Replacing A Cassette on a Bike

chrismilbourne94

Hi, I'm going to be buying a new bike soon, and I'm probably going to go for the Cannondale Synapse Carbon 5 105 (http://www.evanscycles.com/products/can ... e-ec042926). The only thing is, the Shimano 105 cassette is a 10 speed with 11-28 teeth. I come from a running background, so I have lean runner legs (actually, by lean I mean puny, compared to a cyclist anyway). Joking aside, I'm moving to a city that is notoriously hilly (any guesses where ?), so will be doing a lot of climbing. Here lies my problem. I want to swap the cassette for the Shimano Ultegra 6800 11 speed, which comes with 11 - 32 teeth. But, I'm not 100% sure on the other components that will need replacing. I'm pretty certain that I will need to replace the chain with an 11 speed (the Ultegra 6800 is only £20 so that's not a problem.)

Would I have to also replace the chainset? The one that comes as standard with the bike is the FSA Gossamer Pro, which has 50x34 tooth chainrings. This is fine, but would it have to be changed in light of the fact that there will now be an 11 speed casette/chain?

Also, would the shifters have to be changed to 11 speed shifters, such as these, or is there some way to use the 10 speed shifters? http://www.wiggle.co.uk/shimano-ultegra ... uble-6800/


Thanks in advance

rolf_f

With a compact 50-34 chainset a 28 cassette is pretty low geared anyway. And if you are lightweight runner I would have thought you'll become a good climbing cyclist.

So best just stick with the bike as it is for now and worry about changing things when you have got used to it and understand what is involved! Buying a new bike and immediately talking about changing it from 10 to 11 speed means you are buying the wrong bike in the first place!

paul2718

You've linked to last years model on the Evans site, and it appears they have none to sell.

More pertinently it makes no sense to buy a new bike equipped with 10 speed 105 and piecemeal upgrade to 11 speed Ultegra. You would need to ensure that the supplied rear wheel was 11 speed compatible. Then change the cassette, chain and shifter(s). And possibly the rear derailleur. Cranks will be fine.

Even more pertinently 34x28 is already a very low gear, if you are at all fit then it would be unusual to have serious difficulty on anything other than long 'stunt' climbs.

I would either live with the 10 speed, go for a bike that comes with Ultegra 11 speed, or wait for next season when 105 goes 11 speed.

And after all that the 11-32 cassette, even 11 speed, is very wide. It's a big compromise on normal use and seems, to me, to be mostly a marketing exercise to hasten the removal of the apparent need for triples, and softening up the market for Di2 everything. Di2 is fabulous, but that's another story.

Paul

markhewitt1978

chrismilbourne94 wrote:

Hi, I'm going to be buying a new bike soon, and I'm probably going to go for the Cannondale Synapse Carbon 5 105 (http://www.evanscycles.com/products/can ... e-ec042926). The only thing is, the Shimano 105 cassette is a 10 speed with 11-28 teeth. I come from a running background, so I have lean runner legs (actually, by lean I mean puny, compared to a cyclist anyway). Joking aside, I'm moving to a city that is notoriously hilly (any guesses where ?)

Could be any number of cities.

11-28 is a pretty versatile gearset and most won't have a problem with climbing with that. It's a fairly standard chainset for getting up hills especially with a compact chainset.

, so will be doing a lot of climbing. Here lies my problem. I want to swap the cassette for the Shimano Ultegra 6800 11 speed, which comes with 11 - 32 teeth. But, I'm not 100% sure on the other components that will need replacing. I'm pretty certain that I will need to replace the chain with an 11 speed (the Ultegra 6800 is only £20 so that's not a problem.)

Would I have to also replace the chainset? The one that comes as standard with the bike is the FSA Gossamer Pro, which has 50x34 tooth chainrings. This is fine, but would it have to be changed in light of the fact that there will now be an 11 speed casette/chain?

Also, would the shifters have to be changed to 11 speed shifters, such as these, or is there some way to use the 10 speed shifters? http://www.wiggle.co.uk/shimano-ultegra ... uble-6800/

The chainset is about the only thing you won't need to change. You will need at least, new STi shifters, you could get away with one but it would look stupid, new front mech to match, rear mech, chain, cassette.

