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another whacky idea(20 posts)

another whacky ideaDougSloan
Jan 11, 2004 2:24 PM
As I was descending a 4,000 mountain yesterday (yes, really) on my fixed in a 41x16 I thought it would be great to have a training device to simulate fixed descending at home. Possibly, I could hook up a motor to a trainer, then have some sort of throttle and run the speedo off the rear wheel. I can presently sit and spin comfortably at about 27 mph, which is 133 rpms, for extended periods, but I'd like to gear a bit low and raise my comfortable (not max) spin speed to about 30 mph, as much as 150 rpms. Of course, training for this might be the best way to achieve it. Any ideas? Thanks.

Doug
as humorous as it would beArnold Zefal
Jan 11, 2004 3:16 PM
to see you hook your trainer up to a washing machine motor or something, I would say just train on a geared bike. ride flats and downhills way undergeared to achieve the cadence you're after for long periods. safer than doing it fixed in case you have to bail out, and should be just as effective.
yes it is another whacky ideawitcomb
Jan 12, 2004 5:02 AM
I'd love to see someone to in the their LBS and ask for a trainer with a motor, but ...

I question how much this would actually help. Would you not be better off trying to spin with a far higher gear ratio on a flat. The only difference between spinning downhill and on a flat at 130-140rpm is the effort. So, if you try to reduce the effort as much as possible, although it won't be the same, it might be close enough.
but, but, but...DougSloan
Jan 12, 2004 7:45 AM
Spinning under power isn't quite the same as descending and *resisting* the pedals, or at least getting the legs out of the way to allow the bike to "coast" down the hills as fast as possible. Biomechanically, spinning under power fast and descending fast on the fixed feel very different to me, even if they do have some aspects in common.

I'm finding that this is certainly a trainable skill. The more you descend on the fixed gear, the easier it gets. Problem is, you darn near need to destroy your legs getting up the mountains to get 20 minutes of descending. And, there is no way to simulate this at home.

So, the question isn't so much *whether* or *why* to do this, but *how?*. To whacky to even attempt?

Doug
ok then, how about thiswitcomb
Jan 12, 2004 8:18 AM
Have two sets of rollers, set side by side. Now, you link the two (or just one) rear rollers of each set somehow. Now, have a friend ride forward with a nice big gear and you try to slow him down with a tiny gear. I have a feeling that could turn in to some interesting riding, especially if the rollers are are set arms length apart.

Also, I saw that Keitler has a headwind fan. It basically links up to the front roller on a mount. The mounting would be identical to what you would want for an electric motor. You might want to check out that design. Attaching a DC Motor (~500 Watt) in place of the fan should be striaght forward. I'm not saying that you should buy the Keitler fan just for the mount, just check out the design.

Post images of your final solution, it would be comical.
Since we're being wacky, rollers with a treadmill motor?dzrider
Jan 12, 2004 7:55 AM
You could engage the motor from opposite sides of the gear to provide either resistance or acceleration.
why not just switch to an 18t cog?cmgauch
Jan 12, 2004 7:56 AM
Or you could do downhill hill repeats & get someone to drive you up the mtn.

I know: use rollers but put somebody on a moped facing the other way with that rear wheel next to your bike's. Try to keep up as they twist the throttle. Insert picture of G. Jetson here: "Jane...stop this crazy thing!"

PS - how was it climbing the 4,000 ft mtn?
George JetsonDougSloan
Jan 12, 2004 8:42 AM
Yes, that image has occured to me. It would definitely need a "dead man" switch!

Climbing is hard. Darn near need to stand the whole time. I focus on saving my knees, so I raise up my hips and straighten the knees first, then push down. Of course, that causes other issues, but really helps the knees.

Heart monitors are superfluous. You pretty much "do what you can do," and there's little discretion to go harder or easier.

At one point my speed dipped under 6 mph on a 12% section around 3,000 feet. That's around 30 rpms. Couldn't handle much of that.

The Kreitler wind attachment is a good idea, but I might just fabricate something and then buy their belt.

I think I'll wear my helmet the first time I try this...

