Help me "Riv" my bike fit, Please!

[Davey Two Shoes]

Hi Everyone,

I'm building up a Sam Hillborne and this is my first Riv build. I'm not sure where to start with stack and reach. Coming from your typical roadie fit I'm not sure how much shorter to make my reach and taller to make my stack in order to get that coveted Rivendell riding position. I'm trying to get this right with as few stem purchases and bar wrap jobs as possible! Are there any general rules of thumb here? This build will be a drop bar build.

My handlebar (not frame) XY position is as follows:

Stack 626mm

Reach 498mm

Appreciate any help you can give me!

For reference, my Fred Sled: (excuse the flat tires)

[Matti]

I am also building up a new Sam.   I am planning to use a quill-to-threadless riser ( https://www.somafabshop.com/shop/soma-high-rider-xl-quill-28-6-22-2-290mm-4984?category=983#attr=2406) so that I can experiment with different stem lengths using a few used threadless stems in varied lengths to dial in the geometry for comfort.  Since these stems have removable faceplates, it should be relatively painless to play around with things without removing brakes and bar end shifters.  Once I get the geometry figured out, I'd like end up with a Nitto Technomic or Tallux.

[Jason Fuller]

The unique thing about typical Riv builds is they're surprisingly flexible on stack and reach - of course, stack is easily adjusted by the long quill stems to suit your fancy, but also the reach becomes much less sensitive if you run a swept bar like an Albatross because there's enough fore-aft room that your hands just naturally find a comfortable position along the bar. 

For a Sam, my suggestion is to run the Albatross bar and an 11cm Tallux stem and see how it feels. This bar / stem puts the hands in a pretty natural position for the Sam's ETT and steers nice.  Quite likely, your natural hand position will land in the good zone with this setup

[J G]

How is the fit on your current bike and do you have any wrist issues after long rides or all feels great, always?  Just want to make sure your weight distribution is good on current ride as I worry a touch about whether your saddle setback and seat angle are putting weight on your wrists.

If you are pretty happy with fit now, but just want to try and get a little more Riv fit wise on the Sam, I would encourage you to reduce your saddle to bar drop to about 1" and bring your saddle tip to bar center back about 1" as well and you might find that as a good start for a more upright position.  I also really like short and shallow bars but maybe you are more flexible than I am.  If you are not using your drops much now, the reduction in saddle to bar drop and a shallow bar will make the drops for more available.

YMMV.  Just where I would start if I was coming from the bike you are riding and wanted a different fit, but not too extreme of a change to start.

[John Hawrylak]

No offense, but your current bike could be a Riv poster child for the 'racer look' vs the 'Riv look', bars much lower than saddle vs bars at or above saddle height (<= 2" above).

The Sam uses a quill stem, so you can adjust the quill height.  To replicate the fit on your existing bike, get a quill stem of approximately 150mm quill length and a stem length of the your current threadless stem adjusted for the increased seat tube setback of the Sam vs current frame 

Saddle Height * (cos(STA current) - cos(STA sam)),   Probaly  3cm based on a 71cm SH and a 74° STAcurrent (Sam STA is 71.5°).  

 For a higher bar height, you'll need a quill length of 180mm or 225mm.  Moving the bars up also brings them back by a few mm, use the 

above equation and substitute 'difference in quill length' for 'saddle height'

 Your frame seems to be small or medium, so a 180 or 225mm quill may NOT be able to be inserted into the head tube/steerer tube far enough to get a 'low' bar height.  This has happened to people before, since Riv recommends longer quills, assuming you'll use the longer quill to extend the bar height and stuff it into a short head tube.

 Dont wrap the bars until you are done getting the bars where you want.

John Hawrylak

Woodstown NJ

PS the Seat Tube Setback is greater with the Sam vs current bike, since the Sam STA is smaller (71.5° vs probably 74° on current bike).  This affects the distance from the saddle to bars using Stack and Reach by themselves

[John Hawrylak]

Dave

I sent you PM with an Excel file to help you select the correct stem length

John Hawrylak

Woodstown NJ

On Monday, January 9, 2023 at 9:42:15 AM UTC-5 Davey Two Shoes wrote: