Cycling UK Forum

Brucey wrote:
Thorn's logic is slightly flawed

cheers

It usually is but it makes a great read and, if like me, you're in agreement with it then it's quite cheering as well. Personally I would never argue against titanium - I have neither knowledge or experience of it. I think it's like Rohloffs and recumbents (and Marmite) - you weigh up all the factors and something either clicks or it doesn't. If the colour and finish grab you (it doesn't me) and you have the cash, then you're on your way.

horizon wrote:

Brucey wrote:
Thorn's logic is slightly flawed

cheers

It usually is but it makes a great read and, if like me, you're in agreement with it then it's quite cheering as well. Personally I would never argue against titanium - I have neither knowledge or experience of it. I think it's like Rohloffs and recumbents (and Marmite) - you weigh up all the factors and something either clicks or it doesn't. If the colour and finish grab you (it doesn't me) and you have the cash, then you're on your way.

I have a Thorn tandem, supposedly protected by a tough powder coating, that is sat in the garage with paint blistering off. One of the reasons I chose titanium last time.

In my head I was hell bent on building up a Ti framed bike, and after spending over twelve months researching I finally opted for a Kinesis Grand Fondo Ti disc frame. Ordered the frame and as the UK importer had one my size in stock, it was delivered to the shop a couple of week later. We great anticipation I went and collected the frame and it was indeed a thing of beauty. It was all boxed up and wrapped in plastic film, and perhaps I should have spent more time looking at the frame before I left the shop and did my 70 mile drive home.

Once home and with the comfort of the carpeted lounge floor it was all unwrapped, and that when my balloon was well and truly burst! One of the bottle bosses was only welded half way around???

I rang the shop straight away and was questioned if I was sure it was missing, yes really I was asked if I was sure?

The frame was returned the following day, so another 140 mile round trip and I was told that the replacement frame would be 4 to 6 weeks. Fast forward six months and countless emails and phone calls later and still no frame, so I asked for my money back which was given without any hesitation at all.

Then I started looking at the Van Nic frames, very nice and indeed the life time warranty was most appealing. But then I heard of a chap in our club who was on his second Van Nic frame and that had just snapped in the exactly same place as it had before? So then I looked at Engima frames, and once again after talking to people in the club, two people had experienced cracked frames from them to.

But then my focus of attention was drawn to the carbon Trek Domane frames with the Isopeed couplers front and rear. The local LBS had a demo bike so I went out for a 4 hour ride on it, and indeed I would agree with every single write up about them, very comfy! With a lifetime warranty on the frame and is also very light considering it has hydraulic discs and the Isospeed couplers, what is there not to like?

I have a custom built 853 road bike which is my chosen weapon of choice for longer rides, I have a full carbon “best” bike for training bashes and Sportives, and my aluminium bike for everyday ride to work use, and as a person that covers circa 15k miles per year I well qualified to past comment as to how good I believe the Trek to be.

The steel bike is very comfy and indeed rides like a dream, but there is a weight penalty. The carbon bike is awesome and very response, but I can feel every pimple in the road. The aluminium bike, (Kinesis T3) well to be honest it’s a dam good frame for the price and if it wasn’t for the sake of me being greedy, it would probably cover all of my all options. Okay, yes it is a tad heavy, and its not as responsive as the steel bike, but the frame was half the cost.

So in conclusion, and as much as I would have liked a Ti frame, the amount of failures that I have come to hear about has put me right of one now. And I certainly wouldn’t even consider one unless it had a life time warranty on it.

Which sadly ruled out the Laverack Ti frame, this one was the top one on my list until the Trek bowled into my life.

531colin wrote:Something which is currently exercising my curiosity (and which I think deserves much more attention) is tube profiles. Round tubes are traditional and easy, but if you simply ovalise a tube you can make it stiffer in one plane and more flexible in another plane. So ovalise the down tube and the top tube to produce a frame which is both stiffer laterally and more compliant vertically with the same weight of metal as an exactly similar frame with round tubes. (I'm sure there will be people who could calculate the degree of ovalisation required to make the tube twice as stiff one way as it is the other.....but it isn't me!)

https://2.bp.blogspot.com/-xqtlNnoZGyg/V1d0UnAkDhI/AAAAAAAAm6Q/RGiDrwDFL5IvRTl_1q1dvH_plEEzJagOwCLcB/s1600/CiaoRagazziVaBene_Side.jpg

the frame in this photo is built with columbus max steel. the tubes are ovalised as you suggest above but also in the fact that they are ovalised in one orientation at one end of the tube and the other way at the other end. you can see that the chainstays also are oval with the seatstays being slightly more squared off than oval.
i have a road frame made from this stuff. the difference in acceleration is appreciable.

I'd fogotten that my first titanium machine was in fact a Raleigh, the welded one, Colin wrote about early incarnations being flexy, I would agree , the USA, Exxon?? was one of the first and indeed I have read it was like a rubber band with a powerful rider..I appreciate that Raleigh weren't given great accolades for their offerings especially the glued one, however many years ago in the early 00'S Cycling Plus did a test where they had 5 or 6 framesets and tested them on some sort of static rig, the Raleigh ...as mine ..came out top imsw excelled in the lozenge strength or flexing mid section at the bracket .. the tubes afaik were std except the down tube.. will

Yes, the Columbus tubes are ovalised, but the only thing in common with mine is the ovalisation of the downtube by the bottom bracket.....this will give lateral stiffness and vertical compliance. I think this is the major influence on the bikes acceleration.
Ovalisation of the downtube in the opposite direction at the head tube end will result in lateral compliance and vertical stiffness, which is the opposite of what I want from a frame. The only logical reason to do this is if the downtube diameter is bigger than the head tube. (This is a sort-of backhanded advantage of inch and a half steerers.....theres plenty of head tube to stick a big downtube to!)
I'm afraid I think its the same with the front end of the top tube, its ovalised in the wrong plane as far as I can see.....I ovalise it in the opposite plane at the head tube, again for lateral stiffness (against shimmy) and vertical compliance (for comfort).
I can't think of a reason for the odd seat lug cluster or the ovalisation of the back end of the top tube, other than its supposed to look like somebody has thought about it......in which case they came to a different conclusion than mine.
But I do applaud the chainstays, which as far as I can see don't have any dents.
I'm sorry this has turned out to be a bit of a hatchet job, I didn't set out to do that. However, I don't see any point in spending a lot of money just to make something "look different".......and there is a lot of money spent here.....special lugs, and tooling to ovalise the tubes accurately enough to fit the lugs properly. Its a lot less involved with a welded frame, the ovalisation has to be "near enough" but provided you are welding one oval tube to one or more round tubes the mitering is straightforward.