Salsa Vaya -- Soma Double Cross Disc
 

I have been riding a Salsa Vaya for the past few months and I am thinking about replacing the frame and forrk with a Soma Double Cross Disc. (I work in a bike shop and I have very limited access to brands. I have searched, inuired, and begged for more options but the only place I can get anything like this is from BTI.) I use it primarily for commuting 10 miles to work and long, meandering road/gravel rides around the city. I sometimes carry a rack and a pannier for work. I participate in the occasional gravel race. I have no plans for an extended tour that would require loading the bike down heavily.

I think the Vaya is a little overbuilt and cumbersome for my purposes. it`s steady and comfortable but it climbs like a cinder block. I want something a little zippier. Below is a comparison for the two bikes of about the same size, sizing based on effective top tube length. I am 5'9" and always tend to fit well on bikes with a 540-550mm ETT.

http://i819.photobucket.com/albums/z...psryxrc73b.png
(units in mm or degrees, or course. the Soma seat tube should be 500)

The main differences that I notice are that the Soma has a 2.5 cm shorter chainstay, higher bottom bracket, and steeper head angle. the shorter head tube would be a bummer if I have to use a lot of extra spacers, but I can live with that.

in short, would I be better off with the Soma? or would it be a latteral move and waste of time? I could likely sell the Vaya and come close to breaking even on a Soma, so the expense is not an issue, just my time.

I own the Soma and am also 5'-9". I'm riding a 54cm with a 90mm stem. I have more spacers on than I'd like. I imagine that a 50cm would require quite a bit more..

I'd get at least a 52cm.

ETT doesn't tell the entire story, better is to compare the reach and stack.

- The reach on the Soma DCD is 20mm longer, you'll need a shorter stem (-20mm) to achieve the same fit on the Soma DCD compared to a Vaya.

- The stack is 40mm shorter on the Soma DCD compared to the Vaya, your stem will be -40mm in height compared to the Vaya, depending on how you set things up you'll need more spacers or the stem will be lower.

interesting. I have been trying to wrap my head around stack & reach for a long time now. it is possible that I would have fit better on a 55cm Vaya, but the one I got was used and a heck of a deal. what do you make of this?

http://i819.photobucket.com/albums/z...psuzx6hzuq.png

here's something interesting. if I form a mathmatical relationship between the stand and reach between two bikes, I get this.

(nevermind, this spreadsheet was useless and made no sense!)

the math makes sense but I am not sure if that works that way in the real world. if this is correct, then changing the proportions of the stack on the Soma to match the stack on the Vaya means that a 52cm Soma has the same effective reach as a 54cm Vaya. or I am full of crap.

The fact that the same frame has different sizes but the same reach is a reflection of poor design. The Vaya and DCD have changing seat tube angle as the ETT changes keeping the reach the same, or slightly shorter even. So for your size there's no change in reach for several sizes in your range. Disappointing, esp since those frames are recent designs that should have some granularity for reach. It is a very common issue, easily noticed once you start really looking closely at sizing.

Yes, your math makes no sense, reach is reach, when you compare two frame's reach, it'll directly correspond to stem length. If you have a 100mm stem on the Vaya, you'll want to use an 80mm stem on the DCD to achieve the same fit.

I see what you are saying but humor me: if i have to add a ton of spacers under my stem because the head tube on the Soma is much shorter, would that change the resulting fit?

If I want a Soma with the same reach, I need a frame so tiny that it does not exist. I just wish there was a surefire way to compare the geo of these two bikes to know what is equivalent. No, no one within a few hundred miles has a DCD in stock to test ride.

I should have mentioned that I have been measured with a Fit Kit, which recommends a 56cm nominal frame size for me, and a top tube + stem length of 62.4cm for a road bike. If I were to use a 100mm stem, that would suggest that I should pick a frame with a 52.4cm ETT, which seems a bit short. I am more leg than torso, so maybe that's why I am always riding frames that are "too small" for me, but fit me just fine with a long seatpost.

Nothing wrong mechanically running a bunch of spacers. It looks ugly to some folks but no effect on your frame's longevity. You might even want a shorter stack than is possible with the Vaya. In any case, stack is stack, adding spacers to adjust stack will achieve the same fit.

Or run a shorter stem. What length stem are you running on the Vaya? Can you run a shorter stem? If you have a 60mm stem on the Vaya, maybe it's an issue, but if you're running a 100mm stem then it's easy, swap to an 80mm stem and you're good to go.

