# Mountain bike size



## Alan Farroll (10 Aug 2018)

Hi,

I have a hard tail mountain bike but seriously considering investing in a trail/xc full suspension. A local shop has this model below at a reduced price but it is a 19inch frame which I think is a size large and not medium. I have had a sit on it and when standing over the bike there is very little clearance between myself and the top tube. I am 5’11” or 180cm tall with a 32 inch inside leg. I am concerned the bike is too big for me. Is that the case and should I look for an alternative with a size smaller in frame?

Thanks in advance

https://www.merida-bikes.com/en_int/bikes/full-suspension/all-mountain/2017/one-forty-700-6343.html


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## Threevok (10 Aug 2018)

If there is very little standover, then I suggest you look at a smaller frame

19" isn't always a large - some bikes (like an Orange Crush for example) 19" would be classed as a medium. Some other brands have 17" as a medium.


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## Sharky (10 Aug 2018)

Is your old bike comfortable?

Start by taking measurements of all the relative contact points
- saddle to pedals
- saddle to handlebar grips
- height difference between grips and saddle
- fore/aft position of saddle relative to bottom bracket

Then compare with the new bike. If you can achieve the same positions on a smaller frame, then go for the smaller frame.


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## Levo-Lon (10 Aug 2018)

If it's a nut knocker it's too big.

I tend to get small 16 frame size even though sizing says medium 17-18
I find them a stretch.

But my medium commencal was a bit small ....it's all about riding and trying I'm afraid.

I've stopped bying off the net,I go to Rutland Cycles and test ride now.


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## Jody (10 Aug 2018)

Alan Farroll said:


> I have had a sit on it and when standing over the bike there is very little clearance between myself and the top tube.



Take it out for a ride and see what it feels like. My Anthem is a small (16" and i'm 5'5) and my knackers rest on the top tube if stood in the middle even though its sloping. But the bike itself is perfect in terms of riding/handling. 

The most important part is that you're not stretched out or cramped in the cockpit. Slight changes can aways be had after purchase with riser bars, stem length, spacers on the steerer etc.


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## Alan Farroll (11 Aug 2018)

Thanks everyone for your feedback. I visited another shop yesterday and sat on an 18 inch and it was just touching my groin so I think I should sway towards caution and get a 17 inch.


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## SkipdiverJohn (12 Aug 2018)

17" seems very small for an adult bike to me - I'd regard that as a child-size frame, and I'm not much bigger than the OP although my legs are a bit longer. I've got two (old-school rigid) MTB's with 23" frames and get on fine with these for general riding, although I tend to ride a 21" frame on gravel and dirt tracks in woods, for the obvious reason. Sizing seems to have got rather silly in recent years, most modern bikes I see these days look too small for the rider - like they've borrowed it from their little brother!


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## FishFright (12 Aug 2018)

[QUOTE="SkipdiverJohn, post: 5346839, member: 56288"*]17" seems very small for an adult bike to me* - I'd regard that as a child-size frame, and I'm not much bigger than the OP although my legs are a bit longer. I've got two (old-school rigid) MTB's with 23" frames and get on fine with these for general riding, although I tend to ride a 21" frame on gravel and dirt tracks in woods, for the obvious reasons. Sizing seems to have got rather silly in recent years, most modern bikes I see these days look too small for the rider - like they've borrowed it from their little brother![/QUOTE]


Not for a frame with sloping geometry


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## Blue Hills (12 Aug 2018)

SkipdiverJohn said:


> 17" seems very small for an adult bike to me - I'd regard that as a child-size frame, and I'm not much bigger than the OP although my legs are a bit longer. I've got two (old-school rigid) MTB's with 23" frames and get on fine with these for general riding, although I tend to ride a 21" frame on gravel and dirt tracks in woods, for the obvious reason. Sizing seems to have got rather silly in recent years, most modern bikes I see these days look too small for the rider - like they've borrowed it from their little brother!


As fishfright says, things are a bit more complicated with modern frames and sloping top tubes. I have bikes of several nominal sizes and all fit in terms of riding comfort and that dreaded but useful term "cockpit". I have an old faithful Ridgeback with a sloping top tube which someone on a ride told me was too small for me but in truth it has always ridden just fine. I have checked and although it has a lot seatpost shwing it is not beyond the safety limit. In size it is also I think very close to my old Dale fast city bike. That also rode wonderfully sat on it even though I must admit that sometimes when I approached it from afar, seeing it parked/lockedf, it did look curiously small.

Beyond sloping top tubes, the matter is further complicated by the fact that different companies measure bikes in different ways - from the centre of the BB to the top of the top tube, to the middle of the top tube, or to the top of the seatpost on the frame. And, dammit, I have even discovered that Ridgeback changed its system over the years. I had always thought that that old Ridgeback was a 19in. Merasured to the top of the seat tube. But I now understand that when the bike was made, mid to late 90s, they measured to the centre of the top tube where it hit the seat-tube. So in those terms I gather it is more like a 17 or 17.5 inch. I have since acquired another different Ridgeback of similar age which is 19inches to the middle of the top-tube. Also rides fine and maybe looks better/more conventional. Also sloping top tube. Both of those bikes are 700C wheels but as 90s hybrids have a certain MTB heritage.

