Single speed for a triathlon - bonkers or not?

[swee'pea99]

Apologies if this is clearly crazy...I really know nothing about triathlons...but I was googling to see if I could use a fixie for a triathlon, and have discovered that I can't. But there's nothing to say I can't use a single speed. Would this be crazy? It would be on a flat course (London), I'm used to riding a fixie, it saves a lot of weight, and it would demand a lot less fettling. Has anyone done it? Any thoughts?

 

[Flying_Monkey]

[quote name='swee'pea99' timestamp='1282773359' post='1375343']
Apologies if this is clearly crazy...I really know nothing about triathlons...but I was googling to see if I could use a fixie for a triathlon, and have discovered that I can't. But there's nothing to say I can't use a single speed. Would this be crazy? It would be on a flat course (London), I'm used to riding a fixie, it saves a lot of weight, and it would demand a lot less fettling. Has anyone done it? Any thoughts?
[/quote]

Don't see why not in theory. On a flattish course, should be fine.

 

[marzjennings]

I've ridden my single speed in 3 triathlons so far, all very flat courses, and it's worked out fine each time. You do get a few funny looks from the other racers, but as far as I can see the whole point of the riding section of a tri is to hit your cruising and stick to it for the duration. Unless the course is a twisty one where you may need to accelerate out of the corners, one speed is all you need.

You may need to adjust the gear you run in. If you have your bike set up for more urban street riding you should get a smaller cog for the back. I went from an 18 to a 14 to increase my race speed.

Aero bars make a huge difference (easy +2 mph), but take a little bit of time to get used and it's worth a few trial rides before the race.

If you do fit aero bars you may also have to adjust bar height, saddle height and saddle position fore/aft.

I went back to check my results and I managed 19th place out of 73 for my age group. I was 7 minutes off the lead guy in the run, but only 3 for the ride (swim was canceled due to rough seas). The single speed didn't slow me down at all. Just my fat arse in the run.

 

[PpPete]

I was wondering about exactly this the other day.
There seems to be such a massive emphasis on shedding weight on TT & Tri bikes - but if you can't afford a carbon fibre wonder machine, then why not ditch the weight of the gears if it's a flat course.
Makes every kind of sense to me.

Why don't they allow fixies ?

 

[jay clock]

ok, but if it is a flat course you may need to have a big gear to allow you to cruise at a high speed. Typically a singlespeed has a gearing that allows you to climb hills ok.

If you already have a road bike wih gears I would use that. As for hassle fettling gears, I have done dozens of tris, and never seen any fettling going on!

Finally wih regards the last comment, there is not a huge focus on weight for tris and TTs.... more of an aero fixation

 

[swee'pea99]

Hmmm...interesting. So it's not completely deranged! 

I do have a road bike with gears...I just prefer riding my fixie. And I think on balance it's marginally the better/faster machine. As to fettling, what I mean was, if I wconverted it (my fixie) to SS, that would simply be a matter of removing the back wheel and swapping the current fixed sprocket for a freewheeling one. Making it into a geared bike would obviously involve a bit more faffing around. No that that's a deal-breaker...just a consideration. 

I'd also have to get hold of a helmet from somewhere apparently...but that's another story!

PS I'm interested by the aero bars comment. Must say I'd always viewed them as a bit of an affectation. They really make a difference, huh? This whole tri thing is beginning to look a bit more costly than I'd envisaged.

 

[Rob3rt]

Tri bars make a lot of difference, BUT they arent legal in all triathlons, you might only be allowed short draft legal tri bars in your chosen event, wheras iron man etc allow full aero bars.

 

[pash]

Aerobar restrictions only apply in elite draft legal triathlons and the restriction says they must not protrude further than the brake hoods. Apart from that you can use any tri bars you like. They make a big difference as they immediately reduce your frontal area which is the biggest factor in getting aerodynamic and reducing the wind resistance.
I believe fixies are not allowed as a safety issue as they are deemed to be harder to stop than a freewheel bike.
A flat course you will have no problems with a single speed.
good luck

 

[marzjennings]

I didn't spend a penny on my first race ('cept entrance fee) and just wanted to see how I and my bike did. I only started to change things after I really enjoyed my first event.

Yes, I've found aero bars to make a huge difference, but it's not just clipping a pair on, it's also adjusting your riding position to ride as low as possible without impacting pedaling performance. If you ride a fixie I'd guess you can maintain a high cadence, but I've found the further I lean forward into an aero position the harder it is to spin at a high cadence. Ham strings are stretched a bit more and knees are coming up into my fat gut and it's why I had to fit a smaller cog to maintain a good race speed at a lower cadence. If you haven't got time before your race to put the miles in to adjust and learn how to ride in an aero position don't bother. Trying to ride in an aero position for the first time on race day won't help at all.

