Frame Geometry vs. Handling Characteristics
#51
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#52
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A few weeks ago I test rode a very nice cargo bike. Front steering was with a linkage.
That thing was just all over the road. I just couldn't get it to track straight.
It felt like the wheel turned faster than the bars. And, it may have, I'm not sure. However, I finally determined that the issue was the thing had these big Texas Longhorn handlebars. And, for me, it is extremely rare to ride a bike that doesn't have drop bars. So, I've likely trained my muscles for drop bars.
So, with these longhorn bars... And a light load, I think I was just over-steering really badly. I've finally realized that I was probably getting too much leverage with the bars (for my riding).
I've started switching bikes & loads a bit on my own bikes. Within a hundred or so miles, I do get used to whatever bike I'm riding. And, I suppose returning to that bike is easier than the first time out.
That thing was just all over the road. I just couldn't get it to track straight.
It felt like the wheel turned faster than the bars. And, it may have, I'm not sure. However, I finally determined that the issue was the thing had these big Texas Longhorn handlebars. And, for me, it is extremely rare to ride a bike that doesn't have drop bars. So, I've likely trained my muscles for drop bars.
So, with these longhorn bars... And a light load, I think I was just over-steering really badly. I've finally realized that I was probably getting too much leverage with the bars (for my riding).
I've started switching bikes & loads a bit on my own bikes. Within a hundred or so miles, I do get used to whatever bike I'm riding. And, I suppose returning to that bike is easier than the first time out.
#53
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Same here. And we're all sounding like experienced cyclists who have tried many bikes, and that's because we are. Weirdly, when I try a new bike, often the cranks feel like they're bent to me. The worst one was the Bianchi Volpe I had for a while. I don't know why. Maybe the Q factor was bigger. But eventually, that illusion went away.
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#54
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Same here. And we're all sounding like experienced cyclists who have tried many bikes, and that's because we are. Weirdly, when I try a new bike, often the cranks feel like they're bent to me. The worst one was the Bianchi Volpe I had for a while. I don't know why. Maybe the Q factor was bigger. But eventually, that illusion went away.
OK but it's worth mention that this yellow bike - the cranks have never felt funny. But the other two bikes I pictured here, yes, cranks felt bent. My old 3 speed - nope. I had an old MTB I gave my brother - nope. My old Schwinn Super Sport I sold - nope.
#55
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That triangle goes out the window when my butt comes off the saddle. That's the point. I need to move my hands around the handlebar so I don't settle into one position, and I need to get my butt off the saddle occasionally to restore circulation .a hill climb is the perfect excuse for that, but I have to do it now and then whether the hills or not.
#56
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A very nice explanation of bike geometry here:
https://en.wikipedia.org/wiki/Bicycl...cycle_geometry
The discussion on wheel flop and weight distribution changes is very on point.
https://en.wikipedia.org/wiki/Bicycl...cycle_geometry
The discussion on wheel flop and weight distribution changes is very on point.
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I don't have the scientific data to back these notions up, but my rudimentary familiarity with cycling and physics will leave me convinced until data from a properly constructed experiment can persuade me otherwise. I think Newton would be pleased with me.
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#60
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Perhaps it should be pointed out that if by handling, we are talking about descending on twisty roads, then the CG is going to be all over the place. At least it will be if you are going fast and using good technique. Butt should be out of the saddle slightly. Shift weight rearward as you approach the apex of a turn, to maximize stopping power. Bike should be rocking beneath you; your legs and arms are the suspension. Weight may shift forward again if you jump out of the corner.
Perhaps a bit OT but I'm often shocked by the poor descending/handling skills I see these days. This is stuff that used to be learnt from other more experienced riders in your club/team.
Perhaps a bit OT but I'm often shocked by the poor descending/handling skills I see these days. This is stuff that used to be learnt from other more experienced riders in your club/team.
Last edited by Salamandrine; 10-24-18 at 12:11 PM.
#61
Virgo
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There is a difference in the way my two current bikes (72/71 and 73/73) track when riding out of saddle, you know, the bike is rocking left to right a little. They don't behave the same, but I can't quantify the difference at the moment. I'll have to pay attention to 73/73 on my ride home and take 72/71 for a spin this evening to check it out and report back.
And again - man, this discussion is great. Thank you all again so much.
And again - man, this discussion is great. Thank you all again so much.
#62
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I've read a lot on the discussion, and I feel I still don't have a handle on all the parameters and how they make a bike feel. It's very interesting anyway.
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#63
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To make comparisons you start by being accurate. I was about to say 650mm front center is beyond believable. Looking again at the photo maybe that yellow bike is that long. But if it is, and has the chainstays too we're headed for 43" of wheelbase. Wow. Both bikes are just really long.
Some measurements come out same reliably and other like front center and fork rake consistently produce odd numbers you have to check and check again.
Some measurements come out same reliably and other like front center and fork rake consistently produce odd numbers you have to check and check again.
