stuckinnj

Hi all,

I have a Trek 5200 with 53/39 chain rings, a Ultegra 12/27 cassette and a Ultegra 6600 series rear derailleur. Due to a old knee injury that sometimes causes a bit of discomfort I need to lighten the load on my knee when climbing. I would like to keep the surgery on the bike to a minium as well incase this does not work out and I have to go back to my 12/27 cassette. As a result I figured I would start by just changing the cassette to see where things end up.

Can I simply order a Ultegra 12/30 10 speed cassette and swap it or do I have to add links to my chain and will a Ultegra 6600 series rear derailleur even be able to work with a 12/30 cassette ?

Thank you in advance.....

zacster

I'm assuming a 5200 has a road double and an Ultegra 6600 SS rear derailleur. If that is the case, the answer is no based on the documentation where you are already at the max of 29 capacity (53-39+27-12) and the largest cog size of 27. That said, it may work since there is a little slack built into the capacity. It could be a stretch though, and that would play into chain length too as it may not have the capacity to take up more chain. Where you'll see problems is big/big if too short and small/small if too long. And the big rear cog with the derailleur may not work. A 6700a derailleur would work better based on this chart: Compatibility Chart but I don't see any being sold on ebay specifically as 6700a.

Maybe look into a compact crank instead? But you can't just replace the rings as the BCD on a normal double is usually 130 and on a compact 110, and I have no idea if Shimano cranks from that era used standard sizes.

It's a slippery slope when you want to make even small changes to drivetrains. That small little change will create a whole cascade of other changes that need to be made.

shelbyfv

Maybe.... As you probably know, the 30T is beyond spec for the 6600 RD but often works. You just have to try it. When you get it installed, shift to the big/big and be sure there is still some slack for the derailleur. If not, you'll need a longer chain. Actually, since you are buying a new cassette you may as well get a new chain and size it properly from the start. You won't gain a lot by the change, FWIW. Probably more useful to swap to a 50/34 crank. Edit- and all of above^^^

sch

30T cassette will get you ~10-11% reduction in perceived torque needed on hills, not insignificant. Likely your RD will cover the
30T, but as noted chain wrap may (but not likely) be a problem. I would add one inch to the chain length and as noted changing the chain is
also a good idea with a new cassette. If the RD can't be adjusted to clear the 30T by B screw movement or even reversing the
B screw then an $8-10 RD hanger extender from Amazon will fix that.
Just looked at amazon and extenders are plentiful but a bit more pricey in the covid era than a year ago. Still some below $12 but
$35????

delbiker1 

You can get a Tiagra 4600 mid-cage rear derailleur off Ebay for $40 plus $8 shipping, listed as take off new without packaging and minor blemishes. Also, Vuelta has 48T and 38T chainrings for 130bcd cranksets. The Vuelta SE Plus has ramps and pins. The regular SE and flat rings do not. How much money and effort do you want to put into it? Amazon has the 48T SE Plus for $40. https://www.amazon.com/Vuelta-868860...7&sr=8-22&th=1

70sSanO

I’d run a 9 speed MTB derailleur with the 10 speed road drivetrain. It will work without any issues and give you all the cog and capacity range you need.

The compact crank is also a good suggestion, or a triple.

I’m running an Ultegra triple with an XTR rear derailleur; but an XT-750 is also nice. I only use the small ring as needed, so it is basically a double for most rides.

John

dsbrantjr

Whatever you do you must be certain that the chain is long enough to shift into the big-big combination without strain, to avoid drivetrain or frame damage. As others have noted it is a good idea to get a new chain to go with your new cassette and to size it correctly. If your chain wrap capacity is too little you may have a slack chain in small-small, but you should avoid those combinations anyway. Worst case any Shimano or compatible mountain derailleur up to 9-speed will work with your shifters.

Barry2 

Here, you might like this
Oh, and yes... the chain does get longer.

Barry

zacster

That's what I referred to above, but as far as I've seen there are none being sold specifically as the "A" model, probably because most people don't know it even exists as a different model. I just saw it on the chart as being perfect for what the OP needs, but checked the usual source for used components.

Will the MTB derailleur work? I just checked a chart and 9sp mtb and road are the same, and that wouldn't be compatible with 10sp road, nor is 10sp mtb anywhere close since it uses Dynasys. This is why you should just stick to the same system.

