Road Cycling

FrenchTart · 13 Aug 2015 at 12:01

rnickster said:
Weird question, what do people do with worn out bibs/shorts/jerseys ? In the bin/recycle/charity bin ?

Sexy times wear, obvs.

rnickster · 13 Aug 2015 at 12:33

just need to mod with a pair of scissors and hey presto!

Berger · 13 Aug 2015 at 12:35

Roady said:
Guessed that was the case, just don't see bearings mentioned on most sites???

Good going, well done!

Good point. So what we're saying is not much point going ceramic and just to replace with better quality?

Yeah.

Let's say drivetrain losses account for 5% of your power output.

At 300w that's 15w lost through the chain, cranks, bearings etc.

Say the bearings make up 50% of that drivetrain power loss; 15w, that's 7.5w total.

If ceramic bearings are twice as good as steel ones, that's a 3.25w saving.

A quick Google gives a cost of $70 for a ceramic bearing (I guess they can be had for less) vs $6 for a steel one.

Now there are bearings in the rear hub, plus the front hub, the BB, the derailurer pulleys, say 10 all up, $60 for steel or $700 for ceramics.

So that's a cost of about $200 per watt saved.....

Saytan · 13 Aug 2015 at 12:45

Berger said:
Yeah.

Let's say drivetrain losses account for 5% of your power output.

At 300w that's 15w lost through the chain, cranks, bearings etc.

Say the bearings make up 50% of that drivetrain power loss; 15w, that's 7.5w total.

If ceramic bearings are twice as good as steel ones, that's a 3.25w saving.

A quick Google gives a cost of $70 for a ceramic bearing (I guess they can be had for less) vs $6 for a steel one.

Now there are bearings in the rear hub, plus the front hub, the BB, the derailurer pulleys, say 10 all up, $60 for steel or $700 for ceramics.

So that's a cost of about $200 per watt saved.....

Marginal gains!

given that Laurent Fignon's ponytail once cost him the tour de france, if you're racing at a high level there's no good reason *not* to....

R0B75 · 13 Aug 2015 at 12:46

Balb0wa said:
Ive done about 900 miles on my zondas, cant fault them, the wiggle reviews are pretty good overall.

Me last night catching a guy up on Beeley Bar who overtook me at a ridiculous speed going up the previous hill.

The tour of Britain goes up this hill next month, about 2 miles long, one of nicest hills around here for scenery.

https://www.strava.com/segments/2228179?filter=overall

https://www.youtube.com/watch?v=NToQbZksMyc

Never been down this hill but I have been up it. Lovely climb all the way up, challenging but not too hard.

Berger · 13 Aug 2015 at 13:10

Saytan said:
Marginal gains!

given that Laurent Fignon's ponytail once cost him the tour de france, if you're racing at a high level there's no good reason *not* to....

Those were estimates only, the difference could be less than 1w!

Roady · 13 Aug 2015 at 13:27

One More Solo said:
Yep, 3000m of climbing, the vast majority of which seemed to be in the final 100km (in terms of "proper climbs" anyway). The final climb back over the Peaks in to Leek/Macc nearly killed me. It would be a much easier ride the other way round IMO but likely to be into the wind.

My route was just shy of 200 miles so probably a bit less scenic than the one your clubmates are proposing Roady! I think the Rapha MCR-LDN ride was about that distance.

http://pages.rapha.cc/m2l

To be fair that's what they're probably doing! Timescale and distance seems right. Quite a cool 'North vs South' feature about where the finish is the next year depending on the lowest average time of riders from that denomination. The South 'won' last year so it finishes in London this year! :cool:

Berger said:
Yeah.

Let's say drivetrain losses account for 5% of your power output.

At 300w that's 15w lost through the chain, cranks, bearings etc.

Say the bearings make up 50% of that drivetrain power loss; 15w, that's 7.5w total.

If ceramic bearings are twice as good as steel ones, that's a 3.25w saving.

A quick Google gives a cost of $70 for a ceramic bearing (I guess they can be had for less) vs $6 for a steel one.

Now there are bearings in the rear hub, plus the front hub, the BB, the derailurer pulleys, say 10 all up, $60 for steel or $700 for ceramics.

So that's a cost of about $200 per watt saved.....

Yeah but as soon as the bearings in the BB are the only ones I'm looking at replacing = lower cost. They have started making noises and are probably higher than 50% of the drivetrain losses due to this, not to mention a possible increase in the lost power output.

When thinking about $140 for maybe as much as 50w lost... It becomes less 'marginal'.

Especially as I'm mostly riding at less than 300w when commuting, increasing the wear for when I'm pushing power...

To be fair I'm probably not going to feel it, just notice the noises. The whole 'something needs fixing, let's investigate what can I do to upgrade it' feeling/thoughts take over!

