Author Topic: Gearing  (Read 2447 times)

Re: Gearing
« Reply #25 on: February 28, 2019, 04:44:19 pm »
Not the lovely titanium fixed bike this time Ian?
[/quote]

I'm taking it easy now I'm an OAP.
[/quote]

Not behaving like one thankfully...As a club mate of mine says..Growing up is optional, growing older is obligatory.  At nearly 80 he is proud he is not acting his age.

Looking forward to seeing you at BTS 400.  I enjoyed it so much I am coming back for more!  :)

Re: Gearing
« Reply #26 on: February 28, 2019, 04:50:20 pm »
It depends. If you have a 50/34, or 59/39, etc... then that 50x11 gear gives you 52kph at 90rpm, but if you have a 46 front ring, then the 11t is only 47.8kph, a 40t gives you only 41.6kph. For many that's too low a top speed. Why run such a small large chain ring? because with modern derailleurs, the max size difference is limited to 16t (10t on mtb), so if you want to have a small enough low gear to spin up hills, you need a small enough little ring. This means that for many, an 11t smallest sprocket is actually entirely sensible, it's the crazy 50/34 chainsets rather than 46/30 that is the issue. But I've had this rant before... a few times...

J

I am happy to be doing 95-100 rpm on 46X13 and tucking for that bit extra speed on a decent.
But gear ratios are a personal thing... No rant required  :)

marcusjb

  • Full of bon courage.
    • Occasional wittering
Re: Gearing
« Reply #27 on: February 28, 2019, 05:36:06 pm »
But gear ratios are a personal thing...

Well, indeed.  Some people can push big gears, some people can't, some people spin, some mash.  Find what works for you and get on with it. 

I suspect I am turning very small gears compared to many, but with bits of lung chopped out, I need to be able to gently work my way up the hills at my own pace.  I'd very rarely be able to even turn my top gear of 48/11.

Ultimately, I am sure 'incorrect selection of gear ratios' doesn't come up often as a reason for DNF on PBP (even for fixed, unless you make a massive, late change to your qualification gear).  However, one thing in my own experiences, you'll rarely wish for higher gears towards the latter stages of any 1000km+ ride....
Right! What's next?

Ooooh. That sounds like a daft idea.  I am in!

Re: Gearing
« Reply #28 on: February 28, 2019, 06:09:09 pm »


Ultimately, I am sure 'incorrect selection of gear ratios' doesn't come up often as a reason for DNF on PBP (even for fixed, unless you make a massive, late change to your qualification gear).  However, one thing in my own experiences, you'll rarely wish for higher gears towards the latter stages of any 1000km+ ride....

Achilles and Knee problems do come up as reasons though. Ultimately that's because people are pushing too big a gear.

There's a tendency to decrease cadence as the ride goes on, and when combined with headwinds, especially uphill, the result is tendonitis.

Re: Gearing
« Reply #29 on: February 28, 2019, 06:22:40 pm »
Indeed combining the junior 14-28 with a 11-32. The (ultegra and 105) 11-34 have the last three cogs on a spider (27+30+34) so that would make a mid section of 19-21-24 (27+30+34) instead of 19-20-22-25-28-32.

[...]

So what is the advantage of this over a 14-32 Miche cassette (https://www.internet-bikes.com/130390-miche-cassette-11sp-light-primato-shimano-14-32t/#)? Or can you make a nice 11-28 cassette out of the discarded halves?

Zed43

  • prefers UK hills over Dutch mountains
Re: Gearing
« Reply #30 on: February 28, 2019, 06:41:17 pm »
I prefer the custom 19-20-22-25 over the Miche's  19-21-23-25, but the Miche would work almost as good if your derailleur allows 3rd cog with the small chainring (as I said before the Di2 XT does not).

Given the qualification of the PBP hills I will probably go for the standard 14-28. 32/14 gives ~35kph @ 95rpm (my usual spin, at least until I'm knackered) or 38kph @ 105rpm (that I can sustain for some time when the wattage is not too high). Downhill I tend to accelerate at the top then coast in aero tuck.

Re: Gearing
« Reply #31 on: February 28, 2019, 06:59:00 pm »
In 2015 my front shifter broke about 400m after starting (on the bridge just beyond the velodrome) . So after spinning like a dervish on the granny ring to stay in the groups I reclamped it next morning to the 39t ring. At the back I could use the middle five rings before the chain scraped on the derailleur.  On the way back to Dreux I reclamped the cable to get the big ring (52t)  as it significantly flattens after that all the way back to the finish.

This year my big ring is 46t which I should be able to remain in for longer periods.

simonp

  • Omnomnomnipotent.
Re: Gearing
« Reply #32 on: February 28, 2019, 07:06:41 pm »
The difference between 11-25 and 12-25 is losing 11T and gaining 18T. For me this seems to make sense as it gives me a better overlap between the two chain rings. Top speed at 90rpm is still 48kph which seems fine. I expect to sit at around 25kph most of the time.

