Kona sizes / sizing - early 90's

TreaderSteve

Senior Retro Guru
Just a quick one please - 1991 Konas - how are they measured? Centre to top is something I think I've read but can't remember on which thread I saw it.
My Explosif is 20" centre to top - does that make it a 20" and the biggest as per the '91 catalogue?!
 
I believe this is correct , centre of bb axle to top of seat tube. certainly how I have measured them and I still have three! Could never find 20" to suit my 6'2 lump so I have longer posts and now I'm 40 plus yrs old a shorter stem and higher rise bars!
 
Actually, in 1991 it was the length of the seatube itself.
So top of BB shell to top of seat tube, they used this method up to an including 1992.
So in 1993 they moved the the normal centre of BB (I.e from the crank axle) to top of seat tube.

I put a few here for me if I need to remember and of course others to look at.
https://www.retrobike.co.uk/wiki/MTB_Frame_Measurement
Didn’t know about the difference in measurement method on the earlier ones, but would make sense as I struggled to work out if an ‘92 Cindercone I had, was a 19“ or 20” As the CTT measurement was neither 19” or 20”.

As curiosity now triggered, will shuffle off to the garage later to measure my current 18” Konas - ’91, ‘94 & ‘98s.
 
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How interesting, thanks Fluffychicken. I wasn't convinced mine was the largest - I thought the occasional headtube in photos was maybe longer than mine but it's difficult to tell. I guess it's a 19" but similarly off to the shed I go!
 
Scores from the garage are in:

TBTT = Top of BB shell to top of seat tube
TBTC = Top of BB shell to centre of seat clamp

’91 Fire Mountain - CTT 19”, CTC 16”, TBTT 18.5”, TBTC 18”
’94 Explosif - CTT 18”, CTC 15”, TBTT/TBTC 17”
’98 Kilauea - CTT 18”, CTC 15”, TBTT/TBTC 17”
’98 Ku - CTT 18”, CTC 15”, TBTT/TBTC 17”
 
My '91 Explosif measures 19 3/8" from the top of the BB shell to top of the seat tube. I measured on the side of the bike - if I ran a tape measure down the back of the seat tube it'd be a tad longer.

Your '91 is TBTT 18.5” BerthaPog....neither 18.5" or 19 3/8" are quoted catalogue sizes....none the truly wiser! Going by the geometry for the various sizes in the catalogue I guess I'll have to wait til it's rebuilt with forks on before I could try to measure the wheelbase.
 
My '91 Explosif measures 19 3/8" from the top of the BB shell to top of the seat tube. I measured on the side of the bike - if I ran a tape measure down the back of the seat tube it'd be a tad longer.

Your '91 is TBTT 18.5” BerthaPog....neither 18.5" or 19 3/8" are quoted catalogue sizes....none the truly wiser! Going by the geometry for the various sizes in the catalogue I guess I'll have to wait til it's rebuilt with forks on before I could try to measure the wheelbase.

Measured the Fire Mountain hub to hub which came out as 42 and a bit inches. So it’s an 18” based on the catalogue measurements.
 
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