New Bike Geometry Questions

ashnorman

Im planning to buy a new bike in the next couple of months. Ive had a Merida Road Ride 77 for about 5 years from when I first started cycling. Ive now done enough miles on it and have enough saved to feel I warrant a new bike. Im looking for something slightly more aggressive in terms of the cycling position as Ive started doing triathlons but still want something comfortable for longer rides. Being 6'4", not many bike shops have a large selection of bikes in my size to test (typically 61cm) so they will typically order one in for me to try. I don't want to waste all their time ordering in loads of different bikes so am trying to pre-empt this slightly and identify bikes that may be the right fit for me based on their geometry. From what I can pick up on the net, the most important things to consider are stack, reach, top tube length and head tube length. How much is actually going to make a difference? Im also considering a bike from Rose which is another reason for this question since they are online only.

Ive listed the two bikes I'm currently considering below along with the dimensions I mention above and those of Merida's current offering which compares to my current bike (cant find the road ride 77 on the net now).

Merida Ride 100 (Stack 658 / Reach 404 / TT Length 605 / HT Length 250)
Specialised Tarmac Comp (612 / 408 / 601 / 210)
Rose CRS XLite (600 / 412 / 596 / 200)

The difference in the Stack and Head Tube lengths is quite significant, ultimately meaning a more aggressive position (I presume?). Any thoughts on how much of a difference this will feel like. I assume I can add spacers to effectively increase the head tube length?

Ash

keezx

As you have 5 years expirience with your current bike it makes sense to compare your wish-bikes with your current one , i.e. top tube and head tube.
Should'nt be too difficult to measure those sizes.