Longer seatpost + smaller frame

[piyush kaul]

Hi

is using a slightly smaller frame plus a longer seatpost a good option?
what is the other way round...buying a larger frame size bike?

[deepakvrao]

I would say right size frame should be best ;-)

[Chethu Gowda]

I have seen decathlon guys suggesting to go for a size where the seat post is elivated around 5 inches and the rider is able to touch ground with both toes sitting on teh saddle. even i was made to choose RR5.2 of medium size by decathlon guy (im ~5.7) though I could easily ride large frame with the saddle almost touching it's base.

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[piyush kaul]

same here i chose a 18 inch frame rather than a 21 inch bcoz it was big for my height. now i feel that the frame is a little small for my size(5 feet 10 inches). i wanted to see if it is possible to use a longer seatpost with the existing bicycle i have or should i buy a new one with a larger frame size say 19.5 inches.

On Thursday, November 22, 2012 12:41:36 PM UTC+5:30, piyush kaul wrote:

[Karthik Vijayakumar]

I am no expert on bicycle framing, but I believe if the saddle is nearly at its base, then most probably your arms would pretty much stretched out, which is not a good thing, its very easy to develop shoulder pain like that.

-Karthik

On Thu, Nov 22, 2012 at 12:41 PM, piyush kaul <piyushk...@gmail.com> wrote:

[Yateesh Kumar]

Hi Piyush,

Check this link www.ebicycles.com and check for your ideal frame size. In my opinion, 18" frame is just right for you.

Regds
Yateesh

> what is the ot...

[Uday]

This is a good example of one of our very own Bangalore cyclist, Shreeju having a problem because of a smaller sized bike. 

Be cautious. If you get a little overboard, you'll encounter problems that you might not have overseen at all!

http://ipedalthereforeiam.blogspot.in/2012/01/story-of-my-new-bike.html

+Uday

[Uday]

Let me correct myself: 

 If you get a little overboard, you'll encounter problems that you might not have foreseen at all!

[Georg Leuzinger]

frame design is so that saddle should never be at bottom of seatpost just above the top tube. generally 5-7" saddle post is normal.

also i would say from my experience a smaller frame is better than a too big one. it is cautioulsy right that salesperson recommends the medium size when the large one is onlyjust a bit too big!

regards,Georg

[George Joseph]

Between a larger or smaller than ideal - go for smaller. You can
handle a smaller frame easier and it'll be slightly lighter and the
frame will be stiffer.


George Joseph
gjos...@gmail.com
IN cell: 91 94-83-501169
NA cell:1-847-859-9591

[piyush kaul]

thanks people..it helped a lot...:)
i talked to the people at BOTS, heading there tomorrow to clear all the doubts i have...:)

Piyush

[RT]

I ride a 17-inch frame KHS Alite 1000. I'm 5 foot 10 with longer limbs (than torso), similar to how Shreeju describes his build. I also had a lot of OTBs initially. But thats because I was running a 110mm flipped stem on inclines. I could hardly complain :)

Personally, yes its taken time to experiment with the fit of the bike (and I continue to do so with different setups on different terrain) but I wouldn't trade the bike for a larger size for a million bucks. Why? Because as Georg and George mentioned, it makes for awesome handling. It feels alive on technical terrain and now I find slightly larger bikes really sluggish.

A small bike can be tweaked to fit you with different seatposts (longer, more layback) different stems (longer, shorter, riser, flipped, etc.) and even bars (riser bars, flat bars, wide bars, etc.). There's sooo much more to it than just adding a longer seatpost. 

For example, in Shreeju's post he mentioned he raised the seatpost very high and then to counter the long reach, he moved his saddle forward. I think I remember Doc Rao once posting an interesting analogy having to do with trying to do a squat while keeping your back dead straight and perpendicular to the ground (you tend to fall backwards). Its interesting that moving your rear backwards is actually necessary the higher you go or you will end up with all your weight on your arms, on the front end of your bike, resulting in quick OTBs if you don't watch out for it. What I would've done if I had to reduce the reach would've been to move the saddle a little back but move the bars closer to me either through a shorter stem or through riser bars adjusted so that the 'rise' would've been aimed further towards me. 