*shifty eyes*

If her indoors asks, I did absolutely need the Ultegra crankset to fix the problem.

Berger · 13 Aug 2015 at 13:36

You'll only be losing 50w if your bearings are made of sand and gravel. Drivetrain losses are only 3% of your total power.

The difference between ceramic and steel when new will be less than 1% of your total power output if your talking about two bearings only!

Gain more from buying a new chain every week!

http://www.cyclingpowerlab.com/DrivetrainEfficiency.aspx

Roady · 13 Aug 2015 at 13:56

But?! Noises?! Must fix!

Fantastic website for info, thanks

Brand new chains are less efficient than chains that have been run-in. The greatest efficiency gains are made in the first hour of use but gains continue throughout the first several hours of use. Don’t use a brand new chain for a key race unless you want to give up half a watt.
Cheap derailleur pulleys compared to high end equipment can cost 1 watt. Upgrades with ceramic bearings work but the marginal gain is tiny compared to the flagship offerings from Shimano and Campagnolo.
Cheap pedals with cheap bearings - technically a little higher up the power transfer chain than the drivetrain per-se - can also cost 1 watt.

So I need to upgrade my chain and pedals too. Got it!

May as well change the whole groupset, or maybe new bike?

Jonny ///M · 13 Aug 2015 at 14:01

I wouldn't bother with ceramics for the price. My bosses didn't last very long on the k force chainset.

Various people say different things and I've even been told to clean them out and run them dry.

For your giant I'd just get a shimano pf bb or something like a hope.

touch · 13 Aug 2015 at 14:05

Jonny ///M said:
Various people say different things and I've even been told to clean them out and run them dry.

I think most pro teams run their bearings (steel or ceramic) dry or with a very light oil in them because it does reduce rolling resistance. (obviously the balls rolling through a thick grease are not going to roll as well as they would through a light oil).
Not a good idea unless somebody else is paying for your replacements though!

JeffyB · 13 Aug 2015 at 15:01

Right thread this time, treated myself to some new bars, Cinelli Ram XL. Yummy

slipd · 13 Aug 2015 at 15:18

Hi guys,

I've noticed over the last couple of rides that one or two of my gears are starting to sound like they're about to come out of gear...

In the past my bike would be down the shop for a 'service' but even they're encouraging me to have a go

So how hard can it be? I've watched a few video's and read a few guides - can anyone here give me any extra pointers? I think its having the confidence more than anything.

FrenchTart · 13 Aug 2015 at 15:26

Main pointer would be - don't mess with the limit screws at all. Aside from that, start off by thoroughly cleaning your drivetrain and then re-index the rear. It's an extremely easy job. The front can be a bit more of a hassle but it's still very doable and probably one of the first things you should learn with regards to bike maintenance. Brake pads/cables being the other.

One More Solo · 13 Aug 2015 at 15:40

After a cheap-ish set of 52/36 chainrings in black. Does anyone know any deals going?

slipd · 13 Aug 2015 at 15:50

FrenchTart said:
Main pointer would be - don't mess with the limit screws at all. Aside from that, start off by thoroughly cleaning your drivetrain and then re-index the rear. It's an extremely easy job. The front can be a bit more of a hassle but it's still very doable and probably one of the first things you should learn with regards to bike maintenance. Brake pads/cables being the other.

Thanks mate! It's funny, but playing with the limit screws is usually one of the first things that comes up in all the guides... so what am I looking at first then, a quick turn on the cable adjuster on the rear mech?

FrenchTart · 13 Aug 2015 at 16:03

slipd said:
Thanks mate! It's funny, but playing with the limit screws is usually one of the first things that comes up in all the guides... so what am I looking at first then, a quick turn on the cable adjuster on the rear mech?

That's it, yeah. It's a classic mistake to change the limit screws (and to change them by a lot as at first it often seems like they're not doing anything). Just adjust the cable tension at the back and you'll be good. Most likely you just need to increase the tension ever so slightly.

uv · 13 Aug 2015 at 16:43

And clean your jockey wheels. Dirty jockey wheels make shifting horrible.

Indigo · 13 Aug 2015 at 21:16

Decided on my new wheels but need new handlebars as well (Was knocked off my bike last week) but have no idea what's decent and if I should go standard size or compact?

Currently ride a Giant Defy 3, can't say I had any issues with the bars, looking to spend upto 25-30 if anyone has any recommendations?

Saytan · 13 Aug 2015 at 21:50

IndigoGorilla said:
Decided on my new wheels but need new handlebars as well (Was knocked off my bike last week) but have no idea what's decent and if I should go standard size or compact?

Currently ride a Giant Defy 3, can't say I had any issues with the bars, looking to spend upto 25-30 if anyone has any recommendations?

it's a personal thing, go in to bike shops and feel some up on bikes.