#64
Virgo
Thread Starter
Ok, so 72/71 takes more effort to start the turn, like a combination of leaning and pushing on the bars, and unless I hold a little pressure on the bar, it wants to come OUT of the turn. If anybody else has ever flown an airplane, it’s a little like having to hold a little rudder through a banking turn, some planes will stay in a coordinated turn and others need a little attention. The 73/73 takes a light touch but mostly just leaning, it enters the turn more quickly and the “tightness” of the turn is controlled mostly by how I shift my weight, my hands don’t do really anything but keep the bars from jumping if I hit a bump or something. It stays turning until I right it.
Out of saddle on 72/71 is weird. I already said this, but rocking side to side is different. It’s harder to do it, like I have to put some effort into sort of turning the bars, whereas on 73/73 I can sort of just throw them back and forth, like dribbling a basketball almost. 72/71 just doesn’t do that, I have to keep a firm grip.
Another difference I noticed both seated and out of saddle is that 72/71 handles differently depending on speed, it sort of gets easier and more predictable the faster the bike is moving. 73/73 to me pretty much feels and handles the same at 10mph as at 20. Very predictable.
Out of saddle on 72/71 is weird. I already said this, but rocking side to side is different. It’s harder to do it, like I have to put some effort into sort of turning the bars, whereas on 73/73 I can sort of just throw them back and forth, like dribbling a basketball almost. 72/71 just doesn’t do that, I have to keep a firm grip.
Another difference I noticed both seated and out of saddle is that 72/71 handles differently depending on speed, it sort of gets easier and more predictable the faster the bike is moving. 73/73 to me pretty much feels and handles the same at 10mph as at 20. Very predictable.
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OK so if frame angles are what determine the difference, then your preference is for the steeper angles. But I'll bet you don't have anywhere close to identical bikes.
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#66
Virgo
Thread Starter
Angles aside, I like the predictability of the handling of 73/73 while commuting. I place a high value on not having to dedicate a lot of attention to handling the bike. It’s nice that it’s easy and intuitive enough that it pretty much just goes where I want it to without any fuss at whatever speed.
There is probably some context where the 72/71 would perform nicely, but there’s just not enough variety in my riding to figure it out.
Someone a while back in this thread I think nodded to off road or cyclocross geometry. I have no appetite for either of those things, at least at this point in time.
Before I ultimately decide whether or not to give 72/71 the old heave ho, I might try a shorter stem just to see what happens. If it tightens up the handling enough, I may keep it around. It’d be a super candidate for a SS/FG conversion.
#67
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I wonder if a longer stem on the 71/72 might be more in order. My Rivendell Clem is little unruly out of the saddle when I'm on the main grips on Albatross bars. If I climb with my hands in front of the brake levers, it's much more like my road bikes. The HTA is 71.5. Might be worth experimenting with longer and shorter stems.
The general steering differences described are typical.
The general steering differences described are typical.
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Try the shorter stem, even if it's just 1/2" shorter (British stems are spec'd in inches).
And use a slightly wider bar as well, which in my experience alleviates some of the out-of-saddle steering heave if the stem is still marginally too long for the headtube angle.
My 23" 1973 SuperCourse handles well with a 4-1/2" stem, forward saddle and 42cm handlebars. Good both in and out of the saddle, spirited club riding in the foothills.
No, it's not as lively as bikes with lighter weight, shorter wheelbase and steeper angles, but it handles well with no real issues other than my needing to exert some counter-steering effort to hold the inside line in heavy cornering situations.
And use a slightly wider bar as well, which in my experience alleviates some of the out-of-saddle steering heave if the stem is still marginally too long for the headtube angle.
My 23" 1973 SuperCourse handles well with a 4-1/2" stem, forward saddle and 42cm handlebars. Good both in and out of the saddle, spirited club riding in the foothills.
No, it's not as lively as bikes with lighter weight, shorter wheelbase and steeper angles, but it handles well with no real issues other than my needing to exert some counter-steering effort to hold the inside line in heavy cornering situations.
#69
Virgo
Thread Starter
I wonder if a longer stem on the 71/72 might be more in order. My Rivendell Clem is little unruly out of the saddle when I'm on the main grips on Albatross bars. If I climb with my hands in front of the brake levers, it's much more like my road bikes. The HTA is 71.5. Might be worth experimenting with longer and shorter stems.
The general steering differences described are typical.
The general steering differences described are typical.
Do you mean general steering differences are typical for the frame angles or ... ?
#70
Virgo
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Try the shorter stem, even if it's just 1/2" shorter (British stems are spec'd in inches).
And use a slightly wider bar as well, which in my experience alleviates some of the out-of-saddle steering heave if the stem is still marginally too long for the headtube angle.
My 23" 1973 SuperCourse handles well with a 4-1/2" stem, forward saddle and 42cm handlebars. Good both in and out of the saddle, spirited club riding in the foothills.
