Frame Size?

Dewey Thiessen in Dallas is experimenting with different frame sizes and has gone for a smaller frame than he has been using. He wants to know if using the smaller frame will be a problem.

Question:
Although I usually ride a 54cm frame, I found a used 52cm Specialized Roubaix Pro frame in pristine condition. I have a 54cm Cervelo RS that fits me well. I purchased the Roubaix frame and built it up with the same dimensions currently on the RS frame. Using a 130mm stem and with a lot of seat post showing (but still well within the minimum insertion), there isn’t a 2mm difference in any of the seat-to-bottom bracket-to-handlebar measurements.

The RS has Sram Red and the Roubaix has 2010 Sram Force. I like to ride both bikes and both bikes feel amazingly the same. The Roubaix eats road buzz a little better and the RS accelerates a little better but both are excellent rides.

My question is, can setting a smaller frame up like this cause a problem? I think this actually makes the bike smoother and even lighter and I’m wondering if I shouldn’t set all my bikes up like this.

Hi Dewey.

As long as the bike fits, ride it! Make sure the measurements of the seat to bottom bracket, the handle bar to saddle, the saddle behind the bottom bracket and the drop from the saddle to the handle bars are the same, if they are then the bike should feel the same and fit you well.

The problems could be that the handling could be different and it could take you by surprise if the cornering or descending is a bit more “lively”. With the smaller frame you may have more foot overlap with the front wheel making tight corners tricky.

Just look at the dimensions of sloping frames, obviously the compact frame design is much smaller than the old fashioned horizontal top tube style. If you put both the bikes together they may not be the same as the angles of the tubes will be different, but don’t worry about this as long as all the measurements all work out to put you in the driving seat, so to speak. Personally I have been riding smaller frames over the years and must admit the handling and the comfort is better.

If all the measurements are the same then there is no problem. Go for it Dewey.