Ultegra 12-30 cassette with a 6700 short cage rear mech?
Discussion
I've already bought the cassette, but I'm wondering if anyone can advise me if this set-up will work?
I've got a 2010 Trek 2.5 with a full Ultegra 6700 groupset and a short cage rear mech.
The cassette I'm running on it is a 12-27 set-up however a lot of the hills around my parts have 10-15% inclines and they are soul destroying on my current set-up.
I'm hoping the extra 3 teeth on the 12-30 will help somewhat however, will it work as a straight swap with my short cage Ultegra 6700 derailleur or will I have to replace that too?
I can't get any confirmation on this through forums I've traweled. It's really a mixed opinion. Has anyone on here tried the set-up and does it work ok without any shifting issues?
I've got a 2010 Trek 2.5 with a full Ultegra 6700 groupset and a short cage rear mech.
The cassette I'm running on it is a 12-27 set-up however a lot of the hills around my parts have 10-15% inclines and they are soul destroying on my current set-up.
I'm hoping the extra 3 teeth on the 12-30 will help somewhat however, will it work as a straight swap with my short cage Ultegra 6700 derailleur or will I have to replace that too?
I can't get any confirmation on this through forums I've traweled. It's really a mixed opinion. Has anyone on here tried the set-up and does it work ok without any shifting issues?
You'll probably have to put a few extra links into the chain (probably best to get a new one with a new cassette anyway) and it might leave your 10th or 11th gear a bit noisy.
Just make sure that you can get in the 30t on the cassette while on the top chainring without it smashing your rear mech to bits.
Just make sure that you can get in the 30t on the cassette while on the top chainring without it smashing your rear mech to bits.
The only thing you can do is try it, but I suspect not - a 27/28 is already stretching the capacity of a short cage mech, and I think a 30 is flat too big never mind the capacity:
First problem is whether the mech has enough clearance from the axle to allow the diameter of the 30t sprocket in there (imagine you put a front chainring in there - it would overlap the mech). You can gain some space by taking the b-screw out and putting it in backwards (which is how I run a 28), but I think a 30 will be a bridge too far. Put it on the wheel, put the wheel in and see..
Capacity wise, aside from probably wanting a longer chain, there's only a limited amount of slack that the mech can take up. IIRC it's calculated as big ring + big sprocket - small ring + small sprocket. Shimano's numbers are very conservative - you should never go big ring + big sprocket anyways... so you can push things a little there, just don't cross chain.
Really the correct answer is to fit a compact chainset. If you've already got a compact chainset and a 27.. sorry, but it's time to HTFU
First problem is whether the mech has enough clearance from the axle to allow the diameter of the 30t sprocket in there (imagine you put a front chainring in there - it would overlap the mech). You can gain some space by taking the b-screw out and putting it in backwards (which is how I run a 28), but I think a 30 will be a bridge too far. Put it on the wheel, put the wheel in and see..
Capacity wise, aside from probably wanting a longer chain, there's only a limited amount of slack that the mech can take up. IIRC it's calculated as big ring + big sprocket - small ring + small sprocket. Shimano's numbers are very conservative - you should never go big ring + big sprocket anyways... so you can push things a little there, just don't cross chain.
Really the correct answer is to fit a compact chainset. If you've already got a compact chainset and a 27.. sorry, but it's time to HTFU
Cheers for the feedback. The bike came as standard with a 12-27 and a compact chainset so this really is the only option I have. Trust me, the hills where I am are a nightmare and you can hit a 15% incline over about 2-3km quite often. I have to do it every time I go home and in the 35C heat, it's just too much. Even my personal trainer thinks I'm nuts taking on the hills but I haven't got much of a choice.
I've actually ordered a new chain as my old one is getting a little worn so I'll add a couple of extra links to help cope with the extra size of the 30 chainring.
What however is the B screw? I've seen this mentioned before but how does it work and where do I find it?
Also to add, whatever the outcome, when the parts arrive, I'll post the results on here.
I've actually ordered a new chain as my old one is getting a little worn so I'll add a couple of extra links to help cope with the extra size of the 30 chainring.
What however is the B screw? I've seen this mentioned before but how does it work and where do I find it?
Also to add, whatever the outcome, when the parts arrive, I'll post the results on here.
Just to add, this is one of the segments I'm struggling with on my short ride:
http://www.strava.com/activities/162637301/segment...
http://www.strava.com/activities/162637301/segment...
upsidedownmark said:
you should never go big ring + big sprocket anyways... so you can push things a little there, just don't cross chain.
