Originally Posted by
acroy
Does anyone else consider the gearing of the MTB an advantage over their road bike for commuting?
I have a fairly flat commute with lots of stops. I never have to leave the big ring - generally start out from lights in 3rd or 4th, which is plenty low for good acceleration.
On the high end, i'm generally cruising in 6th or 7th (out of 9 total). I occasionally spin out 9th at around 30mph down the one hill. so out of 27 gears, only 5 or 6 get a lot of use. but those 5 or 6 are perfectly geared & spaced for what i have to do. i only keep the other rings on the crank for the occasional family outing / towing duty
on the road bike i find myself going up & down b/w the big & small ring. A lot! Small is too small, big is too big, and the difference between cogs in back is (relatively) tiny.
i think the optimal bike for the elusive *average* commuter, with a decent route on decent roads, might be a disc-brake cross bike, maybe a single ring up front, and a mtb cogset in back.
Another point to consider is that my back o' the envelope calculation indicates that 26" wheel with slicks has around 20% less inertia than 700c. Anyone else feel that their road bike accelerates slower? It might be true... this would indicate smaller wheels are "better" for stop&go commutes. of course, there's a lot of variables in the calculation, and I'm probably just fooling myself with lower gearing on the mtb.
Probably too many variables to generalize but...
Everything being equal smaller wheels might be better for stop and go but the wheels on road bikes are often lighter with less weight out at the rims and tires which would make them easier to spin up than a heavier wheel. Also, the larger diameter of the 700c wheel can be compensated for by using a lower gear.
My MTB seems more sensitive to changes in grade and wind speed so I shift more, not less on the MTB. I also tend to spin out on the high end more easily on the MTB. I very rarely use the smallest chainring on the road with the MTB but I do switch between the top two chainrings if for no other reason than I try to avoid cross-chaining.
Rear gearing is one thing that's relatively easy to change on either MTBs or road bikes so while there are general tendencies, you can often compensate.