1990 Kona Explosif Seat Tube / mech Size help needed

[Singletrack74]

Hmm, thought I had this covered knowldege-wise, but I am confusing myself!

I thought the seat tube would be a 28.6, but looking at it (in the absence of calipers) it looks more like 31.8?

Can anyone confirm?

It's 100% a '90 by the way - still has the original black splatter paint, brake noodle, concept tubing etc...

I have sepnt the last hour searching here and elsewhere but can't find an answer!!

Whislt I am on the subject, bottom bracket is 68mm, but the original axle has been swapped out for a 122.5. Would the original Suntour have been a 125?

 

[hamster]

28.6 seat tube I'm sure.

Not sure what chainset you have, but remember the difference between a 125 and 122.5 is less than 2mm on the drive side, which is frankly the same as how worn the tapers are. You won't notice a difference in the real world.

 

[Singletrack74]

Re:

It really, really doesn't look 28.6 - I have measured both the mech and teh seat tube as carefully as I can and they both seem bigger...

I know teh Cindercones etc had 28.6, but my thought is that the Concept tubing may give a different outer diameter to the tubing on other models from that year...

Taper internally on the XC Comp crank is excellent - it still has the original rings, with little wear, so probably very few miles on it!

 

[al-onestare]

Re:

28.6mm

Any larger is for aluminium frames.

 

[FluffyChicken]

Re:

Yep 28.6mm (you are measuring the right part and not the ovalised part)
Seatpost should be 26.8
Headset 1"

Unless it's moving into the 1991 era and the seatpost may move up to 27.0 or may not, but headset will be 1-1/8".

Still same front mech.

 

[Singletrack74]

I’m literally measuring the clean paint where I’ve removed the front mech

 

[Singletrack74]

Re:

So, I am still convincing myself that it looks bigger than 28.6 - so I have ordered a digital Vernier caliper on Prime, so will confirm it tomorrow!

 

[mk one]

Hi, the front mech is 28.6 and the seatpost is 27.0 !!

based on my '90 Explosif sat in front of me

Mark

 

[Singletrack74]

Re:

Well, I needed an excuse to buy new tools anyway :facepalm:

 

[mk one]

Cant have enought tools