More recently I bought a Ridgeback Expedition. 26 inch wheels. Slopinmg top tube. That believe it or not is classed as large and is said by Ridgeback to be all of 57cm. But I gather that they are measuring that to the top of the frame's seat-tube. I tried this size and the one below (maybe 54cm) and surprised the shop by going for the bigger one as they expected me with my height of 5ft8 to 5ft 9 to be a 54cm. I musty admit that I partly chose the bigger one as it sort of looked betterv as I admired it from afar across a darkened room  Although initially I feel slightly sat on top of it rather than in it compared to some of my other bikes, it rides just fine. And carries my ton of camping gear very well.


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## Oldbloke (12 Aug 2018)

Alan Farroll said:


> Hi,
> 
> I have a hard tail mountain bike but seriously considering investing in a trail/xc full suspension. A local shop has this model below at a reduced price but it is a 19inch frame which I think is a size large and not medium. I have had a sit on it and when standing over the bike there is very little clearance between myself and the top tube. I am 5’11” or 180cm tall with a 32 inch inside leg. I am concerned the bike is too big for me. Is that the case and should I look for an alternative with a size smaller in frame?
> 
> ...



I'm the same size as you; bought a Giant Fathom hardtail in size large last year as recommended by Giant dealer. Although it felt ok on test ride I found it way too big offroad, too stretched even with a short stem. Recently sold it & bought a Merida 96 XT full susser size medium, fits perfectly. My first Merida which I can highly recommend; good luck with your search!


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## screenman (12 Aug 2018)

My 29er has no standover room, in 2 years of riding mainly off road it has never been a problem.


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## Blue Hills (12 Aug 2018)

Oldbloke said:


> I'm the same size as you; bought a Giant Fathom in size large last year as recommended by Giant dealer. Although it felt ok on test ride I found it way too big offroad,



I'm not an MTB rider but from what I understand smaller is often better for serious off road stuff. If I'd been contemplating serious downhill athletics on my MTB-heritage Expedition bike (see above) I think I would have gone for a smaller frame.


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## fossyant (12 Aug 2018)

Also, when picking frame, make sure there is enough exposed seatpost to fit a dropper post should you wish to get one. They have a minimum insertion measurement. Each one is different though, but if you've not got much exposed seatpost, you won't be able to fit one.


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## Blue Hills (12 Aug 2018)

On modern bike frames, I was also encouraged that that 90s Ridgeback (and the dale) weren't all that bonkers when I saw the cover of this book.

https://www.ebay.co.uk/p/Adventure-...Stephen-Lord/89733063?iid=302493897446&chn=ps

Dig the shamefully exposed seatpost on that skipdiver 

Also worth considering, to appreciate how academic this can all be, what would the measurement be of a brommie?

Or this:













Speed pro on top



__ Blue Hills
__ 8 May 2018






I have both of those bikes.

Positively obscene amount of seatpost being flashed.

all the best


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## SkipdiverJohn (12 Aug 2018)

Blue Hills said:


> Positively obscene amount of seatpost being flashed.



That's just wrong, way too much. I don't tend to apply the same standards to shoppers/folders, but on a conventional frame I reckon anything much over 6 inches of seatpost on show looks weird and to my eyes, says the frame is undersized.


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## Denis99 (16 Aug 2018)

I'm the same height and inside leg as the orignal poster.

Had a look at the geometry page.
For me, it would be the medium. The large is just a tad too big in my opinion.

The large could work, but I find that for off road riding, the slightly smaller size is a better option.


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## gasinayr (16 Aug 2018)

Old rule of thumb for sizes was road bike, inside leg - 10" mountain bike inside leg - 12"
What no one has pointed out is that the bottom bracket on road bikes is lower than mountain bikes so standing on bike with guys and dolls touching the top tube has nothing to do with sizing
OP, measure your existing bike BB clearance from ground and compare with mountain bike, you might find to the top of seat tube on a 21" road bike might be the same as a 19" mountain bike


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## gasinayr (18 Aug 2018)

gasinayr said:


> Just checked my bikes, I have a 19" Dawes touring bike and a 17.5" Trek mountain bike, measured both from ground to top of seat tube, both the same. Measured from ground to centre of bottom brackets 1.5" of difference, the Trek is 1.5" higher off the ground than the Dawes


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## SkipdiverJohn (18 Aug 2018)

MTB frames do tend to have more BB clearance. If I compare my Raleigh MTB to my Raleigh hybrid, which are both of the same design era, the hybrid geometry has 1 1/4" more BB drop than the MTB. However you also have to consider wheel diameter (26" vs 700c in my case) and tyre width fitted as both will affect ground clearance and standover height.. It's obviously better for an MTB frame to have a marginally lower standover height than a road machine, but even so there are a lot of really silly small sized frames being ridden these days, especially on Road.


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## Blue Hills (18 Aug 2018)

I may send you a pic of one of my shameful bikes skipdiver.

You are giving me serious doubts.

PM me your email.

all the best


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## SkipdiverJohn (18 Aug 2018)

Noooo, I don't want to see that!


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## screenman (18 Aug 2018)

I like my small framed bikes, you can keep the old stuff as I have no passion for it


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