Geometry in real terms

[shinobi]

Hi can anyone shed some light on the real world effect of modern vs old geometry ?
Basically i have a 99 Kona cinder cone 18 frame and a 2011 Giant revel frame in 16 and wondered what the difference in ride and fit would be between the two with the numbers below ?
Kona Giant
head angle 71 69.5
seat angle 74 73
top tube 23 in 21.85 in
chainstay 16.75 in 17.63 in
wheel base 106.4 in 106.9 in
stand over 29.75 in 30.86 in

Cheers Paul

 

[jimwah]

In general terms the old Kona will have you propped up and stretching forward a bit further, and the newer (and smaller) Giant will let you sit back over the back wheel a bit. I find older and larger frames can be less playful but good climbers, and more modern frames a bit more confident all-rounders. I've got relatively short arms for my height, so a longer top tube is a really noticeable factor for me!

 

[shinobi]

In general terms the old Kona will have you propped up and stretching forward a bit further, and the newer (and smaller) Giant will let you sit back over the back wheel a bit. I find older and larger frames can be less playful but good climbers, and more modern frames a bit more confident all-rounders. I've got relatively short arms for my height, so a longer top tube is a really noticeable factor for me!

Thanks for your reply
Im about 5.10 and wondered if it would be too small for me having always ridden 18/19 inch retro frames , i guess thats the real question !

I want a general use bike that i can have disc brakes and a 100mm travel fork on .

On paper the wheelbase looks similar and im sure my M trax although its an 18 has a 21.5 in tt as well .
Cheers Paul

 

[jimwah]

Yeah I'd mock up the Giant and see how it feels, if you feel like a gorilla riding a kids trike then it's not happening but at 6ft tall I'm much preferring the mocked up position on my 17.5in frame versus my normal 19in (although both these bikes have more traditional geo)

 

[Matthews]

Re:

I run a 18"97 Lava Dome with a disc tab on the back , running 100mm Fox forks and modern running gear , with a shortish stem and the geom is really similar to my 2010 Soul , if you stuck 100mm forks on the Cindercone and remeasured the angles they'll prob be even closer to the giant , I'm 5'11" btw .

 

[shinobi]

Re:

Mmmm decisions decisions

I put a set of forks on wheels on the Giant and it looked pretty small and short tbh , actually looked smaller than it is !

Matthews , thats an interesting shot , what length stem are you running ?
mine is the alloy version of the cinder cone by the way ( not that it makes any odds ! )

Cheers for the input .
Paul

 

[Matthews]

Re:

I think it's about 70mm , al lot of the modern steel HT's are just beefed up n tweeked mid to late 90's Kona copies .

 

[cherrybomb]

Re:

Wow! :shock:

That shot of the Kona & Cotic is spooky. The geometry is near identical.

What size Soul is that?

 

[Matthews]

Re:

Cotic is a med so 17.5 , Kona is 18 so very similar , used to have a 17.5 Genesis Altitude frame before I got the soul and apart from disc tab and cable routing it was nigh on identical to Kona , could have just restickered it an most wouldn't have known, The soul has a longer wheelbase but some of that is down to the 140 forks .Kona is much harsher to ride though as it's a tad less sophisticated tubing !

 

[brocklanders023]

Re:

Don't forget to add the height of the bottom bracket in the equation as I find that makes a huge difference. Better to feel like you're in the bike rather than perched on it IMO.

Also I find the biggest difference between retro and modern are things like bar width, fork length and stem length. I prefer forks longer than 100mm so that makes modernising a pre 2000 bike difficult as even if you can get away with longer forks it raises the bb height too much.

I guess it also comes down to what you compare it with. Modern XC bikes will have geometry closer to retro than modern trail bikes in a lot of cases.