bashley

I'm comparing geometries between a range of gravel/adventure/touring bikes with 700c vs several randonneur type frames with 650B's. Sizes either 54,55, 56 or medium.

Here's a selection of 700c bikes (all steel versions)

• Vaya, Salsa
• Beyond, Bombtrack
• Rove, Kona
• Sutra, Kona
• Marrakesh, Salsa
• AWOL, Specialized
• Sequoia, Specialzed
• 520, Trek

• Average Stack: 595mm
• Average Reach: 386mm
• Average STR (Stack to Reach Ratio): 1.55

The 650B's (all steel)

• Gran Randonneur, Soma
• Velo Routier, Toussaint
• Polyvalent, Velo Orange

• Average Stack: 553mm (42mm less than the 700c average)
• Average Reach: 390mm (4mm more than 700c average)
• Average STR: 1.42 (13 points less than the 700c average)

On the one hand, I recognize that 700c to 650B is apples to oranges, and yet, on the other, I read many references to more voluminous 650B's are pretty close to the same diameter as narrower 700c's.

I'm wondering if posters more seasoned than I can explain why the average stack of the 700c's is so significantly higher, while the reach for the same 700c's are minimally less?

Does less BB drop for the 650Bs account for some of the difference in stack averages?
As a general rule of thumb, are rando bikes designed for a more stretched out fit?
What am I missing in the analysis?

Motive? I'm torn between these two genres. But I can't confidently reconcile the geometrics disparities. I'm looking for a reasonably relaxed, semi-upright riding position. I'm an older rider, like 66. Weak core. Average flexibility. Height 175cm. Weight 185lbs. 31" inseam, longish torso. Slow speeds, no rocket sprints. I perceive many ride benefits with wider tires, the lower pressure, stability, comfort, safety. I want an all-rounder, to carry stuff on the front, on the rear, commute, short overnighters, multi-surfaces.

I lean to the randonneur frames which I can build to my liking with friction shifters, subcompact crankset with shorter crank arms (160-165), etc as opposed to having to accept the manufacturer's conception of what they think I need.

I've got a bunch of old C&V's but none really suitable for conversion without expensive alterations hard to justify. I have plans to clear out my old inventory.

If I had to pick tomorrow between just two bikes, it would be between two very different bikes, the Soma GR or the Bombtrack Beyond.

I have no 29er experience, so no idea what my impressions might be.

Any insights, I'd much appreciate.

Spoonrobot 

The stack for those 650b frames is so much lower than the other bikes because they are steel and made with thicker, lower quality tubing and having a short head tube (and susquent stack) allows the manufacturer to showcase a lower weight for a given frame size. It also allows for a lower standover height.

These frames are designed to appeal to a demographic interested in curved positive rise stems as well as level stems with extreme extension.

If you are serious about rear loading please do some research on how a low trail bike handles with a rear load. Generally this is not recommended for anything more than token weight.

bashley

Thanks Spoonrobot. I neglected to mention that ALL of the bikes in both lists are steel, not just the 650Bs. Yes, I understand the liability of rear loading on low-trail bikes. By far, the bulk of my loads would go upfront, either in a square randonneur bag or low-rider packs.

Given my factors, which way would you go?

IK_biker

I would go building up the Soma GR v2.

In the last 3-4 years I have entirely shifted to distance riding, some of it - on forest roads, most of it - on paved roads. My stable of bikes cover this very well.

2 months ago I decided to retire an old Aluminum frame (saw a crack-like suspect in the BB area) bike I used for touring, and get a new tourer built for my way of touring - for light loads mostly carried in front.
Got the Soma GRv2 frameset, built it up, and am very impressed. The low trail does its thing nicely. The bike as built is sufficiently lightweight and rides like a dream both loaded and unloaded. To the point that it competes for my everyday rides with the Ti Lynskey bike I had converted to 650b a few years back.

Spoonrobot's comment is out of whack, I would disregard it.

This Soma frame uses Tange Prestige tubing, and while this is not the Prestige of old, it is still high-quality HT steel, the top tube having wall thickness of 0.8-0.5-0.8. I have ridden low-quality steel bikes (Surly long trucker comes to mind), and the Soma is far from it in weight and responsiveness.
Meanwhile, I have watched the 2-year progress made by VO to get their new Polyvalent frame to the market, and am pretty sure that it is another lifeless boat anchor in the long trucker category...

