struggling with choosing new groupset
Discussion
Hi all - I'm currently building a roadbike. I've ridden my MTB (standard Kona explosif, with knobblies etc) on the road for general exercise for the past couple of years. Now wanting to do some longer rides, so thought a roadbike was better. The MTB does get difficult after about 1.5 hrs in the saddle - although I can average 17.5-18mph. I know about rule 5, but still think a roadbike makes better sense for long rides 
.
So I have a nice frame and am looking to put a groupset on - I will be going to the shop on the weekend to talk to them about the options and have done some reading, but would value your thoughts too.
We live in a fairly flat area, but I do want to do some hills too (thinking Peak district when I'm a bit fitter). I'm 5'11" and weigh 12st 12lb. I prefer higher cadences to pushing heavy gears.
Now onto the groupset - crank length - I believe the 172.5mm suits most people, so this is likely what I'll be going for. I understand that the slightly longer cranks give more leverage, but also put more stress on the knees.
As far as chainsets go - my MTB is 28/38/48. I usually ride on 38, but on flat bits and downhill use the 48. I can spin it out down hill, but that's not often
. Now bear in mind that it's on a MTB with 2.25" knobbly tyres, so the rolling resistance on my new bike will be much less, so speed should be a lot better (and easier to maintain).
So, do I go compact and get the 34/50 - I'm worried the 34 will be too low, as the 38 on the MTB is easy to spin out, even on the flat in the smallest cog on the cassette (not sure what size that is though)
Or do I get the 39/53??
I was thinking of a 12/25 to start and know that the cassette is far easier (and cheaper) to replace than the chainset.
If I got the 34/50 chainset, I could get the 11/23 cassette
or I could get a larger cassette with the 39/53 chainset.
Well - that's it, in a (not so small) nutshell - please let me know what you think.
Thank you
.So I have a nice frame and am looking to put a groupset on - I will be going to the shop on the weekend to talk to them about the options and have done some reading, but would value your thoughts too.
We live in a fairly flat area, but I do want to do some hills too (thinking Peak district when I'm a bit fitter). I'm 5'11" and weigh 12st 12lb. I prefer higher cadences to pushing heavy gears.
Now onto the groupset - crank length - I believe the 172.5mm suits most people, so this is likely what I'll be going for. I understand that the slightly longer cranks give more leverage, but also put more stress on the knees.
As far as chainsets go - my MTB is 28/38/48. I usually ride on 38, but on flat bits and downhill use the 48. I can spin it out down hill, but that's not often
. Now bear in mind that it's on a MTB with 2.25" knobbly tyres, so the rolling resistance on my new bike will be much less, so speed should be a lot better (and easier to maintain). So, do I go compact and get the 34/50 - I'm worried the 34 will be too low, as the 38 on the MTB is easy to spin out, even on the flat in the smallest cog on the cassette (not sure what size that is though)
Or do I get the 39/53??
I was thinking of a 12/25 to start and know that the cassette is far easier (and cheaper) to replace than the chainset.
If I got the 34/50 chainset, I could get the 11/23 cassette
or I could get a larger cassette with the 39/53 chainset.
Well - that's it, in a (not so small) nutshell - please let me know what you think.
Thank you
Compact + 11-25.
Unless you're very precious about gaps, that gives you more top end than 53/39 with a 12, and plenty of climbing.
I'd try to get a 50/36 compact if I was buying, though they're more rare (or just replace the ring), as far as I'm concerned the main problem with 50/34 is too big a gap.
WRT crank length, size to your leg length - google for (a lot) of information - it's more about the angles your knees will need to cope with between top and bottom of stroke. Leverage sounds intuitive, but is irrelevant - your gears control the loading..
Unless you're very precious about gaps, that gives you more top end than 53/39 with a 12, and plenty of climbing.
I'd try to get a 50/36 compact if I was buying, though they're more rare (or just replace the ring), as far as I'm concerned the main problem with 50/34 is too big a gap.
WRT crank length, size to your leg length - google for (a lot) of information - it's more about the angles your knees will need to cope with between top and bottom of stroke. Leverage sounds intuitive, but is irrelevant - your gears control the loading..
If you use the 38T on the flat - must be an old bike! - then I'd definitely recommend you go for a 34/50 compact chainset, especially if you plan on riding in the Peaks.
I'd also suggest a 12-25 cassette will be best as it will give a nice low gear for the steep stuff but only two tooth gaps between the larger three sprockets.
I'd also suggest a 12-25 cassette will be best as it will give a nice low gear for the steep stuff but only two tooth gaps between the larger three sprockets.
thanks all-that's very helpful and yes, the MTB is about 8-9 yrs old .
sounds like the compact chainset 34/50 with a 11 (or12) - 25 cassette will be right for me. Sadly the shop is out of the 172.5mm cranks with the compact chainset (and the British Std BB) - so we'll see when they can get some more in.
Many thanks again
.sounds like the compact chainset 34/50 with a 11 (or12) - 25 cassette will be right for me. Sadly the shop is out of the 172.5mm cranks with the compact chainset (and the British Std BB) - so we'll see when they can get some more in.
