Newbie with geometry questions.

rich_p

Hi all,

I’m new to the forum. I have recently decided I need to try and get fitter and actually do some exercise so have started biking again in the evenings.

I want to try and understand frame geometry on bikes as I fancy a new one, there’s nowt wrong with my current bike but we all like new shiny stuff don’t we!

I have found some guides on what to look out for but want some real world advice to help me.

I have an early 2000’s Carrera gryphon which started off as a hybrid but I added some Manitau front shocks and mtb tyres a few years ago.

The bike itself fits me very nicely and I’m quite comfy on it with no areas of my body feeling more fatigued than anywhere else. It copes with tracks along rivers and canals quite well but once we start going across grass and slightly rutted fields it shows up that it’s not a true mtb.

I have been into shops and tried quite a few different frames and sizes. It’s amazing how different manufacturers sizing differs so much isn’t it.

The most comfy so far is a medium sized Cannondale SL. I quite like the look of Whyte bikes and tried those too.

The medium Whyte although probably more than useable felt a little big but they didn’t have a small. They had a ladies 802 model which I’m told is ever so slightly shorter than the small so tried that.

It felt ok if not a little cramped and my weight was forward but the guy said with the extra size of small it should be about spot on and I looked more at home on that then the medium.

Now here’s the question, my friend has an 08’ cinder cone in an 18” frame. When measured next to my bike the effective top tube length is pretty much the same (his top bar is far more slopped than mine so that why we checked the ett) and the stem seems to be a similar length too . If I ride his bike I feel really upright and really quite cramped. The main difference I can see is the bars. He has the standard mtb riser bars and I have flat bars on mine.

Can the bars really make that much difference or could it be part of the frame design that causes me to be so much more upright and cramped on his than I am on my current bike?

If it’s frame design it would be helpful to know what features to look out for in a new bike that will give me a similar riding feel to my current one.

Thanks

The Rookie

Yes the bars can make that much difference, riding postion is all about the 3 contact points (saddle, pedals and grips) move one and you change the seating position.

To get a similar feel, you need the points in a similar relaticve positions, sounds like you need an XC style bike, so a Rockrider 8.1 (£550 from Decathlon) would be my first suggestion.

Budget?

My commuter is a Gryphon, they are quite a stretched out bike. Also setback or inline seatposts and saddle position within them change the cockpit length, so 2 bikes with the same effective toptube and stem lengths can be upto about 2.5" apart in cockpit length, that's without backswept versus near straight bars which can dial in another 1".

jairaj

Rich_p wrote:

... effective top tube length is pretty much the same ...

In certain areas something small like 20mm can look like a very small change but feels quite big. Also if a few measurements are slightly different then they can all combine together to make something that feels very different.

rich_p

Thanks for the replies.

Budget was originally around £700 as that was what I was going to pay for a Whyte 801.
(Less if I choose to do the cycle scheme)

The snob in me makes me cautious about the RR8.1 but it does seem to have good feedback after a search on the net.

I have another option though. Just found out I can get 25% discounts on Scott bikes.

I can see the aspect & scale bikes but am not sure why I would choose one range over the other, both have £700 bikes which would drop down nicely with the discount.

jairaj

The Scale range is more towards XC racing, so steeper angles, longer geo. The Aspect is more of a trail bike , slacker angles and more relaxed geometry.