Cassette for IMC

charris

Have read the gearing thread and a few related ones, just looking for thoughts.

 

Road bike is 50/34 and 11-25.  Tri bike is 50/34 and 12-25.  Don't have any other cassettes lying around.

 

Goal race is IMC. FTP ~250, weight ~147.314159

 

Based on the old adage mo gears is mo betta, thoughts on getting a 12-26 or 12-27?

mancona

I can't think of any reason not to get a 12-27. Like you said more gears is better and cassettes are relatively inexpensive and limited lifespan anyways.

If you don't us the 27 on race day at least you will know it was there if you needed it

Gordon Cherwoniak

Craig,

I'll be running a 50/34 with a 12-27 with an FTP of ~245 and I weigh 213 right now.  Maybe I need a triple!

I'm not familar with the course at all but Richter is 6% grade in parts (so I have heard, 11km?) and Yellow Lake (is that right) is shorter but I believe has a little more grade in places.  Mclean Creek Rd the first climb early on is steeper.  So the 26 or 27 could be useful.

Given your FTP and weight you have around 3.6 w/kg so fairly decent.  How do you fair on 6% grade, 8%? What is the grade at GWN before the turn around.  How was the 12-25 there?  I only ask because as you go to the 26 or 27 your cassette will not be a tight.  I notice right now with my FTP I have a whole around where my 80% of FTP is.  So I either have to go easier or push it, on race day when I have to use that gear (can't remember I think that's short climbs) I will have to go easier not hard.  Oh I just remember were you on your new bike at GWN, I can't remember if you had purchsed it or not.  You might have to do some field testing or look at your power file more closely from this weekend RR and next weeks rides.

So all this to say depending on how you handle the grades that we will face at IMC I may or may not change my cassette.  Also make sure you do this change sooner so that you can figure out where the hole was created in the new cassette.  You don't want to have the gap I talked about right at .7 IF causing you to spin the easier gear like a manic or grind the harder gear.

If it were me I'd probably go with more gears at least a 26 but that's more beacuse I don't know the course at all.

Gordon

Nemo Brauch

More is better :-)

Craig Watson

 Given my ride in Canada last year I highly recommend 12-27 to help you later in the run. You WILL use the 27 for a decent portion of two of the major climbs and you own't be sorry. I wouldn't ever recommend it for Florida but for Canada you will be glad you saved a few matches by not struggling so much.

The good news is when I look over my race charts as soon as you hit the peak of those nasty climbs you get 3-5 minutes each of 40+ mph coasting 

 

cdntriguy

@Craig.  I'm running the same setup 50/34 with a 12-25.  I went up the Highwood Pass with this combo and still had a gear or two left; my buddy says that climb is worse than anything you'll see at IMC.  But as Matt mentioned, I also picked up a 12-27 that I might run just in case im not "feeling it" on race day.

Coach Patrick

Great advice here....the 27 it is!

cdntriguy

After riding the race rehearsal on a somwhat hilly course (it was the only place I was sure I wouldn't get run over - Calgary 70.3 course).  You gotta go with the 27.  It's just way easier to keep gear 3/4 under control.  I forgot the difference between training watts and racing watts!

Chris G

 I heart my sram 11/26.  Best of both worlds.

Chris G

Here is one for $49.00 hard to go wrong.

 

http://www.ediscountbike.com/Casset...05725.html

William Jenks

More is better, but there is that "gear gap" thing, too. Might want to just double-check to see if either cassette combination will have one that really irritates you: http://public.tableausoftware.com/views/bikegears/CompareBicycleGearing. Far be it for me to say you shouldn't get the most gears possible; just something to look at. I did have a gear gap I didn't like on one combination I used.

cwhyte

By having a 27 you don't necessarily have more. You might actually have less where you need it the most. We also need to know what cadence you typically climb at.

I've ridden this course countless times. The only place you will need a 27 is on McClean Creek and it's pretty damn short. Richter isn't steep, the rollers aren't that steep either and Yellow Lake is even less steep. I just rode the course 2x a week ago too. Richter is a long stair-step climb and there are many places where I'm not even climbing in my 25 cassette.

I'm around 145lbs with an FTP of ~270w. I like to climb around 85rpms -- maybe a tad lower. I go with a 12-25 every time.

If you want to climb in the 90s then I'd definitely shoot for a 27.

Coach Rich

Posted By Chris Whyte on 19 Jul 2010 04:07 PM

I'm around 145lbs with an FTP of ~270w. I like to climb around 85rpms -- maybe a tad lower. I go with a 12-25 every time.

If you want to climb in the 90s then I'd definitely shoot for a 27.

