Bicycle Mechanics - Round peg in a square hole - 11-32 cassette on a road derailleur designed for 28

Currently have an Ultegra 9spd standard 39-53 front 12-25 rear.
Can I TEMPORARILY (one ride) run an 11x32 cassette on that derailleur if I don't use the 32? (disregard chain length as the only time I would be in the 28 is when on the small front)

OR for added safety from accidentally shifting into the 32, could I swap out one of the sprockets from a different mfr (ie Sram Shimano) with another?
(I could add a sprocket from my Ultegra cassette onto the SRAM 11-32, then remove the 32 and be left with 28 being the largest gear)

IE: REMOVE the 32 SRAM in the 11,12,14,16,18,21,24,28,32 ADD a Shimano 15 sprocket and make it a
11,12,14,15,16,18,21,24,28

Concerned if there is a ramp issue between mfr's for 9speed cassettes.

If it doesn't clear the 32, then just lock out the last gear with the 'L' screw (low limit), on the rear derailleur, you'll turn your bike into an 8 speed but that's ok with you anyways right? You don't need to mess with the cassette at all this way.

if its an ultegra long cage, you can probably run the 32 with no problems. Just maybe need to screw the B-Screw in a little further. some bikes with a short deraileur hanger can't handle the 32 even with the long cage ultegra but I've had it on 3 bikes without issues. This is currently the setup on my bike. Otherwise, do like you said, don't even try to shift into it. The bigger issue is chain wrap capacity on a triple when your in the small chainring. But your riding a double so that is a non issue.

if its an ultegra long cage, you can probably run the 32 with no problems. Just maybe need to screw the B-Screw in a little further. some bikes with a short deraileur hanger can't handle the 32 even with the long cage ultegra but I've had it on 3 bikes without issues. This is currently the setup on my bike. Otherwise, do like you said, don't even try to shift into it. The bigger issue is chain wrap capacity on a triple when your in the small chainring. But your riding a double so that is a non issue.

Whether the derailleur is a long cage Ultegra or short cage Ultegra makes no difference in regard to largest cog compatibility, the derailleur body is the same.

This has to be one of the most misunderstood issues on the bikeforums mechanics forum.

It will likely be fine even if you do use the 32. If the chain is long enough, the worst thing that will happen is the derailleur jockey wheel will ride right on the 32 cog and be noisy and rough.

If you chain is not long enough, however, and you shift into the 32 then later shift into the large chainring (52 or 53 or whatever) you might violently rip your derailleur in half... guaranteeing that you only get one ride.

Also remember that any Shimano mountain derailleur (Alivio, Deore, SLX, LX, XT etc) will work just fine with the 32 if you decide you want to run such a big cog regularily.

I'm not sure about your situation, but if you are borrowing a cassette from soneone for the ride, and the cassette is worn considerably less or more than your chain, there will be problems.

Whether the derailleur is a long cage Ultegra or short cage Ultegra makes no difference in regard to largest cog compatibility, the derailleur body is the same.

This has to be one of the most misunderstood issues on the bikeforums mechanics forum.
That's quite true that derailleur cage length has no bearing on how large a cog it will clear and you are further correct that a lot of posters don't understand that.

However, cappuccino911's comment was; "some bikes with a short deraileur hanger can't handle the 32...", which is correct.

That's quite true that derailleur cage length has no bearing on how large a cog it will clear and you are further correct that a lot of posters don't understand that.

However, cappuccino911's comment was; "some bikes with a short deraileur hanger can't handle the 32...", which is correct.

I see your point, but I think I was correct in interpreting an implication that the derailleur cage length would make a difference as well. Maybe not, sorry if I misinterpreted. I still say it's one of the most misunderstood issues on the forum, and it comes up quite often.

I still say it's one of the most misunderstood issues on the forum, and it comes up quite often.
+1. No question about that.

Ultegra long cage with an Ultegra triple and an 11-34 way out back... she shifts beautifully.

http://www.ravingbikefiend.com/bikepics/arvonworldtourist1.JPG

The length of the derailleur hangar has significant effect on a derailleur's capacity and with many road bikes a shorter hangar, which is designed for a shorter cage derailleur, is what limits the derailleur from handling more teeth.

Ultegra long cage with an Ultegra triple and an 11-34 way out back... she shifts beautifully.

http://www.ravingbikefiend.com/bikepics/arvonworldtourist1.JPG

The length of the derailleur hangar has significant effect on a derailleur's capacity and with many road bikes a shorter hangar, which is designed for a shorter cage derailleur, is what limits the derailleur from handling more teeth.
Good grief, what is that thing??? I've seen cars with shorter wheelbases! :D

Obviously that bike is very utlilitatian and I expect the rd hanger is also particularly long to allow large cogs. It certainly isn't typical.

I love that bike! A person with clown shoes could ride that bike with panniers and have no heel strike problems.

Good grief, what is that thing??? I've seen cars with shorter wheelbases! :D

Obviously that bike is very utlilitatian and I expect the rd hanger is also particularly long to allow large cogs. It certainly isn't typical.

Austim Mini - 80 inch wheelbase
Smart Car - 71 inch wheelbase
Arvon World Tourist - 60 inch wheel base.

:)

The Arvon gets better mileage and is designed for touring and as such is set up to run a wider gearing range and fitting a longer rear hangar really opens up the choices on can make for drive compnents.

Really like the 8 speed Ultegra as it hits a sweet spot on price, looks fantastic, and shifts really beautifully... we have been building up quite a few bikes with Campy groups which don't look nearly as nice.

"I love that bike! A person with clown shoes could ride that bike with panniers and have no heel strike problems."

We build a lot of bikes for very tall people... this one is only a 55cm and am working on a similar model that will be 70-72 cm.

Recently someone one the Harris Cyclery site said they'd got one of the new Shimano 11-36 cassettes (which are claimed to only be compatable with "Shadow" style derailleurs) to shift well with a regular Deore der. by replacing the B screw with a 4x20mm bolt. I wonder if the same could be done in this situation without sacrificing too much in terms of crisp shifting.

Recently someone one the Harris Cyclery site said they'd got one of the new Shimano 11-36 cassettes (which are claimed to only be compatable with "Shadow" style derailleurs) to shift well with a regular Deore der. by replacing the B screw with a 4x20mm bolt. I wonder if the same could be done in this situation without sacrificing too much in terms of crisp shifting.

Although I don't have a use for one would like to do some experimenting... we have a test stand at the shop that will run pretty much any set up one can imagine.

Figure that modern Shimano long cage mtb derailleurs should be able to exceed their 34 tooth capacity and 38 tooth cogs have been made in the past... Suntour offered a 14-38 range as part of a mega range alpine group and developed a special rear d for this.

I love that bike! A person with clown shoes could ride that bike with panniers and have no heel strike problems.

Who makes SPD compatible clown shoes? The real problem with clown shoes is toe strike.

Who makes SPD compatible clown shoes? The real problem with clown shoes is toe strike.

They make clipless shoes in huge sizes and have seen size 18's... my friend has size 16 feet and has to use modified racks on his bike to prevent him from kicking his panniers.

The challenges very tall / large people have in finding bicycle to fit is not just limited to frame size as the frame's geometry and wheelbase should be adjusted to compensate to offer a properly tuned bike.