Frame size advice

apprent1ce

I currently rider a supersix size 56 which I feel is on the large size for me - I have a shortish inseam (81cm) vs long torso (height 178cm) I have had two bike fits over the last two years, the first said bike too large and swapped 100mm stem for 90mm then a second (cannondale dealer) said the bike okay but swapped 90mm stem for a 120mm. I have ridden around 5000km on the bike and I think a 100/110mm stem would be a better fit for me. The seat height is also barely above the bar height.

I am now looking at the Canyon Aeroad as a new bike and would be grateful for advice on fit. The Canyon calculator recommends a small. At the recent NEC bike show I test road both the small and medium and the small felt a bit cramped whilst the medium cockpit felt right.

The stem on the small is a 90mm and I wondered if I changed this for a 110mm would this give me a position on the small closer to the medium whilst offering a more standard seat position?

I have been going through the geometry charts but struggle a bit as I’m not sure how key the various considerations are; in isolation, many measurements appear to be within a few mm. The position is more aggressive given the shorter stack, but that was fine.

Any advice greatly received.

Cheers

drlodge

I find the easiest way to match frames is to look at the effective top tube length, bearing in mind seat angle. On the Supersize the STAs are all the same, so you have 560 eTT for the 56 and 549 eTT for the Small.

You're about an inch bigger than me, and I find a "54" frame with an eTT length of 545mm, STA of 73.5 degrees is spot on. One inch change of STA means a 10mm change in eTT length (steeper STA means shorter top tube).

However it seems like the top tube length of your supersix is about right, although the seat tube length might be a bit long.

What is the Canyon geometry like, is there a size with a top tube of around 555mm?

mfin

Drlodge has written a couple of things there which might confuse you as far as the wording goes.

If an STA is steeper (more degrees) on one bike than another, and both have the same length ETT then the one with the steeper STA will have the effect of being longer. That top tube is the same length but it is now shoved further forward on the bike.

Your problem is not helped by not knowing your Stem length is correct on the Supersix, if you can decide what is best first of all for sure, then it will help a lot.

Also, knowing your Saddle Height from centre of BB to Saddle top would help, or is that the 700mm you have put in your table? (and you've put some kind of range for the other bikes?).

As per DrLodge, I think the current bike is likely wrong and a bit too big. You've sort of got a bike setup which is quite long there, which could be fine if you are very flexible and 'pro', but that doesn't make sense as you are saying you have so little saddle to bar drop.

My guess is on an an Aeroad you would want Small not Large, BUT, it has got me wondering if you are picking a bike here with geometries not suited to you. That said, from what you are saying about the test rides, I think if the drop wasn't a problem on the small, your logic of getting a Small with a longer stem that it comes with does sound quite logical on face value. So, if I was to put my money on anything here, I'd say the Small with the right length stem is the most likely best chance of a fit on the Aeroad.

I suppose these Canyons come with an integrated cockpit so it's not so easy to change things around stem-wise to get it right, hence why it would be a lot easier if you were sure of your stem length on your existing bike.

Also, if they are integrated you're going to have to take into account the reach of the Canyon bars compared to what you are running, if that reach value is significantly different this might affect choices of stem length too for a good reach to the hoods etc etc

sloppyschleckonds

Med

apprent1ce

Many thanks for your responses.

With regard to stem length, my thinking is that the M Aeroad felt perfect and this has top tube of 560mm + stem of 100mm giving 660mm to bars. This compares with my supersix 560 + 120 = 680mm and S Aeroad as supplied 549 + 90 = 639mm. My thinking was if I change the Aeroad Small stem to a 110mm this gives 659mm which matches the large’s dimension.

The saddle height from BB is 700mm on my supersix (measured through seat tube) and the ranges given for the Aeroads are the min/max limits. On the Medium bike 700mm is below the minimum 710mm stated. On the supersix my saddle to bar drop is < 15mm. The seat tube length on the small is 508mm compared to 540mm on the supersix and the seat height is comfortable in the range (690-797mm) albeit still at the lower end.

Is my thinking right or is this a over-simplistic analysis? I am okay with the maths but not the nuances of the fit!

One other thing is that the handlebar width is 390mm on S, 410mm on M which compares to 420mm on my supersix. How important is this? The entry Aeroad doesn’t have the integrated cockpit so I assume swapping stem/bars should be possible.

Thanks again.

bristolpete

This is excellent. I am effectively the same 'body geometry' as you and it is difficult, though not impossible to make a bike work. I have had a few bikes over the years for this issue as people like us are large in reach and torso, but medium or small in the leg. I currently own a synapse which I settled on as an interim bike and chose a 54cm which is very steep in the seat tube and slack in the head tube. It is a nice ride and great on the whole, but a bit fudgey on the climbs. I suspect your best bet would be too look at a good compact frame such as a tarmac, tcr etc as they seem to match the short legs longer body rider better. I don't buy into the you can make a small bike bigger to a point, but the bigger upper body sometimes means that the correct frame on paper is akin to descending on a BMX ! Think about an inline seat post where poss too, but ensure you do not compromise the rear of the bike to get to the front. Though crude to many, apply KOPS as your reference on pedal stroke...

I too tired a 56cm evo and lush as it was the stand over rendered the bike a bit big, whilst the 54cm was simply too small and the drop, which of course is based on 'pro rata' head tube sizing was too much....

mfin

apprent1ce wrote:

Many thanks for your responses.

With regard to stem length, my thinking is that the M Aeroad felt perfect and this has top tube of 560mm + stem of 100mm giving 660mm to bars. This compares with my supersix 560 + 120 = 680mm and S Aeroad as supplied 549 + 90 = 639mm. My thinking was if I change the Aeroad Small stem to a 110mm this gives 659mm which matches the large’s dimension.

The saddle height from BB is 700mm on my supersix (measured through seat tube) and the ranges given for the Aeroads are the min/max limits. On the Medium bike 700mm is below the minimum 710mm stated. On the supersix my saddle to bar drop is < 15mm. The seat tube length on the small is 508mm compared to 540mm on the supersix and the seat height is comfortable in the range (690-797mm) albeit still at the lower end.

Is my thinking right or is this a over-simplistic analysis? I am okay with the maths but not the nuances of the fit!

One other thing is that the handlebar width is 390mm on S, 410mm on M which compares to 420mm on my supersix. How important is this? The entry Aeroad doesn’t have the integrated cockpit so I assume swapping stem/bars should be possible.

Thanks again.

Your logic is about right.

You could go either way. You are an odd one as you have naff all drop (15mm you say), if you fancy a bit more drop you'd want to go with the Small and the saddle height will be more in the range intended for that small frame.

Yes bar width is important, seeing as you like your 420 and seemed to like the 410, if you can spec a bar in one of those sizes do that.

I'm not saying you are odd dimensions and fit, but you can see not a lot of people are chiming in... this is because normally the Geom of an Aeroad suits a racier/flexy person, but the Geom you are heading towards for different reasons even though they seem to make sense for you.

That said, there is an alarm bell here, you say you are 178cm tall and your saddle height from top of saddle to BB is 700mm? Are you sure, measured in line with the seatpost? (Just double checking as your proportions are definitely short in the leg! ...hence why an Aeroad seems low at the front for many but is not at all for you).

apprent1ce

Thanks for replies, they're very much appreciated. It's all a bit bizarre really as until now I've never had any sense that I have particularly short legs - jeans always been 30W 32L Regular!

This is a pic of my supersix, I checked seat height from BB and it is 708mm (so just at the minimum of the Medium Aeroad). I could slam the stem to create a bit more drop to the bars, but over last six months, given comments from bike shops, I've been convinced bike is too big (newbie mistake) and have been saving for new bike. Also, there's not enough seat post for my park tool to clamp onto.

I've done 100+ mile rides on this; occasionally there's some discomfort in lower back on long rides but nothing a few stretches doesn't deal with.

trek_dan

I'd be amazed if that seat wasn't way way way too low. I mean just look at it and you can tell its not setup right surely? Your proportions are similar to me (I'm 5'10" with a 31" inseam) and I run my seat at 760mm from BB to top. Get a bike fit done on the Supersix before you purchase anything, your knees will thank you for it

sloppyschleckonds

Bikes in kitchen thread please.

I like bikes with the handlebars higher than the saddle

viewtopic.php?f=40044&t=13039762

svetty

trek_dan wrote:

I'd be amazed if that seat wasn't way way way too low. I mean just look at it and you can tell its not setup right surely? Your proportions are similar to me (I'm 5'10" with a 31" inseam) and I run my seat at 760mm from BB to top. Get a bike fit done on the Supersix before you purchase anything, your knees will thank you for it

Would tend to agree - at 31 inch inseam I'd also expect your BB to saddle top measurement to be approx 75 - 76cm: 708mm does sound low to me. I assume you have 172.5cm cranks as they were OEM on that size frame IIRC.

Also you are currently riding with a few spacers below the stem. If you bought a smaller frame size you'd need a really tall spacer stack to get the same bar height (unless you get a steeply angled stem).

mfin

Now you've confirmed the saddle height, I'd be amazed if the guys above are wrong, it sounds like you are running your saddle way too low, could be about 40mm out or something like that.

You need to get this checked out in my opinion, if it is out, you could be in for a pleasant surprise on how much quicker you will be.

You need to sort this fit out before you do anything, it will likely completely affect what bike geometries will work for you. You might find you don't like the drop you'll get if you are inflexible, which will start to rule out bikes like the Supersix or the Aeroad. Partcularly this will be even more true if you size down as also mentioned above.

apprent1ce

Thanks for the replies, they’re much appreciated.

The frustrating bit is that I’ve had two bike fits, the first was a basic £40 job but it was a high end lbs. The second was with a cannondale dealer, full £100 job with cannondale computer fit analysis… The slight reluctance for me is that if previous fit is so wrong who should I go to, as spending another £100-150 is another knock to the new bike fund, although I do appreciate it is money well spent if it prevents a costlier mistake. Can anyone recommend someone within say 50 miles of Cambridge?

I know it looks wrong, but on the seat height measurement, my cranks are 172.5mm so maximum leg extent is 708+172 = 880mm = 34.6” My understanding is that you should have a straight leg with heel on the pedal, so is this really that far out?

Thanks again.

trek_dan

Is your flexibility severely compromised somehow? I wouldn't have thought any bike fitter would setup a road bike with the bars higher than the saddle unless they absolutely had to. Did either bike fitter do any checks to this effect before your fit?

apprent1ce

Trek_dan, Apart from observing I can't quite touch my toes, nothing. I ride on the drops and I weigh 68kg with a small bit of middle age mid-rift excess.

bristolpete

Have reread this thread a few times and I remain convinced that a compact frame will suit you more than the Supersix, which even if you do have good reach leave little seatpost showing and thus, just looks too big. Think about

Tarmac.
TCR.
S2 / S3

Bike will sloping top tube and decent stand over.

trek_dan

apprent1ce wrote:

Trek_dan, Apart from observing I can't quite touch my toes, nothing. I ride on the drops and I weigh 68kg with a small bit of middle age mid-rift excess.

I'm not the most flexible at all, I particularly struggle with my hips and hammies but I'm basically the same height and inside leg and look at how much different our bikes are setup. I still think theres something not quite right about the Super6 setup.

meesterbond

Just to add another data point in the mix, I'm also 5'10 with a 31" inseam (or thereabouts) and my saddle height is 741mm (actually 2-3mm higher now). 708mm does sound low.

I used to ride a Cannondale - a six13 in a 55cm - never really got on with the geometry. The horizontal top tube always meant there was very little seatpost showing.

dwanes

To be honest despite what others have said, if you were to slam the stem on your supersix the set-up would look ok. They are not supposed to have loads of seatpost showing as the geometry is very 'traditional'.

Why do you have all those spacers under your stem? If your back cant take it its not your bikes fault? If you feel to stretched out why on earth do you have such a long stem?

You dont need another bike fitter to tell you what to do! You need to use your head and sort it out yourself!

It sounds like you could be making a very expensive mistake buying a Canyon.