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flyingelephant
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Joined: 06 Jun 2005
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 Posted: Wed Jul 29, 2009 9:58 am Post subject: Bigger gears for TT's than road racing? |
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I do road racing on a 50/36 front and 11/23 rear cassette. Having recently changed groupsets from 53/39 front and 12/25 cassette. I used this for TT's road racing and tri's on a road bike. I'm happy with both these setups.
BUT, I now have a tri/TT specific frame. Should I use the same gear ratio, or something bigger like 52/39 front and 11/23 cassette.
I'm not changing out the cassette. Just the chainset. So the choices are with a 11-23 cassette:
Chainset
53/39
52/39
50/34
I guess I could change the 34 inner to a 36.
HELP!
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CarltonG
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| Posted: Wed Jul 29, 2009 10:07 am Post subject: |
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Guess this depends totally on you as an individual - if you are a spinner you shouldn't need to change. Perhaps best to try a few TT's then see if you are running out of big gears... if you are make the change - if not, putting bigger gears on for the sake of bigger gears tends to make you want to push them... if that's not your thang then you will go slower!
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mattr
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| Posted: Wed Jul 29, 2009 10:12 am Post subject: |
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A duathlate i used to train with set his bike up with the same basic ratio range, but using a 56/57T big ring and a 13 up cassette.
Gave him the same basic cadence/speed, but smaller ratio steps between the gears.
Seemed to work ok. |
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Rob of the Og
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Joined: 12 Jan 2005
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| Posted: Wed Jul 29, 2009 10:18 am Post subject: Re: Bigger gears for TT's than road racing? |
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| flyingelephant wrote: |
I do road racing on a 50/36 front and 11/23 rear cassette. Having recently changed groupsets from 53/39 front and 12/25 cassette. I used this for TT's road racing and tri's on a road bike. I'm happy with both these setups.
BUT, I now have a tri/TT specific frame. Should I use the same gear ratio, or something bigger like 52/39 front and 11/23 cassette.
I'm not changing out the cassette. Just the chainset. So the choices are with a 11-23 cassette:
Chainset
53/39
52/39
50/34
I guess I could change the 34 inner to a 36.
HELP! |
50x11 is actually bigger than 53x12, and there isn't a huge difference between 50x11 and 53x11. If you already have the TT bike and it has a compact chainset then you won't lose much by sticking with it, but if you're starting from scratch you might as well go with the 53. Will you actually ride any TT's or tri's where you'll be using a 34x23?? |
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flyingelephant
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| Posted: Wed Jul 29, 2009 11:23 am Post subject: |
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If I need to use the 34-23 i'd bring out the road bike with clip ons I think!
I don't want to be grinding up hills as most TT are rolling or hillyish. I use 175 cranks with a cadence of about 80 to 95 mainly.
With the extra aero advantage and body position, would the bigger gears be easier to push?
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Rob of the Og
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| Posted: Wed Jul 29, 2009 11:33 am Post subject: |
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| flyingelephant wrote: |
If I need to use the 34-23 i'd bring out the road bike with clip ons I think!
I don't want to be grinding up hills as most TT are rolling or hillyish. I use 175 cranks with a cadence of about 80 to 95 mainly.
With the extra aero advantage and body position, would the bigger gears be easier to push? |
If you mean, "will I go faster?" then the answer should be yes if you can get a more aerodynamic position. Your body position on a TT bike may well make it harder not easier because the reduced hip angle will reduce your power output, but the benefits from aerodynamics will outweigh this at speed.
As I say though, 50x11 is bigger than 53x12 and 53x11 is only 6% bigger than 50x11 (same same effect as riding 50x11 at 85rpm instead of 80rpm) so you're not talking about enormous increases in gear sizes. |
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Tucker
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| Posted: Wed Jul 29, 2009 11:26 pm Post subject: |
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| If you're spinning out of a 50x11 in a TT, then you've got bigger problems, such as whether to sign for Astana or Saxo Bank. |
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flyingelephant
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| Posted: Thu Jul 30, 2009 8:56 am Post subject: |
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| Tucker wrote: |
| If you're spinning out of a 50x11 in a TT, then you've got bigger problems, such as whether to sign for Astana or Saxo Bank. |
How about Lances new team or Sky?
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CarltonG
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| Posted: Thu Jul 30, 2009 9:22 am Post subject: |
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I don't necessarily agree with the if you can spin out on a 50x11 you should be a pro - unless you mean whilst either on the flats OR uphill? I am NO where near pro level yet have out spun myself on 53x11 and therefore have pushed that envelope to a 56x11 this year - some people can comfortably spin at massive cadences and others are gifted with a bit more strength versus straight speed. Seemed natural to me when I realised I was bobbing around like an idiot down hill that I WANTED a bigger gear... what the 56x12 allowed me to do was nearly mimic 53x11, then I just have another gear for that situation where I want to go faster but my legs won't...