But the biggie is that you'll have to make sure your wheels can take 11 speed cassettes, if not you'll need a new rear wheel too.

My best advice is - don't! 105 is a perfectly good groupset you don't need to go replacing it, especially since you can buy a 12-30 cassette for about £15 which will give you a plenty low gear - only 2 away from a 32 anyway.

ai_1

You're basically talking about changing most of the groupset to Ultegra 6800 which makes no sense on a new bike.
I think you can get a cassette with 30t for 10 speed 105 which will get you half way there just by changing the cassette which is simple and cheap by comparison.

paul2718 wrote:

.....Even more pertinently 34x28 is already a very low gear, if you are at all fit then it would be unusual to have serious difficulty on anything other than long 'stunt' climbs.....

....And after all that the 11-32 cassette, even 11 speed, is very wide. It's a big compromise on normal use and seems, to me, to be mostly a marketing exercise to hasten the removal of the apparent need for triples, and softening up the market for Di2 everything. Di2 is fabulous, but that's another story.

It's not just about fitness, weight is equally relevant. Until recently I'd have struggled on a lot of climbs even with a 34x28. I'm about 86kg and was a few kg heavier. Not massive but heavy enough for a 1.78m (5'10") cyclist. Although I've been pretty fit for the last couple of years, it's only now that I've lost some weight combined with a new much lighter bike that I'm confident I can live with a 34x28 smallest gear. Heavier riders DO need significantly smaller gears than light riders of comparable fitness, a fact many experienced cyclists seem to scoff at. As an engineer it's very clear to me how weight effects the power requirements for getting up a hill. It's not a matter of opinion but fact that heavier riders will have to ride slower on hills and therefore will either need to grind away at very low cadence when it gets steep or will need smaller gears than their counterparts.

Having said all that a runner with puny legs is likely to be slim in general and therefore well suited to climbing on the bike. It's not the legs that are typically the limiting factor for cycling on hills but the heart and lungs (which don't scale up in proportion to muscle bulk).

You will likely be okay with a 34-28 combo (or 34-30 if you can change just the cassette) but if you're worried you need 34-32 then buy a bike with Ultegra 6800 from the outset.

andy9964

Before getting my bike, my first roadie. I'd mentally spent around £100 on a new saddle after worrying about how uncomfortable it would be
2500 miles later, my bike still has the original saddle on it.

If you go for a 10 speed, give it a chance before making any decisions.

Maybe swapping one or two of the rings on the cassette might be possible

plodder73

I have a 105 with a 10 speed 11/32 cassette. I don't find any issue with the gaps between gears. Living where I am I would rather have that than try and stuggle with a11/28. Some people will always say you hold be able to get up anything on a 28 or 25 well I can't but I can get up anything with my 32. In actual fact I very rarely use it but on the few occasions I have the alternative would have been to stop.

chrisaonabike

Try the 11-28, and then (as I did) just swap the cassette for a cassette with 30T. I went from 12-28 to 12-30 (Tiagra) when I changed the chain, and it made life a lot better.

If you still want lower after you've tried 34/30, then you can consider changing all the bits, but it's really not worth considering changing before you've even bought the bike.

Don't listen to all the guys that go on about 28 already being a very low gear. That's just them telling you that they find it easy, which is no bleedin' good to you at all. If you have lower, you don't need to use it, but if you don't, you don't have the option.

I could have struggled on with 28, but my knees were hurting a bit after hills, and changing the cassette gave me that little bit extra. Thoroughly recommend it - and a cassette change is by far the cheapest way of getting a lower gear.

plodder73

Yes agree with Chris above. I tried the 12/30 tiagra from my 11/32, but the 12/30 doesn't have 28 just 27 so found myself in the bottom 30 gear much more and then didnt have my last resort gear.

markhewitt1978

ChrisAOnABike wrote:

Don't listen to all the guys that go on about 28 already being a very low gear. That's just them telling you that they find it easy, which is no bleedin' good to you at all. If you have lower, you don't need to use it, but if you don't, you don't have the option.