That's not technically true. If it were how can they call group-sets 20 speed or 22 speed? The different in angle from one ring to the other is negligible.For what it's worth my local mechanic (40+ years in the trade) claims that running an 11t sprocket does more damage to the chain than using "top top"
Cage length doesn't *directly* impact the size of the sprocket you can run, but the medium and long cage mech's are built with the assumption that you're running bigger sprockets and larger gear ranges, so they put more space between the jockey wheel and the axle line.
The b-screw: If you look at the bike from the rear, you'll see a little screw that goes through the mech at the pivot point and presses up against the mech hanger. The tighter it is, the more it rotates the mech body backwards, which opens up (vertical) spacing between the top jockey wheel and the sprockets. It's normally set to keep them close but not touching. If you get the jockey wheel touching even with it fully in, you can 'fudge' a bit more tension by taking the mech off, threading the b-screw in from the other side - just far enough for it to be secure, then putting the mech back on with the b-screw effectively 'flipped'
Picture would probably help: http://i.imgur.com/35CrJUN.jpg (not flipped)
Chain sizing - rather than just add a link or two, do a bit of googling and set the length properly - IIRC parktool have a guide.
In terms of mech's there's naff all difference between any of the 9/10/11speed series..
10% should be fine on 34/27.. not sure about 35deg though, think I'd die sitting at a cafe All joking apart, are you fairly new to the cycling / training? You'd be surprised how quickly you get stronger if you are.
Next possibility is a triple (or possibly a cross crank? I don't know much about those, but I think they have < 34 chain rings...)
The b-screw: If you look at the bike from the rear, you'll see a little screw that goes through the mech at the pivot point and presses up against the mech hanger. The tighter it is, the more it rotates the mech body backwards, which opens up (vertical) spacing between the top jockey wheel and the sprockets. It's normally set to keep them close but not touching. If you get the jockey wheel touching even with it fully in, you can 'fudge' a bit more tension by taking the mech off, threading the b-screw in from the other side - just far enough for it to be secure, then putting the mech back on with the b-screw effectively 'flipped'
Picture would probably help: http://i.imgur.com/35CrJUN.jpg (not flipped)
Chain sizing - rather than just add a link or two, do a bit of googling and set the length properly - IIRC parktool have a guide.
In terms of mech's there's naff all difference between any of the 9/10/11speed series..
10% should be fine on 34/27.. not sure about 35deg though, think I'd die sitting at a cafe
All joking apart, are you fairly new to the cycling / training? You'd be surprised how quickly you get stronger if you are.Next possibility is a triple (or possibly a cross crank? I don't know much about those, but I think they have < 34 chain rings...)
Dixie said:
That's not technically true. If it were how can they call group-sets 20 speed or 22 speed? The different in angle from one ring to the other is negligible.
For what it's worth my local mechanic (40+ years in the trade) claims that running an 11t sprocket does more damage to the chain than using "top top"
Because there are 20/22 discreet gears. However, there is significant overlap. Same cadence (on a compact) will require about 4 sprockets to be dropped at the back when you go from the big ring to the small. Why on earth would run 'top-top' when you can run something near the middle of the cassette and the small ring - for one thing if you need another gear you can have it, without trying to drop the front ring under load and nutting yourself. Only reason I can see is the delusional 'big ring' bull**** For what it's worth my local mechanic (40+ years in the trade) claims that running an 11t sprocket does more damage to the chain than using "top top"
Either way, my point remains - shimano's numbers for gear range assume the worst case. You can push them quite significantly if you're willing to be sensible about the extremes within the overlap.
upsidedownmark said:
Cage length doesn't *directly* impact the size of the sprocket you can run, but the medium and long cage mech's are built with the assumption that you're running bigger sprockets and larger gear ranges, so they put more space between the jockey wheel and the axle line.
The b-screw: If you look at the bike from the rear, you'll see a little screw that goes through the mech at the pivot point and presses up against the mech hanger. The tighter it is, the more it rotates the mech body backwards, which opens up (vertical) spacing between the top jockey wheel and the sprockets. It's normally set to keep them close but not touching. If you get the jockey wheel touching even with it fully in, you can 'fudge' a bit more tension by taking the mech off, threading the b-screw in from the other side - just far enough for it to be secure, then putting the mech back on with the b-screw effectively 'flipped'
Picture would probably help: http://i.imgur.com/35CrJUN.jpg (not flipped)
Chain sizing - rather than just add a link or two, do a bit of googling and set the length properly - IIRC parktool have a guide.