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Billy Boy
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| Posted: Thu Jul 30, 2009 10:28 am Post subject: |
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| CarltonG wrote: |
| I don't necessarily agree with the if you can spin out on a 50x11 you should be a pro - unless you mean whilst either on the flats OR uphill? I am NO where near pro level yet have out spun myself on 53x11 and therefore have pushed that envelope to a 56x11 this year - some people can comfortably spin at massive cadences and others are gifted with a bit more strength versus straight speed. Seemed natural to me when I realised I was bobbing around like an idiot down hill that I WANTED a bigger gear... what the 56x12 allowed me to do was nearly mimic 53x11, then I just have another gear for that situation where I want to go faster but my legs won't... |
So are you doing 17 minute 10s?
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CarltonG
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| Posted: Thu Jul 30, 2009 11:22 am Post subject: |
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Not quite but I am capable of going quicker down a hill using a 56x11 than I could with my 53x11... my speedo says so 
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wobbly
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| Posted: Thu Jul 30, 2009 11:40 am Post subject: |
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| CarltonG wrote: |
| I don't necessarily agree with the if you can spin out on a 50x11 you should be a pro - unless you mean whilst either on the flats OR uphill? I am NO where near pro level yet have out spun myself on 53x11 and therefore have pushed that envelope to a 56x11 this year - some people can comfortably spin at massive cadences and others are gifted with a bit more strength versus straight speed. Seemed natural to me when I realised I was bobbing around like an idiot down hill that I WANTED a bigger gear... what the 56x12 allowed me to do was nearly mimic 53x11, then I just have another gear for that situation where I want to go faster but my legs won't... |
grrrr  |
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Tucker
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| Posted: Thu Jul 30, 2009 11:42 am Post subject: |
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| You've spun out of a 53x11? At a fairly relaxed 120rpm that's over 45mph - that's a hell of a TT course. |
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Des
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| Posted: Thu Jul 30, 2009 11:45 am Post subject: |
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It is possible on several TT course with "gift" hill starts. Marlow 25 course springs to mind.
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mattr
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| Posted: Thu Jul 30, 2009 11:47 am Post subject: |
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| Tucker wrote: |
| You've spun out of a 53x11? At a fairly relaxed 120rpm that's over 45mph - that's a hell of a TT course. |
| Des wrote: |
| It is possible on several TT course with "gift" hill starts. Marlow 25 course springs to mind. |
Please note, definitions of "Spun out" may vary. A lot. |
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CarltonG
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| Posted: Thu Jul 30, 2009 12:41 pm Post subject: |
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I guess we are in the post high cadence era that Lance re-publicised but somebody the likes of Nik Bowdler - of Time Trialling god like status pushes a 77 front chain ring and use a 11-19 rear block - at about 50-60rpm, I believe. All my point demonstrates is that for me - 120 is not really comfortable - I don't have a huge lung capacity... I can however leg press 300kg plus... ergo am more comfortable in around the 80-90 range... Not doing 45mph in too many TT's so not even on gift hills - but as I push a 56x11 on the flats at 30 ish mph - I find it easier to do so than doing the same speed in a smaller gear. Each to their own and all that but I think in the cadence argument the best anecdote I heard was if your lungs are burning and legs are ok you should probably look to bigger gears - the reverse is obviously true also - then again WTFDIK 
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Billy Boy
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| Posted: Thu Jul 30, 2009 1:44 pm Post subject: |
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| CarltonG wrote: |
| I guess we are in the post high cadence era that Lance re-publicised but somebody the likes of Nik Bowdler - of Time Trialling god like status pushes a 77 front chain ring and use a 11-19 rear block - at about 50-60rpm, I believe. All my point demonstrates is that for me - 120 is not really comfortable - I don't have a huge lung capacity... I can however leg press 300kg plus... ergo am more comfortable in around the 80-90 range... Not doing 45mph in too many TT's so not even on gift hills - but as I push a 56x11 on the flats at 30 ish mph - I find it easier to do so than doing the same speed in a smaller gear. Each to their own and all that but I think in the cadence argument the best anecdote I heard was if your lungs are burning and legs are ok you should probably look to bigger gears - the reverse is obviously true also - then again WTFDIK |
Or just get fitter. 
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NikB
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| Posted: Fri Jul 31, 2009 11:02 am Post subject: |
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| Tucker wrote: |
| You've spun out of a 53x11? At a fairly relaxed 120rpm that's over 45mph - that's a hell of a TT course. |
I regularly hit 45mph.
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NikB
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| Posted: Fri Jul 31, 2009 11:04 am Post subject: |
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| mattr wrote: |
| Tucker wrote: |
| You've spun out of a 53x11? At a fairly relaxed 120rpm that's over 45mph - that's a hell of a TT course. |
| Des wrote: |
| It is possible on several TT course with "gift" hill starts. Marlow 25 course springs to mind. |
Please note, definitions of "Spun out" may vary. A lot. |
Spinning for me is about 120rpm which makes my legs hurt a bit but 60mph is fun 
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mattr
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| Posted: Fri Jul 31, 2009 11:09 am Post subject: |
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| NikB wrote: |
| mattr wrote: |
| Please note, definitions of "Spun out" may vary. A lot. |
Spinning for me is about 120rpm which makes my legs hurt a bit but 60mph is fun |
And as a comparison, i ride with a guy who 'spins out' when he gets to a cadence of about 90..... personally, 120 is fine/sustainable, pain sets in at about 140, and i can exceed 160 with out any issues (except the pain, coordination is ok tho). |
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