70sSanO

Can't use 10 speed MTB RD. Need to use a 9 speed MTB RD; can probably be able to use an 8 or 7, but I'd find a 9 speed.

John

Barry2 

Sorry Zacster, I was not clear.
OP, I didn't mean that the 6600 was available in the "A" version. AFAIK that was only the 6700's.
The reason for the link was to help understand how Shimano spec's it's derailleurs.

I found that once I better understood the Spec's and how the limits were applied, I could make a informed decision of what to change.

All the best

Barry

Wanderer

Might still be able to find a 105 long cage that will work.

tomtomtom123

As others have said, changing from 27 to 30 max cog is 30/27 = 11.1% step. It's like 1 gear. If you want even lower, you could also decrease the size of your chainrings. Also as others have said, the 6600 would be a little over published max cog capacity but maybe still ok for 30t cog but you would have to test it to find out. SS cage would probably be too short by 2 or 3 links since it's over chain wrap capacity, so if you increase the chain length to clear the big-big, then you would not be able to use the outermost 2 or 3 cogs on small-small since the pulley will drag, and it's maybe ok if since the gear range overlaps anyway.

I have 12-34T 10 speed cassette and 44/24T double chainrings. for 519% range.

I purchase a CS-4700 12-30T 10 speed cassette for $25 and mixed the cogs with other cassettes to get 12-34T, 12, 13, 14, 15, 17, 19, 21, 24, 28, 34. I just dropped the 27 and 30, and added the 28 and 34 from another 2 cassettes. If you don't want to drop so much, you could also simply drop only the 30 and add a 32.

If you do go up to 34T max cog (or 32T), you would probably have to switch to a different RD with more capacity in both max cog and chain wrap. If you switch RD, make sure that you use a compatible RD with the same cable pull. The RD-4700 and GRX models uses a different pull ratio so you'd have to also change the shifter. I read somewhere that others use MTB 9 speed RD to replace the short pull 10 speed road RD.

I also use double chainrings with a 20T jump, 44/24T. 20T jump is ok as long as you have a chain catcher. The chain will rub on the outer chainring when on the outermost 3 cogs on small-small, so you won't be able to use those gears but the range overlaps anyway so you may not need them. You could add a couple of 0.1mm thickness DIN 988 shims to the inner chainring to move it a little bit further from the outer chainring to reduce chain rub by 1 more outer cog. 100 pack costs like $2-5 on eBay.

However, if your crank uses 130 BCD, you can only go down to 38T minimum. If you use 110 BCD, that's 33T minimum. TA and Stronglight make a triplizer ring to give you a 74 BCD triple, but you'd have to switch to a triple FD and shifter. You might then want to consider switching to a crankset with smaller BCD.

Bill Kapaun

This is how a do a quick & dirty chain length check for cases like this.
A 3T larger cog would mean you need a "nominally longer" chain by 3/4". So, IF you have 1-3/4" or more "excess", you're good as far as chain length goes.
Put it on the largest ring & cog and grab a couple skinny items.

stuckinnj

What @zacster stated makes a lot of sense "It's a slippery slope when you want to make even small changes to drivetrains. That small little change will create a whole cascade of other changes that need to be made." My 5200 has been a solid performing bike since the day I got it from my LBS. I think I'll leave my 53/39 12/27 combo on there and just work through the climbs. I want to spend what time I have ridding rather than fiddling with gear.

tFUnK

I would suggest getting a compact crank (50/34) AND changing the cassette to 12-30. That way the chain length should be able to stay the same and you'll get some nice low end gearing. The RD isn't spec'ed for the 30t large cog but many folks have been able to go 30, or even 32 in some cases.

zacster

That's because I've been there and I'm in the same boat myself, I want to go from a 13-26 to 13-29 Campy Chorus 10, but it may require a different derailleur, and then a longer chain, and will the front still align? Nah, I'll just ride the 13-26 until I can't ride anymore. Besides, the last few times I was anywhere with serious hills I had rentals with very wide gearing. My SF bike had a 50/34 and 11-34 rear. You need that in SF sometimes. My Haleakala bike had a 30 cog rear and 50/34 front. For that ride a 34 would have been nice. But in NYC I hardly ever go off the large ring in front.