Author Topic: Seat height - don't assume - check it !!  (Read 4911 times)

Seat height - don't assume - check it !!
« on: March 28, 2008, 10:28:46 pm »
Yesterday one of the riders asked me if I'd been fitted to my TCR.  He was asking because he believe my seat was too low for my leg size.  The junior champion that I had been riding with for a lot of the earlier ride and whom was now in front of us turned and said "Yeah, I thought that too".
We then discussed my seat height and they both thought I should up it an inch !!
This seemed a lot to me and it really made me wonder.
At the next puncture stop I whipped out my Alien and went to undo one of the seat clamp bolts and promptly sheered it off leaving half of it still in the threaded side.  Doh.
I then rode for another 50 miles without it slipping so that was lucky.
When I got home I placed both the TCR and the MonstaThorn side by side and the seat height was the same for both.  As the clamp is broken on the TCR I decided to lift the Thorn seat by an inch for the commute this morning.
As a rule of thumb, my riding partner suggested that whilst sat on the bike and supporting one self next to a wall of immovable object, unclip and place your heel on your pedal and back pedal.  At the down stroke base you should be locking out your knee.
So I did this method and rode in with my new seat height today.
It is too early to tell but I think he was right.
My seat was too low.
It either slipped or I never set it correctly.  I think it has slipped over time.
At work today I was discussing this with one of the road club / TT riders and he reminded me of the 105% rule.  Measure your inside leg and then multiply it by 105% and that is the distance from your seat top to the pedal axle centre.
My inside leg is 90 cm and the distance to pedal is approximately 95cm - so that is about right.
It is funny but I'd thought my thigh muscles were changing shape but I'd put it down to different riding - ie. LSD not TTing to work everyday instead.
Time will tell but the advantage will be greater thigh strength.

Lonewolff

Re: Seat height - don't assume - check it !!
« Reply #1 on: March 28, 2008, 10:36:33 pm »
I always find I need my sadles rather higher than you would at first think - it depends a lot on your pedaling style I think, but a saddle with is even a little too low makes a lot of different to your power output.

Re: Seat height - don't assume - check it !!
« Reply #2 on: March 28, 2008, 10:39:31 pm »
That was exactly his point - power output.
The more I think about it I had noticed that my leg was easier to throw over both bikes ( not like Heather Mills ) lately so my carbon seat posts must slip, gradually.
Apparently you can get a good lubricant from ParkTool that has small granules in it that clasp the clasp once the clamp is tightened.  I shall ask the LBS.

The chap mentioned the different pedalling styles and bearing in mind he had been watching mine for 50 miles so by then he had a good idea that it was too low.

border-rider

Re: Seat height - don't assume - check it !!
« Reply #3 on: March 28, 2008, 11:30:11 pm »
Just take care when you up the miles -  a higher seat may give you more power, but if it's a bit too high it'll hurt after a few hundred k.  But then, a low seat can give you knee trouble...

Rollo

Re: Seat height - don't assume - check it !!
« Reply #4 on: March 28, 2008, 11:51:37 pm »
And once you've worked out what your best saddle height is, it's worth measuring it and remembering it.  Mine is 78cm, BB spindle - saddle top for 170mm cranks.  Once you know this number (remember it's different for different crank lengths) it's a simple matter to check your bike setup and to adjust other bikes to fit.  Saddle-nose to handlebar is another useful number to remember, but there's a bit more leeway here.

Wowbagger

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Re: Seat height - don't assume - check it !!
« Reply #5 on: March 29, 2008, 12:23:52 am »
According to Richard Ballantine the distance from pedal to saddle when the cranks are in line with the seat tube should be 109% of your inside leg measurement.
Oh, Bach without any doubt. Bach every time for me.

Re: Seat height - don't assume - check it !!
« Reply #6 on: March 29, 2008, 12:37:01 am »
I don't get along with the 'heel on the pedal' method. I tried it but it's always felt far too low to me. My saddle is at least an inch higher than that, but then I'm very much a toes down kinda guy.

I don't do huge mileage and no doubt would notice the drawbacks of having it so high if I did, but where I have it at the moment helps stretch out my hamstrings and eases my sciatica a bit.

Re: Seat height - don't assume - check it !!
« Reply #7 on: March 29, 2008, 02:06:11 pm »
I bought a new bike in 1999 (sounds like it was a century ago!) and soon developed knee pain.  This went on for months until I eventually discovered the seat binder bolt was too long and therefor not fully tight allowing the saddle to creep down.

My pedal to saddle top measurement is 868mm max -  higher feels better, but as MV says, on long rides back of leg strain develops if it's any higher.  Know yer numbers, folks.

Re: Seat height - don't assume - check it !!
« Reply #8 on: March 29, 2008, 06:10:04 pm »
It also pays to remeber that over time a saddle will sag by some amount, lowering the effective sadddle height.

I've made (well, that's a bit grand really - codged) a device using threaded rod to really measure saddle height, it amazed me how much saddle height set up by tape measure varied when measured accurately.