Yeah but to be fair the OP hasn't even tried the supplied 28 to know if it's low or not. Fair enough after a couple of months he's struggling and wants lower gears, but no point in changing before that because 28 is a low gear for many.

paul2718

Don't listen to all the guys that go on about 28 already being a very low gear. That's just them telling you that they find it easy, which is no bleedin' good to you at all.

The OP states he is coming from a running background and has 'lean runner' legs. So he's not an over-weight ex-smoker taking his first exercise for 30 years.

In that context 34x28 is a very low gear and doesn't need pre-emptively changing for something even lower.

Paul

slowbike

ChrisAOnABike wrote:

Don't listen to all the guys that go on about 28 already being a very low gear. That's just them telling you that they find it easy, which is no bleedin' good to you at all. If you have lower, you don't need to use it, but if you don't, you don't have the option.

Don't listen to the guys going on about a 30f/34r being the optimal gear selection, fat lot of good crawling up a 4% incline at 3.5mph with your legs whizzing away at 100rpm wishing you had stuck with your original cassette ...

I have just once changed an original cassette for a different one - my wifes bike came with a 25-11 cassette and compact chainrings - we were off to do a hilly ride so promptly swapped for a 30-12 cassette that I knew suited her as she'd used it previously. Once the hills are done with or she stops using the 30 cog I'll swap it back to a 28-11 or 27-12.
You can always have more than 1 cassette!

ic.

Just swap the cassette out. No need to go swapping everything to 11 speed just to gain a 32t gear.

Simply buy a SRAM Apex 12-32 cassette. See if your rear mech will work with it, and if not buy a WiFli rear mech too. Far cheaper

plodder73

paul2718 wrote:

Don't listen to all the guys that go on about 28 already being a very low gear. That's just them telling you that they find it easy, which is no bleedin' good to you at all.

The OP states he is coming from a running background and has 'lean runner' legs. So he's not an over-weight ex-smoker taking his first exercise for 30 years.

In that context 34x28 is a very low gear and doesn't need pre-emptively changing for something even lower.

Paul

Yes good advice, try it first see how you get on. I have probably 3 stone more to lumber up the hills. You may well be fine, also I don't stand when climbing, if I could manage a sustained period of climbing I might manage with a smaller cassette. Give it a try and new cassette is only £15 or so.

rolf_f

Slowbike wrote:

Don't listen to the guys going on about a 30f/34r being the optimal gear selection, fat lot of good crawling up a 4% incline at 3.5mph with your legs whizzing away at 100rpm wishing you had stuck with your original cassette ...

He can't listen to that as nobody (aside from your good self) has so far mentioned 30f/34r!

And, to be ultrageek, to do 3.5 mph at 100rpm, assuming a 34 front, you'd need a cassette with a 75 tooth sprocket on the back and I don't think even SRAM can accomodate that!

ai_1

paul2718 wrote:

Don't listen to all the guys that go on about 28 already being a very low gear. That's just them telling you that they find it easy, which is no bleedin' good to you at all.

The OP states he is coming from a running background and has 'lean runner' legs. So he's not an over-weight ex-smoker taking his first exercise for 30 years.

In that context 34x28 is a very low gear and doesn't need pre-emptively changing for something even lower.

I hope you're not implying that I'm equivalent to an over-weight ex-smoker taking my first exercise in 30 years! :x
I assure you I'm not! I'm only marginally overweight, have never smoked, I'm neither an elite cyclist nor runner but reasonably competent at both and have been holding my own in duathlons and adventure races for a couple of years now and riding sportives of up to 200km. I do a fair amount of riding in the hills with a few longish hills (2.5km-4km) of 9%-13% gradient and the toughest getting up to about 18% gradient. For me, on these hills, 34x28 is sufficient but only just. It's not a particularly easy ratio.
34x28 is a low gear compared to 39x25 but that doesn't mean it's low enough. The previous poster is quite right to advise against listening to those saying 34x28 is a very low gear just as he shouldn't listen to me if I said he needed a lower one.

