Clamms

Hey I'll be picking up a new sirrus sport disc next month. I've taken it out for a ride at the LBS and I'm pretty much right in between the medium and the large. I'm 5'10 and 49 years old for what it's worth. My inseam is 32" (at least that's what length my jeans are, is that how you tell your inseam?). Is it better to size up or down?? Thanks...

ColdCase

You may find another brand may fit just right. I was shopping for Trek as they are suppose to fit short arms better than most but I found the Specialized frame fit better. Personally I think its easier to adapt to a frame a little too large than one a little too small.

FrozenBiker 

Did one feel more comfortable than the other? It may be best to take another ride on both for confirmation.
The standover height is 30.94 inch on the medium, compared to 32.32 inch on the large.
The top tube is .78 inch longer on the large, so just a slight stretch over the medium.

ypsetihw

put on your bike shorts, put a book up in your crotch against a wall, mark it with a pencil, and measure to the floor. it'll probably be longer than 32"

Clamms

I had the same issue with Trek when I test drove that one.

ypsetihw

I was gonna say the opposite, usually you have more room to push the saddle back than you do to push it forward, and I'd personally rather have a slightly longer stem than one that was uber short, just for the overall feel of the handling of the bike. Then again, your overall cockpit setup makes a big difference. If you generally have a large saddle to stem drop then the smaller frame will feel bigger with the large drop. If you like them even, then the reach may feel cramped on the smaller frame.

corrado33

I agree with this. It's MUCH easier to make a small bike slightly larger. It's extremely difficult to make a large bike smaller. (Especially if it already comes with a short stem.) Buying a bike that's too large for you comes with a host of problems. It could have cranks that are too long for you. It could have a top tube that's too long for you, it could have handlebars that are too wide for you. None of these things are a problem if you buy a smaller bike. If cranks are too short you won't hurt your knees (unlike if they're too long.) If the handlebars are too wide you'll feel it and be uncomfortable, but if they're slightly too small you'll be fine.

practical

My preference (purely personal, not scientific) is to get the largest bike that I can stand over without hurting myself. Maybe because my arms and trunk are a little longer than normal so that longer bike feels better. You can adjust the handlebars a bit and the seat back and forth a bit. I'm only 5-10 and have a 56 cm bike and 58 cm bike. I bet most people would say the 58 cm bike is too big for me, but I really prefer it even though the 56 is a much better bike.

dim

Get the smaller bike, and get a longer stem, and adjust the saddle accordingly

SirrusEliteDisc

Clamms, I'm 5'10" with a 32" inseam. In October of last year a Medium 2014 Specialized Sirrus Elite Disc caught my eye at the LBS so I took it for a spin. I had previously been riding large frame bikes but the Medium felt so much better to me that I bought it and sold my large frame bike. I am 57 and have a lower cervical fusion and not being quite so stretched out just feels better to me. Buy the size that fits and feels better to you.

dim

I've been buying older bikes for cheap, riding them for a few weeks then selling them for profit and buying better

I was going to buy a Bianchi, and sent Bianchi my measurements.... they advised to buy a 53-54cm frame

my latest road bike is a 50cm. I changed the stem and adjusted the saddle forward/back position

normally it takes a few days to get used to the geometry of a bike .... this size suited me from the beginning and on this one of 50cm, I am flying.... really comfortable, handles corners extremely well

I've just bought a Surly Long Haul trucker, and have bought a 50cm frame

what I have found, is that on a larger frame, it's fine on straights but when it comes to cornering and handling etc a size or two smaller than what is normally used makes a huge difference

Jarrettsin

Was having the same problem and went with some info I found here on BF and it worked for me (I went smaller)

"Measure your wingspan if it's greater then your height go with the larger. If the same or smaller go with the smaller frame"

yashinon

You got me thinking about this. I ride a 17.5 Trek Fx, which seems to fine but then again. Trek shows the 15 goes to the person's height of 167cm and the 17.5 overlaps starting at the height of 164cm. This is a pretty wide span.

ColdCase

True, but the OP is talking about bikes with identical components, just some frame dimension differences. If I go too small I feel cramped and the handling is twitchy. Go too large you may have some pressure on your wrist and would have to perhaps change the handlebar or stem to bring it closer. Many here prefer the longer bike's more stable and open ride, however. But for the two bikes he is talking about, there is not that much difference and either one can be easly adapted... just that its hard to make a small bike not feel cramped. One can make a large frame feel smaller more easily. For performance riding it may make a world of difference, but for casual riding, eh.

canklecat

When I was shopping for a decent used bike to get started again last year I snagged a Globe Carmel with medium compact frame. Technically it's intended for riders up to 5'10" but it suits me well enough just by raising the seat post a bit. Odd frame, with longer than average wheelbase (48", I think), so it feels larger than a "medium".

