wotsit..

[youngoldbloke]

To return to the OP - worth reading the following which answers most of the questions re. bike fit:

http://www.chiropracticperformancecentre.ca/Handouts/Lifestyle/Road Bicycle Fit.pdf

 

[jimboalee]

Shut up, both of you.

I have already described how to measure your Inside leg.

The tailor's method is different to the frame builder's method.

Your "Seated Height" is the distance from the floor to the top of your head when you are seated on the floor with your legs outstretched in front of you. Use a doorway and have a friend mark the measurement.
Your "Standing Height" is self explanatory.
Subtract your Seated Height from your Standing Height and multiply the result by 0.883.

LISTEN TO RANDOCHAP.

This is for Quill pedals and old type shoeplates ( almost an inch from the pedal axle to the socks ), so I use 0.875 for closer Look shoe system.
The measurement you will have calculated will be parallel with the centreline of the seattube and straight up to the top surface of the saddle. In reality, riders will sit forward of the point intersected by the straight line, thus relaxing the riding position.


The 'heel on pedal' method is open to all sorts of inaccuracies like 'sitting on the saddle naturally in a relaxed position'.
It is not worth doing.

The TRUE method is to measure the distance from the floor to the centre of your hip ball on the top of the Femur. This measurement corresponds to the distance from the pedal C/L to the top surface of the saddle with the crank arm parallel with the seat tube in the down position.

 

[youngoldbloke]

Thanks for spelling it out Jimboalee, I am going to check out some of those measurements and try using x0.875 v. x0.883. (BTW I find 'heel on pedal' is useful as a quick and very rough guide when it comes to adjusting an exercise bike in the gym, or a spinning bike. I have just tested Randochaps' 'Indian' method on my [well set up] road bike and it appears to work for me pretty exactly! So that would be a better method for gym use - for me anyway.)

 

[jimboalee]

I find 'heel on pedal' is useful as a quick and very rough guide when it comes to adjusting an exercise bike in the gym, or a spinning bike.

Gym bikes have an adjustment of 1" at a time. Once you have done the measurement work and taken the tape measure to the gym, you note down the notch that suits you most.

Gym bikes also have VERY uncomfortable saddles. I tended to find myself on the nose ( rivet ) to alleviate the pressure on my Ischium.

Most gym bikes have a counter that ceilings at 1 hour..... without padded shorts, most users don't get to the end of the timer...

 

[youngoldbloke]

Agree re. appalling saddles - tend to avoid 'exercise bikes' and use spinning bikes if available. Generally better saddles, also more fore/aft, bar height etc. adjustment, and clips/straps. Prefer the 'fixed' setup too.

 

[Paul_Smith SRCC]

whats that little test you can do for saddle height by sitting on the saddle, putting the pedal in the dead position and the heel of the foot should just touch the pedal? is that right? should it be done with or without cycling shoes on?

ta

There are many different things that contribute to the position that includes saddle height of course, here is the method I use, much of which I have used for over thirty years as a club rider and over twenty working in specialist cycle shops. The points I mentioned below contribute to part of the process, fully respect that others may well use a different way to set up their position.

In response to your question you are looking to have a knee bend ideally around 30 degrees when the crank is inline with the seat tube. Not an easy measurement to make unless you have the correct equipment to measure the angle of course, we would make sure the riders foot is in the neutral position, normally very slightly heel up. A good starting point I have used before I start to measure the knee bend at 30 degrees is as others have mentioned, in stocking feet heel on the pedal at 6 O'clock and leg should be near straight, a bend of the knee will lift heel off the pedal, of course someone who has size 14 feet will then result in a knee bend when cycling very different to someone who has size 8, so this is used just as a starting point.

A lot can effect that 30 degree bend of course, saddle set back for example, with cranks horizontal, foot/ankle in neutral position, if cleats are positioned correctly I drop a plumb from the knee and it just touches pedal axle. Note this can change on different bikes, a low profile time trial or track pursuit rider may look for a position further over the bottom bracket for example.

When I mention "foot/ankle in neutral position" by this I mean the ankling when riding at 60%, or the point when you stop wanting to hold a conversation while riding. Most riders pedaling action and ankling will alter when they trying harder, perhaps a racing effort at speed on the drops, it will differ again when climbing, not only due to the effort but the riders position on the saddle at those times, when climbing a mountain pass it is common to sit back further on the saddle with heel down pedal action for example. If the position is correct the ankling should be in this neutral position at 60% effort, that way the rider can cope with the changes as their style and effort alters.

