Sizing advice

makeitso · 2 Weeks Ago

Here's the basic info, I'm 5'9" with a 30.75" biking inseam (via book between legs method) and around 165 lbs. Seems that I'm more short leg, long torso type. I've been to three bike shops and have been quick fit to 17" - 19" bikes and am unsure which bike works better, and I realize that the fit can be changed by moving around the seat and changing the stem which leads me to my question... Should I go after the 17" bike and change to a longer stem or the 19" and possibly shorten the stem? The biggest problem I see on the larger bike is my lack of leg length as most of the 19" bikes have 30"+ standovers.

Here are the bikes I've tried, assume that the seats are all basically in middle position and factory stems. It'll probably be information overload.

17" Spec Rockhopper '09 - I like the body position but I find myself trying to push my backside further back on the bike a cm or so.

19" Rockhopper '10 - Felt a hair stretched out. Has a 31.4" standover so standing over the top tube right in front of the seat the bits touch but there's no pressure with feet flat on the ground.

19" Rockhopper 29er '10 - Definately felt stretched out in the 5 min parking lot ride and it's standover is probably too tall.

17" GF Wahoo '09 - Again felt a little cramped and trying to slide my butt back a little bit. A bit more upright vs the Rockhopper but still a comfortable body position.

17" GF Coriba 29er '09 - Felt more upright vs the Rockhopper but the fitment seemed pretty good.

19" GF Piranha '09 - Didn't really feel stretched out, but just felt like a big bike if that makes sense.

18.5" Trek 4500 - Felt way too upright, almost felt like a comfort bike.

19" Jamis Exile 29er '10 - Position and standover wasn't bad surprisingly but for the price I think the spec is a bit low so I might eliminate this one.

I'm coming from a 15 year old Mongoose steel rigid bike that's an 18" but for whatever reason it's too small (can't get KOP and feeling cramped but don't want to upgrade it). It's also got a bit too much forward lean for my preference. With the mindset of doing singletrack & fireroads should I go after the smaller bike and use stems and saddle position to make it larger or should I go with the larger bike and use a slightly shorter stem?

Thanks in advance as I know I put way too much info down here.

AZ.MTNS · 2 Weeks Ago

Smaller, you can change everything else to make it fit . If you dont have enough stand over room you cant fix that .

shenny88 · 2 Weeks Ago

just from personal research and relatively short term experience i would strongly advice against the 19" frames... small wrecks could result in costly injuries and discomfort, plus stopping on less than perfectly flat surfaces may be a balancing act.... ps, im 5' 8" and ride a 17" and cant even imagine myself on an 18"

Dremer03 · 2 Weeks Ago

Your at the high end of a medium frame and could possibly fit into a large depending on the manufacturer. I ride a Large 18 inch frame and I am 5' 11", the stand over of my Reken is 29.21. I would seek out a 18 inch bike and try that out. Your old 18 inch rigid Mongoose probably feels small because it probably has a high rise quill and riser bars.

jride1078 · 2 Weeks Ago

Thanks. it helps.

makeitso · 2 Weeks Ago

I just went out and measured the effective top tube on the old bike and it's around 22.25" so even the 17" bikes will generally have a longer top tube. There's no geometry lists online but here's a picture of the current bike when it was setup for around town duty.

Old Bike

Is there any other bike / brands I should look at outside of these? But it seems like the consensus is going with the smaller bike.

AZ.MTNS · 2 Weeks Ago

Look at as many as you can , ride them . You will know when you find the right one .

laherna · 2 Weeks Ago

I am 5-10 and have a 17" Rockhopper. Glad I picked the 17".

trailville · 2 Weeks Ago

Quote:

Originally Posted by makeitso

But it seems like the consensus is going with the smaller bike.

I don't agree. I'm not saying you absolutely should get a 19" frame, but I'm 5' 9.5" and know that a 17" frame would be way too small for me. I have a bunch of bikes ranging in size between 18" and 19.5".

Standover is overrated in bike fit. If I stand flat footed over my FS bike, there really isn't any clearance, yet it's never given me a problem. Take your current bike out on some trails and intentionally hit some real steep uphills and some technical features like big rock gardens, tight switchbacks or other things that are sure to make you put your feet down. Then notice what naturally happens when you're forced to put your feet down. You'll probably find that you actually end up leaning your bike and/or will be on your toes rather than flat footed. In either case, you end up with much more clearance. In addition, the suspension itself on modern bikes gives you some protection against coming down hard on the top tube. Plus, most bikes these days are aluminum and therefore have larger diameter top tubes that also provide a little protection. Wear some padded bike shorts and you have even more protection.

What you really need to worry about in a crash is hitting the stem. Ouch!

Top tube length (ETT) is far more important in bike fit. You may want to seek out some models that come in 18" . Most manufacturers sites will list their sizes and geometry.

xenon · 2 Weeks Ago

I'd recommend to choose the largest frame, that still allows you to easily sit on the rear wheel and get back up in the saddle. If you, like it sounds, are slim enough, it will, possibly, be 19" frame, rather than 17".
I am 175 cm. (5'9") myself. All but one my bikes have been L (20"), my only 18" frame felt too short to me. Yet I have my seat moved back to the limit and no problem moving my Southern end right onto the rear wheel.

sponger · 2 Weeks Ago

I'm 5 '10" with a 30" inseam and I feel comfortable on a 18.5". My last bike, which was a 17.5" felt a bit cramped.

perttime · 2 Weeks Ago

Those seat tube measurements are pretty irrelevant.
The length is what really matters when you are on the bike.

That said, I am about 176 cm (between 5'9" and 5'10") and my bikes tend towards the Medium/17" sizes. I like a fairly "compact" sizing that lets me move around the bike very well.

AzSpeedfreek · 2 Weeks Ago

Are you buying the bike to ride it or to stand over it?

I would steer you to the frame that fits you while you are riding it, not the frame that fits you while you are standing over it. If that means that it is an 18 or 19" frame then so be it. If it takes a stem of more than 110 or 120mm long for the bike to fit you then go up in frame size.

makeitso · 2 Weeks Ago

By the bikes I've rode it seems like I like a top tube around 580-600 so hopefully I can find something that falls within that range that has a viable standover height. Seems like I will be able to in the end esp if I look into used. But man, looking at the Specialized archive it seems like they changed geometries yearly!