In your tri-bike fit article you wrote, “the imprecision of where the crotch actually is.” I’m curious as to what you mean. Are you referring to the fact that some people ride “straight up the middle” and some ride with their stuff off to one side or the other, and the fact that the measurements of these places can be quite a bit different? Just curious.
Also, I definitely agree with you that steep saddle height should be slightly higher than slack saddle height. There is .5 cm difference in saddle height between my tri and road bikes. I used to ride them the same, but using “method 3” I have found that I like my tri saddle slightly higher.
it has been my experience that this is just not as good a determiner as knee angle. there are three problems: placing the “book” (or whatever you place) further or less far up into your crotch; keeping the book’s binder parallel to the ground when measuring; and measuring to the right place on the saddle.
more than all that, though, i just find .885 to yield a saddle height not high enough, regardless of how you measure. i just don’t like the method. but this puts me in the gross minority, i know.
I think I might be tempted to rename methods 1, 2, and 3. I’d probably call them STEPS 1, 2, and 3. I’ve always used .885 as a starting point for myself or others. From there check the angles, and then ride and see how it feels. As you note, the .885 always felt too low, and the angles showed just that, even when I tried to cypher in the shoe/cleat/pedal stack in some way. Its been a while since I actually measured myself, but if I remember correctly, my final road seat height is somewhere on the order of 1 cm higher than .885. Tri-bike saddle height is .5cm more than that.
“i just find .885 to yield a saddle height not high enough,”
Dan, you’re not alone. Davis Phinney discounted the Guimard/LeMond .883 calculation. He found that .90-.91 of the inseam was a better starting point for saddle height.
True, but also look at their pedalling styles. Phinney had a very “toes down” pedalling style, Lemond tended to drop his heel more. Neither is “right” or “wrong”, just look at the palmares for each. I also tend to drop my heel, so I find that .885 works perfectly for me, this morning was spinning a 39 / 23 at 150+ rpm, no bouncing in the saddle at all. If the saddle height isn’t right, its very difficult to do that.
Like the man says, the formula is only a starting point. From there you need to figure out what works for the individual.
Dan, just curious- the question of whether inseam length is appropriate for setting saddle height not withstanding, do you think that those fit contraptions that look like a bike pump with a spring that shoots the handle up your crotch are more accurate than the book method for measuring inseam? It seems that these address all three of the problems you mention with the book method.
i haven’t used one. while i might like it, i’ve still go that other problem, which is i just don’t think it yields a tall enough saddle. and i’m not a toe pointer like phinney, or jacques anquetil. i’m a heel dropper, and i STILL have a problem with .885.
Basically, you take the metal rod with the wooden bit on it and stick it in the hole of the wooden platform, push down on it to compress it, stand on the wooden platform straddling this thing, and SLOWLY release it until it comes up to your crotch- then take the measurement. Sort of a cool little setup- I guess.
“i just don’t like the method. but this puts me in the gross minority, i know.”
I’ve adjusted tri saddles to .887 and keep .883 for road. This is just a ballpark setting. Micro-adjusting afterwards follows.
Using your suggested method it seems more difficult since it requires a recommended 155 degree knee bend. Obviously this can’t be eye balled and unless you’ve got a giant protractor or angle measuring device handy it seems that it could also have it’s potential drawbacks for getting an accurate measurement. Plus there is also the potential error factor of lining up the trochonter, knee midline and malleolus. I’d put the rider on a trainer, spin, take digital photos, print and then measure knee angle. Is this how it should be done? This is fine for a bike shop but for your average Joe setting up his own bike this could be a bit more complicated than the LeMond formula method.
You do need a goniometer to make this method work, and they are a little bit hard to find in the appropriate length. If anybody is interested in this tool, I made a few for some local bike shops a while back, and I still have the template around somewhere. These were pretty nice, acrylic construction (see-through) with etched centerline and scale.