I’ve recently got back into MTBs (old enough to know better but loving it).

I’ve gone through a selection of second hand bikes in the last year and when I find ‘The One’ – I’ll splash out on a new one but at 5’8″ .. with even shorter legs .. I can’t make up my mind whether small or medium feels best.

On flat, single track stuff, I feel better and faster on a bigger bike but as soon as it gets more technical; I wish there was a bit more safety gap between a hard metal and my bits!!

I’ve tried short stems etc on a medium frame and stretching the cockpit of a small frame, the only thing I haven’t tried is longer legs …. but they don’t come up often in the classifieds.

It would be nice to get to one bike that I can ride for long enough to get used to – any suggestions?

Quite subjective I’m afraid, as there is no Standard for what constitutes a small or a medium. In fact, some manufacturers smalls measure up more like other manufacturers mediums which can confuse things!

All I’ll say is that at 5ft8, you are more than likely going to be either a small or a medium… HTH! 😉

Seriously though, nothing beats trying a few out for size, only you will know what feels good. I’ve never found a Santa Cruz that fitted well for instance, cos I’m between their Medium and Large sizes, yet on most bikes I’m smack bang on a medium.

All I’ll say is that at 5ft8, you are more than likely going to be either a small or a medium… HTH!

Brilliant!

I don’t know why I hadn’t worked that out myself.

😀 😀

Brilliant!

I don’t know why I hadn’t worked that out myself.

Even with a wink 😉 you didn’t detect the irony? 😕

Must try harder next time then!!!

Of course I did – that’s why I put the grin at the end.

Bloody forums / text – so hard to get the intonation right.
😕 8) 😮 👿 🙁 😀 😯

(If you get my meaning).

Short legs means a longer body (all things being equal). So, like my son, I suspect a medium will feel a better fit (virtual top tube). Stems can always be changed – he rides a Medium with a 50mm stem and loves it.

I’ve never thought of it that way but it makes perfect sense. That would explain why when I have comfortable standover height … the bike feels cramped.

I’m 5′ 7″ 30″ inside leg had a number of On One’s 18″ just didn’t feel as good as the 16″ for me. Still have the 16″, the rest long gone…

Depends a lot on the particular bike, I think. From the sounds of it, you want a small frame but one that has a long top tube, if that makes sense. This will give you the standover height you need, while being a bit longer for the rest of your body…You should get an idea by considering frame measurements of different bikes.

Have a good look round and the sizing tables, something like an On-one 456 has a very low TT so much better standover, some Santa Cruz’s are the same

Look for a ‘small’ frame ie 16″ ish with a long top tube.

eg if going for a hard tail On Ones at the budget end and Cotic Soul at the expensive steel frame end. The On One 16″ is a bit longer than the Soul small but they are about in your ball park size. If you want to get them more set up for distance just make sure you have a nice 410mm long Thomson post and consider things like bar ends etc and nice wide-ish bars – eg 700-710. Stem wise you’d be looking at 60-80mm with the above. That is just a first (educated) guess but should get you in the right ball park. I prefer a smaller frame that I can adapt rather than a gate I am trying to make fit. Short top tube frames are no good for me as I prefer short stems and have a long body so feel hunched.

I had a small Mongoose Teocali, which felt fine. I’m 5’9 with a 30″ inside leg. The more confident I got on the bike the more I wanted to change it to make it better going down hill, so ended up shortening the stem to 50mm from 65mm and widening the bars from 711mm to 760mm. Now although this made the front end feel better , the cockpit felt slightly small. So have now purchased a medium Specialized Stumpjumper fsr which gives me a slightly larger cockpit.

Medium bikes usually come in at 17″ or 18″ and top tubes measure up different on each brand so the only way to know for sure is to try.

I’m 5’8″ too and have similar issues, don’t get me started on buying jeans…
Anyway, I prefer my bikes on the smaller side as my riding leans more towards DH/Freeride than xc, although I do like to ride xc a fair bit too.

I used to have a medium Heckler which felt fine, it was my first ‘mid-travel’ bike. I sold it not due to the size but found it wasn’t burly enough really.

I then had a Small sized Giant Reign which I have had for a couple of years now and have gotten on with it really well to be honest. It is a little on the short side in TT-length for xc and stuff, and its not helped by the fact that I consider any stem over 50mm to be barge-like.
Saying that though, I’ve found that if I slid the seat a little further back then all was good. It still wasn’t an ideal climbing bike but you have to compromise somewhere.

I recently, as in two weeks ago, bought a Nukeproof Mega to replace the Reign. The first one I had a go on was a CRC riders Medium just around a carpark at Innerleithen. It felt spot on really but the the trouble was, it was just a car park so I couldn’t tell how it would be on the trail.

Recently, a small sized one came up on ebay for a bargain price and I couldn’t say no. I weighed it up and compared geometry to my Reign and decided it would probably be ok. Having bought the frame and laid it on top of the Reign with the BB’s together. The front end is actually longer effectively but its countered by the steeper seat tube on the Mega. So I figured it would all even out essentially.

Riding it at Woburn, which is jumps and drops and short DH runs, it is blummin fantastic. I already felt more at home on it and was jumping further and better than before.
Last weekend I went for a local xc ride, and felt like I was sitting on top of the bars. I slid my saddle quite far back and it was pretty spot on after that. maybe a layback post would sort me out. A longer stem is out of the question, I like my steering.

Anyway, unfortunately like me, you are bang between sizes. Having said that, I suspect that whatever size you got, you could make small adjustments here and there and get used to it. I think it largely depends on the type of riding you do too.

The only real way obviously is to demo, but I know that, that is not always practical. Compare the geo with your current/old frame and go from there. If you are anywhere near Warwickshire or get to Woburn etc, you’re more than welcome to have a shot on the Mega…

Same size as me ,

I’ve always gone for medium frames with a C-T of around 17-18″

Full sussers I have gone for 16″ for tbe last two , 17″ was ok , but felt 16″ more chuck able

I’m riding a 16″ Five at the moment and it’s perfect for me

I’m similar size to you and have found big variations from one manufacturer to another.

My Giant Anthem in small felt good with a 100mm stem and layback seat post.

Conversely my Helius CC in medium feels spot on with an inline post and 60mm stem.

On paper the Anthem and the Helius had almost the same top tube length – 5mm difference – but there’s no way I could ride the Helius with the same 100mm stem and layback post as I had on the Anthem. It suits a smaller cockpit.

The Helius is 18.5″ seat tube length but in reality has loads of tube above the top tube so the ‘on paper’ figures are only really a guide. It has less standover than the Anthem but it’s never bothered me remotely.

The best option is to try as many bikes as you can.

Thanks for all the info – it really does help.

I don’t know if a half hour test ride really gives me a fair idea so hearing from more ‘between size’ people and some bike recommendations is great. I’m sure I’ll get there eventually.