In terms of mech's there's naff all difference between any of the 9/10/11speed series..
10% should be fine on 34/27.. not sure about 35deg though, think I'd die sitting at a cafe All joking apart, are you fairly new to the cycling / training? You'd be surprised how quickly you get stronger if you are.
Next possibility is a triple (or possibly a cross crank? I don't know much about those, but I think they have < 34 chain rings...)
Cheers for the tips. I'm fairly experienced at cycling. I'm out at least twice a week and I've done a few competitions and 130km tours but the ascents around where I live are relentless making my short training stints more than hard work. Annoyingly I have to stop at least twice to get my HR down so my first goal is to make it to the top of the above segment without stopping at all. I'm hoping the 30 chainring will help me get there.The b-screw: If you look at the bike from the rear, you'll see a little screw that goes through the mech at the pivot point and presses up against the mech hanger. The tighter it is, the more it rotates the mech body backwards, which opens up (vertical) spacing between the top jockey wheel and the sprockets. It's normally set to keep them close but not touching. If you get the jockey wheel touching even with it fully in, you can 'fudge' a bit more tension by taking the mech off, threading the b-screw in from the other side - just far enough for it to be secure, then putting the mech back on with the b-screw effectively 'flipped'
Picture would probably help: http://i.imgur.com/35CrJUN.jpg (not flipped)
Chain sizing - rather than just add a link or two, do a bit of googling and set the length properly - IIRC parktool have a guide.
In terms of mech's there's naff all difference between any of the 9/10/11speed series..
10% should be fine on 34/27.. not sure about 35deg though, think I'd die sitting at a cafe
All joking apart, are you fairly new to the cycling / training? You'd be surprised how quickly you get stronger if you are.Next possibility is a triple (or possibly a cross crank? I don't know much about those, but I think they have < 34 chain rings...)
I did consider a triple but that involves huge expense in the form of a new crank, front derailleur and shifter, plus the cost of getting it all fitted so I'm not particularly interested.
I'm also looking at changing my bike soon so I don't want to spend too much on upgrades with mine.
I've got the part ordered from Wiggle so I think once again, it's a pretty mixed opinion on whether it'll work or not. I'll get the cassette fitted myself but I'll probably take my bike into a shop to get the chain fitted correctly.
beanbag said:
upsidedownmark said:
Cage length doesn't *directly* impact the size of the sprocket you can run, but the medium and long cage mech's are built with the assumption that you're running bigger sprockets and larger gear ranges, so they put more space between the jockey wheel and the axle line.
The b-screw: If you look at the bike from the rear, you'll see a little screw that goes through the mech at the pivot point and presses up against the mech hanger. The tighter it is, the more it rotates the mech body backwards, which opens up (vertical) spacing between the top jockey wheel and the sprockets. It's normally set to keep them close but not touching. If you get the jockey wheel touching even with it fully in, you can 'fudge' a bit more tension by taking the mech off, threading the b-screw in from the other side - just far enough for it to be secure, then putting the mech back on with the b-screw effectively 'flipped'
Picture would probably help: http://i.imgur.com/35CrJUN.jpg (not flipped)
Chain sizing - rather than just add a link or two, do a bit of googling and set the length properly - IIRC parktool have a guide.
In terms of mech's there's naff all difference between any of the 9/10/11speed series..
10% should be fine on 34/27.. not sure about 35deg though, think I'd die sitting at a cafe All joking apart, are you fairly new to the cycling / training? You'd be surprised how quickly you get stronger if you are.
Next possibility is a triple (or possibly a cross crank? I don't know much about those, but I think they have < 34 chain rings...)
Cheers for the tips. I'm fairly experienced at cycling. I'm out at least twice a week and I've done a few competitions and 130km tours but the ascents around where I live are relentless making my short training stints more than hard work. Annoyingly I have to stop at least twice to get my HR down so my first goal is to make it to the top of the above segment without stopping at all. I'm hoping the 30 chainring will help me get there.The b-screw: If you look at the bike from the rear, you'll see a little screw that goes through the mech at the pivot point and presses up against the mech hanger. The tighter it is, the more it rotates the mech body backwards, which opens up (vertical) spacing between the top jockey wheel and the sprockets. It's normally set to keep them close but not touching. If you get the jockey wheel touching even with it fully in, you can 'fudge' a bit more tension by taking the mech off, threading the b-screw in from the other side - just far enough for it to be secure, then putting the mech back on with the b-screw effectively 'flipped'
Picture would probably help: http://i.imgur.com/35CrJUN.jpg (not flipped)
Chain sizing - rather than just add a link or two, do a bit of googling and set the length properly - IIRC parktool have a guide.