You also need to make sure your foot is correctly positioned on the pedal, neither to far forward or back. Note where your big and little toe joints are, you can mark the shoe temporarily which helps, the pedal axle centre line should be midway between the two when the foot is on the pedal, this will naturally effect all the above so worth taking note and adjusting if necessary.

If you use clipless pedals also make sure the cleats are correctly positioned, many simply fit the cleat central and let the float allow the foot to move to the natural position, yet this is quite easy to get much more accurate. For forward or backward position use the pedal center line as mentioned above, to angle the cleat sit on a table and dangle legs over the edge, lean forward to replicate riding position and note angle of feet, this is because as you lean forward the angle of most riders feet will alter inwards. You can even allow for how wide your stance is, a petite rider using a triple chain set will have the cleats set towards the outside edge of the shoe where as a larger rider with wider stance may set theirs opposite to that, especially if using a single chain set with narrower Q Factor.

With the introduction of modern shoes, insoles and shims some go even further, you can now allow for Varus/Valgus fore foot.

A Varus forefoot simply means that the fore foot is not flat, but raises slightly towards the big toe, infact the majority of us do not have a flat forefoot; Valgus is the opposite of the above and far less common.

Specialized BG shoes (so not the trainer styles) have varus wedge built into the outer sole to allow for this. BG shoes for me reduced knee twitch towards the top tube at the top of my pedal stroke, with a flat sole I found that it did just that as my foot pushed back down on the sole, effectively as my fore foot was unsupported it collapsed down onto the flat sole as I started to push down over the top of the pedal stroke and my knee would twitch towards the top tube as it did so, with the support of a varus wedge this was all but eliminated, I also used a different insole to allow for the fact that I have standard arches, most shoes, Speciazlied BG included, normally have to come by default with insoles that are set up for flatter arches than I and indeed most of us actually have.

If required you can use shims in other brands of cycling shoes to support a Varus or Valgus forefoot, care is needed to make sure you use the correct type of Shim of course, that must relate to both the type of shoe and forefoot.

There is a quite a simple straight forward way check what type of forefoot you have, all you need is a friend, straight edge and a chair; simply kneel on the chair with feet dangling over the end, making sure knees are level, ask a friend to place a ruler/straight edge accross the forefoot and it is then easy enough to see, after which it is then easy to work out which shim, if any, is required.

Picture shows a Varus Forefoot


It was the combination of both supporting the arch and forefoot that helped me, the changes were only small, under 2mm infact, but 2mm for 60-80 revs a minute over a longer ride adds up. I confess apart from a few knee twinges at the end of a long tour I never really had problems before, although this is something I could do, so I did! As well as helping to reduce the knee twitch I also found that the connection between foot and pedal was more solid and stable and for me it feels more efficient as a result; not so much that it makes a headwind feel like a tail wind that's for sure, but it does feel better than it did.

I repeat, the points I mentioned above are what I use, much of which I have done for long time; fully respect that others may well use a different way to set up their position. Many will no doubt be able to apply a different theory to each of the points I have made and justify why their theory is more suitable, if it works for them that’s fine; by the same token I and many others have also found the method I have described successful.

Worth noting that your position will evolve as you will yourself as a rider

Paul_Smith
www.corridori.co.uk

 

[mickle]

I'm keeping out of this!

 

[youngoldbloke]

To help determine KOPS I use a spirit level to find the point on the top tube vertically above the forward pedal spindle axis, with crank horizontal, and mark this point using a piece of insulating tape, or small sticky 'dot'. This gives a point to refer to when riding, and in photographs. Also possible to involve a helper with a digital camera to measure knee bend angle. Lines can be drawn on photographs and the angle measured.

(edit: The article I linked to above 'Road Bicycle Fit' covers most of the points referred to by Paul Smith and indicates that an angle of between 25 and 30 degrees is desirable)

 

[summerdays]

Incedentally, here's another interesting way to find a ballpark saddle height:

Put your arm over the bike, with the apex of the saddle in your armpit. Reach down to the BB and extend your fingers. The tip of your middle finger should reach the spindle centre. It's amazing how close this will come to most to other technical measurements. I hear Indian bike rental guys use this method!

