Head tube v reach measurement.

kingrollo

My current bike has a 145 head tube - after a whole series of hip/hamstring problems - I took it for bike fit, who flipped the stem and made one or two other adjustments - comfort wise I have been fine since. Its now coming up to new bike time - a couple of bikes I like - Dolan Dr1, de rosa idol - come with a 135 head tube - although they both describe themselves as sportive bikes - and actual reach measure is only around 8mm more than my current bike.

Hope this doesn't sound like a daft question - but does the smaller head tube place me in a significantly lower position - my initial thoughts are that would - but then looking at the figures for reach I am not so sure...

me-109

Simple maths suggest you just need an extra 10mm of spacer than you currently have in order to achieve the same stem height. The extra reach on the frame could be compensated for with a 10mm shorter stem and/or bar selection.

kajjal

It varies depending on the individual and how accurate your bike fit is. If your bike fit is spot on then minor adjustments are unlikely to be noticed, if your bike is at the limit to the reach you would find comfortable and you increase it a bit more you could get issues. It’s a bit subjective.

If you search the net for a stem calculator you can experiment with different stem sizes to see the affect they have for position of the bars. As an example my mountain bike bars were too high and too far away. Worked out where I wanted them and played with the stem Calculator to work out which replacement stem I needed. Went from 90mm 6 degree in upright position to 70mm 6 degree in downward position.

sloppyschleckonds

kingrollo wrote:

My current bike has a 145 head tube - Its now coming up to new bike time - a couple of bikes I like - Dolan Dr1, de rosa idol - come with a 135 top tube -

I wouldn't be comparing bike Head Tube lengths with Top Tube lengths

jessand

I think you should be looking at stack height rather than reach figures.

kingrollo

Current bike
stack 545
reach 377

Dolan Dr1
Stack 534
reach 382.4

So I will be lower - but how low is that ? - many years ago I had a pinarello which put me in in a very crouched position - I wouldn't want to go back to that

imposter2.0

Spacers come in varying different sizes - as do stems.

kingrollo

Imposter wrote:

Spacers come in varying different sizes - as do stems.

Yes but I don't want to spend £2k+ on a bike and then bodge it so it fits - if the measurements of the dolan require that.

timothyw

If you already have a flipped (pointed upwards) stem then you ought be looking at the size up and perhaps a shortened stem.

At the end of the day, stack and reach measurements and a stem calculator (google it) are your friends.

Handlebars are also a factor though, at the most extreme end, you could put these bars on your new bike and it would give you 15mm of extra height - https://www.specializedconceptstore.co. ... 15mm-rise/

imposter2.0

kingrollo wrote:

Imposter wrote:

Spacers come in varying different sizes - as do stems.

Yes but I don't want to spend £2k+ on a bike and then bodge it so it fits - if the measurements of the dolan require that.

Different size spacers and stems are not a 'bodge' ffs, they are there to help you get an optimum fit on whatever bike you have. The chances of any bike being a perfect fit out of the box are slim to non-existent.

mfin

OP.

How many spacers (total mm) under the stem do you have on the existing bike, how tall in mm is the headset conical spacer, and what length stem are you running? I assume this stem is flipped upwards yes?

From that it will be easy to work out, on face value the new bike will need another 10mm spacer over what you already are running, even more if the headset conical spacer on the new bike is not as tall as the one on your existing.

If you are already running a big load of spacers, the Dolan is not going to work.

Try providing the information above then it will be easy to work out.

kingrollo

ok - here is my current set bar\stem setup

mfin

I'd probably duff the Dolan off then as an idea (even without seeing it's headset conical spacer height) from looking at that photo and the provided reach and stack figures.

That stem is already short. Imagine that picture was the Dolan, if so you would likely have the spacer that's above the stem put below it, but the stem might be 10mm shorter and still flipped. Flipped stems are a sign of a badly picked bike in most cases.

Find a bike that fits you better not worse. You should be looking for something with a bit less reach (or same at minimum) and about 20mm or even 30mm more stack (if such a bike exists). So the Dolan is heading in completely the wrong direction.

Bear in mind many bikes that might interest people are not even close to ideal in any of the available sizes and should as such be dismissed immediately.

letap73

Mfin's advice is spot on. Sadly the Derosa idol also appears out on the same basis as Mfin's post.
The following are more in line in terms of geometry:

Canyon Endurace:
Small - Stack 556 Reach 373
Synapse (Carbon):
51 - Stack 549 Reach 370
Defy:
Small - Stack 546 Reach 373

Others with smilar geometries - Specialised Roubaix, Trek Domane, etc. Virtually every major bike manufacturer makes a bike with a high/stack ratio.
Obviously it will come down to personal preference.

