I'm thinking of giving my 54 year old legs a little break
 

No, not that kind of "break"

How much difference, really, would it make going from a 26T in the rear to a 27T?
For that matter, why does Shimano say their 105 RD can handle 37 or less teeth, total capacity but a maximum of 27 teeth. What does "Total capacity" mean?

I'm guessing this ain't worth the bother

http://sheldonbrown.com/gears/

http://sheldonbrown.com/gloss_ca-g.html#capacity

Can't remember what Gearing you have overall. Compact or triple. And 10 speed or 9.

The rear derailler- there are two types. A short and a long. the normal to be fitted for a road bike would be a short. This can only handle so much Chain slack and will manage a 12 to 27. Mountain bikes would have a long reach fitted and this can handle more chain slack. Perhaps the wrong term but this is the easiest way to compare it.

As to the 26 to 27 t. One T would not make a great deal of difference but if you are on the limit of what you can take- It is worth it. On the Giant I have a triple of 52/42/30. Standard 8 spd rear cassette of 12/26 and for Ventoux- I fitted a 28. I had to shorten the chain by a link to be able to get the 30/28 and that was the gear I wanted. Caused a problem in that I could not get 52/28 as the chain was too short- but I should never be in that gear and I definitely did not need it.

Remind me of the gearing you have on your bike- and I'll try to answer- or others will come back with the technical solution.


The Boreas has A compact of 50/34 and 12/27 r cassette. This in theory is the lowest gearing I can get with 10 speed but I could change the crankset to a triple but that would after a lot of expense(New F Derailler aswell) only give me a lowest gear of 30/27. What I can do is get a 10 spd Cassette from a few specialist suppliers- and the quality is not supposed to be that good- and that cassette is 11/34. It will require a long reach R. Derrailler aswell but I have plenty of those from the MTB's.

There are so many options for fitting lower gearing- MTB cranksets- MTB deraillers and cassettes and I believe thers are 10spd 29t cassettes made by someone- But I have no experience of them.

SKT, the rear derailleur spec is double edged. One spec is the number of teeth on the cassette that the derailleur can cover while moving sideways while shifting (27 in this case). The second spec is the chain wrap that the derailleur can handle (this one is the sum of the differences between the smallest/largest cassette tooth count and the smallest/largest chainring tooth count. or 37 in this case.)

The example given here is 12/27 rear for 15 teeth with a max largest of 27 (ok)
and 22 more teeth available for the chainrings (could handle a 30/40/52 triple)

Thanks guys! This is great stuff. Of course when I read the explanation of max capacity, it all made instant sense. I mean, all that slack chain has to be taken up somewhere, right? And I always forget about Sheldon Brown's site; I need to book mark that.

OK, details: Front triple=52/42/30. Cassette= 12-26. 22+14=36. Good there.
Postulated 12-27=37. Good there, too. Just.

I still wonder if 1 tooth makes that much diff?
I could always calculate out the gear inches and see.
Or change the sprocket and REALLY see.

Shimano ratings are a couple of teeth conservative.

Hm... so, in theory, I could slap a 28 on there? Maybe more?

yup. Even bike manufacturers will use a 28 sometimes on 8 speed setups. The older Sora equipped Trek 1000 was a prime example with an 11/28 in the rear.

Did I miss something here? You seem to say that you had to shorten your chain to accomodate a larger cog on the rear cassette. I can see why you might need to add a link, but why would you remove one?

You should be able to use a 28-tooth cog. I swapped out a 12-24 (8-speed) cassette for an 11-28. Did not change dérailleur or chain length. There is a noticeable difference between the 24 and the 28 on the steeper hills. The 11-tooth cog was a little small for me, so I replaced the 11-tooth cog on the new cassette with the 12-tooth cog from the old cassette, and it works fine. I'm guessing you would notice some difference between the 26 and a 28.

You could always slap a long cage MTB derailer on there and change your cassette to an 11-32 or 11-34. Not everyone has the knees of a 22 year old.;)

Doesn't he also have the option of going with a smaller crankset? For example, a 48/36/26 on the front.

Wouldn't be very traditional for a LeMond/road bike.

As to using a MTB rear derailleur and cassette, like say a Deore XT rd and an 11-32 cassette, I didn't think those worked with brifters. Am I wrong?

Rear works fine. Front can't mix.

Disclaimer: I go by my gut.

Why not just keep using what you have, gutting it out , until you reach the point where you no longer entertain these kinds of questions?

Unless you ride every time with the twins, Pain and Suffering, why else are you thinking of changing?

