Need some advice choosing chainrings and cassette please.

[SafetyThird]

I'm returning to cycling after a very long layoff. Back in 2006 I was 40 and was a middle of the pack triathlete. Since then I've been through a lot of life changes, cycling/triathlon fell by the wayside and I've lost most of that fitness along with now being a couple of years away from 60. Wanting to finally do something about the loss of fitness, I recently bought a Wahoo Kickr Core and a zwift subscription and am now a month into regularly doing 3 sessions a week on the bike using their Back to Fitness plan which is going well and I'm enjoying.

Looking ahead to the better weather and wanting to get out cycling in the countryside again, I need to change the gearing on the bike. It's still wearing the original standard 53/39 on the front and a 12-25 10-speed cassette on the back. That was fine when I was racing as I was living in a flat country and in the best shape of my life. Now I'm unfit and live in very hilly North Devon and have no chance of getting up the steeper hills on that.

I'm looking at moving to a compact setup of 50/34 which I believe is as simple as changing the front chainrings and I'm also considering changing the cassette to something with a bigger range. The obvious is 12-30 Shimano, which would give me 30-110 gear inches but honestly, even a 12 smallest cog seems more than I'm likely to need given that top speed is never really going to be an issue in the future, and I wondered if something like a Miche Primato 14-30 would be a better option. The Miche cassettes are individually built so I could go even bigger but then I'm into whether the rear mech would cope with it.

Which brings me to hardware and whether what I have will manage those cogs. The bike has early 2000's 105 front and rear derailleurs, an RD 5501 long cage on the back. Shifters are Ultegra flight deck from later as the bike used to be set up with aerobars and bar end shifters but I put it back in road stock a few years ago. How would I find out whether the hardware would manage a 30 tooth or bigger rear cassette?

Would appreciate any advice on choosing something appropriate for on older rider in hilly terrain. Thanks.

 

[SafetyThird]

Hmmm, ok done more reading, I think I'd need a new crankset for compact chainrings as I'm currently on 130BCD and need 110. Time to start looking for some budget cranks as well then.

 

[Cycleops]

Your 105 RD will probably manage a 30t but the only way is suck it and see. You could go to a 34t but you'd likely need a new mech. The front looks like it will come down to manage a 50t.
Plenty of budget ST cranksets around on eBay.

 

[SafetyThird]

Your 105 RD will probably manage a 30t but the only way is suck it and see. You could go to a 34t but you'd likely need a new mech. The front looks like it will come down to manage a 50t.
Plenty of budget ST cranksets around on eBay.

Thanks very much for that, very helpful. I'll probably try a 30T and see how that goes. Might I ask a couple of additional questions of you please?

If I wanted a new rear mech, would you be able to tell me what I need to look for, is it just a more modern version of the 105 or ultegra?

Also, when you say ST cranksets, what does the ST stand for? I googled Shimano ST and didn't give me anything useful. Looking online at chain sets, all the Shimano ones seem to have the spider fixed to the axle nowadays, does that require a different bottom bracket or is it just a different way of attaching the cranks to the axle. I'm assuming I'd need a crank/spider that connects the same way as the one I currently have but I'm not sure what to google to find that. I'm guessing the current type of chainset would require a new bottom bracket as well.

Many thanks.

 

[Jameshow]

A 36t cassette will work with a long cage rear mech.

And a compact double chainset like this....

https://www.ebay.co.uk/itm/30537455...tixoXeJTeO&var=&widget_ver=artemis&media=COPY

 

[Cycleops]

You would be looking for something with a long/medium cage. Sometimes referred to as a 'touring' derailleur. Bit out of touch with the Shimano hierarchy these days. I believe that they do a long cage 105 but you could also go for a cheaper Tiagra.
Sorry ST stands for square taper type BB, which is what you have and the type @Jameshow has linked. A more modern option is the newer Hollowtech 2 piece cranksets, which may be the type you're referring to, which come supplied with outrigger BB bearings, more expensive though.



The axle is fixed permanently to the drive side. The bearing screw into the BB and sit outside.

 

[Spiderweb]

The smallest chainring that will fit your current 130bcd crank is 38t. You will be able to fit a 30t max cassette with the rear mech that you have.

 

[IanSmithCSE]

Good afternoon,

Being a couple of years older than you I can relate to the lack of interest in a 12t sprocket.

That was until one day on the commute I started thinking about gearing and decided that a 48t large chain ring made sense for the way that I ride, I have also tried a 46t big ring but found that a step too far

It has turned out to be a very, very good choice, even on an 8 speed cassette I have a sort of 1 and 1/2x, I rarely need to small ring and when I do I really need the small ring not just 1 or 2 extra teeth on the sprocket.

I can see that it 48x12 might be too low for the steeper downhills if you want to be able to pedal down almost anything but I also have concerns about stoppping so a huge gear and 700x25 tyres can easily be dangerously fast on public roads.

Bye

Ian

 

[SafetyThird]

Thanks very much everyone, that really helps. I've been out of the bike geekery game for so many years and it seems technology has moved on apace. I'll take a look at the hollow tech 2 setup just to see if I would like to potentially future proof my options otherwise it'll be a compact ST chainset on the way. I appreciate all the advice.

