Gearing, 8sp - 9/10sp compatibility and stuff

cdaly_

So yis all have me hooked by now...

I'm riding a Giant FCR3 as my commuter (and only) bike. Doing about 27km per day with an occasional weekend spin (though I'm eyeing up the various 100k threads that pop up...). It's a hybrid (though I think somebody said it has the same frame as the Defy) with aerobars ('cos I love them) and it's running a 52/42/30 triple with an 11-32 8sp cassette.

On my commute (Baldoyle - Glasnevin) I'll typically be spinning 52/12 or 52/13 at around 70-80rpm on the Clontarf psychopath and I'll only drop down to the 42/13 for manouvering through the traffic at Fairview. If I get a tailwind, I'll be pushing 52/11 on the flat.

I tend to use the aerobars as much as possible both for aero purposes and to take pressure/weight off my wrists (and yes, I know I'm supposed to improve my core strength to take that weight off). I have brake levers on the aerobars so I only need to take a hand off them to change gear. I do have to get off the aeros to deal with junctions etc though.

So anyway, it occurred to me that I might get a bigger chainring though a 53 only gets <2% higher gearing while a 54 gets <4%. Now, most of the chainrings I can see on CRC or Wiggle are listed as 9sp while I'm running an 8sp cassette. I presume the 9sp ring is compatible with 9/10 sp chains but will it run happily with an 8sp chain? Then there's the question of compatibility. Some of the chainrings are listed as Type A or Type B with warnings about not mixing them. Others make no mention of any such thing. How do I identify what type I currently have and is it just a matter of the PCD of my crank that determines which chainring I can fit?

Then the other thing... Y'all keep going on about how drops are the only way to go so I thought of investigating. Looks like a minimum of GBP150 with room to spend 2 or 3 times that amount and that ain't going to happen without trying something out first. Do ya reckon the LBS would lend me a set of drops, shifters and levers to try out? And would they expect me to buy from them if I liked the setup? What sort of money would I expect to pay the LBS? Now, when I go looking at shifter/lever sets, they are pretty much all 9 or 10sp with maybe one 8sp lever to be had. Again, I'm running an 8sp cassette, can I use a 9sp shifter and just ignore position 9 or is it that the indexing points are different?

The bike appears to have a Shimano Sora drivetrain which seems to be not among the expensive stuff but is serving adequately for my needs. And no, a bike upgrade is not on the cards. I've been riding this bike for a year now (about 2 months before the BTW scheme was announced! ) and am well happy with it. It represents a serious upgrade on my previous bike and I won't have funds for another for some years to come...

DirkVoodoo

What are you on and where can I get some?

That is some impressive commuting!

I don't think a shop will "lend" you a conversion, it takes some labour and the cost would probably be better off spent on renting a road bike from somewhere or simply asking to take one for a spin.

8 speed shifters, a set of drop bars...shouldn't be that expensive to buy the parts. Not sure how much though.

I would say that trying to maintain a higher cadence would be more beneficial than buying larger chainrings. Sitting nicely at 90-100 rpm

At your 80 rpm cadence you are pumping out 48.6 km/hr on the flat (wow!) in 52/11. Get that up to 90 rpm and you are straight up to 54 km/hr. I have only ever seen one other person do this kind of speed solo on the flat and his name was Blorg!

cdaly_

I'd hardly be pushing 80 rpm on 52/11! Prolly 70 or less with a tailwind. I seem to manage 70-75 on 52/13 fairly regularly though. Last time I had a working computer, I was achieving 35-38 km/hr at times (which works out at 70-75rpm on 52/13) and averaging about 25 km/hr on the 14k commute.

I tend to be unable to do less than flat-out and it's well possible, given I've been doing this run for a full year already, that I've already got to my level of fitness already and higher gearing wouldn't do anything for me...

Or I could be lying over-estimating my abilities...

Lumen

Cadence is your problem, not gearing.

52/11 is enough for about 60kph at 100rpm (a normal cadence for pushing on).

Fabian Cancellara won this years world time time championships with an average of 51.58 km/h for almost an hour.

Maybe you can lend him your hybrid for next year

cdaly_

cdaly_ wrote:

at around 70-80rpm

Ok, so that would be 'Angler's Cadence' then...

I did a bit of timing this morning and came out with 70-72 rpm tops on the flat in 52/13 which comes out at about 37 km/h. That would have been pushing it just a little for about 60 sec at a time. In between it would have been about 68 rpm for the 12 mins from Baldoyle road to Fairview (or something)...

Lumen wrote:

Maybe you can lend him your hybrid for next year

Gerrof! He can buy his own...

BTW, any thoughts on the 9sp shifters with an 8sp cassette? Is that just totally wrong?

short circuit

I feel so inadequate .... I think its time I start responding to those junk e-mails which promise eternal good performance which lands in my mail box ....

Been on the bike 18 months now ... and I still don't know how it feels to be on the 11 cog ...

cdaly ... good one ... have you thought of taking up racing next year ...

