Fixed Time Trial Bikes

That's strong stuff Colin.

My Burls is progressing slowly, but should be ready for March. I'll seek out a local 10 and promise* to post my first time if you post yours...

• Unless it's over 30 mins, in which case I'll pretend I didn't ever finish the bike.
  

Thats awesome Colin.

It doesn't really apply to the bikes on the previous page, but there seems to be a bit of a trend to slam the base bars and then have a load of spacers between the base bars and the extensions. Wiggins, Bottril, Tester and upsidedown are all doing it to a greater or lesser degree, whereas others like mine have a scoble stack under the stem and keep the base bar and extensions on a roughly similar level.

Whats the rational behind the "slam dat base bar" approach?

Bottrill doesn't have a normal stem so it's probably trickier to adjust height. Wiggos has spacers or is that a single fixed block of carbon under his 'stem'?

Far as I can tell, comfort. I find breathing much easier at elevated elbow height, whereas my bullhorn positions are fine.

I wittled my spacers out of a plastic pen and long bolts. :-S

Honoured to be mentioned alongside Wiggins, Bottrill and, er Tester. I've done it because if I have the base bar at the same height as my extensions it feels far too high compared to where i'd normally have the drops. I'd prefer it lower still tbh.

Should be more aero, as the frontal area of the riser stacks is less than the taller headtube/scoblestack that would be required to put the extensions in the same position. Should mean you're lower when on the base bars as well.

Ordinata, you should try some s bend extensions, very few people find straight extensions comfy. My Zipp race ones feel perfect.

Yes. Did cross my mind. Mine is damn comfy now tho. If not fug ugly.

Should mean you're lower when on the base bars as well.

https://default.secure.media.ipcdigital.co.uk/11141%7C000007f76%7C98e3_london12-men-tt-wiggins.jpg

If Wiggins' base bars were directly under his extansions here, 70odd mm higher, it'd be harder to get as low.

The lower base bars a la Wiggins etc would give a better sprinting or climbing position, which is probably more relevant to them than us. Presuming we'll spend most of our time on the tribars, their position in relation to the saddle is all that matters, it will be the same unslammed without spacers as slammed with them.

Game on, Hefty, but maybe we should PM our times rather than expose them to Internet glare.... If you go slower than 30, I'll nail a copy of your time to every tree and telegraph pole in the Cambridge area. Dying to see your fabled Burls!

Hefty will go under 30, I'm quite sure. I managed that on an EDCC course with minimal training on a road bike with drop bars.

^I know that, you know that, but does HE know that!?

Indeed, I ask because I'm planning a slight tune up of my bike. I like the position of my elbow pads but I've never liked the extensions - they're too long and I think I'd prefer S-bends.

It's stupid, but the bike originally came with the extensions on a similar level to the base bar and so I fiddled about until I found the height I wanted the extensions to be and thus set the height of the base bar entirely by accident. As it happens this mightn't have been a bad thing because my bike (as pictured) is set up for Ironman rides and so setting the base bars high might have allowed me some extra comfort and a slightly more upright position when climbing. This year however I expect that if I race at all it will only be shorter TTs so the base bars will only come into play at the turns so I might try slamming them a bit.

Presuming we'll spend most of our time on the tribars, their position in relation to the saddle is all that matters, it will be the same unslammed without spacers as slammed with them.

So you might as well have a slammed base bar with spacers. Lower base bar will reduce centre of gravity for cornering too.

^Spot on, but very few spacers with the bars and in all honesty I have yet to fiddle with my position so as yet it's not fully finalised. At my level I suspect the difference will be approx 'bugger all'.

Wiggins and Froome are both tall, so I suspect the risers are also to allow for minimal frontal area of frame and low top tube as well. For us vertically challenged mortals a small frame frontage can be achieved without them.

^^^^ Ssshhhhh. I won't tell him if you don't...

there seems to be a bit of a trend to slam the base bars and then have a load of spacers between the base bars and the extensions. Wiggins, Bottril, Tester and upsidedown are all doing it ...Whats the rationale behind the "slam dat base bar" approach?

