Track vs. road geometry?
 

How would a frame with road geometry compare to a frame with track geo? More specifically, I'm comparing the iro phoenix to mark v.

track geo will be twitchier and less suited for riding longer distances. Road geo will be more comfortable on the road. That said, it's not going to kill you to ride a track bike around on the road. It's all your preference.

road: straight lines

track: tighter turning

Road bikes come in a wide variety of geometries depending on the intended purpose. Touring and commuter frames tend to have slacker angles and enough clearance under the fork crown and brake bridge to mount mudguards. Stage race frames will have a shorter wheelbase, more upright angles and less clearance. Criterium frames often have a higher bottom bracket than stage race frames.

In general, a track frame will have a tighter wheelbase, higher bottom bracket, less clearance under the fork crown and seat stay bridge, and a harsher ride on rough pavement than a typical road racing frame.

that is humorous.

FYI, the Mark V's geometry is more relaxed than what you find on typical track bikes. It rides like a road bike.

why zat?

You want the geometry as steep as possible, for every occasion.

You can go in straight lines with a track bike too.....

road bike: relaxed geometry, longer wheelbase(usually), and better for straight line riding

track bike: shorter wheelbase, steeper geometry, and usually very nimble steering, good for track (not necessarily bad for street)

there isnt really a set track nor road geo. the geo changes depending on what event is being done in either type (sprinting, pursuit, touring, crits, etc)

if you can try some bikes with steep geo, like older model pistas, some keirin frames, not sure what's new with steep geo. is the rush hour very aggressive? kilo's are an in between for steep "track" and slacker "road" geo.

then try some bikes with slacker geo, like iros, se lagers/ dawes sst. etc.

Because it's way too boiled down, and also it's incorrect. A lot of track bikes have more trail than many road bikes. There are a few different factors at work. One is head tube angle, which affects how fast a bike's handling is. The other is trail, which is a measurement that is the combination of rake and head tube angle. Trail is how far the contact patch of the tire lags behind the steering axis. Know how a shopping cart wheel spins around to the back? it's because it has trail. The more trail, the more self-correcting or stable a bike's steering is.

Track bikes don't need to corner; road bikes do. They may need to handle fast - hence steep head tube angles - but they also need stability at speed - hence less rake to increase trail (yes kids, less rake means more trail! were you paying attention above?).

On the flip side, road bikes tend to have shallower head tube angles which are going to provide some more shock absorption and help neutralize the handling a little bit. You don't want fast handling when you're going 55mph. But before I hear jive about road bikes being made to go straight, dive into a 90 degree corner at 34mph and then talk. So they have more rake so that their trail measurement isn't too great. A little more rake can also help with absorbing some road chatter, as a lot of road forks do flex nicely.

Resources -

Dave Moulton's post on the subject of front end geometry:
http://davesbikeblog.blogspot.com/20...le-bit-of.html
Blog post with a bunch of links:
http://nooneline.blogspot.com/2009/0...ube-angle.html
Don Walker's write up of track geometry:
http://www.urbanvelo.org/issue3/urbanvelo3_p44-45.html

...and to answer the OP's question, front end geometry is only a little bit of the general differences between road and track geometry - each of which vary enough to the point where there's overlap. There are some other differences in seat tube angle, chainstay length, and then other design factors that might not strictly fall under the "geometry" category; as well as rider set-up, fit and weight distribution variables.

Don't make the mistake of thinking the steeper the better for all purposes. Steep track bikes are fun but are not the be-all and end-all.

I was under the impression that stage race frames - like LeMonds and other bikes with "epic geometry" - had really long-and-back geometry, like parallel 72s with long top tubes.

there we go.

Test ride some bikes and see what you think. I didn't care for the Bianchi Pista geometry; liked the San Jose better. (also didn't care for the track bars but that's another thread)

Your style of riding, what you use the bike for, should help dictate the geometry. Fashion also plays a part; how much is up to you.

Surely you jest, dear boy!

I like what queerpunk said.

I have a slightly different perspective on it, but just different and not more or less right.

One can design a front end geometry that will produce a relatively neutral 60 mm of trail (neither "twitchy" nor "dead") by combining a steep head tube angle with a short rake, or by combining a less steep head tube angle with a longer rake.

One can see this for oneself by downloading the Trail Calculator from Anvil Bikes:

http://www.anvilbikes.com/images/1064634020.xls

Using the above calculator, one might discover that a steep head tube angle of 75 degrees and a short rake of 28.5 mm will create the same amount of trail as a shallow head tube angle of 72 degrees and a long rake of 46.1 mm; or, a relatively neutral trail of 60 mm.

However, in general terms (and disregarding wheelbase, rider position and rider weight), the steep head tube angle and short rake combination will handle better at lower speeds and the shallow head tube angle and long rake combination will handle better at higher speeds.

So, since I value low speed (15 mph) agility over high speed stability, I ride a bike with a steep head tube, short rake, short wheelbase and a significantly setback (35 mm) seat post.

the san jose has less trail.

no one was arguing differently.

but i think it is highly dependent of what Pista we're talking about, as the geometry has changed a lot over the last few years.

i was just stating a fact.

LeMond's have slack angles and long top tubes, but that's LeMond's preference for a stage bike. Look at e.g. the old Peugeot PX-10s for a more typical stage geometry. Plenty of TDFs were raced and won on PX-10s.

Bianchi discontinued the "track" geometry of the Pista on the 2009 and 2010 models.

The Pista now has a head tube angle and rake similar to if not the same as Bianchi's road bikes.

Back it up with numbers then. ;)

For what purpose?

i am trying to steal your eagle.

in a previous post, i calculated the san jose to have 54.1mm trail, which is faster than most supposedly tight turning track geometry bicycles.