This wasn't actually during commuting (still trying to find a good time to do my first partial bike commute ), but it was during practicing with my new mirror on the MUP, so I'll stick it here.

Actually, it's happened on all of my rides, but I first connected the dots now.

Basically, if it's anything other than a short ride (<2 mi or so), with downhills... if I get going quickly on those downhills, my legs start shaking horribly when I coast (which is when I'd like to stop to keep the lactate burn from getting bad.)

At first, I thought it was something wrong with my bike, because it seemed to go away as I slowed down. The tires were dryrotted, after all.

Replaced the tires, and did a ride today. The shaking was still there. One time, I came to a stop, and was still balanced on my bike... and the shaking was still there when I came to a complete stop, which tells me it wasn't the bike, it's ME. Also, after the ride, my legs felt like jello. (And it wasn't even a long ride...)

It seems to be better if I coast with one leg all the way down and one all the way up, but that (other than the lack of shaking) seems to be less comfortable.

Ideas?

it sounds like you're tired.

I experience the shakes once in a long while. Fatigue, dehydration, and cooling too quickly seem to be contributing factors. You may also want to alter your riding position or take it a bit easier.

Have you been riding for a while?
If you are just starting you may just be tired, it will go away as you ride more.

2manybikes: That's reassuring - I've done about, oh, 35 miles or so total since I got the bike (between weather, as I'm trying to take it easy, and lack of time due to driving so much, lol.)

And, I hadn't ridden a bike since I was 13 or so, until I got this one.

So, good to know it's normal.

(And, I've been trying to keep properly hydrated and all... but I think I WAS thirstiest today...)

Don't worry, your endurance will build quickly if you keep doing it regularily.

Yeah, I get the leg shakes anytime I apply alot of stress to my legs. Try doing wall sits and your legs will quickly do the same thing.

The only time It happened to me was when I first started biking after a sprint...

I just started commuting (as well as riding to go just about anyplace). After a 10 mile ride where I did some balls to the wall pedaling, when I stopped and got off the bike my legs were like jello and I collapsed.

I am going a little easier now until I am in better shape

One thing that *might* be the problem, but its just a long shot guess. Is your saddle a bad fit, could it be cutting circulation off to your legs? I've had that happen when sitting in front of a workstation too long in a crappy chair.

if its just your legs then you just need to build some strength/endurance (I would get that from lifting as well)... if you feel a more systemic tremble then you probably have low blood sugar... (need carbs and some hydration).

It was just my legs. Actually, it was just the lower half of my legs, too.

It happened to me once after a 15 mile warmup ride when I was doing some sprints. It went away after 30 seconds.

Try a sports drink before and during your next few rides. Dehydration and/or low electrolytes is a good possibility.

How about talking to your doctor about this? Are you in good general health?

I get the shakes if I ride in my really tall gear on hills.

Nothing to it, it will go away

Sounds like your potassium is low. Eat some bananas or drink tomato juice.

DTs?

Sounds good!
That kind of thing goes away fairly quickly if you just keep riding. Any old kind of riding will do for now.
Enjoy your bike.

Yeah, I've been riding around the driveway whenever I could get a chance just to get SOME riding in... (thick gravel roads + 32-630 road tires = no riding on the roads)

I've noticed that my ankles shake by the end of a mountain bike ride with lots of time out of the saddle. Pretty sure it's fatigue and nothing more.

I nearly got hit today and boy were my legs shaking after that. After it happend a lady in a convertable rolled up and was like "Must be dangerous in that line (bike lane on a huge busy Chicago street). I was sure you were going to get hit!!" That god my 520 stops strong. Better than what I could say about my last road bike

Just for some data... I got a cyclocomputer today, and did about a mile of riding to test it out. It doesn't have cadence, so all of this is calculated. (Not sure if I mentioned that spinning out makes the shaking worse, which is why I'm posting this data.)

I feel most comfortable at 70-90 RPM.

100 RPM feels like pushing it, and I spin out at 110.

This shaking happens to me after very fast downhills too. No correlation with length of ride, physical condition, hydration etc. I think it's just adrenalin. Some of those downhills are pretty exciting... I have one near my house: relatively short but really steep (you build up speed really fast), traffic light at the bottom of the hill and the road turns very sharply (90 degrees basically) only a short distance after the light. First you're bombing down it wondering if you're going to make the light, and if not how you're going to stop... next you are trying to slow down as much as you need to make the turn but not more than that, cause slowing down more is boring. My legs do shake after that one.

Worst shaking for me comes after I get back into my apartment, something about lugging my Schwinn 3-speed tank, school bag, laptop and other misc. garbage I'm carrying up four flights of stairs I think.

I'm thinking fluid & electrolytes, too, with maybe a touch of hypoglycemia and adrenaline.