For the best XC frame, what is the best frame material?

Titanium, carbon fiber or fancy alloy (such as specialized M4, etc).

I've heard that
- alloy is stiffer than steel and gives a harsh ride
- titanium is more bendy than steel

If titanium is the ultimate, then i'd expect to see it on specialized S Works XC bikes, as these are the top of the range, but they use their own hi-tech alloys.

So I'm wondering what's best, and why.

anyone know?

If you mean "best" as in "fastest" - a carbon hardtail probably takes a lot of beating.

Ti is more about quality of ride and durability rather than out and out speed as it doesn't make the lightest or stiffest bikes.

Quite personal that one. One should probably talk about hard tails for a fair comparison, as very few companies actually make Ti full suspension bikes as half the point of titanium is the sprung feeling and different design will give different feels etc.

S-Works frames aren't really top of the line, just top of the Specialized line. Its only £700 for the hardtail and M5 is merely aluminium with bits of copper, silicon, magnesium, zinc and whatever Mn is the chemical symbol for (manganese) but they are basically just aluminium frames.

Carbon is known for its stiffness and thus harshness in some respects. They are often said to feel a bit more muted than alu frames because of the high frequency vibration. It can made in 2 ways, a lugged type design like Trek's OCLV's or a monocoque type design like Scott Scale's, which is lighter but more labour intensive and thus more expensive.

Titanium is very hard to work with, which is why most of the mainstream manufacturers don't use it. The raw material is also very expensive, unless Russian titanium or similar is used, as this can be obtained more cheaply. Companies like Litespeed and Merlin are charging up to £2500 for a frame alone in the case of the Litespeed Tanasi. There are different grades of titanium, like 7005 etc in aluminium, given as a percentage of aluminium and vanadium, most ti frames are 3al/2.5v ie 3% alu, 2.5% vanadium. It offers the most compliant ride of all the materials and is generally reckoned to have the longest life. I have always found they don't accelerate quite as well as a carbon frame, due to the slightly more compliant rear end, but do offer a more comfortable ride. 6al/4v titanium is probably the ultimate material as it is stiffer than 3al/2.5v but still maintains the compliance and longevity of the 3al/2.5v frames. In theory, making it the best of all.

Personally, I think my carbon Trek OCLV 9.8 is about the best hardtail frame for an all out race bike. But thats just me...

there's so many typo's in that, really shouldn't try and use BM while I'm at work! Sure it makes some sense, not that anyone's gonna read my inane drivel!

Thanks Nick,

OK, so if litespeed's ti frames are so pricey, why are people buying them and not lighter carbon fiber frames?

and which is lightest? carbon fiber?

and is there any difference between russian titanium and other titanium, apart from the price?

Don't forget there's a major longevity/damage resistance issue with carbon fibre - scratches & knocks are much more worrying in carbon fibre than other materials.

Personally, I'd say go for ti if you can. I love my steel frame, but have been riding a ti test bike for the last 4 months & it's great - just as 'comfy' as the steel frame, but much lighter & of course, rust-resistant.

OK, right now I ride a specialized stumpjumper M4 comp, or something like that.

So if i went for a ti hardtail, what would i notice?

Handles better and weighs less?

Carbon has the reputation for being the most delicate. The frames tend to be highly engineered so they can become very strong in some directions and not in others.

An FS Ti frame is a bit of an oddity - must be incredibly difficult to design. Generally you might think the parts of an FS frame should be as stiff as possible to the suspension do its job.

I guess Russian titanium is the same as everybody elses. What you do get though is a price difference between frames manufactured in Russia and China (Global and Airborne) and frames manufactured in the US (Merlin, Litespeed, Serotta).

Like all materials, the quality of the tubing and the welding has a huge impact on the quality of the frame.

I think the M4 frames are pretty light anyway, so there wouldnt be a huge difference between that and a Ti frame. The main difference would be in the feel of the frame as others have said above.

Handling is primarily a function of shape rather than material, although at the extremes the stiffness of the structure can affect how it goes round corners. You can't really isolate material properties and say, "A bike made out of X will be A, B and C" because there's too much else going on - tubing diameters, butting profiles, frame design, seatpost diameter, tyre size... All the stuff you hear about whippy steel, harsh alu etc are just generalisations. There are harsh steel bikes, noodly aluminium ones and every other combination you can think of.

The main advantage of Ti is that it's highly corrosion-resistant (so you don't need to paint it) and it has a very high strength-to-weight ratio so you don't need to use much of it. It's easier to make a lighter bike out of aluminium, though. For pure XC racing it's probably hard to beat carbon fibre - it can be made to do pretty much anything, it's insanely light but the long-term durability still isn't really established. Although again, those are all generalisations - specifying that a bike is made out of carbon fibre is a little like specifying that a chest of drawers is made out of wood :-)

If you want to check out low cost Ti, try www.airborne.net

Most high end hardtail frames are around 3lbs, my OCLV weighs 3.06, the Merlin XLM titanium frame in the shop weighs 2.93, and S-Works M5 is about the same, so there isnt a massive difference.

People buy ti frames for the 'bike for a life' factor and because of the compliant ride. People buy carbon frames for the ultra light, ultra stiff race feel. Generally!

got two ti frames and wouldn't swap them for anything. the ride is great, but thats about all i can say about it. i reckon thats more down to the fact that they are both well designed, and based on well thought frame geometry and design.

as mike said, corosion resistance is a good thing. i don't like cleaning and polishing.

i think the longevity thing was important to me. IMO ally frames are too stiff anyway and the feel becomes dead after a while. steel rusts and bends. ti does neither of these.

another thing that is a real bonus is the damage resistance. The other week my chain managed to slip above the chainstay, near the crank. i was expecting a huge gouge out of the chainstay, but nothing. not even a scratch. i've written a steel frame off with similar chainsuck.

if you can afford a ti frame, get one. ;-)

I love a steel frame myself. If well looked after they perform in a similarly springy fashion to Ti but are mucho cheaper.
I had a Magnesium alloy frame, it broke after 13 months and not from a heavy landing.

I think the reason the big manufactueres use aluminium alloys for there frames is becasue it's dead cheap and easily molded into different shapes as required.

'i've written a steel frame off with similar chainsuck.'

We had someone put a crack in the chainstay of a Merlin XLM from chainsuck, not brilliant! Cost £350 to get a new chainstay welded in, but it was incredibly well done in fairness.

Thanks for all your comments, it has given me a much better idea of what to look out for, or whether to even change to a ti frame.

Cheers guys!
steve