What rims are you running on that 720? I ask as rim width drives the ultimate width of a given tire. "True to size" on a 23mm external rim (Super Champion, modern DT Swiss et al) will mean ~1.5-2.0mm smaller on a Mavic MA20/MA40/Open Pro etc (20mm external +/-). And of course, one company's 35mm tire is not the same size as another's 35mm tire. I have built up a pretty decent chart of tire widths when on various rim widths, and upon measuring the width between the bead of a tire (pressing the tire flat, like when they come in their box), can get a pretty darn accurate idea of what the inflated width will be.
As a Seattle rider, I get to be exposed to tons of crap on the roads in addition to the imperfect road conditions themselves. Thankfully my flat rate has been very, very low with larger tires using normal and latex tubes. The two that I run are Soma's Supple Vitesse EX and Compass Bon Jon Pass (standard casing). The Somas I've had in various sizes, but love the 42s for their comfort and speed over broken up roads. They measure nearly 40mm wide on 23mm external rims (DT Swiss R460 in this case) or 38mm wide on a 'standard' rim (MA2, on my 1982 Trek 720 for a bit). Pressures at 34/39 or 40/44 PSI front/rear work really well. I have the Somas on the DT rims with Vittoria 30/38 latex tubes. Works really well and I don't get flats. They also mount "true" to a given rim
I'm running the Compass BJP's (bought
very well used) on my 720 right now, using a normal tube on MA2 rims. 50-52/56 PSI front/rear. They measure 34mm wide on the MA2s at those pressures. The bigger Somas at lower pressures were a cloud, but out of the saddle was a tad mushy, as to be expected. The Compass tires are almost as cloud-like, but have better response, also as to be expected. No flats in these well used tires--just had an old tube go down IIRC.
You can't lose with either tire. The Somas are cheaper that the Compass/Rene Herse, though they do have some hum as you increase speed thanks to their tread profile. The BJPs roll pretty quietly, which is perfect for the demeanor of my 720 (the 7400 freehub is essentially silent when pedaling or coasting).
My 720 is my Accidental Grail Bike and I love riding it. Beautiful craftmanship, lightweight frame, beautiful ride and handling, and fast on the flats with great climbing manners. And as such a bike, it is worthy of spending good money on (at least for me), and that includes tires. I've put quality components (proven on other bikes, combined onto this one) on my 720, including re-spoking the wheels (DT Revolution mostly, Competition on the drive side rear) and replacing a cracking rear rim, and plan to keep it going for as long as I can.
720 on Soma 42s:
720 on the Bon
Jovi Pass 35s:
