In between sizes... what to do?

Alfie_T

Hello

I am in the market for my first so-called "proper" road bike. However geometry wise I seem to be in between two particular frame sizes. I currently own and ride a cheap and cheerful roadbike which has a 56.5cm top tube, 52cm seat tube (center to top).
If my budget can stretch a I am interested in a Wilier Triestina Mortirolo but I would appear to fall in between two frame sizes. The medium Mortirolo has a 53.8cm top tube, 53cm seat tube (center to top) while the small has a 52.5 top tube and 50cm seat tube (center to top).

I am 5,6"/5,7" with a 31" inseam.

Should I just discard the Mortirolo as size-wise I appear to be in no mans land?

While I have not posted prior to this I have followed the forum for a little while and I have noticed lots of people ordering Focus and Planet X bikes, spending £1000 or more on a bike, I presume using little more than a sizing table?

alfablue

I think the only way is to try the bikes out.

Probably top tube length is more important to you than seat tube length as this will determine the reach you have to the bars, whilst seat tube lengths of different sizes are more easily accommodated by shifting the seat height. You can of course adjust reach by swapping stems, but there is less adjustability, and changing stems is less easy and of course costs. Bear in mind the top tube length may be two different dimensions, the actual top tube length, and the "virtual" top tube length, i.e. the length of a horizontal line between top of head tube and seat tube or seat post. The amount of difference between the two will depend on the amount of slope on the top tube, and the angle of the seat tube. Sorry if this is obvious but make sure you are comparing the virtual top tube measurements on your existing and prospective bikes rather than actual (often manufacturers quote both actual and virtual lengths).

From your height/leg measurements it sounds like you have a shorter torso and longer legs (the opposite to me!), so again the smaller frame may be better, but really the only way is to sit on them or preferably test ride them. The overall comfort may well depend on other aspects of geometry also.

It could well be that you could get comfy on either medium or small with the necessary adjustments, if it were me I would be thinking small though. If you can't try them out (say, because you must buy online to get within your budget), then see what the returns policy is for the vendor, should it not be right for you (actually you do have the right to return for a refund within 7 days under distance selling regs, but there will be small print, such as bike is unused, sold as stock rather than custom parts fitted etc. Note, restocking fees are not allowed, but some sellers try it on!).

There are various online calculators like this one, could be useful as a rough guide. (This one seems better than some as it accounts for torso, leg and arm length).

redddraggon

The simple answer.....get the smaller one.

On buying online....as long as the bike you buy isn't too big or massively too small, it can be made to fit you, with a change of stem length.

I'm 5'8" and I'd go for the small bike.

alfablue

Reddraggon put it a bit more succinctly than I did! :oops:

Alfie_T

Thank you for the replies.

Not entirely certain about the seat tube measure being actual or virtual. This is the sizing chart I was using: Mortirolo.

I guess I could get away with either frame though. If it is the actual seat tube measurement on the Wilier chart thenthe medium's 50cm seat tube that is just a cm or so higher than the actual seat tube height on my current frame (who's virtual seat tube height is 56cm).

While there is a good few cm of clearance between my current top tube and my crown jewels the jump up to 53cm is perhaps a bit too much. It maybe touch and go so to speak.

alfablue

Hi Alfie

It is the top tube that is "virtual" or "effective" - in the link you posted it is the dimension marked L which is the effective top tube length.

Really it is top tube length and crown jewels clearance that is probably more important than seat tube length, its just frame sizes are expressed in terms of seat tube length, but you really should focus on reach to the bars first, I reckon.

Note that crown jewel clearance doesn't need to be so much on a road bike as an mtb. 25mm will do, tthough I would get the smaller "standover height" if it had the right reach. These days top tubes tend to slope anyway, giving much more standover than that (on compact / semi compact frames) so clearance is unlikely to be an issue. Don't work on the basis of getting the maximum standover (seat tube lenght + bottom bracket height) that you can manage, that is like buying a child the largest possible bike so that they have growing room - I guess you have had your growth spurt

John.T

Alfie. I would check your current bikes top tube length again. 56.5 is very long for a 52cm frame unless it has a very sloping TT. I have a Ribble and a Trek with horizontal TTs. Both are 56cm centre to top and have 55.5 top tubes (centre to centre). To get the same length TT on the Willier you would need the XL size.
As said before the TT length is the most important as it is the least adjustable. Most modern frames are longer than there height until you get to the larger sizes so stand over is not really relevent.

a_n_t

not sure if it helps but i'm 6' 2" with a 35" inseam and I have the X large size mortirolo. Only thing i've changed is the 13 cm stem for a 12. fits me perfectly!

