I am experiencing some strange phenomenon and would like some opinions about what may be causing this. It's really weird and it's driving me a little batty trying to figure it out.
My bike "A" and bike "B" are running the exact same tire brand, model, size and pressure. They both have 170mm crank arms, identical gear ratios, identical chains, identical rear hubs, close enough to identical front hubs. Inner tubes are identical. The saddles (sit bone dents even) on both bikes are identical distances from from cranks spindle center, as well as fore/aft distance from the crank spindle. Reach is equal on both bikes. All bearings and chains are operating like greased butter. No drag at any of the wheels and both BBs spin like a Top on wet glass.
Here's what's tripping me out. Bike "A" weighs 7+ lbs more than bike "B", and has heavier rims than bike "B". But bike "A" feels much easier to accelerate on. It's VERY noticeable. From a stop bike "A" GOES now and I can achieve 90 RPM with much less effort than on bike "B". That makes no sense considering the heavier rims. Also, if I am already at speed and want to sprint to build more speed in preparation for an upcoming hill, the "burst effort" seems way more productive.
The frame and fork flex are actually greater on bike "A".
The wheelbase is much longer on bike "A".
I thought maybe it was an illusion caused by a nourishment/hydration/different weather/wind thing so I did a same day back-to-back test. I'd ride "A" for a couple miles, immediately jump on "B" for a couple miles, repeat, repeat, repeat, repeat. That only made the difference pronounced, and it aint insignificant. Even hills were noticeably different. "A" happily zipped up them making me feel like some sorta strong quad cyclist dude while "B" reminded me that I am a weak mortal. Bike "B" felt more and more like I was pulling an invisible trailer or riding on flypaper.
The reason I'm so curious is simply because on paper it makes no sense at all, and if I can figure it out maybe I can improve bike "B". I'd also like to understand what's causing this so I know what to look for when choosing frames and components (or combinations?) in the future.
Is there something magical about "A", or is there something wrong with "B".
W.T.F. ?
Any clues?
** I await the "You are stoned", "You are crazy", "Check the ratios", "Get a new Air pressure gauge" comments with great anticipation.
