Steve Sawyer

I'd like to build a bike, something a bit more "casual", more like a touring bike with fenders and a rack. Something to which I won't hesitate to attach a trailer for the dog or panniers for the grocery run.

There's a LBS that always seems to have some "trade-ins" out back (mostly junk, but you never know what you might find in a junk pile), but I figure I can start looking around to find a good frame as a starting point. I'm just not sure what measurements I should look for on a frame to make sure it's at least in the ballpark fit-wise. Obviously SOH and seat tube length are the first things I should check, but considering that it may not have a crankset installed (and will probably be replaced if it does), is there any way of estimating the appropriate seat-tube length based on my inseam?

stapfam

Seat tube length is not the critical measurement. Top Tube length is. With the various frame designs with compact or standard frames then seat post is easy enough to change. But a frame that is too long or short in the top tube will rarely feel right. OK-You could change the bar stem to get the bars the right distance away from you but this could affect the handling or even feel of the bike if the frame is way out on your sizing.

Your current bike fits so measure that top tube length and go for a frame with a T.T. around that length and then look at the frame and feel the weight of it. I know we all want lightweight ones but that may not be possible but a heavy frame made out of Non butted steel with a funny name you have never heard of will not be the best choice. I would also look at rear wheel drop outs and look for the "Modern" version that fits the wheel vertically in the drop outs.

Steve Sawyer

That makes sense - there is adjustment in the saddle height, but not the TT length. Also, depending on the specifics of the geometry the seat tube length should be somewhat proportional to the top tube.

stapfam

Compact frame and is my TCR. Compact Frame and this bike fits perfectly



And so does this oneand this one

Now this never did properly. One frame size too small and seat post not a problem but getting the bars far enough away was. Top Tube was too short but I rode it for a year before getting a bike with the proper size frame with my correct Top Tube length.

StanSeven

I would just measure what you now have and go for something similar - make adjustments based on what you like/dislike about your current bike(s). For example, if you have a road/racing bike and want something more relaxed for touring, you probably want less steep head tube and seat tube angles and a long chain stay. Also don't be overly concerned about too long or short tt - stem lengths compensate and don't affect handling much at all unless you go to extremes like a 70/80 or a 130/140. Do a search and there are a couple very informative threads on this subject.

Many frames are built "square" with the tt and st being about the same. I think that's what you are referring to. That's fine if that's what fits you but I go back to seeing what you now ride and are comfortable with. Also most frames built over the last 10-12 years have sloping tt's so you need to be concerned with "virtual" tt rather than actual. For example the st might measure 52cm but the "virtual" assuming you have a horizontal tt might be 56cm.

Steve Sawyer

Yah - I'm kinda hoping for something more vintage with a horizontal top tube, so that'll have to be taken into account in taking measurements from my current bike.

qcpmsame 

Steve,
Find the thread about Blues Dawg's gravel grinder bike that he built last year. It seems that would fit your descriptions perfectly with some racks added. It will take a wide range of tyres and so far he loves it. Hopefully he will see this thread and give you his thoughts.

Bill

Steve Sawyer

Thanks, Bill - search seems to be broken at the moment but when it gets fixed, I'll check it out.