I have a Surly Cross Check and I have seen it set up with dropped bars as well as a straight bar.

What is the difference between a road frame, a hybrid frame and a touring frame, all of which I have seen the Cross Check set up as.

Thanks,
Ian

The difference between a road, hybrid and touring frame is mainly the type of riding it would be most suited to. This is not to say they are unsuited to cross purposes but a builder tries to build a frame to meet the needs of rider and part of that is the intent.
A road bike should be responsive, quick and efficient. A touring bike would normally be well mannered, comfortable over long distances with baggage.
A hybid (if I understand your meaning) would be stable and easygoing with upright positions and with clearance for wider tires.
To accomplish these differing purposes the builder adjusts the geometry and materials to give the bike the necessary characteristics.

Thanks for the info Wulf.

i was about to start my own thread, but this one almost answers things, but...i would like a more thorough explanation of geometry...without getting into measurements and millimeters...

i realize and understand the differences in frames in a general sense, but here's the specifics i am confused about...

i've noticed some mountain bikes (hardtail) have really aggressive geometries (top sloping tube to be exact) as well as some 'commuter' bikes...and even some comfort bikes.

what's the advantage of this aggressive angling? in MTB i hear it is responsiveness. in comfort contexts, i hear it is simply to make it easier to get your leg over...and straddle. the trek soho s (at least one of the smaller frame sizes) has a really radical slope. now is it the wheel base that makes a difference? i read somewhere that some comfort bikes are simply low end MTBs with higher stems angled sharply up, cushey seats and fat tires w/o knobs. or is there a frame differential as well?

my whole focus is mainly on frame dynamics/applications.

i'm sure my questions will garner repsonses that will garner more articulated questions. i hope!

if you're just asking about sloping top tubes, in MTBs it might be to get more clearance. In road bikes, it was originally done to reduce the number of frame sizes they needed to make. Nowadays, it's the most common style. Most custom frames still have horizontal top tubes though. The frames with a sloping top tube may be marginally stiffer.

One real advantage I see is that you can have a higher front end for comfort and still have reasonable step over height. Otherwise it's probably mostly a stying issue.

The main advantage of sloping top tubes on agressive bikes is that you don't fall on them when you come off, or can put your foot down in certain situations. There are other features like weight but the crash aspect seems the main one. The same clearance is beneficial in bikes that may suit riders in non-sport clothes etc... So the look is the same but not for the same reason. I've been riding MTBs from the begining but I'm no expert on their frames.

so, are there other differences like wheel-to-wheel distance? seems like the comfort bike could easily become a decent hardtail or totally rigid set-up if one simply put on knobbies...a MTB seat, lowered the stem, adjusted it forward, possibly change the handlebars....?

or do they make such frames less durable?

In the 70s aand 80s the ride characteristics were controled mostly by geometry because steel was the main material. Road racing bikes had stiffer frames made with shorter wheelbases between 38-40 inches and with seat and head tube angles around 73-74 degrees. Touring bikes usually had wheel bases from 40+ inches and angles around 71-72 degrees. The early aluminum bikes like Klein and Alan followed these same trends, but in different directions. Now the ride is controled by choice of materials with carbon and plastic combined with steel alum and titanium. Mountain bikes are a whole nuther paradigm (I love it when I can use that word).

This is nonsense. Responsive to what, in the sense of doing what? Quick in what circumstances? Efficient - *every* bike should be efficient.

So much for bikes like the Sirrus, which are stretched out, flat, and can *maybe* jam a 32mm tyre in...

Oooh, that's very specific!

Anyway:

- A road racing frame is gives away cost and toughness to decrease weight. The frame angles are optimized - by making them steeper - to give the sharp, twitchy handling needed to fight for position in a dense pack of riders. Wheelbase is cut down for the same reason.

- A dedicated criterion bike is like the road racer but ideally has a higher BB, so it can be cornered at steeper angles while pedalling without pedal scrape.

- A track bike have even steeper angles as fighting for position is even more important

- I know less about triath bikes, but I believe they give cornering ability to optimize straight-line speed. I think designs are still in flux - see https://www.slowtwitch.com/mainheadin.../geometry.html

- A tourer has more relaxed angles and longer wheelbase to give the bike less twitchy handling. Of course toughness is a higher priority, and the BB may be lower to increase stability.

