stevage

Hi all,
So I have a Tricross Sport (lowest gear 30x34) I've taken on a few tours and find I could do with a lower granny gear. It's not a killer, but I'd like to be a little spinnier for big hills. The LBS guy said that I can go as low as a 24 tooth granny gear, though if I do that, it becomes difficult to obtain smooth shifting across the entire range. I'd be willing to reduce the biggest gear if necessary, but for the time being, I'm not planning to.

Question #1: What should I switch the granny gear to? 28, 26 or 24? The 26 is what the Surly LHT has. Is 24 ridiculous? Would 28 be enough of an improvement? I'd love to hear from people who have played around with gear ratios and what they have learnt. For info, I'm average fitness and weight, tend to go on 3-4 day midweight tours (tents but not much food), and this is southeastern Australia, so there are decent hills, but no epic mountains. I also take the bike on off-road (unloaded) rides where low gears are also useful.

To make the decision slightly easier, my girlfriend has the same bike and also probably wants to get a lower gear, but is in no hurry, so if the gear I choose doesn't work out perfectly, I'll put it on hers.

Question #2: Steel or aluminium? Steel seems like the obvious choice - lasts longer and is cheaper, right?

Question #3: How hard is it to do myself? I think I have the tools, but haven't learnt to remove cranks yet.

kayakdiver

Some around here run pretty low stuff. I can get up anything with a 26/32 and that combo gets used very little. But sure is nice when needed. Do you have a mountain bike? Or maybe you can use one from the bike shop in the equivalent gear combo to see how it feels? Might be a good way to see the difference between the 24 and 26.

Erick L

My LHT has a 26T on 26" wheels. I'd rather have a 24T but I can live with the 26. I like the 48-36-26 crank on the LHT.

It's easy to do.

Booger1

I have 20/34/46 x 14/34 with 700 wheels,not to low for my old body.I run steel granny and middle rings.They last 3-4 times as long as the best alloy rings.

Cyclebum

48/36/26 x 34 gets me and 45 lbs up long 7 percenters at 4 mph. But I'm old.

CCrew

I guess I'm really old I run MTB gearing @ 48/38/28 with an 11-32. That said, I rarely use the granny ring. 28-32 is about walking speed

Secondary tourer is 44/32/22. But that'll climb trees

cyccommute 

He's right. 24 teeth is the smallest you can go.

Changing only 2 teeth on the crank won't make enough difference to be worth the expense. In gear inches (sorry but that's how I think) here's the breakdown:

• 30/34 = 23.6
• 28/34 = 22.0
• 26/34 = 20.5
• 24/34 = 18.9

3 gear inches is significant. 4.7 gi is even more so. If a 24/34 is too low, you can always pedal in a higher gear on the cassette and keep the really low one for when you really need it.

Personally, I go for as low as I can...even if I don't use it that much. Better to have it and not need it then need it and not have it

Steel is better. Not only does it last longer, it's less likely to get a burr if your shifting style is...um...well...ugly Burrs are the leading cause of chain suckage.

It's not too hard. Look here for details.

acantor

The question of "how low to go" is a matter of personal preference. Younger and/or stronger riders can make do with higher gears. For some people, putting a lot of effort into climbing hills is experienced as pleasure or a challenge worth doing.

So here is my preference: Get the lowest, most granniest gear your bicycle can accommodate. I do not use my smallest gear every day, but I am glad to have it when I do.

My lowest gear is currently 34T (rear) - 22T (front). I wish I could go lower, but I seem to have reached the limit without paying a lot of money. But overall, I like it. My previous arrangement was 34T-24T, and an all-day climb in the Alps nearly did me in!

The Smokester

My lowest is a 26 on the front with 32 on the back. Rarely use it but...

Normally, I get by with the larger two rings.

My gearing: 46/36/26 with an 11x32 cassette.

eofelis 

My LHT has a full XT drive train: 44/36/24 with a 12x34 cassette. I have used the lowest on some steep climbs here in western Colorado. The top end is plenty as I usually just coast down the descents.

Doug64

A bunch of good advice. The only thing I would add is that the "trekking" cranks, 48/36/28 are more of a road bike crank and will usually fit the bottom bracket that is presently on the bike. For the smaller, mountain bike crank sets, 46-44/34/24-22, the bottom bracket spindle might be too long for a workable chainline. I had to go from an 110mm spindle to an 103 mm spindle when I swapped my 48/36/24 Sugino crankset (road) to a 44/32/22 (mountain). I ran into the same problem with my wife's bike, but with a Shimano crankset.

I have not had a chance to use it on a loaded tour yet, but like the other "old" guys, I think I'm going to like having the very low gear option.

Monoborracho

I run a 48/36/26 with 12-28 on my Trek 520 for road riding with an extra link in the chain. Then I put a 13-34 on the back when I tour. I run LX derailleurs front and back with barcons.

stevage

Wow, thanks for the great replies. Consensus seems to be that 26t is plenty. But...I guess I agree with cyccocommute about going "as low as I can" - I don't want to die wondering what a lower gear would have been like And it's not a big expense, if I do it myself.

So, final question: how do I find a compatible chainring? The guy in the LBS quoted a number at me (104? something like that) but I didn't quite catch it. Can't see any clear specs on the Specialized website (it says the cranks are FSA Tempo Triple but that doesn't google well). I just tried measuring the bolt distance, but am still confused - the centre-centre distance of the big ring was about 75mm, and I thought the small rings were 45mm but I could be wrong - it was hard to measure.

Steve

hockey

I have a 52,42,26 with a 34. Works great. I just swapped out the 32 for a 26. Shifts perfectly with Tiagra. This way I can still use the bike for commuting and quick rides, yet have the granny for all out uphill touring. Most of the time I ride the 42 when on tour.

quester

Nonsense, you can easily put an MTB crankset on, giving you a 22-tooth granny to go w/ that 34-tooth big cog on your cassette. At least that's what I'm running on my LHT.

And by the way, a 5.5 mile hill averaging 9-10% is in my near-term future....

Nigeyy

He was probably mentioning the BCD (Bolt Circle Diameter). The late Sheldon Brown has a great explanation of this: https://www.sheldonbrown.com/gloss_bo-z.html

Basically, when you buy a chain ring you have to do 3 things:

i. get the correct BCD for your crank arm
ii. get the correct number of bolt holes! (e.g. is your crank arm 4 or 5 bolt?)
iii. get the correct number of teeth! (from replies to your original post)

104 BCD is a common size -but Sheldon suggest measuring the distance from crank bolt to crank bolt in his web site to get the diameter more easily (see his table). To give my input on changing gears, yes, get the lowest you can as usually you will curse if you don't have a gear low enough. Steel is heavier but has more longevity -I'd say it's better for touring purposes.

However, another thing to keep in mind is that a front derailleur has a range of gears it can traverse -e.g. the usual front roadie derailleur can have problems going from a 52 big chainring to a 24 teeth small chainring. The capacities are stated in the derailleur specs, though usually you can exceed these by a couple of teeth no problem. You don't mention your biggest chainring size, just something to keep in mind.