At least, it really is worth trying out various combinations until the fit is right or you decide to trade the bike. Of course, if you have a larger bike, there is bugger-all you can do. 

Cheers,

Rahul

p.s. All this refers to mountain bikes and hybrids. I have no clue about roadbikes

On Thursday, November 22, 2012 12:41:36 PM UTC+5:30, piyush kaul wrote:

[George's GMail]

Well said. 

... & pretty well the same for road bikes. 

George Joseph

IN Cell: 9483501169

NA Cell: 847-859-9591

-sent from my iPhone 4S

[deepakvrao]

Yes, like George said, well said.

Reach is adjusted by stem and NOT by moving the saddle forwards.

Analogy I had given was to try and stand with feet AND bum against a wall and bend forward. If you don't have something to support your hands on, you will tend to fall forward, so you NEED to put weight on your hands. Now, if you move your feet about 8-10" AWAY from the wall, still touch your bum to the wall, and lean forwards, you do NOT need any support for your hands, as your bosy will be well balanced WITHOUT any weight on the hands. So, if you feel too much weight on your hands, paradoxically you in fact need to move your saddle BACK and not forwards.

[George Joseph]

You can move your saddle forward as long as when your knee is not TOO forward.

The way to check this is to sit on your bike like you normally would. 

Then pedal till one of your crank arms are horizontal.

If your take a look at where your knee cap on that side is - it should never be in front of the axle of the pedal attached to that crankarm which is horizontal.

This will ensure optimal power delivery and prevent messing up your knees.

That should be your first adjustment. After that if you feel cramped you should get a longer stem. Or if you feel too stretched out get a shorter stem.

That being said the "second rule of thumb" is that if you look down while riding seated your handlebar should block your line of sight of the front axle.  Again this is a just a rule of thumb.

The more behind your front wheel axle is the stem the more responsive, while the father ahead your axle is of the handlebar the more relaxed the steering.

So in general start with the height of your saddle.  If you put your heel on the pedal and put it at the very bottom, there should be a tiny bit more you can straighten you leg out.

After setting your vertical height, by moving the seat post up and down,  then you do the fore/aft adjustment on your saddle.

Then finally your stem length adjustment, followed by your stem rise or angle. The angle should be such that your handlebar is a few inches at peats lower than your seat post.

This will generally work for both off and on road bikes. 

The important thing is to listen to your body and dial in your adjustments over time. 

Good luck..

Sent from my iPad

[Uday]

Rahul,

I agree with your point about experimenting. You could do all that. After having bought the bike, there is something at stake.

On the other hand, if you are trying to buy a bike, why invite all the trouble. You can simply buy what fits you, than to make umpteen adjustments.

+Uday

[Shubhashree N S]

Hi George,

That was a very useful piece of information. Thank you.

Shubhashree N S

[deepakvrao]

Yes largely correct, but to just be more specific, knee CAP can be ahead of pedal axle. It's the tibial tuberosity that should be aligned with pedal axle as per the [controversial] KOPS theory.

[George Joseph]

Yes its not quite the knee cap ... but its pretty close.

But as far as the 90 degree (KOPS) its quite basic high school physics - or basic angular momentum - which is always 90 degrees to the applied force

Its the same principle for pendulums, fulcrums, , etc, etc, etc

The crank arm is basically a lever.

When the crank arm is horizontal, its momentum is moving purely vertically.  To aid this we can push down on the pedal - the maximum force as a vector is applied at 90 degrees to this lever.

For this to happen the shin bone must contact the pedal at 90 degrees to the horizontal plane of the pedal.

Anything where the shin bone is not ~90 degrees (over or under) to the horizontal crank arm results in less force being transmitted. 

George Joseph
gjos...@gmail.com
IN cell: 91 94-83-501169
NA cell:1-847-859-9591

[RT]

Indeed. Nobody said you shouldn't buy the right size. 

However, even after buying the right size, it actually takes time to get the right 'bike fit'. They are two very different things. Sizes differ and geometry differs from brand to brand and design to design. No matter what bike you buy, over time you should ideally tweak the bike fit to suit you just right. It doesn't stop at simply raising the seatpost to feel comfortable. 

Of course if your bike is absolutely perfect from the word go, you're a very very lucky (and rare) individual :)