|Morning Commute -- Going Faster||Gripped|
Mar 27, 2003 9:57 AM
|Since I commute on my Redline Conquest, I figured that this post belongs in this forum. Also, since there have been some posts lately about Armadillo tires and wheelsets, my experience is even more pertenent.
For commuting, I run MA3 rims laced to 105 hubs with Armadillo 23mm tires pumped to 115 psi. I have about 3,000 miles on the tires and haven't rotated them so the rear is getting a way thin. I have a pair of Rolf Vector Comps that I'll use for racing and dry weather rides (I live the the NW so dray weather has been short supply lately).
This morning I noticed that my rear tire had a slow leak. I pumped it up hoping that it would hold enough air for the round trip commute. The past month of riding I felt like I was regressing. I felt slow and my legs seemed to have less pop than they had even a month ago. I headed out on my usual morning loop and felt pretty slow. I noticed that I hadn't fully tightened my front fender after I serviced my brakes last night and I was getting some slight tire rub but not enough to affect performance. I also saw that the rear tire was losing air at an unacceptable rate.
I swung back by my house, tightened the fender, and swapped in the Rolf rear wheel. The Rolf has a Conti Sport 23mm. When I got back out on the road I couldn't believe the difference. I was 2-3 mph faster. The major factors were:
1) Lighter wheel
2) More supple tire (the 'Dillos a SLOW)
3) The 'Dillos were well worn and flattened which increased rolling resistance.
The 105 hub was in fine working condition. I check my hubs once a week during my wash and maintenance session so I believe that the 105 hub was in fine working condition. Thus, I discount worn wheel bearings as a contributing factor.
Moral of the story: If you want to spend money to go faster, buy new wheels and get some supple rubber.
Hasta banana ...
Mar 27, 2003 11:57 AM
|I had a similar experience this morning. Jumped on my commuter, a custom TET steel cross bike equipped with full racks, fenders, heavy CXP 30 wheels and heavy Vittoria Randonneur tyres. About 20 meters from my house, I notice my rear tyre is low, and then I feel and hear rain dropping. Since I didn't want to switch bikes, I swap the rear wheel from my road bike, a lightweight with a 200gramVittoria Corsa CX tubular.
What a difference! I made it to work 5 minutes (!) faster than my typical day. I never knew a wheel could make that big of a difference.
Mar 27, 2003 7:11 PM
|makes the biggest diff. why some vee wheels are, or feel slow. Put's all the weight to the outside, once up to speed they are actually faster (momentum) but climbing and accelerating they can dog.
I notice the diff. between my Ksyrium SCC Sls and my O/P Ceramic Records much the same way. Heavy tires with bad rubber are the worst culprits known. Wheels is the first place to do an upgrade.
Mar 27, 2003 8:53 PM
|They say half a pound off your wheels is like a whole pound off your frame. It's pretty simple really - any weight in your frame (or forks, bar, stem, saddle etc) is being moved forward when you pedal. The weight of your wheels also has to be moved forward, but unlike your frame it also has to be rotated. This means you are powering not only the forward movement of the wheels but also their rotation.
So, a 20lb bike with a heavy frame and light wheels will accelerate quicker than a 20lb bike with a light frame and heavy wheels.
Cranks and pedals are similar, but because they turn a smaller circle the effect is lessened. That is why the importance of weight saving is heightened at the outer limit of the circle of rotation. So lighter rims/tyres are more important than lighter hubs.
So a 1lb wheel with light rims and heavy hubs will accelerate quicker than a 1lb wheel with light hubs and heavy rims.
|agreed, heavy wheels are very noticable||laffeaux|
Mar 28, 2003 11:38 AM
|Last weekend I was riding on the road to a trailhead on my MTB. A large group of roadies came past, and I sped up and began drafting off the rear of the group. I had no problem keeping up with them (20+ mph) utill we hit the first hill, at which point they rapidly pulled away.
The heavier tires of a MTB maike it much slower when accelerating or climbing is involved.
|agreed, heavy wheels are very noticable||atpjunkie|
Mar 28, 2003 2:16 PM
|it's so nice to see people agreeing on simple matters of physics for once. I can't believe the number of flames I've been involved in over such rudimentary science. Also with MTB wheels (or 650's) their smaller size makes them 'top out" earlier. You can accelerate them faster (equal weight wheels, only diff. is circum.) than 700's but they don't hold momentum as well.
The only thing that's funny about all this weight, stuff is I see cyclists spending hunreds of $'s shaving grams whilst they still carry excess lbs on themselves they could remove for free.
Mar 28, 2003 2:42 PM
|"The only thing that's funny about all this weight, stuff is I see cyclists spending hunreds of $'s shaving grams whilst they still carry excess lbs on themselves they could remove for free."
Spending dollars requires a Visa card. Losing weight requires work.
Mar 31, 2003 12:06 PM
|I can put my Rolf Vector Comps on my bike and pick up about one mph in speed right now.
I have ridden 1,600 miles so far this year and I have lost about 11 pounds. I figure that I have increased my speed about one mph.
So I can go faster today by putting on lighter wheels or I can go faster three months from now by increasing my fitness level and dropping some pounds. Hmmm. Another caveat is that eventually, I will run out of fat to lose and increasing my fitness level will require more time and effort than I am prepared to put into cycling. Then I will only be able to go faster by shedding weight from my bike.
Hasta banana ...
|agreed, heavy wheels are very noticable||jedinice1980|
Apr 2, 2003 12:44 PM
|hate to be the dweeb of the post but you are what you are,
momentum doesn't have anything to do with a bigger or smaller wheel radius (when the same weight) - having a smaller wheel accelerates faster because it is like being in a lower gear - one can think of the rear tire itself as the last gear before all energy is translated linearly,
again, apologies for the dweebness,
Apr 2, 2003 2:15 PM
|from one dweeb to another. wouldn't a rotating mass of equal weight but larger diameter spinning carry more momentum. a 700 wheel spinning at 50 rpm covers more linear distance than a 650 at the same speed. I know this falls in your 'gear theory' which I like but it also would carry more as well, no?|
Apr 4, 2003 8:37 AM
|yeah, a bigger wheel with the same weight spinning at the same angular speed would have a larger moment of inertia - which is roughly the spinning equivalent of momentum,
Apr 4, 2003 1:51 PM
|I knew we agreed on this. Ahhhhh Science|
|agreed, light wheels are very noticable||pawistik|
Apr 8, 2003 10:33 AM
|All I know is that on my old MTB commuter when I switch from meaty rubber knobbies to smooth road rubber, it's like I'm suddenly on a whole new bike. The speed I pick up with smooth tires at higher psi is remarkable.
Now I'm wondering how much more commuting speed I can get from my new (used) 'cross bike (C'dale C'cross ultra) by throwing on some smoother, narrower rubber. I'm running ritchey 700x35c speedmax cross rubber right now. I'm thinking of going to some sort of semi-slick maybe about 30c, or should I look for something narrower, maybe 25c? New rubber I can probably afford. A new wheelset is right now too much $$ (though I'm going to keep my eye open for something used or some other sort of bargain).
Bryan in Saskatoon
(The other factor that is causing my speed to increase considerably is the warmer weather - I'm way faster at +10C than -20C.)
|agreed, light wheels are very noticable||atpjunkie|
Apr 9, 2003 4:44 PM
|find some Geax Blades, smooth in the middle with dirt grips on edge. My favorite all terrain commuter tire. Otherwise there are all kinds of good semi's but I hate ruining good dirt tires on a 75% road commute.|| |