Inbetween Sizes

saiklist

Hi All,

I wouldn't normally do this but I've seen a bike online for a good price and I want to buy it without trying it!

New bike in question - Kona Lanai 2017 - Old bike - Specialized Hard Rock Sport Disc 2006

I've come to the conclusion that I am smack bang in the middle of sizes!

TL;DR;

The question is...

If I want to keep my over all Top Tube Length + Stem Length at my current 685mm do I:
A) Get the larger bike and use a shorter 60mm stem
Get the shorter bike and use a longer 80mm stem

I plan to use the bike for commuting every day (3 miles off road, 2 on), leisurely jaunts on the weekend with the other half and my new favourite activity - bike packing...

The rest of the info, if you really care!

After hours of reading the manufacturers recommendation, retailers recommendations, comparing geometry against my current bike (mainly effective top tube length (615mm current bike) and TT length + stem length (685mm current bike))

Geometry wise (the bits that matter)
1. Effective Top Tube Length - Current (615) - Medium (599) - Large (626)
2. Seat Tube Angle - Current (73) - Medium (74) - Large (74)
3. Head Tube Angle - Current (70) - Medium (68.5) - Large (68.5)
4. Standover Height - Current (789) - Medium (730) - Large (765)
5. Seat Tube Length - Current (483) - Medium (420) - Large (470)

Now you see, seat tube and head tube angles - no difference betweent he two sizes so I've ignored that - same with standover height because it's pointless comparing as the top tube angle is much more aggressive - so of course the seat tube length is less too..... so really top tube length seems to be the only one worth comparing.

Medium is a diff of -16
Large is a diff of +11

The question is.. size up or size down!?

Cheers,
Saiklist

saiklist

Hmm...

Just reading about reach and stack - seem handy metrics

I had a brief measure of 'reach' last night and my bike came up at 430mm for reach which would indicate a medium would be the better size as the reach for this is 427mm.

I'll measure the stack tonight and see how that compares...

I know I am breaking the cardinal rule of buying a bike here by not trying them first but worse things have happened at sea...

The Rookie

Have you allowed for any setback on either seatpost?

Bear in mind you have +/- 10mm of saddle adjustment anyway.

saiklist

To be honest, I've been ignoring both stem and seat adjustment as I figure as long as I get the right frame size the rest is adjustable to fine tune my setup

(however I'm hoping to avoid having to put a super long stem on or a super short stem on because I should have gotten larger/smaller)

My current bike has had no seat adjustment and sits at 0cm - my current stem is 70mm

I believe the Kona will come with a 60mm stem but I'm not certain (I'm going on the stem on the Kona Honzo)

I sat on a medium Kona Honzo today and the shop assistant reckoned I'd need the large for that bike - It's geometry is totally different and it's a 29er rather than 650b... but it was good to get a feel for Konas sizing - Plus the ETT of the medium is 620! which is closer to the large for the one I'm looking at!

I have also found this useful tool:
http://www.bikegeo.net/

I have mapped out my bikes frame and the medium and large to see how they compare

Looking at the diagrams it would seem my Hardrock 19" is closer fitting to the Kona Large...

Red: Specialized Hardrock Sport Disc 2006
Green: Kona Fire Mountain 2017 MEDIUM
Blue: Kona Fire Mountain 2017 LARGE



The top tubes are more like this though so ignore the silly looking standover height!

saiklist

With stem my current set up is a total 685mm including stem - just been and measured this and it's exactly that.

I suppose this is effectively what I am trying to recreate in this new bike.

Seems I could probably get away with either the medium or the large:

Medium 599mm + 80mm stem
Large 626 + 60mm stem

So I suppose now I just need to decide if I'd prefer a 60mm stem or an 80mm stem.

Thinking about the riding I plan to be doing on this bike I don't intend anything technical - it's purely a commuter, leisurely jaunts and bike packing.

Seems I could probably get away with either frame - lucky me!

decisions, decisions, hahaha!

rockmonkeysc

Bike geometry has changed. Shorter stems are normal and can give better handling when combined with a wider bar.