Carbon + Scandium Q

I have a choice of 2 cross bikes, both exactly the same but one is all scandium and the other is the same bar the seatstays which are carbon. I was just wondering if there is going to be any noticeable difference at all in the ride?
Reason i ask is that i can pick the full Scandium one up now but the other i'll have to wait for

CF will be softer on your rear end.
It does make a difference.

Hmmm i could do with it a bit softer in the rear end, but im an impatient bugger and these are the last 2 bikes left

material is nothinjg without design !

Ah sod it, i can always put a slightly larger tyre on the back 😉

I'm sat here itching with impatience, pictures when i get back!

Which property of carbon fibre will make it sofer?

CF will be softer on your rear end.

Rubbish. Will make sod all difference on a crosser. CF stays are nothing but a marketing thing – personally I'd go for the full aluminium one (I refuse to call something "scandium" when that's only a minor component of the alloy).

even microalloying makes a massive difference to the final properties

even microalloying makes a massive difference to the final properties

Which final properties? Are you suggesting that it makes it completely different to other aluminium alloys?

What exactly is meant by 'softer'?

You won't notice any difference, a designer for a 'large' manufacturer once told me that the only reason the offered a carbon rear end on their bikes rather than all alloy was because they could charge more.

The all Scandium would be my choice.

if scandium was the same as bog standard aluminium it wouldn't have been used for the nose cones and fins on missiles designed to be fired through ice pack from a submarine by the Russians. 🙂

having ridden scandium and aluminium frames of the same design with the only difference being the material, the scandium does ride differently due to the fact that the tubes are thinner and can be designed to give more flex in the right places. It makes a lighter frame too.

I'd go for the full scandium.

I did do, see new bike thread

I'd agree 100% with aracer- go for the all alloy bike.

Depends on the design and lay up of the carbon, but I'd say the scandium bike is likely to have more lateral flex in the stays than the carbon stays.
Scandium back end should be just as comfy, if not a little more comfy than the carbon version.

if scandium was the same as bog standard aluminium it wouldn't have been used for the nose cones and fins on missiles designed to be fired through ice pack from a submarine by the Russians.

7005 isn't the same as 1060, isn't the same as 6061, isn't the same as alu-scandium alloy (in which there is typically <0.5% scandium). They are however all more like each other than they are like steel, or indeed pure scandium. Of course the Russians could have used a different alu alloy – it just so happens that alu-scandium had the optimal combination of properties for their application.

The ride difference in your frames is down to the design, since tube proportions are a part of that. Doubtless the scandium alloy one has a shorter design lifespan than the other one. I'm curious though what you think the right places are for flex and how much flex you think your bike had in these places.

Would you choose a scandium front rigid fork over a CF rigid fork?

Would you choose scandium rear seat stays over a CF rear seat stays?

Look at the range of road bikes that employ CF in the rear triangle on their bikes to great effect, typically the rear seat stays.

The last designer I chatted to about bikes and geometry confessed that he had made it up somewhat when designing the bike I ride. I did not believe him anymore than I do the other designer mentioned here!

Next you'll be telling us there's no difference in the ride of a Ti over an Ali bike frame; thrust me, there is, I owned a Pace RC300, + I still own a CF Merida HT.

Oh, and to my knowledge there's no frame that uses 'bog standard aluminium' (or bog standard Ti or bog standard iron)
Everything uses an alloy of something.

Ti29er, The fashion for Al. alloy frames with carbon rear ends has died a death, Using an often bought-in carbon rear end worked out as cheaper and was incorrectly seen as being higher value by the punters- that was the only reason it was popular for a while.

Would you choose a scandium front rigid fork over a CF rigid fork?

No, because the scandium alloy one would be a more expensive and I'm a weight weenie with a budget 😀

Would you choose scandium rear seat stays over a CF rear seat stays?

Yes-because my full scanduim voodoo is lighter than the later model with the carbon fibre bottom.

I appolgise for the use of the term "bog standard" I didn't mean to offend the metallurgy purists…. I'll go and impale myself on a 7005 alloy spike which is approximately 5-10% stronger than a 6061 alloy as I wouldn't want to cause excessive metal fatigue by my demise.

Sorry tazzymtb, I was trying to get across that the differences between aluminium-alloyed frames, whether alloyed with magnesium, zinc, trace copper, beryllium or the much trumpeted scandium are often only really big in the eyes of the most easily led buyers ( I'd personally rather have a carefully heat treated 6061)
I did BTW run an all alloy fork on a training (road) bike for a while, and to be honest, what tyres/ pressures I was using was more noticable than the fork material.

I did BTW run an all alloy fork on a training (road) bike for a while, and to be honest, what tyres/ pressures I was using was more noticable than the fork material.

You obviously don't have the sensitivity of a proper bike rider who's ridden lots of different bikes and can instantly tell the difference between bikes made of slightly different alloys from the way they ride 🙄

aracer, I hope you are bein' sarcastic!
I have the feedback sensitivity of a bicycle equivalent of Valentino Rossi.
.
(..er, in my own head..) 😉

aracer – if that's aimed at me, I owned 2 voodoo frames 1 scandium alloy, 1 alumium. Same size and geometry both designed as xc bikes made the same year with the same components swopped between the frames blah blah. The scandium was definately a more forgiving/lively ride over the same trails to my uneducated 20 odd years of mountain biking arse. sorry if you feel my personal opinon and objective ride experience don't match yours.

I'll go and impale myself on a titanium spike now as the aluminium one failed unexpectedly.

But why can you tell a difference? If it just the stiffness difference between materials then you should be able to make them feel the same just but tweeking wall thickness/tube diameter.
What else makes the difference?

bascially scandium alloy gives a much stronger weld than compared to other aluminum alloys as a result of the precipitated Al3Sc forming smaller crystals than are formed in other alloys. This means that tube thickness can be reduced but still gaining a stronger weld, so a well designed scandium frame will be lighter and stronger (at the welds, don't drop one in rocks!!)

If you're racing cx.Buy 2 cheap frames and run 2 bikes.

I'm still struggling to get what words like 'forgiving', 'lively' and 'softer' mean in measureable engineering terms like stiffness and tensile strength.
You should be able to make a frame with the same 'feel' (whatever that is) in any material by adjusting the tube size but keeping the geometry the same. True or not?

richmars have a look at the linky

http://www.eastonbike.com/downloadable_files_unprotected/r&d_files/R&D-03%20Scandium.pdf

Thanks for the link, but still lots of words like whippy and feel.

http://www.springerlink.com/content/y02t00305p46qq60/

full laboratory analysis of microalloys

hope that helps 😀

Unless it defines what whippy, feel and softer mean, no it won't help. I'm just a simple engineer trying to understand what I'm supposed to be feeling when I ride a bike. At the moment, it seems like the cycling version of hi-fi speaker cables.

been out on lots of road bike that are alu and lots that are alu with carbon stays.i reckon you get a more damped ride on the carbon stays.on average.
depends on the bike though.