Hmm I thought I would try this one out - knowing I have long arms - and I can confirm that it got it wrong for me by about an inch or so.

And its not that my saddle is too low either as Mickle adjusted that the last time I saw him (though I put it up about a mm or two afterwards - I think my position riding the bike is different to my stationary position or that I just prefer a slightly more stretched leg). If anything I have a tendancy to have it too high I think.

Its obviously very complicated by the number of factors you need to take into account. In my case I know that one leg is fractionally longer than the other - thats the knee that tends to move towards the top tube near the top or the pedaling circle. I also have hyper-mobile joints (think thats the correct term). At some stage I'm going to pay for a proper bike fit but probably when contemplating the next bike.

 

[punkypossum]

Mine is set to leg straight when heel on pedal at 5 o'clock position (which is what it comes up with when I do the leg length x 0.8whatever. This is how it works best for me (I tend to ride with my toes pointing down a bit anyway...).

 

[Randochap]

Its obviously very complicated by the number of factors you need to take into account. In my case I know that one leg is fractionally longer than the other - thats the knee that tends to move towards the top tube near the top or the pedaling circle. I also have hyper-mobile joints (think thats the correct term). At some stage I'm going to pay for a proper bike fit but probably when contemplating the next bike.

Yes. That's why a final "exact" fit can only be ascertained by the rider, as soon as that rider has gained enough knowledge.

A good fitter (and I'd recommend seeing a knowledgeable physio -- preferably with a sports med degree) will sort out your leg length issue ... by shimming cleats. The majority of riders need their cleats shimmed to deal with (mostly) varus and (occasionally) valgus issues, as per Paul's excellent post.

I use Specialized shoes, which helped with my varus positioning, but still require 2 cleat shims on the left and 3 on the right. Speedplay pedals have allowed my natural heel-in on the right to return, minimizing the knee issues I once suffered.

Bike fitting is a complicated affair. Once you start putting in the hard miles, it becomes critical to pain-free cycling.

 

[jimboalee]

Reading between Randochap's lines, he is saying "You will never get it spot on first time", which I agree with.

Visiting a 'Fitting clinic' et al, will be a waste of money, because all the relavent info is on the web and a decent LBS will give advice.

The info that is NOT on the web is the Framebuilder's own secrets.


A 28 year old pro cyclist will have been competing for at least 15 years. Over that time he/she will have grown, and his/her club coach ( and later frame supplier ) will have been adjusting the bike's fit to suit his/her dimensions.
Pros ride at least 100km every day, it is their job. They tweak regularly, but only by a couple of mm at a time. Muscles grow; Bones grow and if a rider has a bad fall, the leg that hits the tarmac will heal to different dimensions than before the fall.

I was a pro skateboarder in the seventies, and the hip which kept hitting the bottom of the pool is considerably more structured than the other hip. When I got fitted for a bike frame in the eighties, my framebuilder noticed this immediately as I stood there in my lycra shorts.

My legs are unequal, but this doesn't stop me riding 300km Audax on an 'Off the peg' Dawes Giro. It is set-up to my framebuilder's secrets and I have no problems. ( The law of Sod is being beckoned ).

Also, when a novice cyclist is adjusting, the bike will feel different after a couple of hours of riding, so after a tweak, go for a 50km circlular and feel how it is. To get your 'perfection' might take weeks. Then, as I have said, your muscles have improved and the bike might need tweaking again.

The 0.883 ( 0.875 ) rule gets close, and then a maximum 2mm at a time tweak thereafter.

 

[roadiewill]

OK Ive tried the heel straight a 6'0clock thing, but I feel its a little vague and have tried the inseam x 0.883 method.

This is weird now because the result I get for the inseam method is a saddleheight of 75cm, yet my current setup through using the heel method is a good 4cm higher???? odd?

am I measuring the centre of the BB to saddle top right? What I do is run the measuring tape in line with the seatube, in other words, it is not vertical. should I be measuring the height vertically from two straight points?

this is how Im doing it atm:

 

[Randochap]

Yes, measure from centre BB to saddle top. If you feel there is some major discrepancy, my guess is your body measurement is off.

 

[roadiewill]

what do you mean by body measurement being off?