Ridley Helium sizing help

[Dwn2Sk8]

Hi all,
I am looking for some help from those of you who own/have owned a Ridley. I am in the market for a Helium, but am not sure if I should go with a size S or XS. I am 5'8" with a 32 inch inseam. My other bicycles include a Look 595 in size M and a BMC SLC01 Pro Machine in a size 53, both of which fit me well. From what I can tell by comparing the geometry, size S in the Helium should work but I've also read that Ridley's frame sizes don't always match the listed geometry numbers. If I can make a XS work, I can get a good deal on a Helium SL.
Any help would be appreciated.

-Rich

[ultraman6970]

Im lit taller than you but your legs looks like longer than mine, I used a damocles and I went small... Ridley low and long.

If you are like 72 cm height seatpost, like 11cm stem the xs IMO will be really too small.

My opinion ok?

[Dwn2Sk8]

Im lit taller than you but your legs looks like longer than mine, I used a damocles and I went small... Ridley low and long.

If you are like 72 cm height seatpost, like 11cm stem the xs IMO will be really too small.

My opinion ok?

Thanks for the reply Ultraman!
I am currently running a 10cm stem with a 1cm spacer on my 595. My seatpost height is indeed 72cm.
Stack and height on my 595 is 55.1cm and 38.4cm respectively.
Stack and reach on a small Helium is 54.5cm and 38.5cm respectively and on an XS it is 53 and 37.5.
Looks like the small would fit most like my 595, correct? Would the XS require too many spacers under the stem for a proper fit? I really don't want to go any more than 1cm worth of spacers.
Thanks again!

[kramnnim]

I have a Helium SL in Small and absolutely love it.

Have a Large 586 and used to have a M 585...

[kramnnim]

The Ridley frame should match the listed geometry, it just does not compare well to "normal" sizing...the Small is more like a Medium in other brands, perhaps a little bigger.

[ultraman6970]

To figure it out the spacers you have to measure the front tube, is the only way to know IMO. U arent that far (5 mm or so) from the other bikes you have, sure the size of the front tube is in the geometry tables aswell... measure the front tubes and see how it goes, probably is close enough to your other bikes.

[Dwn2Sk8]

To figure it out the spacers you have to measure the front tube, is the only way to know IMO. U arent that far (5 mm or so) from the other bikes you have, sure the size of the front tube is in the geometry tables aswell... measure the front tubes and see how it goes, probably is close enough to your other bikes.
Head tube is 145mm on the small Ridley and 130 on the XS.
My Look is 148mm.

[kramnnim]

Yeah, you'd want the Small, unless you get the XS and a 110mm stem and lower your bars...

[ultraman6970]

3 mm is close enough, reach and other stuff is between what you already use.

[ls1togo]

I, too, are a little taller but with shorter legs...my 2012 Helium is a small and fits well. It's light, fast and...a "toss-up" with my Serotta Ti in comfort..

[ahumblecycler]

I am 5'10.5" and would pick a small. For reference, I pick 54cm in Cannondale and Specialized. The tricky part about Ridley sizing is the 66cm bottom bracket drop, which makes me skeptical of Ridley's reach/stack figures (not that other manufacturers are great either; I have found Focus to be the only one to be accurate in person with a tape measure).

My rule of thumb is that it is easier to make a smaller bike to fit compared to a larger (again, just my rule).

[ultraman6970]

I do have to agree with humblecycler, when the frames are tad big is really hard to get them right because they dont work as intended, usually the symptoms are weird handling or that the bike feels like dead (but worked for every body else you know).

unless it is super small (thing we have seen in the forums) a frame tad smaller is a lot easier to fit. Smaller but not like 2 sizes down...

When you get older frames start feeling bigger, sucks :D

[parallelfish]

The tricky part about Ridley sizing is the 66cm bottom bracket drop, which makes me skeptical of Ridley's reach/stack figures

I don't follow the reasoning here.

[ultraman6970]

If the BB is lower the stack and reach changes a little bit, making the bike tad shorter if im not mistaken, but we are talking about millimeters of difference. I never measure geometry to the T more than TT-ST and FT, but looks like some people does :D

[parallelfish]

If the BB is lower the stack and reach changes a little bit, making the bike tad shorter if im not mistaken, but we are talking about millimeters of difference. I never measure geometry to the T more than TT-ST and FT, but looks like some people does :D

How? Given that stack and reach are measured in relation to the center of the bottom bracket, they do not care if the BB is high or low. The overall height of the bike will be effected, but not stack and reach.