I’ve traditionally ridden the Nimbus steel 24 ,26, and 29 frames because I appreciate steel for its strength, stiffness, reliability, and the Nimbus steel frames for their lower cost.
This holiday season I found some good deals on some aluminum nimbus Oracle frames and a used KH24, so I drank the kool-aid (so to speak) and got them.
UDC lists all the steel frames as being 810g which seemed suspiciously uniform to me, so I weighed mine to see actual weights so I’d know how much weight I was loosing on the lighter aluminum stuff. I thought I’d share the weights below as I couldn’t find any numbers on the forums or anywhere else.
Disclaimer - My scale isn’t the greatest, measured weights may a vary a bit.
Nimbus Steel Frame Weights (Incl caps, bolts, and Nimbus 2 Bolt Seat Clamp):
24 Inch Muni Frame: 1125g - on my cheap scale
26 Inch Muni Frame: 1175g - on my cheap scale
29 Inch Muni Frame: 1125g - on my cheap scale
Nimbus Oracle Frame Weights (Incl cap /d-brake, bolts, and Nimbus 2 Bolt Seat Clamp):
24 Inch Muni Frame: 585g (521g + 64g seat clamp - municycle.ca)
26 Inch Muni Frame: 589g (525g + 64g seat clamp - municycle.ca) - was 600g on my cheap scale
29 Inch Muni Frame: 608g (544g + 64g seat clamp - municycle.ca)
KH Muni Frame Weights (From http://www.krisholm.com/en/gear/component/frames - not sure if it includes clamp weight)
24 Inch Muni Frame: 646g
26 Inch Muni Frame: 709g
29 Inch Muni Frame: 766g
Aluminum frames save around 500-600 grams (1 - 1.25 lbs). Being that this is probably 1% or less of your total body weight it seems somewhat negligible overall, but I think there are cases where it matters ( and I believe Ive felt an improvement using the lighter frames in these areas).
Jumping: You lift the uni while jumping. I can feel a 1lb difference while lifting the uni. If you’re jumping a lot this probably saves arm fatigue.
Technical Climbing: Climbing on uni while trying to negotiate obstacles is exhausting and one uses a lot of energy moving the uni around (swerving, lifting, jumping). I think the lighter frame could make a difference here.
Carrying: If you have to carry your uni over your shoulder to walk sections (shameful, I know) its nice to have less weight digging into it.
I think wheel/ tire weight makes more difference than frame weight, but that has been discussed a lot already. If you’re mostly rolling on less technical terrain I personally don’t think saving 1 lb of weight is noticeable.
Crmo steel is a great material and is stronger/stiffer than 6061/7075 aluminum when comparing metal properties. That being said, the only uni frame I’ve ever broken was a steel Koxx 24 in frame: it cracked at the weld between the leg and the crown. This is a good example of how build / weld quality prb makes a bigger difference in reliability than steel vs. aluminum tubing.