Bicycle Mechanics - Can I swap my 46 for a 53?

My bike came with a TruVativ Elita SL Cross, 38/46 setup.

Can I swap a 53 chainring for the 46?

What other adjustments would I need to make if it's a straight bolt in replacement?

You have to make sure your front derailleur can handle the extra teeth. You'll also need to move it upwards to clear the larger ring.

You also need to make sure it has the same BCD.

You have to make sure your front derailleur can handle the extra teeth. You'll also need to move it upwards to clear the larger ring.


I realize I'll have to move the front derailer higher for the increased diameter of the 53 ring.

What do you mean by making sure it can handle the extra teeth?

You also need to make sure it has the same BCD.

I assume you mean bolt circle diameter. If this is the case, they look the same and I'll make sure they match exactly before taking before removing the old ring.

Unless you meant one of these other definitions of BCD:

Barrels per calendar day, a unit for measuring output of oil refinery|oil refineries
Beirut Central District, a neighborhood in downtown Beirut
Binary-coded decimal, numbering
Birth Control Device, contraceptive or slang for military issued goggles
Board-certified diplomat, a professional credential
Boot Configuration Data, a computing term for the boot loader for Windows Vista
The Brainchild Design, website
The British Columbia Dragoons, a Canadian Forces armoured regiment based in Kelowna and Vernon
Buoyancy control device used in scuba diving
Zero-power Bi-stable Cholesteric Display

I'm just saying is all.....

Can I swap a 53 chainring for the 46?

This is one of those questions that looks so simple at the outset but becomes progressively messier the more you look into it. The short answer is "Almost certainly not."

1. You didn't give us much data about what actual crankset you have. Looking in my catalogue the only Truvative cranksets I see have 104mm 4 arm chainrings. I couldn't find a 53t chainring in that configuration.

2. If you did find one, you'd be advised to lengthen your chain to safely cover the big/big combination.

3. If you lengthen the chain it'll probably exceed the slack take up capacity of your rear derailleur.

4. Once you solve all of the above issues, it's time to consider the front derailleur. The arc of the derailleur that came with your bike won't match the larger diameter 53t chainring. If you move it up high enough that the heel of the derailleur cage will clear, you're going to have problems with shifting and rubbing in your granny ring.

5. How is your front shift cable routed? Most bikes like yours use top tube routing and an up-pull front derailleur. All of the front derailleurs that are designed for use with 53t chainrings have under the bottom bracket cable routing and down pull derailleurs.

See what I mean?

This is one of those questions that looks so simple at the outset but becomes progressively messier the more you look into it. The short answer is "Almost certainly not."

1. You didn't give us much data about what actual crankset you have. Looking in my catalogue the only Truvative cranksets I see have 104mm 4 arm chainrings. I couldn't find a 53t chainring in that configuration.

2. If you did find one, you'd be advised to lengthen your chain to safely cover the big/big combination.

3. If you lengthen the chain it'll probably exceed the slack take up capacity of your rear derailleur.

4. Once you solve all of the above issues, it's time to consider the front derailleur. The arc of the derailleur that came with your bike won't match the larger diameter 53t chainring. If you move it up high enough that the heel of the derailleur cage will clear, you're going to have problems with shifting and rubbing in your granny ring.

5. How is your front shift cable routed? Most bikes like yours use top tube routing and an up-pull front derailleur. All of the front derailleurs that are designed for use with 53t chainrings have under the bottom bracket cable routing and down pull derailleurs.

See what I mean?

I see exactly what you mean, excellent reply.

1. I'll check what I've got.

2. That sounds like the smallest issue.

3 & 4. Not sure these will be problems. The rear is a 9 speed Ultegra and the front Shimano 105 currently set up for a double ring. This should be fairly straightforward.

5. Correct. The routing is under down tube, under bottom bracket. I do have what look like standard Ultegra LFight Deck STI shifters, not sure if this would be an issue.

If what you were saying is it seems like to much work for what I'll get, point taken.

I think I'll wait till I'm spinning the gears I have like crazy before I go to the 53 and the extra 15% with regard to gear inches I'd see from the swap.

The Truvativ Elita set on my '03 Novara hybrid is 130BCD 5 arm and came with the "cyclocross" 39/48 rings. More recent ones came with 38/46 (which is what my rings now are and which my legs appreciate). To turn an Elita cyclocross crankset into a road crankset, all you have to do is replace the big ring with a 53. Then you still have the derailleur issues, etc. to consider.

If the front derailleur is shimano 105, it will handle a larger chainring since 105 is a standard road group. You will have to move the derailleur up ( look at the Shimano site for instructions on installing the derailleur, with a drawing showing proper clearance between the derailleur cage and large chainring ), also will need to install a slightly longer cable, and will probably have to add one or two links to the chain ( also explained on the Shimano web site) .

You have to make sure your front derailleur can handle the extra teeth. You'll also need to move it upwards to clear the larger ring.
And you'll also need a new chain and a new shift cable.

Sheldon "Necessities" Brown

Thanks to all those that replied.

I was hoping it was a simple bolt for bolt replacement, obviously it is not.

I will wait until I literally "outgrow" the 46 and consider my options at that time.

This thread proves once again what an indespensable resource Bike Forums is.

And you'll also need a new chain and a new shift cable.

Sheldon "Necessities" Brown

Never thought about the shift cable. Just goes to show, those little things can add up in the long run.

Tim