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Spinchick's sizing problem - questions...?(9 posts)

Spinchick's sizing problem - questions...?UncleMoe
Aug 28, 2001 8:20 AM
I was reading the thread yesterday about Spinchicks saddle problems and someone asked about how well she thought the bke fit her. To make a long story short, some made a determination that perhaps her top tube is too short, so too much of her weight is out front over the front wheel, plus she is sort of cramped into the bike.

All this got me to looking at the geometry of my bike and now I am curious. I am 5'7" (5'8" on a good day). I ride a 52cm Bianchi Brava, and the top tube is 53cm. This is the first road bike I have ever purchased as I have ridden MTB for 10 years. When I am in the drops, my nose is actually slightly in front of the stem and I can easily see the hub. The view of the hub is only obstructed when I am "sitting up" in the saddle, i.e. not in the drops or extended onto the flight deck (not sure if using right terms).

Is this bad? It is comfortable, but at times I feel like I am too far forward, but my seat won't go back anymore without really messing up my peddle stroke, never mind that it become uncomfortable.

I should add this. I bought the bike mainly for commuting with a pack on the rack. It is also sold as a touring/commuter bike, not intended as a race bike. Perhaps its not really intended for me to be in the drops too often or at higher speeds. Plus, since I usually ride with a loaded pack, my weight needs to be more forward to compensate for weight on the back.

Do the geometry rules change depending on your intent? Are my above assumptions correct?

Thanks.
re: Spinchick's sizing problem - questions...?Jon Billheimer
Aug 28, 2001 9:13 AM
The basics of fit don't change. However, for a commuting bike you might adopt a little more upright position (e.g. smaller seat/handlebar height differential) than for racing. Also, a touring bike will have a longer wheelbase than a racing bike, for the purpose of stability while carrying loaded panniers. Since you are only commuting on this bike and are experiencing no discomfort, I wouldn't worry about the top tube/stem length issue too much unless you feel the bike's handling is compromised. If that is an issue or your feel overweighted over the front wheel, which it sounds like you are, you can always try going to a longer stem, up to about a maximum length of 130 mm. However, if you buy another road bike you would want to dial in your fit a little better.
re: Spinchick's sizing problem - questions...?vanzutas
Aug 28, 2001 9:22 AM
Jon, How will putting a longer stem bring weight back on the bike? His weight will only go more forward with a longer stem.
re: Spinchick's sizing problem - questions...?Jon Billheimer
Aug 28, 2001 9:28 AM
You're right, it won't fix the weight distribution problem, but will "uncompress" him over the top of the bike, hopefully making him more comfortable. From my understanding, anything longer than a 130 mm stem will create real twitchy handling problems.
Sounds to me like your bike might be on the small side.Spoke Wrench
Aug 28, 2001 2:32 PM
My first question would be: How much seat post do you have sticking out of the frame? I'm betting quite a bit 8" to 10" or so.

While everybody likes to talk about top tube and stem length, I think that the biggest problem with a too small frame is that the handlebar is too low. That changes the angle of your crotch on the saddle and stretches your torso out over the handlebar. See if you can find a way to raise your handlebar a couple of inches.
Actually, not much is sticking out...UncleMoe
Aug 28, 2001 3:14 PM
Thanks Spoke Wrench. I actually only have about 4/5 inches tops of the seat post sticking out of the frame. I'm wondering if I have an oddly proportioned body or if my bikes geometry is weird. I looked at the kevinlippert.com (sp) site that was recommended and he suggests a frame where the top tube is 2-3cm longer than the stem length. My Bianchi is 52cm/53cm top tube.

I was thinking about that on the ride into work this morning. Maybe I should at least try a riser or two on the handlebars. Couldn't hurt to try.
I'd try raising the bars a little.Spoke Wrench
Aug 28, 2001 6:52 PM
It will change the angle of your torso and make your bike feel longer.

Back in the olden days when men were men and headsets were threaded you could more easilly experiment with handlebar height than you can today. You might try Spinchick's trick of flipping your stem upside down to gain a little height. Sticking a spacer under your stem probably isn't going to work because your stem will be too high up on the steer tube.
speaking of which...Spinchick
Aug 28, 2001 3:23 PM
I was not able to raise my handlebars without a riser. So I turned the stem upside down. The angle (now upward) adds an a little over an inch of height. It's only a temporary solution until I: a)get a riser, b) get a new stem (although this one's fairly long) or c)get my new, custom-built bike this winter for Christmas or birthday depending on how soon Hubby wants to make me happy :-)! Then I'll keep this 22 pound hunk o' steel for the trainer indoors. Thanks for your advice Spoke Wrench.
So how's an inch of rise feel? (nm)Spoke Wrench
Aug 28, 2001 6:25 PM