
mtbr member
Reputation:
Is the 21" a must for a 6'4" / 210lb guy
I am 6'4" and 210 lbs with a 36" inseam. Is the 21 a must or can I consider the 19?
Looking at the HiFi.

mtbr member
Reputation:
im 6' and ride a 19 and feel cramped but you need to try it for your self

Fat guy on a bike
Reputation:
I would say yes, especially on the genesis geometry. I'm 6'3" and i was not so hot about climbing on a 19" hiFi demo bike.

willtsmith_nwi
Reputation:
You could ride a 17" if you like. That says nothing about whether that is optimal.
Optimally, you should ride at least a 21". A 23" may be in order if you're the "long torsoed" rather then the "long legged" type.
Last edited by willtsmith_nwi; 10222007 at 05:09 AM.

Master of None
Reputation:
I have a 34" inseam and I ride a 18" (seat tube) hardtail and a 18.25" fully all mountain bike. I like smaller bikes, they are more comfortable for me, and I can drop the seat more on the tricky stuff.

mtbr member
Reputation:
Thanks to all for the replies. I went back to the LBS today and rode the 19". It did feel a bit cramped. I will wait on the 21".

I'm 6'3" with 34" inseam and stick with a 24 to 24.5 ETT length, puts me squarely into most Larges.
Happiness depends more on the inward disposition of mind than on outward circumstances. Benjamin Franklin

mtbr member
Reputation:
im with greenlightgo.
always rode 19 inch frames myself and theres usually an inch or 2 spare left on the seatpost.
i rode a 21 inch frame once and its not an experience i would like to go through again.

mtbr member
Reputation:
Originally Posted by konut
im with greenlightgo.
always rode 19 inch frames myself and theres usually an inch or 2 spare left on the seatpost.
i rode a 21 inch frame once and its not an experience i would like to go through again.
konut,
Why is that? Did you feel too streched out?

mtbr member
Reputation:
stretched out and just way to high,my current bike is 24.1 inch toptube with 50mm stem and feels great.
although if i were on a all mountain rig xc setup maybe go for 70mm setup.

President, CEO of Earth
Reputation:
I think I am about the same size as you, IBThePMan, and I can not ride a 19"  I can not get proper leg extension with a normal seatpost. Even with a 400mm post there is very little post left in the frame for support. I have broken the top off several frames by running the seatpost too close to the max height  luckily all warrantied. I have seen others do this where the company did not warranty it.
I worked it out using the pythagorean theorem (with seatpost + seat tube + crankarm being hypotenuse, and leg and foot as the other two sides) and a 36" inseam with an 8" foot (ankle bone to ball of foot) requires approx. 36.9" of hypotenuse. Minus 175mm for the crank and you still need 30", minus 19" for seattube and you still need 11" of seatpost (279mm). Also, you only have 300mm of seatpost you can extend on a 350mm post, so you are left with a 21mm (about 3/4") of safety margin.
400mm and 410mm posts are available, but I have ridden a lot of bikes and I am conviced that most 6'4" people should be riding XL size bikes in most cases. If size L bikes are designed to fit us, then who are the XL bikes for?
That being said, everybody has their own preferences and you need to go with what feels right to you.
(edited to spell "Pythagorean" properly)
"Newfoundland dogs are good to save children from drowning, but you must have a pond of water handy"  Josh Billings

willtsmith_nwi
Reputation:
Originally Posted by TobyNobody
I worked it out using the pythagorean theorem (with seatpost + seat tube + crankarm being hypotenuse, and leg and foot as the other two sides) and a 36" inseam with an 8" foot (ankle bone to ball of foot) requires approx. 36.9" of hypotenuse.
The Pythagorean Theorem only works if you have a 90° angle opposite the hypotenuse. Furthermore, to apply the theorem would be difficult as you would need exactly either an exact 90° angle between the seat tube and the top tube or between the seat tube and chainstays.
All that being said, unless this guy a freaskishly long inseam and short arms, he should be on an XL (at least). If he has a freakishly long torso, he should probably be on an XXL.

President, CEO of Earth
Reputation:
Originally Posted by willtsmith_nwi
The Pythagorean Theorem only works if you have a 90° angle opposite the hypotenuse. Furthermore, to apply the theorem would be difficult as you would need exactly either an exact 90° angle between the seat tube and the top tube or between the seat tube and chainstays.
All that being said, unless this guy a freaskishly long inseam and short arms, he should be on an XL (at least). If he has a freakishly long torso, he should probably be on an XXL.
I was using the angle between leg and foot (ankle angle) to be 90 degrees and the hypotenuse the full distance from the crotch (saddle) to the bottom of the foot (pedal).
Of course I was making some assumptions about ankle angle while pedaling, and distance from top of seatpost to top of saddle (and soft tissue compression aganist the saddle) but it was the best I could do using the MS Windows calculator and MS Paint for geometry diagrams. If I had FitKit loaded onto my computer it would have been more precise, but the numbers I got seemed to jibe with my intuition and my own experience with 21" frames and a 36" inseam.
"Newfoundland dogs are good to save children from drowning, but you must have a pond of water handy"  Josh Billings

mtbr member
Reputation:
Originally Posted by willtsmith_nwi
The Pythagorean Theorem only works if you have a 90° angle opposite the hypotenuse. Furthermore, to apply the theorem would be difficult as you would need exactly either an exact 90° angle between the seat tube and the top tube or between the seat tube and chainstays.
All that being said, unless this guy a freaskishly long inseam and short arms, he should be on an XL (at least). If he has a freakishly long torso, he should probably be on an XXL.
Nothing freakish (at least I hope not). 36" inseam and long arms. I have been ridding a Trek 4200 19.5" since January. I managed to make every adjustment possible to get the right feeling in the saddle. I went back last week and they had a 21" frame in so I gave it a test ride. The feel was perfect. I ordered it (supposed to be in tomorrow).
Thanks to everyone for the input. I know that it must get old with all of us new guys asking the same dumb questions over and over, but you long time riders are a great source of information. I am now an officially hooked and this is my first "nice" bike.

willtsmith_nwi
Reputation:
Originally Posted by TobyNobody
but it was the best I could do using the MS Windows calculator and MS Paint for geometry diagrams.
Regardless of it's sophistication, you're picture may be worth a thousand words in this instance.

President, CEO of Earth
Reputation:
Originally Posted by willtsmith_nwi
Regardless of it's sophistication, you're picture may be worth a thousand words in this instance.
Ha ha ha! So you think...
"Newfoundland dogs are good to save children from drowning, but you must have a pond of water handy"  Josh Billings

for a pedaling bike go bigger....for a DH bike go down a size....at 6 foot I rode a 20 inch and loved that for pedaling
the trick is ENJOYING YOUR LIFE EACH DAY, don't waste them away wishing for better days
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