New Frame
 

Hi all,
I'm thinking of having a new frame built specifically for fixed (120mm OLN, no cable stops etc), which should be great. However, I can't decide whether I should have track ends or an eccentric bottom bracket fitted (a Bushnell EBB for those in the know). The bike will be used for general riding and time trialling in the local 10 & 25 mile events. Any suggestions/ comments?

Cheers, Olly

go horizointal based on what you state the purpose of the frame is...but of course, there will be other opinions.

Track ends Please. The eccentric b/b is mainly usefull on tandems to tighten the timing chain. You will be adding unnecessary weight if you do the b/b and not the track ends, and making the bike rather hard to sell if that occasion should arise.


fixedgearhead

Simplicity is beauty when it comes to bicycle design, in my opinion. Eccentric BBs are pretty cool, but why make it any more complicated than it needs to be?

Track ends, no question about it. Not really even a consideration really. The only time you should even consider an EBB on a single speed is on a disk braked mtn bike. On a fixed road bike, expecially one that you intend to ride fast (extra parts are extra weight) you want track ends.

You want a frame you can track TT on AND ride around town on? Hrmmm......it's possible I guess. Not optimal, but possible. I wouldn't even consider the Bushnell. It adds weight and complexity where it's not really needed. Horizontals will suit you fine.

What are you thinking here? Going Aluminium or -?

Go with the standard BB with adjustable track ends. The eccentric will screw up up in more ways than you can imagine. You'll need to change your seat height every time you monkey with that BB. It's heavy. Ugly. Complicates things. I can't think of any reason why you would want the eccentric - unless you want to monkey around with your BB height.

Check out my new ride I had custom built HERE: http://www.fixedgeargallery.com/2004/c/mccarthy.htm. After 25 years of riding "compromised" fixed gear I finally had one built the way I needed it. It's got a low, low BB like all the road frames I ride, so it's STABLE yet still fast-handling due to the parallel 74-deg angles. It's got TWO bottle cage braze on for my long rides,.... well, you get the picture.

Go ahead and get that custom built exactly like you want it. You won't regret it.

kennytosh

Thanks for the replies fellas; I have been persuaded to go with the track ends, which was really my intial feeling.


Firstly, not track TT, road time trails - fixies are quite common in the local clubs for TTs, espcially the 10 mile, my fave, and currently done on a bodged fix.

I was thinking of something with angles like 73.5 degs. HT and 75 degs. ST, probably with a head tube length of around 11-12cm for a 57cm frame (possibly effective - sloping geometry may be used, I've not decided yet). I may use a set-back seatpost for the road riding, to bring the angle back to something like 74 degs, again another option.

As for the material, well to be honest steel, either TIG'd or fillet brazed - I doubt (and don't really want) lugs will be available for the angles that I'll end up with. My local builder (Steve Goffs, of Upholland, Lancashire, England) uses both Reynolds and Columbus tube sets, intial thoughts were of 825 OS main tubes with a 725 back end. I was thinking of having stainless steel track ends, with the tyre (23mm) about 2-4mm from the ST with the wheel at the front end of the slot.


What can I say, looks great and looks pretty similar to my desired outcome! I too will be going for about a 58mm BB drop, though possibly down to somewhere between 40 and 50 to allow me to use my 172.5mm cranks, and eek out every last drop of power for the TTs :D I may go for the rear brake (fitted stops and drilled bridge) just to keep my options open.

Thanks again for the replies, Olly

I don't know how many time trials you plan to do but I'm guessing this bike will be used more on the street. Have you considered a more 'road' seat tube angle with the seat pushed forward when you TT? Even if you have another bike for the road, this one will be your custom bike and I bet you'll want to ride it alot. I would set the geometry to the type of riding I'd do most.

Another thought. With the rear wheel tucked in close to the seat tube and the seat pushed back, you may end up shifting alot of your weight to the back wheel.

Regardless whatever you decide, having a frame made is a cool thing ... have fun.

Jim