AnthonyG

Sigh!
Bike shops and manufacturers know NOTHING about bike geometry either, yet someone is here shilling for them none the less.
Sigh.

I've been trying (and succeeding up to now) to NOT offer my own advice on this, yet here I go.
The cranks you are using, and have been specified for the bike, are too long for you. You have long legs so long cranks seem right, yet your short femurs and long cranks have led directly to the steep seat tube angle to be specified in order to find KOPS.

There is not a bike shop or bike manufacturer in the World that would not have made the same mistake.
If shorter cranks were specified and fitted ( I don't know off the top of my head. Maybe 165mm) then the seat tube angle required for KOPS would be more like 73 degrees.
The fact that such a steep seat tube angle was specified to find KOPS is an absolute alarm bell that something was amiss, but no one was going to see this.

guy153

If you're stopping at a junction or have to wait for a bit then it's quite convenient to be able to just stand with both feet flat on the ground. Not a huge thing but there's no good reason not to have this feature.

AnthonyG

Standing with BOTH feet on the ground over a bicycle, while waiting for traffic, is something that I have never, ever, ever, ever done.
One foot clipped in always.
You can do things you're way if you want, I just don't understand why everyone comes here telling us that their way of doing things is the only way.
By all means buy bikes with standover clearance for yourself.
I'm objecting to the notion that standover clearance is the most important aspect of bike fit, and the thing is, this whole notion of "standover clearance" came to prominence because the Industry made it happen by telling the shops that this was how it had to be from now on.

Iride01 

Peoples still don't understand that their criteria for choosing a bike isn't necessarily a valid concern for a bike fitting one properly to ride.

Given a bike that will fit me properly and make me the fastest cyclist on the planet but has a high top tube that might rack me, I'll take that chance any day and go with that bike.

Fit isn't completely about comfort! Especially when stopped.

PeteHski

Any mention of KOPS at all would be an immediate alarm bell for me. As would a 76 degree STA on a touring road bike.

oldbobcat

What do you mean by "off-road touring bike?" A profile image of what this bike should look like, and how you are supposed to sit on it, would be most helpful. Is it to be used with drop, flat, or riser bars? Will it be used for carrying loads, and if so how are they to be positioned on the bike?

I mean, my image of an off-road touring bike would be what is now marketed as a gravel racer with racks, but what do I know?

oldbobcat

Lack of standover clearance limits the rider's ability to get their landing gear down in an emergency. Unless the rider has super-stubby legs, lack of standover clearance is an indicator of other fit problems.

And personally, this retro-grouch can straddle his handlebar stem (not too comfortably, but . . .)

Even though a 76 degree seat tube sounds suspicious, I'd like to see a photo of this bike before passing judgement on it. Even better, a photo with the rider on it.

Iride01 

I feel your argument doesn't have a leg to stand on because most all cyclist have a leg to stand on! <grin>

Maybe it's because I've for a long time rode oversize bikes, but typically at stops, when they are short stops, I only stop and stand on one leg with the other on the pedal. I can lean the bike as much or as little as is comfortable for me at the time and stand over is not a problem or issue.

.I still can't imaging that either. Even a large Specialized Shiv, which is a time trial bike only has a seat tube angle of 75.75°. So coupled with the OP's words I'm having a lot of trouble picturing what an off road touring bike is. Touring to me means long times in the saddle and grinding away on the pedals. Something that I'd think not comfortable with a high seat tube angle.

Perhaps if the OP was 195 cm instead of 185 cm the STA would make more sense.

oldbobcat

Most builders slacken the seat tube as the the rider's height increases, although that might have more to do with trying to keep the wheelbase short while lengthening the top tube. I'm 182 cm tall, and after I retired my Raleigh Super Course all of my seat tubes have been in the 72-73.5 degree range. I favor 72.5-73.

As for the OP's custom gravel tourer, it must be either some sort of full-suspension hybrid optimized for hillclimbs or it rides like a jackhammer to the perineum.

And now I understand about short riders. With that I leave a photo of the world's most successful (and prettiest) rider to ride bikes that were too big, Eileen Sheridan.


