Want to know what SIZE bike to get? READ THIS.

Mickey Eye

supersonic wrote:

As it says in the first post, you can't really equate one model or brand with another.
So unless you understand all the numbers then it is a case of trying it out.

Is there a guide to "the numbers" anywhere? Obviously it will never replace trying out a bike but it might prevent people from jumping in completely blind.

supersonic

"Can anyone tell me why GT use s, m, l, xl, xs sizing. Is this just another way of confusing people ? I guess it has little consequence if you are actually going to test them, the proof is in the riding not the size naming convention I suppose."

It is just to differentiate one size from another.

"Is there a guide to "the numbers" anywhere? Obviously it will never replace trying out a bike but it might prevent people from jumping in completely blind."

Main measurements are standover height, seat tube length, top tube length (and effective length), head angle, seat angle, chainstay length, head tube length and bottom bracket height. Changing one may alter another. Best bet is to google the terms to see what they mean and how they interact

But as above, trying them out, getting a feel and comparing to others is a great way of dsciding what feels best. Try a couple of sizes of the same model. If it has travel adjust forks, al;ter them - does it feel different? More travel slackens the head angle which steadies the steering making the bike more stable. It will also raise the BB a little.

Only after a lot of riding and comparing will you find the numbers that you like, and even then the ride may feel different!

UK2004

Would appreciate some advice, just received my bike is a 17 inch frame, I am 5ft 9 with shortish legs, was avised by company to get a 17 frame when standing over the toptube there is no gap I can just about squeeze a finger between toptube and body adn with seat in lowest position will need to hae tip toes to touch floor, it just seems too big, I an cut the seatpost but am not sure if the size was correct that I should be having to do that, does it sound as if really I need the size 15 frame?

supersonic

The frame you have for that model is too big.

UK2004

Turned out ok int he end have been riding it and has been ok think I needed to get used to it after having a trials set up when I last rode a few years ago!

propaganda

When I look at the manufacturers recommendations (Specialized Stumpjumper) I should be going for a 17" - unfortunately that size has sold out - so the dealer is getting an 18" to try. I am a bit sceptical as I am 5'8" with a 30" inside leg. What should I be looking for when the bike arrives - standover, reach etc?

supersonic

Both. Make sure you have good clearance with standover, then see wht the reach feels like.

[Deleted User]

The user and all related content has been deleted.

supersonic

As in thew original post, one 20" bike is not the same as another - can be markedly different! Forget the numbers, try them out and go on what feels best.

Also seat height is based on extension to pedals, rather than the floor.

dickst3

Reading another thread on what size frame to buy depending on height/inside leg got me thinking, how do you measure inside leg? Presumably its floor to right up tight as high as you can go? Not the same as trouser fitting!!

Rich

Anonymous

propaganda wrote:

When I look at the manufacturers recommendations (Specialized Stumpjumper) I should be going for a 17" - unfortunately that size has sold out - so the dealer is getting an 18" to try. I am a bit sceptical as I am 5'8" with a 30" inside leg. What should I be looking for when the bike arrives - standover, reach etc?

Well, I'm 5'7" and a 30.5" inside leg. On my 18" GT (smallest they do for the i-Drive XCR 5) I clear the tube on standover by maybe an inch or two with feet flat. Doesn't seem to be an issue. Sat on it, saddle doesn't need to go right to the bottom. Only concern is some places say my leg on the peddle set at the bottom should be straight, but it's marginally bent. If I raise the seat to get the leg straight, I'm barely tip-toe.

But then I've been out on it set the way I feel comfortable and it feels great, and I can dismount with no struggle.

Some sites say 30/31" inside leg - 18". Others, and in particular a lot of user experiences seem to suggest that kind of inside leg and especially around my height, they're often using 16" frames.

The manual I got says I should not touch the top bar on the standover test even if bouncing up and down on heels, but I do a little. But then my bike looks nothing like the generic diagram and has a more inclined top bar.

In short, some things say the frame's too big, others say about okay. Key thing is it feels okay to me, but I've yet to use it in real anger. It is bigger than my old bike however, but that was definitely too small (in reach mostly).

So yeah, it all depends.

spark1479

Only way to find the right size is to do a test ride. i've just recently bought a new FS bike and must have test rode 10 or so different bikes. Of the ones I felt comfortable on, there was at least 3" difference between manufacturers stated sizes.

I bought a Orange 5 frame after trying out an already built bike in my LBS.

cps26

I’m currently having a bit of a sizing dilemma, though I’m hoping it will be resolved with the next bike I try…

I’m 5’11” with a 33 inside leg; coming fairly new to MTB though used to ride a bit when I was younger. I was initially keen on the Scott Scale 60 – I tried it in a large first, and it felt a bit too stretched out – perhaps rightly, as it is an all out XC race bike. But then I tried the medium, and I felt (I think) slightly scrunched up. So I wonder whether because the Scale is meant to be a race bike, the large would be the ‘right’ size, but if I’m not going to be racing it, is likely to be a bit uncomfortable?

I’ve now tried a Cannondale F3 in large, which I think feels about right (though having ridden so many different bikes this weekend, I’ve got a bit confused!) and I’m going to try a Cannondale F4Z in large this weekend, which I think has the same frame but a slightly shorter stem than the F3, and might perfect.

