Bike size question
 

Thinking about a new bike for my wife. Coming down the very long Japanese mountains she sometimes has problems braking. Her Surly LHT has mustachio handlebars so the brake levers are horizontal; but still far from perfect. So the question: how do you size a bike such as the one linked because the crossbar is on an angle?

https://www.jamis-japan.com/sequel-s2.html

Looks like the same sort of sizing as MTBs. So whatever MTB size she rides.

We only have Surly LHT so no idea about mountain bikes.

How tall is she?

She is 1m 59cm.

I'd guess 15" based on standover height.

At her height, the mustache bars may be the root of her braking problem. She would likely be more comfortable using the brakes on a bike with conventional flat or, better still, swept-back bars. A folding bike might be ideal.

Bikes should be sized by reach, not by seat tube length.

You can raise and lower the seat however you want. Seat tube length is irrelevant.

How does changing to a folding bike have anything to do with how hard she has to squeeze the brakes? :foo:

The root of her braking problems is her brakes.

Hydraulic brakes can be operated with one finger. She should ditch her high friction cable actuated brakes and change to hydraulic brakes.

If her bike is rim brake, she should change to V-brakes.

It isn't irrelevant when you are quite short.

15" sounds like the correct size. Then you adjust with stem length.

Hi waddo, I ride bikes with all kinds of brakes, rim canti and rim v brakes as well as mechanical disc brakes. I commute and tour with weight on bike, and yes, disc brakes really do have more powerful braking, so less finger effort needed for stronger braking vs rim brakes---
BUT, without knowing the condition of your wifes LHT, one can markedly improve rim brake power by making sure the brakes are set up properly, the rims are clean, the pads are clean, and most importantly, using softer pads like koolstop salmon coloured ones , that are easier on the rim and have noticeably stronger braking power.
Some people also set the brakes to engage too soon in the lever movement, thinking that they need the lever to engage sooner so they feel it is safer. I've always found that not having the pads engage too soon gives your fingers a better leverage for stronger braking, or rather, when the lever engages very short in the "throw" of the movement, our fingers are not as strong when only slightly flexed.

its also not uncommon for pads to not be perfectly aligned, or cantis not set up properly with the cable setup.

bottom line though, disc brakes, even mechanical ones, give a very very noticeable increase in braking power for a given amount of finger pressure. I noticed it right away when first touring loaded up with my surly troll with mechanical discs in mountainy areas. Ive toured lots in mountains over the decades, and discs just are so much more relaxing, because you can slow down so much faster and easier than with rim brakes---so yes, she would appreciate a disc bike in this regard.

that said, a lot of people are wary of using the front brake strongly, and favor the rear brake, lots of my riding partners do this and it just doesnt slow the bike down as well as using the front very strongly. Lots of people are afraid of flipping over the bars, and this contributes to this behavior.
Also, dragging the brakes non stop overheats things, and always results in less braking power, rim or disc, so this is a big factor with lots of people also.

no matter, I really hope you find a solution that your wife will be more comfortable on long downhills, thats all that matters.

disc brakes do come with having to learn new mechanical skills, but that is doable, learning new stuff-- I know I had to when I got my first disc bike and it was sometimes frustrating.
cheers

oops, forgot to add info about the sizing
My partner is about 5'1, so a bit shorter than your wife, and her Surly Troll is a XS size.
XS frames have generally been a much better fit for her ("smalls" have always been just a bit too big) and then of course stem and bar choices make up the differences to get things to fit for a given individual and the types of bars (just bar choice can make a huge difference, oneswith rise, ones that angle back with a nice sweep that wrists like more than straighter mountain bike type bars)

but handlebar choice and preference is a whole other kettle of fish in terms of preference , so a big big topic. I ride and have tried all kinds of bars, and just didnt like some, especially for any sort of longer riding, where others have been great

if looking at new bikes, be sure to use her LHT's gearing details as a reference, if she is happy with the low gearing of her present bike, make sure that a new bike has at least the same low gear.

Like you, I'm guessing based on the limited info given.

