lungimsam

I have read that changing things more than a coupla mm's at a time can cause injury.

Yet I am sure that some people own and ride mountain bikes, race bikes, and cruiser bikes which are vastly different in fit measurements and measurement behind bb, bar reach and heights, etc. I would think that the mm adjustment principle would apply to riding different kinda bikes, too, since the fits are different. Yet I am sure people do it and they are just fine.

So, is this slow, mm, fit adjustment thing a myth? Do I have anything to fear in making bigger adjustments if a current fit isn't working out, or riding my race bike in the morning and then getting on the upright bike in the afternoon?

chasm54

No, you don't have anything to fear unless you do something silly like setting the saddle far too low or too high. And certainly switching between bikes is no problem at all.

However, the advice to make small incremental adjustments, and to make them one at a time, is sound. A few mm difference in saddle position, for example, can make a much more radical difference to how you feel on the bike. And if you change more than one thing at a time it can be difficult to work out which change is making what difference.

fietsbob

Absolute highest performance requirements of athletes, have a mythology of their own,
that is just not applicable to the general population.

Wilfred Laurier

Mal-adjusting in the extreme can cause injury, but not because you changed it all at once. If you do a double century with your saddle 6" too low you will get sore knees no matter how many incremental adjustments you made to get it 6" too low.

wahoonc

This...

I have multiple bikes with multiple riding positions all are close and but not similar. I am not a top notch athlete, but I do ride quite a few miles a year. I can tell very quickly if a bike is not comfortable to me, I stop, make the adjustment and continue the ride. I have a couple of dimensions that are critical to ME, but may not matter to someone else. Yes a few mm can make a difference, but if a bike is set up close to begin with making a change is not going to "injure" you. FWIW I have been riding over 40 years, fit used to matter more than it does now.

Aaron

Retro Grouch 

I'd think the opposite would be much more likely.

When you acquire a new bicycle, the seat height is likely to be an inch or two off. Do you think it would be better for your knees to adjust it close to ideal immediately or to ease it up a millimeter or so each day for a month?

MetalPedaler

Another myth of cycling culture.

I take just the opposite approach: I make changes that are plenty severe enough so that I'll be able to tell the difference. When I find what seems to be the better position, them maybe I'll play around with smaller incremental adjustments over time, to get it just right.....but even then, it'll usually be at least a centimeter at a time- I don't obsess over millimeters- our bodies are far more adaptable than that; and just moving a limb or a muscle slightly will more than cancel out a difference of a few millimeters.

I really get disgusted when I see some prisses obsessing over a few millimeters. It's so ridiculous. I'd bet even the pros don't do that- it's likely the sole province of wannabes who have been heavily propagandized by bicycle industry marketing and others who want their money...and probably does more to spoil their riding experience, than to improve it.

It takes much more than a few millimeters to go from "good position" to "injury"- and even when you're way off, your body will let you know so that you can adjust things, long before you'd get injured. It's not like you're going to jump on a bike and get instantly injured on the first pedal stroke if it isn't set-up to fit just so!

Wilfred Laurier

I have dealt with elite racers who were quite fussy and adjusted their saddle height with a meter stick, getting as close to the mm measurement as they could. I have heard more than one of them say the bike didn't feel right, then when the meter stick came out the seat was 3 or 5mm too low.

The rest of your post is true - the mm don't matter to normal people, and having your saddle or bars less than ~1cm misadjusted is unlikely to be noticed and even less likely to cause problems

Artkansas 

I usually do a fitting session, it consists of make an adjustment, ride to the end of the block and back, repeat as needed. If a longer test is needed, I get it close in the fitting session and then take any needed tools on a longer ride.

chasm54

If we're talking road bikes, most of this is just wrong. A difference of a centimeter in stem length, for example, is significant enough to make the difference between comfort and back pain when spending hours on the bike. People who don't know what they're doing might not notice it, but they'll notice their back hurting. A difference in saddle height of a centimeter is enough, over time, to cause knee problems if you get it wrong. I'm very aware of my position relative to pedals and bars, so I'd notice this pretty much immediately. Pushing the saddle back a centimeter would be noticeable within a few minutes, because I'd find my weight being borne by the narrow part of the saddle and that exerts pressure on the perineum, which is not good.

And I can assure you that some pros do indeed obsess about millimeters. Eddy Merckx, the best of them all, was notorious for checking and double- checking whether his mechanics had adjusted his bike to the millimeter. And these days, with wind tunnel testing and power measurement, tiny adjustments matter. The most aerodynamic position may not be the one at which the rider can put out the most power on their time trial bike, for example, so a lot of time and effort goes into achieving the fastest compromise.

Camilo

Well, you might just be exaggerating for effect, but I don't believe I've ever seen it put in terms of a couple of mm's.

Yes, I've seen the advice made in terms of 1/8 - 1/4 inch or 1/2 - 1 cm at a time, but that's about 5X the amount of adjustment you're talking about.

The advice really is to just do it in small increments and mark things before hand so (a) you actually know how much you've adjusted rather than eyeballing and guessing and (b) you can have a benchmark to return to or go past the other way if the first adjustment doesn't work out.

longbeachgary

For me personally, tiny adjustments are necessary or there is hell to pay. I had my bike in the shop and they raised the seatpost so that they could clamp it in the workstand but when they put it back it was off by less than half an inch. Didn't notice but when I went riding, my knees hurt like hell. Checked the measurement when I got home and sure enough it was not where it should be.

caloso

I'm with LongBeachGary. The older I get, the more sensitive I become to small changes, particularly in saddle placement. Me knees and hips will tell me within a mm or two whether it's off or not.

