Seatpost Adjustments

[MacB]

Hi, on the scrounge for info again, having been changing saddles, setting up new bike etc. On both bikes I have alloy posts with set back and the tilet adjustment is via the saddle fixing bracker sliding/tilting in position. I've been trying to adjust these to give the correct position and angle, IT'S A NIGHTMARE. Process I'm following is, straight metal pole from centre of BB running vertically(is an old curtain pole), then using a spirit level on the side. When vertical I measure from pole to nose of saddle. For both bikes I'm struggling to get the saddle nose close enough to the BB and the saddle level.

So I'm thinking of new seatposts with less, or zero, layback and tilt adjustment seperate, maybe something like the Thompson Elite straight version.

Anybody got any tips, recommendations for posts, or info on something I'm doing wrong?...thanks....Al

 

[dodgy]

I'm not a great believer in using spirit levels, tape measures, set squares, plumb lines etc etc etc to get a good fit. I adjust to get it almost right then make tiny adjustments every 10 miles or so until it feels perfect. If it feels right, it probably is - regardless of what the perfect forumula says!

 

[MacB]

thanks Dodgy, I'd agree and am happy to make small tweaks as I ride. The measuring/spirit level bit is just to get as close as poss to begin with. My problem lies around 2 areas:-

1. due to layback the saddles look like they're going to end up so far forward I can't clip on my saddle pack behind.

2. the tilt adjustment, on my current posts, seems very limited and clumsy. As they have just one allen bolt to cover all adjustments, I seem to get one bit right and tighten, only to find the other aspect's now wrong.

I'm seeing posts online with zero setback and 2 screw micro adjust aspects, allowing precise angle tuning. Based on the above this would seem to fit the bill, just wanted to verify that with those more knowledgeable...cheers....Al

 

[MacB]

Right, taken some measurements based around, setabck and layback, as I understand them, so:-

setback = distance from nose of saddle to centre on BB, mine is currently about 90mm on each bike if I allow for saddle pack to fit. I believe I want about 60mm.

Layback = offset at top of seatpost, so measuring from centre on seatpost to centre of bracket/bolt - so my 2 seatposts are 30mm and 35mm layback. Coincidentally about the amount that I feel the saddle nose needs to come forward. This would indicate that zero offset posts would solve my problem. But this means more spend.

Is there any reason, in the short term, that I can't rotate the seatposts so that the Layback is facing forward. Then move the saddles back a bit to accomodate this?

 

[phil_hg_uk]

When I set up my Brooks B17 it took ages first I used the plumb line method (set pedal at extreme forward postion then drop a plumb line from the point of of the bone that protrudes just below the kneecap, it should go through the ball of your foot bisecting the spindle of the pedal) to get the saddle fowards/backwards postion correct then adjusted it as I rode stopping every few miles to make micro adjustments.

As you say the tilt is difficult as with my seat post it has a single allen bolt to adjust the front/back and tilt but it is possible. It took quite a while to get the tilt as I like it infact I reckon it is about right now so it has taken me about 2 months to adjust it.

The height took some playing around with I have the saddle way higher now than I used to and again it was just trial and error adjusting it as I rode.

I still find now that sometimes I will stop and make a minor adjustment here and there.

 

[MacB]

ok, you can't twiddle it round the other way, obvious when you try it

Thanks Phil, looks like I'm going to go the zero offset route route as that should get the saddle nearer centre rails, so more to play with either side. I'm also getting the mocro adjust bit as the combi, one bolt, bit is really doing my head in.

I'll report back when done, or I have gone insane

 

[MacB]

well, bought a cheapo in-line/zero offset, and micro-adjustable, post from Halfords and fit to the new bike. Results:-

I got the right size!!!

after sodding around with the one bolt tilty bit today the micro adjust was a revelation, got saddle level in about 30 seconds.

due to layback/offset I've been using 130mm stems to get the reach, now have to look at reach again, will test ride a bit first. On both bikes the spacers are all below the stem and the stems rise at quite an angle(both adjustable ones). So to extend reach I can move spacers, reduce stem angle or use a shorter stem. They are butterfly bars so I angle them as well. So many choices!!! Made my own plumb bob from string and a heavy bit of metal, made life easier as well.

Off to read up on bike fitting stuff to see relative impacts of the various changes

 

[phil_hg_uk]

The book I used and got the plumb bob tip out of is this one --> http://www.amazon.co.uk/Essential-Touring-Cyclist-Complete-McGraw-Hill/dp/0071360190 you might want to take a look.

There is also a preview of the book here --> http://books.google.co.uk/books?id=...gt21Aw&sa=X&oi=book_result&ct=result&resnum=4

It is very tricky getting a bike exactly right I am still finding on my Ultra Galaxy that when I ride on the hoods my arms get sore, I think I will need to invest in shorter stem to get the bars nearer.

Oh well all part of the fun and once I get it right I will probably buy another bike so I can start all over again

 

[MacB]

thanks Phil, head now spinning from following the links on this page:-

http://www.cyclemetrics.com/Pages/FitLinks/bike_fit_links.htm

so many takes on it, KOPS(knee over pedal spindle), is the way to go and it's also a myth. Saddle should be nose down, horizontal, nose up. Nose of saddle to centre BB should be, X, Y or Z, depends on which take on KOPs you follow. Rivendell bikes like the bars to be higher than the saddle. A few say that you should be able to take your hands off bars and not fall forward. It's all good in the sense that I understand the terminology and the claims around the impacts of various positions and what effects changing them have.

Now that I know all that it's down to trial and error. Best thing I've found today is that micro adjust seatposts are far easier than any other method I've tried. It's also verified for me that I really need to work forward from saddle.

I suppose I could have just gone and paid for one of these fancy fitting sessions. But I'd still have tried/wanted to tinker afterwards anyway, so might as well learn to do it now.

 

[Aperitif]

You need to lie down in a dark room MacB
Pleased you are making progress - reading with interest.

 

[MacB]

well, managed to get another inline seatpost today so both bikes now equipped. Still need to tinker with reach a little, but will do that slowly. So took new bike out for 20 miles and going along quite happily. Then started to get some pain in right knee, felt like I was quite low. Next, my right leg starts brushing the crossbar. Memo to self, after fettling make sure all bits are done up properly, the seatpost was lowering and twisting

Microadjust still my friend, got second saddle level in no time. Now I'll just carry the allen keys and tweak a little at a time, measuring as I go along.

 

[phil_hg_uk]

Which seatpost did you end up getting ?

 

[MacB]

just the bog standard cheapo, 400mm, microadjustable, inline, ones from Halfords, labelled bikehut I believe. They would appear to be of similar standard to the setback ones I had. When I've got this all sorted, and have lost enough weight, I may look at a carbon one for the weekend bike.

Now done 2 full commutes on the new bike and have been tinkering some more. Found I prefer the saddle with the nose tilted up very slightly, maybe 5mm. Have moved it back slightly as well, about 10mm. Think I may have to raise a bit, going to wait until I'm in ride company Friday night. Then I'll double check my position via a decently trained eye.

 

[montage]

off topic but.... chance of updating the pics of your projects on the photos threads? These are interesting projects and I am intrigued and wanting to be inspired!

 

[MacB]

sorry Montage nothing to update yet, still got to send off for powder coating, had to settle bill for new Surly last week. Anyone that thinks building up is cheaper, has better sources than me Will put update in the thread.