She's a hair over 5 feet tall. Millions of women of that height have used cable-actuated rim brakes since the year dot. Very few of them have had bikes with mustache bars, which require an unusually short stem even for men of average height for the (road-bike-style) brakes to be comfortably accessible.

There's a good chance that a folding bike of decent quality would be a cut-to-the-chase solution, regardless of the brake type, since a good fit would be easy to achieve and the bike would likely have the brake levers positioned where she could use them comfortably and efficiently.

Ask a small person how much “seat tube length” and, more importantly, stand over height is? No, you can’t “raise and lower the seat however much you want” if you can stand over the bike without smashing sensitive bits on the bike every time you get on and off.

For the average person, they will never run across the problems that small people have to endure when it comes to bike fit.

How steep is the hill? A really steep hill can be a problem. There is a hill a few miles from my home that I can't stop my rando bike on that hill.

I agree with Djb, Koolstop Salmon pads could give better braking.

Cable brakes are just fine, assuming that there is not a kink or frayed cable inside the housing, or other impediment to nearly friction free braking.

Does she have unusually poor grip strength? Maybe the mix of levers and brakes can be tweaked. I have road (short cable pull) brake levers on my folding bike and mini-V (85mm length) Tektro brakes, the brakes are almost too good. I have to be careful that I do not hit the brakes too hard on that bike.

Try different bar and stem combination before changing bikes. I agree with Yan, reach is a bigger issue than seat height. If she can pedal that bike just fine on flat ground, bike size is not the problem.

definitely the 15" would be my first choice for her based on her height, assuming average body dimensions for that height.

Even with unaverage proportions, what other size would work better? Long legs just make reach a bigger problem. Short legs makes standover a problem.

Height is generally the single most useful number for boke sizing unless it is a middle to large frame with a tall headtube.

Too little info about her bike, what brakes?? Show pics. Rim brakes are poor, especially on long hills. IMO. For disc brakes on whatever bike, the answer is TRP cable Spyre calipers.
You can move those levers to the closer swept grips, pointing down. Maybe need to switch to 4 finger levers. Maybe a riser 80d swept bar is better, that's all I have on 3 bikes.
> The bike linked is not the answer IMO. 1x and straight MTB palms down bars are horrible with NO back position relief possible. But I guess it is possible to put a swept bar on it too.
15" is ridiculous, get serious, she's 5' 2.5".
If you really want powerful NO fuss brakes, get a SA XL drum brake on the front. My first one is still like new, 32,000 miles. If she already has a SON dyno, then that's a conflict. LOL

https://cimg6.ibsrv.net/gimg/bikefor...0aa203f445.jpg

The reason that I agree with Yan on reach being more important that seat tube length is that it is easy to adjust seat up and down a lot. But reach is a lot harder to adjust for, as the range you can fit with different stems, steerer tube spacers, and handlebars with different reach is a lot smaller.

Cyccommute is also correct on stand over height, but since most bikes now have sloping top tubes it is rare to find a bike where standover height is a problem. My rando bike has a horizontal top tube, but those are now quite rare.

Decades ago, when top tubes were horizontal, bike shops often fit bikes based on minimal stand over clearance. In that era there was a common theory that you wanted a fist full of seatpost. If you wrapped your fist around the seatpost and had several extra inches of exposed seatpost, that was considered too small a frame. But that size philosophy is no more.

Based on that historic fist full of seatpost sizing system, my rando bike with a horizontal top tube actually should be one size bigger, but that would have given me an uncomfortably long reach. Earlier this year I put different handlebars on it to shorten the reach by about an inch. I built it up a decade ago and since then I have not liked the reach, but there were not many stem choices that were shorter. This year my right brifter needs to be rebuilt, and I wanted to change to a suspension stem, so decided this was the perfect time to go all out and change the handlebars to get me a better reach too. Much improved.

That said, for the person that has poor braking in the initial post, I would focus on fixing the braking on the existing bike, not concluding that it is the bike's fault.

Thanks for that very informative and detailed reply.

