[Closed] Single speed commuting & Cyclocross, will I die?

I'm guessing what I would need to do is pick the max speed I'd wish to travel at on the road and the max cadence that I'd be comfortable at and work back from there?

I used to have a Genesis Day One that fulfilled these needs

It came with 42x18T, which was fine for a decent pedally top end but at my 'comfortable' rpm it was happy to run along at 18mph or so... I guess 80rpm for that?

Was more than happy with that off road as well, some hills were a slog but you can get out of the saddle for those.

You won't need a n/w ring. It serves no purpose on an SS.

On 42x18 18mph=100rpm..

I'd be using a nice fat chain. 7 speed if cheap 3/32"

Anything really Bigger the better

lazybike - Member
On 42x18 18mph=100rpm..

No wonder I felt knackered riding that to work 🙂

Spin to win... 🙂

NW because I would run a 1x9 set up in the future or for touring ect.

The gearing on the ride to work I'm willing to compromise and more a little slower to prevent grinding my knees to death every time I'm off road. To be fair 42/18 or 17 seems workable.

The 9 speed chain choice was because the nw chainring works with that spacing, as does the on one sprocket.

sram 9speed chain

scrap that. [url= http://www.charliethebikemonger.com/kmc-z510-hx-chain-18-42-p.asp ]get this[/url] also available in 3/32

best SS chain available ime.

42:16 works well on road tyres. 42:18 for CX tyres on off road. 42:20 for off road on cx tyres.

I'm currently running 42:17 on marathon +s

Will that chain run with the chainring and sprocket I want, it says it's 9 speed spacing.
I'm thinking 42/17 is a good starting point for what I'm after

Would missing links work in a SS set up, I could get two sprockets and perhaps just add a missing link to the chain when adding a larger?

providing you have enough room in the dropouts..yes. You may have enough room that you won't need the extra link.

stick with your 9 speed chain idea.
you typically put far more pressure on a chain on a geared bike pushing a granny ring hard than you ever could ss.
ss chains are relatively heavy, and i would think will wear your NW unduly running a ss chain.
i use sram pc971. works with quick links and all that jazz that i use on geared bikes. and they're cheap these days ( used to be nearly 20 quid - now ~ 12 )
i have 42-20 on my CC. none of the climbs i do ( similar mileage to you ) are particularly steep, but it feels far taller than my 26" SS MTB. i'll probably go 22 next time on the back.
you'll get better at spinning.

You will need two rear wheels because road gearing will not suit CX. For road I ride 42x15 which is geared for 19.6 (275 revs per mile - I count them) mph at 90 rpm. I led a club ride on this gearing last week with an average speed of 20 mph. You spin like me, and this is a fine gear for 21-22 mph. It is a drag into a headwind though.

For CX you'll need lower, i'd guess 42x17 or even 42x18. You can scale speed directly for gearing, but it looks like about 16 ish mph. On my SS MTB running 32x17 I spin out at about 16 mph (26" with 2.2 tyres).

The benefit of a second wheelset is you won't need to swap tyres or sprocket. Of course chain length might be hard to accommodate.

One last point, riding SS CX, you'd be best with adjustable sliding dropouts, because swapping out a back wheel quickly is harder with horizontal dropouts - vertical will retain correct chain tension.

EDIT; as for chains, I ride with a cheap SRAM. No shifting, so no point with anything fancy. I don't need the strength of 1/8" or half link. I did buy one, buy oh it was so heavy!

If you look on Sheldon Browns website I'm sure they'll be a list of chainrings and sprockets that work with a specific chain length.

I got a Surly 110 bcd chain ring for my singlespeed Cross Check and am using the same one now it is in 1 x 9 guise. Never drops or wears out apparently....

I think the CX race gearing depends on the course (quantity of hills, flat and mud).

I'd been considering something like 38:18 ish for a flat race.

Yesterday did the Rossendale cx (which was more like an mtb race) and worried about being under geared on 29er mtb running 32:19 and fairly big tyres. Turned out that gearing was spot on and very glad I didn't swap the rear for a smaller sprocket. Hill was climable and only 50m of flat where came near to spinning out - no need to pedal on the steep downhill bits.

Can't remember what gearing I use for commuting - but always seem to register 18mph on those speed measuring signs 🙂

I've also moved away from ss chains and use sram 9 speed.

For any chain, if you want to swap gear ratios then changing in increments of 4 teeth approximately equals adding / removing one full chain link. So building up with a chain in 2 pieces (one long, one short) and using 2 split links means you can fit different length short pieces for certain ratio combinations. Never had a problem with new / old chain combo jumping with ss unless sprockets are VERY worn (provided you are using a proper ss frame and not some tensioner setup).

More chain wrap the better - 20t on rear - what suits upfront ..