*sobbing*
*removes his spokecards*
*hands head in shame*

Lol!

:lol: It was 44 degrees this morning at 7AM actually.

Another thing to ponder is that the two people in our office that bought bikes specifically for commuting didn't get an ATB, a road bike, or even a cross bike.

One got sort of a half recumbant and the other got a "Trice" (trike). Of course both of them spent a lot more for their bikes than I did.

Neither of bikes I use for commuting were really purchased for that purpose, and I realize that my preference is geared not only to the type of commute I have, but to my other bicycling needs/hobbies.

My commute is not just how I get to work. It's also exercise and training for the couple of triathlons I do a year. That two mile stretch of uninterrupted trail in the middle of my commute is pure joy on the road bike and frustrating on the MTB because I can't maintain the pace I want. If my commute was mostly downtown, the speed advantage of the road bike would be almost irrelevant. Funny thing though is that most of the messengers downtown used Fixed Gear road bikes.

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.

44x18 or 44x16 on my SSx2 MTB, which I have been informed here is a heretic-mobile.... :lol:
And yes in the short term it does seem to accelerate faster than my 48x16 SS Paké

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.

On my commuter road bike (700c) my large front is 54t and my rear gearing is more like a touring bike..... 12-26. I pretty much never ride in my small chainring so I won't mention the size. Only time my chain is on that ring is for a two minute warm up and cool down, or on the off chance I cut cross-country for a short distance.

Our street conditions are so poor in general that staying in the large chainring eliminates a lot of chain slapping and ghost shifting when hammering along on these Paris-Roubaix surfaces. I take routes on 700x23c tires that friends of mine won't even ride on 700x32 rubber. They won't use ATB fattys either, cause it is too hard to keep up with traffic - some routes are "do or die" fast cycling required. When I sometimes try my ATB on these routes I spin out in my tallest gear, wishing I had one or two more. Horns are ablaze and fists clenched if I drop much below 25mph on some hellish roads.

To answer your question with an OPINION....I don't think ATB gearing would be advantageous for me on my current commute. I am out of the saddle from every stop, so I never drop down to my smaller ring once the battle begins.

Do you think that's because of wheel size or riding position? I think I accelerate from a dead stop better on an MTB too but I'm not sure it's because of the wheels.

out of curiosity... how often do you pinch flat those 23's? Mind if I ask how much you weigh? what type of rims & rubber do you use?

i'd like to plug your numbers into the interia calculation and see what I get compared to my setup ;)

edit: interesting setup with the big ring & wide ratio cogset on back - how much do you use those lower gears?

cheers

Gearing, and the wheel size. Just easier to turn it over from dead stop IMHO.
As it is in the snow I'm runnin' 2.1 inch knobbies now, and glad for it.... whew what a dump we got.

I'm in a pretty low stretched out position on both bikes (actually a bit too long but... that's to remember when buying a NEW BIKE in 08. Both have a decent saddle to bar drop.

Parallel thinking/different end result! I'm the same: my bike 'passion' is riding relatively non-technical (in deference to my age/abilities) singletrack 'in the woods' -- that's why I have an 'atb' -- and use my commute to get to work and, like you, 'practice'! Here, though, my commute is either right smack on very bad roads/in heavy traffic, or on a very poorly surfaced, very heavily used MUP that runs along the river, and which has singletrack running parallel for long stretches right along the river. So, the slicked-up atb works perfectly in that composite environment: a lot of stop/go, on/off/on pavement, twists/turns, emergency avoidance etc. Roadies around here tend to avoid the MUP itself for good reason!! Riding road is, for me, base fitness/endurance prep, and I tend to ride out into the countryside and onto county roads asap!!

So much of anyone's answer depends on their personal and riding circumstances. My ten mile commute is on a MUP and over half of those I see while I'm riding are on road bikes, probably closer to 80% today (eight out of ten this moring). When we had warmer weather, I saw a broader mix of bike types. Clearly with the cold, I may be seeing more serious riders. I'm riding what I had, a rigid Raleigh M60, but used a road bike to ride about the same distance on streets in Atlanta 20 years ago. Not many mountain bikes available then and it was what I had. I've only been regularly commuting for three months this time and I don't want to invest in a new bike until I'm sure I will keep at it. Even so, for my commute, I do prefer the more upright position in the MTB. I've ridden the same route on my old road bike and was only one or two minutes faster. This way I keep the bike lights, rack and other weight items on only one bike. However, I've changed my tires to the Kenda Cross Plus with smooth center tread and knobbies on the side. I've just mounted a pair of Schwalbe Marathon Winter studded tires to a spare set of wheels after a couple of days of snow and ice.

Are you riding from Spencer to Bloomington. What's your route and distance?

You know one thing I've kept hearing through this whole discussion is people worried about flats with road bikes. I've run anywhere from 23's to 28's and never had a pinch flat. My understanding is that unless your tire is underinflated or too narrow for the rim, the chance of getting a pinch flat is pretty small. My weight runs between 150 and 160 FWIW.

Intuitively I understand the fear but I heard one comment that any gain in speed from using a road bike is lost in changing flats. I'd have to have flat almost everyday for that to be true. I've seen other people change flats, I've had slow leaks due to a tiny puncture but the one blowout I witnessed on my commute home happened to a guy running knobbies on his MTB.