Re: Gearing
« Reply #33 on: February 28, 2019, 07:08:00 pm »
I prefer the custom 19-20-22-25 over the Miche's  19-21-23-25, but the Miche would work almost as good if your derailleur allows 3rd cog with the small chainring (as I said before the Di2 XT does not).

Given the qualification of the PBP hills I will probably go for the standard 14-28. 32/14 gives ~35kph @ 95rpm (my usual spin, at least until I'm knackered) or 38kph @ 105rpm (that I can sustain for some time when the wattage is not too high). Downhill I tend to accelerate at the top then coast in aero tuck.

Ah, OK. I prefer 19-21-23-25 (in combination with a 50/34 up front). But then again I'm not preparing for PBP (where I might opt for 50/34 combined with 14-25 if they exist).

Re: Gearing
« Reply #34 on: March 01, 2019, 01:07:17 am »
The difference between 11-25 and 12-25 is losing 11T and gaining 18T. For me this seems to make sense as it gives me a better overlap between the two chain rings. Top speed at 90rpm is still 48kph which seems fine. I expect to sit at around 25kph most of the time.
I would personally rather keep the 11T and miss out the 18T. I've used 12-27 and 12-25 before and occasionally wished I'd had a higher top gear, especially on big descents, not necessarily to pedal constantly, but just the occasional pedal stroke to keep the speed up. I could probably manage with a 25T big sprocket, but I'm used to having a 32T, so I'm going for 28T to make life a bit easier, same as for past PBPs and LELs. My average riding speed was 23.7km/h on the 2015 PBP (20km/h including stops) and maximum speed was 83.5km/h so there must have been a steep hill somewhere!


Re: Gearing
« Reply #35 on: March 10, 2019, 10:11:52 pm »
Slightly off-topic, but how are the hills in PBP? Say compared to the Howardian Hills, Yad Moss and the northern bits of LEL? (yes, I can look at the elevation profile, but for those of you who have done both, what are your subjective impressions?)
Much easier than any of these. PBP is largely long gradual ascents and descents, though there are a few short steep ones, particulrly at the Paris end (though the change of start/finish may have changed this). I don't know of anywhere in the UK which is directly comparable, maybe Oxfordshire/Warwickshire is closest. Anyway, don't worry about them, they aren't difficult.

Getting back to gearing, I'd just use whatever you have on the bike and are comfortable with. The challenge is the distance, not the gradients.

The three toughest climbs, from memory, were the steep grade up to the centre of Brest, (don't remember that) which is on the route again; the long ascent back to Mortagne-au-Perche, (or that) which just seemed to get steeper and steeper, and went on forever after 1000km, which is on the route again; and the climb back through the forest to Paris, (now that...) which is NOT on the route this year.  None of the three required "mountain" gears and the first and last could be walked in under five minutes if you really had no legs left. On that basis, it sounds like this year's parcour is flat. ;D

And Yad Moss from either side is a much tougher prospect than Le Roc.

Really it's the constant rolling that's hardest — for most of the ride you're either going up or going down, there's not a lot of flat for most of it, IIRC.
Your next 1200's your best 1200.

Re: Gearing
« Reply #36 on: March 11, 2019, 11:05:28 am »


Really it's the constant rolling that's hardest — for most of the ride you're either going up or going down, there's not a lot of flat for most of it, IIRC.

Seemed pretty flat to a Devon resident.

I think I was the lowest-geared of the fixed crowd last time, at 43x17.  But that's still a 67" bottom (& top of course) gear; it got me up all the hills without grovelling.

simonp

  • Omnomnomnipotent.
Re: Gearing
« Reply #37 on: March 11, 2019, 11:23:11 am »


Really it's the constant rolling that's hardest — for most of the ride you're either going up or going down, there's not a lot of flat for most of it, IIRC.

Seemed pretty flat to a Devon resident.

I think I was the lowest-geared of the fixed crowd last time, at 43x17.  But that's still a 67" bottom (& top of course) gear; it got me up all the hills without grovelling.

I have used 47x19 both times (69"). I would normally use around 65" on UK routes. PBP lacks any steep gradients that would require walking.


LittleWheelsandBig

  • Whimsy Rider
Re: Gearing
« Reply #38 on: March 11, 2019, 11:25:43 am »
Most parts of the world seem flat to a Devonian cyclist...
Wheel meet again, don't know where, don't know when...

quixoticgeek

  • Mostly Harmless
Re: Gearing
« Reply #39 on: March 11, 2019, 12:15:07 pm »
Most parts of the world seem flat to a Devonian cyclist...

The world is made of mountains to a Dutch cyclist...

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

citoyen

  • Cat 6 Racer
Re: Gearing
« Reply #40 on: March 11, 2019, 01:02:57 pm »
However the bike's got Di2 and the synchro-shift makes it much easier to switch seamlessly through the sequence.

I’d like Synchro Shift on my bike but it would require a battery upgrade. Do you reckon it would be worthwhile?

citoyen

  • Cat 6 Racer
Re: Gearing
« Reply #41 on: March 11, 2019, 01:04:15 pm »
It still puzzles me why anyone in our game (or any non professional) would want the ubiquitous 11 sprocket that the big manufactures try to trust upon us!

