Tires: Go big or go home?

For years I've been reading about the benefits of wide, low-pressure tires on the road (mostly on Jan Heine's blog, Off the Beaten Path, but elsewhere too). Even without much first-hand experience, I have to say I'm all but convinced. If nothing else, common sense seems to go against skinny high-pressure tires in almost every way.

Last winter I re-built a vintage Specialized Sequoia with my own handmade 650b wheels mostly to allow me to run wider tires. Unfortunately, the 42mm Grand Bois Hetre tires that I had acquired for that purpose didn't quite fit--I had to pull the rear wheel all the way back in the dropouts and even then there was too little clearance at the chainstays. That was strike one. More importantly, though, I soon found myself hard up for cash. No need for strike three; that was reason enough to sell the bike after only a handful of rides on it. So I did, and for a while, the dream of voluminous lightweight tires receded.

Recently, however, the Civia aluminum fenders on my Miyata 615 died:

The fenders had been in service for two years, and I'd gotten a killer deal on them (just $40), so no big deal that they kicked the bucket. But with the fenders off, I got to thinking: I now had more clearance for big tires. But how big? Before, I had been running 32-34mm tires (actual width) under the fenders. Any bigger and I'd start to encounter fender-on-tire rub, or else the front tire would rub the nut securing the fender to the fork crown. With those considerations gone for now, I was eager to find out what the limiting factor on tire size would be: the distance between chain stays? between fork blades? the gap between tire and fork crown?

I took measurements as best I could, but it's not always easy to know where the widest part of the tire will end up, or how tall the tire will sit on my rim, or how little clearance is too little. To a certain extent, it was a guessing game, but I figured max tire width on my frame was somewhere between 39 and 43mm.

I should mention that apart from Jan Heine's crusade to popularize wide 650b tires, this blog has also been a big influence on me. It's written by a fellow who seems to spend most of his time bikepacking all over the globe. I have to take it in small doses, or I run the risk of becoming overwhelmed with envy and a sense of my own crushing banality. Anyway, the idea of backroads touring has always interested me and this blog is really inspiring me to pursue it as a long-term goal.

Psyched about the idea of riding on dirt and gravel--99.9% of my riding has always been on pavement--I've begun taking short excursions on trails. A recent bone-jarring ride on washboard trails and a spill in deep gravel, however, have convinced me that, 1) I need to work on my handling skills, and 2) I should probably have more suitable tires.

So now, not only do I want to go as wide as possible on tires, I also want something that will feel sure-footed on trails. After a lot of shopping around and a little hemming and hawing, I ordered some Schwalbe Mondials in a "28x1.75" size, which translates to 700x44.5. I figured that since Schwalbes are known to run a little small, and since my rims aren't all that wide (22.5mm or so), these tires would really come out to 40-42 mm for me. For the record, at $90 each (retail) these tires are far more extravagant than I any that I've bought before, but I found a great deal on them and with the recent sale of the Raleigh Portage II, I felt like had a little spending money to spare.

A week and a half later, my new tires arrived (direct from Germany, no less). An anxious tire fitting session ensued. Since I knew things would be tight, I made sure that my wheels were nice and true and that the tires sat evenly on the rim all the way around. 

And the verdict? Damn, these tires are big. A little too big for my frame, sadly :(

The pictures above show the clearance with the rear wheel pulled all the way back into the dropouts. As you can see, there's only about 1.5-2mm of space between the rear tire and chain stays, maybe even less between the front tire and fork crown. There are at least a few reasons I can think of for not actually riding this setup: 1) If the rear wheel goes out of true there's going to be a whole lotta rubbin' goin' on, 2) If a small rock lodges in the tread of the front tire, there's a good possibility that the wheel will lock up, and 3) It's a pain in the ass to remove or install either wheel since the tire has to be deflated and everything has to be just so.

Okay, so I feel a bit foolish for thinking this might work. On the other hand, I know something about my frame that I didn't know before. And I'm probably also better at gauging tire capacity than before. At least I hope so. On the con side, this experience has me jonesing even more than before for a cool old Stumpjumper or something else that can fit bigger tires. I'm even allowing myself to dream of something like Velo Orange's new off-road-touring model, the Camargue.

P.S. Hit me up if you'd like to buy a set of 43mm Schwalbe Mondials (Evolution Line).