dsrjohn

I'm 5'10" - is it better to get the 58cm or 56cm IRO Rob Roy frame? Proportionally speaking, I have a slightly shorter torso than legs but longish arms. I prefer a slightly more upright ride rather than hunched low over the handlebars. Suggestions or either could work?

john

SingleSpeeDemon

Frame size is a difficult subject. We have 6' riders on 54cm and 5'7 rides on 56cm. Everyone has on opinion. I would give my measurements to Tony and make sure you understand the dimensions of the Rob Roy. I'm sure Tony can help.

warrantchief

IRO measures frames in quite possibly the most ******** manner ever. Check the geometry on the webpage and go by top tube length. If you're comparing to another bike, make sure you confirm that both are center to center.

My IRO angus "measures" 61cm according to IRO, it's a 59 or 58cm frame from any other manufacturer.

If you want an upright ride, get risers, don't get a frame thats too small.

TNCLR

56. 58 would be HUGE for you.

sk8.johnson

looking at the table at the bottom of this page: https://www.irocycle.com/id24.html

I'd say go for the 58cm.

but those dimensions seem strange. does that frame have compact geometry?

dirtyphotons

i ride a 58 rob roy.

i'm 5'8" with relatively longish legs and ride the size they call a 58. it is actually 54 c-t-c with 32" standover. i don't know why they do this, but they measure to the top of the seatpost clamp (not the top of the top tube) so this measurement could neither be called c-t-c or c-t-t. i'd recommend you go by the c-t-c measurement, the "size" is irrelevant.

i love mine, by the way.

TNCLR

Are you guys looking at the top tube length as well? There is more to sizing than just standover. a 58cm frame has a 56cm top tube. The 56 has a 54cm top tube. I'm 5'10" and found 54cm to be the sweet spot (for me). I'm a fan of erring on the side of smaller frames though. To each his own I suppose.

barba

As much as IRO seems like a good company, this always seems like a problem to me. Frame size guesses by height is a dicey matter on a mail order bike you can't test ride. I would use one of those online fit calculators and try to match the result to an IRO frame. Any advice you get here will be speculative without knowing your measurements.

dirtyphotons

good point. i've got a slightly shorter stem on mine (to compensate for a top tube that's a cm or so longer than my ideal geometry). i've always had better experiences with lots of seatpost showing than with extremely short or extremely long stems.

the headtube is pretty slack as well, so with a few spacers that brings the bars back towards me a bit more.

agreed about erring on the side of small though.

dsrjohn

The only bike size site I have found is to determine ideal standover - mine came out at a 57cm frame but frame sizes vary. How do I determine ideal top-tube length? Especially if one has longish arms? And what about a shortish torso? That will affect the ideal top tube length as well? Any sites that you can recommend?

john

dsrjohn

I forgot to add, I haven't tried a Rob Roy (nor is there one available around here) frame but did sit on a Kona Paddy Wagon at a local bike shop. I liked their "56 cm" bike. Here is a link with the dimensions of the Paddy Wagon:
https://www.konabikes.co.uk/2k7bikes/paddy_wagon_2k7.php

Here are the dimensions of the Rob Roy:
https://www.irocycle.com/id11.html

Seeing that a 56cm Paddy Wagon felt good, would the 56cm or 58cm Rob Roy come closest to the 56cm Paddy Wagon? I should have put this info in the first post...

john

warrantchief

Rob roy in 58cm is the right size. Both have 56cm top tubes. Kona doesn't publish the seat tube length, for some reason, but even if it's different a seat post is more adjustable than a stem.

dirtyphotons

the problem in comparing geometries (at least in terms of tube lengths) is that the paddy wagon has a sloping top tube where the rob roy has an almost horizontal (i'd say about a half centimeter drop) top tube. since the paddy wagon's tt is sloping, and it comes in at 56.1cm, i'm guessing it's a little bit longer of a bike than the rob roy.

that being said, some manufacturers release an "effective" top tube length which roughly translates to the length the top tube would be if it were horizontal.

in terms of which would be more similar (and anybody please correct me if i'm wrong here) i think the 58 (which has a 54 c-t-c seat tube and a 56 top tube) rob roy would match more closely than the 56 (which has a 52 c-t-c seat tube and a 55 top tube).

unfortunately, this is all largely academic. i've never calculated my fit nor been fitted by a shop, i've just had the good fortune to ride lots of different kinds of bikes and figure out what i like based on that.

on the off chance that you find yourself in the dc area you're welcome to take mine for a spin. best of luck.

TNCLR

Read it again chief. The 58 has a 56cm top tube while the 56 has 55cm top tube.

Wowbagger

https://www.competitivecyclist.com/za...LCULATOR_INTRO

That website does top-tube length as well. And yes of course arm and torson length influence your ideal top tube length.

dsrjohn

Thanks everyone for all your input. It really helped, espcially that last post withthe fit calculator.