And here's a photo of somebody we all know and love, who could put either or both feet down, providing he loosened his toestraps first. I think his wife and sons are wishing him a productive day at the office.

oldbobcat

This is totally weird.125 mm head tube giving you 601 mm of stack?

I'm comparing these numbers with the Trek Checkpoint ALR geometry chart. Your reach is shorter than a 49 cm Checkpoint. Your stack is like a 58. A photo of this thing would answer a lot of questions. You don't even have to sit on it. You are just a slightly long-legged 6'-1", kind of a larger version of me. Unless your arms are really short.

icemilkcoffee 

If your knee is over the pedal spindle then you are roughly correct in your seating position. Why do you think you are still too far forward?

Iride01 

Yes they do. And I've never quite understood that. As your saddle height increases you are already moving the saddle back further from the vertical datum of the BB. So making the seat tube angle slacker for a taller person seems a double whammy putting them ever further behind the vertical BB datum. But as my luck would have it, I'm 5' 11" (180 cm) and most bikes seem tailored to my height! All other sizes are derivative of that standard size adult.

I suppose they are trying to stay in KOP's. But I'm not a believer in KOP's as I see nothing important to the knee position when the cranks are horizontal. Though I do see it as sometimes useful for guess where ones saddle might should be put to start out finding where it wants to be.

Or the other thing is on frames getting smaller than say about 54 cm, the seat tube would rub the wheel if they didn't increase the seat tube angle. They could increase the chain stay length, but the increased wheel base might make it look odd.

AnthonyG

This little quirk of slacker seat tube angles for longer legs happens because of the fact that crank lengths don't often get longer after 175mm, yet there is the odd exception.
As the crank length gets relatively shorter, you need to push the seat further back to maintain KOPS.

This is the flip side of the coin where small frames with relatively long cranks have steep seat tube angles in order to find KOPS.

EDIT: At this point a light bulb should go on in your head as you realise that the standard range of crank length from 165-175mm is clearly and demonstrably, "inadequate", yet most won't get it.
The Industry DELIBERATELY resists the obvious truth. The "bean counters" shut everyone up and enforce their silence.

Iride01 

IMO, KOPS has been shown to be a myth many times since it's inception.

And I'm not sure I blame industry as much as I do the many vocal consumers that still believe the dogma of KOP's and many other things about bike fit. Industry might just not be willing to take on the challenge of all the negative their weight would bring to bear on them.

oldbobcat

Cervelo uses a 73 degree seat tube angle for all sizes and adjusts the head angle for top tube length. They also adjust fork offsets for head tube angle so that within a model range, all trail figures are identical. If the opportunity presents itself, my next bike will be a Cervelo Soloist or R4.

It used to be that a builder's "ideal" was a "square" frame in a medium size.That meant, at 54-55 cm, the top and seat tubes were of equal length and the head and seat angles would be parallel. In smaller sizes the top tube go relatively longer, and in larger sizes it got relatively shorter. Seat tube and head angles were adjusted to implement this. When you were building in butted steel, keeping the tubes short was fundamental to maintaining handling and acceleration. At 54 cm a Peugeot PX-10 could be delightful, but over 59 cm they got rather whippy. Which is why Eddy eventually rode a Masi in Peugeot livery in 1967.

As for crank length and KOPS, I don't see the relationship. Crank length and heel position, heel position in relation to knee position, yes, but people with longer legs also have bigger feet, and we're usually talking about a centimeter or less in either direction. The range of crank length is much less than the range of rider leg length. KOPS is BS anyway.

It seems easier to build a small frame with a steeper seat angle, especially when you're trying to keep the top tube horizontal. In some cases they even raised the bottom bracket to keep the seat lug level with the top head lug. With sloping top tubes, however, that becomes moot. Another interesting problem that slackening seat angles in larger sizes presents is the position of the riders hips in relation to the rear axle. As the rider gets taller his butt gets closer to being directly over the rear axle. Of course, with a steeper head angle and longer stem, the front end of his center of gravity is getting closer to the front axle too.

Don't blame the bean-counters. Boutique builders of lugged steel frames, who managed their finances in cigar boxes, have been following these rules of thumb since the 1960s.