A proper fit should recommend a reach, not an ETT. ETT is meaningless for fit if the seat tube angle isn't included. Reach includes the effect of seat tube angle's effect on stem length.
I would start by getting your fit optimized on the Vaya, then use relative reach and stack to estimate your fit on another frame.

the reach on my current frame, which fits me, is 364mm. Soma does not make a frame with a reach that short. I would have to get them to build me a custom 38cm frame or something.

Not correct, what stem are you riding on the Vaya? Adjust it by -20mm for the same fit on the DCD, it's that simple.

Reach on 2012 54 cm Vaya is364.4mm

2012 Vaya 2 | Bikes | Salsa Cycles

I have a 100mm stem on it.

Then you'll want to use an 80mm stem on any of the Soma DCD frames in your size range (because they all have the same approximate reach in your size range). And you'll need to add spacers to the stem/steerer to get the same stack.

Frames don't fit like a suit, we have different stem lengths, spacers and adjustable seat position (height and front/back via the seatpost) to fine tune the fit. Almost all manufacturers are listing reach and stack these days because they are most important specs to calculate fit.

Once you have proper fit on one frame you can translate your fit directly to another frame using reach and stack.

So, as you can see from the link I provided above, my bike has a stack and reach of 593 and 364mm. How does that correspond to a Soma that will fit similarly? By that logic, the smallest 42cm frame is too long for me.

2.5 cm shorter chainstays will definitely make for a quicker-handling bike, albeit less stable. Also keep in mind that the Vaya climbs poorly because it is likely a ~25 lb steel bike. My ~24 lb Space Horse does not climb anywhere near as well as my ~17 lb CAAD9. I believe most of that is due to the significant difference in weight, as the Space Horse is actually much more stable climbing (due to the more relaxed geometry). On flat ground, there is only a marginal difference in speed between the two bikes (when they are both equipped with 25c tires).

I'm betting the frame weight on the DCD is pretty similar to the Vaya - the DCD is made from basic mid-grade steel, fairly similar to the Vaya (there is just less of it). So it is possible that climbing may not improve as much as you think in switching to the DCD.

If you really want a quick commuter/gravel bike, you may want to get something lighter. Consider a carbon/aluminum bike - I would actually look for a CAADX cross bike, due to the rather light weight and lower cost. Or, even something that is fully carbon fiber (if you can find it with disc mounts). Another weight-reduction option is cantilever brakes - it doesn't rain much in Austin, so discs are non-essential unless you ride often on muddy singletrack. Discs require more frame material and a stiffer fork - not good for weight/handling. Disc wheels may also be heavier than comparable rim brake wheels, which increasing rotating mass (leading to slightly worse climbing and acceleration).

Reach is without stem, you can translate your fit to another frame using it. The DCD reach is longer by 20mm compared to the Vaya, you'll need to change the stem by 20mm.

Your actual reach on the Vaya is the frame's reach plus the stem. Your actual reach is 364mm plus 100mm equals 464mm. On. The DCD the reach is 384mm, if you use an 80mm stem the actual reach will be 384mm plus 80mm equals 464mm.

To get the same fit you need to have the frame reach plus the stem length be equal a given frame. The limit of a rider fitting on a frame is the limit of stems, they come from 50mm~130mm.

Same thing for stack, once you find a frame with the right reach that allows a reasonable stem length then add spacers to get the right actual stack. How many spacers do you have on the Vaya?

Wrong, it's lighter by about one lb. Spacehorse is just another heavyweight QBP frame built more for no breakage and high marketing hype than ride quality, kinda like the Vaya. Can't be compared to the DCD for ride quality.

the reason I bought the Vaya was to replace the Pake C'mute that I had. I wanted to get rid of the bar-end shifters and the v-brakes. canti's were even worse. discs (Tektro Spyres) = less drama. I really like the style of bike I have now: steel, discs, brifters, big tires, etc. I don't expect to lighten up the bike by much without spending serious $$ and that is not an option. Cannondales and anything carbon are miles outside of my budget anyway. My choices are: learn to love the Vaya, or buy a Soma DCD. period.

confession time: I am riding the Vaya with the stock 42mm Conti Travel Contact tires. those things are beasts! I will try a more reasonable tire and see how that goes. if I can eliminate that as a variable, I will know if a more agressive geo-ed bike will work better for me. I went on a 40 miler yesterday with about 2500 feet of climbing, 5+ miles of gravel/singletrack, and some highway and urban traffic. it has rained a lot lately, so some of the terrain was muddy, puddle-y, and everything else was nice roads with a lot of long climbs. I don't want to give up any of that "go anywhere, ride anything" style of riding. if a bike with a shorter chainstay and higher BB will accomodate that and involve spending a marginal amount of money, I would do that.

