MattTheHat 

ChuckD6421 

Oh, we're all brilliant at something now MattTheHat. I'm sure you'll find yours soon!
(Dad-of-Teen mode off)

This interested me as I come from a competitive roadie/extended tourist/hardcore commuter background, and having raced crits and found them not to my liking, and even trained on tracks and found them to be not unlike roller derby, I came to appreciate frame geometry. I am of the road. My (very) simplified observations of your experience follow:

I did a little digging because, a. you mention the Cannondale and did my racing on one of their early "Beer can" bikes back in the 80's and enjoyed modest success and b. I now have around 10K miles on a Domane 5.2. I found that all three of the bikes you mention have similar head tube angles of around 73 degrees, or, 17 degrees from vertical. That puts them (predictably) biased toward the relaxed side of control which is what you'd expect of an endurance, comfort-focused road bike. Interestingly where they depart though is in fork rake. Where the Specialized and Domane had around 60 mm rake, the Cannondale had 40 making it a somewhat twitchier ride. Think of the difference between a kids' stingray bike and the rad machine the odd kid made when he tried chopper forks, and the front wheel basically flopped back and forth on it's 7 foot rake. Similar thing.

So yeah, the Cannondale's gonna take some mental adjustment to feel relaxed on. There's other things that separate a frame that rides "like it's on rails" and one that a sneeze will put you in the ditch; chain stay length for one, seat tube angle for another.

Sources:
Cannondale 1996 catalog https://vintagecannondale.com/year/1996/1996.pdf
Specialized (I don't know why they can't put this on their own website, needed to look elsewhere) https://www.mikesbikes.com/images/li...geEliteDSW.gif
Trek Domane (Another one who thinks we're too dumb to care) trek domane frame geometry | Allframes5.org

MattTheHat 

Thanks for the links!

To be completely honest, I've never studied frame geometry much at all. I understand the effect of most of the geometries listed but I've just never spent any time thinking much about them. Looking at the links you offered, I took some time to compare the Diverge (if the geometry is the same for the 2018 Diverge Comp) to the R500. My Diverge is a 56cm frame, the R500 is a 54cm. There are several things that surprise me. One is the standover dimension. I would have never thought the standover was greater on the R500. It's only 4mm greater, but the R500 feels considerably shorter, possibly because the top tube is essentially flat.

Wheelbase is considerably shorter on the R500 (by 35mm). No surprise there. The seat tube angle is within .5 degree, but the length is 100mm longer on the R500. That surprised me. The fork offset is greater on the Diverge by about 8mm. I would have thought it to be even greater than that. There is no reach spec on the Cannondale catalog, and I'm curious. I'm going to measure that tonight. I definitely feel more stretched out on the R500.

Looking at the two bikes side-by side, the two things that are most striking to me is the increased top tube angle on the Diverge. It's almost comical looking when compared. The other thing that stands out is the how much higher the bars are raised from the frame. I do have a 12 degree riser stem on the Diverge, but still. The end affect is that the bars on the Diverge are 75-100mm higher than the R500.

This is all very interesting to me. Looking at the numbers, the Cannondale handles about like I would have guessed. I wouldn't say twitchy at all, but definitely more responsive. But the ride quality difference is much, much greater than I had anticipated. I think the majority of the difference is from the stiff aluminum frame on the R500 and the 28mm tires compared to the 32mm tires on the Diverge (plus, they're tubeless, so running less air). I'd like to run 32mm tires on the R500, but they drag the top of the brake calipers.

The wife and I went on a short ride Saturday night after I'd romped around the neighborhood on the R500. I wasn't 100 feet down the street before I breathed a sigh of relief on the Diverge.

-Matt

bikingbill

"Endurance Geometry"

TrojanHorse

I have a 2012 Specialized Roubaix and a 2017 Pinarello Gan and there is a HUGE difference in riding position between the two. Of course, the GAN looks like a bike and the Roubaix looks like a dog hunched over taking a dump (with a head tube the side of my arm), but it is super comfortable for long distances. I like 'em both, they have different purposes.

TiHabanero

Looking at the geometry specs for the Diverge it looks similar to the mid eighties sport touring bikes. Trail for 58cm frame is 57mm, very similar to the old sport bikes. The big difference is the taller head tube (40mm taller), shorter chain stays, and the fork is about 20mm longer to accommodate wider/taller tires.

The use of a Technomics stem solved the shorter head tube issue on the old bikes to get the rider more upright. A longer length on the stem allowed the rider to gain reach. We changed lots and lots of stems on these things back then.

calstar 

I believe this is incorrect, fork trail makes a bike handle like it does, not fork rake; more rake = less trail which makes for a "twitchier" ride, less rake = more trail making the bike more "stabilized" in its handling characteristics. Touring bikes generally have a lot of rake and therefore less trail but the steering is stabilized by a front load such as panniers and/or handlebar bags.

regards, Brian

ChuckD6421 

And you are correct. Thanks for that.
Dave Moulton offers a good synopsis on the subject:






Dave Moulton's Blog - Dave Moulton's Bike Blog - Trail, fork rake, and a little bit of history

jpescatore

I've been riding at Trek 520 touring bike since 1996, was pretty comfortable and over the years thought I had it dialed in perfectly.

For 2017 I made a deal with myself: lose 20 lbs and buy a bike that weighed 10 lbs. less - mid-life crisis bike (I plan on living to be 120). I'm not a racer, don't do many tours per year, mostly recreational and long club rides - bought into the endurance, wider tires, disc brakes, etc. stuff and bought a Trek Domane SL6.

The geometry differences are slight but it was a huge difference in overall comfort on the first long ride I did, with my old seat moved over. I was really only expecting the lighter weight (especially wheels) to be the noticeable difference.

The Domane came with a discounted fancy Retul fitting session, which I did after those first long rides - the fitter moved my cleats back all the way on my shoes and raise the seat .5 inches or so - did a few long rides, felt even better. I went back and raised the seat on the 520, did an almost as long ride and still felt it more than the longer ride on the Domane.

So far, I'm a fan of the endurance geometry - but could be the placebo effect, too. Either way, I'll take it.

MattTheHat 

I'm not sure if it's the carbon frame, or the Future Shock or the geometry, or all of the above, but I really enjoy riding my Diverge. I enjoyed riding the Domane I rented, too.

-Matt