 

[oldroadman]

I didn't spend a penny on my first race ('cept entrance fee) and just wanted to see how I and my bike did. I only started to change things after I really enjoyed my first event.

Yes, I've found aero bars to make a huge difference, but it's not just clipping a pair on, it's also adjusting your riding position to ride as low as possible without impacting pedaling performance. If you ride a fixie I'd guess you can maintain a high cadence, but I've found the further I lean forward into an aero position the harder it is to spin at a high cadence. Ham strings are stretched a bit more and knees are coming up into my fat gut and it's why I had to fit a smaller cog to maintain a good race speed at a lower cadence. If you haven't got time before your race to put the miles in to adjust and learn how to ride in an aero position don't bother. Trying to ride in an aero position for the first time on race day won't help at all.

Well, if you're daft enough to do tri....aero bars - work above about 37kph, below that the difference is almost nil. Fixed not allowed for safety reasons, and all bikes must have freewheel/two brakes. If you saw some of the riding standards you'd realise why! The aero/weight thing is a fixation with tri people, but if you want to go faster there is a tried and tested method - trian properly and lose excess weight, thus improving power/weight ratio, and it simply does not matter if the course is flat or hilly, it works (in fact there is NO flat road, it all gently rises or falls somewhere along the way, and therefore the body weight loss counts for a lot).
Best of luck...!

 

[Simon_m]

All the ones I've done have said that no fixed or single speed bikes are allowed. I can;t seem to find the text on the Blenhiem triathlon webpage nort the catle series.

 

[marzjennings]

Well, if you're daft enough to do tri....aero bars - work above about 37kph, below that the difference is almost nil.

Err, no, you're way off there. The positive effects of aero bars and/or just a good riding position can be felt at speeds as low as 12mph even without considering head winds.


quote from ... Cycling Math

At 12 miles per hour, about half of your total power is used in overcoming friction, and about one-half air resistance. To go 25% faster you need to increase your power by about 61%.

At 20 mph, four-fifths of your total power is already spent overcoming air resistance. To go 25% faster, you need to increase your total power by 83%.

 

[oldroadman]

Err, no, you're way off there. The positive effects of aero bars and/or just a good riding position can be felt at speeds as low as 12mph even without considering head winds.


quote from ... Cycling Math

At 12 miles per hour, about half of your total power is used in overcoming friction, and about one-half air resistance. To go 25% faster you need to increase your power by about 61%.

At 20 mph, four-fifths of your total power is already spent overcoming air resistance. To go 25% faster, you need to increase your total power by 83%.

I agree that it's about 80% of power at 20mph, but....practical experience suggests otherwise. Theory is all very well, but practice is what counts.
Given that (approximately) the power required to overcome wind resistance increases as the square of the speed, then at 23mph 529 units (measure what you like) are required to overcome wind resistance, whilst at 30 mph 900 units is the figure. Adopting a CORRECT tri-bar position can significantly lower the power required, but this can be mitigated by the sheer discomfort and thus it's simply not worth bothering below the 23mph - or let's be generous and say 20 mph - level. Plus of course the correct position is important, a "praying mantis" style does very little to improve airflow, and the low position which needs careful practice to msximise benefit is the
only way to go. And if we really get into things, frictional losses increase with speed/cadence, plus the energy used in chain deflection causing energy use by heating said chain, etc., etc.......

 

[swee'pea99]

Well I know nothing, but I've just bought some off ebay to have a go and see if it makes a difference!

Incidentally, as to the "All the ones I've done have said that no fixed or single speed bikes are allowed", I was basically going by the British Triathlon rulebook, which specifies that you must have freewheels (ie, not fixed) and brakes both front and rear. I didn't find anything to say you have to have gears. 

 

[Chuffy]

[quote name='swee'pea99' timestamp='1282901389' post='1377086']
Well I know nothing, but I've just bought some off ebay to have a go and see if it makes a difference!

Incidentally, as to the "All the ones I've done have said that no fixed or single speed bikes are allowed", I was basically going by the British Triathlon rulebook, which specifies that you must have freewheels (ie, not fixed) and brakes both front and rear. I didn't find anything to say you have to have gears.
[/quote]
A friend does tri on a single-speed (not sure if it's fixed or not) and said it was very suitable. In fact he was passing plenty of people on 'proper' tri-specific bikes.

Tri-bars - yes they will help. Anything that allows you to reduce your frontal profile is good. I usually find that the difference at cruising speed (usually below 20mph) between riding on the hoods and the drops is about 1-2mph for the same level of input. Tri-bars will help you maintain a lower, more aero position. Yes, they need to be set up properly but that's just stating the bleedin' obvious and fiddling with your position is all part of the triathlon game.

You can spend not a lot on doing tri but from what I've observed it's basically an excuse for middle-aged blokes to go shopping for loads of shiny toys across three different disciplines.