Size Up or Size Down?
 

I've been going on test rides over the weekend and a little bit this week as well.

I have been massively impressed by the bikes I've test ridden. I've really enjoyed just about every specialized bike I've test ridden. If I buy locally, I have a good shop in mind. I seem to get along pretty well with the employees, and they have a good selection of bikes at some pretty competitive prices.

One issue I'm encountering is that I can't decide between 52 and 54 cm bikes. I've test ridden a secteur in both the 52 and 54 cm sizes.

52 cm pros:

The 52 seems to have a little bit of a 'pocket rocket' feel. It's a bit lower to the ground and feels slightly more secure and quicker to turn.

52 cm cons:

The tt may be just a touch too short, and I'm a little leery of going with a longer stem. Ideally, I'd rather have more reach via the top tube.



54 pros:

The top tube and stem length feels spot on.

54 cons:

The bike feels noticeably higher off the ground and seems more ponderous and less secure while cornering.

I feel like I can negotiate a turn tighter and faster with the smaller bike, while the larger bike seems to lean rather than turn, if that makes sense.

Theoretically, the 54 should fit me better. The top tube, stem and reach seem correct. But for whatever reason, the 52 seems more manueverable and faster.

One shop told me that a shorter top tube plus longer stem is a little less secure on gnarly descents. It's something to consider. Perhaps I just need to go on longer test rides.

What are your thoughts on sizing?

I hope you realize you are the exact same distance from the ground on both bikes? The height of the TT has no effect on CG with your carcass planted high above. Parking lot test rides over emphasize tight cornering, while in reality you spend the vast majority of your time powering straight ahead and carving broad arcs at speed.

When I got my first road bike that was properly fit, it felt totally huge and sluggish. It was 2.5" longer in the TT than what "felt" right before getting a professional fitting. It took a few months to fully realize it was indeed better in every measure, and better at carving turns.

I say fit is king, but if both fit, and you can achieve your target riding position without a custom stem, either is fine. "Quick" handling becomes "twitchy and tiresome" after a few miles though.

Great info. I think I will continue to test ride bikes for a couple more weekends.

I was actually very close to making an impulse purchase after my very first test ride! That was a 52 and the ride was exhilarating. I think I would be very happy with that bike. Then again, the 54's were terrific as well.

I'll give this project a couple of more weekends but I felt really good with the 52 cm secteur.

There could be a minor difference between the 52 and 54...

The 54 is likely to have a slightly longer head tube than the 52, so you will sit a little more upright assuming the same saddle position and crank length.

You can adjust the handlebar height to be the same as a 52 by removing a spacer or two, or by switching stems on the 54... This could give you the same riding position with your preferred top tube length.

The difference you are feeling could theoretically be partly based on the shorter top tube as well.

You, a Roadie? want to stay bent over low all the time until you raise your hands at the Finish line in cerimonial Victory on the day.
the go for the smaller one , you can always have a longer stem swapped in..

Not a go-fast racer type? want to sit up more and see the world around you? go for the larger..

Excellent info, thanks.


Excellent and concise. Thank you.

Secteur geometry link

The 52cm frame comes with a 90mm stem vs the 54's 100. While the 52cm TT is 11mm shorter, the reach is only 2mm shorter because of the different ST angle. Biggest change is a 17mm difference in stack, but unless you're riding the 52 with the stem already slammed then the 54 can likely be adjusted down similar to where the 52 is. That's going to come back to fietsbob's point.

What sort of rides are you interested in doing? Long tours or quick fast rides? Have you looked at the numbers generated by the competitive cyclist fit calculator? Are both bikes at the same shop?

Great point about the reach.

I'm returning to the sport. I would like to start out with 1 hour rides or so a few times a week, primarily on flats and rolling terrain. Some climbing, but not a lot.

It all depends on how you like to ride.

You'll be able to get more aero on the 52 as it has a larger seat tube angle and a shorter head tube, so you'll be able to rotate more forward and get your shoulders lower. But that will shift your weight forward, more onto your hands - in general.

You won't be able to get as aero on the 54 with its taller head tube, but the more relaxed seat tube angle will rotate you slightly rearward, putting more weight on the saddle. You'll probably be more comfortable riding the 54 for long rides, but that depends on you.

And all of those changes are in general - you can shift your saddle forward and back, and set your bar height and stem length.

The only hard and fast differences are the taller head tube on the 54 will limit how low and aero you'll be able to get, and the steeper seat tube on the 52 will cause a minor shift in weight balance, with a bit more weight on the front wheel for the 52 frame.

I'd go with the 52 in your situation because I could get more aero were I so inclined and the slight difference in weight balance wouldn't bother me. But that's me.

It's all about personal preference and feel. No one can tell you what you like.

Myself, for instance, I like a smaller bike- I'm 5'10" and ride a 54cm. I agree that the smaller fit feels more crotch-rockety. It also allows me to get into a more aggressive position; and it prevents me from being stretched-out; and I absolutely HATE being stretched out! A former bike of mine, even though it was also a 54, had a longer top tube, and made me feel really stretched when riding the hoods- it was very uncomfortable.

Go with what feels best to you. Sounds like the 52cm is the ticket. If need be, you can always make a smaller bike larger, by getting a longer stem; raising the bars, etc. -but there's not much you can do to make a larger bike small. Viva le small bikes! :)