's Forum Archives - General

Archive Home >> General(1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 )

Roller related numbness. What gives.(12 posts)

Roller related numbness. What gives.Sintesi
Nov 4, 2002 11:36 AM
I never get numbness when I regularly ride. I have a trans - am saddle w/ the cut-out never been a problem. Now that I'm logging in time on the rollers I get this dreaded syndrome in about 20 minutes. Explanations? Suggestions?

BTW, I have been riding these for about a week.
re: Roller related numbness. What gives.Allez Rouge
Nov 4, 2002 11:44 AM
If you're new to riding rollers (one week total?), maybe you're all tensed up, not relaxing as fully as you would when out on the road?

Presumably you're spending the whole 20 minutes in the saddle (I've heard that it's possible to stand up on rollers, but I've certainly never tried it). How does that length of time compare to how long you'd stay seated at one stretch out on the road? I would guess that I'm out of the saddle for at least a few pedal strokes every ten minutes or so, maybe even more often than that.
re: Roller related numbness. What gives.GMS
Nov 4, 2002 11:51 AM
There is more weight on your seat because there is less weight on your feet. Your pedals are pushing back on your legs with a lesser percentage of the force you apply than they are in real biking. This is because rollers move and the ground does not. If your rollers were perfectly frictionless (and you are not accelerating), then riding on them would be nearly equivalent to sitting on your bike with your legs dangling to the sides and not touching the pedals.

Try moving around on the saddle a lot, sitting up more, and learn what positions are associated with discomfort. Additional weight distribution on the saddle makes slightly uncomfortable positions more uncomfortable, but a perfectly comfortable position isn't affected by weight that much. In many cases, people sit in uncomfortable positions while doing real riding, but the weight on the saddle is so little (for various reasons) that it seems comfortable, initially.
If rollers were frictionlessPODIUMBOUNDdotCA
Nov 4, 2002 1:34 PM
Just out of curiousity if rollers produced so much less friction than the road then why is your hr at a given speed roughly approximate to that on the road? I'm not sure if I agree with your theory.

Depends on the rollers, of course, but I have attained a "speed"bill
Nov 4, 2002 2:06 PM
of 50 mph on rollers. At no risk of selling myself short, I assure you that I could not pedal my bike on a flat anywhere near 50 mph. So, rollers may not be resistance-less, but it ain't hardly the same.
If rollers were entirely resistance-less, the limiting factor in speed would be gearing and leg speed and, I guess, some wind resistance from spoke movement. But they create more resistance than that. From where?
From the tire resistance, which is probably greater on rollers. Because of the shape of the rollers, the contact point of the tires is smaller, creating more resistance. So, some resistance from spoke movement, some more from tire deflection. But you still can go lots "faster" on rollers. Why?
Because of the lack of wind resistance on rollers, of course. Wind resistance, don't forget, increases by the square of velocity, so, at speeds in excess of like 15 mph wind resistance becomes a factor and at speeds in excess of 20 becomes huge.
My own experience is that I have a wind resistance unit on my rollers (the standard Kreitlers). With the unit set on, according to the very rough gauge on the unit, a headwind of, say, 2 mph, I cannot maintain speeds that I believe I can maintain on the road in a real headwind. But that's with a resistance unit, and I have to believe that the inaccuracy of the little gauge accounts for the difference. I assume that they accounted for tire deflection, but maybe not.
The wind resistance unit is kind of cool because the resistance increases with the square of velocity, just like on the road. On rollers without such a unit, the resistance, generated solely by the tires, increases linearly.
If rollers were frictionlessGMS
Nov 4, 2002 3:03 PM
Rollers are not frictionless. We can make better examples through extreme comparisons. Since rollers are slightly less than frictionless, the weight on your seat is slightly less than it would be if you dangled your legs to the side.

Another example is if you got in 53x11 at almost 0 mph and took a half-stroke as powerful as could, the force that the pedal pushes back on your foot with would be much stronger on pavement than it would be on rollers.

In addition to all that, the weight supported by your legs is much less if you are spinning easily and consisently, with little or no acceleration. This is true both on the road and on rollers. But on rollers, many people spin easily almost 100% of the time, whereas on the road people's pedalling is much more varied because of hills and circumstances in which they need to accelerate.

Weight distribution is not the only cause of the problem in question, but it is nearly impossible for there to be less weight distributed to the saddle when on rollers compared to the road, and it is quite likely that there is more.
re: Roller related numbness. What gives.firstrax
Nov 4, 2002 6:14 PM
I agree with the first part of GMS's post. I hand a lot more discomfort on rollers than on the road. I put a resistance unit on my rollers and now I can put more pressure on the pedals and less on my butt. Still not brave enough to try standing though.
Two things: One, more time in the saddle without a break. Two,bill
Nov 4, 2002 12:09 PM
it is also possible that, with the low resistance of rollers, you aren't pushing down as hard on the pedals, so that there are fewer oppositional forces lifting you off the saddle.
Lifting your butt off of the saddle is difficult but not impossible. The trick is to realize that you can't just stand up. Basically, you lift your butt off of the saddle a few cm by pulling yourself forward with your arms, keeping your weight balanced more or less over the saddle. It's also hard to do it for any length of time, but short breaks every five or ten minutes can make a huge difference. About every ten minutes or so, I try to lift my butt up for about a minute total in ten or fifteen second segments, sitting down to rebalance for a moment between segments. I never have tried to set a personal standing record, but my guess is that I couldn't hold it steady for any more than about 30 sec's to one minute.
re: Roller related numbness. What gives.wilsonc
Nov 4, 2002 12:43 PM
I'm relatively new to rollers as well, and i've found that if i stop every 5-10 for about 30 seconds to lean against the wall (not pedalling) that it makes an hour tolerable.... It also helps break up the monotony. I figure if i only stop pedalling for 30 seconds or so, it is just like coasting when riding outside.

Same problemPODIUMBOUNDdotCA
Nov 4, 2002 1:37 PM
I hate it. I just stand up which makes it more bearable but not completely. Ugh...

I'll post above my advice on standing.

At least I know the trans am won't relieve my pain so I can save that cash.

Same here..MXL02
Nov 4, 2002 4:42 PM
I believe it has to do with spinning without moving on the saddle...when on rollers you don't move your a$$ or stand and coast like you do when riding, so you have longer periods of unremitting pressure. I just do 15 minutes at a time, rest 5 minutes, then go at it again. I don't believe there is any other good solution.
Thanks all.Sintesi
Nov 5, 2002 5:40 AM
thanks for the explanations, advice and the empathy. Well last night I tried getting off the saddle a couple cm as bill suggested and I didn't do too bad. Definitely helped. As I go into week two we'll see how much I improve; every day seems like a step forward in stability.