Slowbike wrote:

ChrisAOnABike wrote:

Don't listen to all the guys that go on about 28 already being a very low gear. That's just them telling you that they find it easy, which is no bleedin' good to you at all. If you have lower, you don't need to use it, but if you don't, you don't have the option.

Don't listen to the guys going on about a 30f/34r being the optimal gear selection, fat lot of good crawling up a 4% incline at 3.5mph with your legs whizzing away at 100rpm wishing you had stuck with your original cassette ...

I hope you were taking poetic license with your figures in this example because they are complete fiction. Also as you know very well, the bigger gears don't disappear once you have a small one available, the gaps just get slightly bigger! Smaller gaps are nice but not essential, on the other hand a small gear can be essential if you want to avoid walking - it's never happened to me yet but that's because I've always given myself the gear I need. I have passed numerous people walking up hills during sportives because they're following the standard advice on gear ratios.

As for your figures - I think you'll find that 3.5mph in 34x30 will leave you with a cadence of about 38rpm (not whizzing at 100rpm as you would have us believe) which is VERY low by anyone's standards but then 3.5mph is fairly unrealistic as balance will be getting tricky at that point. So let's look at the figures to illustrate the difference between some typical ratios in your example and in what I think is a realistic example on a steep slope:

Your example first:
Speed: 5.6km/h (3.5mph)
34x30 - 38rpm
34x28 - 36rpm
34x25 - 32rpm
Unrealistic example but even so, if 3.5mph is all you can manage then the 34x30 option is the best of a bad lot.

Now something more realistic for a steep slope and a moderately heavy but fit rider (approximately what I'd do on a long 10%-12% climb)
Speed: 10km/h (6.25mph)
34x30 - 69rpm
34x28 - 64rpm
34x25 - 57rpm
Correct me if I'm wrong but none of those seem like excessively high cadence figures to me. In fact they all look lower than ideal. I can live with cadence as low as about 50 but I'll probably be getting out of the saddle at that point.

Can you tell me what sort of speed you do up the steepest slopes you tackle and in what gear and we'll see what cadence you really think is acceptable?

P.S.
Just spotted that you in fact said 30f/34r which would be 30-34 as I've been writing it. So one more example:
Your example corrected:
Speed: 5.6km/h (3.5mph)
30x34 - 49rpm
34x28 - 36rpm
34x25 - 32rpm
Even with this much lower gear ratio that no-one was suggesting, it still ends up being the best of the bunch for this example and nowhere near "legs whizzing away at 100rpm!"

slowbike

Rolf F wrote:

Slowbike wrote:

Don't listen to the guys going on about a 30f/34r being the optimal gear selection, fat lot of good crawling up a 4% incline at 3.5mph with your legs whizzing away at 100rpm wishing you had stuck with your original cassette ...

He can't listen to that as nobody (aside from your good self) has so far mentioned 30f/34r!

And, to be ultrageek, to do 3.5 mph at 100rpm, assuming a 34 front, you'd need a cassette with a 75 tooth sprocket on the back and I don't think even SRAM can accomodate that!

Nah - you got it the wrong way - he obviously needs a triple (30t front) and a 34-?? cassette (34 back) ... because everybody knows that the lower the gear the easier it is to peddle ...

Anyway - it was a pistake ..

rolf_f

Slowbike wrote:

Rolf F wrote:

Slowbike wrote:

Don't listen to the guys going on about a 30f/34r being the optimal gear selection, fat lot of good crawling up a 4% incline at 3.5mph with your legs whizzing away at 100rpm wishing you had stuck with your original cassette ...

He can't listen to that as nobody (aside from your good self) has so far mentioned 30f/34r!

And, to be ultrageek, to do 3.5 mph at 100rpm, assuming a 34 front, you'd need a cassette with a 75 tooth sprocket on the back and I don't think even SRAM can accomodate that!

Nah - you got it the wrong way - he obviously needs a triple (30t front) and a 34-?? cassette (34 back) ... because everybody knows that the lower the gear the easier it is to peddle ...

Anyway - it was a pistake ..

I know. But I think you upset Ai-1!

