I installed a pair of 35mm tires and the top/surface tread of the front tire nearly touches the brake arms where the arms go above the crown of the tire (not side clearance issue but top clearance issue) -- with just a couple millimeters of clearance. It will ride just fine, but is this safe? Do I risk a piece of road debris getting caught between the tire and the brakes sending me over the bars?

The bike is my dearly beloved 1976 Schwinn Super Le Tour 12.2, which I bought brand new with my paper route money. These days, it has Vuelta wheels with bladed spokes, a modern seatpost and saddle, modern dual pivot brakes and aero levers. I'm switching from all road riding, on 18mm tires, to mostly riding on Harrisburg's 19-mile Greenbelt, which is a mix of blacktop bike path, busted up concrete, gravel and some city streets. Oh, this bike is such a joy. 32mm tires were just fine, but I wanted to experiment with 35s for better control on the gravel.

Is this tight clearance between the tire's top crown tread and the brakes dangerous?

Couple of mm is more than you get with some mudguards (fenders). What debris do you expect to pick up which will get stuck? the chances are if some-things going to get stuck, it wouldn't make any difference if you had 1mm or 10cm of clearance as it would hit the fork blade as well as the crown.

I have a similar issue with my 1976 CCM with 38mm wide tires. I don't find it to be a problem, although when debris gets stuck in the tire it rubs on the fender. Nothing has ever gotten caught between the tire and frame/fork/brakes, though. I think it is safe.

I wouldn't ride it.. put the proper size tire on

2mm with a 35, you have a bike designed for a 28.

another text based blind guess, w/o pictures..

Bene Sugg: shop for a bike, that fits the tire you want to use.

The question is what is the clearance under load? I had a similar issue and ultimately realized that although they seemed to just fit, under actual riding conditions there was some contact and I ultimately went to a smaller tire.

This bike and I have been partners since 1976, so I won't be shopping for another bike. I believe the bike came with 1 1/4 inch tires when new (on 27 inch rims), so really, when I had changed it to 18mm and later to 28mm, I was riding way skinnier of a tire than the factory had anticipated, albeit on new 700c wheels. The best fix maybe would be for me to go back to the original brakes, since the dual pivots have far less head room for a bigger tire than the diacompe factory brakes had.

If the bike came with 27 X 1-1/4 tires then it is designed for 32 mm wide tires, not 28.

If the tire is not rubbing then it is fine. Racing bikes come stock with extremely limited tire clearance and it is not an issue.

I ride bikes with tires that barely clear -- as long as the tires aren't the type to pick up small rocks, you'll be fine.