yespatterns

The title is a bit misleading... what I'd like to do is have my cross tires on my extra wheelset with a mountain cassette (11-32) for trail riding. The stock cassette on my Poprad is 12-26, and I'm wondering if the larger cassette will work with the 105 rear dérailleur and overall setup. Any ideas on this? Thanks in advance!

mtmann

I haven't tried it, but don't be surprised if it doesn't work. I've read that with anything bigger than a 28 in the rear you're going to need a long cage derailleur - which you don't want on a cross bike anyway because it's just hanging down there asking to get snagged or snapped off. But if you try and it works, let us know - I have a Poprad with a 105 rear as well.

DDYTDY

I'm running a 11-32 9 speed with a medium cage derailer with no problems.

I think it may work. A friend of mine runs an old Shimano 600 road derailer on his 1x8 MTB with a 12-30 cassette.

yespatterns

Do you think the stock 105 is a medium? Is there anyway I can tell?

I'll definitely report back, as I'm dropping by performance tonight to grab some tools, the cassette, etc while the 15% off sale is on.

Cyclist01012

I run A single 42 tooth chainring with a 11/32 cassette No shifting what so ever. In fact this shifts better then the 11/25 i tried at first.

Oh yea the der I'm using is one of the Sora rears that everyone complains about. Streched the cable, put it on, dialed it in, and it has shifted flawless sence then.

flargle

I think the short answer is you won't know until you try, but here are some more guidelines:

https://sheldonbrown.com/k7.html#roadmtb

Sawtooth

I switched from a 12-26 to an 11-32 with no problems. I don't believe I have a long cage derailer but am not sure. Of course, the downside is that you have more gap between gears. The upside is that you can climb just about anything.

Sawtooth

Stretching the cable is new to me.....what does that mean? How did you stretch it?

knobster

I have a medium cage Ultegra RD and a 12/27 cassette. It is a bit noisy in the 27, so I think you'd be playing with fire switching to a 32. I'd look on EBay and pick up a used long cage RD. You'd be fine then.

barba

I doubt the 105 RD will handle 32 teeth. I would just buy a cheap mountain derailleur (Nashbar has a Deore for something like $16).

M_S

Which means you can afford to break it. The deore shifts pretty well, too.

I'm not sure I buy the "hanging there and snapping off/snagging" argument against long cage. Mountain bikes use them, and even most cross country trails have a lot more junk littering them than your average cyclocross course.

yespatterns

Thats a pretty good idea... I do have an LX long cage floating around that I was hoping to use on a mountain bike, so maybe I'll just throw that on and see how it feels. I appreciate everyone's advice, and I may still try it with the 105 on the repair stand just to see, and if I do, like I said, I'klll let you know what I find out.

M_S

Sure, no harm in trying the 105. And LX is basicaly the same leve as 105 anyways. Report back with your results

Cyclist01012

Sora and 105 are the same size cage.

luker

Most cables will stretch a little with time. Just put it on, ride it for a week or two, and adjust the rear shifting. Yer done!

105's come in various cage lengths depending on the model and the year. A road racing 105 will not be happy with a 32; a 105 triple will eat it up. You may be able to get a short 105 to work if you only have one chainring up front...

dzinehaus

105 long cage will handle 32 teeth... not suggested but it will... a 105 short cage goes up to 27 max, and I'm using a road 11-23 on mine with a short cage 105.

dzinehaus

is this the shimano mega range cassette with the 32t bail-out cog???

barba

Short and long cage road dérailleurs are rated for the same capacity. I would think the issue would be the body angle and the jockey pulley hitting the cassette, not chain wrap. Have you tried this in real life? I would love to hear that it works.

awright

I've run a 105 triple with a 32t and 34t cogs and a compact double. It shifts as well as Deore XT. I would be tempted to try a short/medium cage with larger cogs. The relative position of the jockey pulley would be the same on either der. The extra length of the cage is there for using a triple to keep chain tension. I would think with a standard/compact double a short cage might be fine.

late

I don't think Shimano says things like Mega Range anymore. But yeah... it's their Mtn bike cassette.

My 2 cents on the matter is that I am extremely fond of XT rear derailleurs and cassettes. It will set you back a few bucks, but worth it. Hold various cassettes in your hand. The XT will feel lighter than most.

Oh, and one last thing, a 30T bailout gear is also an option; one with more options for spacing the gears. Harris Cyclery makes one.

Wombatspeed

This is what I have been running for a few months.

Bike: Kona Jake. Front rings 48 39 26. Rear cassette is a regular 12-25 with the 13 taken out and a 32 added (for towing a kids trailer up steep hills). RD: 105 short cage (the one intended for a double).

This works fine - just don't cross chain completely. YMMV.

Caveat: My chain is on the short side (i.e. too short to use the 48 front with the 32 rear), perhaps this is what prevents the RD from hitting the 32 cog.

Bottomline: try it out, it may very well work.

M_S

Wait, I'm confused. So your 32 is in the middle of the cassette?

Does the derailleur have trouble making the leap up?

yespatterns

Success! I just got back from a very fun, very sweaty half hour or so on the single track around Forest Hill park. I dropped by Performance today and picked up their Forte 9 speed MTB cassette (14.99 - 15%), dropped in on my extra 32/32 wheelset, and it was a go. The trails were definitely a bit more challenging with the Jones 32mm tires, and the abundance of loose fist-size river rocks made things interesting, especially when picking my lines. But anyway, the conversion works without any dérailleur adjustment, and I highly recommend it.

Cheers!
John

telebianchi

So, John, just to clarify. You're using a 12-26 on one of your rear wheels and the mountain cassette on the other one? And you don't have to adjust anything when you switch one wheel out for the other? What is the cog set up on the new mountain cassette?

I ask because I just today installed a new set of Mavic Open Pro wheels on my Fuji Cross and have a 12-26 cassette on that. I was just going to keep the 12-26 on the old wheels but it would be kind of cool if I could use the larger big cog on that with the 32mm knobby tires.

I, too, have a 105 rear DR.

Thanks.

(Dang, this probably means I'm spending some more money.)

yespatterns

Exactly Telebianchi, I just switch out wheelsets between the Alex's with the knobbies and MTB cassette, and the stock Bontragers with slicks and the stock 12-26 without adjustment on the dérailleurs.

This is the cassette I dropped on:

https://www.performancebike.com/shop/...tegory_ID=5130

I've been stoked all day because the world duathlon championships bike route went by my house earlier today, and I've dying to get some pedaling done myself, so I'm hitting the trails in a bit with some friends