Road Bike, Cycling Forums banner
1 - 16 of 16 Posts

·
Registered
Joined
·
100 Posts
Discussion Starter · #1 ·
Sorry if I didn’t find a prior discussion, but I’m wondering if it is possible to run a 50-39 chainring setup. On any top platform.

Or, I suppose, is there a way to make the last (smallest) cog on a modern cassette (10speed or 11speed) usable with a 39 inner ring without the chain rubbing on the big ring?

I’m trying to make my small ring usable with a 39X12 gear. I can do it with an 11-xx cassette, but I have ZERO use for an 11 with a 52 or 53 tooth big ring. I hate to put on an 11 tooth cog JUST TO MAKE THE 12 ridable.

I miss the days of being able to actually use my smallest cog with a 42 inner ring…

Your thoughts?
 

·
Registered
Joined
·
14,713 Posts
My thoughts:

Why the nostalgia for cross-chaining? You can get the same ratio as 39/12 with 53/16.

I miss the days of being able to actually use my smallest cog with a 42 inner ring…
Well, you arguably needed that 42/14 sometimes when you only had 5 or 6 cogs on the freewheel. Now, with 10 or 11 cogs, you have a better way.
 

·
Registered
Joined
·
12,061 Posts
Sorry if I didn’t find a prior discussion, but I’m wondering if it is possible to run a 50-39 chainring setup. On any top platform.

Or, I suppose, is there a way to make the last (smallest) cog on a modern cassette (10speed or 11speed) usable with a 39 inner ring without the chain rubbing on the big ring?

I’m trying to make my small ring usable with a 39X12 gear. I can do it with an 11-xx cassette, but I have ZERO use for an 11 with a 52 or 53 tooth big ring. I hate to put on an 11 tooth cog JUST TO MAKE THE 12 ridable.

I miss the days of being able to actually use my smallest cog with a 42 inner ring…

Your thoughts?
knock yourself out.
https://www.sjscycles.co.uk/chainri...rm-outer-chainring-b-type-silver-50t/?geoc=US
not sure you want to know our thoughts though :)
 

·
Registered
Joined
·
5,393 Posts
You don't even need to change your big chainring, just shift to the 50/15. You just love to miss something? It was not that great!
 

·
Registered
Joined
·
8,224 Posts
One does not choose small chainring size to match small cog. Setting up one's gearing for a max cross chain situation is rather foolish IMO. If you want a 39, then the 50 is pointless. The 50 is simply a compromise to allow a smaller small chainring. Go get a standard 53/39 crankset and be done with it if you insist on the 39/12, small small combination.
 

·
Registered
Joined
·
77 Posts
I did it for a while on my Shimano 9000 crank. The chain was getting stuck between the rings when shifting so I had to to 50/34t. Apparently you can only run combos approved by them or you'll have issues.
 

·
Registered
Joined
·
100 Posts
Discussion Starter · #8 · (Edited)
Thanks for the link den bakker. I run a DA 7900 (Type B) crankset… This is a 7800 but it seems that it would work…

Perhaps an explanation will make my interest in a 50 more understandable.

I spend a lot of time riding 22-24 mph, with gently rolling grades or wind that slow me to 19 or so and speed me up to 25 or so. With a 12-23, I’m forced to the big ring as the 13 (the smallest ridable cog) spins out around 23mph.

To get the small ring to be usable at those speeds, I need to run an 11-23. But, that takes away my 18 which is right in my sweet spot of riding on the big ring.

Further, an 11X53 is stupid big for me. 25 years ago I raced on 13X53s and never lost a sprint for lack of a bigger gear. I sure don’t need that monster gear now, or even a 12X53 or 52, for that matter.

My old racing bike has 90s Campy Record that is 42X53, with a 9-speed 13-23 that frankly is more usable BECAUSE the 13 is ridable with no cross-chain issues.