For compatibility, I think you can run 9 speed rings on an 8 speed bike and you will be fine ... not based on experience, but was told so in a bike shop.

The conversion to drops will be expensive ... more than a bike equipped with sora or your capability deserves. And aero bars are more aero than drops .... and you won't need too many hand positions on a 14km commute.

trad

52X13 seem awful high for commuting. I used to commute 14 miles e/w to work in the late 80's and the highest I used was 52X15 on downhill section of N11 into Stillorgan and was fit enough at the time to do maracycle / wicklow 200 etc. A lot of the time I used 42X15.

Maybe you should concentrate on cadence rather that gearing. Are you a good climber?

rob1891

cdaly_ wrote: »

BTW, any thoughts on the 9sp shifters with an 8sp cassette? Is that just totally wrong?

Check the section titled "Alternative Cable Routing" on this page:

http://www.sheldonbrown.com/derailer-adjustment.html

Does exactly what you are looking for, 9 speed shifters on 8 speed cassette. You can get the remaining life from your 8-speed drive train before upgrading to a 9-speed cassette/chain.

cdaly_

short circuit wrote: »

Been on the bike 18 months now ... and I still don't know how it feels to be on the 11 cog ...

The aerobars make up a significant increase in my speed (which translates to higher gearing (or should that be cadence)).

short circuit wrote: »

have you thought of taking up racing next year ...

Jeez no. I have kids!




Kids => no time...

short circuit wrote: »

The conversion to drops will be expensive ... more than a bike equipped with sora or your capability deserves. And aero bars are more aero than drops .... and you won't need too many hand positions on a 14km commute.

Given that I DIY everything, the drops conversion would be cost of parts only. If I stayed with sora gear, I could do it for about GBP150. Of course I'd be keeping the aero bars 'cos I love them...

rob1891 wrote: »

upgrading to a 9-speed cassette/chain.

I presume that requires upgrading the chainrings also. Would the existing derraileurs cope with the narrower chain?

rob1891

If your 8 speed chain rings are not worn out by the time you switch to 9-speed, then I think you could keep them. The difference between 8 and 9 speed cog widths is only 0.02mm!

cdaly_

Lumen wrote:

Cadence is your problem, not gearing.

So, if I want to work on cadence, should I be going 1 gear lower than my habitual and just pedalling faster?

Or maybe I should head over to the Ladies Lounge for some advice...

Lumen

cdaly_ wrote: »

So, if I want to work on cadence, should I be going 1 gear lower than my habitual and just pedalling faster?

Or maybe I should head over to the Ladies Lounge for some advice...

If you don't have a bike computer with cadence, either count the pedal revolutions or work out the speed/gear combinations using this, print them out and tape them to your stem.

I'd normally aim for 90-100rpm, except in special circumstances (e.g. hills, time trials).

Obviously if you're training for something specific you might want to choose non-optimal cadences, but it sounds like your current problem is not enough spinning.

Also, make sure your saddle is at the correct height. High rpm may uncover smoothness issues (e.g. rocking hips) which can be corrected by saddle height adjustments. If you need to change saddle height, do it gradually.

cdaly_

Errm, so, um...

It turns out I'm riding 52/15 @72rpm as my normal gear for a speed of about 32km/h.

I still get onto the 52/13 when pushing hard but I guess I'm not quite as Chuck Norris as I thought...

52/11 @ 65 (or 70)rpm in a tailwind still stands though.

Lumen wrote: »

Also, make sure your saddle is at the correct height. High rpm may uncover smoothness issues (e.g. rocking hips) which can be corrected by saddle height adjustments. If you need to change saddle height, do it gradually.

Current saddle height is heels can rest on pedals at full knee extension (slightly bent with ball of foot on pedal). That's a bit higher than it used to be. I'm not feeling any rocking issues there.

DirkVoodoo

cdaly_ wrote: »

I still get onto the 52/13 when pushing hard but I guess I'm not quite as Chuck Norris as I thought...

Better remove the submachine guns from your handlebars so.

32 km/hr is still an impressive commuting speed, but I did think your gearing was getting close to pro standards and had my doubts. A higher cadence will not only benefit your cycling, but your knees will thank you for it as well. Grinding a big gear often feels like you are doing more work, but as the calculations show, spinning a smaller gear can allow you to go faster with less stress on your joints. Of course, you still need the aerobic capacity to keep your muscles oxygenated and remove waste products.

cdaly_

you still need the aerobic capacity

/me converts belly to lungs and lungs to belly for a 50% lung capacity increase...

cdaly_

So I dropped one gear and did the run home on 52/17. Timed cadence at 80 rpm on the Clontarf psychopath and tried to maintain that all the way. Seriously hot by the end and barely able to walk. I'll try keeping that cadence up for the week and see what happens.

If anyone happens by me collapsed by the roadside you might just stop and say "Chuck Norris could do it"...

Definately felt faster this morning tho...