Alfie_T

I think I have posted the figures correctly but thegeometry for my current bike is on: http://www.specialized.com/bc/SBCGeomet ... spid=21575

Size 56 according to that chart has a 56.5cm top tube and an effective seat tube of 52cm.
My frame markings indicate a 56.5 cm tob tube but 56cm seat tube but the latter must be the virtual (I have just measured from the center of the crank to the point where the seatpost emerges from the frame and the center of that is 52cm).

John.T

Yes the 56 Allez has a 56.5 virtual TT and is 56cm to the point where it would meet the seat tube. That is if it was a horizontal top tube frame it would be 56cm C to top of the seat tube. If this frame fits you well then both the Williers would be too small as you would need stems between 2.5 and 4cm longer to get the same position. If your current stem is 10cm or less you could get away with the larger of the two.

Alfie_T

Thanks again John for the reply.

The 56.5 top tube did feel a bit stretched so I invested in an 90mm ITM Visia stem.

Actually on that note, the Specialized sizing chart for the Allez suggests the 56cm comes with a 120mm stem but mine (from Edinburgh Bike Co-op) came with a 110mm stem.

You don't think the standover height with the Medium Wilier's would be an issue?
Bearing in mind I usually always have my right foot clipped in and at the top of the pedal stroke when my left is disengaged.

John.T

The medium with a 11cm stem would be very close to your current bike. I wouild not worry about stand over. The frame is only 1cm higher than the Allez and that is at the seat post. It will probably be lower where you actually stand over it. More of a concern is head tube length and bar height. The Allez will have a longer head tube than the Wilier, probably in the region of 2 to 3cm, so you need to plan for this before you do any steerer cutting. Leave plenty of spacers on so you can put some above the stem until you are happy with the height. Then ride it for a while before finally cutting. I now leave a 5 or 10mm spacer above the stem. It looks OK and does give a little adjustment if needed.
Just looked at the Wilier web site. It has a slightly sloping and stepped down TT and is measured to the top of the seat tube so you will have no stand over problem.
Never the less it is still better to try one if you can. If you can not then check all the measurements against the Allez and see where the differences are. You can then see if you can replicate your current position easily or not.
The Wilier does look nice.

Steve I

Hi Alfie

I would say that your current frame is way too big for you. I'm 5' 10" and I go for a top tube length (effective) of between 545 and 555mm, give or take a mm or 2. I'm sure you'd be happier with a shorter top tube than me.

There's only 13mm difference in TT length between the 2 sizes you're considering, that's easily adjusted by swapping to a different length stem. Assuming you're happy with your current riding position, go for the medium. If you feel it's a bit too stretched, go for the small. Your current bike's reach is 565 (top tube) +90 (stem) =655mm, the medium new bike's reach would be 538+110 =648mm or 658mm with a 120mm stem. You could do the same calculations with the small size. Also consider handlebar height as a larger frame will have higher bars. Whereas you can lower the bars a bit by juggling washers, you can't get the bars any higher if they're too low other than by fitting a new fork and leaving the steerer long.

meagain

"I would say that your current frame is way too big for you."

Seconded. If inside leg (not trouser size!) is 31" then what is in trad terms a c.22" frame is BIG! I expect cries of "old fashioned git", but the rule of thumb of inside leg minus 10" for frame size remains a good starting point. With modern bikes I'd say minus 11" probably better - modern bikes tend to longer top tubes and you can re-gain the 1" via seat post adjustment.

Alfie_T

You are right in that my current frame is a little large for me and with the benefit of hindsight I would have probably opted for the 54cm Allez.

Steve, your point about the head tube is one of the issues leaning me towards the Medium. My current bike has a high headtube. To go from that to a Small Mortirolo with its 11.5cm headtube I think would require an ugly length of steerer protruding from the frame.
The Medium adds an additional 3cm to the headtube.