Frame Geometry

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SpokeyDokey

67, & my GP says I will officially be old at 70!
Moderator
Epic cycles will let you test ride to your hearts content

I know there are a few out there but they are mighty thin on the ground ime.

Shropshire is too far from Cumbria for a bike test ride for me. :smile:
 

Fab Foodie

hanging-on in quiet desperation ...
Location
Kirton, Devon.
I have already read some articles on fitting. They are all very knowledgable and everything but they tend to fit a bike to you (crank length, seat height, seat position, handlebar width, ...). They all say that reach and stack and some angles are important, but they don't say exactly in which way they are important.

Looks like I should go for a shorter reach, bigger seat tube angle, probably smaller head tube angle, and maybe a shorter stem? Good luck to me. Thanks again for all the ideas.
Regarding your first point; that's why I like the Peter White article as it talks more about comfort in an understandable way.

Regarding the second point, I think you may want a less steep seat-tube angle. To take the weight of your hands your upper body needs to be counterbalanced. If you consider that your feet position is fixed by the cranks, your backside is then the counterbalance to your torso and arms. Stand upright and sideways up against a door frame, us you bend forward of the door frame (without moving your feet) then your backside has to move in the opposite direction beyond the door frame. It should be like this on a bike if you fit for comfort. You should be in such a position that you can pretty much take your arm off the bars and maintain body position.

I have short legs and a long back and had a frame custom made by Rourke, however they misunderstood (or didn't heed) my initial requirement which was to have a really laid back seat-tube so the seat would sit back further than normal to counterbalance my longer torso. So they did the bike fit and designed how they wanted (based on years of professional experience) rather than how I wanted it.
The bike was great, but wrong, I could see as soon as I set eyes upon it. They had used their standard seat-post angle and TT lengths based on their fit data. Being good sorts they let me take it away and run it a while just to be sure (and I was).
So I went back with the bike and a seat post on a broom handle to show them the angle I wanted the seat-post and Brian Rourke himself came along to make sure all was in order. To be fair we had a pretty robust debate about the fit and my requirements and it wasn't until Brian got aboard his own bike with hands on the hoods and then just took his hands off the hoods by a cm and remained planted in the seat .... BINGO! I did the same thing on the bike they made and I fell forward off the seat, we then understood each other. I needed the seat further back than 'standard' so a very laid back seat-tube angle. I got out the seatpost on a broom handle, we measured the angle and figured-out where to insert the extra 4cm of top-tube (2 at the satpost end and 2 at the heat-tube end)!! They scratched their heads and said they'd build it for free as long as their was no come back. Fair enough. It fits perfectly, to the mm. To the untrained eye it looks pretty normal.

From this:

IMG_1446.JPG



To this:
IMG_2987.JPG


To get the longer reach with the same stem length, the seat-tube has gone back 2cm where it joins the top-tube and the head-tube has gone forward 2cm where it joins the top-tube. So I have the long reach I need BUT I'm sitting 2cm further behind my feet (the bottom bracket) to remain balanced. I can take my hands off the hoods and not slip forward, meaning on a long ride I don't have a lot of pressure on my arms and hands!

OK, long story BUT, in your particular case, you need to have a bike set-up where you can get that comfortable position with your amount of flexibility and reach. A good shop should be prepared to do a basic fitting exercise before you test-ride.
 
OP
OP
J

juliensorel

Member
Regarding the second point, I think you may want a less steep seat-tube angle. To take the weight of your hands your upper body needs to be counterbalanced.

Of course you're right. I will strikethrough what I typed in that post and make a notice 'corrected by Fab Foodie' the moment I find out how to edit my posts.

As for the story, I cannot say I've had much experience with bike shops, but even I've noticed that they want to sell the bike they want to sell rather than the bike you want to buy. I know I cannot rely solely on numbers. But I want to have at least a very basic understanding of how many cm is considered short for reach, or head tube, or what angle is considered steep for seat tube angle.
 

SpokeyDokey

67, & my GP says I will officially be old at 70!
Moderator
Of course you're right. I will strikethrough what I typed in that post and make a notice 'corrected by Fab Foodie' the moment I find out how to edit my posts.

As for the story, I cannot say I've had much experience with bike shops, but even I've noticed that they want to sell the bike they want to sell rather than the bike you want to buy. I know I cannot rely solely on numbers. But I want to have at least a very basic understanding of how many cm is considered short for reach, or head tube, or what angle is considered steep for seat tube angle.

Apart from one shop out of six all have tried to sell me a bike that I didn't want, instead of one I did want, simply because they had the one I didn't want on the sales floor. Bit desperate.

How about a 60 year old recreational cyclist (me) looking for a chubby tyred endurance bike being suggested that the CAAD10 that happened to be in stock was 'ideal' for me. Haha - pathetic really. I go on about cycle shops a bit but really, most I have been in are a crock of crap when it comes to service and good, honest advice.
 

Fab Foodie

hanging-on in quiet desperation ...
Location
Kirton, Devon.
Apart from one shop out of six all have tried to sell me a bike that I didn't want, instead of one I did want, simply because they had the one I didn't want on the sales floor. Bit desperate.

How about a 60 year old recreational cyclist (me) looking for a chubby tyred endurance bike being suggested that the CAAD10 that happened to be in stock was 'ideal' for me. Haha - pathetic really. I go on about cycle shops a bit but really, most I have been in are a crock of crap when it comes to service and good, honest advice.
Sad .... But so true unfortunately ....
A friend has recently had the same experience, wanted something sturdy and flexible and kept being steered towards racier stuff. In the end be bought a Dawes Galaxy touring bike which fits his needs perfectly.
Unless you are going on really rough stuff a tourer is option.
@juliensorel a more touring orientated machine might be worth considering generally allowing a more upright riding position and more comfortable and stable riding position. Just a thought!
 
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OP
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juliensorel

Member
@juliensorel a more touring orientated machine might be worth considering generally allowing a more upright riding position and more comfortable and stable riding position. Just a thought!

I have bought a Fuji Sportif 2.1 today. 54cm frame size. The salesperson actually listened to me and didn't object when I asked for the shortest stem they had (6 cm instead of 10cm). With the bars flipped upwards, my sitting position is probably as good as it gets. Maybe there's better out there, I don't know. We're in the second half of April, how long would I consider and compare charts and ... anyways.

I'm glad I opened this thread. Thanks for all your pointers.
 

Fab Foodie

hanging-on in quiet desperation ...
Location
Kirton, Devon.
Gl
I have bought a Fuji Sportif 2.1 today. 54cm frame size. The salesperson actually listened to me and didn't object when I asked for the shortest stem they had (6 cm instead of 10cm). With the bars flipped upwards, my sitting position is probably as good as it gets. Maybe there's better out there, I don't know. We're in the second half of April, how long would I consider and compare charts and ... anyways.

I'm glad I opened this thread. Thanks for all your pointers.
good that you're sorted, let us know how you get on :-)
 
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