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Transcontinental gearing

by terrycojones
Sat, Dec 17, 2016 15:27
14

Hi. I'm hoping to be accepted into TCR#5 next year and have been thinking a lot about gearing options. But I don't know much about bike mechanics, options, compatibility, etc., so I thought I'd ask for advice here.

I'd like Di2, based on the many reports of hand pain problems. I'd also like to have very low gearing options, because I'll be dragging perhaps 10kg of extra weight (including food & water) up long climbs, and I'd like to main a relatively high cadence (e.g., not below 70, preferably 80). I don't want to underestimate the need for low gearing. Doing 250+km/day for 2 weeks straight, in mountains, with bags, is probably going to result in extreme fatigue.

I'd also like whatever gear I buy to be as useful as possible in the future.

My current thinking is to buy a bike (let's assume I get a new bike, for simplicity) with Ultegra Di2, compact (50-34) or sub-compact (52-36) chainrings, and an 11-32 cassette. Then, swap out the crankset for a 46-30 to use in the TCR. I guess I'd need a chain spotter for the FD, perhaps like this. Once the TCR is done, I can put the compact back on and live happily ever after with Di2 and regular road bike gearing.

Based on reading and some calculations, I'm estimating (hoping!) the low 30x32 combination this setup would allow me to get up whatever I need to.

My main question is what 46-30 crankset would be compatible. E.g., this FSA option looks nice, but I don't know enough about bottom bracket standards to know concretely what it would work with. I can see other options on the web, but I feel quite in the dark as to what will work.

Questions.... Does this sound like a good approach? Will it work? What other gearing options might be worth considering? I've also read that Di2 can be made to work with an 11-40 cassette via the use of a derailleur hanger like this, so that might be an option (with a compact up front).

I've kept the questions above focused just on gearing, but I'd also be very happy to hear opinions about bike options too. I've looked at a bunch, of course. But maybe that should be a topic for another posting.

Thanks for any help / thoughts. It might sound from the above like I know what I'm talking about, but I really don't. So I could easily be overlooking very basic & obvious things. I'm very much a novice on bike componentry.

Terry

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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14 comments

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ktache | 7 years ago
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CXR94Di2, I applaud your obsession and eye for detail.

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pockstone | 7 years ago
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This link:

http://ridefar.info/bike/components/ratios/

gives a pretty comprehensive  overview of gearing issues, from someone who's done the TCR. I recall another blog from a Swiss based rider ( I thought it was Chris White but can't seem to find it) that gave very good arguments for a super compact chainset on the TCR. The main gist of the argument was that there's no point in churning a 50 (or bigger) x 11 downhill when you'll be wasting energy overcoming air resistance. Better coast downhill and enjoy the rest, Good luck!

 

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terrycojones replied to pockstone | 7 years ago
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pockstone wrote:

This link:

http://ridefar.info/bike/components/ratios/

gives a pretty comprehensive  overview of gearing issues, from someone who's done the TCR. I recall another blog from a Swiss based rider ( I thought it was Chris White but can't seem to find it) that gave very good arguments for a super compact chainset on the TCR. The main gist of the argument was that there's no point in churning a 50 (or bigger) x 11 downhill when you'll be wasting energy overcoming air resistance. Better coast downhill and enjoy the rest, Good luck!

Hi pockstone. Yes, Chris' pages are fantastic, thanks. That's where most of my knowledge comes from 1 I'm probably going to try to replicate his compact + 11-40 setup, possibly including swapping the first 4 small cassette rings for those on a Shimano 14-28 junior. But I also wanted to gather other opinions.   The Shimano XT Deore Di2 2x11 also looks like an interesting way to go.

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mearle | 7 years ago
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Have a look at the new micro-compact from Praxis Works allowing 48-32.

https://www.praxiscycles.com/product/alba-m30/

http://www.roadbikereview.com/reviews/new-praxis-works-zayante-and-alba-...