IGH- thank you for demystifying reach! that notion has been bugging me forever. by that account I could set up the 50, 52, or 54cm Soma with an 80mm stem and get an overall reach that is pretty close. my Vaya has 45mm of spacers under the stem with a -7 degree rise and a 165mm head tube (just measured it). I am not against putting a reasonable amount of spacers under my stem, but I don't want a teetering tower a foot high either. I could also flip the stem up to get more hieght. in the end, I like to have the top of the flat part of the handlebar about level with the saddle or just below it. still not sure which frame size would accoomplish that, but it is a start.

I'd just ride the Vaya with some nice Paselas and enjoy. I'm riding almost the same thing, a Soma Saga Disc, it's a little heavy and stiff but screw it, good enough and I don't have to worry about flex when I load it up. If you want to spend some money, build up a second set of wheels with a dyno hub and lighter rims.

A 1 lb difference in frame weight is negligible (a whopping 4% if you compare a 24 lb bike to a 25 lb bike), and very few riders would even notice it.

On the other hand, a 7 lb difference (going from a 18 lb bike to a 25 lb bike) is a 40% increase an is very noticeable. I notice it every time I alternate between my two bikes.

A pound or two of frame or component weight is barely noticeable, and will make a negligible difference in climbing when all things are equal. When it starts getting to 4,5, 6, or 7 lbs, the difference is immediately discrenable as soon as you pedal away.

A DCD with the same wheels/tires/components as a Vaya will climb just marginally faster (though it will handle better). Neither bike is a good setup for flying up hills. My point is that switching to the DCD from the Vaya may result in better handling, but won't result in faster climbing because they are still both heavy, steel bikes.

It isn't when you consider ride quality. The 1lb saving is due to using thinner tubing which flexes more and makes the ride quality more "comfortable" (a subjective term for certain, the frame will flex more when thinner tubing is used). I never implied a 1lb difference makes a detectable difference due to the bike being lighter, I agree it means little, even when climbing.

I don't have anything against a heavy steel frame, as mentioned elsewhere, I have a Soma Saga Disc, probably made in the same factory as the QBP frames (Salsa/Surly/All City/etc). It's a heavy sucker for sure, esp the disc fork. I rely on the tyres to make up for the brick house ride and enjoy not worrying about failure from under-design when I'm screaming down a gravel road at 35mph....

I love my heavy, stiff Space Horse too - despite the weight, it is definitely a confident ride on gravel and singletrack. I kind of like noticing exactly ZERO wheel and frame flex when I stand up and hammer on that bike, though the ride quality sucks when I have skinny tires on it (currently I'm using it for 100+ mile rides since the riding position is much more comfortable than my CAAD). I also plan to tour on the bike this fall. But, nearly all of my Strava PR's are set on my road bike - I'm probably 10-20% slower going up hills on the Space Horse.

The Space Horse is definitely a confidence-inspiring ride. It rides gravel, single track, and poorly-maintained urban roads like a champ. Overweight? Sure. Don't care.

I am going to have to come back to this stack and reach argument: reach between two frames with different stack are not the same if you want to get the handlebar at the same hieght on two bikes because your head tube angle is not 90 degrees. because the fork is at an angle pointing back toward the rider, you lose reach for every unit of height created by frame stack and headset spacers.

stack difference between my current 54cm Vaya and a 50cm DCD is 44mm. a little basic trig shows that adding 44mm of spacers on top of a 50cm DCD would be a net loss of about 14mm of reach (in addition to the aesthetic crime it would be to ride with that kind of spacer stack).

the effective reach, when you take frame stack and HA into account, of the 54cm Soma frame is extrapolated (?) to 380mm. add a 80mm stem to that and you have an effective reach of 460mm... which is about what I have now.

going by reach + stem, ETT, or reach alone would have put me on a frame that is much too small because it does not take stack into account.