Bike Frame Size - Between-Sizes

olawrence01

Hello All.,

Rather new to the forum, but have a dilemma perhaps shared by many.

Fixed to purchasing the SuperSix 2013 5 105 in liquigas team colours - http://www.cannondale.com/2013/bikes/ro ... kset-28007.

However, following assessing my fitting profile (attached) it seems I am between both the 52 and 52 frames.

Notes on each.

In the 54;

Top Tube length looks good
Measured size a little larger - but room to change the stem if needed.
Standover would mean a little too high, but I don't think this is too important?
Wheelbase is close to where it needs to be.
Reach is set at 38.3 and my suggested reach is 40.7 - again pretty close

In the 52;

Standover more comfortable
TopTube length it 53.5 vs recommended of 54.9
Bottom Bracket drop a little more in line
Wheelbase too short(ish)
Shorter head tube length, but I don't think this really matters.
Minimal affect between reaches with this geometry
Front centre distance not too good vs my fit

Me:

5' 10' height
30,5 in inner seam

I have tried both frame sizes, by sitting on a turbo trainer and both seem good.

However wondering from experience, would be smaller frame give me more scope to change and fit if needed?

i've a rather long torso and therefore need a long top-tube and shorter seat tube height.

Any opinions would be great

Thanks again

sloppyschleckonds

olawrence01 wrote:

However, following assessing my fitting profile (attached) it seems I am between both the 52 and 52 frames.

I don't see any problem here.

Grill

If between sizes, go smaller. Recommended top tube height isn't really an issue as you can compensate with a longer stem. You also need to take into account that different seat tube and head tube angles change the effective top tube length (I have one bike with a 535mm TT that has a longer reach than my other with a 550mm TT both using 110mm stems).

Pooter

i can't see why you're even considering the 52cm. You'd have to use a massive 13cm stem.

Grill

130mm for a stem is fine. Anyway, you should be looking at stack and reach, not focusing on top tube length or other arbitrary metrics like wheelbase (omg 2mm!) or standover height.

olawrence01

@Pooter - Thanks for the advice. I see where you're coming from, my recommended Stem is 115mm based on my fit and the 54cm would provide for a 100mm; a simple and cheap upgrade to make it a 115mm if I feel a little uncomfortable.

@Grill - It seems people are 50/50 about how to approach being between sizes. Some say focus solely on effective TT length. Others say different.

What would be the two single most useful measurements?

And does anyone on this forum look into standover height as criteria? I don't see standover as too important considering I hope to not put my foot down too much.

I seem to be thinking 54cm is the most appropriate as top tube length seems ideal.

@SloppySchlekonds - My problem is that the geometry on both frame sizes seem to mix with my fit.

I'm looking into the 54cm option, my always know that it's hard to make things smaller, and easier to make them bigger on a bike.

Help appreciated and I'll let you know how I get on.

Ollie

olawrence01

@Grill - I see that a 130mm stem would work on the smaller size, but would have thought that picking a top tube length most appropriate to my torso (ie reach) would mean that I select a more appropriate bike.

I can then work out the best stem length to suit, which according to the last fit would be a 115mm and a 549mm effective top tube.

It's the seat post height that throws me, and seems to be dividing opinion here.

Being short, with a longer body makes things hard in terms of bike sizing.

matt-h

I was in the same position 2 years ago and went for the larger frame.
I wish I had gone smaller

Matt

Bozman

There seems to be a major cock up by the frame manufacturers here, the average height of the UK male is 5'10" and this seems to be the height where folk have the "stuck between sizes" issue. Me included.

olawrence01

@Matt-H - what was your particular problem?

@Bozman - did you end up chosing the smaller or larger size?

I'm leaning more towards the 52cm now due to seat tube heights, the tube top could be extended by using a new stem, and I wouldn't want to have issues with lowering my seat and not being able to drop the headset low enough.

@Grill - you think that sounds wise?

Grill

I've had bikes that were slightly too big. Not nice.

The two most useful metrics for frame sizing are stack and reach. Saying 115mm is your ideal stem length is a bit silly as your stem length is dictated by stack and reach, so it will change depending on given geometries. Also 115mm isn't the easiest to come by which leaves you a bit screwed for choice.

Again, standover height isn't important. Keep in mind that cleats will make you a bit taller and you'll always have one foot clipped in allowing a lean.

Seatpost height is arbitrary. More is pro and less is retro, what's important is that you're not at the insert limit.

You're concentrating too much on the details. The reality is that a few millimeters here and there is not going to make much of a difference. You said you felt good on both bikes. To me this says that you're not too cramped on the 52 which is currently set in a fairly small configuration. Have them whack on a longer stem (probably comes with 100mm which I've always found twitchy) and try it that way if you want to be certain.

Below is a picture of one of my bikes for reference. The top tube is 535mm and it has a 110mm stem, and the geometry is almost identical to the 'dale in a 52 (the headtube being the biggest difference). Keep in mind that I'm 5'11" with a 32" inseam and all my bikes are 'M'.

matt-h

olawrence01 wrote:

@Matt-H - what was your particular problem?

