sysrq

1. Cheap aluminium alloy Mercurio road bike frame converted to touring bike with Suntour NCX suspension seatpost, butterfly handlebars, Lepper leather saddle with mattress (cover springs) and Schwalbe Marathon Pluss 622x32 tyres inflated to 40psi pressure. Total weight about 100kg.
2. Raleigh high tensile steel 18-23 frame with telescopic suspension seat post and the same tyres and the same saddle.
3. XB3 Tourist (unknown steel frame), obsolete German leather saddle with cover springs, cafe handlebars and unknown Schwalbe 622x32 tyres inflated to 30psi. Total weight 80-100kg.

I'm trying to get used to the first example after years of being able to ride whole day without significant discomfort while using the third example.

Now thinking about using the second example.

Seems like suspension seatposts aren't doing anything to improve comfort when used with aluminium alloy frames. Might reduce frame fatigue and keep the wheels true for longer though.

bpcyclist

Don't intend to be rude, but why would these be our only options? Lots of good bikes out there, many, quite affordable. If you are going to be commuting, you really want something dependable and safe.

TheDudeIsHere

Bah! Good quality built wheels keep wheels true longer. Clydesdale here, over 20,000 miles on a set of wheels riding an aluminum roadie. Built them myself. A shock post would not make one bit of difference.

As far as choice, I would not select any bike that I could not test ride. If I could, the most comfy would be the one I would chose.

sysrq

Looking for new one in your local LBS might be cheaper, but according to personal experience one always ends up with rebuilding, customising something or returning and reselling.
As far as I know nowadays there are only available low quality hight tensile (mild) steel frames or chromoly steel frames which are made with larger diameter tubing therefore stiffer and more uncomfortable. This leaves old steel frames as the best option.

csport

FWIW, KhVZ is Kharkov Bicycle Factory, there are Wikipedia pages in Russian and Ukrainian regarding this bike: https://ru.wikipedia.org/wiki/%D0%A2...F%D0%B5%D0%B4)

Happy Feet

What a strange OP. What difference does frame material have to do with a suspension post? What the frame is made of doesn't effect the behavior of the post.

30 seconds and google lets me know the XB3 is an old Russian bike made by a company called Mecholaton.

My vote is whatever is cheapest at the thrift store.

Was the last time you looked at bikes 1973? Only low quality high tensile or chromoly steel frames you say...

Machka 

Are these the three bicycles you currently own?

And I'm guessing you haven't been bicycle shopping in a while?

sysrq

​​​​​​First one is fully assembled, second one is a frame in a need of painting, third one is long gone now. All of the brand new midrange bikes I have bought had all sorts of problems, so not exactly sure if repeating the same mistakes all over again would be the best thing to do at this point.

livedarklions

I think you're asking us which of 2 frames you'll find comfortable. I'm pretty sure none of us can tell you that.
What's wrong with your current bike? We really don't have any idea what you're trying to improve.

That pressure seems pretty low for 32s. Maybe futz around with different pressures and saddle/post choices before you start a big project. I've generally found that suspension seatposts are worse than useless.

shelbyfv

Agreed but consistent with posting history. Seems OP may be isolated in some backwater where the only bikes/components available are old junk. Probably needs a long distance escape bike!

Maelochs

I definitely cannot recommend the XB3 Tourist since it “is long gone now.” Why you would mention a bike that doesn’t exist is hard to understand.

The other two are probably very similar. The steel might be a bit less buzzy, that is, it might dampen really small, high-frequency sort of road shocks, but it depends on the shape of the fork as much as anything else.

If you have one bike built and running …. Is it uncomfortable? How is it different from the bike you used to b able to ride all day? (Also, how has your body changed?)

As for the suspension seatpost---as others have said, it has nothing to do with frame material. Frame fatigue is not really an issue---they are made of metal---and the only way it would matter with the wheels would be id you rode planted in the saddle and didn’t lift up for big bumps, or hit a big bump unexpectedly---and in neither case would a suspension seat post do very much to keep the wheel from bending or a spoke from breaking if the hit was hard enough to do that.

It seems to me, the question you need to ask is, “How can I make my bike more comfortable.”

To know that, you would need to figure out what makes it uncomfortable. Is it not the right size? Is it not set up properly (wrong relationships between saddle, bars, and pedals)? Those are what really impact comfort. Any bike will kick back impacts over bumps …. If you ride really bumpy roads all the time you are going to feel bumps. Nothing but a suspension forks will make bumps go away.

Maelochs

Also, you say "All of the brand new midrange bikes I have bought had all sorts of problems, so not exactly sure if repeating the same mistakes all over again would be the best thing to do at this point." What problems? What went wrong that those bikes did not work? Also ... what is "mid-range" to you. It could be $600, $1200, $or $2000-$3000 where I live ... which is a pretty wide range.

What bikes have you bought and what went wrong?