Cross Fork for winter bike

[Lead Pantani]

Im planning re-build my old road bike, a Trek 1500 from 2003, to a winter bike by putting on 35mm cross tires, so I can go on some sand roads.
This means that I have to put on a new fork I assume, in order to fit the wider tires. Anyone knows what measurements I need to look for before ordering the fork to get one that fits? I have seen different sizes 1 or 1 1/8, not sure what fits my bike?

Any recommendations on a fork? I was thinking of a low end carbon fork, but they seem to be pretty expensive.

Furthermore, Im not sure if I need to change the brakes as well, I have Shimano Ultegra currently, and it looks like I might be able to fit the wider tyre. Any thoughts or tips?

Thanks!

 

[RDV4ROUBAIX]

Your fork is probably a 1", and you're not going to fit more than 28's in that frame. Even if you did find a fork with a wider crown for that rig, the rear triangle of the frame will still limit your tire size, and you can't change your brakes to fit 35's either. Only way you're going to achieve that tire size if you buy a cheap cross frame with big clearance and canti's, like a Surly Cross Check. fff (fatties fit fine)

When you say "sand", do you actually mean gravel roads? If that's the case, I ride my road bike on the Vitamin G all the time with slick 25's, no problems at all. Don't have to go bigger than 28's if you have deft bike handling skills and the gravel or "sand" isn't too deep.

Great gravel or dirt road tires:

Conti GP 4-Season 25's and 28's
Conti GP 4000 25's (what I use)
Michelin Krylion 25's
Panaracer T-Serv 28's
Vittoria Randonneur 28's

Most of these will fit in the tight geometry of a dedicated RR bike, except for the last two. But I was able to squeeze in a set of 28's of the old Conti Top Touring (now called Top Contact) in my Colnago. The T-Serv's are really nice, almost too tall, though I did race them this spring on my Masi and they were fine. The Vittorias are a comfy ride but a bit heavy due to a wire bead, the rest are folding bead of course.

 

[TheDude]

A 2003 should have 700c wheels. I would suggest a set of Continental GP 4-Season or Gatorskin 28s, which should just fit. Grab some KoolStop salmon colored (wet weather) pads as well. you might find a fender that you can fit too if you don't like spray up into your face. RDV4 gave a good discussion of the issues related to going fat tyre.