Ladies size

timbo_tim

Hi all

This is potentially going to sound like a stupid question but looking for help sizing my missus up on an MTB. She is new to cycling and I am new to MTB and have no idea how to right size a frame for her!

She's 5'4" so we bought a small Trott MTB (5'2 to 5'6 range) but with what looks a fairly big amount of seat post she is still able to touch the floor with "most of her foot". Non scientifically the saddle is marginally below the handlebars so I reckon there is more height we can get off raising the saddle but I wasn't sure if it's like a road bike where it's better to have a smaller frame and a lot of seat post, or go up a frame size and have less seat post?!

I have a medium on order at Halfords but don't really want to collect and then try and return it once I have built it (would they even accept it?) if it's going to be too big. Equally any thoughts on whether I can return the unused small (but sat in the shed for a few months) to Halfords?

I know saddle height isn't the only determinant of a right frame size but I've no idea what to look for! Sorry for all the vague details but bike is in shed and wife is in bed!!

All thoughts welcome (apart from those critical of me being able to work this out!)

Thanks

The Rookie

Its perfectly normal on an XC/Trail bike like the Trott for the saddle to be higher than the bars. Mine is about 2" higher, I typically have about 7-10" of post showing out the frame (I'm not sure how much you call a fair bit!) depending on the frame geometry.

The seatpost is fine to be lifted as far as the minimum insertion mark which will be leaving circa 100mm in the frame. (The irony being that most seatpost shims are circa 65mm which is fine for the frame to handle).

Correct saddle height is such that with the heel on the pedal (at bottom of the stroke) the leg is just about (but not quite) straight), for many people not used to riding 'properly' that will feel too high for a while until they get used to it.

Begs the question as to what height your saddle is........

Emily Batty (any excuse) who is a similar height to your misses (and a pro-rider) as an example of saddle to bar heights (noting that the stem is a -17 putting the bars as low as they can go on this bike) and amount of seatpost showing.

timbo_tim

Thanks Rookie, that is brilliant, Emily Batty has cheered my day up already!

As for sizing, that is super helpful. I know the theory on saddle height (it's right on all my bikes) but it went out the window as I got confused with it involving females and an MTB!

If the saddle is approaching minimum insertion is it better to go a frame size up (and have much less post on display) or like road bikes is it better to have small frame/long seat post?

The Rookie

No different for a lady than a gent when it comes to saddle height (unless its pastel coloured step through frame with a wicker basket on the front anyway!).

It depends on someone's proportions, saddle height (compared to pedals) is very easy to adjust over a large range, cockpit length (from saddle to grips) has only about a 1" adjustment (sliding the saddle in the post) before you are into changing parts (seatpost for setback or inline, longer or shorter stem and/or different bars) so that is the key dimension in determining the right frame size. A novice rider will tend to sit more upright and not necessarily understand what length a frame should be to get into the right position for 'more serious' riding where the weight is further forward to balance the bike and get front end grip on an MTB) and better climbing posture.

The Canyon 'perfect positioning system' is pretty good you could try out https://www.canyon.com/en-gb/tools/pps/l select bike type MTB, Series Exceed and Model Exceed WMN CF SL 7.9 (closest to the Trott) input her dimensions and then go to the model page ( https://www.canyon.com/en-gb/mtb/exceed ... 9-wmn.html ) and look at the dimensions of that bike (Geometry - down the bottom) and compare to the Trott in terms of C, J and I dimensions, the stem length is similar but allow for the fact that the setback seatpost on the Trott makes it comparatively 25mm longer on the C dimension than you can measure it at. This should give you an idea if you are in the right ball park or not (going up a size will lengthen the top tube - C - by circa 20mm).

timbo_tim

is there anything you don't know Rookie?

The Rookie

Lots........

But if you are an awkward shaped bugger like me (very short arms and legs for my height - nothing like a Gorilla!) this is something I've put some effort into getting a handle on, my first bike was too small as I followed some suggestions that short legs meant a short frame (top to bottom) of course when riding my long torso needed a long(er) frame!

timbo_tim

Remain a little confused. This is how it looks with 10mm off the max saddle height. Top of the saddle is about 90cm from the ground. Still looks small, am wondering if the really sloping down tube is messing it up. Compared to the canyon sizing, saddle height (from saddle to centre of BB) is a minimum of 62cm on the XS small-the tool reckons a S is the right fit but on this it's only just 61cm!

Saddle to pedal drop is less than 1cm short of missus' in seam but can't help thinking it's all a bit wrong?!

cooldad

Impossible to comment without seeing the rider on it. Has she ridden it yet? If it's comfortable it's fine.

timbo_tim

Best not tell her I've stuck her photo on t'internet but this looks about right. As Rookie said it's quite an upright position so maybe a bigger frame might be better? I give up

whyamihere

Saddle height's correct, but the frame looks far too short front to back - She's definitely in too upright a position.

That position would be common for a town bike used for pootling around on, but won't have anywhere near enough room to move around on the trails.

timbo_tim

Thanks, confirmed my fears, now to collect the medium bike I ordered and test Rookie's theory that this bike is worth more as parts as I am going to have to sell this unused small.

The Rookie

She may well need to go up two sizes.

This is the riding position for XC, only a little more upright for XC/trail use.

timbo_tim

thanks though I hope you aren't right, off to collect the medium now and if that doesn't fit I am going to have a nice stockpile of trotts in the shed!! Can't help wondering if we actually have an XS frame by accident, can't believe she should have a large frame.

I noticed there is a stem more than about 20mm on those pro rider photos. So maybe that can fix it all out

The Rookie

That other frame looks more XS than S.

timbo_tim

Who knows what it was, but medium is much better, thanks for all the help! Halfords helpfully seemed open to a possible return of the 2month old unused S/XS, so fingers crossed or I am breaking it for parts!

The Rookie

Just checked the Halfords website, they say the XS is 45cm (18"), not sure where that measurement is but it's certainly not the traditional seat tube, the one in your pic is about a 12-13" based on a tyre radius of 13.5".

timbo_tim

Yep, I found the same (it was 13" from crank to seat clamp) so I don't understand either. Spent Friday measuring everything, I think it must be a typo, the box for the M had a mysterious 41cm measurement on it which matches the seat tube measure of 16"...

Still a bargain though