In between Homer sizes — please help!

[Brian Choy]

Hi All, I need some help figuring out if I should size up or down with a 47.5cm or 51cm Homer because I seem to be in between sizes. 

For reference, I have a 78cm PBH (standing at 168cm/5’6 height) and have a 67cm-ish saddle height. I normally ride a 50cm Surly Midnight Special with drop bars, but I plan on keeping swept back or alt bars on the Homer.

According to Riv’s site, they recommend a 47.5cm for minimum PBH of 76cm and a 51cm for minimum PBH of 80cm. The stand over of the 51 is 78.5cm, but I’m not as concerned with stand over as I am with feeling comfortable while riding. 

I was able to test ride a Roaduno (with very similar geo as I understand) in 47.5cm and 51cm. The 47.5 had a setback seat post and felt a little small / cramped with the very swept back bars, or maybe I’m just not used to sitting so straight up. The 51 felt much closer to my Surly, which I found to be roomier and more comfortable, but I’m concerned that getting a larger frame may hinder me from achieving a correct bike fit, even if I went with a straight seat post. I mainly see Rivs with set back seat posts and it makes me wonder if that’s the ideal way to ride them. I can’t tell if the 47.5cm is sized right for me and that I’m just used to a bigger bike, or if the bigger bike is what I should be on.

Any insight is appreciated. Hoping to grab a Homer when Riv releases their new batch.

Thanks in advance!

[Jason Fuller]

That's a tough one indeed!  I am inclined to believe the 51 is the correct choice if you're running upright bars and are okay with poor standover.  I ride a 51 Hillborne with a 71.5cm saddle height at 5'8" and I'm at the top end of the fit range I'd say with a swept bar.  Your experience suggests the same it seems.  

The set back posts play well with Brooks saddles as their rails tend to put the saddle further forward than most, that's my theory why the set back is so common. The other factor is that slacker effective seatpost angle is needed when sitting upright. I don't believe you'll have any trouble getting the fit right with the 51, provided you're running a Rivvy bar like the Choco or similar.  In fact you'll probably still find you want a 10-11cm stem, but could always go a little shorter if you had to. 

[Brian Choy]

Jason, that's all incredibly helpful and helps make sense of so many questions I've had.

Thanks so much!!

[J S]

47.5 for sure or you will have a bike that is too big for you. Been there and was never happy with the too large bikes.

[J S]

I should add that my Saluki is a 54cm (51cm by today's standards) and my Hillborne is a 51cm). I have a tad of room, not much. My saddle height is 76.5 I believe, I can measure. My perfect standover which nobody really talks about here is about 30" which puts me just a bit under the bikes TT from the ground height. Height means little as I have watched my height diminish as I age but my standover stays the same, it really is about PBH and standover. If you do not mind a bike that will give you little to no standover space then go up. I also found I could have high bars with a Nitto Technomic XL I think it is called.I gave me the height I needed for my Saluki that one previous owner had cut the steerer tube quite short but all is good with that stem.

Good luck, I always wanted a larger bike for the look but in reality I am much happier with a bike that fits and gives me some clearance. My first Saluki that I bought new was a 56cm, too large and I waited close or over 20 years to find a 54cm. 

[Garth]

A 50cm Midnight Special has a 73.5d seat tube angle, whereas the Homer is 71.5d. When calculating the overal saddle-to-bar reach that has to be accounted for as you will otherwise you may be miscalculating your reach. I've had this saved from a previous Riv Reader that may help you in regards to fitting. 

In my experience the saddle position fore-aft need not change when changing bodily profile upwards. More or less, I now question everything I ever read about bike fitting as everyone is unique, formulas don't apply to anyone. Even the attached Reader article, it's to better understand saddle to bar relations and how that varies from frame angle differences between bikes, not to follow any certain way of applying it to your bikes. In the real world we'd all like to be able have two or more bikes setup exaclty as we like before we buy either of them. 

 

[Patrick Moore]

Garth: When I try to “Preview” the PDF I get an error message; and when I download it and try to open it as a PDF I get a “Corrupted” message.

Is it me? Might the file be corrupted? In any event, I’d like to read it, so if you can make it universally open-able and readable, I’d be very grateful.

Patrick Moore, who also is “rule-of-fit” skeptical, in ABQ, NM.

[Roberta]

I wasn’t able to preview it, but I was able to download it but the only way to see it was to use “open with acrobat “. 

I sent my copy to Patrick. Hopefully that works for him.

[Garth]

I can't say why the pdf doesn't just open in another browser window as it does for me. I'm using desktop software, for reference. Anyways, the entire reader can be viewed/downloaded from here : https://notfine.com/rivreader/RR13.pdf . The part on fit is pages 19-22, so if you wish to save only thoose pages you can select tp print it, which opens the print dialogue, and choose "save as pdf", and input thepages as 19-22. Again, this is a desktop browser, chrome or mozilla based. Nevertheless, If you see the images inline here I posted the saved and converted to jpg images of just the relevant pages 19-22. 