And yes, the lower stack to reach ratio is because many distance riders prefer to go long and low.

Edited to add:
The bike weighs 24.5 lbs with aluminum VO fenders, front racks (yes, plural), and a heavy Brooks saddle. I put friction shifters on, and a triple.

tyrion

Interesting. Got any pics?

danmyersmn

FYSA I had an AWOL and it is a beef of a bike. It is great for full load touring and it handles it with ease. light touring or bagless and it is a slug. I replaced mine with an All City Space Horse and I prefer it over the AWOL. The AWOL is a great bike but it sounds like it is not as precise an arrow as what you are looking for. The AWOL should be compared against something like the Surly Disk Trucker and I don't see that on your list.

bashley

Thanks for weighing in, IK. Your sensibilities with the questions resonate pretty much with mine. I could understand the "long and low" preference, but this would be a lesser priority insofar as my functional needs are multiple and various, as in "all-rounder". And this is part of my struggle between all the other benefits of the 650B randonneur that you're obviously enjoying and the more upright, longer trail 700c bikes.

Your Soma GR as you describe the full outfitting at 24.5 lbs is 4 or 5 lbs less than I would have guessed. Nice!

Would you mind, IK, sharing your choices for front rack, shifters, cassette and crank? In building up the drive train did you target what you wanted/needed for low end gearing?

Comparing your Lynskey with the GR, using stability, security, safety (3S's) as criteria, what are your impressions?

bashley

I'm intrigued by your story, danmyersmn. Obviously, you discovered first hand that bike handling (not to be a slug!) emerged as a game-changing priority for you. To go to the extent you have in abandoning your first choice, I assume, at some personal financial cost, is a persuasive testimony.

If handling was an AWOL deal-breaker for you (or a source of buyer's remorse!), were there any lesser factors that also came into play in your decision to go for the All City Space Horse? I'll look up this bike myself and add it to my list.

IK_biker

As usual, the bikes I build are tailored just as I want them including the gearing. I have done numerous builds for myself, my kids, and a bunch a friends.
The Lynskey as built (started with a new Peloton frame) has about 60 mm trail, and is a lovely machine. It becomes just a bit squrelly on uphills over 15% if I let my speed drop below 3.5 MPH while seated. The Soma does not have this problem, even unloaded. Otherwise, both are very precise in handling, The Lynskey of course accellerates a bit faster. Both bikes are somewhat springy when pushed hard. I ride the Lynskey with 38 mm tires, while the GR is on 42s. Both are a joy to ride, but I have not taken either of them on a single-day ride longer than 90 miles. The GR has been only tested as a tourer (with small front lowrider panniers), however the winter in my area does not allow for any real touring. Just after Thanksgiving I had the touring rack removed to better enjoy the bike on daily rides.

The Lynskey is intended for everyday riding, including overnighters every now and then, while the GR is mainly for touring.

As to security and safety, I completely trust all bikes I have built, considering that I have wrenched on bikes on and off for some 51 years now...

I think your concerns about the lowish stack are over-inflated, as the beauty of a quill stem is that you could easily raise it to your liking. It is a valid concern in case you considered threadless stems instead.

Here's the list of components I used:

IK_biker

LOL.

My bikes are for riding, not to photograph them.
The only pic I have is the one I always take of a new bike when I start monkeying around with saddle tilt angle - this way I document what I've done, log my impressions and comfort/performance observations during rides with the setup, and can easily revert to a previous saddle setup if needed.
In this case I have the tilt apparently nailed, as it felt and feels just right. No plans for further adjustments.

tyrion

I wanted to take a look and see what components you had on that 24.5 lb. bike but I see you've provided a component list.

bashley

Thanks for the full profile, IK. Very comprehensive, A to Z. Coincidentally, I've included the triple Sugion crankset you've got in my short list, including the 165mm crank arm. And the 650B x 42, supple tires too.

You're probably right about my throwing too much emphasis on the low stack. I haven't done any first hand comparisons, and I may be biased because the dropbars I have are traditional, with slightly sloped tops and fairly deep drop, no flare. The Nitto Noodle is flatter on top with a bit of sweep back.

tangerineowl

Bashley,

Have a look at the Crust Lightning Bolt frameset.

There's a few comments on it over at '650b' on Google Groups.

bashley

Yeah, thanks tangerineow. Interesting option the Lightning Bolt.

Road Fan

I would go with a 650b low trail. 650b because it is more cushy and stable on my local roads with fragmenting pavements, with no apparent downside. Low trail because i like the handling and easy steering. I have a Trek 610 (700c) with a custom made low trail fork and a Terraferma 650b with skinny thin wall tubes that give a cushy ride - I'm not sure if it "planes." But for both i have not seen any shimmy or other issues with a good sized front or rear saddlebag.

On my high trail roadie bikes ive had the same squirreling while climbing below about 5mph, and it is much less with low trail.

Geometry-wise, the GR is in my ballpark. I like the cushiness of thinner-wall and smaller outer-diameter tubing. I think those attributes are against the high stresses imposed by disk brakes, so I'd go with a caliper-brake frame. I've gotten along swimmingly and safely with rim brakes since the late 1960s, so I don't feel the need for disks - the Crust gets a lot of kudos, but it would not be for me.

Road Fan

In that vein, one bike I've been interested in for a while is the Boulder All-Road though it is more pricy than what you have been looking at. But you could consider its design as a model for what might be your top bike.

Also, I like a laid-back seat tube because I like my weight balanced over the BB without cantilevering the seat post off the back.

IK_biker

The stresses imposed on the main triangle of a frame by disc brakes are no higher than those in a bike with rim brakes.
The stress differences are only in the forks/stays.

elcruxio

Strange. The Soma is made of chromoly steel, AISI 4130 with double butted tubes.
The Long haul trucker is made with chromoly steel, AISI 4130 with double butted tubes.
Both have the top tube thicknesses at 0.8/0.5/0.8mm
So where's the difference in quality? I can't see it.

Also, I have to say that even though the LHT is one of the best heavy load tourers in the market right now, it's still plenty responsive for me and long distance riding. Generally I prefer a bike to go straight well if I'm riding long distance, not be a twitchy piece of work. I haven't tried the soma though so I can't know how it rides.

But overall, I think you are mistaking different frame properties for different uses with your preferences and then attributing that to quality. But it's not about quality is it? It's a tool for a job kind of thing. There's a very good chance both the long haul trucker and the Soma come out of the same factory. The difference in steel is purely that the one has a brand name and the other doesn't. Doesn't mean anything though.

Road Fan

You mistake my meaning though I see I was not clear enough. Many thin wall randos have thin wall seat stays and fork blades, especially the lower half of the fork blades. Th Boulders are a good example of this.

IK_biker

This is not about frame quality or materials, it is about ride quality.
I don't really care what steel the Surly LHT is made out of, although its frame is definitely heavy.

I have been riding bikes for some 52 years now. And when I say "ride" I mean really _ride_ these them damn bicycles.
My body has become a finely calibrated instrument delivering accurate perceptions about the bikes I ride, perceptions I trust completely.
Some of my steeds felt dead during a ride, others felt lively, and yet another bunch - anywhere in between. I am familiar with this spectrum.
When I test rode a LHT a few years ago, I had it adjusted to my cockpit preferences, put my own saddle and pedals on, and off I went on a several hours hilly ride. I really wanted to like it. However it felt as one of the deadest bikes I've ever ridden.
D-e-a-d.
The Soma GR I built feels on the other side of the spectrum.
That's all.

elcruxio

Well no wonder, the LHT is a heavy load carrier whereas the the GR is not. They're bound to be different in both geometry and frame properties.
The LHT can carry a full touring load without a hitch whereas the GR will struggle. The GR is lighter and more nimble.
I mean the initial comparison was like comparing a mountain bike to a road bike. Completely different vehicles.

Road Fan

bashley,

Did all this discussion end up helping you?

fietsbob

650 B is 27.5" in the New expanded MTB world..









.. MAP Bicycles | Handmade, Custom Bicycles | Chico, California. seen one, he does nice work..





...

bashley

Yes, very helpful, thanks for asking. A variety of perspectives emerged, stuff I hadn't given much thought. Materials, angles, trail effects, brands and more. I'm actually considering a custom build so all the comments, criticisms and advice here has practical use. Gabriel Lang of Altruiste bikes just won Best in Show at NAHBS 2018 in Hartford and as it happens, his shop in the wilds of New Brunswick is only 90 minutes away from me in wilder wilds of Prince Edward Island.

Step one, however, is also practical, that is, unloading a dozen or so old bikes, turning fixed assets into liquid ones.

Thanks to everyone who weighed in on this thread. Appreciate your help.