FWIW, I'm 5'11" with 33" inseam, and longish torso and arms relative to height and leg length. Hard to find off the rack jeans that fit perfectly, since most stores carry 32 or 34.

No problem with the bike though. No knee pain, beyond the occasional twinge. I scooted the saddle all the way forward rather than back, because it's already a slack geometry frame. Forward puts the saddle in a more natural position and feels better ergonomically, especially climbing hills while seated. Only other adjustment I've made is to gradually lower the handlebar stem height and pivot the handlebar forward slightly to suit my longish torso and arms.

If I bought a road bike with horizontal top tube I'd be fussier about fit. But compact frames seem pretty forgiving to folks at that awkward in between size.

Clamms

Thanks for all the replies. Doesn't seem like there's a real consensus on whether to size up or down. I'll probably take them both out for rides again and just go with the one that feels more right.

corrado33

I'm sorry, but we'll have to agree to disagree. You can ALWAYS put a longer stem or a longer seatpost on a smaller bike. You can't always put a shorter stem or lower the saddle on a bike that's too big. If you're buying a larger bike than you would normally ride because you want a different type of fit, then you're buying the wrong type of bike. That's my opinion of course.

You have to be careful about frame sizes. Often times it'll look like they have identical components, but the larger size could very well have longer cranks and wider handlebars. It's not something they advertise very well. Many bikes switch between 172.5 and 175 mm cranks around 56 - 58cm sizes, which, depending on the build the OP has, could certainly be what he is riding. Would he notice? Probably not, could it cause knee issues if he ends up riding a lot? Perhaps. Stuff to keep in mind. I'd imagine that's where they also start putting wider bars on bikes as well, but I can't be sure of that. Bars that are too wide will DEFINITELY be noticed, trust me (first hand experience.)

Jarrettsin

good idea

ColdCase

You are talking generalities and theory. The OP has two specific bikes, one a little large, one a little small. The only difference between them, in fact, is some frame and wheelbase dimensions, perhaps a little rake/trail. Everything else you mention may be OK in general and for widely different frames, but entirely irrelevant here.

You can extend the seat post and stem to cram a large body into a small frame but, for casual riders, it may be skittish to handle and tiresome to ride. It is easier to set the seat post properly on a slightly large frame and either use a swing back handle bar or set back stem. Provides a more stable and relaxed ride because of the longer wheelbase. Small frames usually loose the second water bottle holder and a few other areas are compressed, if that is at all important.

Bottom line, as mentioned, is the Op should try both and pick the one that feels better. No big deal either way for an in between size for most casual riders.

jimmie65

It's going to depend on not only the bike's geometry but your geometry and riding style.
I'm 6' with short legs and, therefore, a long torso. I also prefer a more upright riding style. I've tried jacking up medium frames with extended seatposts and handlebar risers; it made for an OK ride but not great. Large frames work much better for me.

DorkDisk

A vote for smaller on compact frames, as it maximizes the advantages of this type: lower standover, stiffer + lighter frame, and a longer more compliant seatpost

The point is "between" sizes, as in they both fit, not how a wrong sized bike doesn't fit

Looking at cyclists and their setups, one would notice that the highest mileage riders have been sizing down since sloping top tubes appeared. This favors the lower bars/flat back/more front weight position used by high mileage riders.

Frame design has much to do with it. Many hybrids now are a combination "slope up" and "compact" types. A slope up frame rises up to create a higher headtube. It resembles a compact frame due to the non horizontal top tube but the intent is different - to raise the handlebars. Many beginners set up their compact frames as slope up frames. A well sized compact frame should show at least 7 inches of seatpost

5-10 here also. twenty six years of 17" compact. Everyone tries to put me on 19/20" but they're too long for my short torso

fietsbob

I was 5'10" when I rode horizontal top tube Road bikes , they still fit.. (old people due to gravity get shorter)

I favor a long distance fit, more sit up, less aero - in the drops race posture.

fietsbob

Quote:

My inseam is 32" (at least that's what length my jeans are, is that how you tell your inseam?).

that leaves off your Feet .. pull something up between your legs (Still have some LP records? ) and have someone mark the wall .

that is your max stand-over 'inside leg' measure ..

quicktrigger

Same size, same inseam. I was/am more comfortable on a large. Seems my legs are a bit long. BUT, I also need a shorter stem with a steeper angle. Ended up with my Sirrus being large with a 80mm stem (compensates for the dimension differences between large and medium) with a 17 degree angle. Has worked well for me. Is it by the book? Probable not... don't care. What works is what works.

QT