Tiglath

I am looking at the Parlee Z2 and Z3 and initially I wanted an old style bike with a level TT, that would be the Z2; the Z3 is the same bike but with a slanted TT geometry. I am no expert but I understand that, as far as geometry affecting ride, it is not an important measure. It does screw up the sizing though, when the size is taken from the seat tube. On a level TT my size is 51, on a slanted one 48. To me, it boils down to looks.

I like the look of my Cinelli Supercorsa with a level TT, and I thought that was my preference, but after getting a Cannondale CAADX with a slanted TT, it's beginning to grow on me.

Terrible problem, isn'it?

What's your taste?

Lazyass

Level. I despise compact frame geometry, even on MTB's. I hate they way they're sized and I think it looks stupid. Manufacturers do it because they can produce fewer frame sizes and save money. And I don't care who disagrees, you aren't changing my mind, I've already heard all the arguments and drama, so don't try

rms13

It doesn't screw up sizing as much as it makes it harder to understand for people who are used to bikes with level tt. Most people generally start with tt measurement for sizing. If a bike has a slanted tt or compact geometry you should still read the geometry chart the same way. The bike will list top tube or effective top tube. So if a bike has a 550mm top tube than it's more or less equivalent to a size 55 standard geo bike whether the bike is called a Medium, 55, 52, 50 or whatever

rms13

...and yeah me too. I have a CAAD which most people refer to as traditional geo even if there is a slight slant and I have an 80s steel bike with level top tube. I like the aesthetics. I had a Giant TCR with compact geo and honestly didn't feel much different , just looked different

Blue Belly

All things equal, a smaller triangle should be more stiff. So theoretically the frame could be built lighter to attain the same stiffness. For the record, I like traditional geometry.

Lazyass

That's one thing I like about the Cannondales.

Stucky

Makes no perceptible difference in the ride/performance...so it's just a matter of personal taste. Heh, I can't decide which I like better, either, so I have one of each type of bike. As for sizing, compare effective top-tube lengths, that'll tell the story.

Tough choice, though. I like the classic good looks of the level tube; and the fact that they're not very common anymore; but the slanted tube looks better with the other modern features on newer bikes..... I'd just pick whichever bike you think looks better, overall.

rpenmanparker 

Providing the seat tube angle is the same on both bikes. For every 1 degree larger seat tube angle you will need about 0.5 cm less top tube to give the same fit. That is because you will need to push you saddle back about 0.5 cm to get the same relationship to the bottom bracket. So you will effectively be lengthening the top tube. You would want to start with a shorter one. Just the opposite for slacker seat tube angles.

Lazyass

Yes but bikes with compact geometry tend to come in fewer sizes. For instance, the Giant Defy comes in six sizes, 3cm apart. The CAAD10 comes in 8 sizes, 2cm apart, as it should be.

AlmostTrick

Both can ride and look great. It's the total package that does it for me, not just the frame style.

BoSoxYacht

I like a level TT, but a slight slope is okay too. I need a TT that is slightly shorter than stock because I have a short torso + very long legs. Most stock frames with a level TT that is short enough for me, have a small headtube that forces the bars to be too low.

Old Italian bikes fit me well, but not many companies build them like that anymore.

StanSeven

But sometimes you need a longer sestpost. That negates much of the weight savings

Blue Belly

Ansolutely it does. But, if stiffness is your goal, a few extra grams may be worthwhile. It's all in the mindset of the builder.

Pistard

like coke or pepsi, I got both.

BillyD

Love the level TT, hate the slanted.

RJM

I guess I don't care so much or it isn't the main thing I see when looking at a bike. I care more if the entire package makes a good looking bike. For instance, I think the Trek Domane and Trek Emonda are good looking bikes depending on what wheels/groupset/color scheme the bike comes with. The Trek Factory Racing color schemes and builds for either the Domane or Emonda make one great looking bike, IMHO. Most other big bike companies have some pretty good looking bikes in their lineups too.

My personal road bike has a pretty level top tube and I think it is a fine looking machine, but it isn't because of the TT.

benlees

I love level top tubes, and all my bikes have them, but I wouldn't turn my nose up at good riding bike without one. Something like a Gunnar Roadie, Soma Smoothie, or the new Kona Kapu might be nice...

gsa103

Slanted top tubes all the way. As someone with a long torso, on properly fitted level TT bike I have negative standover clearance.

a1penguin

I'm old and like the level top tube. But being female the slanted top tube offers a wider range of bikes that can fit me. I had no trouble finding cf bikes that fit me as they were all compact frame. I have an inch between the bar and my anatomy on the Synapse. If it had level tt, I would have been SOL. I also find the non-cylindrival shape of the down tube creepy. I've gotten over it.

Tickstart

I like classic look more, but slanted has it's charm too, it lines up with the rear tyre's tangent nicely. I think the slanted top tube is for short people, as the seat tube would be ridiculously extended for a normal size person. This is merely a thought though.

Stucky

After thinking about this, I now realize that on metal bikes, I like a level top tube; and on monocoque CF bikes, I like the slant, as it melds better with the fluidity of the rest of the CF frame. Slanted TT on metal just seems wrong- as does level on a monocoque CF frame. My first road bike was AL and had a slanted TT....I sold it.

rpenmanparker 

Some folks think that the 6 degree stem melds better with the slanted top tube. Horizontal stems were the norm during the time of the horizontal top tube. It makes some sense, but I don't get all excited about that match.

StanSeven

Yeah but there's no real need to makes sizes one or even two cm apart now. With stems that come in so many lengths and angles as well as seatposts with varying setbacks, you can fit the majority of riders easily.

Square Wheels

I have a roubaix, I really like the look.

Lazyass

But different stem lengths and seatpost setbacks change your position on the bike. I know exactly how long I want my TT and stem down to the mm. And I don't want my saddle rails sitting above my rear caliper. Could I live with it? Yes. But I don't want to. I've heard all the arguments like yours 100 times. My mind isn't changing.