I'm 5'4" and have sized many small women to bikes going back decades. It is simply not true that sloping the top tube creates all the necessary standover height. And that's because most bikes have the top tube sloping up to the top of the head tube, and head tubes have to be the height of the fork plus headset plus at least 3", and that means that the top tube starts much higher than most short people's inseam, even on very small sized bikes. And then it slopes down no lower than where the chainstays connect to the seat tube, so that's another limitation.

The net effect is that someone with a 28" or shorter inseam is going to be sitting on the top tube almost no matter how small the frame is once then get in front of the saddle nose.

The direct effect to this thread is that a 5'2" woman is almost guaranteed to not have any standover if the tube starts at the height of a typical 17" frame. And, the bars will be possibly too high and the reach on the long side.

So claiming that it all comes down to reach is frankly ridiculous. It is reach, standover and bar height that are impacted. 17" would almost never be an appropriate size for someone that short.

For taller people or bikes with undersized wheels such rules of thumb might make sense, but not for bikes that are right up against the limits of their tire size.

Re tire size, I failed to mention that my 5' 1" wife's XS frame has 26in wheels, which eliminates toe strike and this size wheel does work well in small frames.

A dying standard I know, but handy in this situation.

The OP made no mention of the person described on this thread as having any difficulty with fit on the bike, other than lack of braking power. No mention of poor fit. The person described by the OP had an LHT, the smaller sizes of that bike were 26 inch wheels. When I read the post, I knew she was on a 26 inch wheel bike. I thought that the fact that Surly designed their LHT that way was common knowledge, this being the touring sub-forum, so I saw no reason to mention it.

I recall several years ago a small woman won the world time trial championship, there was some discussion of difficulty fitting her to a 700C time trial racing bike. A smaller wheel would have made more sense, but the cars that carry spare wheels on race courses only carry 700C, thus a smaller wheel could not be swapped out. Thus, she raced on 700C and building a bike that met UCI rules for her was enough of a challenge that someone wrote about it. I do not even know if smaller wheels could be used with tubular tires, that is a topic I have no reason to think about.

I can see where someone 5'1" or 5'2" might not be able to fit on a 700C bike very easily unless it is a mixte frame. And when I think of small frames, I think of mixte frames. Decades ago when I worked in a bike shop, we sold mixte frame bikes for smaller people.

Several years ago when I was out for a walk, a few blocks from my home I saw an old mixte frame bike leaning up against someone's garbage can waiting for garbage pickup. The bike looked like it had low miles and was quite old but in good shape. Covered in dust and cobwebs, must have been stored in a garage for decades. A friend of mine volunteers time at a bike charity. I thought I should wheel the bike home and ask him if the charity might want it. They fixed up donated bikes to give to under-privileged kids. By the time I got it home I instead was thinking this would be a good bike to put on a home trainer instead. That way I would not put wear on the drive train on one of my other bikes. That was over a decade ago, that bike is sitting about eight feet behind me right now, rear wheel on a trainer. I had to replace a bearing in the bottom bracket and find a really tall seatpost to put on it to fit me. Nice 1980s Bianche mixte frame 700C flat bar bike. When I think of small framed 700C bikes, I think of bikes like that. When I had shoulder surgery, that bike was the only way I could stay in shape for several months, the surgeon did not want me to drive or use a tread mill or do anything at all for several months.

These sloped top tube style frames have so much crotch clearance that even a child could straddle an adult bike. That doesn't mean the child then fits that frame. The reach would be too long.

"Seat tube length" is completely useless for sizing on this style of frame. They must be sized with reach.

waddo’s wife is roughly the height of a child. My wife (of similar size) knows from experience how little “crotch clearance” bicycle have. If the rider can’t stand over the bike to begin with, there is no need to go checking the reach.

You don’t seem to understand that seat tube length or, more specifically, the frame size and reach are somewhat related. You probably won’t find a small sized frame with the reach of a large sized frame.

As to “sizing by reach”, how would you propose to do that? Consider, some is standing in front of you wanting a bike. If you ask them what their “reach” is, they would stare at you as blankly as a new chalk board. Ask them how tall they are and you can start with a frame size and then refine by reach…although “reach” is not a variable in bicycles as many would make it out to be.