I found this question in yesterday’s search terms: “Can having too small of a road bike make you slow”?
The answer is short and sweet. Absolutely – though I’d have phrased the question a little differently. It is my experience that there’s nothing worse for speed than a bike that’s too small, other than a bike that’s too big. Now, the ergonomics get a little tricky, but there are a ton of factors that can slow a rider down – especially when picking up a used bike. I’ve written a lot about my Trek 5200, a bike that I picked up used, but from my local bike shop. The trick is, it matched me perfectly with one exception – I had to put a different stem on it because the cockpit was too stretched out (the distance from the seat post/seat end to the bar top). These minor complications are quite normal and quite easily corrected (they switched the Trek stem with the stem from my old Cannondale) provided you know that there’s an issue in the first place. Now I’m a pretty smart fella but I’d never have known, just buying a used bike, that the stem on it was the right length, or that I had the proper crank arms, or that the top tube was long enough. That knowledge came with a proper fitting.
Also, with newer bikes, they’ve got a sloped top tube so that allows for a bigger person to fit on a bit smaller frame. It is my understanding that the top tubes are sloped so that the factories don’t have to build so many frame sizes. So that would have to be taken into account as well – and most of us just aren’t savvy enough to take all of the factors into account.
For instance, crank arm length is huge – I have 172.5 mm crank arms (optimal is suggested as 172.95 mm). If I remember correctly, my old Cannondale had 170 mm arms which meant I lost potential torque with the shorter arms… In addition, my old Cannondale frame, even though it was advertised as a 56 cm frame, ended up being an actual 54 cm because of the way Cannondale measured the seat tube – it’s a bit technical, but the top tube was lower than it should have been for a true 56 cm frame… Add to that the fact that the top tube was about 5 cm too short and you were trying to fit a 6′ man on a bike made for someone around 5’8″ or 5’9″. My wife fits quite well on the bike (she’s 5’10”), and the longer reach stem from the Trek made that possible – it extended the cockpit.
I won’t lie though, there was one thing that I really dug about the Cannondale… The bike was so small that I had the seat post hiked up about 6 inches above the frame and about 4″ higher than the handle bars for that classic racer look. Of course, it hurt to ride in the drops for more than a half mile, but I’m sure I looked really cool for that half mile.
As for seat tubes and saddle height, I’ve got a great example that hit close to home: My best friend has got a nice Gary Fisher hybrid that he could only manage 10-11 mph on. After signing up for the Tour des Lacs about 10 blocks from his house I called him up and he was wondering over the phone if his seat post was too short (the last time we rode together – last November, I didn’t know a whole lot about sizing) so I went over to check it out. He had his OE stem maxed out and he was still probably a good inch or two short. He got a new seat post for it just recently and his next ride was a little better than 15 mph. – that’s a 50% improvement because he raised his saddle. The height adjustment got his legs extended properly so he could get more torque to the pedals*.
Fit is everything when it comes to riding fast, comfortably – and it doesn’t matter the type of bike. Size matters for everything from a leisure cruiser to a road bike or time trial bike.
*Now, if I could just get him to work on his cadence a little bit… He’s a gear masher. He pedals slower in a harder gear so he’s working too hard. This is a classic problem with runners – and English Pete is a big time runner.