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terrycojones replied to mearle | 7 years ago
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mearle wrote:

Have a look at the new micro-compact from Praxis Works allowing 48-32.

Hi mearle. Thanks - that looks nice. It's pretty close to a 50-34. Maybe I could couple it with a less extreme cassette (e.g., an 11-36).

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CXR94Di2 | 7 years ago
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Yes you are right road Di2 does work with 11-40T cassette married to 50/34 crank   3

 

See here, I set it up on my turbo with custom made hanger, standard length chain, XTR cassette.

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terrycojones replied to CXR94Di2 | 7 years ago
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CXR94Di2 wrote:

Yes you are right road Di2 does work with 11-40T cassette married to 50/34 crank   3

See here, I set it up on my turbo with custom made hanger, standard length chain, XTR cassette.

Hey! Thanks 1  This is what I've also heard can be made to work. It's nice to actually see it. Did you machine the hanger yourself? I'm told it can be made to work via something like this: http://www.wolftoothcomponents.com/products/roadlink

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CXR94Di2 replied to terrycojones | 7 years ago
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terrycojones wrote:

CXR94Di2 wrote:

Yes you are right road Di2 does work with 11-40T cassette married to 50/34 crank   3

See here, I set it up on my turbo with custom made hanger, standard length chain, XTR cassette.

Hey! Thanks 1  This is what I've also heard can be made to work. It's nice to actually see it. Did you machine the hanger yourself? I'm told it can be made to work via something like this: http://www.wolftoothcomponents.com/products/roadlink

I did machine the hanger myself initially, having about 10mm longer and 5mm rear offset. I then had a laser scanning/ cnc company make me some in bling anodised red,tidying up my prototype(silly money), but hey ho

Those wolf hanger extenders weren't about when I did my hanger. They arrived on the scene a few months later

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therevokid | 7 years ago
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if running di2 you could also consider the xtr mechs ....

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StraelGuy | 7 years ago
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A triple's a great idea. Assuming the bike came with a Shimano bottom bracket, that FSA chainset wouldn't work. Shimano axles are 24mm, FSA use 30mm. Something like this maybe?

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terrycojones replied to StraelGuy | 7 years ago
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guyrwood wrote:

A triple's a great idea. Assuming the bike came with a Shimano bottom bracket, that FSA chainset wouldn't work. Shimano axles are 24mm, FSA use 30mm. Something like this maybe?

Thanks. The cranks you linked to have a 36T larger small chainring, which is already bigger than a compact. (I do like the 46T larger chainring, which is why I'm interested in a 46-30.) Thanks for the axle numbers too!

 

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Griff500 | 7 years ago
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...or, do what Tandem riders do to solve much the same problem: A triple up front. Loads of range and without sacrificing close spacing. Cannondale for example use 52/39/30 rings with a 12-30 cassette.

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Griff500 | 7 years ago
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The rear hangar looks interesting at first sight, however for me, Wolftooth have blown their credibility by printing incorrect data on their site. They state that the total capacity of the 11 speed Ultegra SS and GS are 28t and 37t respectively. If this were true, those ubiquitous compact 11-28 setups, most of which come with short cage, would be outwith Shimano recommendations. Shimano however, specify the capacity as 33t and 39t respectively.

On the assumption that this is a genuine mistake, I have dropped a mail to Wolftooth, however as this is their core business, it is an unforgiveable mistake to make. 

More importantly, Wolftooth state that their device does not expand the range of the derailleur, so your propsed setup wouldn't work. All this device does is allow bigger sprockets on the cassette, but not a bigger range. Your 11-40 cassette, with 50-34 up front, would require a capacity of 45, versus the GS cage capacity of 39. 

Sounds like it's not what you want.

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terrycojones replied to Griff500 | 7 years ago
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@Griff500

Thanks for the replies! I've also thought about a triple... But I had the impression that that would rule out Di2.

 

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