So, if you were looking for a new bike and you found yourself “between sizes”, would you rather have a slightly short top tube and then slap on a layback seatpost/longer stem or get a slightly longer top tube and shorten the stem?

I was in that position and went for longer T/T, then just dialled it in with a shorter stem.

Longer top tube. Always.

Always longer top tube.

Unless standover is an issue of course – I had to go shorter on my Genesis because I simply couldn’t stand over the 19″ without ‘contact’

I’m in exactly the same position… small or large Genesis Alpitude? Think i will probably go for the larger one. Its much easier to ‘shorten’ a bike and in some cases this improves handling. Would hate to be too cramped on a bike.

Ben, what size Alpitude is your longtermer?

I’m 5’10” and once bought a large frame just so I could run a 70mm stem on it but still gte a good reach. Longer toptube and short stem. Most bikes have relaxed angles now. if you get the shorter one and correct over the back of the bike it will feel a bit odd.

Sort of depends on what the bike is for – longer for general riding, perhaps shorter for playing on.

However, as mentioned above, shortening a bike with a shorter stem is usually better than lengthening with a long stem.

Don’t buy a bike that doesn’t fit!

love shorter tt,, i should ride 17″ marin and whyte bikes but prefer 15″ bikes maybe coz i am an old bloke i like sitting up with less weight on my wrists

The difference is going to be 1/2″ max (from “ideal” to either size) I’d guess – do you think it really matters that much?

I’d go longer.

between sizes? look at other frames

I think the fit of a bike is perhaps the most important factor

RichieBoy I’ve got a solution for you

“I’m in exactly the same position… small or large Genesis Alpitude? “

Just checked and these frames come in S, M, L ,XL. So why not go for the medium.

Shorter (if that’s possible). I’ve run a 50mm stem for years so I reckon having a longer t/t and shortening the stem is not an option 😉

Shorter. If you go longer you are generally reducing the standover and increasing the wheelbase, which just makes the bike feel too big and unwieldy.

scu98rkr… Alpitude comes in 2 sizes 16.5 (small) and 18.5 (large) think you’ve been looking at the altitudes

There’s only 14mm of difference in the top tube lengths between the 16.5 and 18.5 Genesis Alpitude frames. A difference that can be VERY easily recitified either way by a stem change.

What’s more important here, considering the type of bike it is, is the standover clearance. Personally, even at 5ft 11, I wouldn’t want to be riding the 18.5 as things might get a touch close! I have a 17.5″ Altitude, and though the 19 would probably have fitted a bit better (again, only a 15mm TT length difference though), I just slide the saddle back on the rails by 10mm, but I’ve got loads more nad clearance!

Thanks mboy i reckon i will take the plunge on a 16.5, it is certainly the size everyone is pointing me towards. Thinking about it, its only an extra inch of seatpost and like you say stems can be swapped!

Richieboy – My Alpitude is 18.5in. I’m 6ft 1in and would prefer a very slightly longer top tube.