Chainring Question???

Forum guidelines BT super discount
General Discussion Triathlon Talk » Chainring Question??? Rss Feed  
Moderators: k9car363, alicefoeller Reply
2013-02-05 1:43 PM


3

Subject: Chainring Question???

I've always used a 53/39t up front but my current ride came with a 54/42t. Does anyone know if I can just swap out the 42t for a 39t and keep the 54t? Or do I need to swap out both up front?

Thanks

2013-02-05 2:13 PM
in reply to: #4609752

User image

Champion
10668
500050005001002525
Tacoma, Washington
Subject: RE: Chainring Question???

Not a simple answer, unfortunately.

Yes, physically you can make that switch. The issues pop up with what rear derailleur and cassette you have. Most road short-cage derailleur have a total capacity of 28 teeth, meaning the total different between the front chainrings and the rear cogs has to be equal or less than 28. A 54-39 combo up front will limit you to a 12-25 cassette. Also, with a larger gap in front, there's a greater chance of throwing the chain off when downshifting.

2013-02-05 3:47 PM
in reply to: #4609811


3

Subject: RE: Chainring Question???
Hey thanks for the reply. Throwing the chain up front during downshifting is what I'm affraid of. Old setup was 53/39t with 11-25 in the rear. New is 54/42t with 11-25 in the rear. $$$ Money wise $$$, I was hoping to just be able to swap out the 42t for the 39t.
2013-02-06 9:32 AM
in reply to: #4609752

User image

Extreme Veteran
1001
1000
Highlands Ranch, Colorado
Subject: RE: Chainring Question???

I agree with what others said in that your main worry of going 54/39 is throwing a chain.  A few years ago I was riding a 54/42 and changed out the 42 for a 39 for a mountain century ride.  I had to stop several times on the ride to put my chain back on the ring, as soon as I got home I changed back to the 42.

I changed out the cassette for a 12/28 which worked for most of the time. 

New Thread
General Discussion Triathlon Talk » Chainring Question??? Rss Feed