bike positioning help please

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samsbike
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Re: bike positioning help please

Postby samsbike » 29 May 2013, 5:04pm

Well I have had an interesting weekend.

I decided to make my mtb some sort of fast road hybird, but getting it fitted was an issue as I based it upon what the road bike was.

So I followed Colin's advice and just set it to what felt right.

The seat moved forward by almost 3cm (there is a 0.5 difference between the road bike and mtb 73.5 v 73) and I adjusted the seat height. Oddly I could not understand why the seat was much lower on the mtb, but realised today that the BB on the mtb is higher. When measured I have more or less come to the same height. This is reassuring for me, proving to me that I can sort myself out to an extent.

The reach feels much better on the mtb. I finally managed to track down the geometry for my mtb and apparently the virtual tt is 590mm. I have no idea on how they measure that as I cannot get to it using a measuring tape. The stem is 100cm so overall 690mm but the bars are about 2cm higher on the mtb.

The road bikes reach is about 558mm (tt) + 100mm stem + about 55mm to the hoods = 713mm, so slightly more, but I think I feel a big cramped.

I think this has more to do with the fact that the bars are a bit lower. I think next I am going to try a steerer extender but not sure it will work on a carbon fork with a steel steerer.

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531colin
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Re: bike positioning help please

Postby 531colin » 29 May 2013, 5:38pm

Its probably an alloy steerer in a carbon fork. I think you should be OK with an extender like this

Image

inserted well down into the steerer....ie down past the headset, so the steerer is re-enforced throughout its length.....by the head tube at the bottom, and the extender at the top.

I wouldn't extend a carbon steerer.

samsbike
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Re: bike positioning help please

Postby samsbike » 29 May 2013, 5:46pm

colin does that mean I have to take out the star fangled nut?

sam

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531colin
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Re: bike positioning help please

Postby 531colin » 29 May 2013, 5:50pm

Yes.
I do it from below with a long steel rod cut at an angle so I can go round and tap the "teeth" of the star nut upwards.....its a bit less brutal than just walloping it! :shock:

niggle
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Re: bike positioning help please

Postby niggle » 29 May 2013, 10:28pm

531colin wrote:Its probably an alloy steerer in a carbon fork. I think you should be OK with an extender like this

Image

inserted well down into the steerer....ie down past the headset, so the steerer is re-enforced throughout its length.....by the head tube at the bottom, and the extender at the top.

I wouldn't extend a carbon steerer.

So is that type of extender preferable to this type:

Image

http://www.wiggle.co.uk/bbb-bhp-22-stee ... -extender/

due to the former extending down into the steerer?

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531colin
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Re: bike positioning help please

Postby 531colin » 29 May 2013, 11:38pm

I prefer the "quill type" extender because if you can insert it a good way into the steerer, then it re-enforces the unsupported bit of the steerer above the headset, and it must be straight relative to the steerer. I once had an external type extender which didn't sit completely straight, and the headset was impossible to adjust critically. With the external type, the stem must fit completely above the collar, but the internal type provides stepless adjustment.

I always forget to add........"you will need extra headset spacer(s)"

samsbike
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Re: bike positioning help please

Postby samsbike » 30 May 2013, 8:41am

Being thick but there are 2 sizes - 25.4 - 22.2 or 28.6 -25.4, and I use I think a 1 1/8 in steerer.

thanks

Brucey
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Re: bike positioning help please

Postby Brucey » 30 May 2013, 8:45am

if you have a 1-1/8" steel steerer, the 25.4/28.6 one is the one that should fit OK. Best to check your steerer ID before purchase.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

samsbike
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Re: bike positioning help please

Postby samsbike » 30 May 2013, 9:56am

Brucey wrote:if you have a 1-1/8" steel steerer, the 25.4/28.6 one is the one that should fit OK. Best to check your steerer ID before purchase.

cheers


What is a steerer id?

Thanks

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531colin
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Re: bike positioning help please

Postby 531colin » 30 May 2013, 10:48am

internal diameter

Vladimir
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Re: bike positioning help please

Postby Vladimir » 5 Mar 2014, 5:53pm

Sorry to resurrect this thread, but it seemed the best one to me.

I hear what Colin says about cyclists not straightening the knee and hence not recruiting vastus medialis which leads to pain in the lateral aspect of the patellar groove and that's all good.

NOW - what does pain in the tendons under the patella indicate?

Answers on a postcard please

Thanks

Vlad

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531colin
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Re: bike positioning help please

Postby 531colin » 5 Mar 2014, 10:59pm


samsbike
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Re: bike positioning help please

Postby samsbike » 1 Mar 2015, 3:56pm

Again a rather late update.

I have been trying the steve hogg balance test and proved to myself that I need to do things to learn rather than just read, sigh.

Anyway, I had been working on a setback of 8-9cm (depending on saddle) and still got shoulder pain, but I managed to do his quoted balance test (although I could only do it on the road into a headwind for around 2 mins). What I did not realise that having too much setback means that your body will balance, but what it will be difficult is to ride no hands, as the weight is too far to the back.

So I went back to the drawing board and back onto KOPS (well as much as I can being stationary in the shed). This has brought the saddle forward to around 7cm behind the BB. With regard to it working I dont know but I can ride no hands, and just about ride with one finger (around the block).

Am commuting on Tuesday so will see how well its worked.

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531colin
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Re: bike positioning help please

Postby 531colin » 6 Apr 2015, 10:45am

Adding a link to a bit about saddle height....http://forum.ctc.org.uk/viewtopic.php?f=5&t=92633&p=884665#p884665

samsbike
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Re: bike positioning help please

Postby samsbike » 8 Apr 2015, 4:41pm

Driving myself crazy trying to figure out what was causing my aches and pains I got a bikefit done.

The result was a seat height of 77cm which is pretty much was I found out 3 years ago but kept putting the seat down because I think my pelvis was moving and I also kept making changes trying to understand why my pedalling bit wasn't quite spot on.

Seatback is 8cm, which again was where I was years ago instead of the 9cm I thought it was.

I was also ok with my reach, although my bars dropped another 1cm, which felt more comfortable.

However the cleats were adjusted and the issues I am having are not to do with my bike but other issues from old accidents.

All in all, a good experience as it gave me feedback to what works and doesn't work.

Was it worth it, for piece of mind yes as I had lost confidence in my ability to make the right choices.