kaos_jo

Im having a custom titanium track frame built for me (partly to be tricky, partly because i cant find a quality frame around 2-3k aud, they are all either 1k alloy or 7k carbon)

So i am investigating what is going to build up the best for me, and through my investigating i have discovered that there isnt really a hard and fast rule for track geometries, just what works best for you and your track and the racing style you do.

Im fairly new to racing, and i have only had one track bike, which was a 545mm square traditional madison steel track frame. Its great and stiff, but a little on the heavy side. I also felt as though it never stretched me out enough, and i wasnt wiling to go for a longer stem and compromise handling.

there is a school of thought that suggested you should have your track geometry as close, if not the same, as your road geometry. As you spend more time on your road bike, its better for your muscle memory and training to not have a large difference between the two.

So with this in mind i have come up with these geometries. It is aero down tube, and seat tube with a cut away for the wheel.
the chainstays have yet to be determined, as it will depend on the width of the seattube and its cutaway in relation to my wheel, and i will calculate this when i have decided upon the other geometries.

I run a 170mm crank, and the track that i ride on has a 42degree banking.

So what do you guys think? i willing to listen to anyones views on what they think about this set up.

Also i am curious about what fork i will need to run, if anyone has suggestions to this?

Jo

sideshow_bob

I'll answer some of your questions a little later, but I'm curious as you've quoted AUD. Who's building that bike Baum, Thylacine ... inquiring minds want to know ;p

kaos_jo

www.kaoscustombikes.com.au

The titanium tubing is the same as what baum uses (though thats off the record ) they get it built where the tubing is made, tig welded.

melville

What was the seat angle on your old frame? In the size range you are looking at, the effective top tube length changes about 1cm for each degree of seat angle. Going from 545 to 550mm may not be any longer TT if your old seat angle was any steeper than what you have planned for the new frame. Might even play out as shorter, needing a longer stem.

I've ridden 73 parallel (53ish cm frame) and 75 parallel (similar) and it's all about the same at speed (once I got the seat and bars in the right place for me) but the steeper angled frame was a lot nicer in the slow laps of a sprint, with less wheel flop. Unless your builder is himself a trackie, you want less fork offset, maybe 10mm less, than he wants to supply you with.

There are a few threads here discussing frame materials for track--you might benefit by a wee search before you commit copious AUD$$ to a Ti frame.

kaos_jo

I'm basing the geometry off my road bike, to keep them similar, it's a BMC promachine with a 72.5seat angle and 73 head tube angle. It has a tt of 550 andsuits me nicely with a 90stem. My current track frame which I don't have angles for, but I assume as it is more traditional and probably runs 74-75 on seat and head angle. Wouldn't that mean my effective tt is going to be longer not shorter than expected?

And

If you run steeper angles, 75deg, doesn't that giveyoua twitchy front end? At low and high speed? Butyou are saying if i run a more road geometry, the relaxed front end will fold in anyway?

kaos_jo

Also, as the frame I want to build will have fairly horizontal, a 1deg slope, 550 tt wil be pretty much the effective?

Also on titanium as a material, it's an excellent material, I have a hard tail MTB made custom for my by these guys and it's awesome, feels much snappier than alloy, lighter than steel and you don't freak each time you crash as you would with carbon. To my understanding, these benefits will translate well to track. Stacks are inevitable, and I would love to spend 5k on some high end light and stiff carbon or steel frame, but can't justify the cost over titanium which will be stiff and light and snappy. Alloy bikes just feel dead, in my experience.

melville

If your current track bike (545mm TT) has a 74 seat angle, then keeping the BB and bars in the same place and changing to a 73 seat angle, it would need about a 555mm TT. I'm assuming here that the seat remains in the same location relative to the BB and it just ends up in a different spot on the rails with the different seat angle.

Head angle-wise, it's only twitchy if your builder doesn't give you the correct fork offset. The correct fork offset is LESS than he thinks to get you lotsa trail. If memory serves, the 75 head was matched with 35mm offset. It may be hard to find an off the shelf fork with appropriate offset--I had mine made when builders still made their own forks. I had been used to people bouncing off me with my 73 parallel bike, when I got my 75 parallel bike I was even more stable in the pack and had better walking speed handling, with less wheel flop.

carleton

What? There are several aluminum bikes that are superior to Titanium for less than $2000.

Quality carbon fiber bikes can be owned for less than 2,000 AUD and CERTAINLY less than 7,000AUD. You are being dramatic.

Aluminum and carbon fiber frames are present on the elite and world levels. Except for the odd one here and there, titanium frames are absent on the elite and world levels.

There is your problem, right there

A custom titanium bike as your 2nd bike ever isn't the answer.



Why do you think your custom titanium bike will be better than any off-the-shelf bike that is immediately available? What problem will custom solve for you? What problem will titanium (as opposed to aluminum) solve for you?




If the answer is, "Because I want it", then that's fine. But, let's be clear about that up front.

carleton

My point is, that unless you have special needs (unusual body dimensions, unusually high power output, or just want to be different) it's easier, faster, and cheaper to buy an off-the-rack track bike than build custom. Plus, with some materials, you may have an inferior or at least equal product to something that is found at much less expense.

In short, I'm not convinced that custom titanium is worth the cost and time (waiting time) for a new racer. Spend that money on chainrings and coaching fees



EDIT:

Also, the downside of custom builds is that you can't ride them before you spend the time and money producing it. So, who knows if it will be sluggish, twitchy, stiff, or a wet noodle? Off the shelf bikes come with customer reviews, return policies, and test rides.

I've had two custom bikes. A road bike that was worse than the sum of it's parts and a track bike (Tiemeyer) that is amazing.

brawlo

Interesting you want a light bike. I have only been racing for a year and have been doing a lot of reading as I'm currently looking to replace my Cinelli alu frame. Almost everything I read about track racing and frames, is that stiffness is the primary concern. Try lifting a BT when you get the chance. Those are relatively heavy because they are built to be stiff, allowing for maximum power transfer. There's lots of 3k carbon frames out there, but for me at 196cm they are all too small. I have very little to choose from. I was quoted $2k for the top Fuji frame only yesterday but alas it's too small for me and I want a sprint frame, where the fuji is more a pursuit style.

Seriously consider your choice of titanium for a track frame. There's very few of them about and there's generally a good reason for that. If carbon was really so bad that you freaked every time you crashed then anyone who had to pay for their own frames would definitely baulk at them.