Standover measurement

General cycling advice ( NOT technical ! )
reohn2
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Re: Standover measurement

Postby reohn2 » 30 Mar 2013, 9:22am

ron2old
Are you getting toe overlap with your present bike?
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ron2old
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Re: Standover measurement

Postby ron2old » 30 Mar 2013, 11:31am

531colin I followed advice about getting saddle setback right first by using the KOPS method and found this made all the difference to the feel of my bike to the better and don't really want to change that. I then tried several stems to get my reach right and ended on the 12 or 13 and finally chose the 12 because I think (just a feeling I don't actually know) that the long stem contributes to the skittish feel of the steering that I would choose the shorter of the final two. Any shorter stem and I get neck and arm ache. The bike set as it is now is the most comfortable since I've had it and I've done a few 100km rides on it with no discomfort. Although something intuitively nags at me to tell me it's not quite right. I also think it never will be. I think the top tube is very short at 525 which gives me the feeling that the frame is too small for me but in actual measurement it's not with 50cm seat tube being right for my height of 66". I worry about spending another £100 - £150 on a bike fit because that's money I could put towards a new bike and if I went to three different fitters I would get three different results. My bike is not a road bike but classed as a cyclocross come commuter bike and that might be where the problem lies. It might also be a compact frame, not sure and don't know what compact frame means either.

ron2old
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Re: Standover measurement

Postby ron2old » 30 Mar 2013, 11:34am

Reohn2 I will check for toe overlap when I cycle to work tonight. Haven't noticed but I have a short front mudguard that doesn't come down far enough for that to be a problem. But will check tonight to see if that would have happened with a normal full length mudguard on.

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531colin
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Re: Standover measurement

Postby 531colin » 30 Mar 2013, 12:04pm

shouldn't get overlap with 610mm front centres.
the 54 Trek that you are looking at gets a longer top tube by pushing the seat back, (relative to the BB) not by pushing the bars forward....look at the seat angles.
Your current bike is very stable steering...almost any other bike will be livelier.
People say a long stem gives sluggish steering....its not true, but it certainly wont make it skittish.
Road bikes strive for a short wheelbase, which normally means short top tube.
Spas 50cm audax has 541mm effective top tube, but that's mostly due to a slacker seat angle 72.5deg......the usual problem with small bikes is getting them short enough. ....the 54 trek actually has more reach in front of the BB than the Spa

ron2old
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Re: Standover measurement

Postby ron2old » 30 Mar 2013, 11:03pm

Well I've arrived at work and definately no toe overlap not by a long way thanks.

ron2old
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Re: Standover measurement

Postby ron2old » 30 Mar 2013, 11:13pm

Here are some photo's (I hope) of my set up which is comfortable for me. The seat is setback/forward to give me 100% KOPS. The stem is a 12 (got 5 stems in my box now) reach obtained by elbow on nose of saddle to fingertips + 3cm. All of this setup malarky obtained from this forum and different threads and conversation's resulting in my most comfortable set up to date. Can't help feeling that the frame is just slightly too small for me when riding the bike but a 50cm seat tube is the correct lenght for my 66" height apparentaly.
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ron2old
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Re: Standover measurement

Postby ron2old » 30 Mar 2013, 11:21pm

Forgot to mention I changed my saddle from my brooks B17 to the Fizik Arion in the photo's because the Arion has extra long saddle rails to allow me to get KOPS. Such a good decision because obtaining KOPS has allowed me to be comfortable. It was impossible to get anywhere near KOPS with a Brooks saddle.

reohn2
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Re: Standover measurement

Postby reohn2 » 31 Mar 2013, 12:01am

I didn't think you'd have t/overlap.
The stem in the photos doesn't look like a 120mm to me :?
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ron2old
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Re: Standover measurement

Postby ron2old » 31 Mar 2013, 12:27am

Bought the stem on E Bay advertised as a specialized 12 for £10.50. It's got no size numbers written on it I'm just going by what it was sold as. I'm going to have to find a tape measure and measure it now! Can I just confirm that I should measure from the middle of the handlebars back to where the headset bolt is. Better do it when the wife's not looking she already thinks I have a problem.

ron2old
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Re: Standover measurement

Postby ron2old » 31 Mar 2013, 12:37am

Reohn2 can I just ask your opinoin of the photo's. Do you think the saddle looks too far set back and the stem too long or is it just me. I thought if I reduced the seat angle from it's current 75 to maybe say 73.7 (Trek 54cm) it would move the saddle further forward on it's rails to a more normal middle of the seat position. Then lenghthen the top tube to say 540 (Trek 54cm) I could still put my elbow to the saddle nose + 3cm and have a shorter more normal stem whilst maintaining KOPS and the correct seat tube lenghth for my height of 50cm. I'm talking myself into this are'nt I? The problem would be talking the wife into it!

Ayesha
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Re: Standover measurement

Postby Ayesha » 31 Mar 2013, 8:46am

Where's your Knee Over Pedal Spindle?

