if having to buy a bike on frame measurements alone, whats MOST important?

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Jamesh
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby Jamesh » 26 Jul 2020, 6:33pm

I'd have thought 22" would suit a average 5ft10 guy like me.

Older generation tended to ride bigger frames whilst young racers ride smaller framed bikes....

Cheers James

fastpedaller
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby fastpedaller » 26 Jul 2020, 6:45pm

martinn wrote:Have seen that the Spa Mono is now back in stock, and have permission of finance to make a capital purchase.

I live very far away from Spa, certainly not close enough for a quick visit, and the nearest outlet for Spa to me, only has a single Spa in their shop, (Which is too small for me)



Ooh that Spa Mono does look good :D
I bought a Spa tourer 6 years ago - one of my best purchases! I also live far away from Harrogate, and decided that money spent on train/car/maybe stay overnight would be pointless - if I really didn't like the frame I'd sell it on and probably be no worse off financially. I did the same, comparing to bikes I had and the spec to make the decision. As Brucey's list above, and unless you want a lot of spacers or are ok with a 'slammed' stem pay attention to how low the headtube will be on the smaller frame c/f larger one.

mattsccm
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby mattsccm » 26 Jul 2020, 7:27pm

Colour :D :D

bazzo
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby bazzo » 26 Jul 2020, 7:43pm

That’s about me Mick, I ride a 56cm or 22Inch.

martinn
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby martinn » 26 Jul 2020, 9:38pm

thanks for all the advice,

I looked at stack and reach, and found a calculator which i could compare three bike shapes as outlines.
I put the info I had on the spa Audax 56 and 58 in, and initially compared them with the Terra C, but I found that i had to make a guesstimate on the fork size, but i knew the stack and reach for the frame for this bike. interestingly, this was much bigger than my current audax bike on the pictograms, but its also very comfy.... wasn't quite expecting that

I then put the measurements in that I had taken off my Rourke, which is very comfy for long distance.
The reach was not far off either way, but i need to put a 120cm stem on the 56cm or a 110 cm stem on the 58cm.
But the stack on the 56 was a much closer match, i would have to "slam" the stem of the 58 to get a close approximation of the stack

So i think in this case I will try the 56cm,

Next question, what colour! Black, to match the fork or a metallic bronze...
if black then the rest of the colour choice is easy (for me) silver or black components, but Bronze, can you get bronze bar tape?

then Carbon or Steel fork, i would be inclined to go with the steel except in the images it seems to have many bosses on it which as I will be running a standard drop rim brake, are a bit, for me superfluous, and i don't like the look of them

Does anyone have a Spa steel fork, or a better picture than the one on the website?

thanks

Martin

fatboy
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby fatboy » 26 Jul 2020, 10:14pm

Seat tube angle. I don't get stack and reach as it ignores where you sit relative to the pedals. IMHO if you can sit and pedal comfortably without too much pressure on your hands the rest can be sorted with stem length and height (with spa you'll get a long steerer so lots of options there).
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly

De Sisti
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby De Sisti » 27 Jul 2020, 11:21am

Brucey wrote:seat tube angle, ETT, head tube height above BB, in that order. Then other stuff like BB drop, front centres, etc.
cheers

How does the person on the street looking for a bike measure seat tube angle? Is there a specialist tool
for it in bike shops?

Head tube height above bottom bracket? I've not heard of that one before.

slowster
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby slowster » 27 Jul 2020, 1:16pm

martinn wrote: i would be inclined to go with the steel except in the images it seems to have many bosses on it which as I will be running a standard drop rim brake, are a bit, for me superfluous, and i don't like the look of them

Does anyone have a Spa steel fork, or a better picture than the one on the website?

The steel fork for the Audax Mono is 725, whereas the steel road fork which Spa sell separately, but describe as suitable for use on their Audax bikes, is "quality cro-mo". That suggests that the 725 fork is new, and I suspect that it might not have the rack bosses.

fastpedaller
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby fastpedaller » 27 Jul 2020, 1:27pm

slowster wrote:
martinn wrote: i would be inclined to go with the steel except in the images it seems to have many bosses on it which as I will be running a standard drop rim brake, are a bit, for me superfluous, and i don't like the look of them

Does anyone have a Spa steel fork, or a better picture than the one on the website?

