francypants

Hello. Just had a quick question about how to accurately measure a frame's height? Do I start from the middle of the bottom bracket and then take it all the way up to the top of the tob tube? I thought I was a 53cm frame since I'm around 5'8" with normal inseam, but the top tube of the frame I have is digging into my jewels (no clearance at all) and so I'm wondering if I need a smaller frame or if the frame is not actually a 53cm. I was told a good 1-2 inch clearance from the tt to the groin is standard. Is clearance really not important?

zip22

if you plan on never standing over your bike then its not important. you could manage if you track stand all the time and hop onto and off of your bike while still in the pedals.

it sounds like you've got 53cm stuck in your head. if it doesn't clear your balls, i think its too big for you regardless of what size you 'should' be. bikes are either measured center to center or center to top. the first being the bottom bracket and the second being at the place where the top tube connects with the seat tube. but that doesn't account for how high the bottom bracket is from the ground.

Ceya

yep clearence is important, jump off the bike and on the toptube while the bike's in motion . there is your answer.

there is no normal inseam. the rule or say in the rule is take a stick place between your legs up to the crotch level measure from the top to the ground.

yes 1 to 2 inch rule does apply if you cannot do the above. maybe Don Walker will chime in later.

S/F,
CEYA!

bostontrevor

Measure center to center from the BB shell to the top tube. If this is a track bike, you may very well have a 53cm frame but with a higher-than-road bottom bracket. I'm 5' 8" (with a 31.5" inseam) on a 54cm bike and not only does the TT hit the jewels, it actually digs a little into my pubic bone.

In practice it's not a problem other than having to swing my leg over a little higher. The rest of the time, I can just tilt it off to the side to get it a little lower while just standing around. I don't know about you, but I don't spend a lot of time with my feet on the ground when I'm riding.

baxtefer

standover is overrated.

is the TT the right length?

noisebeam

Yep. I ride a 61cm frame that I can not straddle barefoot without some serious pain, but the reach is perfect. I also ride a 57cm frame that gives a couple of inches of standover clearance and also has a perfect (and identical as the 61cm frame) reach. I've never had a need to straddle a frame with the frame kept in a perfectly vertical orientation. Note you most always tip the frame to the side when unclipped and waiting to go.

Al

baxtefer

^ yeah, and who rides barefoot?

noisebeam

Point was there is significant interference barefoot, add the thin sole of a typical bike shoe and there is still some interference. I mainly use thicker soled Shimano sandals, so it ends up being about a 'perfect' fit. By perfect I mean that I can tell if I'm standing over a cable guide braze on or not.
Thats why I said barefoot, to eliminate the sole part of the equation.

Al

baxtefer

yes yes I understand
i was just trying to reinforce your point.

my commuter is "too big" for me. it's a 62cm c-c traditional geometry frame. I have short legs for my height, so for satndover, i should really be riding a 57. Unfortunately a 57 would have waaaaaay to short a reach.
I have 0 standover barefoot. and mabye 1cm or so with shoes on.
I have yet to sack myself with the TT.

adamkell

This is good to hear, as I just bought a frame that's a bit taller than my others and I was somewhat worried.

drac_vamp

i give refunds

adamkell

But I'm bullheaded. I'd just ride in very tall shoes.

[/hijack]

noisebeam

Yeah, I got it. I have a 'bike fit' inseam of 33.5" and the top edge of the top tube of my 61cm bike is 89cm (35") from the ground. I am 6'2" I think I have shorter legs that typical for 6'2"

Al

baxtefer

you're exactly my size.