Hi, I have a short inseam and long in the body.
The 54 was only just suitable for stand over but I have little seat post showing and need a shorter stem.
I could have had more clearance and a longer seat post which should give more comfort - and look nicer

Tempted with a handbuilt steely for the next bike 8)

Matt

matt-h

That bike is exceptional Grill!

Matt

olawrence01

Thanks @Gill - you've been a great help.

Also looking through @Matt-H's experience I think it best to try the 52' with a longer stem.

My fitting should have also touched upon my stack and reach (hence why they provided me also with a recommended stem of 115) but I can't figure it out from the charts.

Are there any experts in looking through fitting charts?




Seems my reach is around 40.7, but not sure of my stack as it doesn't seem to calculate it?

Thanks for your help all.

Appreciated,

Grill

I can't tell the frame stack as it's not a real bike but the reach is 407mm. The handlebar S/R is 580mm and 491mm which is more important. The head tube angle, head tube height, and spacers used will all impact the size of stem you'll ultimately need.

While the precision of the diagram is nice, you can see that you shouldn't sweat the details. For example 43cm c2c on the bars isn't a size that's produced so you'd probably be better off with 42cm c2c.

olawrence01

@Gill - thanks for this, understand the rookie question in asking of stack when I don't know the specifics of the frame.

I would say from the geometries of the Cannondale SS that the 52cm is looking more appealing.

I;ll then be able to adjust things to see that the stack/reach with regards to handlebars are appropriate.

Also understand the point around following details to the letter. If i followed this diagram to the letter I would need a customer build (although that would be nice)

Looking at your WyndyMilla, I'm tempted to pay a visit. They're pretty close by me...!

Great looking bike.

Keep the input coming, perhaps those riding Cannondale also?

I'll let you know how I get on, and perhaps a picture.

lc1981

I was torn between a 56 and a 58 cm when buying a SuperSix earlier this year. I'm 6'1.5" (187 cm) with relatively long legs for my height. I went for the 56 in the end and then had a bike fit with Adrian Timmis. He stuck a 130 mm stem on it. He may well have been able to make the 58 fit just as well - I'll never know - but I'm very happy with the smaller frame.

letap73

Generally bike fitting advice on the internet doesn't work. I am barely 5.10 - a 54 SuperSix is on the small side for me - but will fit, a 56 would fit better (no chance with a 52!). If you can get back on the turbo trainer with the bikes you tried as before and with the help of someone who has good experience of bike fit - they can offer better advice.

The competitive cyclist fit calculator is useful:

http://www.competitivecyclist.com/Store ... orBike.jsp

kajjal

One thing to consider is what type of riding position you prefer. Calculated bike fits are a guide to help you. I am over 6ft6 and going by most bike fits my saddle to bar drop should be about 3 inches but I prefer being more upright so only have about an inch drop. Also going by bike size charts I should have the next size up but my current 62cm road bike fits me well and I like the feel of the ride.

Fitting a bike that is a bit too small is easy enough fitting a bike that is a bit too big is very hard work.

olawrence01

Hi All

Thanks for the helpful info.

Going by the majority of bike sizing and my fit sessions I'm looking at the 'Dale in a 54 only because;

It has a C-T (measured size) of 52cm
Top-Tube length of 54.5 leading to a reach (plus stem) of 64.5
Reach of 38.2 cm

I think a size 52 (measured size 50cm) would give me a good position but wouldn't allow me to get the reach without a huge stem.

Please I think I'd fit the 54cm without having to put in too much effort.

I will try both out again and see.

Thanks all
Ollie

mfin

Ignore any generalisation people make by saying what frame size they ride even if they state their height and inside leg. It is not enough to make any exact assessment but it does give them enough information to put forward an opinion which might or might not be applicable. Firstly, you don't know if they are in the right position, secondly the 'right' position is not an exact fact... thirdly, height and inside leg ignore where the proportions are within the limbs, make no allowance for flexibility, age, pre-disposition of the kind of position they want to ride in.

If you are not sure, or can't think it through correctly, exact sizing decisions just can't be made via going with opinions of people on the internet. Decide what you need and make sure you understand everything you need to (ok, maybe by asking questions for sure to help along the way).

One thing above... 130mm is NOT a ridiculous length stem for 5ft 10, it's just at the upper range. Some people think through amateur armchair guessing that it slows down steering, but invariably it will be paired with a shorter wheelbase so this counteracts it perfectly. You don't see tour riders with 130mm and 140mm stems complaining about slow bike handling do you? No. Less than 110mm for a 5ft 10 rider generally means a wrong size frame or a person who rides 'mary poppins' style, and these people, unless they are injured or over 60 are riding in weird positions (remember that some people who answer will be completely different flexibilities and that some are riding in the wrong position... maybe ask the people who did your bike fit for advice, not people on the net who want to re-inforce what is 'right for them').

blackpoolkev

A few years ago I was faced with a similar problem.I opted for the smaller version -it was okay but not quite right.
Last year I changed my frame,I chose one that wasn't between sizes - it is perfect.
Don't restrict yourself to one particular bike, other brands may fit you better.

mfin

blackpoolkev wrote:

A few years ago I was faced with a similar problem.I opted for the smaller version -it was okay but not quite right.
Last year I changed my frame,I chose one that wasn't between sizes - it is perfect.