I'm now going to sit back and watch everyone continuing to repeat what I said in the first reply to the OP only using 3 times as many words!

slowbike

Ai_1 wrote:

Slowbike wrote:

Don't listen to the guys going on about a 30f/34r being the optimal gear selection, fat lot of good crawling up a 4% incline at 3.5mph with your legs whizzing away at 100rpm wishing you had stuck with your original cassette ...

I hope you were taking poetic license with your figures in this example because they are complete fiction. Also as you know very well, the bigger gears don't disappear once you have a small one available, the gaps just get slightly bigger! Smaller gaps are nice but not essential, on the other hand a small gear can be essential if you want to avoid walking - it's never happened to me yet but that's because I've always given myself the gear I need. I have passed numerous people walking up hills during sportives because they're following the standard advice on gear ratios.

Now something more realistic for a steep slope and a moderately heavy but fit rider (approximately what I'd do on a long 10%-12% climb)
Speed: 10km/h (6.25mph)
34x30 - 69rpm
34x28 - 64rpm
34x25 - 57rpm
Correct me if I'm wrong but none of those seem like excessively high cadence figures to me. In fact they all look lower than ideal. I can live with cadence as low as about 50 but I'll probably be getting out of the saddle at that point.

Can you tell me what sort of speed you do up the steepest slopes you tackle and in what gear and we'll see what cadence you really think is acceptable?

P.S.
Just spotted that you in fact said 30f/34r which would be 30-34 as I've been writing it. So one more example:
Your example corrected:
Speed: 5.6km/h (3.5mph)
30x34 - 49rpm
34x28 - 36rpm
34x25 - 32rpm
Even with this much lower gear ratio that no-one was suggesting, it still ends up being the best of the bunch for this example and nowhere near "legs whizzing away at 100rpm!"

Poetic licence - completely - it seems that as soon as someone suggests (how can anyone recommend without knowing the person, their fitness or where they intend to ride?!) a gear then someone else rubbishes it and comes in lower ... so I thought i'd just take it to the extreme - with a 30/39/50 setup on my CX I could get a 34/11 and run a 30/34 .. although I couldn't imagine any climb that I'd want to tackle requiring that combination - if you're into mountain climbing then it may be handy !

Personally I prefer the grind - I've tried spinning up hills, but it's not happening - It seems my legs would rather drop down to 60-70rpm and push hard- others may like to spin - purely personal preference!

drlodge

I could have used a 30x34 going up Great Dun Fell. 34x29 just wasn't low enough with my knackered legs going up 20% for ages...

paul2718

I hope you're not implying that I'm equivalent to an over-weight ex-smoker taking my first exercise in 30 years!

I was implying that giving the OP advice appropriate for an over-weight ex-smoker taking their first exercise for 30 years wasn't particularly helpful, given they told us a little about themselves.

For the OP, if 34x28 actually proves too hard, then change it. For our mythical fat smoker, start with a triple or a 34x32 and go from there. It doesn't seem that controversial.

I don't know whether the trend to ever lower gears as standard is customer or manufacturer driven. It is quite odd. Take http://www.scott-sports.com/gb/en/produ ... t-20-Bike/ for example, a 'race' geometry bike with 34x30 as its lowest gear. I wonder who it is aimed at.

Paul

ai_1

Slowbike - Didn't realise you were kidding because I misread the gear ratio you suggested in the first place. Only spotted it when I'd finished my post. Oops! Since I'd written all that I posted it anyway! The info's correct regardless, I hope.

I actually have used a gear not far from that. My bike for just over 3 years has been a Specialised Tricross: Sport Triple. It originally had 50/39/30 at the front and 11-32 at the back.
http://www.specialized.com/gb/gb/bikes/ ... iple#specs

