Single chainring & rear derailleur - what chainset?

pete99

I'm going to be putting together a new wet/winter commuter based around an MTB frame and using lots of bits from the current (very elderly) incumbent.

But since I need a new chainset I'm hoping to go with just one chainring at the front. For London commuting a fair-sized single chainring gives plenty enough range with a 9-speed cassette.

Any suggestions for a (not too pricey) one-chainring chainset, ideally with some sort of chain guard? There's a few around intended for Alfine/Rohloff-type hubs but they all seem to be 170mm, which is a bit short.

The plan B is to use a 53/39 road chainset and replace the outer ring with a cyclocross bashguard. But can I put a road chainset on an MTB frame? Is it fraught with potential difficulties?

Any tips, too, for keeping the chain in place with a sort of guide would be very welcome.

Thanks.

wgwarburton

Hi,
Stronglight 55 would probably suit plan A.

Cheers,
W.

nicklouse

TBH any will do and fit a ring of a size you want.

if an MTB frame be aware that the inner ring of a road crankset (double) can foul the chain stay if you go too big.

Berk Bonebonce

Yes, as per the first reply, check out the Stronglight website. Last time I looked I believe they did some single CX-type chainsets with dual bashguard. A single chainset can be a real bummer if the chain keeps unshipping. Spa Cycles are good for most things Stronglight.

And Stronglight (JIS taper) square taper chainsets fit on SHimano bottom bracket axles. All you need to aim for is a satisfactory chain line; not as if you have got a front mech to keep happy.

ride_whenever

Go for one of the sturmey archer ones, they're pretty cheap and come with bash guards either side to help keep the chain on.

The Rookie

My commuter is a road frame running an older (square taper) MTB crankset using a single speed secific chain wheel (availabe for about £35 upwards), I'm using a road front mech as a chain guide to keep the chain on, it would probably work just as well with a normal geared chainring to be honest.

Simon

pete99

Thnaks everyone for the useful info. The Stronglight chainset look great, but for one thing – it, too, only seems to be available in 170mm. Anyone recommend something similar in 175mm?

iratnl

The race face ride XC comes in 175

pete99

The Race Face one would be great... except it seems to have a biggest chainring size of 34t. I'm not sure you could add a significantly bigger ring given the bashguard,

Hmmm. It's a tricky one.

The Rookie

As I posted above, you can add SS chainwheels to any crankset, you can get upto 48T to fit to a normal Shimano 4-arm, I'm running a Saint on my commuter, Renthal and Middleburn both do SS wheels of over 42T that would be suitable for a commuter and you can keep your existing BB and cranks. Use a chainguide and no need for a Bash.

Simon

wgwarburton

Hi,
I'm struggling to see that a 5mm difference in crank length would be an issue on a winter commuter. I ran a 165 left crank against a 170 right for a good while and I don't recall being able to tell the difference... It's pretty subtle.

Cheers,
W.

pete99

The Beginner: some good thoughts.
But when you say a chainguide, what sort of thing exactly is best? Any recommendations?

WGWarburton: maybe it's psychological, but when I used to ride another bike with 170mm cranks I always felt I had that little bit less power. It seemed to feel slightly but noticably different from 175mm.

pete99

The Beginner: some good thoughts.
But when you say a chainguide, what sort of thing exactly is best? Any recommendations?

WGWarburton: maybe it's psychological, but when I used to ride another bike with 170mm cranks I always felt I had that little bit less power. It seemed to feel slightly but noticably different from 175mm.

The Rookie

I went for a budget chainguide - its a Shimano sora front mech (£10 off ebay), otherwise the Superstar guide comes well recommended as being light/cheap and doing the 'exactly what it says on the tin', although as most 'one by' commuters use a larger chainwheel than you can get a chainguide for it may be a front mech for you.

I've 'tuned' mine by removing the whole cable leverage arm and other unnecesary bits and got it down to 100g.

Simon

jomoj

I'm running a 42 up front and 11-25 cassette which is more than enough for my 25 mile round trip, didn't use a chain guide and I loved the clean look of the single ring. I didn't drop the chain for weeks and then it happened twice in a row as i was accelerating. I shortened the chain and that helped but it would still do it occasionally when changing to a smaller sprocket at speed, slipping off onto the crank.

I've now reinstalled the front mech as a chainguide which has solved the problem completely but spoiled the aesthetic. Must admit I'm tempted by a chain device but am not sure if you can fit the BB mounted ones on a hollowtech 1 type BB with internal bearings.

The 'Paul's' chainkeeper looks very nice but £40?? The other option is an outer ring guide - Thorn cycles do one for £20 and then add a 'dog fang' on the inside for £4

Drfabulous0

You want a bashguard to stop the chain dropping off the outside and a sharks tooth to stop it coming off the inside, works and looks better than a front mech.

The Rookie

They are options, yes, and the bash doubles as a trouser guard where needed, but most bashes are heavier than the front mech, also if using an MTB style crankset you'll struggle to get a bash for a 44/46T front wheel size.

Simon

Blue Meanie

Chain Watcher

http://www.edinburghbicycle.com/ebwPNLq ... ctID=12749

Called so, because it watches as your chain falls off
(Actually, some riders have good experience of such)