How much quicker is TT bike than road bike?

[Mulberry]

This question often arises with various scienitific analysis and anecdotal evidence.

Well on Saturday there was the opportunity to compare road bike and TT bike times very closely in the Festival 10 which featured a roadman category. More to the point, 2 riders rode it twice on different machines.

My mate Jon Masters rode his road bike early (no6) and I was keen to compare on a level playing field. Initially we thought his time of 24:42 was slower cos he wasn't feeling so good or maybe wasn't focussed, however his 2nd (P3 full aero) time of 22:30 was only a few secs of his PB for the course and suggested he had reasonable form.

The 2 riders did the following:
rd #6 TT #56 TT advantage
Jon Masters 24:42 22:30 2:12
rd #58 TT #7
Deborah Percival 26:20 24:26 1:54

Looking at both times it would suggest that maybe Jon was actually riding well - I know he wanted to give me a run for my money although I did 22:46 on my road bike. Arguably the 2 testers above are both experienced TTers who would be capable of riding two 10 TTs in fairly rapid succession (eg as you would in a 25m TT) so the times above are pretty representative and obviously the conditions / circuit were identical in both instances. Jon rode his road bike first whereas Deborah rode her TT bike first.

For the record Jon was in fully un-aero on his road bike = no aero hat, no skinsuit but he did have deep section wheels. I think Deborah wore a skin-suit for both but aero hats were not allowed in the road bike category.
I think you could therefore conclude that a full TT rig and kit would gain you approx 2 minutes in a 10, maybe even more on a flatter course than the Holmwood 10.

Chas Hollosi was fastest roadie in 22:30 and the Joe Perrett (National U23 champ I think) won in 20:06!!

Andrew - shame you missed it, I hope you're feeling better now.
MRB (Marcus)

[Mulberry]

Full result here - R = road bike, H = hub gear

[url]http://cyclingtimetrials.org.uk/Default.aspx?&ge482__geka=MoeMaZhZdmGPSYuQ8onYwgAXZDlkUdIJNURFk8E06xxJZDKDHJP_DeP8RsGXPsL9YnxJLLHNPUbxY10EODtwxzYq_WMVYXc-ECeRpCqgUt7kl6u6CI7T42BNLzR6nw5ZKaYUg3AMg5kq4SkRBUe5ir_XU2ps_CKS_BfCIGruVdg9MmiS5mEFJfdCXtGCrDCC&ge482__gevi=bkosVTEcmXX5ekdECVvBmA&gv484__gvac=2&gv484__gvff0=55648&gv484__gvfl0=0&language=en-GB&tabid=109[/url]

[Antloony]

Interested to read that. I'm no TT rider at all but hoped to beat the 25 mins barrier on my road bike when I rode the Holmwood course in one of the evening 10's we did earlier this summer. I failed by 32 seconds Least I now know I'd stand a good chance of doing it on a TT bike with time to spare to admire the scenery

[Andrew G]

Just didn't fancy it having done the President's 10 in the morning Marcus.

It's an interesting comparison and I've ridden that event on both bikes myself before. You can't get a true reflection as you will save something for the second ride, or be fatigued from the first or you wouldn't be riding either 10 as if it was the only race, properly in other words.

I'm not sure what the difference is on say Holmwood but I would put it nearer 1m30s in the "ride both as if they're the only race" ideal scenario. That would stack up with my times over various periods and on various machines on the course. The aero-ness of the rider on their TT bike against their aero-ness on their road bike would also come in to play, I know Deborah looks slippery on her TT rig and is a very smooth rider so may make up more with that over her road position.

[Sylv]

That will be music to Andy W and Darren's ears, who rode road bikes on Sat with pretty impressive times

[img]http://farm5.static.flickr.com/4116/5005060806_7266f40891_b.jpg[/img]

[Jon H]

M'lud, I present exhibit C; 22/08/09 - Team Sanjan Design 10

Ian Cammish Planet X 22:47 (Old Skool)
Ian Cammish Planet X 21:10

Jonathan Hemming Addiscombe CC 24:12 (Old Skool)
Jonathan Hemming Addiscombe CC 23:34

So, between 1:37 faster if you're a multiple champion dude like IC, and 38 seconds faster if you're a muppet who knackers himself riding a 40 year old fixed-wheel bike.