+ 1...

So those darn $@#$@#% brifters do work with MTB rear derailleurs, eh? I've been told they don't by a couple of people.

If this were a big priority, and you wouldn't mind giving up 1 tooth shifts on the road, I'd seriously think about swapping out the 105 for an XT derailleur and an 11-32 cassette. Many of the higher quality hybrids go this way specifically for the easier hill climbing. Combined with a 48/36/26 crank, they have 3-4 gears lower than SKT's lowest gear.

How much do you actually use your lowest gear?

I pretty much use my lowest gear up any climb over 6% or so if it goes on for more than, say, 1/4 mile
Around here, that's pretty often.

I don't really want to put a MTB derailleur on my LeMond.

And, as for gutting it out, that's pretty much where I'm at now.
Yeah, it works and I do this a lot better than I did even 6 months ago but I wonder how much good it's doing my knees. I don't feel any real pain but I'm loading 'em up pretty good. If a couple of extra teeth will help me lighten that load and let me go farther, I'm willing to consider it.

Besides, I like to tinker. I need more tools :D

I would prefer to go with smaller chainrings than a wide-range cassette. 50/40/28 up front with a SRAM 11-26 cassette would give you a range of around 29 to 122 gear inches, and still leave you some reasonably close ratios for pacelining on group rides. You could probably keep your front and rear derailleurs, although you will probably need to lower the FD a bit.

Oh, the site is back... boy is it ever unstable these days.

Looks like the 28T cog is out. Can't be done with a SRAM 950.
I'm just gonna have to keep at it and build myself up

Your KaiTai has traditional hybrid gearing of 48/38/28 w/11-32. How is it on hills?

+1

I've been here and done this. I started with a compact 50/34 with 11-26 cog. I'd just started cycling and living in Hilly SE PA and needed a lot of help with hills. My LBS put a MTB style 11-32 cog on the back which with the long cage rear dérailleur I had was not a problem for chain length or the "range" of an 11-32 cassette. 50-32 was a bit of a reach, but not a gear combo one would normally use anyway.

After ~5 months I started riding my normal commute and weekend rides without using my granniest gear of 34-32 and just stayed in the second most of 34-28. I found I could handle all hills with only a bit of extra effort. Now I decided to put my original 11-26 cassette back on and repeat my normal riding routine. Again I found I could handle all the hills, but again more effort was required and I am left wondering how I would handle an extended hill climb of a mile or so without a touring style granny gear combo like 34-32...

But to get to the point, the difference between 26 and 27 is so small that I doubt it is worth it and that you will find that just gutting it through will work fine for you. 26 versus 32 - now that is a difference you will notice, but may require chain and/or rear dérailleur changes, Note too, that going to a 11-32 cog will effect the stepping of the gears and they will be more of a "jump" as you work your way up the range. Not a big deal, but can be annoying if you are searching for the perfect gear combo to match your cadence and riding conditions.

BTW, for my new bike I'm looking to split the difference and go with a SRAM 11-28 10 speed cassette

Sheldon Brown addresses this issue on one of his pages (of course). He makes note that one can replace their inner chain ring with a smaller one, even one smaller than the derailleur's specifications, as long as one does not attempt to use the small ring with small cogs in the back.

That is, you could replace your 30t ring with say a 26t and as long as you don't attempt to use it with a 12t or 13t cog, you should be fine.

http://sheldonbrown.com/harris/chainrings/74.html

With your Reno spec'd as having everything Shimano except the cassette, you should be able to put a Shimano cassette on and ride off happily. They make an 11-28 cassette. Check Sheldon Brown's Harris Cyclery, or your LBS should be able to get one for you.
The suggestions to put a smaller little ring up front are also a possibility, I put a 26 on my recumbent, and it works. The chain rides on the bottom of the derailer cage unless the chain is under load, then there's no contact. The drop from my 42 middle ring was also causing it to drop off the little ring while downshifting, but I put on an "N Gear Jump Stop" and solved that.

Dumb question: I can swap out the SRAM 11-26 with a Shimano 11-28 and not have to change the hub? They're interchangeable? That would be nice.

As for my Kaitai... I can't answer that. I haven't been able to ride it for a couple of months now so I don't know how it feels to climb on it anymore. I know I'm stronger than I was the last time I rode it so I'm really curious to see what it's like. Maybe in another 2 or 3 weeks. I hope.

Yes, the Shimano SRAM 8, 9 and 10 speed hubs and cassettes are interchangeable with the exception of some of the newest Shimano Hubs that have deeper splines for 10 speed.