I am 176cm and 78cm inseam.

Ride a small

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Espen Wagener
Kongsberg, Norway

http://www.espenwagener.blogspot.com

I am 6' and 33 inseam and ride a large if it helps any.

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you might note the write-up of that bike i posted yesterday on the front page.

about the size of the plasma in size small. in height, it's within a very few millimeters of exactly the same as the cervelo p3c in size 56cm, or the specialized new transition s works in size M, the Kuota Queen K in size 56cm. but it's also like the size S in the giant trinity alliance. so, like the trinity alliance, the small runs a little "big". the plasmas appear "big" in terms of their heights.

of course, what's funny about this sort of sizing is how ridiculously inaccurate it is. the small plasma is almost precisely the same bike, in terms of it's absolute height and length and the new S Works in size medium.

the issue with the plasma is going to be length relative to height. if you take all bikes and normalize them to the same seat angle, the size S in the plasma is the same length as the Queen K in 48cm, trinity alliance in XS, all the felts in size 50cm, and in this size plasma is closer to cervelo size 48cm than its size 51cm. so, the plasma is short in size S, and really in all its sizes.

this is because the plasma is built around a 76 degree seat angle. the shallower angle pulls the head tube back toward the BB. but, the head angles are shallow and this scoots the front wheel axle a bit forward, so there's no huge weight displacement issues.

all in all, the size S is not really that S. if you position yourself in accordance with how i think people ought to fit aboard their tri bikes, the issue is going to be getting low enough, in particular if your plasma is outfitted with profile's T2 aerobars, which set the armrests fairly lofty.

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Dan Empfield
aka Slowman

Ok, I need some help here. Perhaps I am a bit dense but this has never made sense to me. I ride a plasma and love it. As Dan mentioned, It is spec'd with Profile bars. I believe that this must be why it gets such a bad rap about inability to get decent drop. If you ride low, you are going to have to do acouple of things, (remove spacer duh) perhaps swap out to something like vision, or flip your T2s. But why is the geometry so different then? Headtubs for example. It was mentioned that the plasma small is the same size as the p3c 56. The headtube lengths on the plasma small is 110 while the p3c is 125.

I am sure its not as simple as I am making this out to be, but why can you get lower on the p3 than the plasma with a shorter headtube?

BTW I am 6 ft and a 32 inseam, I ride a medium.

t

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"It is spec'd with Profile bars. I believe that this must be why it gets such a bad rap about inability to get decent drop."

i think the other "bad rap" it gets, to the degree it does get a bad rap (does it?), has to do with its XL size, on which there's a huge jump in head tube length, hence a huge jump in overall height. incidentally, i'm not finding the XL on the plasma's size chart anymore. i wonder if they may be reworking that size. i don't know.

"why is the geometry so different then? Headtubs for example. It was mentioned that the plasma small is the same size as the p3c 56. The headtube lengths on the plasma small is 110 while the p3c is 125."

about half this 15mm difference is sucked up in BB drop. the cervelo's BB sits about three-quarters of a centimeter higher relative to the wheelbase centerline. so, when you ride a cervelo you're hiked up toward the head tube top, making the bike effectively smaller for you, as regards how the bike will fit. as to the other three-quarters of a cm, i'd have to do some nosing around and see what accounts for it. i largely rely on the numbers the bike companies give me, and i investigate further if the numbers obviously don't make sense to me.

i don't have any beef with the plasma's geometry. it's just that it's a 76 degree bike, and if you ride it at 76 degrees that's great. if you ride it at 79 or 80 degrees, then the bike is that amount short, and you have to put a longer stem on it to compensate. that's not saying it's good or bad, it's a statement of fact. it's just numbers.

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Dan Empfield
aka Slowman

I'm almost exactly your same dimensions and ride a med Plasma, which fits perfectly.

I think it will be the fork length difference - Scott have a slightly longer than typical axle-crown measurement.

Thank you Dan for the detailed reply. So based on the below particular paragraph that you wrote..

"the issue with the plasma is going to be length relative to height. if you take all bikes and normalize them to the same seat angle, the size S in the plasma is the same length as the Queen K in 48cm, trinity alliance in XS, all the felts in size 50cm, and in this size plasma is closer to cervelo size 48cm than its size 51cm. so, the plasma is short in size S, and really in all its sizes."

It looks like i would be better on a Plasma Medium?

U see i have ridden a QR Lucero Medium (TT 53cm, STA 77) and Planet X Medium (TT 52.7cm, STA 76) and they both fit pretty good. I had to use a 2-cm spacer on top of the headtube. So based on what you wrote here...it looks like the Plasma Medium would fit me a little better than the Small? I know it is difficult to decide without hopping on the bike but the issue is that most of the bike shops dont stock both the Medium and a Small Plasma.

thanx again for ur help.
gary

here's the thing about those two sizes. they are very close together. you're talking about 12 millimeters in difference both in the height and the length. in other words, the small is just over a centimeter shorter in height than the medium, and just over a centimeter shorter in length. so, yes, fine, go with the medium, you'll get a little extra length, and if the small is not too tall it's almost impossible that the medium will be.

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Dan Empfield
aka Slowman

BTW I am 6 ft and a 32 inseam, I ride a medium.
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What stem length do u use on ur medium Plasma?

Would you advise any changes in my position Dan?
I am thinking of an adjustable stem to get lower...?

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Espen Wagener
Kongsberg, Norway

http://www.espenwagener.blogspot.com

it's hard to know without a picture more in profile (from the side). it looks like a pretty good position to me, but that's off this fairly limited data the pic affords me.

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Dan Empfield
aka Slowman

my 2 cents ,rode a 55 cervelo p3 dropped down to a 54 scott and love it 31.5 inseam best bike in the world.....jimmy

I’ll looking at purchasing a 2016 Scott plasma team edition. I’m 6’4”, 36” inseam. I’m assuming I’ll require the XL frame? I’m currently riding a 2012 CERVELO p3 58cm but find it slightly cramped.

I'm 6'2", saddle height of 822 mm, Pad X/Y of 515/678, and I ride a Plasma size large. For me the stack of the Plasma works well without needing to be slammed or use tons of spacers, and I still have some room to play with reach. Given your height and inseam I think you're right to be considering the XL.

For greater context I posted a few pics of my position on the bike to Dan's saddle height experiment thread.

Thanks for the help

I used to have a medium and it fit perfectly. I’m 6’ and 87.9 inseam and used a 100mm stem.