The steel fork for the Audax Mono is 725, whereas the steel road fork which Spa sell separately, but describe as suitable for use on their Audax bikes, is "quality cro-mo". That suggests that the 725 fork is new, and I suspect that it might not have the rack bosses.


It all looks a bit vague...... I'd ask Spa directly.

rfryer
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby rfryer » 27 Jul 2020, 2:15pm

De Sisti wrote:
Brucey wrote:seat tube angle, ETT, head tube height above BB, in that order. Then other stuff like BB drop, front centres, etc.
cheers

How does the person on the street looking for a bike measure seat tube angle? Is there a specialist tool
for it in bike shops?

Head tube height above bottom bracket? I've not heard of that one before.

Most of these details are quoted by bike manufacturers.

If you want to check a bike you own, you can do worse than taking a photo of the bike, square on, with a long focal length, and taking measurements from that.

scottg
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby scottg » 27 Jul 2020, 2:16pm

De Sisti wrote:How does the person on the street looking for a bike measure seat tube angle? Is there a specialist tool
for it in bike shops?


For smartphone users, Stanley angle finder app.
+++++++++++++++++++++++++++++++++++++
Why not the best, buy Cyclo-Benelux.

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NATURAL ANKLING
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby NATURAL ANKLING » 27 Jul 2020, 3:58pm

Hi,
whoof wrote:If I had to pick one place to measure it would be effective top tube length. I've had bikes ranging from about 42 to 56 cm but the effective top tube on them only ranged by about 0.5 cm

This is the most important dimension, considering that top tubes are very commonly sloping, hence virtual effective as said.
Next for me would be wheel base.
Both are very dependant on your size and your riding style.
I am similar height to the OP, but have long body and arms in proportion so I need a good reach, TT on the road (old fashioned 80's) and tourer (90's) come in at 575mm (22 & 5/8") with 110mm stem, but I also point toes at bottom of stroke (only) so I still need good height, sole of shoe to saddle centre needs a good 915-920mm, so ST 600mm (23 & 5/8").
I can see others using a smaller frame.

Next to seat height...too low.....bars too high........a too small a frame must be next to what I would fix on a fair few riders I see, but if you can ride it then who am I to say.
Frame hence reach to bars too short will make you sit up and back ache comes next IMO :)
NA Thinks Just End 2 End Return + Bivvy
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De Sisti
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby De Sisti » 27 Jul 2020, 4:05pm

rfryer wrote:
De Sisti wrote:
Brucey wrote:seat tube angle, ETT, head tube height above BB, in that order. Then other stuff like BB drop, front centres, etc.
cheers

How does the person on the street looking for a bike measure seat tube angle? Is there a specialist tool
for it in bike shops?

Head tube height above bottom bracket? I've not heard of that one before.

Most of these details are quoted by bike manufacturers.

If you want to check a bike you own, you can do worse than taking a photo of the bike, square on, with a long focal length, and taking measurements from that.

Take measurements with what, a pertractor? :lol:
Trial and error for a punter to find out what seat angle suits them.

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531colin
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby 531colin » 27 Jul 2020, 5:27pm

Seat tube angle is my "must be right" number. It governs how much difficulty you will have in getting the saddle far enough back, or even if that will be possible at all.
ETT and reach are both next to useless without seat tube angle.
Stack is only "the height of the top of the head tube above the BB"...per. Brucey.
For frames designed for dual pivot sidepull brakes there can't be very much variation in fork length; therefore head tube length is a reasonable proxy for stack.

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531colin
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Re: if having to buy a bike on frame measurements alone, whats MOST important?

Postby 531colin » 27 Jul 2020, 5:44pm

Spa website used to have pictures of me riding a 54cm bike; at that time I was about 5'10" and I basically designed the 54 for me. (have subsequently shrunk, but thats mainly intervertebral disc compression, and doesn't alter bike size)
So 56 for somebody a bit taller sounds about right. Ett will be about 10mm more, no big deal.