gear range dumb question

DonutDad

I've been a mountain biker for years, and as such used to a triple chain set and a wide gear range.
I always rode with the following consideration for chain wear/efficiency etc.
I always figured I could use any rear gear if I was in the middle ring at the front
I limited use of small chain ring to the lowest 2 or 3 gears at the back
I limited use of big chainring to the highest 2 or 3 gears at the back.

So, now I'm using a 34/50 with 9 speed at the back (not sure what sizes, but standard I guess), what similar precautions, if any, do I need to take?

Do I need to be concerned about chain line, or is it negligible on a road bike with this set up? I find myself using the whole block in the smaller 34T ring, and spinning out very easily on good ground, so switching up to the 50T and automatically just using the highest couple of gears at the back, but I'm finding myself wishing I could use more of the block in the big ring, is this considered OK ?
If it was ok to use say, the highest 4 or 5 gears in the big ring, I'd probably be ok.
Any thoughts ?


Feels like a really stoopid question. I know I could go ahead and do whatever I like, but it makes sense to consider mechanical efficiency, wear and tear etc., and I find myself doing it out of habit from using the much wider gear range on my mtb.

wishitwasallflat

Avoid the last two extremes - i.e. in 34 ring don't use two smallest sprockets - in 50 don't use largest two - avoids extremes of chain line and preserves life of drivetrain without losing any signifcant part of range as overlaps are available to get same ratios.

Mike39496

I run a 34/50 and a 9 speed cassette. On the big chainring I tend to avoid the 2 largest gears on the back and on the small one I tend to avoid the 2 smallest. Try it out though, you'll hear it grinding if it's wearing.

ForumNewbie

DonutDad wrote:

I've been a mountain biker for years, and as such used to a triple chain set and a wide gear range.
I always rode with the following consideration for chain wear/efficiency etc.
I always figured I could use any rear gear if I was in the middle ring at the front
I limited use of small chain ring to the lowest 2 or 3 gears at the back
I limited use of big chainring to the highest 2 or 3 gears at the back.

So, now I'm using a 34/50 with 9 speed at the back (not sure what sizes, but standard I guess), what similar precautions, if any, do I need to take?

Do I need to be concerned about chain line, or is it negligible on a road bike with this set up? I find myself using the whole block in the smaller 34T ring, and spinning out very easily on good ground, so switching up to the 50T and automatically just using the highest couple of gears at the back, but I'm finding myself wishing I could use more of the block in the big ring, is this considered OK ?
If it was ok to use say, the highest 4 or 5 gears in the big ring, I'd probably be ok.
Any thoughts ?


Feels like a really stoopid question. I know I could go ahead and do whatever I like, but it makes sense to consider mechanical efficiency, wear and tear etc., and I find myself doing it out of habit from using the much wider gear range on my mtb.

I've just recently bought a bike with a 50/34 compact as well after always using triples. Seems strange that you are only using the 2 highest gears at the back when in the big ring. I tend to move up to the big ring ring when I get higher than the middle at the back and then move down again at the front when I have moved back down to the middle or below at back. As the others have said you shouldn't use the extremes at either end - you will probably feel the chain rubbing the front mech if you do. The difference about a compact is the big drop from 50 to 34 at the front, which means that when you drop down, you can tend to spin a bit, so sometimes you need to quickly move up a couple at the back. If you are on a triple dropping from say 48 to the middle ring of say 38, you don't tend to spin as much.

DonutDad

thanks folks that all makes sense, it's good to get clarification. Although the same extremes of chain line won't exist on my road bike as my mtb, I wasn't sure if it was still significant enough to be an issue - old (bad) habits die hard, it felt wrong but I didn't just want to go making it up and everyone is so helpful on here so no harm asking. A little more play with when to jump from little to big ring and I'll have it sorted.

cheers.

wishitwasallflat

Enter the details here and you can see the ratios and get an idea of when to change to keep steady cadence but it's really feel that will get you there

http://www.machars.net/bikecalc.htm