I have been looking a while on ebay for a conversion project. Some listings, not many, state what size wheel is needed, but most do not.

Is there any useful rule of thumb to know what you are getting? Are US frames usually 27 inch and European/Japanese frame 700c? Is there some general rule that before such date they are 27 after 700c?

If you buy a 27 inch wheel bike can you run 700c wheels? Vice versa? Will this effect the break reach?

If you buy a 27 inch wheel bike, is it hard to switch forks to run 700c wheels is the answer above is you can't run 700c on a 27 inch bike?

This is probably a pretty dumb question, but it has gotten the best of me. Thanks for all assistance and bearing with us novices!

There really isn't a problem using 700c wheels on a 27" frame. All you need is a long reach brake caliper. You can buy a Tetkro front brake for less than $20.

Don't let 27" vs 700c effect your decision if you find a frame that you like

It's not really a big issue. 700C wheels have a bead-seat diameter of 622mm, for 27" it's 630mm. 8mm difference in diameter is 4mm radius, so if you put 700C wheels on a frame designed for 27" the brake needs to reach 4mm further -- less than 1/4 inch. Often the existing caliper will have that much adjustability, and if not, long-reach brakes are readily available, as Dave said.

If the bike needs a new fork anyway, you'll probably end up going to 700C. It's not really hard to do.

On the other hand, if you find a good deal on a 27" bike and the wheels are in good shape, there's no need to switch right away. A pretty good selection of 27" tires are still available; not so many as 700C, but plenty.

As for the history, "10-speeds" and "racing bikes" sold in the U.S. used to be mostly 27". The change-over to 700C happened mostly in the early 80's, but it was gradual, so you can't pick a specific date.

I addition to ebay, don't forget to check garage sales and thrift stores. You can get real steals there, and you can inspect the mechandise. My first fixie conversion was a frame I got for $5 at a garage sale. It still rides great.

That takes care of a big worry and thanks for the advice about thrift stores.

I addition to ebay, don't forget to check garage sales and thrift stores. You can get real steals there, and you can inspect the mechandise. My first fixie conversion was a frame I got for $5 at a garage sale. It still rides great.

I agree. There are some other places too but, that's a secret! I keep an eye out on ebay and it's definitely a seller's market. The prices that these bikes are going for and what people are bidding on, are ridiculous! People are paying way too much for this stuff. Once in a while you will find something or get lucky. Keep it simple!

Those 27 inchers are nice on rough back roads. I love taking mine out on the back roads that would give my 700c bikes a hard time. They make nice rec/touring bikes. If you're going to be drag racing go ahead and get a 700c bike.

Those 27 inchers are nice on rough back roads. I love taking mine out on the back roads that would give my 700c bikes a hard time. They make nice rec/touring bikes. If you're going to be drag racing go ahead and get a 700c bike.

Unless you're running significantly fatter tires, I can't imagine anyone could tell the difference in ride quality between 27" and 700c. The difference in diameter is just over 1%. My guess is you have 23mm tires on your 700c bikes, and the 27" has 1 1/4", equivalent to almost 32mm. The bigger tires are what you feel. You could get the same cushy ride on the 700c bike by using big tires (if they'll fit in the frame).

Unless you're running significantly fatter tires, I can't imagine anyone could tell the difference in ride quality between 27" and 700c. The difference in diameter is just over 1%. My guess is you have 23mm tires on your 700c bikes, and the 27" has 1 1/4", equivalent to almost 32mm. The bigger tires are what you feel. You could get the same cushy ride on the 700c bike by using big tires (if they'll fit in the frame).

The difference in ride could be due to geometry, I have 27" and 700C bikes and the 27" ones have longer wheelbases and more relaxed geometry so they do ride much differently even with the same wheels....mine are from the '80's and are similar to what Rivendell sells these days and work great for loaded touring....