Giant Explore geometry issue?

[LeftyS7]

I've been riding bikes for 65 years. I got my first bike, a Raleigh three speed, when I was 12. I've had a Bianchi 12 speed road bike, a Gary Fisher Mountain Bike, a Specialized Roll Low-entry and now a Giant Explore+3.

I'd been told and read that in fitting a bike, when sitting in the saddle, with the pedal at three o'clock and the ball of your foot on the pedal, the center of one's knee should be a plumb line through the axle of the pedal. On my Giant, even with my seat all the way back, my knee is considerably forward of the pedal axle which should make pedaling less efficient. This concerns me as there is no fix for it.

Anyone else share this concern?

 

[Mtl_Biker]

I've been riding bikes for 65 years. I got my first bike, a Raleigh three speed, when I was 12. I've had a Bianchi 12 speed road bike, a Gary Fisher Mountain Bike, a Specialized Roll Low-entry and now a Giant Explore+3.

I'd been told and read that in fitting a bike, when sitting in the saddle, with the pedal at three o'clock and the ball of your foot on the pedal, the center of one's knee should be a plumb line through the axle of the pedal. On my Giant, even with my seat all the way back, my knee is considerably forward of the pedal axle which should make pedaling less efficient. This concerns me as there is no fix for it.

Anyone else share this concern?

I have also been riding bikes for a long time... not quite as long as you but more than half a century. I've never heard that before. What I've always heard and believed, was that with the pedal down and parallel to the down tube of the bike, your leg should be almost fully extended, but not so that the knee would be locked. You've got to keep a little bend in the knee. And adjusting for that is done by changing the height of the seat.

I don't know how bad your situation is... do you find it uncomfortable? You say there's no fix for that, but yes there is... You can get an offset seat post which would move your seat back. But then you also need to pay attention to the reach of your handlebars... for that I've always believed that you put your elbow against the point of the seat and your finger tips should just be reaching the handlebars.

Could it be that your bike simply doesn't fit you right?

I had a problem with that myself... I test rode an Explore E+ with medium frame and while I could ride it alright, I found it too high off the ground. So I ended up ordering one with a small frame, without having tried it first. (It was the last 2019 Explore E+1 with small frame in all of Canada and I ordered it from clear across the country and had it shipped to me.) The height of the bike was much more comfortable for me but I hadn't realized that everything would be different on the small and not just the height off the ground. I ended up having to change my handlebar stem to get the handlebars further away AND having to get an offset seat post to move the seat back. Then the bike became much better for me but not perfect. The lesson I learned was to never buy another bike without actually having tried the model and size I wanted.

Good luck!

 

[LeftyS7]

Yes that is how to determine seat height, one of the other parameters of bike fitting. An off set seat post is a solution but I'm using a sprung seat post and there are no offset sprung posts. I've ridden my wife's small frame Liv and the problem still exists. I think a larger frame would make it worse.

Thanks for responding.

 

[percymon]

After recently watching several youtube videos on set ups it does appear these days that the knee to pedal axle line is almost the second thing they set after the seat height. The line from the knee doesn't have to be on the pedal axle, it can be slightly forward of it, so don't fret for the sake of 5-10mm Only then is reach adjusted by fitting different stem lengths (which rather makes a mockery of the fact bikes come with a standard stem, and rarely is there an option to change it free of charge). Of course at this stage you might find that the frame size isn't ideal so start again on a different sized frame !. Perhaps its more critical for drop bar road bike efficiency than for a MTB - i've never worried too much about it until this month !

 

[Stefan Mikes]

After recently watching several youtube videos on set ups it does appear these days that the knee to pedal axle line is almost the second thing they set after the seat height. Only then is reach adjusted by fitting different stem lengths (which rather makes a mockery of the fact bikes come with a standard stem, and rarely is there an option to change it free of charge. Of course at this stage you might find that the frame size isn't ideal so start again on a different sized frame !. Perhaps its more critical for drop bar road bike efficiency than for a MTB - i've never worried too much about it until this month !

You can always add a standard stem riser.

 

[LeftyS7]

I have a stem riser, which doesn't affect the seat lay-back, and am getting sweep handle bars so I can ride Dutch-style.