gideonbikerider

I am 6'-1" tall and am about to buy a road bike on ebay. I have figured my size for either 56cm or 58cm. I may buy a trek 5200 listed at 56cm, but have been told that trek measures their bikes from center of bottom bracket to top of seat post tube. Some other bike companies measure from center of bottom bracket to center of main tube, along the seat tube. Does trek measure center of bottom bracket to center of seat tube? Also, the trek 5200 has a listed standover height of 30.5". Is the trek 5200 at 56cm the correct bike for me?

Thanks for the help.

onkey

I'd probably go for the 58. I'm 5"11 and have a Trek 5200 56.

allez

+1
im 5'10'' and my frame size is a 55-56

BeeTL

I am always surprised when people throw out manufacturer's frame "size" like it means anything at all. Sizing from brand to brand varies widely. The most important measurerment is top tube length, then cockpit length, then saddle to bar drop.

Bike geometry is a little complex, but not rocket science. However, until I had a Serotta fitting every guess people made about frame size for me was dead wrong.

Read this information by Sheldon Brown: https://sheldonbrown.com/frame-sizing.html

Then, go to www.wrenchscience.com and www.competitivecyclist.com and follow the fit process.

If you are young, light, fit, and flexible this may not be too important for you. However, for those of us who are less fit and planning on putting in significant miles, fit is absolutely critical.

By the way, it took me three bikes to figure this all out!

alanbikehouston

Because every bike company uses different sizing systems, you need to test ride a bike and take your own measurements before buying. The only "factory" measurement that is helpful is "standover" IF the bike has a horizontal top tube. Standover tells you whether you can standover the bike at a red light, and also tells you about how high the bars will be.

With a horizontal top tube, the standover should be about one inch less than your slack's inseam. For example, I am almost 5"10", with a leg length from crotch to floor of 34 inches, and wear slacks with a 32 inch length. So, the road bikes that fit me the best have a standover of 31 inches (for a low bar position) or a standover of 32 inches (for a higher bar position). Most of my bikes with "traditional" geometry measure between size 57 and size 59.

Most guys who are 6'1 would have a slacks inseam of closer to 33 inches or 34 inches, and would need a bike size between size 59 and size 62, unless they want to ride with their bars three or four inches lower than the saddle.

So, with a Trek 5200, a guy with a 33 inch or 34 inch slack's inseam, and a total leg length of 35 inches or 36 inches would get a good fit on the size 60.

biker7

In keeping with what Alan wrote above, I'm 6'1" and would ride a 60cm Trek. I currently ride a 61cm Bianchi and it fits perfectly.
A lot of riders on this forum ride smallish bikes...stiff neck and all.
Good Luck,
George

badkarma

Use the link for wrenchscience and have someone take your measurements and input them into the calculator. See what it tells you, then look at the geometry of the bike you're looking to buy, and see if they match up. Some companies measure ST length from C-C, some measure it from C-T, so it all depends on the geometry of the specific frame you're looking to buy.