In terms of mech's there's naff all difference between any of the 9/10/11speed series..
10% should be fine on 34/27.. not sure about 35deg though, think I'd die sitting at a cafe
All joking apart, are you fairly new to the cycling / training? You'd be surprised how quickly you get stronger if you are.Next possibility is a triple (or possibly a cross crank? I don't know much about those, but I think they have < 34 chain rings...)
I did consider a triple but that involves huge expense in the form of a new crank, front derailleur and shifter, plus the cost of getting it all fitted so I'm not particularly interested.
I'm also looking at changing my bike soon so I don't want to spend too much on upgrades with mine.
I've got the part ordered from Wiggle so I think once again, it's a pretty mixed opinion on whether it'll work or not. I'll get the cassette fitted myself but I'll probably take my bike into a shop to get the chain fitted correctly.
Rocksteadyeddie said:
Why not change for a long cage mech? Will probably cost £40 and take all of ten minutes to change. The old one can be sold on Ebay to recoup much of the outlay.
Just been looking at the cost on Wiggle and they're not too expensive, however looking at the stats, it does clearly say the short cage (which I have) will accommodate a 30T:http://www.wiggle.co.uk/shimano-rd-6700-ultegra-ss...
Maybe it will be ok if adjusted correctly?
beanbag said:
Rocksteadyeddie said:
Why not change for a long cage mech? Will probably cost £40 and take all of ten minutes to change. The old one can be sold on Ebay to recoup much of the outlay.
Just been looking at the cost on Wiggle and they're not too expensive, however looking at the stats, it does clearly say the short cage (which I have) will accommodate a 30T:http://www.wiggle.co.uk/shimano-rd-6700-ultegra-ss...
Maybe it will be ok if adjusted correctly?
http://techdocs.shimano.com/media/techdocs/content...
Rocksteadyeddie said:
Unless you've got a known heart problem you may not be doing this correctly...
I'll welcome any suggestions but I never usually have such issues. My BPM will reach about 189, which I simply cannot keep up for more than a few minutes as my legs eventually give in. Trust me, the inclines are pretty horrific and they continue for about 4km (on this specific climb). If you reverse the route, you end up with a 24 degree climb for about a couple of hundred meters. It's gut-wrenching!I also think the 35C heat doesn't help much but I'll happily take any suggestions. I would generally say I'm quite fit. I've back off quite a bit in the past months but until recently, I was cycling on average about 200+ miles each week and regularly achieve about 2500m (8,000ft) of ascent over my longer rides.
Fair points on the triple.. Try the 30, and if it doesn't fit just buy a medium/long cage mech as someone else said.
Chain is easy - link here (largest to largest method) http://www.parktool.com/blog/repair-help/chain-len...
And yeah, unless you have medical issues, just ignore the heart rate - perhaps even cover it and keep climbing. If your legs give out, that's a whole other thing. The thing is to pace yourself to complete, in fairness, that's really where having enough gears comes in..
Chain is easy - link here (largest to largest method) http://www.parktool.com/blog/repair-help/chain-len...
And yeah, unless you have medical issues, just ignore the heart rate - perhaps even cover it and keep climbing. If your legs give out, that's a whole other thing. The thing is to pace yourself to complete, in fairness, that's really where having enough gears comes in..
upsidedownmark said:
Fair points on the triple.. Try the 30, and if it doesn't fit just buy a medium/long cage mech as someone else said.
Chain is easy - link here (largest to largest method) http://www.parktool.com/blog/repair-help/chain-len...
And yeah, unless you have medical issues, just ignore the heart rate and keep climbing. It never gets easier, you just get faster
I've never thought I've done it wrong! Chain is easy - link here (largest to largest method) http://www.parktool.com/blog/repair-help/chain-len...
And yeah, unless you have medical issues, just ignore the heart rate and keep climbing. It never gets easier, you just get faster
I do push myself beyond what appears to be most people but there is a point when your legs simply give....
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