question about changing chainrings

[brightgarden]

I have Shimano 105 triple on my road bike and have to change the chain (stretched 1/16"). When I inspected my chainring and cogs, found that the middle chainring was worn more than just a bit. I suspected the problem originally because the chain "rattles" when I put it into the big ring (which I rarely do). The big and little rings are barely worn because I rarely use them. The cogs appear fine.

So, I've got my new chain, and am about to order the middle chainring and later go to my buddy's house to change it (he has bike stand and tools).

Now, I'm about to do a very hilly century in about 6 weeks, and wonder if it is reasonable with to put a smaller granny ring on (replace the 30t with a smaller ring). The current 30t is ok, but it is not low enough to help on the really bad hills, which is why I rarely use it. This is a pie in the sky idea right now, so if it is just plain nutty or even impossible, let me know...

At this point, if it is even possible, I'd like some input on where I can find a compatible smaller ring (maybe 26t?).

Thanks!

 

[KGnagey]

What size middle ring did you buy?

You may be able to go smaller in the granny, but too much difference between the granny and the middle ring, (or the middle and big chain ring), may cause some hesitation on the up shift. Also a large difference may cause the chain to actually jump over the gear when you are trying to down shift. If you currently have a 30 on the granny going to a 28 shouldn't make too big of a difference. It will be more noticable on a 26, depending on your middle ring size. You may want to think about changing the rear cassette that has a larger range. If you a runnig a 12-23 try a 12-26. It never hurts to change the rear cassette when installing a new chain. I say just keep the 30 and push your self up those hills, this ride will give you the chance to use that 30.

good luck.

 

[KGnagey]

I should also add that if your middle ring was worn so bad, that your rear cassette has a few worn gears as well. You'll know when you put the new chain on and if it slips under load, change the cassette. The tops of the gears should be flat, not pointed. The gear should be a uniform U shape and not look like a NIKE swoosh.

 

[brightgarden]

More info:

my rear is 12-25. cogs are fine. i thought that was weird. talked to a mech who said sometimes the chainring does wear out faster, especially if i am mostly in the larger cogs. he suggested i change the middle because it was so MUCH more worn out than the other chainrings (he also told me to do more sprints to get into the big ring more often and do more intervals on hills to get in the granny gear more often). but then, we were chatting a lot and maybe it was just more stuff to say to prolong the conversation...

the triple is 52/42/30 right now. i was just explaining to a friend that the 30 is ok on moderate hills, but i can't maintain any kind of cadence on really steep hills, and it only takes a couple to just blow my energy reserves. i believe it WILL make me stronger to stay with the 30, but given what i'm looking forward to, i thought it may be wiser to do a century using something that'll get me up the 1-2 mile 3-4% grade climb right in the middle of the ride. i'll probably stay with the 30 just because i don't want to screw around with something if it's dubious. but if others think it's reasonable, i might try it just for the short term until i build up my strength more for these climbs.

[i'm a weakling yet...]

 

[boudreaux]

Originally posted by brightgarden
More info:

my rear is 12-25. cogs are fine.

the triple is 52/42/30 right now. i thought it may be wiser to do a century using something that'll get me up the 1-2 mile 3-4% grade climb right in the middle of the ride.

No doubt training header helps alot,and so does not dragging around excess bacon. People use 26 and 28 grannys with that setup,and it usually shifts ok.A 27 big cog is also an option.

 

[daveornee]

Originally posted by brightgarden
I have Shimano 105 triple on my road bike and have to change the chain (stretched 1/16"). When I inspected my chainring and cogs, found that the middle chainring was worn more than just a bit. I suspected the problem originally because the chain "rattles" when I put it into the big ring (which I rarely do). The big and little rings are barely worn because I rarely use them. The cogs appear fine.

So, I've got my new chain, and am about to order the middle chainring and later go to my buddy's house to change it (he has bike stand and tools).

Now, I'm about to do a very hilly century in about 6 weeks, and wonder if it is reasonable with to put a smaller granny ring on (replace the 30t with a smaller ring). The current 30t is ok, but it is not low enough to help on the really bad hills, which is why I rarely use it. This is a pie in the sky idea right now, so if it is just plain nutty or even impossible, let me know...