 

[si_c]

As @IanSmithCSE says, have you considered a super compact chainset? Rather than 50/34 you could go 48/32 - with a 12-28 cassette this would give you a low equivalent to a 30" gear and with the 48/12 that would be 117". A 46/30 would drop that range to 28"-112" - if you kept your 12/25 with the latter you'd still have a low gear around 32".

This would ameliorate a lot of the issues with cassette choice as your rear derailleur could stick with a range it is comfortable with and the front derailleur would only need to be lowered slightly. In terms of chainset compatibility, if you want to go for a hollowtech 2 chainset, look at Shimano GRX, however it won't match the aesthetics of the bike you have now, so I'd suggest something along the lines of this from Spa Cycles.

 

[ColinJ]

I bought a 1x11 bike for Devon riding in my late 60s. It has a 42/42 bottom gear which is low enough for me up to about 20% gradients. (I have had to walk up a few short ramps steeper than that though.)

Rather than spending a fair amount of cash upgrading your old bike, why not keep that for Zwift sessions and treat yourself to a new, lower-geared bike for those Devon hills?

Planet X are currently offering a similar bike for £749.99 - HERE. You might get 10% off that by subscribing to their newsletter.

 

[SafetyThird]

First decision made, I'm going to upgrade to the Hollotech 2 system. I've had this road bike for almost 20 years and it's the last one I'll ever need for pure road riding (variable geometry, beam suspension) and I've just had a full bike fit so it's very comfortable and setup for me. It's all black so the modern black chainsets will look natural on it. The silver 105 came from my previous bike when I built this one up and never looked quite right. Makes sense to continue the gradual upgrades with a modern bottom bracket while I'm changing the chainset.

So now, compact vs subcompact. Hmmmmmm. Time to do some more thinking.

Another question, sorry for all these, it's been a day of much reading and learning. So, 10sp vs 11sp chain sets. What's the different at the front between the 10sp and 11sp chain sets? I've found the 105 10sp chain sets around but now that I've started looking at subcompacts, I'm also seeing 11sp and I'm unsure what the difference is there, are they spaced differently and would an 11sp chainset work with 10sp cassettes?

A quick look on wiggle shows the 105 R7000 11sp 50/34 chainset available for £130 which seems like a good deal if it works with a 10sp cassette

 

[SafetyThird]

As @IanSmithCSE says, have you considered a super compact chainset? Rather than 50/34 you could go 48/32 - with a 12-28 cassette this would give you a low equivalent to a 30" gear and with the 48/12 that would be 117". A 46/30 would drop that range to 28"-112" - if you kept your 12/25 with the latter you'd still have a low gear around 32".

This would ameliorate a lot of the issues with cassette choice as your rear derailleur could stick with a range it is comfortable with and the front derailleur would only need to be lowered slightly. In terms of chainset compatibility, if you want to go for a hollowtech 2 chainset, look at Shimano GRX, however it won't match the aesthetics of the bike you have now, so I'd suggest something along the lines of this from Spa Cycles.

Just been spending some time on Sheldon Brown's gear calculator and I'm getting different results from your figures. For my 700x23 wheels and a 12-28 cassette, I get the following gear inches for the various front options

50/34 = 32-110
48/32 = 30-105
46/30 = 28-101

If I can get away with a 30T on the cassette with the long derailleur I currently have, the 50/34 with 12/30 gives 30-110GI

Reading about the GRX chain sets, I'm not sure the braze on derailleur mount will allow enough movement to cover the smaller chainrings, I'm trying to find out more about the currently

 

[roubaixtuesday]

Another question, sorry for all these, it's been a day of much reading and learning. So, 10sp vs 11sp chain sets. What's the different at the front between the 10sp and 11sp chain sets? I've found the 105 10sp chain sets around but now that I've started looking at subcompacts, I'm also seeing 11sp and I'm unsure what the difference is there, are they spaced differently and would an 11sp chainset work with 10sp cassettes

I've no experience myself, but this thread from another place suggests you'd be fine

https://forum.cyclinguk.org/viewtopic.php?t=111191

 

[HLaB]

First decision made, I'm going to upgrade to the Hollotech 2 system. I've had this road bike for almost 20 years and it's the last one I'll ever need for pure road riding (variable geometry, beam suspension) and I've just had a full bike fit so it's very comfortable and setup for me. It's all black so the modern black chainsets will look natural on it. The silver 105 came from my previous bike when I built this one up and never looked quite right. Makes sense to continue the gradual upgrades with a modern bottom bracket while I'm changing the chainset.

So now, compact vs subcompact. Hmmmmmm. Time to do some more thinking.

Another question, sorry for all these, it's been a day of much reading and learning. So, 10sp vs 11sp chain sets. What's the different at the front between the 10sp and 11sp chain sets? I've found the 105 10sp chain sets around but now that I've started looking at subcompacts, I'm also seeing 11sp and I'm unsure what the difference is there, are they spaced differently and would an 11sp chainset work with 10sp cassettes?

A quick look on wiggle shows the 105 R7000 11sp 50/34 chainset available for £130 which seems like a good deal if it works with a 10sp cassette

No difference with shimano chain rings between chainrings. I've interchanged a few times. I ran a 11sp crank on a 10sp set up (shifters and rear) for about 20,000 miles as it was a better ratio, better crank length, cheaper and available. And the other year on another bike (11spd set up) the dura ace crank failed and I had to use a 10spd Ultegra one for a few months. Shimano chains are identical on the inside and its only the outer plates which are thinner to fit in a tighter cassette with more cogs.