Jim - it will also be easier to get a Riv fit if you just buy one ;)
On Apr 16, 2:59 pm, "Doug Peterson" <dougpn...@cox.net> wrote:
> Jim:
>
> When I bought my Atlantis, Riv suggested I go with 61 and I was confident a
> 58 would fit. 6 years later, I'm perfectly happy with the 58, with 10 cm
> Nitto stem and 175 Sugino cranks. I've had various UJBs, Treks, etc. from
> 56 to 58 and been fine.
>
> I pulled my file and Riv had an Atlantis flyer with some sizing charts.
> There's some overlap in frame sizes. A 58 is listed for PBH 84 to 89 and
> saddle ht of 74 to 79. The 61 is for PBH of 87 to 93 and saddle at 77 to
> 82. On my build sheets I listed PBH at 86 and saddle at 76 (that was on a
> UJB) and I'm 5'11" tall. So I'm slightly taller with my saddle slightly
> lower than you.
>
> Since the largest frame I'd lived with was a 58, I was a bit surprised when
> Riv suggested 61. The sizing chart put me on a 58. The bike came with 35
> mm Pasela tires and it's now on 35 mm Schwalbes which are a bit plumper but
> I still have adequate stand over clearance with both feet on the ground.
> The h'bars (Nitto drops) are up even with the saddle.
>
> Stem is the 10 cm that came stock. I would drop down to 170 cranks were I
> to do it again as the 175s limit clearance off road. 5 mm isn't much extra
> clearance so it's a minor issue. I didn't think thru the BB height issue,
> just order what I'd been using, my bad.
>
> Hope this helps. Assuming your comfortable with your current fit, the key
> is figuring out how to duplicate that fit on another bike. Fortunately,
> you're in middle of sizing bell curve so you've got plenty of room to work
> in.
>
> dougP
>
> -----Original Message-----
> From: rbw-owners-bunch@googlegroups.com
>
> [mailto:rbw-owners-bu...@googlegroups.com] On Behalf Of jim g
> Sent: Thursday, April 16, 2009 11:50 AM
> To: rbw-owners-bunch@googlegroups.com
> Subject: [RBW] Riv Bike-Fit/Sizing Method Questions
>
> I'm trying to figure out the right frame size for a possible next
> bike-project. I want a "Rivendell fit" with bars about level with
> saddle, and somewhere around "a fistful" of seatpost showing. I'm
> about 5ft 10in tall; PBH is 86cm in bare feet, 87cm in my SPD bike
> shoes; preferred crank length is 172.5 or 175mm. Saddle height on
> current bike is comfortable at ~77cm.
>
> I'm reading Riv's fit guidelines
> athttp://www.rivbike.com/article/bike_fit/choosing_a_frame_sizeand am
> finding some confusing points. Starting from "How to Size any Bike,
> Including Ours", they use an example PBH of 85cm, and suggest that a
> corresponding saddle height is 75cm -- or 10cm less than the PBH. So
> far, I'm OK with that: my saddle height is around 10cm less than my
> PBH (especially accounting for my shoes).
>
> Next Riv suggests that a good bike size is saddle height minus 15cm.
> In my case, that's 86cm - 15cm = 61cm, or accounting for shoes, 87cm -
> 15cm = 62cm. Again, I'm in agreement with that: Most non-Riv 62cm
> frames I've straddled have been a bit "snug" but not overly so in
> standover height -- that is to say, the top tube touches but not
> dangerously so. And I could definitely fit on a 60cm frame, but I'd
> need a taller quill stem, or some extra spacers in a threadless setup,
> and of course there'd be more seatpost showing.
>
> Now, on to the next section on Riv's page: "Sizing Rivendells (the
> bikes we design)".... If you look at the frame-size chart they
> provide, for 86-87cm PBH measurements, they recommend 59-61cm frame
> sizes! Here's where I'm confused -- most Riv frames have a lower BB
> than a typical/average frame, up to 1cm lower. Most of Riv's sizing
> theory says something like "you can straddle a bigger one-of-our-bikes
> than one-of-theirs", so I've always thought that a correct Riv size
> would be 1cm larger than a "typical" frame size (and by typical frame
> I mean 1980's UJB steel frame or similar). Taking the previous frame
> size result of 61-62cm, that'd put me on a 62-63cm Riv. HOWEVER that
> chart points to a 59-61cm Riv frame for my body size -- which is
> SMALLER than the first recommended "normal" size, and frankly sounds
> too small!
>
> For example, the 61cm AHH has an 8cm BB drop and standover is just
> under 87cm -- that'd maybe be slightly too big for me (no clearance,
> since it's the same as my shod PBH). I guess the "Riv Size = usual
> size + 1cm" formula doesn't directly apply to the AHH because the
> larger tires cancel out the added BB drop? The 59cm AHH frame has
> 85cm of standover, which seems about right (about an inch of PB/TT
> clearance)...BUT a friend of mine rides this size, and he's always
> been on shorter/smaller bikes than me...so a 59cm sounds too small
> somehow.
>
> In contrast, the 61cm Atlantis has a standover of 85cm, so that'd fit
> me with the right clearance. Why that frame would fit but the
> same-size AHH wouldn't, isn't clear to me -- looking at their
> geometries, both have the same BB drop, similar size tires, the same
> seat-tube angle, and both have slightly-sloping top tubes.
>
> The Legolas frame is more typical since it has a standard 70mm BB
> drop. (Ignoring the fact that it's intended as a CX bike, which might
> indicate more-than-usual SO clearance) I could ride a 62cm size since
> its standover is 86.2, but clearance might be tight. The next smaller
> size is 59cm with 84.3cm standover.
>
> The Quickbeam frame is also fairly "normal" with a 73mm BB drop. The
> 62cm frame size has a standover of nearly 87cm (too big), but the 60cm
> size's SO is about 85cm.
>
> Now let's compare those data points with a fairly typical non-Riv
> steel frame: A Surly Pacer (level top tube, 72.5-degree seat tube
> angle, 72mm BB drop). The 62cm frame size has a standover measurement
> of just under 86cm, and the 60cm size's SO is 84cm (based on 700x25mm
> tires). Riv's Rambouillet frame has similar values at the same sizes.
>
> Overall, it sounds like I could ride a bigger Pacer frame than most
> Rivendell frames -- which seems utterly counter-intuitive to me, since
> most Riv frames have lower BBs!
>
> If anyone has a PBH of 86-87cm, I'd be very interested to hear what
> size frame(s) you've chosen (both Riv and non-Riv) and why.
>
> Thanks!
> -Jim G
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