Doug
Shuttle...rcmann
Jan 12, 2004 8:54 AM
You can always do what downhill MTBers do and shuttle to the top of a mountain then ride down. That would have top be one of the stranger things I've ever heard of, though. Rod
nice climbcmgauch
Jan 12, 2004 9:31 AM
The big hills around here (northern NJ) are pretty much all under 1mi with a few that are just a bit longer. The lowest rpms I've seen was 12, but my rpms dip into the 20s regularly. I try to think about my arms when suffering up climbs.

Decending those same hills only takes 1-3 minutes so I don't really have a frame of reference for extended high rpm (~150) riding.

It seems the most practical to do downhill repeats if you can get a ride to the top each time. This is all training for the Furnace Creek? Very admirable - especially on a FG.
climbs around hereDougSloan
Jan 12, 2004 9:43 AM
The mountains near here offer nearly unlimited climbing potential, up to 9,300 feet elevation from nearly sea level, if you don't mind a 130 mile ride. This 4,000 foot climb was actually much higher, but I turned around before the top.

Yes, this is both training and testing potential for FC508 fixed. I think that in addition to training for this bugger, you have to find the right compromise gearing for climbing and descending. With 35,000 feet of climbing, and descending, in that event, and some hills over 20 miles long, you gotta figure this out. So much for simplicity of fixed...

My theory is to use the tallest gear I can, but still allow me to climb all the hills, ranging up to 15% in places, and over 20 miles long, even a bit bonked or fatigued, and then train myself to spin my @ss off on the descents. I figure that too tall of gears could knock me out of the race, but too low is merely a hindrance on the descents. You can *always* go downhill, albeit more slowly.

The hill repeats make sense, but it's just too inconvenient to have someone take me up, and repeatedly climbing to practice the descents... well, let's just say I don't have the legs for that, yet.

The hills around here may be steeper, but not as long as the FC508 course. I figure that some descents on the course may require spinning at 25-30 mph, or 125-150 rpms, for well over an hour at a time! I don't want to experience this for the first time during the event, thus, the gizmo needed to practice/test this.

Doug
That's seriouscmgauch
Jan 12, 2004 10:49 AM
As cyclists we are used to doing things non-cyclists find amazing because they can't imagine what it's like (climb a certain hill, ride __# of miles, descend at 50 mph, etc.).

I find the FC508 amazing in much the same way. You have a big pair to go for it - brass ones to do it fixed. Godspeed.

PS - my last idea on the trainer thing: How about installing a bike-mounted motor on your fixie?

http://www.jmbpowerproducts.com/
1500 watts of gravity!DougSloan
Jan 12, 2004 11:26 AM
Now that's thinking. I'll just get on the trainer and hook up 2 horsepower to the rear wheel, then try to keep up. Sounds absolutely nutty, but that may be ideal, actually. Throttleable, simple, even if noisy.

Let's see, 2 horsepower = about 1500 watts; 1500 watts is like descending at 47 mph (according to analyticcycling.com) Cool.

Thanks.

Doug
@ 20 rpms can we say the "W" word? nmdzrider
Jan 12, 2004 11:50 AM
what's that? nmDougSloan
Jan 12, 2004 11:56 AM
walk. nmdzrider
Jan 14, 2004 1:54 PM
never! nmDougSloan
Jan 15, 2004 8:30 AM
Only after I fall over, and it hasn't happened yet (nm)cmgauch
Jan 15, 2004 11:41 AM
re: another whacky ideaukiahb
Jan 12, 2004 11:46 AM
hmmm...thats not so wacky...actually, if a trainer were built with the right sort of DC motor it could also fuction as a generator (connected to a electrically resistive load)to provide variable resistance also....maybe make the controller progammable??....then you could simulate any kind of fixed gear ride. A similar motor/generator setup is used to provide regenerative braking for electric cars...
A Little late, but..............Len J
Jan 16, 2004 8:12 AM
why not just motopace?

It would force you to extended periods of high cadence work at a fixed speed as well as put you in a position where you would have to back of & slow the bike down somewhat.

The only otther thing I can think of is either:

Ride on a treadmill
or find a longer more gradual hill and do repeats on it. or
a small bike moter that spins the wheel faster.

Good luck.

Len