TT bike build challenge

Im taking part in a big event (for me) next year one event is a 2.5 km TT flat. I’d like to reap the benefits of a TT bike.
With cost on my mind and as an engineer working with engineers I’m tempted to build the machine from used/ repaired parts at a budget thinking £1000.
Does the community think this is possible and would it be competitive?

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I think building bikes is a really rewarding process and you learn a lot too. I get a lot more pleasure from bikes I’ve built and specced than ones I’ve just bought “off the shelf”.

As for the price, it’s a tight budget but certainly possible. I’d consider an aluminium frame, since the biggest benefit of a TT frame comes from the position it puts you in, rather than the aerodynamics of the frame itself. Then you can spend a decent amount on a set of wheels and TT helmet.

It’s still a fair bit of money/work for 2.5km but the process of building is a fun one

A small amount of the kit was borrowed/already owned, but someone won the UK national 10 mile TT title on a <£1000 bike a couple of years ago.

As to whether it is worth it for a 2.5k TT, only you can answer that. Personally, I’d want to do a lot more TTing before getting a dedicated bike.


Just 2.5km for a time trial? Seems very short. That is almost masters track pursuit territory. Hint hint. Could you do it on a fixed track bike (with brakes of course). They are dirt cheap. You can pick up track and fixed bikes for a few hundred pounds (£300-400). Add pursuit bars and a road fork with brakes and you could be under £500. Crickey, for that distance you could even risk really fast track type tubs (Have a look for cyclinguphill and tubular tyres in google) depending on the road/surface.

Definitely think that £1000 used and second hand example is a great guide and absolute max.
The second hand/used route is the best. I have used that for my TT bike that I have ridden in all distances from 10miles to 12 hours this year. It has served me very well. If you do pick up second hand, just inspect carefully before you hand over cash.

Definitely budget skin suit and pointy helmet though… and you’ll be spending far more time warming up than racing - so how will you do that?

As to competitive - your ability to put out a very high power for 3-4 minutes, and hold it, will be the determining factor - as long as position is aero as well. I would look at track cycling examples for training and ideas.

I hope that helps. What event is it? It sounds unusual.

Sure you didn’t mean 25k?

Anyway. Skin suit. Booties. Pointy helmet will save you more time than a ultra high end frame
Look at 2nd hand groupset and frame.
Do you already have wheels?

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I’ve done exactly what you describe. Built a reasonably priced TT bike from local second hand / eBay parts with a target of £1000. The ‘Bussell Bike’ linked above was used for inspiration.

I ended up with a Cervelo P2, A900 forks, USE Tulas, Planet X disc and HED3 Trispoke. In reality I think I went over budget by maybe £200 - £250 but I ended up with a pretty decent TT rig.

I’m now done with TT (for now at least) and I’m in the process of trying to break even on the resale, I’ll probably loose out a bit but hopefully I’ll end up not too far off.


100% mean 2.5 km which puts doubt in my mind of the benefit of a TT bike but the race could be won or lost by fractions of seconds. So it’s TT bike vs Sworks Tarmac over 2.5 km. :man_shrugging::man_shrugging::man_shrugging:

Time will be dedicated to position in training. Skin suit, helmet boot covers etc all covered by team so can’t be altered.

The bike will need to hit some regulatory standard albeit not UCI but I think a track bike is out.

It’s refreshing to hear that this could be possible the P2 pictured looks great.

The idea could be as much an engineering challenge as anything. So 1x crank means only one shifter and mech. Etc.

I recently picked up a second hand speed concept with carbon rims and zipp cockpit for under 1k € and Ireland is definitely a smaller market. Ild be amazed if you can’t get good value in the UK.

If you were really going to build ild take a long hard look at the cheaper of the planetX options first. Brand new, built, working out of the box. The vast majority of your gains will come from the position rather than anything else.

For a 2.5k TT in a stage race ild question the value of a TT bike. Have you checked the course profile. Those sorts of distances tend to end up being hill climb esque in which case the extra weight of a TT bike combined with the extra difficultly you will have putting out power in an unusual position will very possibly make you slower!

A grand to save a few fractions of seconds. That’s a high price per payback. How important is this race?


It’s a chance in a life time race.

The trials to enter it was a down and up on to cobbles and I lost by 0.13s everyone was on road bikes for that because of the course.

This one is Definitely a flat profile with a very shallow sweeping bend hence the conundrum.

I don’t plan on this being my last TT. I done a good few two years ago but had to sell the bike. I didn’t expect to have the chance at this race.

Im tempted to borrow/ hire a TT bike plot a course and see what the margins are if any.

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  • OK, but I guess what I am asking is, what happens if you win, get 2nd, etc. by a few split seconds? Money, fame, personal satisfaction, etc.? Just curious about the motivation behind the effort and expense.
  • That is all but pointless since you can’t likely control for wind and temp conditions from run to run, let alone the impact from placebo and such. You can’t likely control the test to a level of precision to actually have “real” data that is worthwhile. The difference in time on this short of an effort is minimal at best.

  • You could do better to estimate based on claimed differences on something like comparing the times saved via Specialized info comparing regular, aero, and TT/Tri bikes from their stock info. Those are most often set at 40km, so do a quick divide to find out the difference on 2.5km to see the difference.

  • Again, I expect it to be tiny at best. Getting your position, clothing, and peak effort dialed are likely easier/cheaper gets that are well within reach.

  • I am all for the N+1 and have pushed it myself to the point that I lose count on how many I have unless I sit down and pull off my shoes. Point? If you want a new bike, get a new bike.

  • Trying to justify it with this single event and decimals of seconds is pointless.

If I was you I would be asking @gvmcd what size his bike is, and if it’s the right size then whether he’ll take £1k for it…


So the event is important to me and has been three years build up but the course was only reviewed two weeks ago.

From previous events the difference from first to fourth is a few seconds at best so marginal gains are important. Possibly more so in such a short race.

Regardless of the bike I use I will aim to have every other aspect weighed off. Peak /sustainable power for the event distance that and the crit are my focus for the next 6 months and clothing we don’t have a choice.

If I had the money I’d be buying a £4-5k TT bike but then this question would be moot.

I think I’ve even lost track of my OG question. :rofl::rofl:.

Tri rig base bar and omega brakes on an older Cervelo frame is a popular way to get super-bike performance from an older bike. Helmet helps. Speed suit would help. Body position will be the biggest way to gain/lose time.

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It’s a 51 (I’m 173cm tall). Think the fit of these older style Cervelo is long and low.

Wheels, bar, A900 forks are gone though. I have the frameset with original 3T forks, brake calipers, chainset, rear derailleur still to sell.

Sounds good but too small for me. Great shopping list though thank you.

For a five(?) minute race, borrow one.

I’m not joking. The hours, days, weeks, you spend researching, purchasing and building need to go into training for this once in a lifetime event.

Spend your money on speedsuits and aero helmet.

And I loved building my tri bike.


I agree, with one caveat. Make darn sure any bike you borrow “fits” you so you can put out good power for the full effort. It’s not likely to be a problem for such a short effort, but I’ve seen people on here borrow “faster” bikes only to perform worse than their regular bike, because the positioning on the bike was sub-par. It’s worth considering if you are gaining in one area and possibly losing more in another.

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Did you see Hambini’s latest video series? (Don’t watch if you are offended by bad language…)

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Just seen a guy on facebook market place in the UK selling 2 medium trek speed concepts. a frame for £150 and a part build for £200