MTB Frame sizing??

[NeilM]

I'm around 6'1" with a 34" inside leg and I'm another that rides 17.5 to 19" frames. The most important thing for me is top tube length, which I like to be about 22.5 to 23".

 

[lrh]

Another 6' 1"er here!

On older 80s MTBs I find 20" equates to ~22.5" top tube (horizontal dist between head tube and seat post centres) and anything smaller feels cramped in the saddle.

But from the mid 90s 20" means more like ~23.5" top tube and that's plenty big enough. My Klein is that length and I've put a shorter stem on it for a more relaxed, upright riding style.

 

[Tazio]

I'm a recent convert to the top tube being more important than the seat tube.

My main MTB is on the limit for me size wise and some may say it is too big, however reach wise it is perfect and a very comfy ride. I can't chuck it around as much as my smaller frames but it stays comfy on a long ride and feels nicely stable. Maybe I'm getting old and my days of enjoying twitchy handling bikes are behind me.

 

[Loki]

Standover height is key as it's the one thing you can't change.
A 17" frame with a high BB will give a height that will be too high for some. Baz77's MTrax 350 is a good example of this it's a 17" frame C-C but as it has a high BB comes up like a 19" in standover height and is just too big for me as I need an 18" size with most other makers. A seatpost can be changed from layback to inline and vice versa to change saddle to bar reach and so can the stem but you are stuck with 26" wheels and toptube/BB height.
The M-Trax is more the exception than the rule as you'd usually need a 19" like others have said but it's worth actually getting on the thing just to be sure.

Carl.

Using seatpost setback and stem with specs that differ from intended design of the builder will change the ride/balance of the bike and IMO is NOT the way to make a frame fit.

 

[drcarlos]

Standover height is key as it's the one thing you can't change.
A 17" frame with a high BB will give a height that will be too high for some. Baz77's MTrax 350 is a good example of this it's a 17" frame C-C but as it has a high BB comes up like a 19" in standover height and is just too big for me as I need an 18" size with most other makers. A seatpost can be changed from layback to inline and vice versa to change saddle to bar reach and so can the stem but you are stuck with 26" wheels and toptube/BB height.
The M-Trax is more the exception than the rule as you'd usually need a 19" like others have said but it's worth actually getting on the thing just to be sure.

Carl.

Using seatpost setback and stem with specs that differ from intended design of the builder will change the ride/balance of the bike and IMO is NOT the way to make a frame fit.

Were not talking massive amount 10mm here or 20mm there that will do very little to alter the balance of the bike but can make a lot of difference in comfort and made a lot of difference when I felt a bit cramped and sit up and beg on my modern Kula, an upgrade in size to a 19" would have seen some painful nut/toptube interfaces.

Carl.

 

[Anthony]

Were not talking massive amount 10mm here or 20mm there that will do very little to alter the balance of the bike but can make a lot of difference in comfort and made a lot of difference when I felt a bit cramped and sit up and beg on my modern Kula, an upgrade in size to a 19" would have seen some painful nut/toptube interfaces.

Even so, Loki is right. Increasing stem length by 2cm will make a big difference (negative) to the handling of a bike and is not a good way to go.

Some people with short legs relative to their height can find that with some makes the standover is too high and yet the top tube is too short. Such people often turn to Kona/similar as a solution to that. If you find that even Konas have too high a standover relative to top tube length, maybe you ought to try another make rather than using a long stem.

 

[drcarlos]

Were not talking massive amount 10mm here or 20mm there that will do very little to alter the balance of the bike but can make a lot of difference in comfort and made a lot of difference when I felt a bit cramped and sit up and beg on my modern Kula, an upgrade in size to a 19" would have seen some painful nut/toptube interfaces.

Even so, Loki is right. Increasing stem length by 2cm will make a big difference (negative) to the handling of a bike and is not a good way to go.

Some people with short legs relative to their height can find that with some makes the standover is too high and yet the top tube is too short. Such people often turn to Kona/similar as a solution to that. If you find that even Konas have too high a standover relative to top tube length, maybe you ought to try another make rather than using a long stem.

So you have 2008 Kula as well then?

Carl.

 

[Takingabreak]

20"