Thorn sizing

[ourclarioncall]

I see Thorn will build you a bike set up to your preferred posture - relaxed or sporty etc etc

Does this measurement take into account your saddle height ? Is it assumed that you set your saddle to the recommended height put out over the internet for best efficiency etc. I mean where your leg is almost straight. I have experimented with putting my seat up really high and I was very surprised at the difference , I could blast up hills with ease being able to generate much more power through the pedals. But In the end I dropped the height to where it was a bit more comfortable and not chaffing or painful. But I would recommend people try it at least once , you may be really surprised. But if a tangent I went on there but yeah,

Just wondering if saddle height is an important factor to how Thorn would set up a new bike for you

[leftpoole]

The bike builder asks what height from the ground you want the saddle, also the bars.

[PH]

Hopefully any saddle measurement will be taken from the bottom bracket rather than the ground.

[leftpoole]

Hopefully any saddle measurement will be taken from the bottom bracket rather than the ground.

As possibly many (?) already know, I build my own rather nice bikes.
One time I actually purchased a new built for me Audax . The builder called and asked for height from ground to top of saddle and same for bars. The bike duly arrived set to my measurements exactly!
I do agree however that the measurement from centre of bottom bracket to be most accurate. This is how I do it so it must be correct 
John

[ourclarioncall]

Okay , so your finished bike can be shaped to your preferred settings

What if you are just buying a frame that’s suitable for your height according to their charts? And building the bike up yourself

Is the frame size less important because posture such as relaxed or sporty can be created via the height you place the handlebars and also the length and angle at which the bar sticks out

[JohnR]

Is the frame size less important because posture such as relaxed or sporty can be created via the height you place the handlebars and also the length and angle at which the bar sticks out

There's a limit to how much you can compensate for having the wrong frame size. A different (length / angle) ahead stem can move the handlebars back / forwards / up / down by a few centimetres and you can also move the saddle back / forwards on its rails with some potential for further adjustment using another seatpost with a different setback. However, there are limits to such adjustments before other problems surface. For example, I knew that the frame on my previous bike was smaller than optimum and while I got the saddle-handlebar spacing OK, one unwanted problem was that the front mudguard sometimes clashed with my toes and my heels occasionally hit the chainstays where the widen. Another issue is making sure that whoever builds the bike doesn't cut the steerer down too far. Adjusting saddle height is usually easy unless you've got abnormally long or short legs.

I've decided that the best way to figure out the optimum geometry is to ride the current bike for a couple of hours, decide if the hands - feet - saddle triangle feels OK (and if not, why not), then relate those measurements to the proposed frame and try to land in the middle of the range of adjustments. There's plenty more food for thought about bike fit at https://www.sheldonbrown.com/kops.html . There's also the possibility of thinking you have the optimum set-up and only discovering there's something better by trying it.

[ourclarioncall]

Yeah it seems to be a real fine art getting a position and frame etc that works for you.

I’ve risen on 18, 20 and 22 inch bikes in the last couple years and it was interesting.

Had a bit of trouble with saddle sores which was frustrating and hard to figure out the problem

Think it was a mixture of (sorry for being graphic) the type of underwear I was wearing (under waterproof gotetex cycling trousers) , sweating , chaffing , the saddle being a little too wide which seemed to be a source of rubbing , and possibly being a bit overweight with too much body fat.

I got a brooks saddle and that’s has helped . Changed the type of underwear which helped, and also the experimenting with seat height seemed to promote less or no chaffing .

I’m getting tired of the mountain bike style posture tho and really want a more upright position for more comfort hence why il attracted to Thorn touring bikes with higher bars

[PH]

It's not a simple subject.  It can be broken down into two elements, bike geometry which determines the handling, and bike fitting which determines comfort.  People get them mixed up, and/or don't realise the interaction, for example a too small bike can be set up for a comfortable position, but the weight distribution is then wrong for the handling...
Thorn have a good reputation for getting it right, by asking the right questions and based on their experience.  What they can't do is set the rider up perfectly, because we're all different.  If you're lucky, your perfect covers a range of fit, unlucky and it'll need to by mm perfect.
Here's some interesting pointers, it takes a bit of working through, but I don't know anyone who having done so hasn't benefitted from it, including me.
https://wheel-easy.org.uk/wp-content/uploads/bike-set-up-2017a.pdf

[leftpoole]

In my opinion at age 70!
Thorn staff generally advise smaller frame size. I have always been told size smaller.
I have made my OWN mind up based on my height ride health and lack of wealth. My size has always been one size larger.
John

[ourclarioncall]

Thanks guys

I got my daughter to film me tonight on 2 different bikes , an 18” and a 20” frame ,’so I go stand and sit and see how things look.

i tried to post pics on here but think the file sizes were way too high. Never mind.

Anyway, the bottom line is I found  the 18” with a very high saddle height as recommended online with the leg almost straight to be the most comfortable

I find this kind of annoying as I like the look of larger frames ! And really want to get the largest or second largest frame size . All very unreasonable and vain I know. I’m not sure if I want a bike to ride or I want it as a piece of art 😁

I do feel a little cramped on the 18” like I could use a little more space. But with the 18” frame I feel a bit more in control , as in if I was going fast round a corner and want to pull the brake and do a skid like I used to when I was 10 years old I would feel more connected with the bike and the ground , more in tune and more confident.

On the 20” I found myself pushing back off my hands on to my fingers to get into a more relaxed position.

The 18” and 20” are both the same model bike, a Carrera hybrid bike from Halfords

Before this I used to ride a 22” cape wrath Claud butler mountain bike. I felt it was a touch too big or long and think I used to do the same thing, pushing off my palms onto my fingers to get into a more comfortable position.

I measured my stand over height and it was in the longer leg catergory which gave me hope I could use the largest frame possible.

This info is probably not very helpful without pictures or actual measurements but I throw it out there anyway .

I’m just over 6 foot tall. Not quite 6’ 1”

[JohnR]

Thorn staff generally advise smaller frame size. I have always been told size smaller.

My ex-demo Mercury was listed as "This bike suits someone of roughly 5ft 5- 5ft 8". I'm 5ft 7 so I reckoned it would fit and went on a 43 mile ride on the day after receiving the bike so I could decide what needed adjusting. I hadn't planned to go that far but the bike (with one of my saddles) was comfortable. This suggests that Thorn's estimate of the sizing was good. Fine-tuning involved fitting a shorter ahead stem orientated to raise the bars a little but this shorter stem was also related to fitting Ergotec AHS handlebars with two main hand positions.

[ourclarioncall]

I hear thorn get a good rep for sizing correctly. Stubborn guys like me that care about asthetics too much might throw their advice over the shoulder haha but yeah, I think it be wise to listen to what they recommend bearing in  mind there are always occasional exceptions to the rule