[Dorothy C]

The full geo chart says 47.5 Homer fits 76 - 80 pbh and the 51 fits 80 to 83.5 pbh. So I would say that puts you solidly on the 47.5. 

https://cdn.shopify.com/s/files/1/1403/7343/files/RBW_Bicycle_Geometries_-_March_2025.pdf?v=1742249878

[Dorothy C]

In case you aren’t already thoroughly confused ;) Riv say that their frame size + 13cm = minimum saddle height recommendation

On Sunday, April 27, 2025 at 7:06:10 AM UTC-7 Matt B. wrote:

I would go off of your saddle height vs. your PBH measurement which is difficult to get right, with measurement errors skewing low.   Your preferred saddle height, if adjusted based on experience riding or rule of thumb (such as leg fully extended with heel on pedal), is typically PBH minus 15cm, which would indicate that your true PBH is probably more like 82cm.  That would put you on a size 51 easily.  Different strokes for different folks but personally I'd much rather have a frame that fits or is on the roomier side vs. one that is too small.

Matt

[Roberta]

When I bought my 2019 Homer (different geometry), I was in the same predicament as you, on the cusp of sizing and actually at the upper range for the smaller 51 cm size. However, I bought the bigger size, 54.5 cm, because somebody within driving distance was selling a nicely built 54.5 cm Homer and I could get it right away.   Stand over is tight when standing, but the size for riding bike is perfect for me.  I always ride that Bike with sneakers and never with thin soled shoes , and it is my favorite bicycle. 

You , yourself , said the smaller size felt too small and the larger size felt comfortable.   You can make adjustments in the handlebar choice and stem length.  Remember also tire size can raise or lower standover height, so you do have a little control there too.   I am not a Riv bike expert at all, but I’ve ridden enough Rivs, some only for test rides , to know that, for me, I don’t like to be cramped on a bike. 

If your PBH is 68 cm and your height is 5‘6“ that also tells me you have shorter legs with longer torso,  and would need the extra reach that the larger Bike can give you. I think you’d be better off with the larger size. 

Perhaps this could help: https://bikeinsights.com

Roberta

On Thursday, April 24, 2025 at 2:45:15 PM UTC-4 bch...@gmail.com wrote:

[Laing Conley]

Depends on if you have relatively long legs or a relatively long torso. 

Relatively long legs - go with the smaller size to get the shorter top tube.

Relatively long torso - go with the larger size to get the longer top tube. 

Normal leg/torso length relationship, back to the tossup - larger frame for higher bars, smaller frame for lower bars or lighter weight. 

Laing

Delray Beach FL

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[Brian Choy]

Everyone -- thanks for a helpful and intriguing conversation on Homer sizing! I went ahead and committed to a 51cm instead of a 47.5cm despite Riv's PBH charts. I also consulted Will and James at Riv on this topic and they both thought I should go for the 51, ignoring limited standover height to prioritizing comfort while riding. I'm going to trust my gut on this based on my initial reactions to the 47.5 vs 51 Roadunos.

Garth -- Very interesting read. Thanks for sharing the PDF!

Matt -- I thought saddle height was estimated at PBH minus 10cm? My PBH is 78cm and my saddle height is about 67cm, both measurements taken by my bike fitter.

Dorothy -- Me falling right on the 47.5 according to the Riv chart vs my personal experience on the Roaduno is what's confusing me. Riv is confident that their charts are accurate, but riding a 47.5 felt like I was on a kid's sized bike. Now that I know frame size + 13cm = minimum recommended saddle height, a 51 should work for me because 51 + 13 = 64, and my saddle height is roughly 67cm. Thanks for that!

Roberta -- I also don't like to be cramped on a bike. If anything, my Midnight Special has accustomed me to enjoying a bit more of reach. Being able to stretch out a bit on longer rides is really helpful. I'm 5'6 with a 78cm PBH (67ish cm saddle height); I think I lean slightly to having a longer torso and shorter legs.

Laing -- Thanks for the insight! Toss up indeed, which did not make this decision any easier for me lol.

[Garth]

https://bikeinsights.com/compare?geometries=5fa0407f80585a00179be294,6528638e2a3463001aa70407,

I used the formula from the reader(page 19) to calculate the seat tube setback based on the seat tube angles of 73.5 and 71.5. It's a 2cm difference. So if the OP wanted a saddle in the same position as the Surly on say a 51 Homer, that  2cm is lost as less overall saddle to bar reach to begin with. Couple that with the 1.8cm inherent less reach of the Homer and the OP or reader of this can draw their own conclusion.

On Sunday, April 27, 2025 at 1:11:25 PM UTC-4 lconley wrote:

[Roberta]

Congratulations, and I think you’ll be very happy. 

I’ve had four Rivendell’s – – an Appaloosa (sold), platypus, Betty Foy, and A. Homer Hilson, which is my most favorite bike of the group, although there’s not a bad one in the group.  It’s Light,  lively, responsive.

I’m looking forward to seeing pictures and getting a ride report. I know you’ll be delighted.

Roberta

[J S]

For some reason I did not see that your saddle height is 66cm, I thought you had 64 or something in a post. At 66 I would go with the 51cm, I have a 67.5 saddle height and ride a 51 Hillborne with a tad of room.  Enjoy

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[Matt B.]

Ah you are right regarding PBH vs. saddle height being about 10cm - still, I think you made the right choice going with the 51, especially if you spoke to staff about it, they definitely know best after working with thousands of riders.   Anyway good luck with the new bike!

Matt

On Sunday, April 27, 2025 at 8:40:59 PM UTC-4 bch...@gmail.com wrote:

[Victor Hanson]

You need to figure out your stem cl height  together with dimension from the ground (with tires inflated) to the cl of the seat rails,    With those two dimensions and the top length the rest is how flexible your are- right this affects stem selection together with bar choice.  Thats it.

VTW

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Schmier Industrial Properties

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