Shimano 105 Set with a change to either Triple or MTB Rear

pinguS

Hi all

Ok I have just read a few posts below mine, and some good information. But just to cut it short, I have two options I'm looking at to make hill climbs easier (and no I do not have enough time to train and develop legs, and I never ever go fast enough to care for clean gear changing) . But firstly what I have is
Compact Double 50/34
Cassette 11-28

All of this is the Shimano 105 groupset.

I have spoken to LBS and they recommend changind the Cassette as the cheaper option, but the two options they have given are
1. Change to triple, but cost is high as I need new Shifter / Front D / Crankset.

or cheaper way

2. Use a MTB rear, which I said I would like to be Shimano, but they say they have not really tried it with the 105 shifters.


So all I am really asking is has anyone done, this, i.e. using 105 shifters with MTB rear derailleur and cassette? The options they say to try are Shimano SLR range or XT range.

I'm not too worried about the extra 200 grams or so, seriously I'm more leisure type. I can go up hills no problem, but when I hit one after 25miles or so, I always walk even in the lowest gear ratio.

The other thing is, that If I change to MTB rear, I can always change back in the future when I am more comfortable.

pinguS

Oh forgot to mention, I don't really want to go through the Triplizer route, just the 2 options mentioned, and preferably Shimano. Just to keep things neat.

I know its against the Road Biking Law to even think of a triple or mtb read, but I'm ok with that.

Greggyr

Hi there

My chum added an MTB cassette and derailleur to his compact Trek 1.2, and it's revolutionised his climbing. It's by far the easiest & cheapest way of changing your groupset.

pinguS

Thanks, but do you know if his rear derailleur and cassette worked with the 105 groupset, or really the frint right shifter.

My one is the 10 cassette rear and shifter.

Also, how easy is this job. I am good hads on, but would like a good website to learn from so I can set it up right, or at least get everything on and then get the LBS to adjust it.

pinguS

The other question on MTB rear, would the XT work, I believe this is the similar range as the Road 105 groupset, i.e. price range and quality.

rothers_bikeo

Do you have 9 or 10 speed 105 ?

pinguS

I have a 10 speed 105 rear
Compact double 105 - 50/34 front.

Basically the whole bike is 105 Groupset, bit gutted I dodn't choose the triple setup when purchased. The dirty LBS guy said I will not need it and its for the weaklings.

Sorry to say, but I'm the weakling. And as I have kids and other hobbies, I can't stay my whole life on a bike and build the legs as I would like too.

pinguS

Also forgot to ask, will this still need a longer chain.

My choice is going to be a 11-36 cassette, most likely Shimano XT or SL stuff, with rear derailleur.

People will say that is real granny speed, but looking at the cassette its fine for what I need.

Mr Will

If you are struggling that much, I doubt a triple is the answer. It will only give you one gear lower than your compact currently goes (the rest is just overlap).

IIRC, the SRAM Apex 12-32 cassette is compatible with 105, and will give you a massively lower gear than what you have now, which should get you up anything this side of a brick wall.

This is very useful for comparing the various options: http://sheldonbrown.com/gears/

pinguS

Ok maybe the 36 at the back is really overkill, but just nice to have. Plus I was looking at keeping Shimano.

However, with the SRAM 12-32, isn't the 32 ring going to be too big for the Shimano 105 rear derailleur, or chain length too short. Not sure where I'm going wrong with this, but if the rings get bigger, does the chain need to be bigger or the derailleur need to be bigger.

rothers_bikeo

You need a 9 speed Shimano MB Rear Derailleur, a 10 speed MB cassette and a new 10 speed chain. These will be compatible with your existing 10 speed 105 shifters and compact double chain ring.

The new Shimano 10 speed MB Rear Derailleurs are not compatible with 10 speed 105 shifters.

pinguS

Ok so if I was to use a SRAM Apex 12-32 cassette, then I would need a 9 speed rear d, and chain, does that mean I lose a gear using the 9 speed rear derailleur.

There are alot of posts along this line, but all go too technical. I'm just looking for yes or no's really.

Or the easiest / cost effective way of doing it.

