Gearing and compatibility

[bigdom]

I'm after a bit of help from the more enlightened.

I use a Genesis Croix de Fer for commuting, it came with Tiagra, which on the whole is generally okay, although it has the cables out of the side on the hoods so looks messy and annoying for lights etc. It tends to be the go to bike for taking on holiday if we drive anywhere - South West, Italy or South of France, I run panniers on the back so handy for baguettes or beach runs.

I'm thinking of an update, currently it's on Tiagra 4600 - 50/34 and 11-32 (11/12/14/16/18/20/22/25/28/32)

I was first thinking of replacing in 105, although I've stumbled across Ultegra with 46/36, which I think would be better. I don't tend to use 11/12 much. carrying me and not enough consistent miles week in week out - I'm 105kg, the Genesis Scaffold, Panniers & 35c tyres. Even with consistent mileage, i'm always going to be high 90's.

The annoying thing is that 105 doesn't come in 46/36, although there's Shimano RS500 46/36 which I believe I could run with 105?

Would Ultegra be an indulgence for a commuter and last as long?

Any thoughts, apart from #rule 5?

[jamiebae]

bigdom said:

I'm after a bit of help from the more enlightened.

I use a Genesis Croix de Fer for commuting, it came with Tiagra, which on the whole is generally okay, although it has the cables out of the side on the hoods so looks messy and annoying for lights etc. It tends to be the go to bike for taking on holiday if we drive anywhere - South West, Italy or South of France, I run panniers on the back so handy for baguettes or beach runs.

I'm thinking of an update, currently it's on Tiagra 4600 - 50/34 and 11-32 (11/12/14/16/18/20/22/25/28/32)

I was first thinking of replacing in 105, although I've stumbled across Ultegra with 46/36, which I think would be better. I don't tend to use 11/12 much. carrying me and not enough consistent miles week in week out - I'm 105kg, the Genesis Scaffold, Panniers & 35c tyres. Even with consistent mileage, i'm always going to be high 90's.

The annoying thing is that 105 doesn't come in 46/36, although there's Shimano RS500 46/36 which I believe I could run with 105?

Would Ultegra be an indulgence for a commuter and last as long?

Any thoughts, apart from #rule 5?

Why would you want 46/36? It's designed for CX and doesn't give you any lower gears than a semi-compact. In fact your normal compact chainset gives you lower gears than that so if you're spinning your 34 - 32 now when climbing it's going to be harder work with the 46/36.

There are some new bikes coming along with 48/32 chainsets and one of these would do the job, it's also easy to change chainrings if you need to so you could buy a 52/36 and swap the outer ring for a 46 if you really want the CX chainset.

In terms of compatibility the non-series Shimano chainset will work fine if you choose that route.

Finally, before you go ahead you need to check your wheels are11 speed compatible - if you take the cassette off there should be a spacer behind it, if not you'll need new wheels to go up to a 105 group.

I'd go Ultegra personally, I prefer the shifter feel to 105 and it's not massively more expensive if you're going to the trouble of changing everything anyway. Get a compact (50/34) chainset and 11-32 cassette and you're away. The other option is to go for hydraulic brakes at the same time which is more expensive but a nice upgrade, the cheapest way is with these, and 105 gear bits but all Shimano 11 speed stuff is cross-compatible so you can mix and match - http://www.wiggle.co.uk/shimano-rs505-hydraulic-st...

[bigdom]

Thanks for that.

It's more the 50T rather than the 34/36t inner ring. I don't really use 11/12t much on my Surrey/Berkshire commute, appears I use 14-28t on the cassette. Dip onto the 32t on the rear some Friday's bringing home laptop, towel, clothes for a changeover.

Although looking at the cadence thread, appears I'm a grinder rather than a spinner, I suppose I'd better use my existing gears better before I downsize!

[jamiebae]

bigdom said:

Thanks for that.

It's more the 50T rather than the 34/36t inner ring. I don't really use 11/12t much on my Surrey/Berkshire commute, appears I use 14-28t on the cassette. Dip onto the 32t on the rear some Friday's bringing home laptop, towel, clothes for a changeover.

Although looking at the cadence thread, appears I'm a grinder rather than a spinner, I suppose I'd better use my existing gears better before I downsize!

I'm still not sure what you're trying to achieve with the gearing change. The CX chainset is designed to minimise the number of times you have to use the front mech to save time and reduce the risk of having a mechanical failure, and you'll lose a couple of the easiest gears which I guess could be an issue if you encounter a big hill while on holiday.

If you want to upgrade, then do it as 105 or Ultegra are nicer to use and look better than the old Tiagra but I wouldn't get hung up on chainset options.

[bigdom]

Okay, I think I've cracked it, in my mind anyway.

As I mentioned I don't really use either 50/11 or 50/12. So, if I went 46 front and ran 12-30 on the rear, for me, it's looks like i obtain a better selection of closer ratios, losing the really high two is pretty irrelevant in the set-up. I see I can just swap out the 36 for a 34 at the crank to maintain the low side of things.

[upsidedownmark]

FWIW, you're solving a problem that doesn't exist. 50/12 is not 'big' by any stretch, especially if you're not a spinner, and carrying it around/not using it is hardly hurting you, honestly. But at the end of the day, do as you feel suits you best..

[gazza285]

I sometimes ride my cross bike on the road, not once have I thought that I could do with a bigger chainring than a 46. If you think a 36/46 combination will work for you, then go for it, if it doesn't work out new chainrings aren't that expensive.

[Barchettaman]

Why not just swap your current 50 chainring for a 46, and leave everything else the same?

46/34 up front, 11-32 out back. Seems sensible for a commuter/grocery getter that sees hills with weight in panniers.

[Johnnybee]

bigdom said:

I'm after a bit of help from the more enlightened.

I use a Genesis Croix de Fer for commuting, it came with Tiagra, which on the whole is generally okay, although it has the cables out of the side on the hoods so looks messy and annoying for lights etc.

The latest version of Tiagra has the cables hidden (at least on my bike) if you are otherwise happy to stick with it.

[WinstonWolf]

Barchettaman said:

Why not just swap your current 50 chainring for a 46, and leave everything else the same?

46/34 up front, 11-32 out back. Seems sensible for a commuter/grocery getter that sees hills with weight in panniers.

Or the cassette, there's lots of ways to do it.

I live in the fens so I run a 12/25 (10 speed) and it's brilliant as I only have a limited cadence range. I'm always in the most efficient gear I'm just a bit fked if I meet a big hill