This is worth noting, some models just don't themselves to being correct in any size some people. Most people have heard of the concept and can comprehend it as it is so easily said, but it's worth people understanding it enough to avoid it happening if they can (and if it means choosing a different bike than the one your heart was set on, so be it).

DeVlaeminck

Ok i know height doesn't determine frame size but a 52 cannondale is tiny for 5'10. If it's comfortable then great but is the fit similar to what you've ridden before?

ilovegrace

This is my take on the subject.
Please note, I am as green as grass with regarding to this subject so are probably a good model for the exersise !
I am 5ft 10 1/2 no idea of inseam etc .
Recently I bought a secopnd hand Lappiere Xelius 55 frame 570 top tube.
This bike stretches me right out and was bought in the hope of alliviating pain in my back sufered with previous bikes. ( this is a long standing dic problem)
On trying the bike . 10 - 15min test rides it felt good and the purchase (eventualy ) was made.
Now 5 months down the line my back is still bothering me and I have had to redice the stem from 120 - 90mm.
As I see it , there is nothing , and I include bike fit , that can replicate the feeling of riding a bike as good hard riding of ther bike.10-15 mins is not enough.
I was in Pickering last week and visited the LBS , they had a full range of Treks , there was an advert for the use of test bikes for weekends at a cost of £25.
This is the key to me , in future this is what I would do , try 2/3 bikes ,cheaper than a bike fit , hammer them over a couple of 50 mile rides up hill and down dale in the North Yorkshire Moors.
If you dont know if a bike fits and is comfortable after that you never will.

What do you think of this theory ??
regards
ILG

olawrence01

Hello All

Thanks for the contributions, and opinions with regards to frame sizing. It seemed from the geometry that I could get either bike to fit, but didn't want to feel like I'd chosen a frame size that I would regret.

After visiting the LBS today I was able to get back on a 54' cannondale SuperSix with exact geometry as the model I'm after.

After adjusting the total saddle height, noting the reach to the bars, as well as how 'strecthed' it felt on the top-tube I decided it was perfect.

Whilst the frame is slightly larger, and therefore the saddle will not have such a tube height showing, the front headset has so many spacers and even a huge spacer lower down should this be an issue.

I can also adjust the stem length if needed, and means that I wouldn't need a 130mm stem. In fact, the stock 100mm would suit just right.

From an earlier post, a good bike fit would mean that I could make both bikes comfortable one way or another. I therefore chose the bike with the better reach to avoid my position being overly 'aggressive'.

The only thing I will miss on the 54cm will be the 'pro' look of riding a smaller frame size.

Keep the advice coming, I am to purchase this week and can't wait to set it all up

Regards
Ollie

lc1981

DeVlaeminck wrote:

Ok i know height doesn't determine frame size but a 52 cannondale is tiny for 5'10. If it's comfortable then great but is the fit similar to what you've ridden before?

I think this is a good point. Although I went for the smaller of the two sizes I was looking at, my height placed me closer to the borderline between the sizes according to the sizing charts, whereas at 5'10" you were probably towards the upper end even of the 54.

olawrence01

@Ic1981 - Yes, I always fit every par of the 54cm apart from concerns around the saddle and drop to the bars.

As it happens, a 'Dale 54 frame has a measured size of 52cm (C-T) unless I interpret wrong. The 54 includes seat post section of 2cm. Therefore a C-C size of around 50.5cm.

My recommended C-C is at 50.1cm given my proportions and a large reach of 40.5cm I would always need a slightly larger frame.

It is my reckoning that reach is even more important than stack, where I find it hard to find any bike that works with my shape.

As previous have mentioned, wheelbase and other things seem to be arbitrary.

The important thing is that I've got enough on the 54cm to ensure bar is dropped enough below the saddle and even some flexibility if I want to relax the position slightly for different ride types.

Anyone have any thoughts to the contrary?

@Grill et al - thanks for all your input. I'll send through some pics when I get a chance.

Now I just need somewhere to put the thing during the winter.

blackpoolkev

Just to confuse/help, why choose a Cannondale Super-Six (which has a race orientated geometry) with lots of stem spacers? The Cannondale Synapse has a slightly more comfortable set up, including a longer head tube. They are similar in price for equivalent spec, your Cannondale dealer should be able to let you try one.

scottishgeek

Being between frame sizes myself always makes buying a new bike interesting. I bought a Cannondale CAAD8 from my LBS at the start of this year and went through the same dilemma eventually going for the larger of the two sizes and have no regrets.

Later in the year when it was time to replace my relatively ancient commuter I looked at the Cannondale CAADX and was still between sizes. My LBS was very helpful and explained there opinions (which of course differed between staff members and became a very interesting debate). Eventually I opted for the smaller size this time as I knew my commuting riding style differs slightly from my weekend road use.

At the end of the day I am very happy with both bikes as they suit my personal requirements.

littledove44

If the distance from finger tip to finger tip with your hands stretched out is more than your height then get the bigger one. If not, get the smaller one.