When I trained and raced, we all used every gear on our bikes when necessary. We laughed about people “ah-pooing” cross chaining because when you NEED that gear, you NEED that gear. I still ride that way, I guess.

Anyhow, with the move to 10 speed systems, suddenly the smallest cog isn’t usable in the small ring for all the clanging it makes (at least in a 39-53 setup). My thought was, with perhaps with a smaller big ring, the chain won’t clang so much or at all in the 39-12 and I can keep my 18 for the big ring cruising AND be able to cruise at the lower end of my normal riding in the small ring.

In short, I’m just trying to put both BOTH rings in a position to work well at my normal riding pace.<script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/3971727f/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/3971727f/background/helpers/prefilterHelper.js"></script><script type="text/javascript" src="safari-extension://com.ebay.safari.myebaymanager-QYHMMGCMJR/3971727f/background/helpers/prefilterHelper.js"></script>
 

·
Registered
Joined
·
21,637 Posts
I spend a lot of time riding 22-24 mph, with gently rolling grades or wind that slow me to 19 or so and speed me up to 25 or so. With a 12-23, I’m forced to the big ring as the 13 (the smallest ridable cog) spins out around 23mph.

To get the small ring to be usable at those speeds, I need to run an 11-23. But, that takes away my 18 which is right in my sweet spot of riding on the big ring.
Why on earth do you want the small chain ring to be "usable at those speeds"? Those speeds are why we have big chain rings. The riding you describe should never require you to use the small chain ring.
 

·
Registered
Joined
·
12,061 Posts
My old racing bike has 90s Campy Record that is 42X53, with a 9-speed 13-23 that frankly is more usable BECAUSE the 13 is ridable with no cross-chain issues.

When I trained and raced, we all used every gear on our bikes when necessary. We laughed about people “ah-pooing” cross chaining because when you NEED that gear, you NEED that gear. I still ride that way, I guess.
no we did not. speak for yourself.
 

·
Registered
Joined
·
3,695 Posts
If your routes are not severely hilly I say go for it. Personally I feel 53-39 set-ups seem to feel stiffer and faster. It's not simply finding an equivalent pair of gears. It is a small difference for sure however if you are not climbing double digit grades for long durations the advantages of a compact just aren't there in my opinion. Now if you are planning on climbing Stelvio or Madeleine I'd say stay compact.
 

·
Registered
Joined
·
3,374 Posts
It is a small difference for sure however if you are not climbing double digit grades for long durations the advantages of a compact just aren't there in my opinion.
I love it when people who don't know my weight, my power, my roads, my cadence preference tell me what equipment I should use.
 

·
Registered
Joined
·
27,471 Posts
I love it when people who don't know my weight, my power, my roads, my cadence preference tell me what equipment I should use.
Hey look, we got it all figured out. Been there, done that. What else is there to say?

Why give up a perfectly fine 53 tooth gear, when its there when you need that one final spurt of speed to become a truly great cycling hero? Don't wimp out with a damn 50T! You'll regret it. If you want to go hard, put a 39 or 42 in there. A 42[or 39] would be a great tempo gear, useable with the most gears in back at cruising speeds, 12-18 mph.

I used a 50 one year. I kept spinning out on the club rides chasing the 52 and 53s down the road. It was still harder than the 42, but a bit too easy than the 52, and the legs never adjusted. Nice tempo gear on the flats, 16-22 mph, but a little too hard for climbing and too easy for sprinting or going faster in a pack or tail wind. Still got it in a box. Might put it on after my 75th birthday.

So far, 52, 53 rocks on. Spinning the larger rings seems to develop more torque and is a little easier. Legs frequently felt sluggish in the 50. :ihih:
 

·
Registered
Joined
·
14,713 Posts
Why on earth do you want the small chain ring to be "usable at those speeds"? Those speeds are why we have big chain rings. The riding you describe should never require you to use the small chain ring.
Seems that way to me. 53/19 at 90 rpm is 19 mph, right?
 
1 - 16 of 16 Posts
Top