Anyone here about my size and ride a Cannondale F series with the Caffeine frame? If so am I looking at the right size?!

enzofan

I have recently purchased the Decathlon Rockrider 5.3. I was advised initialy by an advisor on the phone to go for a a large (21") I am 6ft tall inside leg around 32/33. However when I got to the store they only had a large in stock which I was told was a 19". However the front handle bars are lower than my old 18" bike and I am wondering whether the sales people just want you to buy whatever is available in the store,so you have to be careful.

The bike fit is not too bad although I am leaning forward due the bars being so low. Do you think the frame is too small?

blister pus

Not necessarily. Adjust the stem spacers to raise the handlerbar and see how it feels.

And try to keep it on the other thread, enzofan.

enzofan

I have measured the clearence while I stand and its 4" on bike. The total length of the top tube /bar is 20" on the bike. Is that sufficient considering I am 6ft and have around 32/33" inner leg?

blister pus

1) All frames and frame sizes are different. And even frame sizes from the same manufacturers range can differ.

2) Depends where you are measuring to and from. Top tube length is from the centre of the seat post hole to the centre of the stem hole.

I'm 6ft with a 33" leg and my top tube length is 22" and I went for a large Giant Boulder Trail. I have the right amount of room for me other people will be different - which is why you are supposed to get fitted properly and see what suits you. The salesman was lazy and poor.

3) Raise the height of the handlebars using the stem spacers - I gave you a link in the other thread showing you exactly what to do - it should also be in the manual.

Here it is again: http://www.trails.com/video_257_adjust- ... -bike.html

4) See how that feels. If it still feels wrong then you can either adjust the seat back by a centimetre or so, assuming you can.

5) If that isn't right then you need to contact Decathlon to organise a demo of the next size up.

dickst3

That link was useful thanks.

Anyone considering a Genesis Core 20 wondering what size to get, the height of the top tube (from the ground) on the 19" frame where your nuts would be is around 30.5". Therefore you will want a minimum 31-32" inside leg (depending on how you measure) and if you want to do spirited riding you'll probably want the 17.5" frame.

Rich

PinkSpider

Cheers for the info! Going to measure my inner leg again. I think standover is most important really as I stand up most of the time (and will be apart from on long distances) and I'm used to riding smaller bmx/ bmx 24" bikes.

The Spiderman

hughesb wrote:

Hi

Im looking at buying a 'Giant' Mountain bike off the internet. However I am unsure what the sizes of the frame are as they are in S,M and L. Could anyone tell me what inch frame these sizes would be?

Thanks

S 16",M 18",L20"

Read all of the above and try one first though!

peterw47

5'2" 29" inside leg - do I go for the 16" Cube LTD Race from CRC or wait and try a 13"/15" Specialized (bearing in mind some of the figures are shorter on the 16" Cube than the 15" Specialized!!!)

bobpzero

projectsome wrote:

LordBanks wrote:

What about if you just want to buy a frame??

How do you test ride one on those???

hmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm??????????????/ :twisted:

hold it between your legs like one of those wooden mop horses and gallop around the store.

doesnt help me. im doing a mtb xc build for road usage and im not an experienced cyclist (as in d.i.y. bikes a lot) this is too confusing tho not enough for me quit the bike build. seeing my quite close to crc. should i just speak to them?

supersonic

If building up a frame you should have an idea of what geometry you like ie reach, angles etc.

bobpzero

for the road bike its 56.5cm horizontal top tube length so i thought for the mtb xc frame at 55.4cm horizontal top tube length would be best because it would prove to be more comfortable being less stretched out.

supersonic

MTBs are often much higher at the front though, so your weight is tipped back somewhat.

Also longer wheelbases and slacker head angles are the norm.

wicked2627

Hi,

Just joined the forum. Used to have an M2 Stumpjumper back in 1998 which I sold a few years later.

Work have just started the Cycle 2 Work scheme so I thought 'Why not'. I am only limited to Halfords so have done some research and have just put my deposit down on a Boardman HT Ltd Edition.
http://www.boardmanbikes.com/mtbht/ht_LTD.html

I hope others rate this bike - the equipment looks good but guess i'll need to get used to it all (I have V brakes on my spec!)

From reading this topic, I realise I should have tried the bike for size but I ordered a small as it is advertised as 16inch. The reason being, my Spec was 15 inch as I thought the smaller the better and they didn't have any for me to try (as not yet released). I'm 5ft 4 and the spec from the website is

Geometry
Top Tube effective (cm) Seat Tube (cm) Head Tube (cm)

Small 56.5 40.6 10
Medium 59 45.7 11.5
Large 61.5 50.8 13

There does not seem to be much in it - how important is it that I should go back and ask to try out a small Boardman for size? I thought the seat can the raised and the seat moved back and forth for ensure a correct fit?

I apologise in advance for all the questions I may ask going forward!

supersonic

It can yes - but you can't do much to change the top length.

Dubzy

Invaluable information on this forum. Went to buy a Rockhopper 17 frame and found my vitals resting left and right on the top tube. I'm obviously more of a short arse than I thought. Will have to consider smaller frame or different geometry. Test before buying should be mantra!

Dubzy

supersonic

It can be suprising just how much a listed size varies bike to bike!

jaybo1973

I have been away from biking for over a year and just got back into it. I have always had concerns that my frame is to big. I am 6'1, 33" inside leg. I have a 20" 2007 kona cindercone. It feels ok to ride but the stand over concerns be due to the angle of the frame towards the forks. directly between my legs is ok when I stand over the frame. but if you were to fall forwards or if your foot went down a hole? I would imagine the next frame size down would be the same though? as it has the same forks.