Advice re gearing options

Hatcho

Hi all,

Couple of years ago I bought a Lapierre Audacio 400 Triple - I went for the triple as coming from MTB I reckoned (correctly) the granny ring would help on the climbs.

Still loving the bike and it's only shortfall is that since I've become a stronger cyclist I find the top gear isn't tall enough. On downhills I'm chasing the wheels with my feet only to watch others cruise by with a nice slow cadence due to having taller gearing.

The current crankset is 30x39x50 and cassette is 13x25 9-speed Tiagra. So what are my options - change the cassette or fit a larger chainring up front? Bit new to all this so any and all help/advice is greatly appreciated!

So far have spotted an 11x25 cassette on CRC for not much money. Would give me 2 less teeth on the back compared to the current setup.

Cheers,
Hatcho

cdaly_

The 11x25 cassette will make a big difference to your top gear and definitely cheaper than a new chainset. The other thing is to pedal faster or gain a bit of weight and let gravity help...

Hatcho

Lol - at least some of the point of my cycling is to lose weight so thats option's out the window! Pedalling faster is also a no go as the legs are already a blur.

So new cassette time it sounds like...and new tools too!

smacl

Cassette is the way to go alright. Move from 13 to 11 represents an 18% change in gain ratio, whereas moving from 50 to 53 would only give you 6%. Also much cheaper and easier to fit.

Hatcho

Thanks for the advice folks. Cassette I listed above is ordered and on the way!

One other quick question - when looking at the cranksets available on CRC I noticed they are specifically 8-speed or 9-speed or 10speed. How come the number of ratios on the rear of the bike influences the type of front crank needed?

smacl

Chains get narrower as you have more gears in the cassette, so I'm guessing width and/or spacing between front gear wheels will also be narrower. Changing a 50/39/30 triple to something with a 53t large ring could be a pain, as your choices are a 53/39 standard double which leaves you with far fewer low gears, or 52/39/30 triple which are less common / more expensive (e.g. Ultegra).

C3PO

I think I'd go with an 11-23 cassette if you're going to change anyway - the closer ratios would be nicer and you hardly need the 25 cog with a triple?

smacl

C3PO wrote: »

I think I'd go with an 11-23 cassette if you're going to change anyway - the closer ratios would be nicer and you hardly need the 25 cog with a triple?

The difference between the granny ring on a triple and middle ring on a compact is less than you might think. I had 11-23 on my triple and found it a bit of a grunt on very steep inclines and long hilly days. 30/23 on a triple corresponds to 34/26 on a compact (2.6 gain ratio). I now have 13/28 on the back which I find great in combination with 53/42/30 up front, and leave the 11/23 on my turbo wheel.

C3PO

smacl wrote: »

The difference between the granny ring on a triple and middle ring on a compact is less than you might think. I had 11-23 on my triple and found it a bit of a grunt on very steep inclines and long hilly days. 30/23 on a triple corresponds to 34/26 on a compact (2.6 gain ratio). I now have 13/28 on the back which I find great in combination with 53/42/30 up front, and leave the 11/23 on my turbo wheel.

Fair enough - I should have stuck it into my handy "gearing app" before posting! Having said that I find a 34/25 is as much as I ever need and I'm a fairly big guy and ride Wicklow hills all the time but I take your point - it's always nice to have a "bail out" gear!

smacl

C3PO wrote: »

Fair enough - I should have stuck it into my handy "gearing app" before posting! Having said that I find a 34/25 is as much as I ever need and I'm a fairly big guy and ride Wicklow hills all the time but I take your point - it's always nice to have a "bail out" gear!

I'm doubtless a bit of a wimp on the bike, but I find I use 30/28 quite often. Notably around Wicklow on the wall and other such ramps. I've been up them all in 30/23 as well, and once got stuck going up the wall in 42/28, but was coughing up bits of lung by the time I got to the top. I'll leave all that unnecessary suffering to the younger generation, character building I'm sure!

I'm seeing a lot of 11/32 cassettes on offer these days (e.g. standard with Canyon Roadlite 6), which is properly gappy. The cynic in me reckons its a solution for people that don't want to be seen with a triple, but want the lowest possible gearing anyway.

Hatcho

Just did a bit of research into the difference between the double and triple chainsets for my 2010 bike and they actually vary less than I had thought.

The lowest possible gear ratio on the double is 1.214 and on the triple is 1.200 giving only a 1.167% difference.

The highest possible gear ratio on the double is 4.167 and on the triple is 3.846 giving an 8.346% difference.

So things aren't that much easier on the uphills with the triple but your cadence will be a good bit higher on the descents.

I've ordered the 11x25 cassette as that'll still give me the same low gear ratio as I'm used to (I'm lazy on the hills! :P) but will reduce my downhill cadence by 18% as pointed out by smacl in an earlier post.

Thanks again for the help and advice folks - much appreciated!