Author Topic: light, agile, comfortable (bike, not me)  (Read 2514 times)

light, agile, comfortable (bike, not me)
« on: April 01, 2017, 04:01:12 pm »
I've been riding fixed since about 1999 swapping between two steel frames: a 531 Ellis Briggs I got made in 84 and a Columbus Gara Diamont from a few years later. They are both road bikes but with horizontal dropouts. The Briggs is 74 x 74 degrees and the Diamont 73 but slightly longer reach. The Briggs is the preferred one. All fine so far.

I bought a Planet X pro carbon frame and put together a geared(!) bike, not particularly aiming for lightness, but just a good quality setup. The biggest surprise was how well it all fitted my dimensions and the sheer comfort yet liveliness of it.

Whenever I go back out on my steel fixed, I am now highly aware of how much it beats me up. The forks are 531 and wonder if carbon ones would make a bit of a difference?
Also the wheelsets are different with the geared using H Plus Son Archetype versus Open Pro for the fixed. Same tyres and tubes on both bikes though. (I use the same type of saddle on both geared and fixed bikes )

Essentially I'm looking for something similar to the pro carbon but for fixed. I'd prefer something light but comfortable. I have never had an aluminium bike and have thought about a Dolan FXE but a bit wary of its steep angles for multi-hour rides. There is the Langster but I'd prefer just the frame so I could put it together myself. I don't like the components on most bikes which is why I always prefer frames only.

There are quite a few ally frames but not many have bottle bosses and I don't want to go down the route of cable clamps etc.

I think my problem is this – my experience of steel is not one of comfort, which seems to be at odds with what people associate steel for. Surely the likes of a Genesis Flyer won't be hugely more comfortable than my 531 frame, or could it?

I have also considered an Eno eccentric hub and trying that with the pro carbon frame but this is quite a hefty-priced thing for an experiment considering the need to use White Industries own sprockets, also expensive. I have seen that someone on here – David S I think – has made a fixie out of a pro carbon but I don't know if this with an Eno hub or a magic gear combination

So, just to recap; light, agile, comfortable, bottle and cable bosses  :thumbsup:

If anyone could give me a little input that would be much appreciated

Re: light, agile, comfortable (bike, not me)
« Reply #1 on: April 01, 2017, 09:26:27 pm »
Do all the bikes have the same tyres and pressures?

Many think this has a greater influence on comfort than frame and fork materials.

fd3

Re: light, agile, comfortable (bike, not me)
« Reply #2 on: April 01, 2017, 11:44:52 pm »
Check out the N+1 in progress thread in this forum (posted by zigzag).  That's the only example of a fixed gear cf bike that I can think of.
[/I could be wrong]

JonB

  • Granny Ring ... Yes Please!
Re: light, agile, comfortable (bike, not me)
« Reply #3 on: April 02, 2017, 07:50:58 am »
Pearson do an aluminium/carbon fork bike but only appears to be available as a built bike (might be worth an enquiry for a frameset), I know someone with a previous model who rates it.  Geometry details are on the website http://www.pearsoncycles.co.uk/pearson-once-more-into-the-breach-4474.html#product_tabs2


Re: light, agile, comfortable (bike, not me)
« Reply #4 on: April 02, 2017, 08:48:33 am »
Wheel's manufacturing inc . Make an eccentric bottom bracket  to fit bb 30 /pf 30 & some of  specialiZed carbon frames   .It Cost about £100.
Four wheels move the body, two wheels move the soul  three wheels Nurses !!!

fd3

Re: light, agile, comfortable (bike, not me)
« Reply #5 on: April 02, 2017, 09:04:53 am »
I think ribble did a fg cf audax bike, but that took 23mm rubber at most iirc.  I think hewitt(?) do one too.
[/I could be wrong]

Re: light, agile, comfortable (bike, not me)
« Reply #6 on: April 02, 2017, 10:51:53 am »
I got a Ti fixed frame made with horizontal road drop-outs.  Dimensions copied from my comfortable Omega Ti road-frame, but with half-an-inch on the chainstays.  Fork is full carbon.

fd3

Re: light, agile, comfortable (bike, not me)
« Reply #7 on: April 02, 2017, 10:58:22 am »
Okay, if addressing only the last requirement:
Frame material is responsible for stress-strain characteristics (the ratio of these is the Young's modulus, stress is force per unit area and breaking stress is important, strain is proportional extension - an idea of how stretchy a material is ... sort of) and density (per size mass).  So in theory something with a high breaking stress would need less of it to hold a bike together and something with a lower density would be lighter.  Aluminium and Ti have a lower YM than steel, but a lower density as well, so you can use more material to get the same breaking point as a steel frame and get it lighter.
However frame material is not all, how you put it together is important too.  For example if you use wider diameter tubing you get something that is stronger, this means you can use thinner tubes of a larger diameter, reducing weight while keeping strength.  If you push this too far you get tubes that can easily get dinged though.
The way you triangulate your frame is important too, with longer tubes flex in more.
Finally cf is slightly magical in that you can get it to flex in one plane but not another, which you can do to some extent with other materials but only by frame design, so cf has less limitations.

When a bike is mass produced the manufacturers make assumptions of what sort of rider will use it and what sort of loads it will be subject to.  So if you buy a bike in a large size it will probably be designed for a 100kg rider, plus some luggage and then an extra 10% for good luck.  So unless you are on the upper end of mass for your height the chances are your bike will be over engineered and heavier that needs be.

The upshot of this is that a clever frame builder can build you a bike that is about the same mass whatever the material ad if you go for a custom steel job you can save weight on your current bikes.  You could get a custom steel frame for a fraction of the cost of a mass produced Ti or cf frame and would pay only a slight weight penalty. 
[/I could be wrong]

Re: light, agile, comfortable (bike, not me)
« Reply #8 on: April 02, 2017, 01:57:48 pm »
Thanks for the input so far.

Brody: I use slightly lower pressures on the steel bike even though they are narrower rims.

Canny Colin: the eccentric BB. Hadn't really thought of that one. Could be an interesting possibility.

Ian H: where did you get your Ti frame if you don't mind? I have sort of considered this but have no idea what Ti rides like. How does it compare to your other rides?

fd3: I'm not sure I want to go the custom route. The Briggs was a custom frame, albeit 30 years ago, narrow tubes etc. I don't see either the Ribble or Hewitt bikes you mention unfortunately.

Re: light, agile, comfortable (bike, not me)
« Reply #9 on: April 02, 2017, 05:46:27 pm »
Both the Omega and the fixed are bespoke.  The fixed is from Qoroz, near Stroud (they design, and source from China).

I think the design and quality of build is far more important than the material.