I used it stock for a few months in early 2011 and then gradually switched out parts starting with the cassette and tyres then moving on to the wheels, stem and bars to end up with essentially a typical road bike geometry and set-up. I use either a 12-23 or 12-27 cassette depending on the terrain and whether I get around to switching cassettes before a ride. Anyway I initially rode it with a 30-32 small gear which got me up 10%+ slopes when I was a little on the chubby side and much less fit than I am today. Last year I threw back on the original wheels and tyres for some gravel track riding on a weekend away and just happened to spot a steep hill on a side road that took my fancy. I hadn't bothered to switch cassettes before heading off since it was supposed to be a fun ride with some non-cyclist friends who were riding all sorts of bikes, so I had the old 11-32 on it.
Anyway, the side road turned out to be the steepest hill I'd ever attempted. According to my Garmin and the OS maps it maxed out at around 25% half way up a ~1.5km climb. I'm not at all sure I could have done it with my usual pretty small gear of 30-27 but the unusually small 30-32 did the trick! Now that doesn't mean I'd recommend such a gear. It's rarely needed and on a 9 speed cassette it leaves pretty big gaps. But when needed, big gears have their place and for beginners especially, smaller gears can be much more important than small gaps.

ai_1

paul2718 wrote:

I hope you're not implying that I'm equivalent to an over-weight ex-smoker taking my first exercise in 30 years!

I was implying that giving the OP advice appropriate for an over-weight ex-smoker taking their first exercise for 30 years wasn't particularly helpful, given they told us a little about themselves.

Didn't recommend it. Said it was available if he thought it was appropriate and shouldn't be ignored because others told him what was appropriate.
On that note: How are you qualified to decide what's appropriate to an overweight ex-smoker taking their first exercise in 30 years. It's was an ignorant and unhelpful comment which is why I take offence. There are plenty people far from that description who may want that very setup. For example my brother who is a life long runner of typical pro-cyclist proportions (same height as me but only 65kg versus my ~85kg). He's a pretty impressive athlete on foot or on the bike and flies up hills, leaving me in the dust but he does it with very high cadence. Why? Because he has an old knee injury from running that gets aggravated from grinding up hills.

paul2718 wrote:

I don't know whether the trend to ever lower gears as standard is customer or manufacturer driven. It is quite odd. Take http://www.scott-sports.com/gb/en/produ ... t-20-Bike/ for example, a 'race' geometry bike with 34x30 as its lowest gear. I wonder who it is aimed at.

I suspect the trend to ever lower gears is entirely customer driven and due to the fact that large sprocket counts have removed most of the compromise from using a wide range cassette. When bikes had 5, 6, 7 or 8 sprockets you had to choose carefully what ratios you needed. With 9, 10 and 11 sprockets it's possible to cover ever broader ratio ranges without any excessive gaps. You can put on a do everything cassette, or if you're pushing for top performance on flatter terrain you can go for minimal gear spacing. It's probably the single most significant improvement in bikes over the last 30 years.
No mystery!

paul2718

Said it was available if he thought it was appropriate and shouldn't be ignored because others told him what was appropriate.

Very useful, but the OP doesn't know if he needs it or not.

How are you qualified to decide what's appropriate to an overweight ex-smoker taking their first exercise in 30 years. It's was an ignorant and unhelpful comment which is why I take offence.

You have no reason at all to take offence. I invented this particular smoker so I am confident he needs a 34x30 or 34x32. Or preferably a triple.

I hope the OP can find the bike he wants, make sense of the possibilities on offer, and adjust the gearing in the light of experience.

Paul

slowbike

Ai_1 wrote:

Slowbike - Didn't realise you were kidding because I misread the gear ratio you suggested in the first place. Only spotted it when I'd finished my post. Oops! Since I'd written all that I posted it anyway! The info's correct regardless, I hope.

I actually have used a gear not far from that. My bike for just over 3 years has been a Specialised Tricross: Sport Triple. It originally had 50/39/30 at the front and 11-32 at the back.
http://www.specialized.com/gb/gb/bikes/ ... iple#specs

