Fit - inseam vs height
Girona
Posts: 13
When choosing a new MTB, I've become aware of how important it is to choose the correct frame size. I think my last bike was not a perfect fit, and I hope to get a better size this time.
Now, first of all, I know you have to actually try the bikes you're interested in. And I intend to do just that. But when browsing for bikes online, I like to look at the geometry charts, and make a list of bikes and sizes I would like to try. My question is with sizing: is the inseam measurement more important than height, or the other way around?
I have tried different formulas and calculators, and looked at some charts. Those that focus on height put me in the 21'-23' (22' average) area. Those that are based on inseam (and other measurements) recommend a 19'-'20 frame. So there's a 3 inch difference (19' vs 22'), depending on if I use inseam or height as the primary measurement.
I'm 6''2' tall, and my inseam is 34.2'. Would you recommend going towards a smaller (19') or larger (22') frame size?
Now, first of all, I know you have to actually try the bikes you're interested in. And I intend to do just that. But when browsing for bikes online, I like to look at the geometry charts, and make a list of bikes and sizes I would like to try. My question is with sizing: is the inseam measurement more important than height, or the other way around?
I have tried different formulas and calculators, and looked at some charts. Those that focus on height put me in the 21'-23' (22' average) area. Those that are based on inseam (and other measurements) recommend a 19'-'20 frame. So there's a 3 inch difference (19' vs 22'), depending on if I use inseam or height as the primary measurement.
I'm 6''2' tall, and my inseam is 34.2'. Would you recommend going towards a smaller (19') or larger (22') frame size?
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I'd say reach and effective top tube are more important than stand over.0
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Girona wrote:My question is with sizing: is the inseam measurement more important than height, or the other way around?
might be an interesting read for you
viewtopic.php?f=10002&t=12692834
but at yout height i guess you will not have stand over issues."Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
Parktools :?:SheldonBrown0 -
Standover is usually not an issue. It's more a question of overall fit, and whether my inseam or height should be the deciding measurement for the frame size.0
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Neither should be used... Our 18.5" Aeris is longer than most 21" bikes... so sizing by the seat tube is pretty much irrelevant Im afraid. Simple way to look at it is to find out the effective top tube of your old bike, and base your new one on that.
To measure the ETT measure a horizontal line from your seat post to the middle of the head tube (fork steerer). This will give you a good comparison for the size of your bike to what you are looking at. Most manufacturers will publish their ETTs.A Flock of Birds
+ some other bikes.0 -
My old bike is a size 22' on this chart. I've always felt a little stretched out on it, and think I should go for a smaller size for my next bike. The question is if I should go all the way down to a 19' this time.
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No Effective top tube on that chart (unless that is AH, but without the drawing who knows), the tape measure is your friend.
Bear in mind you can use offset or inline seatpost, so add that in to the measurements if it is offset, but it also allows you to tweak the cockpit length, so if the new bike comes with an inline, you could fit an offset to lengthen it by 20mm or vice versa, 20mm being not far off the change in ETT you'll get from going a size up or down.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
(Yes, AH is effective top tube in that chart.)
So, let's say I was looking for a bike, but had no idea which size to look at. If I needed a starting point, should I look at my overall height compared to the effective top tube length? If so, which ratio should I use? Or are there better ways to get into the right ballpark of frame sizes?0 -
Find a bike you are comfortable on and measure it!
ETT is the key dimension, and it's most closely related to torso length (look at a side on picture of someone on a bike, the biggest part of the length is the forward lean of the torso, the lesser part the reach of the arms) as can be seen here https://drscdn.500px.org/photo/6278132/ ... 9195fa494a (any excuse right) arm length has a close correlation to leg length, so start with your height and then go up a size for shorter legs or down for longer (which is contrary to how most people look at it as longer legs=longer seat tube).Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
I am amazed no one has said go and sit on some bikes to work this out. You cant look at size charts and try and work it out if you have limited experience and knowledge of bike geometry and the impact changes to effective top tube and angles make to your ride.
Even if you arent interested in buying the bikes you go and look at by trying a few out you will get some reference as to what sizing works better for you.Closet jockey wheel pimp whore.0 -
paul.skibum wrote:I am amazed no one has said go and sit on some bikes to work this out. .
I'm amazed you didn't read the post above yours!The Rookie wrote:Find a bike you are comfortable on and measure it!Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
The Rookie wrote:paul.skibum wrote:I am amazed no one has said go and sit on some bikes to work this out. .
I'm amazed you didn't read the post above yours!The Rookie wrote:Find a bike you are comfortable on and measure it!
I was hoping you would read my very first post in this thread:Girona wrote:Now, first of all, I know you have to actually try the bikes you're interested in. And I intend to do just that.0 -
Go try the bikes I'm afraid.
For instance I'm also about 6'2" with a 34" inside leg, and I ride a medium Mondraker with a 30mm stem(instead of the 10mm). if I'd gone by size chart I'd have been on the large and testing both back to back in various config I know I made the right choice. on a mtb the reach is probably the more important factor!0 -
The Rookie wrote:paul.skibum wrote:I am amazed no one has said go and sit on some bikes to work this out. .
I'm amazed you didn't read the post above yours!The Rookie wrote:Find a bike you are comfortable on and measure it!
You could have highlighted it in bold and sent me a memo. I am far to important to read other peoples posts.Girona wrote:I was hoping you would read my very first post in this thread:Girona wrote:Now, first of all, I know you have to actually try the bikes you're interested in. And I intend to do just that.
My start point would be try a bike in my lbs to gauge the size then go look online for other bikes that have similar geometry - you are coming at it arse about face. IMHO. But also I refer you to my reply to Rookie above.
Closet jockey wheel pimp whore.0 -
Sorry, I'll try harder next time!paul.skibum wrote:You could have highlighted it in bold and sent me a memo. I am far to important to read other peoples posts.Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.0 -
Best to try a few bikes to see what fits and feels best. You can then check geometry charts to find similar bikes. Being tall at 6ft7 i have to make sure bikes are close to my current bikes geometry as some manufacturers larger frames are too small.
In answer to your question inseam and your bodies proportions matter. I have a relatively long body so can fit on more bikes than if i had longer legs.0