Many thanks again
Regardless of what you choose, you will almost certainly find a gear for every situation on a regular ride and on the rare occassions that you dont, you will just have to grin and bear it, shout at the hills and apply a healthy dose of MTFU...
Unless you are purposely finding the biggest hills in the Country, you shouldnt have too much of a problem with 11-25 and a compact and good climbing technique is worth a few more teeth at the back anyway.
Unless you are purposely finding the biggest hills in the Country, you shouldnt have too much of a problem with 11-25 and a compact and good climbing technique is worth a few more teeth at the back anyway.
One of the biggest issues with overly long (relative to leg length) cranks is over rotation of the hip. As in if the crank arm is too long, when it is at the 6 o'clock postion, the arm at the top (minute arm if you will) could be pushing you're hip and leg out. Its probably more an issue for shorter riders though, as standard crank arms are around 170-172 (I'm 5'7", 30" leg so ride a 165).
Anyway, if you are choosing a new group set are you looking for a 10 or 11 speed cassette? You could go 11-28 in Campag or Siminao 11 speed? I've recently switched from "compact" to 53/39 with an 11-28 casette, and I'm very happy (my comfortable cadence range is still 85-95); my climbing is a lot better; and gives me what I want on the flats and what I need on climbs. That saying, better bike, wheels and engine who knows!
Anyway, if you are choosing a new group set are you looking for a 10 or 11 speed cassette? You could go 11-28 in Campag or Siminao 11 speed? I've recently switched from "compact" to 53/39 with an 11-28 casette, and I'm very happy (my comfortable cadence range is still 85-95); my climbing is a lot better; and gives me what I want on the flats and what I need on climbs. That saying, better bike, wheels and engine who knows!
No one seems to have mentioned the size of the wheels with respect to the comparison between MTB and Road Bike. You're likely to be comparing apples with penguins unless you do a bit of googling and calculator mashing on "Gear Inches"
If I was you I'd look for a 50:34 compact, with the 172.5 cranks, as mentioned, and get the best deal on that set that you can. If the rear cassette you get in the bundle isn't quite right, it's pretty cheap to change. (I doubt you'll need to, unless you head to the Alps for a week of hill climbing.)
Road bikes are ace, and the fine details are interesting to learn about, but nothing replaces getting out there and enjoying the countryside.
If I was you I'd look for a 50:34 compact, with the 172.5 cranks, as mentioned, and get the best deal on that set that you can. If the rear cassette you get in the bundle isn't quite right, it's pretty cheap to change. (I doubt you'll need to, unless you head to the Alps for a week of hill climbing.)
Road bikes are ace, and the fine details are interesting to learn about, but nothing replaces getting out there and enjoying the countryside.
Rocksteadyeddie said:
What a refreshing change to see everyone suggesting the (entirely sensible) choice of a compact chainset. 
I was reading that 53x12 is actually a wee bit shorter than 50x11 when you do the gear inch calcs. I'd never thought to try it. If you're spinning out 50x12 even, you're doing bloody well.12x25 or 12x27 on the rear cassette, and you'll get up most things, and are unlikely to miss the 11 cogger on anything but a long, pretty shallow descent that is well sighted. (They're pretty rare really.)
I live on the Hertfordshire/Essex borders and ride predominatly in these areas and Cambridgeshire, which are all fairly flat. I use a 50/39 front combination and an 11-23 rear cassette on both my road bikes, both Campagnolo but one 11 speed the other 10 speed. I do have 11-25 rear cassettes should I know I need that little bit extra if we are going to be riding a particular hilly route. I changed the inner 34 to 39 on both bikes as I was spinning out too easily on a 34 chain ring, I know I could pop it up to the 50 chain ring but the 39 kind of suits my riding.
Rocksteadyeddie said:
What a refreshing change to see everyone suggesting the (entirely sensible) choice of a compact chainset.
horses for courses, it suits the OPs requirements. He lives somewhere flat and likes to spin and keep the cadence high. The benefits of running 50/34 are surely that you also run a cassette like 11-28 to get the wider ranges at the extremes so you can still ride up and down big hills?I personally prefer a lower cadence and achieve the same speed by running a 53t ring, whilst it does not maximise efficency, I am not a elite racer and it just works for my legs and the rides I do, possibly because I spent years running before cycling?
I did notice that spending an a hour trying to achieve a constant 40 kmh in a cat 4 race would have been far easier with a 50t ring however I am too rapha to consider a 50t ring and would rather struggle and suffer with inappropriate gearing than finish higher up the order
Mr Will said:
I'd go for a 12-2X rather than an 11, especially if you are a spinner. 50x12 should get you to 40mph before you are fully spun-out and how often do you need to push at speeds higher than that? I'd much rather have the extra gear in the middle of the block where I'm likely to use it.
Wot he said. /\Rocksteadyeddie said:
What a refreshing change to see everyone suggesting the (entirely sensible) choice of a compact chainset.
I'll buck the trend then 
If you average 17.5-18mph on a mtb, you sound like quite a strong rider so I'd be going standard 53/39 with a 12-27 on the back.What kind of roads are you actually going to be riding?
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