Mr will mentions the SRAM Apex 12-32 cassette, me being me would take that as just stick it on and go. but is that a obviously not ??

keef66

I thought Shimano MTB rear mechs operate with different cable pull from the road ones?

Presumably it would work with an Apex cassette and Apex rear mech??

(I ignored the naysayers and specced a 105 triple on my bike. Bottom gear isn't much lower than with a comp double, but I do have very closely spaced ratios so I can keep spinning)

rothers_bikeo

keef66 wrote:

I thought Shimano MTB rear mechs operate with different cable pull from the road ones?

The new 10 speed do but not the 9 speed.

pinguS

rothers_bikeo wrote:

keef66 wrote:

I thought Shimano MTB rear mechs operate with different cable pull from the road ones?

The new 10 speed do but not the 9 speed.

Ok, so which one is it exactly, sorry for lame question. But will the Right Front 105 Shifter operate a 9 or 10 speed Shimano MTB Rear Mech or SRAM model, as they have different cable pull. My Shifter is a 10 speed model 5700.

If it is the 9 speed, then do you lose a gear?

pinguS

Also just for curiosity sake, if anyone does have an answer to this.

If I want to add a 10 speed cassette with a 36t ring, i.e. 11-36 XT model or something. What exactly would I need to change, would the shifter really need chaging also in this scenario?

Reason for this is, with a 12 - 32 cassette, I will only get one lower gear, that being 32 at back and 34 at front. (in the 12-32 cassette, the next cog is a 28, which is my current lowest rear)

keef66

You had the answer already (I knew it was something like this)

"You need a 9 speed Shimano MB Rear Derailleur" to go with your existing 105 10 speed road shifter. But this will then work with the 10 speed Apex or MTB cassette, so no, you won't lose a gear.

pinguS

Sorry, forgot I read that post, ok so I am assumming if I want to Granny my bike for a * - 36 cassette, then I should go with the following

9 speed MTB rear Mech
11 or 12 - 36 MTB cassette
10 speed chain (would this be a road or mtb chain, if these are different.)

Also that would mean I could stick to all shimano if i wanted to.

Yes I am this lame to cycles at the moment.

pinguS

Also if anyone knows this, what part of the rear mech limits the size of cog that can be used?

cheers in advance

rothers_bikeo

pinguS wrote:

Also if anyone knows this, what part of the rear mech limits the size of cog that can be used?

The angle at which the parallelogram causes the jockey wheels to traverse across the cassette. MB derailleurs work at a bigger angle than road derailleurs.

pinguS

I'm thinking now it may be worth spending the extra, change to a triple and also reduce the crankset cog sizes. I assume as long as the BCD are the same, I can move from a triple 50/39/30 (which is what I think the 105 is) to some thing like 48/38/28 or something?

rothers_bikeo

To do that you'd need to change everything except your rh shifter.

pinguS

Oh wow, so now what do I do !!!

Triple front, change everything

Bigger back, change everything.

I think I'm going to change the bike, I only bought it 3 months ago. I know from trying a bike with a 34 front and 32 ring at the back, it just isn't low enough.

Or maybe, if I do go through the Triple route, I'm sure the Double shifters etc will sell ?? They pratically new.

My idea is to give a standard triple a go, i.e. 50/38/30 or whatever 105 standard is, and in few months if I need lower front granny gear, I'll look more into it.

Does that sound a better option, on grounds I could sell the other stuff.

rothers_bikeo

pinguS wrote:

Triple front, change everything

Yes

Bigger back, change everything.

No, only the cassette, rear derailleur and chain

When I changed from a 50/35 11-27 compact double on my hybrid to a triple I went for a full Deore FX 48/36/26 11-34 setup

Download some Shimano tech data sheets and have a read up on "capacity" and "max sprocket size" for the various short, medium (road) and long throw (mb) rear derailleurs.