Bmxovich

Ditto: Once I hit the magic age of 50 my joints became the issue. Everything has to be very close for anything over an hour on the bike. If not a twinge of pain will start, usually a knee or the back. Even changing bibs from thick to thin effects me at times. I hate it.

MetalPedaler

Guess I'm lucky- I'm 50....but I seem to be able to adapt to a wide range of positions/sizes, just as long as they're not totally ridiculous. Of course, I have my preferences....but it just has to be in-the-ball-park. I'm wondering if it isn't the case that one becomes accustomed to the fit that they ride for years, and then immediately notice anything different/feel discomfort, because their body has become so used to that exact position that they ride for years every day; whereas maybe us noobs haven't had our bodies develop that "memory" yet? If that's the case...then a few years from now, I may be saying just the opposite of what I say now; and become fussy about everything being set-up "just right" to the mm on my bike...... But I hope that I stay flexible and easily adjustable instead! (Maybe I'll change my adjustments every few months just to avoid falling into that I-can-only-ride-one-specific-set-up routine!)

Dunbar

In my experience, if it happens gradually over a few rides it's much harder to notice than a sudden change. Even if you've been riding that setup for a long time. I have a very finicky left knee and if I start feeling soreness/pain in a certain area it's virtually always caused by the bike fit changing (saddle slipping down, cleats/wedges moving around etc.)

Large saddle height changes (more than 2-3mm at a time) are most likely to cause injury IME unless you take it easy for the first couple rides and ride at ~70% of your normal pace (like many fitters recommend.) Saddle fore/aft, reach and bar position changes are less likely to cause immediate injury IME. I would still make slow changes though to reduce the risk of injury. I threw my back out a week after a fitter stretched me way out on the bike and was off the bike for a week recovering.

Machka 

I ride several different bicycles, yet my fit on all those bicycles is the same or very close to it.

I also ride a lot, and the adjustments can come down to millimetres.

However, if your bicycle is obviously set up very badly for you ... for example, if your saddle is way too low or way too high ... you will want to make a larger adjustment. If certain fit elements are significanly out, it's more important to get things into a ball park range as soon as possible. It's when you get down to the almost right stage where you'll find tune in mms.

MetalPedaler

I went for a walk last night. My shoulders hurt by the time I got back (very unusual)- I conclude that my belt may've been 2mm too high on my waist, or my shoelaces may not have have been properly torqued.

No wait! Maybe sometimes stuff just happens- but when it happens on a bike, we attribute it to improper fit!

Wilfred Laurier

scoff all you want

but the problems we are talking about are the ones that happen every time you ride
then go away when the fit is changed

if every time you wear a particular pair of shoes you get sore knees
but do not get sore knees otherwise
that is more than stuff just happening

MetalPedaler

Thanks! (I have license...I have license..nyah-nyah-nyahnyah-nyah!)

Nah, I know. I'm not trying to belittle legitimate fit issues...but I do think that there are some people who are way too sensitive or hypochondriacal.

sreten

Hi,

Start off with very big adjustments and then keep halving them.
Don't start with small ones, you could be miles away from whats needed.
Stop when you can't tell any real difference, you will be very near ideal.

Clearly don't ride very far for the large adjustments, go on immediate feel.
The smaller the adjustment range, the more riding you'll need to do.

As for small differences away from ideal fit causing injuries,
that is clearly nonsense and a total bike-fit myth.

rgds, sreten.

MetalPedaler

Exactly!

When I got my first bike, after 30 years of not riding, I started off by trying the seat really low....then really high. It helped me to figure out that near he higher end was where the ballpark would be. I then played around in smaller increments near the higher range...and got it just right quite quickly. Ditto with seat fore and aft. I tried it all the way forward; didn't like that. Then all the way back....that's better...then put it in the middle and started working my way towards the back until it was too much...then went the other direction a little...and VIOLA[sic]!

If I were to hop on a strange bike ight now, without taking any measurements off of my current bikes...I could get close enough to be comfortable for a long ride, just by putting the seat high enough so that my leg is slightly bent with the pedal in the 3:00 O'clock position; and back so that I'm a little behind KOPS....and as long as the top tube/stem were of decent size so as not to stretch me out too much, I'd bea happy camper..er...pedaler.

Machka 

If you only ride around the block a couple times a week, or do a short dash to the grocery store now and then, you can get away with riding a bicycle that doesn't fit.

But if you ride centuries and long distances quite regularly, you want a bicycle that fits very precisely.

Velo Dog

I'm with this guy. If big changes guaranteed injury, we'd all have to set all our bikes up identically or every time you hopped off your road bike onto your mountain bike or onto a cruiser to head down for coffee, you'd rupture your spleen or something.
As for random aches and pains, wait until you're in your 60s. Then you'll have something to talk about.

Machka 

But the thing is ... I ride a tandem, a mtn bike, and several different kinds of road bicycles ... and the saddle height on each of them is the same, and the distance between the nose of the saddle and the handlebars is the same.

Just because you ride different bicycles doesn't mean they fit differently ... the fit should be the same, or very similar, between them all.


Go measure your bicycles and see how similar your setups are. If they are not the same or very similar, you might want to give some thought to why you find one bicycle more comfortable than the others, and why you like riding it more than the others.