(This is my first post.)
Without doing my homework I purchased a Raleigh Venture (the basic model not a 3.0 or 4.0) from a bike store in early 2009 and, after not using the bike much, I put it up until just the past few weeks. (If I'd known then what I'm realizing now I would have purchased a Venture 4.0.)
Now I have begun to ride the bike every day (usually just after Sunrise in an attempt to escape the scorching summer weather we're having here in the Dallas area) and have come to the conclusion that the gearing isn't well chosen.
(I don't know 'bicycle-ese' so please forgive if I drop into 'Engineering-speak'.)
As best I can tell the bike is set up with far too low gearing ratios. The Venture has only a single sprocket (40 teeth) on the crankshaft and the rear gearing consists of 7 gears (14 through 34 teeth).
I never use the lower 3 gears as they are totally unusable and spend 90 percent of the time in gears 7 (highest) and 6.
The Venture was not built to accept a replacement Chainring (Chaingear) but it looks to me as though it wouldn't take much to bolt a new Chainring up against the existing assembly (the protective shrouds around the gear are attached with mounting holes that are almost exactly 110 mm spacing - they appear to be slightly less than 3 mm greater in radius).
My intent is to get a replacement Chainring with 50 teeth and bolt it up against the existing 40 tooth gear (the teeth of which are an integral part of the hub). The 50 tooth Chainring will have a radius 25 percent greater than the existing teeth and so should stick out-in-the-clear.
(I think that there may be sufficient available chain to accommodate the 50 tooth gear's diameter but if not I'll put a longer chain on.)
Is there anything about this idea that won't work ? It looks to me like a pretty straightforward thing to do. (The bike shop, where I bought the bike 2 years ago, wants to replace the entire crank assembly and that seems completely unnecessary to me; also rather expensive.)