

Member
Mar 10, 2010
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cloudhead said:
Hi,

I've been caught up in the hopes of restoring my 1985 Trek 720, but to do so, I want to have it modified to fit a modern 700c wheelset--27" has just become too hard to find locally.

You might not be able to get 27" tires locally, but you can get great deals on them online. You can get them for well under $10 a piece at Niagara Cycle Works (under $5 sometimes), and usually close to $10 at Nashbar and Performance. I've stocked up on some good deals, and will be able to keep my 27" rims covered for quite awhile. Keep the 720...stock up today!
 

alfeng

Well-Known Member
Jul 23, 2005
6,723
254
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cloudhead said:
I've been caught up in the hopes of restoring my 1985 Trek 720, but to do so, I want to have it modified to fit a modern 700c wheelset--27" has just become too hard to find locally. But this also will require modifying the bosses for the cantilevers as well.

I have learned that all the work and restoration of the frame will make it about the same price as a Surly Long Haul Trucker frame, which seems to be the current touring frame of choice for this budget.

I do really love my 720, it's beautiful, elegant, resilient, and has gotten me in and out of a lot of trouble. Also very sentimental--purchased shortly after my mothers death when I was a teenager to get away, and that plays a big part in my love of this bike.

Would the Surly offer me anything above a modified 720 frame? I don't plan on touring the middle of nowhere--just California coastal roads, so I don't need anything "ultimate". However I want to be able to access parts at local shops should I need to.
I'm not sure why you think you would need to modify the bosses on your Trek 720 frame ...

The difference in radius of the brake surface of a 700c wheel and a 27" wheel should only be 4mm ...

On the typical (as in, older) cantilever caliper, the pad is on a rod which is in what I will refer to as a "gimbal" (akin to the old MAFAC design) ... so, if the gimbal can't slide down enough, it can be canted the additional amount to allow the pads to contact only the rim's braking surface (vs. the tire's sidewall!) ...

OR (particularly, if your cantilevers are the type which use pads that have threaded mounting rods), you may be able to elongate the slot enough to allow you to use 700c wheels ... or, just buy the OTHER type of cantilever calipers mentioned in the preceding paragraph!

Respacing the rear triangle to 130mm from 126mm can be a DIY project ... just do NOT use any additional force other than what you can impart with your own upper body strength ...
Remove the rear wheel ... with a dropout in each hand, exert whatever you perceive to be 30 lbs. of force. Measure & repeat until you have spread the dropouts to 130mm.

Realign the rear dropouts using scrap plywood (to protect the dropouts ... three-or-four layers of plastic cut from a laundry detergent jug & taped together may be thick enough for each side of the dropout) & a "regular" (~12" handle) pipe wrench. Tweak [steel is softer than you may think] with whatever you perceive to be 5 lbs. of force. Measure & repeat as necessary. You want the dropouts to be parallel to the bike's central plane.

There is NO ADVANTAGE in rushing the process ... it won't take very long regardless of the number of repetitions you need to make.
If you already have a pipe wrench (a very LARGE adjustable wrench can be used, but will be less efficient) & some scraps of wood lying around, then your cost will be ZERO vs. the cost of a Surly frameset.

BTW. Most Surly LHT seem to have 26" wheels, and only the larger LHT frames seem to use 700c wheels.
 

cloudhead

New Member
Jul 8, 2010
127
2
0
Thanks for the input. I actually have decided to just go ahead and do the mods. I did find great 27" tires online, but my worries are if im on the road. I'm taking the bicycle shop closest to my house as a worst-case example of what's available if I'm out on the road, and their selection is very slim for older bikes.

The current cantilevers work and have a vertical adjustment, but I have to set it to the extreme and it's still not exactly where Id like the shoes to be. Since I would like a new set of wheels--the current wheelset has an old helicomatic hub that has been giving me some grief lately--as well as the spoke nipples being quite corroded (something I've been dealing with a lot due to a helicomatic and old spokes), I figure it's just time.

The estimate of re-brazing the cantilever bosses was very sensible. I even found a great mom-n-pop frame shop within a decent drive. I'll be keeping the same cantilevers so I can even attach the 27" wheels if i want (in theory)

I also have a bad habit of doing things wrong in the DIY realm, and read up on re-spacing, and this frame shop will take care of it for $30, which is quite decent just for the sake of being ensured it is being done right. They'll have the proper measurement and alignment tools. I'll end up riding in circles if I do it myself.

In the end, I've decided to keep this frame but modify it so I can get another 25 years of hassle-free riding, as it was originally, at least until sizing standards get changed once again. But by then, we'll be riding frames made of nano-structured protein chains so I might upgrade ;-)

I do appreciate all the excellent input. I wasn't sure if it was just me thinking the cantilevers reached...

-Court
 

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