- A hybrid is a marketing term that may mean almost any damn thing from an almost-racer to a sit-up-and-beg bike.

It's a mistake to believe the marketing miasma that racing bikes are more efficient: any well maintained bicycle power train is extremely efficient, losses due to frame flex are a fairy tale for the credulous, and aerodynamics are down to bike set-up rather than bike category - a hardtail MBT with low, narrow flat bars and good slicks will run with even a crit bike on the flat and just fall back a little on climbs because of its weight. It wouldn't do well in a race however because its geometry would put the rider at a disadvantage in the fight for position. This is probably the second biggest thing that people who don't bother to read engineering papers on bike design don't get about the differences between bike categories: All bikes are efficient, if reasonably well maintained, and the engine is the rider. Differences in geometry are largely about making trade-offs in steering behaviour and stability.

(The biggest thing is the cube/square root relationship between power and speed at high/moderate velocities.)

This is mostly wrong. Materials choice combined with aspects of frame design like tube diameter can alter secondary characteristics like comfort and perceived stiffness; it can't alter steering and stability the way that trail, wheelbase, and head tube angle can. Modern carbon fibre bikes have very much the same frame angles as classic Steel Age bikes.

meanwhile, that is a dense and informative article for sure. answers alot of questions, but i do think simply riding a bike, knowing what you want to do will answer just as much. thanks!

I absolutely agree. You might well be better off with a particular MTB for touring instead of a tourer, cyclocross for commuting, etc. So much depends on body shape and weight, local conditions, riding style. Don't get trapped by categories is some of the best advice you can give - second only to don't believe that a $4000 racer will do your commute significantly faster than a tougher, more comfortable and cheaper bike.

that is about the best and most honest and confirming info i've gotten here in the last few weeks.

i trust my gut, but there is a balance to knowing how to ask questions and get that accurate/dead-on response.

i think i've been looking for a reason to get rid of this bike i have (trek 16.5 navigator 200)...a comfort bike is a comfort bike they say...but my minimal changes have turned this into a really megahybrid, useful in more applications than i would've thought. what might make it even more useful is simply have two sets of tires on hand for quick switch outs.

two things this bike won't be doing and that is no problem: hardcore mtbiking...competitive road/track. almost anything in between is quite doable.

now it's a mean little urban-utility bike that hits alot of off-road with a snarl. even with it's shocks to be removed soon



edit:
interesting frame here. a 29er, but this is the aggressive look i was talking about earlier:

https://www.918xc.com/index.php?p=product&id=4&parent=24

my trek frame looks quite similar to this...

"Aggressive?!?!"

That's a style and fashion word.

29ers have top tube height issues - combination of a high BB and huge tires, so usually get curved or severely sloped top tubes. Nothing aggro about it, the bike might just handle like a cruiser depending on the rest of the design.

Back to the original question: "What is the difference between a road frame, a hybrid frame and a touring frame, all of which I have seen the Cross Check set up as."

Road and touring bikes are usually set up with drop bars, which are ridden mostly with hands on hoods, which changes the distance from saddle to hand position changing the needed top tube length relative to straight bars. Touring bikes are expected to carry large loads and travel relatively slowly, stability is more important than ability to lean into a high speed corner, or to change direction quickly - so the tourer get a lower bottom bracket which brings down the top tube and the thing is more manageable.

Now none of this is so extreme (except maybe the cockpit length) that one bike can't serve multiple purposes. However specialization has been sort of a selling point and a lot of road bikes are built with race dedicated geometry and features to the point that they're a pain to use for anything else. The Cross Check is a good example of an all around bike. If it were a pure 'crosser, there'd be no rack or fender eyelets or even bottle cage bungs.

That sounds very sensible. An even more extreme example might be one of the MTB based 26'' crossers that quite a few people on Retrobikes (probably the most mechanically adroit of all cycling forums) have built as all-rounders - tough as hell, superb braking and cornering from the fat contact patch, damn near as fast as a race bike. Sort of like a Spec Tricross but more so. This is a nice one:



This one is singlespeed, but I've also seen them built up with bar end shifters and brifters (you just need to change the front derailer for a road one.)

There was also a bit of a weight advantage...

Meanwhile, I like that SS monster-crosser. Gotta build myself one someday, soon.

Thanks to everyone who responded. There is a lot of good info here.

Ian