Re: Seat height - don't assume - check it !!
« Reply #9 on: March 29, 2008, 06:59:15 pm »
i've found my 531 steel bike does suffer from a little slippage. i really should get round to getting a qr seat clamp, as the nut and bolt currently used are a bugger to undo if i need to raise the seatpost anywhere other than at home. it is only really used for commutes, but having mudguards, it's bound to get used on a flat club run in inclement weather.
she was quite innocent, 'till she got that bicycle - sykurmolanir

Jacomus

  • My favourite gender neutral pronoun is comrade
Re: Seat height - don't assume - check it !!
« Reply #10 on: March 29, 2008, 07:59:22 pm »
I've just checked my measurements - thanks for the thread Grub.

Inseam - in socks to crutch in cycle shorts
Pedal to saddle height - Top of pedal (Time RXS), crank at 6'o'clock, to top of saddle in the centre (fore aft centre)

Inseam: 865mm

Previous pedal2saddle: 890mm

Pedal2saddle @ 105% inseam: 908mm

I'll try this out and report back when I have put a good couple of hours in the saddle.

I guess, as with bike fit in general this is a guide to get one close, from which point fine tuning is expected?
"The most difficult thing is the decision to act, the rest is merely tenacity." Amelia Earhart

Re: Seat height - don't assume - check it !!
« Reply #11 on: March 29, 2008, 08:13:28 pm »
I must be a little strange  ::)

In winter I lower my saddle a little on my touring and commuting bikes for a more relaxed ride. Both my race bikes are setup with higher saddles than the touring / commuting bikes - they're closer to the 'straight leg with the heel on the pedal' setup. My TT bike is set even higher - but then that's beacuse it's ridden on the rivet all the time.

Re: Seat height - don't assume - check it !!
« Reply #12 on: March 29, 2008, 10:35:12 pm »
I've just been out on the Thorn to test the light and the new seat hight felt ace, straight away. 

The funny thing is when I had some photos taken recently by Mrs G to send off I thought that my thighs seemed quite hunched up.  I put it down to the pattern on the leggings and didn't even consider the seat height.

As I broke my seat clamp I have ordered a new gold Hope one - to match the skewers  ;D

Mr blingity bling  ;)

Re: Seat height - don't assume - check it !!
« Reply #13 on: March 30, 2008, 11:50:43 pm »
Grub or shall we now say ....Mr Bling


You flash .... !

I cycle behind someone today and despite telling him in the past he still pedals with his knees pointing outwards (like a frog).

This cannot make it comfortable for him.

Re: Seat height - don't assume - check it !!
« Reply #14 on: March 31, 2008, 06:02:51 am »
Roger and Rae will still remember Catherine on the Dun Run from a few years back.  Her seat was a tad high.  We had to watch her riding for quite some time just to ensure the verdict was correct.  ;D :evil:

urban_biker

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Re: Seat height - don't assume - check it !!
« Reply #15 on: March 31, 2008, 09:46:48 am »
I started getting knee problems on any ride over 100 miles. I'm pretty sure this was due to the saddle being too low. I've since raised the saddle approx an inch and this seems to have improved things although I am getting some rear leg pain/aches which sound a bit similar to what Mal Volio is describing so maybe I went a little too far.

My next few rides are going to be somthing of an experiment as I adjust up and down depending upon the leg pain symptoms that I get ;) The Denmead 300k will be a big test, but I really need to get it right before then if I can.
Owner of a languishing Langster

chillmoister

  • King of Compton
Re: Seat height - don't assume - check it !!
« Reply #16 on: March 31, 2008, 03:12:36 pm »
It's amazing what a small change in saddle height can make ..I had been riding my hack bike for about 3 weeks while the thorn was inthe workshop ...when I got back onthe Thorn the saddle felt too low so stupidly I raised it by less than an inch ...just within 2 days (about 70k) my thighs really hurst and my left ankle was sore.  I then decided to do the 109% measurement and guess what .....the saddle was at the correct height to begin with.  I guess it was the difference in frame geometry between bikes that made me feel the saddle was too low.
appearing in a tea room near you

Re: Seat height - don't assume - check it !!
« Reply #17 on: April 01, 2008, 02:32:58 pm »
My thighs are aching like you would believe.
It is right though.  I am going a little faster and hooking is easier now the saddle is at the correct height.

Glosbiker

  • Gentleman Antiquarian
Re: Seat height - don't assume - check it !!
« Reply #18 on: April 02, 2008, 08:36:34 am »
I needed to raise my saddle on the Pinarello after I realised I'd set it for my right leg which is slightly shorter than my left!

Correct saddle height makes such a difference to your output even if it does feel like you're tottering when stopped at junctions!

I use the heel on pedal measurement which seems to work.  I pedalled for a while on Sunday (my left knee is still pretty unhappy) and with the sun behind me I could see that my hips weren't rocking and my legs just seemed to be moving in one vertical plane.
Question everything, accept nothing.

Biggsy

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Re: Seat height - don't assume - check it !!
« Reply #19 on: April 02, 2008, 09:46:27 am »
It's amazing what a small change in saddle height can make

Agreed.  Even a couple of mm can make the difference between efficiency and inefficiency, and knee/hip/arse ache and no knee/hip/arse ache.

I think I have my saddle slightly lower than what would be ideal for my knees to make my backside more comfortable, but it is only a matter of a few millimeters.
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