At this point, if it is even possible, I'd like some input on where I can find a compatible smaller ring (maybe 26t?).

Thanks!

I think your 26t idea has merit.
Check the available gear combinations you would get with it on:
http://sheldonbrown.com/gears/
If you are concerned with overshooting the smaller ring when you really need a reliable downshift (talking from my experience) try N-Gear Jumpstop. It forces the chain to go to the small ring no matter hwo fast/hard you downshift. It doesn't do anythinf for the bigger uspshift, however.
Check the BCD pattern you have to find what rings are available.

 

[brightgarden]

ok. got some options (options are good). the only final question might be whether I have the physical upper body strength to use the crank puller... never used one of these things before.... but I do have a buddy who could lend a hand if necessary.

 

[boudreaux]

Originally posted by brightgarden
ok. got some options (options are good). the only final question might be whether I have the physical upper body strength to use the crank puller... never used one of these things before.... but I do have a buddy who could lend a hand if necessary.

If it's the kind of puller without a handle,just use a long enough wrench to get the leverage.

 

[brightgarden]

Originally posted by boudreaux
If it's the kind of puller without a handle,just use a long enough wrench to get the leverage.

I was going to get the Park CCP-4 tool because my friend's crank puller was one he'd used a few years back on his mtn bike, and I didn't want to trust that it would work... I assume the handle on it is probably long enough (although I still find the pedal wrench with its long handle sometime only just long enough to get enough leverage).

i don't think i drag around much bacon, but i'm not carrying a whole lot of meat either...

 

[boudreaux]

Originally posted by brightgarden
I was going to get the Park CCP-4 tool because my friend's crank puller was one he'd used a few years back on his mtn bike, and I didn't want to trust that it would work... I assume the handle on it is probably long enough (although I still find the pedal wrench with its long handle sometime only just long enough to get enough leverage).

i don't think i drag around much bacon, but i'm not carrying a whole lot of meat either...

The CWP-6 is a universal tool that works with ocatlink,isis and square tapers and allows you to use your own wrench. Most people, and even shops overtighten pedals, so a long handle can be good to have but not necessary if you do it right yourself.

 

[brightgarden]

Originally posted by boudreaux
The CWP-6 is a universal tool that works with ocatlink,isis and square tapers and allows you to use your own wrench. Most people, and even shops overtighten pedals, so a long handle can be good to have but not necessary if you do it right yourself.

Ah yes, i did see that tool, and thought about it briefly. But considering that i have a sewing kit and not a tool chest, i figure it's cheaper to get just the CCP-4 rather than both the CWP-6 and a wrench.

but since i don't have a wrench, i don't suppose you mind suggesting a good universal wrench that i could get. last time i stared at a wall of these, i was perplexed.

Well, i do have a wrench--it's a standard adjustable wrench with about an 8" handle. Will that do do you think?

 

[boudreaux]

Originally posted by brightgarden


Well, i do have a wrench--it's a standard adjustable wrench with about an 8" handle. Will that do do you think?

Good chance that would work. My bigger tool is a 12" adjustable that is needed to get a rip on a Shimano BB tool, plus everything else down to about 4". Home Depot and even wally mart have inexpensive adjustable wrenches good enough for ocasional use and sears often puts better stuff on sale for 1/2 price. You can also use a piece of pipe of proper inside diameter for your wrench handle for extra leverage.

 

[brightgarden]

ahhhh.... well. i'll probably stick with the 30t inner ring just because I can't tell what smaller rings are even available. Is compatibility really just based on the BCD? so if i find a 28t or 26t ring with a BCD of 74, it should work?

In other words, can these things be mixed and matched--I was inclined to look for a Shimano ring, but they don't seem to be out there, or at least not easily findable by me.

It's supposed to rain like heck all week, so it seems like a good idea to spec it all out before I commit, or just go with the 30t and suck it up.

 

[Gonzo Bob]

Originally posted by brightgarden
ahhhh.... well. i'll probably stick with the 30t inner ring just because I can't tell what smaller rings are even available. Is compatibility really just based on the BCD? so if i find a 28t or 26t ring with a BCD of 74, it should work?

Yeah, in general, any 5-bolt, 74mm BCD chainring will work. I put Sugino chainrings on a Shimano crank and they work great.