Soma frames and geometry - longish top tube?

[tylercheung]

Was looking at some of the Soma fab frames...the Stanyan and Pescadero, and the usual Smoothie/Smoothie ES are supposedly nice frames for the money. I am thinking of building up a smaller frame for my girlfriend also for some smaller visitors if we want to do day biking trips. However, I noticed the geometry seems to favor longer effective top tube length. For example...I usually ride a "53" or a "54" frame and have a TT of about 53.5 ish cm - 54 cm, but the Soma frame size for a "54" (presumably seat tube) goes to about 55-55.5 cm, while the 51 has a TT length of 53.5 mm. For example:

http://www.somafab.com/archives/product/es#tabs-568-0-3

Am I missing something? Or do these frames generally run longish on the top tube?

[panache_mode]

I recently built up a soma and I sized down because of the top tube just like you had mentioned.

Not sure on why exactly they have the trend of longer too tubes but it could be a built in feature for a more relaxed style geo.

The some smoothie has a longer head tube some even with the stem slammed it isn't extremely aggressive.


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[eddief]

the seat tube will reach your butt by raising the saddle on the seatpost.

[owly]

They do run long.

After looking at a gazillion frame pics, I've learned to spot the long ones looking at the triangle shape.

[easysmile]

All-City, too, seems to favor longish TT's.

They require more flexibility from the rider to be comfortable in them, but the reward is better aerodynamics, etc.

[Macadamia]

Yeah, I don't get their philosophy with sizing. I have a 52 Double Cross, that has a 55.6cm top tube. Other than that it has a tiny headtube, and I get toe overlap, indicating to me that I bought a size too small.

But if I'd bought a 54 of that frame, it would have a 56.7cm toptube, which is longer than my previous 56cm frame I was trying to get away from.

Are they meant to be run with a bunch of spacers, a short stem and wide bars? Why?

[Stevemikesteve]

Yeah, I don't get their philosophy with sizing. I have a 52 Double Cross, that has a 55.6cm top tube. Other than that it has a tiny headtube, and I get toe overlap, indicating to me that I bought a size too small.

But if I'd bought a 54 of that frame, it would have a 56.7cm toptube, which is longer than my previous 56cm frame I was trying to get away from.

Are they meant to be run with a bunch of spacers, a short stem and wide bars? Why?

Bar height was challenging. Recently gave up on my 54 double cross disc, just dismantled it. Sized it from top tube as I'm usually about a 56 or 57ish. Tried to make it work for a while even with a pro-fit thrown in along the way. The short head tubes on those are a head scratcher, too many spacers to get the bar height decent. My first experience with what I guess is modern cross geo. Good quality, a nice ride, seems like decent steel but lesson learned. Felt like I could have potentially gone up 2 sizes to what they label as a 58.

[ColonelJLloyd]

the seat tube will reach your butt by raising the saddle on the seatpost.

While you can achieve your contact points by long seat posts and super short stems it's sub optimal at best. Soma's reach to stack ratio is often more than that of race frames. Their geo is surely great for some folks, but the TTs seem long for the roles they market some of those frames towards.

[tylercheung]

the other concern is as I am building a frame for a smaller (5' 5") person; the smallest size, ~ 48", has a 75 deg seat post which seems a tad extremish

[fogrider]

Yeah, I don't get their philosophy with sizing. I have a 52 Double Cross, that has a 55.6cm top tube. Other than that it has a tiny headtube, and I get toe overlap, indicating to me that I bought a size too small.

But if I'd bought a 54 of that frame, it would have a 56.7cm toptube, which is longer than my previous 56cm frame I was trying to get away from.

Are they meant to be run with a bunch of spacers, a short stem and wide bars? Why?

Look at the photos of built up bikes on their website, they use a fair amount of spacers. I know a few guys that are flexible enough to keep the keep their stems low. And by having long top tube, this means the seat tube is shorter, which means a longer seatpost. Some frame designers think a longer seatpost means the bike's ride can be tuned by using a different seatpost.

[Macadamia]

Look at the photos of built up bikes on their website, they use a fair amount of spacers. I know a few guys that are flexible enough to keep the keep their stems low. And by having long top tube, this means the seat tube is shorter, which means a longer seatpost. Some frame designers think a longer seatpost means the bike's ride can be tuned by using a different seatpost.

Ok, that at least sheds some light on the reasoning, doesn't mean I have to like it though!