[Mulberry]

There are certainly all sorts of variables to consider on this one and I agree that ideally you would run one TT on a road bike then have 1-2hrs rest and then run another on a TT bike to allow ample recovery yet still experience identical climactic / course conditions.

My personal opinion before was that a fully aero rig gained you about 1min or maybe 1-30. The key factor is your position and your body as that is the biggest obstacle and some people are very low / aero on their road bikes whilst others are very wide / upright on their TT rigs!!
That's why it's quite good to compare times for the same people in the same event instead of trying to compare 2 similar riders on different machines. BTW Jon M is certainly comfortable on his SL2 road bike and should have achieved a low / aero position that and I'm sure he's done a few rd bike TTs this year already.

Interestingly Ben Instone told me recently that his TT times for 10s are only about 15-20s quicker on his TT rig vs his road bike. However he is quite an animal and may just have been going ballistic on his road bike (to prove a point) and as he's sooo big he may not be as aero and slippery on the TT bike as the average bear.

The general consensus is that key things are TT hat and skinsuit plus low position as that way your body is as smooth / aero as possible. You should be able to get pretty low on a road bike with some jiggery pokery, but you'll never get as low or as narrow a profile on a road bike as on a TT rig.

I've done several TTs on road bikes this year (mainly evening 10s) and I use it as good practice to try to tidy up my position and sit as neatly / compactly on the bike as poss (elbows in / head straight / no bow legs etc). I think this helps with RRs as well as it should make you more efficient and it's what I tried to do on the Edinburgh ride as we didn't bother with tri-bars for that either.

Marcus

[Phil H]

People have probably seen the [url=http://www.cyclingtipsblog.com/2010/04/biggest-bang-for-your-buck-in-time-trial-equipment/]bang for buck TT equipment[/url] thing before. Not sure how accurate it is though (like I spent nowhere near $200 on TT bars). I can't believe that a skinsuit and a pointy hat would give me 3 minutes on a 25 - but if I could get it past the finance director it might be worth a shot...

[Peachey]

We have had this discussion many times - cannot justify the cost of another bike though - but I might invest in some tri-bars to see if any significant difference?

24.45 was flat out for me - Andy's sub 24 min was quite impressive and might have been close to the best scratch?

[Mulberry]

Yes I agree that the discussion has gone round a few times on several forums although it's handy to see some actual times in the real world.

The Trick is to get somebody to lend you a P3 - worked for me when I finally got a new PB last year But then I beat that further in 2010 on my road bike with tri-bars, but who knows what I could have done if I'd held onto the P3. Ultimately you're racing against yourself and you know or in your hear whether or not you did a good ride I guess.

Keepin it real!

Marcus

[Andrew G]

Yep it always bounces around and there are too many different factors.
Weather conditions
How aero are you on a road bike
How aero can you get on a TT bike
Power generally drops in a TT position but the aero-ness outweighs it, depending on how much power you lose to how much aero-ness you gain
Different for everyone

The 1m30 I gave was my difference when I rode this event on both bikes a few years ago but I only rode the road bike one (which I did first) at about 85%.

In simple terms the frame and wheels give the least benefit, but a disc looks good and sounds great . Tri-bars are the most important followed by pointy hat and skinsuit. You can put tri-bars on your road bike and get the biggest benefit straight away. The pointy hat benefit is against a standard road helmet so if you ride helmetless then the benefit will be less as a road helmet is about the least aero thing you can stick on your head.

All that aside, great rides by Darren and Andy regardless.

[kieran]

Hey Sylv, you don't have a pic of the intermediate times at the 5 mile mark do you? I went astray on the way out at the first roundabout, overshot the A24 and went down the next road at first, had to turn around and then hopped onto the island in the middle of the roundabout walked a slight bit and then headed down the right road. I know Paul T was taking the times at the turn and I would be curious to see the split.

[Toks]

[quote="kieran"]Hey Sylv, you don't have a pic of the intermediate times at the 5 mile mark do you? I went astray on the way out at the first roundabout, overshot the A24 and went down the next road at first, had to turn around and then hopped onto the island in the middle of the roundabout walked a slight bit and then headed down the right road. I know Paul T was taking the times at the turn and I would be curious to see the split.

[Sylv]

[quote="kieran"]Hey Sylv, you don't have a pic of the intermediate times at the 5 mile mark do you?

[kieran]

[quote="Toks"] ...your time was a bit on the slow side