I like the lower base bar because it seems to improve handling in the corners and lets me stay low even when on the base bar when climbing etc. Compared with my Koga, the T3 has allowed me to drop the base bar 40mm and stick 60mm risers under the elbow pads, rather than the 20mm I had on the Koga.

As others have mentioned, there might be an aero advantage to having a short head tube/steerer and tall risers, but apparently there is also an aero advantage to picking one of two options;

1. Extensions in line with the base bar (e.g. Easton Attack TT, Planet-X, USE Tula)
   
2. Extensions well separated from the base bar
   
   

with short risers performing worse than either extreme. Roughly speaking, you either put your base bar right behind your hands and accept that the flow over it will be crap but it doesn't add any frontal area, or you put your hands far enough above the base bar that the crap flow coming off them doesn't interfere with your base, and then you need a base bar which works well in clean flow, i.e. a good aerofoil.

I like the lower base bar because it seems to improve handling in the corners and lets me stay low even when on the base bar when climbing etc. Compared with my Koga, the T3 has allowed me to drop the base bar 40mm and stick 60mm risers under the elbow pads, rather than the 20mm I had on the Koga.

As others have mentioned, there might be an aero advantage to having a short head tube/steerer and tall risers, but apparently there is also an aero advantage to picking one of two options;

1. Extensions in line with the base bar (e.g. Easton Attack TT, Planet-X, USE Tula)
   
2. Extensions well separated from the base bar
   
   

with short risers performing worse than either extreme. Roughly speaking, you either put your base bar right behind your hands and accept that the flow over it will be crap but it doesn't add any frontal area, or you put your hands far enough above the base bar that the crap flow coming off them doesn't interfere with your base, and then you need a base bar which works well in clean flow, i.e. a good aerofoil.

To what extent does any of this really matter when sitting immediately behind any configuration of head tube/base bar/extensions/risers is something massively larger and less aerodynamic (no reflection)?

^Ah, the fat bastard conundrum.....

Marginal gains/free speed innit, gains that marginal don't matter at my level, but would to a pro (or anyone trying to flog extremely expensive kit to MAMILS).

But, I have bars which are in line with my base bars AND they're S-bend, Tester and Upsidedown approved, double win!

To what extent does any of this really matter

To Wiggins, it matters to the tune of very large sums of money, being the difference between his market value after winning TdF thanks to time gains in the TTs vs. not so doing.

To the rest of us, it doesn't matter. Except that if marginal gains on the bike aerodynamics don't matter, then we might as well just go for a ride and not trouble the timekeeper. So it matters a lot if your hobby is trying to get the best TT times you can.

To what extent does any of this really matter when sitting immediately behind any configuration of head tube/base bar/extensions/risers is something massively larger and less aerodynamic (no reflection)?

Relevant to this, my aerobar set up is probably slower than a nicely integrated setup, but because it allows me to get my arms closer together it's probably (hopefully?) faster overall. A decent position on chunky bars will be faster than a crap one on USE R1s.

I set my first 50 mile PB in 1987, and didn't beat it until 2009, 22 years and about 5 stone later. In 2012 I got within 36s of my 10 mile PB set in 1991, close enough that I still fancy my chances of updating my all-time 10 time. I've set personal course records on the H10/10 in the past couple of years, on roads I've been racing on for well over 30 years.

i know this point has been raised before but does technological advances need to be factored into this somewhat?

Are you suggesting that Tester's T3 is somehow faster than a steel lopro?

I run the stem slammed and the base bar higher up than I could because I ride to every race and its more comfortable that way! worth considering if you cover a lot of miles on your tt bike.

^^^Of course technological advances matter, otherwise how could I con myself that I was as strong 15 years ago as I was in '82 aged 21!? I fear that technology can't save me this time......

Are you suggesting that Tester's T3 is somehow faster than a steel lopro?

It probably is, but the 1987 50 time was set on a steel road bike (my Hirame, you may have seen it), with 12 (count them!) gears. On the other hand, my current 50 mile PB, set on the T3, is 12 minutes faster than what I did in the 80s, so it's still possible that I might actually be genuinely better at 50s than I was a quarter of a century ago.