Stuck between frame sizes

Bozman

I've just been looking at buying a new frame but size wise I'm stuck between the small and medium.
The small has my usual TT length but due to the geometry of the frame(long TT, short seat tube and head tube) this will leave me with a very aggressive riding position, I don't like a sportive fit but the small is barmy.
The medium has my usual seat tube and head tube length and generally measures up to my normal ride, but the TT is 2cm longer than I'm used to.

So.... will I notice the difference in TT length and will it be easy to lose or just ditch the frame and start looking again.

smidsy

You could potentially fit shorter reach bars and stem to assist. Ultimately without actually trying one for a proper period of time it is a gamble.

Sounds like it may not be the frame for you if you are having to compromise too much.

sloppyschleckonds

Go too big and it rides like a plank of wood.
Go too small and you'll need a longer stem to get a semi decent aero position.

Basically buy the one you like the look of and be done with it.

denniskwok

Given the choice, go for the smaller frame. The headtube can be used with spacers and nothing wrong having a fair bit of seatpost showing. But, if the bike don't fit, then it just don't fit and you should look for a different frame.

smidsy

SloppySchleckonds wrote:

Basically buy the one you like the look of and be done with it.

There seems to be a theme with you lately

Pooter

Dismiss the model/brand completely and find a frame that does fit you properly. There are hundreds to choose from.

rolf_f

Pooter wrote:

Dismiss the model/brand completely and find a frame that does fit you properly. There are hundreds to choose from.

This - rather obviously!

Bozman

Rolf F wrote:

Pooter wrote:

Dismiss the model/brand completely and find a frame that does fit you properly. There are hundreds to choose from.

This - rather obviously!

That's where I was going but you know what It's like when you want "that" frame, you don't get many Argon 18s about and I was looking for something a little different in the price range of a gallium pro.

neeb

You really do need to pick the model of frame for having a geometry and size that fits you, not decide on the model and then look at the geo and sizes.. Think of it as the intelligent way to go custom - instead of paying to get someone to build the perfect fitting frame for you, you need to search for an off-the-peg frame that fits you perfectly.

First thing I do when a new frame is launched is look at the geo charts. About 60 or 70% of models won't fit me perfectly, so I rule them out immediately.

Raffles

would the OP be in the 5ft 8 - 5 ft9 ballpark ?

neeb

Raffles wrote:

would the OP be in the 5ft 8 - 5 ft9 ballpark ?

Yeah, I'm not the OP but I'm 5'9" and I'd be in-between S and M too. I could fit on the M, but only with a 100mm stem (which while acceptable, isn't perfect).

Bozman

neeb wrote:

Raffles wrote:

would the OP be in the 5ft 8 - 5 ft9 ballpark ?

Yeah, I'm not the OP but I'm 5'9" and I'd be in-between S and M too. I could fit on the M, but only with a 100mm stem (which while acceptable, isn't perfect).

I'm 5' 9.5". I've always ridden a 53/54 TT with a 100mm stem but unfortunately it isn't to be this time, pity because I was set on one but we all know how much geometry varies with brand, I've probably just been lucky.

Raffles

the height range I mentioned can be a pain in the arrse when it comes to bike fit, the 52 has a very usable top tube length but the head tube is really short and makes the bike really aggressive, the 54 has head tube size which fits nicely but if you have shorter torso then the top tube length is the biatch.

im 5 ft 9 myself but I have a short inseam of 30 inches , a bike fit came to the conclusion my ideal bike fit is 543mm top tube and seat tube of 520mm. as it happens the caad8 is 545mm top tube and seat tube 520mm, I use mine with a 100mm stem and the fit is just fine, 5 ft 6 - 5 ft 7 gives a great fit on a 52 and 5 ft 10 gives a great fit on a 54 , its just that 5 ft 8 - 5 ft 9 range which can be a stuck in no mans land body sizing.

neeb

Remember when you are looking at effective top tube lengths to correct for seat tube angle. Assuming you are setting the saddle position relative to the BB, a 74 degree seat tube angle makes the reach about 1cm longer than a 73 degree seat tube angle for the same effective top tube length.

So 73 STA + 55.5cm ETT very approximately equals 73.5 STA + 55cm ETT, which very approximately equals 74 STA + 54.5 ETT. The correction factor is usually actually a tad more than 1cm for every degree of STA for a mediumish size frame, but it's not far off.

I'm forever pointing this out in threads on bike sizing because it's something most people seem to be unaware of.

Raffles

A lot of sources place a lot of weight on the importance of top tube length, but I firmly believe that that head tube length is the little runt in the family that shouldn't be underestimated. Ive ridden bikes with top tube lengths that were very comfortable for me but also had the most back breaking and neck stiffening head tubes, when I had a short run on a giant tcr it felt like I could smell the front tyre as the front was so low. Frame sizing is sadly a tad fickle and intimidating for the new to road cycling rider;

Is the top tube too long / short
Is the head tube too low / tall
Is the seat angle too slack / aggressive
How much toe overlap will there be if wheelbase is too short
Should the front hub be blocked out when Im at the hoods or in the drops

Add to all this an intimating shop for the noob, kind of like somebody who owns a sanyo music system walking into a high end hifi retailer who sells SME turntables and deParavicini amplifiers and literally being scared stiff about making a purchase . The list of things to be seriously uneasy about now comprises of:

First date
First kiss
Getting married
In-laws calling round when wife is out
Walking into specialist hifi store when you aint got a clue
Having limited budget and walking into a shop which sells road bikes
Selling that road bike because bike you bought fit was totally wrong
Saving up for another road bike to replace that 1st road bike......................and so it goes on.

styxd

Don't bother with the medium, it sounds like it'll be too big.

Just buy a frame that fits you, if the headtube is too short, then get a frame with a headtube that's long enough for you. Its hardly rocket science (or is it?)

Raffles

OP , do check out Jamis bikes (ventura is nice ) as their sizing takes into account slightly shorter top tubes with raised head tubes which for somebody your height I think would be very comfortable.