I have no need for an 11-tooth sprocket but off-the-shelf cassettes are a lot cheaper than custom ones...

Re: Gearing
« Reply #42 on: March 11, 2019, 01:19:10 pm »


Really it's the constant rolling that's hardest — for most of the ride you're either going up or going down, there's not a lot of flat for most of it, IIRC.

Seemed pretty flat to a Devon resident.

I think I was the lowest-geared of the fixed crowd last time, at 43x17.  But that's still a 67" bottom (& top of course) gear; it got me up all the hills without grovelling.

I have used 47x19 both times (69"). I would normally use around 65" on UK routes. PBP lacks any steep gradients that would require walking.

I'm taking 79" again.   Not a spinner.

Pichy was still giving me a kicking when I tried to keep up with him on the 2nd day.

simonp

  • Omnomnomnipotent.
Re: Gearing
« Reply #43 on: March 11, 2019, 03:34:06 pm »
However the bike's got Di2 and the synchro-shift makes it much easier to switch seamlessly through the sequence.

I’d like Synchro Shift on my bike but it would require a battery upgrade. Do you reckon it would be worthwhile?

If all you need is a battery I’d do it. It’s nice not to have to think about it and in the dark when you forget which chainring you’re in especially.

bludger

  • Randonneur and bargain hunter
Re: Gearing
« Reply #44 on: March 11, 2019, 03:50:32 pm »
I did the Kent Invicta Grimpeur on Sunday and was very, very glad for my 34-32 combo for the top of York's Hill! Might have been able to grind it in 34-30 but 34-28 would have required getting off and pushing.
Bikepacking bargain basement: reviews of high value kit great for the tourer, bikepacker and randonneur on a budget

https://yacf.co.uk/forum/index.php?topic=109048.msg2312359#msg2312359

Zed43

  • prefers UK hills over Dutch mountains
Re: Gearing
« Reply #45 on: March 11, 2019, 07:04:27 pm »
I have no need for an 11-tooth sprocket but off-the-shelf cassettes are a lot cheaper than custom ones...

Miche has quite a range of cassettes starting with a "sensible" starting cog (even a 18t!) and in addition Malcolm has several custom configurations  available for £65.

Also, the Shimano 14-28 is on sale at the moment for 45 euro.

zigzag

  • unfuckwithable
Re: Gearing
« Reply #46 on: March 11, 2019, 07:10:42 pm »
I did the Kent Invicta Grimpeur on Sunday and was very, very glad for my 34-32 combo for the top of York's Hill! Might have been able to grind it in 34-30 but 34-28 would have required getting off and pushing.
that's fine, however nothing to do with pbp..

citoyen

  • Cat 6 Racer
Gearing
« Reply #47 on: March 11, 2019, 07:54:03 pm »
I have no need for an 11-tooth sprocket but off-the-shelf cassettes are a lot cheaper than custom ones...

Miche has quite a range of cassettes starting with a "sensible" starting cog (even a 18t!) and in addition Malcolm has several custom configurations  available for £65.

Also, the Shimano 14-28 is on sale at the moment for 45 euro.

Interesting, thanks! A custom 14-32 would probably be my ideal, and it’s listed as a possible combo. The standard 14-28 would also be an attractive option at that price - and, more to the point, would give me plenty low enough gearing for PBP. (Current configuration is 50/34 x 11-28 and that’s fine for most rides, even moderately hilly ones - it’s only occasionally I find myself looking for a lower gear, though I did the invicta grimpeur on this set-up a couple of years ago and didn’t need to get off and walk on Yorks :smug: )

Re: Gearing
« Reply #48 on: March 11, 2019, 08:49:16 pm »
I’d like Synchro Shift on my bike but it would require a battery upgrade. Do you reckon it would be worthwhile?

It's nice but the shift between rings is still pretty clunky plus I usually find myself manually shifting the rear derailleur to something else straight after the synchro shift.

In other words, it's nice that it forces you to shift the front derailleur at the right time but it's still a long way from seamless sequential shifting.

jiberjaber

  • ... Fancy Pants \o/ ...
  • ACME S&M^2
Re: Gearing
« Reply #49 on: March 11, 2019, 10:32:18 pm »
I’d like Synchro Shift on my bike but it would require a battery upgrade. Do you reckon it would be worthwhile?

It's nice but the shift between rings is still pretty clunky plus I usually find myself manually shifting the rear derailleur to something else straight after the synchro shift.

In other words, it's nice that it forces you to shift the front derailleur at the right time but it's still a long way from seamless sequential shifting.

I agree - it could do with being quicker moving - sometimes it's a bit slow and need some pre-thought on the downshift.  I just run in normal shit at the moment, might switch back at some point though having a cassette (the 11-34) that's not on the drop down when configuring means I have to do some mental juggling to get the right down/up shift points on the front.
Regards,

Joergen