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Another "Fit" Question(6 posts)

Another "Fit" QuestionSteve H
Feb 24, 2002 10:45 AM
I have studied all the posts and done all the math and have narrowed this fit thing down. One question remains though. I am a 29.75 inseam and this figures to a 49cc or 50 to 51ct. What the heck is Standover height? If it is the height of the top of the top tube from the ground, some of these 49cc measurements won't leave much room for the boys.
I am riding a 54ct measured to the top of the seat post and it measures about 50.5 to the top of the top tube, and is nestled snugly in my package when I stop. Was hoping to get more room. Thanks for any help you can give me.
re: Another "Fit" QuestionAkirasho
Feb 24, 2002 10:58 AM
Standover height is more of a concern for MTB'rs (where slips and falls are more common) and/or casual cyclists (on hybrids or cruisers) or folks with special needs...

While it's good to have some clearance... your saddle height and top tube length (along with stem reach and height) should be the mitigating factors.

Standover height only becomes a real issue (if all other fit issues have been addressed) for roadies when some other aspect of your ride has gone wrong... i.e. a slip or fall (besides, for some folks the saddle and top tube contact are about as intimate as they're getting ).

We abide.

Remain In Light.
Are you sure you are measuring right?jtolleson
Feb 24, 2002 11:48 AM
If you are successfully, though "snugly" riding a 54 cm frame, 29.75 sounds a little small for your cycling inseam (ie., not your pant inseam). And your shoes should add a little more clearance.

I am a little confused by the measurements you gave of your existing ride.

Anyway, standover height should be from ground to top of tt. For a compact geometry bike with a sloping top tube, the relevant tt spot would be just a couple of inches in front of the saddle.

Sounds like you should spend a little time at a road oriented LBS.
Are you sure you are measuring right?Steve H
Feb 24, 2002 2:07 PM
Thanks for the answer. Yes, I am sure of my measurements. My current bike is a 54 but is measured to the top of the seat tube, and that measurement seems to be a little longer than you might expect. I have been riding it since '97 and have moved enough stuff that I can ride it pretty comfortably. The top tube is just a bit long for my personal comfort but a change of stems made that manageable.

I have talked to people at several bike shops, the nearest I would actually trust is about 150 miles away. I have learned a great deal just reading responses to questions on this board, going to recommended sites and trying the various fit methods. I was just expecting more clearance from a bike sized by the .67 or .65 method. As was suggested, I might have more clearance in my shoes and on the actual bike rather than just reading the mfg specs.
how to check clearance...C-40
Feb 24, 2002 3:41 PM
Dress in cycling shorts and bare feet. Block up the wheels of you current ride until the top tube exerts firm (saddle like) pressure in the crotch, not just brushing your shorts.

A frame that is sized properly (vertically) will have 2-5cm inches under the wheels. I get very firm pressure on my bike with a standard 2 x 4 (1-5/8 inch actual thickness) under each wheel. I figure the clearance to be slightly less than 4cm. For reference, my saddle sits 17mm above the top tube. This height yields a saddle to bar height difference in the 9-10cm range, using an 80 degree stem, with no more than 3mm of spacer.

A serious racer might select a frame that was 1cm smaller and a touring rider might select 1cm larger. Notice that I'm only talking about vertical sizing. Horizontal size must also be considered (top tube length and seat tube angle).
Good stuffTroyboy
Feb 25, 2002 8:41 AM
If you don't have clearance your fit is not optimal and can be improved.