Conflicting advise on frame sizes.

[Sam_Fischer]

Hey guys. I did some rudamentry searching before posting, though didn't find anything really relevant. So sorry if this is a duplicate thread.

I'm not too knowledgeable when it comes to bikes, I've been riding for a large part of my life but I've never actually bothered to learn too much. Basically I've been riding generic stock bikes, when they break, I get new ones.

Anyway, I'm currently trying to get some solid advise regarding frame sizes. In the past, people I've asked, have quoted me a bunch of different acronyms and corresponding sizes to go with those acronyms, and others have used length based systems, and others still a small-reg-large system. Basically I've been getting advise from people who don't know themselves.

So really, my question is. What size frame should a person of around 185cm / 6 foot 1, be riding? I do acknowledge that different manufacturers may use different systems, but length wise, what should I be shopping for?

Cheers.

 

[Daneel]

The best way to get the proper fit is to go into a bike store and get measured up. Most decently large stores will happily do this for you.

 

[Simsoi]

Any frame in large should do the trick.

Most manufacturers have sizing guides online in any case

 

[Damienp]

That's mostly true. However there are lots of different factors that come into play. I know of a few 6' + guys that are on medium frames. Not many but there are certainly cases.

Get a fit done or head over to competitivecyclist[dot]com and check out their fit calculator.

You put all the measurements in and it will punch out several options for mountain bikes depending on what you ride and how you like to ride. Use the outputs as a guide when checking out bikes and frame geometry on the internet.

Round up a shortlist of contenders then hit the shops for a few test rides or see if there is a demo bike you can grab for a day or so and really get the feel of it.

Remember stem sizes, bars and saddles can all be swapped out and adjusted to items of your suiting and should happen as part of your fit by the shop that you buy from. If it costs extra see if you can negotiate that cost down but most shops do a fit for free when buying a new bike.

 

[Sam_Fischer]

Thanks heaps for the advise guys. Mucho appreciado.

//

And just when I think I've got a grasp on frame sizes I discover there is a huge difference between mountain bike frames and bmx frames. Well played bicycle frames, well played.

 

[flamin'trek]

I'm around 181cm and have a large GT and medium Yeti in my garage at the moment. I've ridden medium Trek and 19" Kona. They all fitted pretty well. In finding a frame recently I compared frame sizes on the internet and found that different manufacturers make different sizes with different names, pain in the bum.

The only way to check them out was to look at the frame geometry and stuff like top tube length, seat tube length (size?) without trying them on.

Dont forget that one mans 6' is different to anothers so your mates correct size might not be yours. I used to ride with a buddy the same height as me, but could never ride his bike without adjusting the seat down. I've got short legs and he didn't apparently

 

[driftking]

As you have probably already worked out you will be in the large end of the scale.
However as others have pointed out there are other factors.
Each manufacturer will have different recommendations for their bikes.Some bikes come in 4 sizes, some only 2 and then Geometry will varry with each which adds another factor into the equation, then of course each person is different.This is why there is no exact answer when sizing up a bike before you get fitted.
Once you figure out what bike you want then you will be able to find the correct size, have a look at what the manufacturer website recommends and then get fitted by your LBS, once this has been done go with what you feel comfortable on and if you find you are in the middle of sizes go with which ever you prefer.

 

[harmonix1234]

It depends on so much.
Different bike styles will have different systems.
Road bikes are measured in Centimeters, mountain bikes in inches.

But then you have different mountain bike manufacturers will have different measurements for the same size. ie A Brand 'X' 19" bike frame will have a 595mm top tube where as brand 'Z' 19" frame will have a 580mm top tube.

Geometry, and frame sizing is so dynamic that you have to use the frame size - human height scale only as a very basic guide.

I myself am exactly 6 feet, 85 kilos.
When I went and got fitted at a bike shop I was told I need a 21.5" frame.
The next shop told me I needed a 20" frame.
The third shop said that I could go down to an 18" frame.

A lot of room for error there.
As it turns out, I should be riding a 20" frame. But, I like the bike a little bit flickable, and I like the feeling of sitting on the bike rather than in the bike, so against all the shops advice I got a 19" frame, with a slightly longer stem and a layback seatpost.
This way it gives me the geometry I want for MY STYLE OF RIDING.

It's all well and good to say "This guy is 6.1", give him a 20" frame", but it's all about your style, and what you want your bike to feel like, and how you want it to perform for you. You may have a long body and short legs, or short arms and long legs, or a short body and long legs.

And keep in mind, changing your stem and cockpit setup dramatically will never compensate for the wrong sized frame.

If I were you, I'd test ride a 20" to start. Then try a 19" and/or 21" and go from there.
You will know what feels right and what dosn't when you take it for a spin around the block.

What style of riding do you want to do? Cross country? All Mountain? Hard tail or dual suspension? What kind of terrain? Jumps and berms, or smooth flat cross country, harsh rock gardens and fast rutted terrain? All of the above?!

If you can refine your riding goals and style it helps a lot with a question like this.

 

[Ivan]

I'm surprised that seattube length is still used to describe frame size.

IMO, toptube length is the most important measurement.

Your ideal frame size will depend on the relative length of your torso and legs, and what style of riding you plan on doing.

 

[Sam_Fischer]

So much fantastic advise in this thread. I'd love to quote each of you personally to indicate I read your advise, but hopefully my kudo's is enough.

As you've all said, body type is important. I run a fair bit since I have a runners body (long legs) so that is definitely a factor. My exact measurements are ~187CM and 80KG, so pretty average.

Also, as you've all probably concluded, I am quite the novice. I'm not looking to really go hardcore, all out, basically I'm eyeing off something in the street category. Something nice and start-er-outy (it's a word I swear) like an NS Bitch or low end Giant STP. Basically just something I can ride short/medium journeys on, but still thrash around a bit and try to land awesome 3CM jumps.

I think a 20" frame is what I'll be looking at, but obviously I'll need to get that verified by checking how it feels first (and how it feels on a larger/smaller frame).

Pew pew.