My brother gets flats all the time on his MTB and doesn't even commute, though he does ride a lot. He is slightly over 200 lbs.

I can't resist: here's an Inertia calculation:

I=MR^2
Diam Diam
MTB 22 Road 24.5

Mass (atb/road):

rim 400 rim 450
tube 150 tube 150
tire 350 tire 300
total 900 total 900

MTB Inertia 10.89 Road Inertia 14
road = 124% mtb

This shows the road bike has 20-25% more inertia in the wheels.

Assumptions:

-Discounts the spokes, nipples, hub, etc. Inertia is related to the square of the radius, so stuff close to the center of rotation doesn't matter much anyway.

-uses the "true" diameter of mtb rims (22") and 700c rims (24.5")

-rim: nice mtb rim of around 400g, nice road rim of around 450g.

-tube: i figure about the same for each, around 150g

-tire: i used the "Nashbar Slick" wire bead 26x1.25 and Duro Road folding bead 700x26c tires. about what the *average* commuter uses... just a guess cause I havta put something there.

the "inertia" number is just an index to compare one to the other. feel free to plug into your own spreadsheet & play around. edited for readability - copy/paste from execl to bf is iffy.

Nobody told me there was going to be math involved!!!!!!

sorry, my inner geek got out:rolleyes:

I think your numbers might be a bit skewed. I'm guessing an "average" MTB commuter is not running that small of tire. Also, it depends on what you consider "nice" but I don't think 450g is particularly light for a road rim. Don't know much about nice MTB rims.

You might get truer results not using the diameter of the rims but the outside diameter of the mounted tires. MTB tires tend to be much taller though I don't know about the tire you selected.

In my case, I have 1.95s on the MTB and the 23s on my road bike so the numbers are going to be quite different.

What about Recumbents? I use my Bent for my commute and it's great. I have 1.50 100psi tires. A nice compromise of contact and pressure. I feel that when riding my bent I'm more comfortable then either my mtb or roadie. I'm faster than on my mtb and a little slower than on my roadie. In the winter I can slap on the windscreen and stay much warmer than without. I've got a rear rack, panniers and a windscreen so in terms of weather protection and load hauling I'm set. Ok I can't jump over curbs but I haven't had to do that in a long while. I store mine in the office which is a pain to maneuver it around but you can't have everything!
http://img91.imageshack.us/img91/414...61largegt3.jpg
By domromer

Oh and there is a sputtering trend in the road bike world to move to a 650B sized wheel. ;-) I think the following is limited.

One word: Elevator ;-)

sure, all points are valid, 'cept the "average" mtb commuter hasn't voiced up yet, so i don't know what they use! I took a guess based off what i've used & seen used. personally i've gone all the way down to 195g, 1" tires, and up to 600g 2" tires.

feel free to plug this into your own spreadsheet & play around. it's facinating seeing how much of a difference lowering the rotating mass makes. if you have numbers for your setup I can plug them in.

I use Hutchinson Acrobats on my commuter. I think they're 1.9 or 2.0, can't remember. Not sure on the weight, but they feel at least as heavy as a 2.0 Big Apple, which I believe is over 800 grams.

Yeah, that's complete rubbish. I've ridden almost 3,000 miles this year and at least 2,000 of that is commuting and all of it was on a road bike with 700x23 tires. I've had exactly 2 flats and only one of them was on a commute home. I keep my tires properly inflated and check them frequently and I am always watching the road ahead for hazards but even so I've run over glass and other debris but overall I have very few flats on a road bike.

BTW-My entire front wheel weighs about 630g (without a tube/tire). :p

I weigh 150lbs. I am a very "light" rider as far as the abuse suffered by my road bike components. I don't normally just slam into things and stay light in the saddle all the time. I don't put much weight on the saddle, esp on rough surfaces and usually pedal a very tall gear to help keep my arse safe from the hammering saddle.

Vredestein Fortezza Tri-Comp tires. 700x23. No (undeserved) pinch flats. I run between 120 and 130psi on some very old Mavic Reflex 36 spoke conventional wheels. Not all that light, but bombproof - and not total slugs by any means.

The tires are not "Race Day" tires, but one step heavier. The "Tri" stands for Three elements - 1. Hard center strip for speed going straight, 2. Gooey side strips for a-m-a-z-i-n-g cornering even on wet roads. The tires are billed as All-Weather tires. 3. A strip of "kevlar" type flat prevention that works well at holding the tread together even after a nasty gouge.

I have three flats since August, two of them last week. Rare otherwise. The August was a pinch flat on the front tire from hitting the gate track at my old apartment complex waaaaay to fast. I shot a gap in traffic and wacked the sharp edge at 19-20mph. Went flat overnight. The next two flats were glass bits and both on the front tire! (hence, my new sig line). Never had three front flats in a row before. Got the last two flats on wet streets, so probably some broken glass that I continue to not see and run through.

I try to stay in the auto tracks. Too much broken glass and building materials on the road in New Orleans to ride in the "gutter".

I almost never use the lower gears. But when I do, it's nice to have them. There are some sweet short cuts around town that require a bit of off road riding through mostly mowed grass, but it varies. Probably could make due without the 26.

BTW...no snow and ice down here pretty much EVER. If the streets where a mess with frozen precipitation tomorrow morning I would ride my Pugsley to work and ditch the 23s big time.