Personally, I can take or leave the "slam that stem" mentality, but I really like the way that longer stems slow down a bike's handling, and that probably disqualifies Soma from future consideration. Maybe I just need to do more core work to ride my casual steel cx bike...

[eBAUMANN]

yes, definitely run long, and small in the head tube.

at least for their CX frames...which is all ive ever considered buying.

same with surly cx geo...weirdly small head tubes for frame size.

IMO.

[jruhlen1980]

yes, definitely run long, and small in the head tube.

at least for their CX frames...which is all ive ever considered buying.

same with surly cx geo...weirdly small head tubes for frame size.

IMO.

Not to hijack but I have a question about the surly cross check and sizing. I normally ride a 56 top tube with a 90mm stem, I'm 5'11 with a 33" inseam. The cross check geometry shows that the 54 has a 56 (ish) top tube.

But I've ridden 54s in the past and I need a mile of seat post and run into pretty bad toe overlap.

So any other 5'11 guys out there with experience with the CC or doublecross have problems with those things?

[eBAUMANN]

Not to hijack but I have a question about the surly cross check and sizing. I normally ride a 56 top tube with a 90mm stem, I'm 5'11 with a 33" inseam. The cross check geometry shows that the 54 has a 56 (ish) top tube.

But I've ridden 54s in the past and I need a mile of seat post and run into pretty bad toe overlap.

So any other 5'11 guys out there with experience with the CC or doublecross have problems with those things?

you can figure out how much seatpost youll have visible my measuring your current saddle height and then mapping that onto the new frame geo.

toe overlap will depend on the HTA/fork rake/tt length/tire size/fenders/foot size...so yea, lots of variables there.

[Stevemikesteve]

Not to hijack but I have a question about the surly cross check and sizing. I normally ride a 56 top tube with a 90mm stem, I'm 5'11 with a 33" inseam. The cross check geometry shows that the 54 has a 56 (ish) top tube.

But I've ridden 54s in the past and I need a mile of seat post and run into pretty bad toe overlap.

So any other 5'11 guys out there with experience with the CC or doublecross have problems with those things?

Hey, other post above. I'm a lanky 5'10, actually currently running my backup bike as main ride, a 56 Miyata 1000lt with a 90 stem. It works fine. It's of course an 80's frame, level top tube, 56 square geo. You've got an inch height on me so the 54 Cross Check could be a similar experience for you. It would be worth comparing the head tube length to the double cross in order to determine how much you can get the bars up to where you need them relative to shortish seat tube; unless you want to 1) Run a bunch of spacers if you're someone who likes bar height close to saddle height or 2) Ride hunched over with minimal spacers and a ton of seatpost, skip the Double Cross, doesn't really sound like you're onto that one anyway. Just another 2 cents... Good luck!

[jruhlen1980]

Hey, other post above. I'm a lanky 5'10, actually currently running my backup bike as main ride, a 56 Miyata 1000lt with a 90 stem. It works fine. It's of course an 80's frame, level top tube, 56 square geo. You've got an inch height on me so the 54 Cross Check could be a similar experience for you. It would be worth comparing the head tube length to the double cross in order to determine how much you can get the bars up to where you need them relative to shortish seat tube; unless you want to 1) Run a bunch of spacers if you're someone who likes bar height close to saddle height or 2) Ride hunched over with minimal spacers and a ton of seatpost, skip the Double Cross, doesn't really sound like you're onto that one anyway. Just another 2 cents... Good luck!

Thanks. I'm not buying anything yet, but I have some vaguely defined plans to build a CC up as commuter/cargo/bikepacking rig some day. Used frames can be found pretty cheaply sometimes.

[KidWok]

I have long arms and can take a pretty low stem. Even then, my Double Cross Disc needed 2cm of spacers. Yeah...they're definitely long and low. But hey...isn't that what they call Freuler geometry?

http://i27.photobucket.com/albums/c151/TaiLee77/20140817_194008_zpsvlvsa1mf.jpg

Tai

[cachagua]

"Freuler", yeah, let's call it that. Just looks like a well-sized bike to me. If you imagine that's a quill stem instead of a threadless setup, it doesn't look disproportionate at all.

Love that reflective tape, too.

People used to tell me my bike was too small. I told them no, it's a compact frame with a level top tube. Of course not everybody likes their bike that shape, but I think enough people do that Soma's on firm ground.