goldfinch

My primary road bike is a Trek Madone, 43cm with 650 wheels, effective top tube of about 48cm IIRC. I am very short, shy of 4'11". The stem on that bike has next to no rise that I can see and it measures from center bolt of the headset cap to the center of the handlebar slightly less than 60mm. I assume it is a 60mm stem.

I recently bought a used Terry Symmetry (44cm, 650 wheels, effective top tube just short of 50cm IIRC) as a bike I can ride anywhere and park anywhere and toss on the bus racks, that kind of bike. The Symmetry is slightly too long in the reach for me as compared to the Madone. I will say it is a nice and stable bike and not near as twitchy as the Madone. I measure the stem at 70mm. I would like a shorter stem to bring in the reach a bit. I am riding both bikes with the saddle about level with the handlebars.

Questions:

How short of a stem can you go without a big negative on handling?

Neither the Madone nor the Terry have any angle to speak on on the stems. If I get one with a certain amount of rise, does that change effective stem length? Or, is stem length measured differently if the stem is angled?

Unrelated to the stem question, I have another minor question. The tires on the bike are 650 x 28, made by Terry. I like the wider tires. The side of the tire reads inflate to 110 but doesn't give a minimum. I put 90 pounds in them. Can I go lower? I weigh about 105 pounds.

cny-bikeman

1. The shortest you can go is 40mm, which will make the handling slightly quicker, but not very noticibly. People sometimes exaggerate the effect of changing stem length on steering. The difference in steering is proportional to the change in distance from the center of the fork colum to your hands, and in the case of going from 70 mm to 40/50 mm that is a 3.5/2.5% change. Perhaps you have looked already, but to see the options from 40-50mm use this Google search threadless stem (40mm OR 45mm OR 50mm) (28.6 OR 1 1/8) -bmx
2. Distance and height from saddle to bars are related but separate issues. That being said geometry would indicate that more rise would put the bars slightly more toward you as well as putting you more upright. (use the calculator in the post below)
3. https://www.dorkypantsr.us/bike-tire-...alculator.html (you can Google bicycle pressure calculator for other pages and even apps).

pmt

My juniors use 50 and 60s and seem to do ok.

But a stem off eBay is about ten bucks, and it's maybe five minutes to change it, so why not buy a few and try them out?

Crankycrank

Short answer to calculating stem length with different rise is here as long as you know the angles. https://www.brightspoke.com/t/bike-stem-calculator.html
I have found that manufacturers can vary slightly as to how they measure stem length but usually it is length from the center of stem to a parallel plane of the handlebar clamp center. 70mm is already fairly short for a stem and you could probably go to a 50mm without much difference in handling but really hard to know without actually trying it out. Even shorter may be a possibility. As a very general rule the shorter the stem the more twitchy steering becomes for most bikes but not always the case. Most bike shops have boxes of cheap stems that were traded from new bike purchases and it might be worth asking if you could try some out before buying since they usually can't get rid of them fast enough.

Ooops. Just noticed two others beat me out with good answers while I was writing this but hopefully this will help as well.

goldfinch

OK, I will try a 40 or 50 cheap stem and see how it feels.

On the tire pressure issue, the calculator assumes a 700 tire. Assuming the real issue is width, the minimum pressures for me for the 23mm tires is far below the minimum pressure printed on the tires on my Madone, which is 87 pounds. I do run them at between 85 and 90 pounds. The minimum pressures according to the calculator for 28mm tires would be even less. I am talking thirty some pounds for the front and 50 some for the rear, which seems way too low. So, I don't know how low I can go when there is no stated minimum. Would 75 pounds be reasonable? It is still quite a bit more than the calculators show.

cny-bikeman

I don't see a problem with that. The minimum is probably printed in part to avoid people risking rim damage, and even if you're light you don't want to go too low, as it's much easier to suffer tire or rim damage.

P.S. On a new bike it's important to make sure your seat position is proper before deciding on the stem. Assuming your position on the Madone is dialed in, if the Symmetry has a different seat tube angle you will require a different saddle rail position on the post to have equivalent position over the bottom bracket.

Crankycrank

+1. I like to run mine as low as possible for a comfy ride without going so low that potholes and such will ruin my rim or cause snakebite on the tubes so at 200lbs I will usually run around 110psi. Obviously the OP could go lower being half of my less than svelte weight. If you like to use lower pressure just notice if it feels like your tire is bottoming out over bad road surfaces and add air as necessary. It takes getting a few miles in to find the sweetspot for yourself.

goldfinch

Yeah, I thought about this. I am fitted to the Madone but not to the Terry. I have to think about whether I can fit myself. Seat height is pretty easy for me to figure but the saddle rail position on the post is much more difficult.

I'll drop the pressure down to 75 and see how it feels. I just got to the Withlacoochee trail area in Florida and I'll try it out of the trail today. And bring and allen wrench to mess with my seat too.

cny-bikeman

Probably all you need to do is drop a vertical line from the nose of the saddle and see how far that is in front of the bottom bracket center. Duplicate that distance on the 2nd bike.

MikeWMass

I am always a little puzzled about the discussions on the effect of stem length on "quickness" of handling. It seems to me that, at speed, a bike is not really "steered" the way, for example, a delta trike is. You lean the bike (either by weight shift or countersteering, which is another whole discussion) and the front wheel is "steered" enough that you keep going rather than falling over. If you really had to steer, you would not be able to turn while riding no hands. Also, when you move from hoods to tops to curves the lever changes by up to a few cm, but the bike handling does not. I have changed my stem length over a 30 mm range and various rise angles on my current bike, and have not noticed change in handling. Conversely, bikes which have seemed to have quick handling have been more difficult to ride no hands than bikes with slower handling.

fietsbob

in trying to get the Fit right, whether it changes the reaction time to miss a wee road hazard is unimportsnt.

first get the bike to fit right... might need a zero setback seat post too..
like thomson saddle rail clamp is directly on top of the post..

External Bearing BB resolves Mike's red herring..

MikeWMass

I accidentally posted that in the wrong thread. I removed it and put it in the correct place, you must have seen it in the 45 seconds it was here. Sorry!

goldfinch

Thanks for the tip. I should have done this before I went for a ride.

I took it for a 38 mile ride today. The first 30 miles were great, after I fussed a bit with the saddle. But my feet went nuts with numb toes at around mile 30 and my rear end started to be uncomfortable a couple of miles later so I limped home. I don't know if it was a fit issue or a pedal issue. On the Madone I use Speedplay and on this bike I am trying to not use clipless at all, to facilitate ease of use. I might swap the pedals for the Ergon's that I have on my hybrid to see if it makes a difference.

In some ways the long reach was not bad. At least it wasn't bad for a 38 mile ride. And, I could ride the tops which I never do on the Madone. But riding the hoods is kind of iffy so I still think I need a shorter stem.

I may need to have someone help me with fit.

goldfinch

My fitter on the Madone considered zero setback but it doesn't work for me, even though I have reach issues. For some reason I need my saddle back quite a ways. Maybe long femurs? Don't recall.

goldfinch

Okay, I dropped a line and to have the Terry match the Madone I would have to have the seat come further forward than the maximum. I brought it to the maximum. Maybe fietsbob is right, I will end up needing a zero setback seat post. Dang you guys are good!

I think I need a fitter if I plan to ride this more than 20, 30 miles in a shot.

cny-bikeman

You may be interested in this discussion of fit. https://sheldonbrown.com/kops.html
I am not in Mr. Bontrager's class when it comes to fitting but I happened on some of the same conclusions about knee-over-pedal not being the best approach. I'm not actively in the business any more but I've roughly used what I could cull from the article in adusting my own fit with good results. Note near the end of the article he contends that even femur length does not necessarily correlate to saddle position.

goldfinch

This is tough. I went for a short ride with the seat further forward to more closely match the Madone. It was terrible. I kept wanting to push myself further back. I ended up putting the seat further back again even though it does not match the Madone in seat position. To experiment, I dropped the seat height to more closely match my hybrid which also wears platform pecals and I can't get it low enough, the seat tube is too long. Ack. Some of these issues will just have to wait until I am somewhere with tools and where there might be a fitter to work with. I am getting frustrated.

I am going to go for a 15 mile "leisure" ride tomorrow with people in my rv park. I am going to ride the Terry even thought the fit is off. I can stop a few times and mess with the seat. I'll wear my thickest soled shoes to make up for the fact that I'd like to drop the post a quarter of an inch.

Today I rode my Madone on the same route I took the Terry on yesterday. Needless to say, I was a lot more comfortable. However, I sure do like how the Terry takes bumps and ridges in the pavement as compared to the Madone and how it almost steers itself.

pierce

at 4'11", I suspect you want to use the shortest crank arms you can get, like 165mm rather than the more common 170-172.5-175mm. of course, this depends on how long your legs are too. my daughter is 5'4" but has a 34" inseam, so she's all leg.

goldfinch

I have 165 arms on both bikes. Actually, on all my bikes. I even swapped out the crank on my hybrid to get the shorter arms. With advice from all of you.

Bezalel

It's more important to determine where your sit bones rest.

pmt

My juniors have cranksets of 160 and 155; had to have them machined, but the results were worth it.

goldfinch

Well, I got a 50cm stem and put it on the bike today. I took it for a short ride. Oh baby, this is much better! Much better. I'll try a longer ride in a few days.

goldfinch

I took the bike for a 50 mile ride in the heat yesterday. It went well. The bike isn't the best fit for me but it isn't meant to be a long distance bike but a spare. I wouldn't want to take it for 100 miles. But 30, 40 miles would be perfectly fine and perfectly comfortable. The 50mm stem makes a huge difference.

Frankly, what I now dislike about the bike are the brakes. They are not as easy to pull and not nearly as effective as the brakes on my Madone. I find them a bit hard to operate from the hoods but fine with the extra leverage on the drops. It might just be because they are a lower level component. Is there some kind of adjustment on the reach of Tiagra brakes? I can't tell by looking at them.

fietsbob

some rubber wedges come with new bikes , so the lever doesnt come closed on top as far..

check LBS and see if theres leftovers

ksisler

Post a pix of the front brakes as they are on the bike right now and one of the levers on the current bars. Include the model and brand of each. Also tell us if the reach of the current levers are too big or too small. Helping from a factual baseline is much easier than just rambling on the topic.
/K