To be honest I'd persevere with your current compact double setup for a while longer, after a year of clubs runs I can now get up pretty much anything on my road bike's 50/34 11-28

pinguS

Ok, maybe longoer riding will help. But I would like a slightly light gear for now. I have just been reading elsewhere

http://www.epicski.com/t/95361/sram-ape ... ar-no-hill

that you can just chuck on the SRAM Apex 11-32 onto the 105 compact setup and go, my bike has the longer RD (I believe shimano only make a short and long version of the 105).

Earlier in the posts, the Apex 11-32 was suggested, but not confirmed if the 105 large RD would cope. I believe the Total Capacity rated for it is 39t, which I presume is on my current setup is (50-34)+(28-11) = 33t.
So with the SRAM 11-32 this would only go to 37t.
Also its biggest cog rating is 28t, but I'm sure this is because thats the biggest Shimano have made, can't see SRAM out doing them?
Or would I be better of also chucking on the SRAM RD with the cassette, and keep everything else.

(oh and the chain, the god damn chain, does this need extending)

If anyone can suggest otherwise, is this worth a try?

pinguS

Have I just talked rubbish in my last post?

LongIslandTom

If you have the medium-cage 105 rear derailleur (5700GS), it will work with a 32T cassette. You just need to make sure the B-tension screw is set correctly so that the pulley will clear the biggest 32T cassette sprocket, and that your chain is long enough to accommodate crosschaining the biggest chainring with the biggest sprocket.

I've run a 105-equipped bike with a 5700GS rear derailleur and an SRAM PG1070 11-32T cassette with no problems.

Same applies to Ultegra 6700GS, for those who are running Ultegra on their bikes looking for a lower gear ratio.

pinguS

Thanks for that, I'll check it out tomorrow, do you know of any site that will instruct me exactly how to install the new cassette. and also change the tension screws?

Also I do have the medium cage 5700GS I believe, but to make sure would you know where the model markings will be?

And finally, what would be a large cage rear derailleur, is that MTB types?

cheers again

LongIslandTom

Far as I know, the Shimano road gruppos like 105 and Ultegra only has short-cage and medium-cage versions, no "long cage".

If you want to have a really big rear sprocket like a 36T, then yes you will need to find a mountain bike rear derailleur that has the same cable pull ratio as your 105 shifters to make it work.

Swapping out a cassette is very easy if you have the necessary tools. You will need three tools: A chain-whip, a lockring tool and a hex wrench (adjustable or socket). Video on how to do it: http://www.youtube.com/watch?v=jx9zNW7fhjY

Setting the B-tension screw: http://www.sheldonbrown.com/derailer-ad ... l#btension

Easiest way to determine which derailleur you got would be to look at the photos for the 5700SS (short cage) and the 5700GS (medium cage) and note their cage lengths, and compare it to what you got.

Good luck. I'm sure you will enjoy the lower gear ratios going up hills with a 32T cassette as much as I do mine.

Rodu

This sounds good, I am running a mix of circa 2009 105 and Ultegra 11-27 compact and fancy trying the same having had knee pain after grinding up Ditchling Beacon last weekend at the end of a long ride.

So I think I have a RD like the below but not sure exactly what model it is. From what I can tell between Short and Medium cage, the bit that holds the jockey wheel is either short and stubby or slightly longer.

Short cage
http://www.evanscycles.com/products/shi ... r-ec006449

Medium Cage
http://www.tredz.co.uk/.Shimano-Ultegra ... _27140.htm

I will check my bike when I get home tonight, if it is the slightly longer Medium then game on, I will try and put on the MTB SRAM PG1070 11-32T to easily get me around Surrey Hills and the occasional proper hill like Ditchling.
http://www.wiggle.co.uk/sram-pg1070-10- ... sette-mtb/

Sounds almost too good to be true to be able to just change the casette 11-27 to 11-32. Fingers crossed.

LongIslandTom

Yup, if you got the Ultegra GS rear derailleur you can definitely use the 11-32T cassette. Just make sure your chain is long enough.

Remember that going from a 27T cog to 32T cog is a difference of 5 teeth.. The chain needs to be long enough to accommodate the extra teeth on the new big cog. If your existing chain is too short, it will lock up the drivetrain when you accidentally crosschain into the big/big combination (and possibly damage your rear derailleur by stretching the cage too far forward).