Gus90

So I have a few bikes, two of which were professionally fit for me. My road bike saddle is high enough from the ground that I can just barely touch the ground while still sitting on it. My most recent bike, a cyclocross, was fit such that when I'm sitting on the saddle, I literally cannot touch the ground with my toe. I realize the important part of saddle height is in relation to the pedals, but am I wrong in thinking that I should at least be able to touch the ground with my tip toe? I'm not used to always getting out of my saddle at a stop but just putting my toe down.

Am I sacrificing fit by lowering my professionally fit cyclocross bike a bit so my toe hits the ground? I'm guessing the difference is about 2 centimeters.

These pics may give a bit of reference as to how my road bike is vs the cyclocross if you look at the lines on the garage door. Although I think the road bike tires are a little further away from the door than the other. The cyclocross has not been lowered yet to were I can hit the ground. Outside of that, both feel pretty darn comfortable to ride.

rpenmanparker 

Many folks like to stay perched on the saddle and lean the bike enough to touch the ground with their toe. I think this is generally regarded as more expert. I personally find that really unstable and have always come forward off the saddle to put my foot solidly on the ground. It is more stable IMO. This also helps to get restarted as I start pedaling by lifting myrself up onto the saddle by standing on the pedal with the connected foot. Different strokes for different folks, but whenever I see someone having trouble with balance at a stop, it is because they are trying to stay on the saddle and reach the ground with the tip of their toe. Whatever one thinks about whether this is right or wrong, I believe most folks would agree it is wrong to sacrifice best bike fit in order to be able to more easily reach the ground with you buttocks on the saddle. It just isn't necessary.

fstshrk

I get off the saddle or lean the bike over. You are not supposed to be able to touch the ground with your feet when fully seated IMHO.

If you lower the seat 2 cm, I presume you may have quad issues and may be some upper back pain from the reduced reach. But then, it may work for you.

Mark the old position of the seatpost, lower and then see how it feels. I would not mess with the offset or the angle of the saddle.

Gus90

This is good advice, is it odd that one of my bikes was fit where I can reach the ground in the saddle and the other was fit where I can't? I realize the geometry of the two frames are totally different, so this may be a sort of dumb question but just curious.

redlude97

Cross bikes almost always have a higher BB. Which is why you can't reach the ground anymore

StanSeven

Right. BB height plus crank length to a lesser extent affects reaching the ground even with saddle heights adjusted for the same on two bikes.

xjustice09x

Saddle height for the cross bike could be same or slightly lower than your road bike.

I was professionally fit to my road, mountain, and cross bikes. My cross and mountain bike have around the same (within 2mm) saddle height. My road bike saddle height is about 15mm higher. If your seat height (bottom bracket to top of the seat) is the same for both bikes it might be a geometry difference. My cross and road bikes have roughly the same bottom bracket drop, but my cross bike bottom bracket will be slightly higher off the ground because I use larger tires on that bike. Some cross bikes have less bottom bracket drop (bottom bracket will be higher from the ground). That would also make it more of a stretch to reach the ground from the seated position.

I don't think I can touch the ground while seated. Maybe if I lean my bike over quite a bit, but it would be hard to get restarted from that position. I always move forward off the saddle when I come to a stop

Kopsis

Optimal saddle height is from the pedal at bottom of stroke to a reference point on the saddle. The older TCX has a really high BB (something like 55 mm drop compared to the typical 70 mm for a road bike), so your saddle will be higher above the ground by at least 1.5 cm. Bigger tires (28s?) will add a few mm. The CX bike may also have shorter cranks which will also increase saddle hight relative to ground a few more mm. Easy to see how you could be riding 2 cm or more higher.

It's not uncommon for CX racers to keep the saddle up to a cm lower than optimal road bike position, but that's because your butt doesn't stay planted for much of the CX course. Dropping your saddle 2 cm from optimal for normal riding will hurt your power (best case) and/or hurt your knees (worst case). Learn to come forward off the saddle and straddle the top tube as you stop/start.

BikeAnon

As mentioned, the cross BB is higher off the ground.

Draw a line in your pics between the wheel axles. Note that the line crosses much closer to the center of the 'cross crank, than it does to the road. A couple of CMs, I'd say.

Go out to your bikes, put the crank arms in line with your seatpost. Measure from the ground to the centerline of crank, then measure from center of pedal to top of saddle. You'll find one measurement set very different, and the other measurement set almost identical.

clausen

For course riding and technical trails I lower the saddle about 1cm and move the saddle back. This enables my toe to touch the ground at the start while in the saddle and keeping good leg extension while seated. While riding through a course your in and out of the saddle so much I find lowering the saddle gets it out of the way. When I use the bike on the roads I move the saddle closer to my regular road fit, a little different due to differences in pedals and shoes.