To sell a too large 'Horizon' or buy a smaller frame!?

General cycling advice ( NOT technical ! )
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531colin
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by 531colin »

REALLY??
This is Spa's own 54 cm set up for me, 5' 10". leg 33" to the floor measured like this http://www.spacycles.co.uk/info/leglength.php....How are you measuring your leg?

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LollyKat
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by LollyKat »

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Last edited by LollyKat on 10 Jun 2012, 11:44pm, edited 1 time in total.
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531colin
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by 531colin »

LollyKat wrote:............... Thorn Audax 525mm. ............ (mid-tube standover height is 738mm)..............


For anybody else struggling with the maths of this, Thorn size their frames on a "virtual seat tube"....the actual seat tube measures 425mm. (The virtual seat tube is with a virtual horizontal top tube.)
LollyKat
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by LollyKat »

I seem to have confused things again so have deleted my post.

Found this post which might be of interest:

EndlessWandering wrote:I've just ordered a 2011 Ultra Galaxy from Dryburgh Cycles, and the very helpful guy in the shop rang me after I placed the order to tell me the Dawes rep he deals with suggested I - at 5' 11' and with a 33" inside leg, so similar in height to yourself - go with a 53cm frame instead of the 58cm I had originally decided on, because the frame geometry has been altered for the 2011 Galaxy range and the 58cm is more like a 2010 61cm!
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horizon
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by horizon »

The 53cm would be the second largest in the range and right. The 58cm would be the biggest and would need to fit someone over six foot. It's much easier to look at the postion of the size in the range of four and then think: where do I belong if these four bikes fit everyone between 5' 2" and 6' 6"? That's 4" per size. 5' 11" is obviously size three.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
Ayesha
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by Ayesha »

Any confusion about frame sizes of OTP bikes, get yourself to a bike shop and stand over a bike. Sit on it and check KOPS and front spindle 'line on sight'.

If you are a million miles from a bike shop, phone a bike shop and ask them to measure the distance of centre seat tube to centre head tube with the tape measure horizontal. Then go on a bike sizing website and the website of the OTP bike manufacturer.

A bike manufacturer who don't give the frame geometry on their website isn't worth considering.
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by Ayesha »

Measure your Leg Length by the 'Sitting Height Ratio' method. It is less prone to error.

SHR is included in the calcs for 'Reach', along with 'Arm length' and 'Sturnal notch' height. ( which is the important dimension of the frame ).

Seat tube length is incidental. Thigh length and lower leg length contribute toward setting the seat tube angle to get KOPS correct when the saddle is in the manufacturers mid position.
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horizon
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by horizon »

Ayesha: there are four bikes to choose from and one person. They can measure until the cows come home but they can still walk out with only one of those four bikes. Back home they can start the tweaking and then what you say counts. People have this fantasy that they are being fitted to a bike - it just isn't lke that.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
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531colin
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by 531colin »

alpgirl wrote:I am 5'8'' with inside leg 31'' and sat on a 53cm Galaxy in a shop. Felt much too big. I was advised straight away to go for a 48cm. It has not arrived yet, so hoping it is the correct one for me!


horizon wrote:.......... there are four bikes to choose from and one person.........



I think part of the problem is Dawes current sizes are too far apart (5cm). When Spa started doing our own Touring bikes, we basically copied the steps of Dawes sizing of the time....3cm increments, I wanted a 54, so we had 51, 54, 57. We later added a 60cm, and a 48 cm bike with 26" wheels because the tiny Surly Long Haul Truckers with 26" wheels are so obviously "right".
Here http://www.spacycles.co.uk/info/pedaltosaddle.php you can get to photos of our (700c) tourers set with different saddle to pedal distances....I'm Mr average (5' 10", 31" trouser), 34" from saddle to pedal, I can get comfortable on 3 sizes of our bike, 51, 54, 57.
Alpgirl is a bit smaller than me, and would be an obvious candidate for a 51cm bike.
Our 48 bike has 26" wheels, its "tiny but perfectly formed" like the LHTs. Its right for somebody 5 feet tall.
Dawes 43 and 48 cm bikes have 700c wheels, and I think its wrong for those frame sizes.
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by Malaconotus »

The nominal sizes of the main brands of OTP tourer are a confusing mess. The below shows Raleigh, Dawes, EBC Revolution, Spa, Ridgeback, and Surly listed in order of top tube length. Bikes with completely different nominal sizes sit adjacent, but even that isn't the whole story. Few manufacturers quote a full list of all the relevant geometry measurements. I noticed this morning while sizing a customer on a Country Explorer and a Ridgeback Voyage, both nominally 58cm, that the Ridgeback stem is around 30mm longer.

Click on image to enlarge and make legible...
Tourer Geometries Compared ii.JPG
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531colin
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Re: To sell a too large 'Horizon' or buy a smaller frame!?

Post by 531colin »

Thats a lot of data to collate!

Unfortunately, the top tube length is not the whole story.
The reach from saddle to bars is governed by the length of top tube in front of the BB.
How much top tube there is behind the BB will not alter reach, assuming the cyclist sets their saddle a particular distance behind the BB.
Take a frame size of 50cm. and a seat tube angle of 72 deg.. Altering the seat tube angle to 74 deg. will shorten the top tube about 17mm, but will not alter the reach one jot if the cyclist sets their saddle a particular distance behind the BB.
So why do so many manufacturers use steep seat tube angles on small sizes?
I think its a way to get the right numbers into the geometry table, but I don't see how it helps anybody to get comfortable on a bike.
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