On a tourer, adjust the saddle fore/aft so the VERY front of the knee ( skin in front of the Patella ) is over the pedal spindle.
( I hate it when people spell it 'Peddle spindal'. )

Buy a stem which causes your Lumbar Vertebae to be at 45 degrees.
When you sit on the bike ( riding normally with the hands on the handle grips ) glance down and the front wheel spindle should be hidden behind the handlebars.

Raceboys have KOPS differently. They have the rear of the Patella over the peddle spindal. Some have the centre of the knee over the peddle spindal.

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531colin
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Re: Standover measurement

Postby 531colin » 31 Mar 2013, 9:55am

ron2old wrote:Reohn2 can I just ask your opinoin of the photo's. Do you think the saddle looks too far set back and the stem too long or is it just me. I thought if I reduced the seat angle from it's current 75 to maybe say 73.7 (Trek 54cm) it would move the saddle further forward on it's rails to a more normal middle of the seat position. Then lenghthen the top tube to say 540 (Trek 54cm) I could still put my elbow to the saddle nose + 3cm and have a shorter more normal stem whilst maintaining KOPS and the correct seat tube lenghth for my height of 50cm. I'm talking myself into this are'nt I? The problem would be talking the wife into it!


Ron
54 Trek effective top tube 542
SML Arkrose.....525
Difference...17mm,
BUT, most of that extra top tube is going into moving the seat lug back
(you can do the math., if you like.....75 deg minus 73.7deg is 1.3 deg...so the seat lug moves back in an arc of 1.3 deg. the radius of the circle is 500mm, ie. BB to seat lug.).
....I make it the seat lug moves back 11mm,
That gives you a whopping 17 minus 11 = 6mm shorter stem for the same riding position....ain't worth it, mate!.
The 54 Trek also has a 30mm longer head tube than your current bike, possibly compromising handlebar height and standover.

Roadies are obsessed with short wheelbase, which means short top tubes (usually)
You might be better looking at audax type bikes, which have clearance for bigger tyres and mudguards, therefore longer top tubes.
OR...just ask the forum...new thread.....what bike has a long top tube for somebody 5' 6".??

reohn2
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Re: Standover measurement

Postby reohn2 » 31 Mar 2013, 10:31am

531colin wrote:Ron
54 Trek effective top tube 542
SML Arkrose.....525
Difference...17mm,
BUT, most of that extra top tube is going into moving the seat lug back
(you can do the math., if you like.....75 deg minus 73.7deg is 1.3 deg...so the seat lug moves back in an arc of 1.3 deg. the radius of the circle is 500mm, ie. BB to seat lug.).
....I make it the seat lug moves back 11mm,
That gives you a whopping 17 minus 11 = 6mm shorter stem for the same riding position....ain't worth it, mate!.
The 54 Trek also has a 30mm longer head tube than your current bike, possibly compromising handlebar height and standover.

As ever,spot on! :)


You might be better looking at audax type bikes, which have clearance for bigger tyres and mudguards, therefore longer top tubes.

Or stick with what you've got for at least a few thousand miles.

The stem you have fitted should be measured CtoC on the lower side as you have it fitted to the bike in the photo.
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reohn2
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Re: Standover measurement

Postby reohn2 » 31 Mar 2013, 10:41am

Ayesha wrote: the front wheel spindle should be hidden behind the handlebars....


This has come up before and it's a myth.
It all depends on toptube length and stem length as to where the rider views the front wheel spindle(FWS) when riding.
Every bike I own the FWS is between headtube and handlebars,I do not ride stretched out in fact quite the opposite,I do not have toe overlap,none of my bikes have overly long TT's(longest is 585mm others are 570mm).
The FWS will be viewed wherever it is when the rider is comfortable.
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Ayesha
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Re: Standover measurement

Postby Ayesha » 31 Mar 2013, 2:37pm

reohn2 wrote:
Ayesha wrote: the front wheel spindle should be hidden behind the handlebars....


This has come up before and it's a myth.
It all depends on toptube length and stem length as to where the rider views the front wheel spindle(FWS) when riding.
Every bike I own the FWS is between headtube and handlebars,I do not ride stretched out in fact quite the opposite,I do not have toe overlap,none of my bikes have overly long TT's(longest is 585mm others are 570mm).
The FWS will be viewed wherever it is when the rider is comfortable.


You should read and understand other people's posts before diving in.

"Buy a stem which causes your Lumbar Vertebae to be at 45 degrees.", and then check the front spindle line of sight.

"wherever it is when the rider is comfortable" is usually when the Ischial crests and the Sacrum are positioned so the rider's perineum is flat on a horizontal saddle surface. In most cases this causes the Lumbar vertebrae to rise at 45 degrees.
The bike's reach can be calculated from a selection of upper body dimensions, but I won't go into that. The 'quicky' method which seems to have worked for 100 years is the FWS being hidden.