I used it stock for a few months in early 2011 and then gradually switched out parts starting with the cassette and tyres then moving on to the wheels, stem and bars to end up with essentially a typical road bike geometry and set-up. I use either a 12-23 or 12-27 cassette depending on the terrain and whether I get around to switching cassettes before a ride. Anyway I initially rode it with a 30-32 small gear which got me up 10%+ slopes when I was a little on the chubby side and much less fit than I am today. Last year I threw back on the original wheels and tyres for some gravel track riding on a weekend away and just happened to spot a steep hill on a side road that took my fancy. I hadn't bothered to switch cassettes before heading off since it was supposed to be a fun ride with some non-cyclist friends who were riding all sorts of bikes, so I had the old 11-32 on it.
Anyway, the side road turned out to be the steepest hill I'd ever attempted. According to my Garmin and the OS maps it maxed out at around 25% half way up a ~1.5km climb. I'm not at all sure I could have done it with my usual pretty small gear of 30-27 but the unusually small 30-32 did the trick! Now that doesn't mean I'd recommend such a gear. It's rarely needed and on a 9 speed cassette it leaves pretty big gaps. But when needed, big gears have their place and for beginners especially, smaller gears can be much more important than small gaps.

I also have the tri-cross - same gear ratio as you - I quickly changed the cassette for a 23-11 as I never used the 30/32 combo. I've even towed a trailer with a child in it up a dirt trail (up ... the others had to stop to get their breath) and didn't need the bottom gear - not far off, but not quite.

The issue I find with wide range cassettes is that it's harder to get a comfortable gear on the flat - that is why I now choose a cassette that fits the majority of my riding rather than the exceptions.

the larger cassettes seem to run down to the smallest cogs - which is a bit odd really, as if you need such a low gear to go up then why (as a beginner) do you need such a high gear down the other way? IMHO it'd be better to cut the range short and keep the ratios a little closer together.

Barbarossa

2 pages and no one has actually answered the question!

10 speed and 11 speed are not compatible but there are 11-32 10 speed cassettes in the Shimano XT or SRAM PG 1050 ranges which will suit your 105 shifters. If the rear derailleur has a short cage (most likely), you will need to change it for a medium cage derailleur, you will also need a longer chain.

In all, this is going to cost around £70 in bit plus the cost of tools to change the cassette. I would try the 50-34 / 11-28 setup before changing things, you will probably be surprised how strong runner's legs are compared to those of cyclists!

Mad_Malx

Barbarossa wrote:

2 pages and no one has actually answered the question!

I think we've scared the OP off anyway.

General consensus is try your 11-28, then change the cassette to another 10 speed if 28 isn't enough.
Not many noobs (and even old hands) really need the 11 very much, even with a 50 up front, unless you have long sweeping descents or ride in fast groups. If you have the option, a 12-28 (available in tiagra for about £15) or 12-30 (in ultegra for £35) will be better more useful because the jumps will be smaller.

Edit - there might be a problem with the 30 (derailleur cage), but it'll probably work.

ai_1

Slowbike wrote:

the larger cassettes seem to run down to the smallest cogs - which is a bit odd really, as if you need such a low gear to go up then why (as a beginner) do you need such a high gear down the other way? IMHO it'd be better to cut the range short and keep the ratios a little closer together.

Agreed. Had this very discussion on another thread the other day. I'd much rather have a 12-28 or 12-30 than an 11-28. I can spin fast enough to reach just in excess of 80km/h with 50/12 on those occasional descents where its safe(ish) to do so. There are times when I do use 50/11 if available but it's never going to be a big deal not to have it. The same is not true at the other end if the cassette.
It's very irritating that the new Ultegra 6800 that's on my new bike only has one cassette in the range with a 12t smallest sprocket and I think that's a 12-25. If I want a 12-28 or similar I'd need to buy two cassettes and use the botom end from one and the top end from the other.

paul2718

Barbarossa wrote:

2 pages and no one has actually answered the question!

I think posts 2, 3, 4 pretty much covered it...

In all, this is going to cost around £70 in bit plus the cost of tools to change the cassette. I would try the 50-34 / 11-28 setup before changing things, you will probably be surprised how strong runner's legs are compared to those of cyclists!

Exactly. You'll be in trouble now from the weaker of leg.

The OP doesn't have the bike yet. Perhaps it was a clever troll.

Paul

Slo Mo Jones

As an overweight smoker, I'd like to add that I find a 28 to be fine except on anything ramping up to 15%+.

Many thanks.

Slo Mo Jones

Oh, and Dr Lodge - is that you in your profile picture?

You look like a thumb that someone has drawn a smiley face on. Good work.