No, it's not as lively as bikes with lighter weight, shorter wheelbase and steeper angles, but it handles well with no real issues other than my needing to exert some counter-steering effort to hold the inside line in heavy cornering situations.
And use a slightly wider bar as well, which in my experience alleviates some of the out-of-saddle steering heave if the stem is still marginally too long for the headtube angle.
My 23" 1973 SuperCourse handles well with a 4-1/2" stem, forward saddle and 42cm handlebars. Good both in and out of the saddle, spirited club riding in the foothills.
No, it's not as lively as bikes with lighter weight, shorter wheelbase and steeper angles, but it handles well with no real issues other than my needing to exert some counter-steering effort to hold the inside line in heavy cornering situations.
Edit: also, your Super Course is delicious.
Edit 2: current bar is 42, not 44. So I think I’d go 40. I’ve ridden a 38 and it was a little narrow but OK.
Last edited by Phamilton; 10-24-18 at 05:24 PM.
#71
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I think the BB to handlebar position is where you feel it the most when riding out of the saddle. That takes more time for the body to adjust, but it does adjust.
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I try to get the same triangle, its corners being the seat, handlebar, and crank, on every bike. But the base of that triangle is the relationship between saddle and bottom bracket. Those two will have the same relative position as long as I'm on the saddle. Meanwhile, my hands will move around to different parts of the bar, so the position of the bar, and even it's shape, can vary.
That triangle goes out the window when my butt comes off the saddle. That's the point. I need to move my hands around the handlebar so I don't settle into one position, and I need to get my butt off the saddle occasionally to restore circulation .a hill climb is the perfect excuse for that, but I have to do it now and then whether the hills or not.
I can't say I pay much attention tot where the wheels fall, in relation to that triangle, I know it's important; that may even be the thing that defines the different between the two bikes I mentioned before; but I haven't managed to get control of it, even in theory.
That triangle goes out the window when my butt comes off the saddle. That's the point. I need to move my hands around the handlebar so I don't settle into one position, and I need to get my butt off the saddle occasionally to restore circulation .a hill climb is the perfect excuse for that, but I have to do it now and then whether the hills or not.
I can't say I pay much attention tot where the wheels fall, in relation to that triangle, I know it's important; that may even be the thing that defines the different between the two bikes I mentioned before; but I haven't managed to get control of it, even in theory.
And you are unable to keep your hands in one place when out of the saddle? How long of a stretch do you ride out of the saddle?
#73
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Yes, I think I do move around on the saddle; but I don't think I do that very much. At any rate i probably do most of pedaling from the same position, so I try to have the saddle in the most efficient location relative to the pedals. I assume if every bike has the saddle is in the same position relative to the pedals, I'll have the same range of motion around the saddle on each bike.
And I can't estimate how much time I spend out of the saddle. A year ago I would have said "almost none," but I'm learning the benefits of getting out of the saddle and am trying to make a habit of it. Last Saturday I did a ride on my old Fuji Finest on which I was forced to climb out of the saddle for a couple long stretches. It was hard work. Dunno, five or ten minutes? I'll see if I can figure it out from Strava, it's an interesting question.
At the end of May I did a grand brevet around the DC area and after four days my butt was very tender indeed. But on more recent rides I haven't had that problem; the main difference being a conscious effort to get out of the saddle.
With that, I've raised my lowest gear; having a very low gear allows me to sit and spin, but not having such a low gear forces me to stand up more.
As for my hands, I get wicked carpal tunnel pain if I don't move hands around a lot. I don't want there to be any especially comfortable hand position, because that would make me lazy. Hence no brifters for me....
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In lieu of switching to an 8cm stem, perhaps first try riding off of the saddle with hands in different locations on the bars and lever hoods. This should clarify which direction that you might want to go with stem length, and if the steering "heaves" with hands in all three positions then I would investigate whether the headset is turning with zero resistance about center (holding bike off the ground and nudging the bars slowly with one finger).
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Different Angles, Different Ride
My favorite ride seems to be the one I was just on...
all are set up very similarity. And I've not been doing high speed technical descents. What I'm finding weird on my newest build is the toe overlap. It's a 93 Serotta Legend CR, and I have rubbed my toe twice, hard, at very slow speed, once doing a uturn, and creeping forward waiting for light to change. Probably has steeper angles and fork rake, than 70s/80s Italians or Ron Cooper. Going to have to change my turning and wobble radius or end up on my side.
all are set up very similarity. And I've not been doing high speed technical descents. What I'm finding weird on my newest build is the toe overlap. It's a 93 Serotta Legend CR, and I have rubbed my toe twice, hard, at very slow speed, once doing a uturn, and creeping forward waiting for light to change. Probably has steeper angles and fork rake, than 70s/80s Italians or Ron Cooper. Going to have to change my turning and wobble radius or end up on my side.