Camcycle1974

He could try flipping the stem and lowering the bars and riding the bike for a month to see what adaptations the body may make to the new position. This would then determine if the lower stack, longer reach Dolan would work or not. Having high bars does not always = comfort IME. Have recently gone from a stack/reach ratio of 1.5 to 1.44 with no comfort issues. Short reach bars with extended drops could be an option too, similar to the bars supplied on the Giant TCR. I'm lower on my TCR but the reach is not as long as my Enigma due to the bar shape. Some flexibility and core stability exercises wouldn't hurt either.

mfin

letap73 wrote:

Others with smilar geometries - Specialised Roubaix, Trek Domane, etc. Virtually every major bike manufacturer makes a bike with a high/stack ratio.
Obviously it will come down to personal preference.

Yep, I spent 60 seconds looking and see an Endurace CF with 378 reach and 571 stack.

kingrollo

Thanks for all the responses

I do have a couple of other bikes in mind from Kuota and Bianchi - these have the taller head tubes. The dolan just caught my eye and came in quite a bit cheaper and you can pick and mix on the spec - The 135 head tube was always a red flag though - I just wondered if the other angles of things etc would mean that it wasn't actually lower (wrong on that one)

The other more difficult question is would riding 10mm lower be problem - I asked my fitter to get me in an upright position as I was having (at the time undiagnosed) hip pain - much later that turned out not to be bike related. Amongst other thinks I now do yoga and have no problems since. The slightly lower position therefore may not be a problem - but @ £2k I doubt I will be taking the chance.

I can save a load by buying on the works salary sacrifice scheme - but it (mostly) has to be a shop purchase - so that would rule out canyon for example.

Thanks for the help though guys

Camcycle1974

kingrollo wrote:

Thanks for all the responses

I do have a couple of other bikes in mind from Kuota and Bianchi - these have the taller head tubes. The dolan just caught my eye and came in quite a bit cheaper and you can pick and mix on the spec - The 135 head tube was always a red flag though - I just wondered if the other angles of things etc would mean that it wasn't actually lower (wrong on that one)

The other more difficult question is would riding 10mm lower be problem - I asked my fitter to get me in an upright position as I was having (at the time undiagnosed) hip pain - much later that turned out not to be bike related. Amongst other thinks I now do yoga and have no problems since. The slightly lower position therefore may not be a problem - but @ £2k I doubt I will be taking the chance.

I can save a load by buying on the works salary sacrifice scheme - but it (mostly) has to be a shop purchase - so that would rule out canyon for example.

Thanks for the help though guys

10mm shouldn't make that much difference. Your body will adapt. If you are fairly flexible then you can probably go lower. I'm 44 and ride a TCR with no issues and I'm no super lightweight racer. Drop out a spacer and give it a go. You can always put it back but give it a fair go first.

mfin

Camcycle1974 wrote:

Drop out a spacer and give it a go. You can always put it back but give it a fair go first.

This. Try it for a month or so before buying, one test ride won't conclude much. While you're at it flip the stem back over as you don't want flipped stems.

Maybe you need a bike fit if you're not sure what your best fit is. Some people can work it out themselves, others struggle. We can't tell what will fit you over the internet. All we can help with is transferring an existing fit onto another bike.

If you don't sort out what fit you want, picking a size of a new potential bike is a bit of a lottery.

kingrollo

Any time I buy a bike - I bite the bullet and pay around £100 for a bike fit with the same fitter I always use. I have asked him about pre bike fit or a consultation discussing various options as we have on here - not quite sure why but he doesn't seem keen to do this.

I guess there is always going to be a leap of faith to some degree

mfin

You shouldn't need a bike fit every time you buy a bike.

Once you know you are completely right setup on a bike it is easy to transfer that onto another bike, getting another bike fit each time is a complete waste of money.

So, either...

1/ You are happy with the fit on the existing bike and want that fit to be the same on the new bike
2/ You are not sure if you are happy with the fit on the existing bike

Even if the answer is 2, you can take THAT bike for a bike fit, confirm it's right by riding it a good while, then all you have to do is transfer that onto a new bike. That purchasing then involves choosing a suitable bike that the fit will transfer across to well (without a daft amount of spacers or excessively long or short stem and no need to flip it.

So, if we were to assume your current bike fits bang on configured how it is, the conclusions made up thread stand. If not, make it fit and check it's right then you can move forward logically, transferring that fit.

Note here that you might think that people should be able to go get fit while purchasing (such as 1st time riders), but most people on here know that if you go for 5 bike fits, you'll come out in 5 different varying positions, so nothing will ever be as good as getting a fit then riding and finding out whether it is "goldilocks" or whether you need to tweak it.

nusnus

You can do a DIY fit relatively cheaply. Put your old bike on a mag trainer and take a video of yourself spinning. Even better go to the lbs and ask them to put the bike you want on a trainer and shoot the video there. Then use this niffy app to measure your angles at various stages of your spinning dynamics: https://www.obstri.com/fit/. There are plenty of resources online that describes the upper/lower bounds of various join angles, like this one: http://bikedynamics.co.uk/fit02.htm.