power question

[CR400]

Ok, I don't really know how to ask this but. Have any of you ever had the problem with literally pulling the front end of your bike off the ground on high power/speed climbs? Sometimes it is so bad I wish the bike was about 40 pounds heavier so I had something to offer resistance besides my butt in the saddle. Or another one I have when I do high power starts or suddenly increase power out put significantly, I tend to throw myself up out of the saddle on each pedal stroke, until I find a gear big enough offer enough resistance to keep me in the saddle. You get a sore butt at a high enough cadance . Not that I'm super fast or anything just curious. Any ideas why this happens?

[KnottedYet]

It happens to me if I yank on the bars while pushing on the pedals. If I lighten up on the bars ("playing piano"), drop down a gear, and concentrate on just using my legs to power up the hill I seem to be more efficient.

But then, my idea of powering up a hill is 26T chainring and 34T cog and 5 mph...

[Wahine]

I assume we're talking about road riding here??

If so I would try to do what Knott said. Play with your gearing and get better control in the saddle.

In mountain biking on steep pitches you actually have to drop you chest towards the handle bars in order to keep enough weight on the front wheel. I imagine you could do the same with a road bike but you should still be feathering the handlebars as much as possible.

[Thorn]

I have this problem when the road gets really steep.

But, I read somewhere that if the bike isn't fit properly that this will happen. I believe it was something about if the bike is too long that your center of gravity is too far back, causing the front end to pick up on hills. It also affects the stability going down hills. So, besides what Knotted said, you might want to check the fit (or wait until one of the gurus comes on and tells me I shouldn't believe everything I read? I can be so gullible )

[RoadRaven]

None of us in the house have had this happen to us, but the first response from my partner when I asked about your post is

"it sounds like the frame is too big for her"

He also suggests shifting your seat further forward and put a longer stem on the front to shift your centre of gravity further forward.

Good luck

EDITED: My partner says he has had the front wheel lift on a climb before, but its on a REALLY steep climb, and only when he is seated.
(REALLY steep being a 15% or more climb)

[CR400]

Thanks ladies. I think I may not realize that I am pulling up on the front end of my bike. It never happens out of the saddle, infact the opposite happens. I've unweighted the back of the bike enough to cause the rear wheel to skip and lose traction. The first time it ever happened I just about fell over the handle bars.

What about the high power starts? I'm I starting in to low of a gear so my cadance goes out of control throwing me around?

Oh, Roadraven! Usually to me it feels like the bike is to small when I am trying to stretchout on the top tube to get more aero. My rear usually ends up being an inch or two off the back of the seat. I think 4 to 6cm in metric. And there are times that it feels a little big such as crank length and seat tube.

[Eden]

hmmm - you say it feels too small - the only time that ever happened to me was when I was riding a bike that was too long, going up very steep hills.

I have to be very careful when sprinting to keep enough weight over the back of my bike or else it will skip - though I've never almost tossed myself off.

[CR400]

The day I lost traction on my bike was a steep climb in my area only maybe 10%. I was standing trying to apply as much power as I felt the hill needed and apparently stood to far foreward and caused the back wheel to leave the ground. leaving the chain to keep rotating with no resistance, hence applying power against no resistance, foreward I go. Ooopps okay don't lean that far foreward while standing. Would have been good position for a flat sprint.

What I may be really asking is why in a max (full power) seated sprint up a hill the lifting happens? And why I litterally throw my body out of the saddle on the down stroke in a max (full power ) seated sprint?

Maybe I'm strange and you all apply max power differently. There have been times in the past in a full biggest gear sprint I feel like if I'm not careful I will seriously pull/tear ligiments and tendons so I back off. 15mph to 27 on a great day 30mph, feels like a very violent and potentially bad thing, not to mention very exhausting.

[Eden]

And why I litterally throw my body out of the saddle on the down stroke in a max (full power ) seated sprint?

Maybe I'm strange and you all apply max power differently. There have been times in the past in a full biggest gear sprint I feel like if I'm not careful I will seriously pull/tear ligiments and tendons so I back off. 15mph to 27 on a great day 30mph, feels like a very violent and potentially bad thing, not to mention very exhausting.

hmmmm - I really think you should look into getting a comprehensive bike fit. It sounds like it is probably a combination of fit and technique? My first thought was that maybe your cranks might be way too long - hence the feeling like you are throwing your body forwards on the downstroke? It might explain the problem you are having with un-weighting the rear wheel- if your cranks were too long, standing you'd put too much weight over the front of the bike and the rear wheel could slip. You should be careful when sprinting of leaning too far forward - especially now that bikes are very light, and I certainly have this problem, if you lean too far out the rear wheel will slip. It is more common on smaller wheel bikes too, so if you are riding 650's you have to be doubly careful. I have sprinted at 30 mph and above in the past and I never have felt like I am going to do myself any injury - but yes of course it is completely exhausting. That's not to say it doesn't hurt - sure it does, but its not the kind of hurt that feels like tearing anything - its just the used muscle kind of hurt, if you know what I mean?

[CR400]

Not foreward, up like I'm on a stair master. When I'm on the down stroke the leg pushes down hard enough to lift me off the saddle and I'm trying to sit. Until I find a gear big enough to offer enough resistance I can stay down, get tired, or slow down. I also have found many times I may not come out of the saddle but hover just above, I barely have contact with it.

As for fit, two shops have given my numbers for what I should ride and both agree on frame size and such. Both men were from different states even. So it is usually how I sit on the bike. I tried riding a smaller frame for an LT test on a compu trainer. I felt so tight like everything was to close, plus boy did we have to put the seat up. Same thing when I rode a 50cm bike at the shop. My friend who has been riding much longer then me asked how it felt. I told him cramped. Which was what he thought to watching me try to ride. So I got a 52cm.

[KnottedYet]

CR400 - this may be a really dumb question, so forgive me, but do you have your saddle too low and are you mashing in too high a gear?

The things you describe sound like a saddle too close to the cranks and pushing too large a gear to me. (bike feels too small sometimes, bike feels too big sometimes, pulling power from the bars, wheels unweighting, butt coming off the saddle in different situations)

It might be something really subtle, like just a half inch or so, or one gear or so, but with the power you're putting into the bike it might make a big difference.

Or I could be completely off base! Just a thought...

Knot-who-rarely-goes-over-20-mph