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Are road frame sizes based on TT length or ST length?

MMcG

Ride till you puke!
Dec 10, 2002
15,457
12
Burlington, Connecticut
Just curious. I have a 54cm Univega Modo Vivere - bought it used sight unseen figuring a 54 would be fine for me. But the frame is too tall for me - which has me wondering - are frames sized by tt length or st length when it comes to road bikes?
 

LordOpie

MOTHER HEN
Oct 17, 2002
21,022
3
Denver
MMcG said:
yeah the frame is too tall - couple that with 175mm cranks that came with it and it makes for an awkward riding bike for me. :mumble:
huh, I think, typically, 54cm bikes come with 170 or maybe 172.5 cranks. Are you positive it's a 54? Maybe it's a 56-57?

Hey, maybe it's a freak bike... measure the ST, TT, and HTs and since I'm a freak, maybe I'll buy it from you :)
 

sanjuro

Tube Smuggler
Sep 13, 2004
17,373
0
SF
I looked over the Univega site. I could find the exact model, but if it is a compact 54cm, it would probably fit a person 5'11+.

The 175mm cranks is a giveaway for a taller bike, although a few years ago, mid range cranks sometimes came only 170 or 175 (like Shimano 105). What is your height?
 

Pau11y

Turbo Monkey
sanjuro said:
I looked over the Univega site. I could find the exact model, but if it is a compact 54cm, it would probably fit a person 5'11+.

The 175mm cranks is a giveaway for a taller bike, although a few years ago, mid range cranks sometimes came only 170 or 175 (like Shimano 105). What is your height?
Excues my jumping in here, but wouldn't the inseam be a better gague of crank arm length? I mean LO is about 5'8" or 5'10" but he is so leg-long that I'm pretty sure he either has an equal to mine, or longer inseam, and I'm 6'.
 

LordOpie

MOTHER HEN
Oct 17, 2002
21,022
3
Denver
5'8"? ... I'm no midget :blah:

hey, we're heading to Vail this weekend and/or the next. If you're up there, let's do a few runs. My girl's family lives up there :)
 

OGRipper

back alley ripper
Feb 3, 2004
10,647
1,116
NORCAL is the hizzle
It should be based on the seat tube, but the actual measuring points vary. Back when all frames had horizontal top tubes, it was pretty much always center of bb to center of the top tube (where it connects to the seat tube). Since sloping top tube (compact) frames have become popular, there is not really a standard approach. Some still use an actual measurement and some use an "effective" measurement by measuring to the imaginary point where a horizontal top tube would intersect the seat tube. I might be wrong but this sounds like an actual seat tube measurement, with an effective size of 56 - 58. Note also that using actual v. effective measurement will impact the stated top tube length. Last, note that actual measurements can be different from catalog numbers.

So basically what I'm saying is never buy a road bike without swinging a leg over it.:)
 

sanjuro

Tube Smuggler
Sep 13, 2004
17,373
0
SF
Pau11y said:
Excues my jumping in here, but wouldn't the inseam be a better gague of crank arm length? I mean LO is about 5'8" or 5'10" but he is so leg-long that I'm pretty sure he either has an equal to mine, or longer inseam, and I'm 6'.
You're absolutely right, but I was thinking about OEM spec. If there was no 172.5mm crankarm available, a 54cm compact design would probably get a 175mm crank. A 54cm regular might get a 170mm.
 

sanjuro

Tube Smuggler
Sep 13, 2004
17,373
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I own a Seven Axiom Ti (yeah!) and they recommended a compact even though I wanted a standard. I believe it was a 11 degree slope, which I thought would be freaky, but I don't even notice it now.

Compacts initially were a way to minimize sizes (just S, M, L). Many companies have 6 or 7 sizes now.

I think compacts have one huge advantage: fit for smaller people (under 5'9"). Of course, I think there is no advantage for taller people, and I would not even bother with a sloping top tube on the bigger sizes.
 

Pau11y

Turbo Monkey
LordOpie said:
5'8"? ... I'm no midget :blah:

hey, we're heading to Vail this weekend and/or the next. If you're up there, let's do a few runs. My girl's family lives up there :)
Dude, forget Vail. Get you ass to Steamboat. I just got 1st hand reports of 70" in 3 days w/ 2ft more expected!
I won't be going for atleast 2 weeks, last midterms and finals. I also need to get some new rubber for my car so I don't die driving up in the hills.
 

Pau11y

Turbo Monkey
Compacts have their place. For someone like me who's torso long and average or shorter legs, they're great. But for leggy freaks like LO :blah: , he'll have to fly too long of a seatpost to make a compact frame work. And, chances are the headtube isn't long enough so he'll be way to hunched over, or flying a hugely tall stem.
I love squaty long frames on my mtn bikes... it's amazing what an extra inch in the wheelbase adds to stability at speed, and I like to go fast :D
 

MMcG

Ride till you puke!
Dec 10, 2002
15,457
12
Burlington, Connecticut
I did a little more digging - turns out the bike is a 2000 model year and not a 2001 as I thought, and it is a 56 and not a 54. Turns out Univega didn't even make a 54 in that frame in that model in that year. It was either some small sizes then 53 or 56, 57 etc. etc.

This is one trade deal that I got the short end of the stick.

Bike is now up on Ebay. Hope it fetches a decent price. :(
 

Serial Midget

Al Bundy
Jun 25, 2002
13,053
1,896
Fort of Rio Grande
I want to see your new Serotta!!! :drool: :drool: :drool:



MMcG said:
I did a little more digging - turns out the bike is a 2000 model year and not a 2001 as I thought, and it is a 56 and not a 54. Turns out Univega didn't even make a 54 in that frame in that model in that year. It was either some small sizes then 53 or 56, 57 etc. etc.

This is one trade deal that I got the short end of the stick.

Bike is now up on Ebay. Hope it fetches a decent price. :(