 

By my math above, that's 4.1w/kg which is very, very solid in the Ironman world. It's another data point, for sure, but I think it's helpful to keep these numbers in mind when we are giving each other gearing advice. In short, Chris' speed, and cadence, will be different on these climbs than someone at a lesser w/kg.

Back in the day I used to mix cassettes, taking apart a 25-12 and a 21-11 and mixing up the cogs so that I had the gears I wanted at the speeds that I sit at most often on the flats.

Dan Socie

I rode IMC with a 11-26 (SRAM ) and I don't remember remembering wishing for more gears. But that was back when I was a svelte 150lbs with an FTP @280w.

cwhyte

But Craig is no slouch either. I realize I'm more the exception than the rule but he and I are very close in many respects. Yes, his FTP is a bit lower but not a huge difference.

Possible the most important data point that's missing is cadence though. Clearly there's a big difference between mid 70rpms vs mid 90rpms, for example.

It's a little tough to find the right "mixed" cassette on this course. Just keep in mind that this course rides very different depending on the wind. The rollers are 100% different if we have the typical headwind on the backside vs if we have no or little wind.

I've done this race 4x (05, 07, 08 and 09) and I'd say all 4 were quite different (07 being the most difficult). Yes, the safe bet is to go with the 12-27 but just realize you might have a "comfort" gap between 21 and 27. You'll use an 11 on this course most likely but it doesn't hurt much at all to give it up.

Thanks, Chris

charris

Wow - and that, folks, is why I posted here.  Lots of advice, and all of it good and thought provoking - thanks everyone!

Re: gaps - great point as those "in-betweens" can be frustrating.  From the quick research I just did, it seems like the only difference between 12-25 and 12-27 are the two big cogs (23-25 vs 24-27), and since my "gear gaps" are currently mainly in the middle, that shouldn't be a big issue - of course that depends on the exact terrain I suppose.

 

I was pretty sold on the 12-27, but that 11-26 is a very interesting (and inexpensive - nice find!) alternative.  Of course I'm not nearly as likely to spin out 50-12 as ChrisG is.

 

CoachR's "roll your own" idea is very intriguing and I definitely see the appeal.  Maybe next time though as I'm starting to overthink this a bit as is.

 

Thanks for the no slouch comment ChrisW - coming from you that's high praise.  I'm also very excited because since I'm at 145 now, I only need to drop 5 pounds and bump my FTP ~14 points to be considered a very, very solid IM rider.  On paper, anyway.

 

As for cadence, typically I aim for high 80s and I try maintain that on hills.  On hills I feel a lot more comfortable/powerful mentally at lower cadence but fear that'll chew up my legs later, so try focus on keeping the cadence up.  Maybe the 12-26 (or 11-26) would be the happy medium.  I think I need to get out a protractor and find some similar hills around here over the next month to experiment.

 

Gordon and Wayne - thanks in particular for sharing info with me as we commence final prep for IMC - greatly appreciated!

 

As an aside, I'd like to mention how hilariously old school some people are about compact cranks and "granny cassettes".  My LBS guy could barely understand why I would want a compact crank.  Asking about a 12-27 (which of course he didn't have in stock) made this quizzical look come over his face.  This is the same LBS who sold a tri bike to my friend (a bigger guy, in the LBS' defence).  When I was emailing my friend explaining why I wanted compact crank with 12-25/26/27, this is what he said:

"It's funny because that's the gearing I had on my old tri bike. In fact I had 50/34 and 12/27. But when I bought my new bike from X he convinced me to go with the standard arrangement."

 

I don't think there is any way in hell he should be riding standard, but what do I know.

 

It's seriously a huge macho thing.  Fortunately, it's also pretty macho to blow by people on the hills and mop up the rest on the run...

 

Coach Rich

Good discussion. Regarding cadence...I've been a climbing fool for a long time. Long, long, long steady climbs. As a result my default climbing cadence is about 78-82, not where I'd like to be if I were doing similar grades in a race (I'd want to be higher). So even though I may have another gear or two left I'll sit at that 78-82rpm cuz that's where I've been for so long on these climbs.

Tomorrow I'm riding down a bike flat (flat) to the beach (flat) to meet Joanne for lunch and a day at the beach between dueling dentist appointments for both of us (yeehaw). I'm very curious to see:

• The mental focus required to ride at my default effort of 85-90+% on the flats vs a climb.
• The cadence I gravitate to. I have a feeling that when I start to dial in my 85+% I'll also want to dial in <82rpm.</li>
  

Anyway, different topic but related to these thoughts of self-selected cadences on climbs, etc.