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Position(8 posts)

Feb 6, 2002 4:05 PM
I am setting up a new/used road bike with the intent of racing again. Are there any rules of thumb as to how much seatpoast should be exposed. And why? A typical 5'10 male with 31" inseam. What would be the optimum set up for him/me?

re: Positiondownunderracer
Feb 6, 2002 5:50 PM
Not so much that the seat falls off the bike. ;-)

Seriously, you want to be able to sit comfortably on the seat so that when your leg is straight and the crank is down and in line with the seat tube, there is a gap of a few millimeters between your the heel of your shoes and the pedal. You may need an assistant or a stand to hold your bike while you maintain a balanced position on the seat. When your foot is engaged with the pedal, you should be able to straighten your leg so that your foot is 15 to 20 degrees from the horizontal with your heel down without lifting yourself off the seat.

You will know if the seat is too high if your pelvis rocks from side to side when you ride. If it is too low, you will tend to get sore knees. When you start off, you may want to err on the side of too low, and then raise the seat by small increments over time as your muscles and tendons get used to the additional stretching.

If you want to get even more accurate, you have to adjust your seat height to your pedalling style. If you ride with your heels down, you want your seat to be relatively lower than it would be if you tend to point your toes down.

Happy racing,
Good adviceallervite
Feb 7, 2002 2:29 PM
I like a little lower position with a bit of setback myself. There is no hard rule on how much seat post should show. Different style frames for the same size rider will show more or less seat post. Here are some generalizations:

The lower your seat: The faster you can spin your pedals, the more likely you are to hurt the back of your knees, the more you will use the back of your legs.

The more setback your seat: the more you will use the back of your legs and glutes, the more leverage you will have to push the pedals.

The higher your seat: The more leverage you will have to push the pedals, the more likely you are to hurt the front of your knees.

The more forward your seat: The faster you can spin your pedals, the more you will use your quadriceps.

A lot of road racers like a low setback position. A lot of time trialers like a high forward position.

Crit riders fall somewhere in between.

But everybody is different.
Good adviceWannabe
Feb 8, 2002 7:33 AM
Here's my dilema, I've got one bike that seems to be dialed in. It was my regular bike until this past late summer when I got a new bike after many years. The problem is that I can't seem to get the saddle height set yet. I was thinking that the saddle was still a bit too high as I am getting pain in the back of one of my knees, but judging from your post this would seem to indicate that my saddle is too low? The small incremental changes I have made so far (making the saddle lower) would seem to indicate the opposite as at first I had pain in the back of both knees and I have slightly lowered the saddle, which has alleviated the problem in one knee and improved a bit in the other.

I know I know, I need to get to my shop to have them fit me. And I will. Fortunately I have my old bike for a reference. But the post raised a question that I wanted to ask:

Pain in the back of the knee: saddle too low? (really?)
Pain in the front of the knee: saddle too high?


Andy - Wannabe
Good advicebrider
Feb 8, 2002 9:43 AM
Actually, I think allervite got this one backwards. If the saddle is too low, that's going to strain the hamstring tendons at the back of the knee. If it's too low, it's going to contribute to knee-cap mistracking at the highest loads. However, he was spot on with the fore-aft statements.
Feb 8, 2002 10:17 AM
Just generalizing as I said above. Too low a saddle can cause an injury to the front of the the knee and vice versa. However, lowering a saddle too much after being used to a high saddle will often cause pain in the back of the knee because your hamstrings are pulling on those tendons back there much harder than they are used to.

I don't think this is the case with this Post though. I would suspect that his new frame has a more slack geometry which is causing his seat to be set back further than he is used to. Just a guess though.
Good adviceWannabe
Feb 8, 2002 11:24 AM
"If the saddle is too low, that's going to strain the hamstring tendons at the back of the knee."

You mean too high I think. Yes, this makes more sense.

Andy - Wannabe
re: Positionbrider
Feb 7, 2002 2:00 PM
Seat post showing is irrelevant. With your inseam, you're going to wat a 55-56 cm frame size. The seatpost will take care of itself. You're going to want the seat high enough that you get good extension of the leg (not straight, but slightly bent at the bottom of the pedal stroke), but not so high that your hips rock. Another important measure is the reach to the handlebars. If you're buying new, have the shop set you up for a good position. They should be able to swap out stem sizes for you at minimal charge. If you're buying used, you may be at the mercy of the equipment on the bike. If the fit isn't quite right, make sure you factor in things like a new stem or handlebar into your financial considerations.