roadbikeChris

It seems my bike has a bit of a slope from rear to front. Is this normal? I haven't noticed that anywhere else...

CliffordK

The first thing to do is to put it on a hard surface, and simply measure ground to top tube.

A back to front slope top tube is rare on bikes, other than "Funny Bikes" which would have a much more pronounced slope.

Are the tire/wheel sizes both 700c, and reasonably close in size (not 27")?

Does the black paint on the fork match the black paint on the head tube?

xiaoman1 

RC,
The bike appears to be at an angle to the rear wall, causing the appearance of the sloping tube...as mentioned best to check with a tape.
Best, Ben

noobinsf 

Yeah, looks like your front wheel is a bit farther from the wall than the rear, which could be producing the illusion. Like mentioned above, maybe your front tire is a slightly smaller width/diameter than the rear. Nothing looks out of alignment, and this bike would have had a straight top tube, not angled.

roadbikeChris

The back tire is a 1/4 taller. And it appear that accounts for the difference.

gugie 

There’s nothing sacrosanct about having a perfectly level top tube. When I rerake front forks on vintage bikes, the front end typically drops a few mm. Almost no one notices unless I point it out.

jdawginsc 

Profile of the different tire might account for a bit.

non-fixie 

Not all that unusual. Giant did it:

madpogue 

Whiskey tango, no one suggested putting a LEVEL on the top tube?

My vote is for the tire.

roadbikeChris

Visual confirmation via level. I say tire as well.

Doug Fattic 

It is not uncommon for a classic custom frame to have a top tube that is not level. I got an Italian made Masi in Milan in 1972 ($350 all Campy including the brakes). The top tube is off by a about 6mm. Others that owned Masis on the Classic Rendezvous list started to check how level their top tubes were and the range was anywhere from 3 to 9mm off.

xiaoman1 

You will need a level surface too..it looks more than a 1/4 inch to my old eyes and that combined with the nonparallel bike to wall "exaggerates" the drop.
Ben

roadbikeChris

The floor on which I had the bike when checking level, is level.

due ruote 

Speaking of level, I would suggest that the handlebar woes you mentioned on the other thread may have a lot to do with your saddle angle. I would level that out and ride some more before going nuts with the bars.

roadbikeChris

Please clarify "Level out" the seat. How is it out of whack? I did not realize that the seat was also adjustable fore and aft. How's this?

thook

too many variables have to be accounted for that level to even be an accurate representation.

madpogue 

To my eye, the horn (front) of the saddle is too low. There's plenty of room for personal preference, of course, but look, just as a f'rinstance, at @non-fixie 's pic in post # 8.

And yes, fore-aft position is a significant fit factor. You can also look for a seat post with more or less setback.

How many is "too many"? The floor? The tire profile? Tire pressure? Seismic activity? Granted, a measurement on a non-carpeted surface would be marginally better, but the OP's finding is enough to confirm that it's not an optical illusion.

thook

no need to be snarky. i've built alot of walls. so, yeah, the floor, the carpeting thickness, the tire pressure and/or actual size, actual level of foundation even. and, a small tiny level like that is very sensitive to variation compared to a longer tool. the better way to really determine would be a measuring square; top tube against the dropouts.

i'm not saying the top tube is or isn't level, btw. i'm just commenting on the method

roadbikeChris

I think I will take the bike to the bike shop tomorrow and get it on a level floor and recheck it. The rear tire is 1/4 taller than the front. And the level I used bears that out. I don't want to create a lot of controversy here.

slow_runner

My 2c.
Cumulative error?. Your rims appear to be differing types as are your tyres? Yes?
Image perspective may not be square on?

Unless it is a 'funny bike' for a sideshow all slight variables can be compensated for with height/angle adjustment.
Why to the bike shop?
Does it ride well, no dropping to one sides, keeps a straight line?
Save yourself some time, money and possible jesting(?).
Do you have a tape measure?
If you are wanting some perfection, use Pythagoras (3,4,5) to check for square (or a square, or level).
You do not require a perfect level surface; a 180 degree flat surface is all you require.

thook

well, level or not top tubes are pretty controversial

roadbikeChris

The rims are matching ARAYA 700c

Unca_Sam

roadbikeChris

Hilarious!!!!!

slow_runner

Here is the thing with levels, especially the garden non-calibrated variety, they are often 'out'. Hook and others will be aware of what I am speaking. A long base level will give a more accurate reading whether it is this bike frame, a wall, whatever,
So to eliminate error requires a better level or as a 'need must' the level needs to be reversed and viewed again.
Regardless a levels amount of response or rated accuracy, always confirm the level is indeed an accurate one by reversing the level and ensuring the bubble has not shifted.
End of amateur instruction lol.