TT Gearing

markos1963

Thinking of getting a proper TT rig sorted out next year and I was wondering about gearing. The main concern was chainset/rings and I had a thought, do I need to run two front rings at all? Most of the courses I ride are pretty flat and a lot of testers go fixed on them anyway. I never drop into the small ring and I run a compact on my roadbike. The weight saved through not having a ring/changer and shifter must be quite significant and having ten speeds at the back is enough choice for most courses around here. Does anyone else on here run this or have any thoughts on it?

John.T

No reason why not but you should have a mech or chain guide to make sure the chain does not come off. Ask David Millar.

a_n_t

never used my 39 ring during a TT but tend to spin in it riding back to the HQ. Wouldn't be a problem without it tbh.

markos1963

John.T wrote:

No reason why not but you should have a mech or chain guide to make sure the chain does not come off. Ask David Millar.

Good point, would I be able to shim the ring to give me a more central Q line?

John.T

Good point, would I be able to shim the ring to give me a more central Q line?

I guess you mean 'chainline'. If you use a double crank with only the outer ring then not with most setups. If using square taper then you could fit a shorter BB. To be honest it is not really a problem, no different from using the big ring all the time.
You could of course run close ratio rings and always have the right gear available. Personaly I have left the 39 on for grovelling back to the HQ after the event.

hopper1

Markos, are you doing the County champs 25 TT at Wisbech, on the 18th?...

markos1963

hopper1 wrote:

Markos, are you doing the County champs 25 TT at Wisbech, on the 18th?...

No mate well out of my league and I haven't ever ridden a 25 yet. Going to start soon as its supposed to help my 10 times. Once I get into the 25mins area for a 10 I'll start doing 25's more seriously as my main cycling goal is to crack the hour.

Mog Uk

markos1963 wrote:

Does anyone else on here run this or have any thoughts on it?

Yep... Why have all that extra weight on your bike if you'll never use it

I run a single ring up front and only really tend to use the lower 5sprockets on the rear. As has already been mentioned I've kept the front mech purely as a chain guide, just wound it out all the way to prevent chain rub.

Pross

If the courses are generally flat a couple of hundred grammes less won't help you much. Just run closer ratio front rings that way you have the option if you do a more 'sporting' type course. Run a straight through 11 up cassette on the back.

Tom Butcher

If you don't use the inner ring then ditch it - take the point it makes very little difference but you can pay plenty for very small weight/aero savings so why not take them if they are free.

markos1963

Tom Butcher wrote:

If you don't use the inner ring then ditch it - take the point it makes very little difference but you can pay plenty for very small weight/aero savings so why not take them if they are free.

Well this is my way of thinking and as its reciprocating weight it has an even bigger effect than just lightening the bike.

Sheptastic

When i saw 'TT gearing' i immediately thought, 'well 53x11, that's all you need'

markos1963

Sheptastic wrote:

When i saw 'TT gearing' i immediately thought, 'well 53x11, that's all you need'

I wish

sub55

markos1963 wrote:

Sheptastic wrote:

When i saw 'TT gearing' i immediately thought, 'well 53x11, that's all you need'

I wish

cum on 56x11 is the best

tri-sexual

sub55 wrote:

markos1963 wrote:

Sheptastic wrote:

When i saw 'TT gearing' i immediately thought, 'well 53x11, that's all you need'

I wish

cum on 56x11 is the best

so what is the largest commercially available chain ring?
i think some small 20" wheeled folding race bikes use large chain rings to compensate for the small wheels but dont really see them marketed and sold seperately.

graham obree uses a custom chainring the size if a large dinner plate with a fixed wheel.

would love to have a massive chainring on my bike just to scare the opposition

sub55

56 custom beyond that

Pross

There was a photo on here recently of a guy who uses a 70 or something stupid!

John.T

TA go to 60.

sub55

[img][/img]

Matt the Tester

sub55 wrote:

[img][/img]

bloody hell!!

hopper1

steady rider wrote:

sub55 wrote:

[img][/img]

bloody hell!!

No good, if you can only reach a cadence of about 15!

hopper1

markos1963 wrote:

hopper1 wrote:

Markos, are you doing the County champs 25 TT at Wisbech, on the 18th?...

No mate well out of my league and I haven't ever ridden a 25 yet. Going to start soon as its supposed to help my 10 times. Once I get into the 25mins area for a 10 I'll start doing 25's more seriously as my main cycling goal is to crack the hour.

You are sh!tting me... Not out of your league mate... I've been behind you!
And it's my first 25!!! :shock:

blackhands

sub55 wrote:

[img][/img]

That's Nik Bowdler

His TT times are:

10 mile 18:59
25 miile 49:52
50 mile 1:39:02
100 mile 3;37:08
12 hour 289.84 miles

and BTW he uses 165 mm (Tiagra) cranks.

sub55

ow i no :twisted:

Hunterg46

I tend to stay on my 39 ring for a 10miler, and that works for me!